# Designing a DIY silver cell



## 4metals

On another thread about refiners in Europe, posts between myself and Shark lead to questions about making a reasonably productive Silver cell and how to build it to simplify harvesting the crystals. I found on line a steeply sloped bottom tank called an inductor tank from Tank Depot 60 Gallon Inductor Tank 62205 | Tank Depot that will allow a 4" drain line for crystals to drop. At 30" in diameter it should be relatively easy to cut the top and add anode buss bars and cathode bars and a cathode rocker to a 21" square cut into the top. After doing some math and configuring just what would fit in that space to determine the size and quantity of cathode plates, I realized that we could make a system with 3 anode buss bars to hang anodes in anode bag baskets and 4 cathodes and make a system to run from a 250 amp rectifier that could produce up to 630 oz in a 24 hour day. 

Then I thought, "how many of our members would actually be interested in a cell that large?" So I slowed my thought process down a bit and figured what may really be needed is something to go in-between the stainless bowl cells and the smallest of the commercially manufactured cells. 

Bottom line is, before we start designing, (which would be a good community project to take up), what is a realistic consensus of opinion as to how many ounces a week would a reasonable cell produce? Keeping in mind the size of the power supply needed and what a smaller refiner could feed the thing consistently. 

So before we start designing something no-one is actually interested in making, just how big should this cell be. Answers in T.O. fine silver produced weekly. 

What is the consensus?


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## Lou

Not a fan of the geometry of the tank but I sure would buy one if it came in a squared up version. I got rid of all my big cells about 5 years ago and every now and then I'm like, "crap! why did I get rid of these, again??"

Realistically, most people aren't going to setup to autonomously run, or go scrape/empty a 24/7 cell operation. So if you rated it at 315 ounces/day * 4 days a week (with one day being electrolyte make up, slimes recovery), you would be at a reasonable amount of silver produced...1200 ounces every week assuming what gets kicked out of the electrolyte goes back into it.


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## 4metals

Lou said:


> Not a fan of the geometry of the tank but I sure would buy one if it came in a squared up version.


I agree with a squared up version but the place those tanks fail is on the welds of the taper. Since this is a DIY effort, and most of us are not proficient PVC welders, that is why I went with rotationally molded.


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## Shark

For really small scale this design was one I have looked at for a while. Unsure of the plastic it is made from.









The Catalyst Fermentation System


The catalyst fermentation system can be found online at Adventures in Homebrewing along with other brewing equipment, hardware, accessories and fermentation supplies.




homebrewing.org





The following comein 3, 7.9 and 14 gallon but have really small openings for the drain end. 









FastFerment 3 Gallon Conical Fermenter


The 3 Gallon FastFerment is your all-in-one conical fermentation solution. No siphons, no secondary fermenting vessel to sanitize, no extra bungs and airlocks. Perfect for making beer, wine, or cider.




www.midwestsupplies.com





Most these can be found cheaper on Amazon as well, here is a real budget one. 



https://www.amazon.com/FastFerment-Conical-Fermenter-Fermenter-fermenter/dp/B077X2261T/ref=sr_1_11?keywords=plastic+fermenter&qid=1661187759&sr=8-11



These would be nice, as anything designed to fit one should be easily scalable to fit the others. For me anything 50TOz and up is a huge jump, and 100TOz in my thinking is where it starts becoming small scale serious. But in range for many members who are actively working at growing. 

The square tank, as Lou mentions would be a big plus and most plastics can be molded to some degree fairly easy, but is always a risk. On the 3 gallon tank I might try it where as the larger, more expensive ones I would seriously hesitate.


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## 4metals

Shark said:


> For me anything 50TOz and up is a huge jump, and 100TOz in my thinking is where it starts becoming small scale serious.


when you are talking in the range of 50 oz a week, I think the best option would be to scrape, or let a small cathode rocker scrape, and allow the silver to lay on the bottom of an off the shelf tank. 
14 Gallon Polypropylene High Temperature Tamco® Tank - 12" L x 12" W x 24" Hgt. | U.S. Plastic Corp.

That's pricey but polypro will stand up the longest, PVC is better but this is just to show size.


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## Shark

I like the idea of the self cleaning cathodes. As much as a larger cell, having some self maintenance would be a time saver. 

I am trying to picture the placement of the square catch tank. Would it just sit under the cell like a catch pan, or be attached in some way to the cell?


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## 4metals

Whoops didn't mean to post that yet. 

when you have processed for a week you could have a drain valve a few inches up the side to drain off the electrolyte, lift off the anode cathode configuration, which we make to place on top as a unit, and lift the tank to pour out the rest of the electrolyte and gather your crystals. 

For example with a 5 amp rectifier and a 0.2sq foot anode you can deposit 13.5 oz per day and it could lay at the bottom until you process all of your anode material. (in theory)

I was hoping for visions of grandeur and, as Lou suggested in the 1200 oz aweek range (with Fridays and weekends off)


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## Shark

A larger cell would be great. I am mainly thinking of something scalable to fit a larger crowd. A while back I scaled the stainless bowl many use down to a half liter size for experimenting. It worked well enough, but I had more silver than I thought i did then.


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## Shark

4metals said:


> when you have processed for a week you could have a drain valve a few inches up the side to drain off the electrolyte, lift off the anode cathode configuration, which we make to place on top as a unit, and lift the tank to pour out the rest of the electrolyte and gather your crystals.


Tilting furnace type stand?

Edit: now I am thinking bigger.


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## Shark

Quick glace through the Tank Depot web sight shows a variety of tank sizes, (should have known it would) and keeps the scalability idea in play.

Edited for spelling.


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## Martijn

I think for the most hobby refiners a small simple cell will be enough. You can run quite a bit if you take your time with a one liter cell.


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## 4metals

In the early 1980’s I ran 18000 oz in a 10 gallon fish tank in my barn. So yes it can be done. But I thought a discussion concerning the design, and the why behind it, would be interesting for some members. 

A full discussion would include copper build
up from processing sterling and analysis to keep the cell running by titrating the solution and adding nitric acid to maintain the silver nitrate level in the electrolyte. 

Personally I already know how to do this stuff but if there is interest it’s worth doing. But if all members are looking for is a stainless bowl
Silver cell then who am I to argue.


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## Shark

Martijn said:


> I think for the most hobby refiners a small simple cell will be enough. You can run quite a bit if you take your time with a one liter cell.


True. I have also turned down silver because I knew I could not refine 50 to 100 pounds in 2 to 4 weeks. A bowl just wouldn't cut it.


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## Shark

4metals said:


> In the early 1980’s I ran 18000 oz in a 10 gallon fish tank in my barn. So yes it can be done. But I thought a discussion concerning the design, and the why behind it, would be interesting for some members.
> 
> A full discussion would include copper build
> up from processing sterling and analysis to keep the cell running by titrating the solution and adding nitric acid to maintain the silver nitrate level in the electrolyte.
> 
> Personally I already know how to do this stuff but if there is interest it’s worth doing. But if all members are looking for is a stainless bowl
> Silver cell then who am I to argue.


The entire process start to finish is what interests me. Have a solid idea before needing it, is jump start in growing.


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## Shark

Here is one that might work for Lou. Still has potential to run in the volume range he needed and maybe into the first thoughts 4metals had as swell. I am not sharp enough to figure in my head the volume needed to produce in TOz.






56 Gallon Total Drain Rectangle Tank | Plastic-Mart


This 56 Gallon Total Drain Rectangle Tank measures 38" L x 20" W x 26" H and is manufacturered by Ace Roto-Mold / Den-Hartog. Most stock ships in 48 hours!




www.plastic-mart.com





Edit to add: 
For those needing something a bit smaller.






Cone Bottom Rinse Tanks Archives - Go To Tanks


Rinse Tanks are smaller Cone Bottom Tanks used for a variety of special utility needs and custom applications and are ideal for dispensing fertilizers, oils, soaps and detergents. When needing tanks that provide complete drainage, these tanks are the perfect choice. Tanks are available in sizes...




gototanks.com


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## 4metals

It’s all about the surface area of the cathode. The tank size has to be able to house the size of the cathode. Commercial systems run at 25-50 amps per square foot. And each amp will deposit 3.5 grams of silver an hour. So the size of the rectifier determines the rate you make silver. And the number of amps you can deliver determines the size of the cathode to stay in the 25-50 ASF range. The volume of the electrolyte is just like the volume of a goldfish bowl, the smaller the bowl the harder it is to keep it in balance.


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## Shark

Math test. 

A six square foot cathode, running at 50ASF. Total of 300 amps. Possibly produces 33+ ounces of silver per hour. Or over 810+ ounces in 24 hours of continuous runtime. 

That I would love to see happening!


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## orvi

Maybe bit late to the discussion, but I agree - this is a very good idea, wheather it only end up in discussion, or collective brainstorming with end result - checked by professionals 
For me, the best idea would be design that is convenient to use on daily base, and automatic scraping may be the nice feature. Also we have professionals here with decades of experience, so any culprits can be detected in early stages as they certainly know more than others.

And also, I think it could be scalable by varying the dimensions of the apparatus to fit one needs. 
Speaking by myself, I am certainly not capable to push even 1 kg silver a week. I know that many members here would welcome the design that will allow multiple kg/week. And some maybe few kg/day. 
But these numbers aren´t that wildly distant in the means of setup - of course, dimensions of the tank/anodes/cathode/etc would be different, but the setup remains the same.


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## markscomp

Shark said:


> Math test.
> 
> A six square foot cathode, running at 50ASF. Total of 300 amps. Possibly produces 33+ ounces of silver per hour. Or over 810+ ounces in 24 hours of continuous runtime.
> 
> That I would love to see happening!


not average for home / small bus refiner [- the 300 amps } 

use 37.5 amps times 3.59 is 134.65 gm silver

lets say gram of silver at 16 divided by 31.1 rough in at .5$ thats Point 5 - (lower than today but roughly average over years and easy divide (able) per gram) so 67$ +/- so you are creating 

so with purchase, cost of electricity per hour or amp hour, maintenance, lots of labor, chemicals and a profit 

little bit of long term funds to go out toward building purchase, taxes etc.........


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## Shark

How did you get to the 37.5amps and where does the 3.59 come from. I can see where your going with this, I am just missing something somewhere.


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## markscomp

Commercial systems run at 25-50 amps per square foot - was posted

sorry it may be worse than i thought (3.59 may be a typo ) 3.5 per is what was posted also


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## markscomp

Shark - you get the jist run with it


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## Shark

Looking back at the various tanks most of those I found could be questionable as to how much space would be usable for storage of the crystals in the bottom while building up more silver growth.

Do most prefer to save in crystal form or do they melt the silver soon as possible? 

Another question is would the people buying such quantities prefer bars or crystal? 

Am I over thinking that seemingly smaller space?


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## Lou

I think we should do a really awesome silver cell thread. We should then do a wohlwill cell so we can trash talk them because they're terrible wastes of money.

Shark,
The crystal was bulky and mine was fine like sand because I never wanted (in production, anyway) big dendrites of silver crystal, so it was easier to melt it.

I think unless you're growing huge crystals that have a really cool look to them (HT patch used to grow these), people want bars.


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## 4metals

Lou,
Weren't you using grain as anode material? I think it was you,but maybe not, my gray matter is dropping off at an exponential rate these days.


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## netgeek3

Guys, this is of intense interest to me, as our volume has exploded, and this addresses one of our outstanding issues. We cannot keep up with the amount of silver we're extracting, and it's something we really want to leverage as the economy prepares to take a dump. The ability to process 1200ozt per day would help us tremendously, versus the scaled up and multiplied bowl system we've been using. I know there are commercial systems out there, but not spending many $$$ is very attractive to me. Also, I have a lot of DC rectifiers available to me at no cost, so leveraging that is something we are trying to do with each plating line that we set up.


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## Shark

Thinking out loud here…..

What would be the minimum angle for the fine crystal to move down to the exit point under its own power? If the angle is steep enough this could help eliminate one point of manual labor. This leads back to the original round tank as well. I would need to figure out how much cathode in square inch’s or feet would be needed to produce the amount of silver we need to produce. This would help me picture the volume plus needed holding space.


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## 4metals

The Moebius cells made to sit on the floor don't have such a steep slope, maybe 15-20º. The movement of the scraped silver crystal is enhanced by a circulating pump which pumps solution from a bar across the back of the slope downward towards the collection trough. It is quite effective because there is never much Silver needle accumulating on the slope.


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## Shark

Check my math..

We need to produce 1200 ounces in a 4 day work week. This would be 300 ounces in a 24 hour day. Or 12.5 ounces per hour. The way I have always done things I would be shooting for 13 ounces per hour to allow for days that didn’t go as planned. So, if I figured right, 13 ounces an hour starts to sound more reasonable. Now figure the cathode area needed next.


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## 4metals

You will never get the 300 ounces in a day without running high (>99%) Silver to start. That is because of the copper in the cell, I always figure on 90% so I would bump up the 300 to 333 to get the 300 produced. And the consistency is a function of free nitric acid content and how your nitric is added as well as a list of other scenarios affecting production. 

All of these systems that give a convenient 3000 oz per week estimate or larger based on the number of cells, are living in a "perfect world" bubble. I've never lived in one of those! Too many things can vary like the copper content in the anodes, the electrical connectivity of the buss bars, the nitric acid content, the silver nitrate content, and the list can go on. So the estimates are just that. If you buy or design a system because you need 3000 ounces in X time, be prepared to be disappointed.


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## Shark

So, I am only allowing for 12 additional ounce per day and 33 would be more realistic in the real world. That is the experience that I don’t have. Thanks.


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## Shark

A goal of 1350 ounces in a 4 day week, or 96 hours.
Equals 14 TOz per hour.
5 square foot of cathode at 25 amps per square foot equals a total of 125 amps.
125 amps per hour at 3.5 grams an hour makes 14 ounces an hour.
Or, at 50 amps per square foot would require 2.5 square foot of working cathode space. Producing the same 14 ounces per hour. I think I am starting to see the general idea behind the cathode to amp per ounce but my head may fall off anytime now..


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## Shark

netgeek3 said:


> Guys, this is of intense interest to me


Your input would be appreciated. The more people involved the better we can make this for the most people. With out the help from others it takes forever to learn this stuff.

And I will stop using TOz in place of ozt.


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## Shark

Why is the rectangular shape consider better than the round shape?


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## 4metals

4metals said:


> It’s all about the surface area of the cathode


This can be a little misleading so let me clarify it a bit. 

The cathode plates are just a site for the silver needles to grow. They are also the largest surface area hanging in the cell which is why I said the tank size has to be able to house the cathode. But as far as current density is concerned, the amperage per square foot is calculated based on the area of the anodes. This poses a bit of a conundrum as the anodes are constantly getting smaller. I always try to have some worn down anodes mixed with some full sized anodes to preserve the "approximate" area. Cast anodes molds made by silver cell manufacturers are tapered so they are fatter at the top and thinner at the bottom so they maintain a more consistent surface area as they erode A general rule is cells run at 25-50 ASF. Most prefer to aim for the 25 ASF figure knowing as the anodes shrink the ASF will increase but it will remain well below the upper limit.


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## 4metals

Shark said:


> Why is the rectangular shape consider better than the round shape?


Silver cells are usually square or rectangular because you can fit more volume per unit of floor space in a square tank than a round tank. Plus the relationship between the anodes and the cathodes are always parallel to each other so it allows for better use of space. 

Of course all of this flies out the window when you run a silver cell from a 2 liter stainless bowl but I'm talking about large scale producers.


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## Shark

4metals said:


> Cast anodes molds made by silver cell manufacturers are tapered so they are fatter at the top and thinner at the bottom so they maintain a more consistent surface area as they erode A general rule is cells run at 25-50 ASF. Most prefer to aim for the 25 ASF figure knowing as the anodes shrink the ASF will increase but it will remain well below the upper limit.


Would these be the same basic shape as the copper cell anodes, using the basket so they could progressively drop down as the lower end is consumed? I am thinking this would keep the amps needed within the usable range when done right?


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## 4metals

No, the anodes are placed into the cell and immersed just shy of where the anode hook grips the anode so the same quantity of anode is submerged every time. It is thicker at the top as the tops dissolve faster than the bottom. This is a mold for casting anodes, from the photo you can see the shape. 


The silver is poured into the mold and the reducing flame from one of the torches helps the keep the anodes free of oxygen. You can see the taper.

One of the down sides to Moebius cells is that about 20% of the silver needs to be recast into new anodes because they remain out of solution to hold the anode in position. By contrast a Thum cell completely consumes the anodes eliminating that step. But the two cell types have other trade offs which maybe we should discuss first to decide which type of cell we want to design.


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## FrugalRefiner

4metals said:


> One of the down sides to Moebius cells is that about 20% of the silver needs to be recast into new anodes because they remain out of solution to hold the anode in position. By contrast a Thum cell completely consumes the anodes eliminating that step. But the two cell types have other trade offs which maybe we should discuss first to decide which type of cell we want to design.


I'd be interested in your views on that. Here are some considerations to start (I think).

As you've said, a Thum cell eliminates having to remelt and recast the anode stubs.

A Moebius cell can usually output slightly higher purity.

A Moebius cell requires less attention to knocking down needles that can short out the cell.

A Thum cell requires a "candlestick", or some similar device to make electrical contact where Moebius anodes hang from a buss bar.

What else would you add?

Dave


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## Shark

4metals said:


> But the two cell types have other trade offs which maybe we should discuss first to decide which type of cell we want to design.



Will it have a factor in choosing the cell shape, round or rectangle? Or would the discussion of which type cell help determine that? 

Myself, I am good with which ever you think best. This is new territory for me.


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## 4metals

FrugalRefiner said:


> A Thum cell requires a "candlestick", or some similar device to make electrical contact where Moebius anodes hang from a buss bar.


My idea of a candlestick is a fat anode with a 3/8” tapped hole that I thread an anode hook into. Just keep it on top of the anode pile. 



FrugalRefiner said:


> A Moebius cell can usually output slightly higher purity.


I’d like to see some background to that statement. May be true, I haven’t seen it. 

If it weren’t for the difficulty in scraping the cathode when it’s horizontal I would be saying Thum is the way to go. But it will take a concerted effort of the minds to figure that one out.


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## Shark

4metals said:


> If it weren’t for the difficulty in scraping the cathode when it’s horizontal I would be saying Thum is the way to go. But it will take a concerted effort of the minds to figure that one out.


How much force would be needed to hit the bottom of the cell to break the growing crystal loose?
My thinking is plastic would be easier to get the impact right than metal, but I have nothing to base that on other than watching plastic react to impact with liquid in it. Of course crystal growth would be a big factor as well. Like a sonic cleaner maybe?
Would it disturb the slime's in the bag?



4metals said:


> My idea of a candlestick is a fat anode with a 3/8” tapped hole that I thread an anode hook into. Just keep it on top of the anode pile.


I hang smaller copper anodes by doubling over the end of a heavy wire and hammering them tight in the drilled hole. They do come loose occasionally, but enough work to not need titanium screws or hooks. Hanging them from a buss bar as well.


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## snoman701

But outside of shops that are already ISO9001, what is the point of running a cell? Who wants product that isn't coming from a vetted source in any quantity that makes running a cell worthwhile.


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## 4metals

snoman701 said:


> Who wants product that isn't coming from a vetted source in any quantity that makes running a cell worthwhile


 Because I’ve seen many systems from vetted sources, respected vetted sources, who don’t exactly have stellar customer service. We are not doing rocket science here. We may actually come up with a better mousetrap.


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## snoman701

I'm not talking about the system, I'm talking about the product, fine silver. 

What are the actual advantages to making 999 silver? Your stamp doesn't mean much unless you are huge. 

This can all be done really really cheap with off the shelf products...but the end result is 999 silver that you still can't move at a premium because you aren't a multimillion dollar corporation.


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## orvi

snoman701 said:


> I'm not talking about the system, I'm talking about the product, fine silver.
> 
> What are the actual advantages to making 999 silver? Your stamp doesn't mean much unless you are huge.
> 
> This can all be done really really cheap with off the shelf products...but the end result is 999 silver that you still can't move at a premium because you aren't a multimillion dollar corporation.


Sometimes you find buyers like jewellers, who make his own alloys and need high purity silver without contaminants. And often they are willing to pay spot or above spot for it - as buying investment ingots can be more expensive.
Also, from fine silver, you can make silver compounds which could be sold as reagents for bigger companies or institutions. AgNO3 crystals, silver acetate, silver sulfate etc.

Not a huge volume can be pushed by this strategy, but it is a little sweet bonus for you if you can do this 
I lived through the times, when I was paid 83% spot for silver, 999. Below 999, 80%... I do not want to fall into this again. Prices paid here are very bad generally, and without kilos and kilos... You barely make any profit doing silver. Unless you find other buyers, who are interested in the product with added value.


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## Shark

In my case sterling averages 80% of spot if small jewelry and 85% if larger items. If I can bring 99.9 the price goes to 96% with a very small minimum.

My main reason is learning, from some of the most knowledgeable people I know on the subject. Jump in and throw out some ideas.


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## snoman701

orvi said:


> Not a huge volume can be pushed by this strategy, but it is a little sweet bonus for you if you can do this
> I lived through the times, when I was paid 83% spot for silver, 999. Below 999, 80%... I do not want to fall into this again. Prices paid here are very bad generally, and without kilos and kilos... You barely make any profit doing silver. Unless you find other buyers, who are interested in the product with added value.


That's just it, the volume sucks. And yes, price on silver sucks. I get 92% on small amounts, and my buyer will complain that he's not making any money. If I take him 1000 oz he still won't pay on gold, and he'll up it to 93%. Obviously there are better buyers out there, but the difference between 93 and 95 is only $382 right now. That's not worth going out of state to witness a melt. The silver market on high % silver products isn't even close to what it used to be. Grandma's flatware was sold years ago. 

The current premiums on physical silver are high, but they are high because that's the cost of business on the other end. 

Anyway, the way I figured I'd set it up are Tamco tanks. I'd use a pool skimmer basket to hold the anodes, and have it nest into a hole cut in a sheet of plastic big enough to cover the entirety of the tank, and rest on the rim (or a painted plywood frame if the tank isn't sturdy enough). The sheet of plastic would have two other holes in it, one for your cathode connection and one for a piece of stainless tubing. The stainless tubing is used to siphon the tank empty. No holes cut in the tank. They are stress risers and that's where your tank will start leaking. Once empty, you just pick the tank up and dump it into a large collander or other draining vessel. Home Depot cement mixing tubs are the backbone of any small refining operation. Anyway, the tank empties into a 15 gallon drum by gravity via a siphon. Once you clean everything out you put your top back on and lift the 15 gallon drum high enough that the electrolyte will siphon back in. No pumps to break. The whole thing is controlled via a Sorensen 12v50a power supply. Depending on the tamco tank, you can set it up either Moebius or Thum style. On top of your sheet of plastic that is holding your anode basket, you place an inverted rubbermaid container that is hooked up to negative pressure exhaust. This will minimize your need for high room turnover air flow.


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## Shark

snoman701 said:


> That's just it, the volume sucks. And yes, price on silver sucks. I get 92% on small amounts, and my buyer will complain that he's not making any money. If I take him 1000 oz he still won't pay on gold, and he'll up it to 93%. Obviously there are better buyers out there, but the difference between 93 and 95 is only $382 right now. That's not worth going out of state to witness a melt. The silver market on high % silver products isn't even close to what it used to be. Grandma's flatware was sold years ago.
> 
> The current premiums on physical silver are high, but they are high because that's the cost of business on the other end.
> 
> Anyway, the way I figured I'd set it up are Tamco tanks. I'd use a pool skimmer basket to hold the anodes, and have it nest into a hole cut in a sheet of plastic big enough to cover the entirety of the tank, and rest on the rim (or a painted plywood frame if the tank isn't sturdy enough). The sheet of plastic would have two other holes in it, one for your cathode connection and one for a piece of stainless tubing. The stainless tubing is used to siphon the tank empty. No holes cut in the tank. They are stress risers and that's where your tank will start leaking. Once empty, you just pick the tank up and dump it into a large collander or other draining vessel. Home Depot cement mixing tubs are the backbone of any small refining operation. Anyway, the tank empties into a 15 gallon drum by gravity via a siphon. Once you clean everything out you put your top back on and lift the 15 gallon drum high enough that the electrolyte will siphon back in. No pumps to break. The whole thing is controlled via a Sorensen 12v50a power supply. Depending on the tamco tank, you can set it up either Moebius or Thum style. On top of your sheet of plastic that is holding your anode basket, you place an inverted rubbermaid container that is hooked up to negative pressure exhaust. This will minimize your need for high room turnover air flow.


Beat me to it


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## 4metals

snoman701 said:


> What are the actual advantages to making 999 silver? Your stamp doesn't mean much unless you are huge.


There is still money in sterling silver refining, even if you don't make it into fancy bars with a recognized logo on them to sell for big premiums. 

Take a small refiner wh buys in sterling for 10% under the fix. These are the guys most small town jewelers go to to sell their scrap. With a setup to produce 3000 oz a week, which is easily run and maintained by 1 employee. (including the daily titration) That puts labor for the silver refining guy (or gal) at $1000 a week on average. 

Sterling typically contains half an ounce of gold for every 1000 ounces. Refiners don't pay on that gold because......... well they don't! 

Processing enough sterling to yield 3000 ounces, about 3,250 ounces and refining it in house will allow them to save the 2% refining fee so in addition to the 8% they kept even when they shipped it out, they get to keep (at $19 silver) $ 1,142. They will also recover the gold from the slimes so add in another 1.5 ounces of gold ($1750/oz) or $2625. This makes a margin of $3767 before chemical costs and labor. 

As far as selling your silver, there are lots of the IKoi bar-making machines being sold to people who do not refine, they just make bars on silver they buy. And make a nice premium. And silver bars are hot today, hotter than the silver supply. I know a few refiners that supply 1000 ounce bars to these guys for 10 to 15¢ under because it's hard to get silver to meet the demand today. 

So you don't need the big name to sell your silver and you can make it work profitably. Just another line of income for a versatile refiner.


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## 4metals

This style still needs you to manually push the silver needles off the shelf to fall into the easily lifted out basket. The down side is the scraping every 4 hours or so. no getting around that. This is the basket for the anodes.


A piece of PVC angle the length of the sides on the long side of the tank will allow this to be slid forward and make room to push the silver off the cathode and let it fall into the basket, then just slide it back and power up again.


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## 4metals

Shark said:


> How much force would be needed to hit the bottom of the cell to break the growing crystal loose?


They snap off from the cathode and never, or rarely, peel off clean. so some silver is always on the plate. That never seems to be an issue with a Moebius cell but with a Thum cell being horizontal I think a scraper may bind up. 



Shark said:


> Like a sonic cleaner maybe?
> Would it disturb the slime's in the bag?


I do not know if ultrasonic vibration would loosen the crystals but it may also get the slimes dancing around in the anode compartment and likely cause them to work through the bags.......not good!


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## Shark

Wouldn’t this need welding or can they be bought in this shape at a reasonable price?

If the anode basket is slid out of the way, could the cathode be lifted high enough and safely, to dump the silver into the lower basket?

Maybe with the right cathode rocker?

Would need to be narrow enough to clear the angle resting area.
Would need to be sure the basket moves far enough to clear the cathode when raised.


----------



## 4metals

View attachment 7C3BC788-DE11-479E-98DA-1110D82B4EB3.mov

This is a photo of a moebius cell cathode rocker on a single cell of a larger system. The newer systems use a round arm dropping down to dislodge the needles but it is the same principle.

The mechanics of breaking the needles off on a vertical system is gravity is on their side. The needles break off and drop so the scraping arm is never "snowplowing" a pile of crystals. Plus, without a large drive wheel the arms move back and forth about 8", enough for 2 (in this case) downarms to scrape the entire length. 

With a horizontal plate you would need to cover the entire length in a single stroke with a plow to move the crystals off the end. I do not know how much resistance a pile would put up over time because, even on a vertical system, eventually the plates need a little manual scraping help. So while a plow may perform great on a clean smooth cathode, once it is roughed up by firmly anchored crystals, it may, or likely will, inhibit the plowing. 

I think the mechanics of lifting the cathode to make an incline and then scraping it would present more of a challenge because now, instead of having a scraping component, you also need a co-ordinated lifting component. Manually scraping once every 4 hours isn't hard to do, but having to do it makes your cell only producing for an 8 hour shift. 

I know one shop that has his rectifier on a timer for 4 hours to shut down. It allows scraping every 4 hours without worry of shorts from missing a scrape. He scrapes the cell first thing in the morning, 4 hours later, another 4 hours later, and first thing in the morning because the cycle allows it to run 4 hours when no one is there before shutting off. This effectively makes it work a 12 hour day. Still foregoing 12 hours a day and weekends. While this is more efficient than just 8 hours a day it is still 35% of what it could produce if it ran 24/7.


----------



## Shark

With that setup the angle of the bottom and the catch basin to the side makes a lot more sense. That cathode rocker is more advanced than what I was thinking. I like it.


----------



## snoman701

You guys are thinking too hard.

I used a piece of stainless steel expanded metal as the cathode. The "scrape" in this case need not actually scrape it, just knock off the needles. They then fall to the bottom of the tank. In my case, I wasn't even scraping, just tap tap with a hard metal object.

Every few days I'd pull the cathode and soak in nitric to clean it up, effectively making new electrolyte.


----------



## Shark

Waiting for others to pitch in.


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## markscomp

Shark said:


> Waiting for others to pitch in.


still looking for cost analysis of a larger - (than a home set up)- of the cell - something that a normal 200 amp service can handle (or two 200 amp service combined) can create - managerial accounting number with an average cost per 1 amp broken into final tally of a 1 toz silver We do not do chemicals nor will we do fire anything. But a small-scale analysis may be beneficial to all 

{ sorry ....... edit to really mean that we acquire things and resell or then tear down material {not shred - yet] and then have material sent out to United States refiners - sorry - Kind of like silversaddle does} Mark


----------



## Shark

That one is over my head. Also, it is one of the things I need to learn as well. For me to run a silver cell using 30 or more amps at this time, I either drop a copper cell or look into some serious rewiring. The next step would be a larger building with better power, not tied my current power at home. I am still in the hobby phase now, but there is opportunity to grow, I just have to decide which way I am going yet.


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## snoman701

It's minimal cost for silver. Copper the cost of electricity starts to add up. 

It's a lot of current, but a low voltage, so the actual power utilization is small.


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## snoman701

I am more interested in a cell like this for purposes of breakdown. I get a lot of low grade silver material. The breakdown cell is an effective way of getting it to a much more pure state without the release of as much NOx


----------



## 4metals

snoman701 said:


> I used a piece of stainless steel expanded metal as the cathode. The "scrape" in this case need not actually scrape it, just knock off the needles. They then fall to the bottom of the tank. In my case, I wasn't even scraping, just tap tap with a hard metal object.


That sounds like something worthy of consideration. The expanded metal for sure has enough openings to allow the majority of the needles slip through. A good hard mechanical tap every few minutes may clear the screen effectively and it can fall to a sloped ledge to concentrate the scraped needles along the front of cell to be collected with a scoop. There is surely a maximum size that can be cleared with the tapping but finding it may be a matter of trial and error.


----------



## netgeek3

Selling the silver, at volume, isn't a huge problem for us as I have two industrial buyers who are quite interested in buying more than we can provide right now. For us, a good bit of the concern is with the power, but really, once converting to DC, the need for 300A or so is very small compared to typical AC loads for our pulverizers and such. We are working to get our copper line up right now and it is a bit of a power hog, so that certainly has me thinking about the load for this setup. We currently have an 1800A service, but I can expand up to a total of 6MW without having to put together an investment plan for the utility. Cost effectiveness and labor requirements are my number one concern. I love the idea of running 24h/day with just two guys.


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## markscomp

snoman701 said:


> It's minimal cost for silver. Copper the cost of electricity starts to add up.
> 
> It's a lot of current, but a low voltage, so the actual power utilization is small.


go thru numbers based on your amperage in theory and or all costs (theoretical costs include some labor , time to work deals a little, cost of product, electrolites, equpt costs versus returns ) with elect bills and returns - that would help - all would understand that once equipt is in place that the initial cost becomes a repair / replacement cost situation or just maintenance costing


----------



## snoman701

4metals said:


> That sounds like something worthy of consideration. The expanded metal for sure has enough openings to allow the majority of the needles slip through. A good hard mechanical tap every few minutes may clear the screen effectively and it can fall to a sloped ledge to concentrate the scraped needles along the front of cell to be collected with a scoop. There is surely a maximum size that can be cleared with the tapping but finding it may be a matter of trial and error.


Once you know that the crystal can go somewhere, a mechanical scraper like the one you posted will work as well. You don't have to strip it clean, you just have to get it clean enough to make it 12 hours until there's a human to look at it again.


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## Shark

4metals said:


> That sounds like something worthy of consideration. The expanded metal for sure has enough openings to allow the majority of the needles slip through. A good hard mechanical tap every few minutes may clear the screen effectively and it can fall to a sloped ledge to concentrate the scraped needles along the front of cell to be collected with a scoop. There is surely a maximum size that can be cleared with the tapping but finding it may be a matter of trial and error.


It does sound interesting. The cathode scraper could work, a small single hammer type hammer mill could be triggered at intervals to work pretty easy as well. A motor with a plastic pulley and a bar of heavier plastic on a timer to rotate every so often and tap the edge of the cathode. Maybe a way to slow the motor down. Lots of ways could be used to scrape the cathode to some extent.


----------



## 4metals

snoman701 said:


> You don't have to strip it clean, you just have to get it clean enough to make it 12 hours until there's a human to look at it again.


Once the crystals are scraped from a cathode in a thum cell you have about 4 hours before they grow enough to short out the circuit. But if they fall through a cathode of expanded metal they can be collected in a deeper tank. Some cells can run 3 days without scooping out the crystals that have been dislodged from the cathode.


----------



## snoman701

4metals said:


> Once the crystals are scraped from a cathode in a thum cell you have about 4 hours before they grow enough to short out the circuit. But if they fall through a cathode of expanded metal they can be collected in a deeper tank. Some cells can run 3 days without scooping out the crystals that have been dislodged from the cathode.


Right, so if you have a breaker bar that runs on even a 15 minute cycle you should be fine. A timer, solenoid valve and pneumatic cylinder would do this just fine. It wouldn't hurt to do the motor like you posted, but I'd imagine a stainless pneumatic cylinder off ebay has nearly an infinite lifespan running once every 15 minutes. Most refineries will have compressed air to run their filter press.


----------



## Lou

I always pushed the crystal to one end of the Thum cell, then scooped it. They are nice for the butts out of the Moebius. 

For Thum cells I have seen the anode box pulled up and down UHMWPE rails on the Thum cell using two winches that slowly pull it back and forth until a contactor is touched on the anode box and the rail opposite the bus bar on the other end. The effect is a continuous uniform crystal carpet. Those cells are “pushed” every 12 hours into a “goal box” where the crystal is dumped out of it 40-50 lbs at a time. The goal box had a sliding piece of stainless that could effectively dam it such that you could dump the crystal without much loss of electrolyte. The amount of fine crystal is sufficient that a stainless scraper is used and it is pushed not scraped.


----------



## snoman701

Lou said:


> I always pushed the crystal to one end of the Thum cell, then scooped it. They are nice for the butts out of the Moebius.
> 
> For Thum cells I have seen the anode box pulled up and down UHMWPE rails on the Thum cell using two winches that slowly pull it back and forth until a contactor is touched on the anode box and the rail opposite the bus bar on the other end. The effect is a continuous uniform crystal carpet. Those cells are “pushed” every 12 hours into a “goal box” where the crystal is dumped out of it 40-50 lbs at a time. The goal box had a sliding piece of stainless that could effectively dam it such that you could dump the crystal without much loss of electrolyte. The amount of fine crystal is sufficient that a stainless scraper is used and it is pushed not scraped.


Wonder why they dam it as opposed to pushing it into a backet and draining upon lifting.


----------



## Shark

Crystal size most likely would be very small.


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## 4metals

This is just a crude design concept put to paper because if the expanded metal cathode can be made to work, it can be made into a system that eliminates the 4 hour scrapings and simplifies the sucking out of anode slimes in a moebius cell. 


The expanded mesh needs to sit on a lip and will likely have to be framed in PVC to give it rigidity. Also the gauge and the spacing in the expanded metal needs to be experimented with to determine the best cathode to space ratio to maximize silver needle drops when thumped. When the silver drops it hits the angled sheet and slides down into the collection trough. This can be assisted with a pump blowing electrolyte from the upper right of the slope towards the bottom. 

The silver needles can be scooped out daily or after a weekend because they are not (hopefully) accumulating on the expanded metal cathode. 

This design uses an off the shelf PVC tank and the sectioned off space needs to have sheet PVC welded in to make it watertight. The only other welding would be the support ledge for the expanded metal cathode to sit on.

The mechanism for thumping the cathode to break off the siver and allow it to fall through would likely sit on the right end and mechanically lift a weighted rod to rise a few inches and drop onto the cathode, only to be lifted again and drop again continuously. We need to discuss this mechanism more.

Finally, the typical anode basket, which is not detailed here other than a box, could stand some improvement. When insolubles are generated in the anode basket of a Moebius cell, they fall to the bottom where they can be vacuumed out. (easier said than done) On a thum cell there is no place to fall and the mud tends to accumulate and in extreme cases cover the anodes in mud. I am thinking of making a basket to contain the anode bag. In that basket will sit the anode basket which has the anodes spaced 3/4" above the bottom on the support rods. This space will allow the anode slimes to fall. And they will collect in the anode bag below. Routine anode additions will stir up any slimes sitting on the existing anodes and it will settle into the bag as well. Time and experience will determine an effective length of time between anode bag changes and it will vary with the feedstock. But changing the bad is simple, lift out the anode basket, lift and drain the anode bag by allowing the solution to filter through the bag back into the tank, roll up the anode bag (did I mention with long rubber gloves!) and incinerate it to process the slimes. 

This design can serve as a basic starting point, let the discussion begin.


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## Shark

Yamamoto cathode rocker or similar item. I won’t be home until late tonight or sometime tomorrow and and cannot figure out how to copy links from this phone yet.


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## 4metals

Those just push and retract. As per Snowman I think the expanded metal needs a firm hit. I envision lifting a weighted rod and dropping it. I have an idea for a mechanism that may work but my mechanical sketching skills are truly lacking.


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## Shark

They make one that operates both ways. It is tunable to do a smooth up and down or a smooth up with a sudden drop. They also have a speed setting from 0 to 25 times per minutes. I just cannot get the link to work from my phone, pretty sure it’s operator error.


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## Shark

My sketching would be better if my two year old nephew drew it.


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## Shark

Sorry for being gone so long. Here is a video that show both the impact type rocker and a smooth type. 

Rocker video


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## Shark

Not sure if these would handle the weight but would be easy to adapt to to the impact type rocker.






Gear Motor – Flex Coat







flexcoat.com





Edit for spelling.


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## Shark

Motor and gear box for a windshield wiper.


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## 4metals

I think an impactor can be easily made from a slow spinning (1rpm) disc about 6” in diameter with a slit running between a pair of 1/2” holes on opposite sides of the edge connected by a 3/8” slot spanning the diameter. The slow rotating disc has a heavy metal rod with a PVC pipe covering it and a rod sticking out close to the end about 1”. When the disc is spinning the shaft will rise up because the 1/2” hole won’t let it slide freely but is loose enough not to grab it. When it is vertical the weighted pipe will fall the length of the slot and hit the cathode. With the right length it will repeat lifting and dropping continuously. 

The rod sticking through the slot needs to have a washer and a locknut so it doesn’t fall out of the slot or hole but loose enough to drop freely. On the back of the disc a piece of metal shaped like a door handle installed across the slot will allow the nut and washer to slide under freely and centered on the back of the handle is a connection to the drive motor. I use drive motors similar to what Shark posted for a hydroponics drive wheel and have learned, after many failures, to get the model with metal drive gears.


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## Shark

Metal gears would be best for long term use, I would think.


----------



## Palladium

One of the best designs i ever built was a rotating cathode disk with a stainless scraper. 6 anodes in close proximity to one disk with two sides. Hands down!
Stainless disk on a stainless all thread rod. Stainless nuts. Stainless steel scraper blades. Self cleaning. Stainless BBQ grill rotisserie drive. Plastic holding tank. I just wish i had got to keep it! 
This was my mock up for the idea...........


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## Shark

I watched that close for a long time waiting to see how it turned out. I also didn’t want to suggest someone else’s idea, but glad you brought it up.


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## Palladium

Shark said:


> I watched that close for a long time waiting to see how it turned out. I also didn’t want to suggest someone else’s idea, but glad you brought it up.


The turn out part was after this video the client cut me a check! After that came a NDA. 
The proud owner of it i can say is a forum member. If they chose to post it so be it.


----------



## Mudville9

Having recently retired from a rather large precious metals refinery, I feel more at ease in sharing general information developed over the years. Keep in mind that large scale refining is very different from what appears typical sized systems found here. We had the advantage of a fully staffed lab, PLC control of pretty much all aspects of refining, a very competent engineering department etc.
Our Balbac-Thum cells were mothballed 40 years ago in favour of Möbius cells. Nothing can compete with Möbius cells for efficiency, but depending on the design, they can still take appreciable sweat and manpower to operate.
I would be happy to answer any questions on silver (electrolytic or chemical) or gold refining (electrolytic, chemical or chlorination), barring some proprietary information. Yes, we used Wohlwill cells for refining. When you reach a certain level of production, they really are quite efficient. The added bonus is their ability to gather PGM's very efficiently.
As for silver electrolytic cells, I will share a couple of misconceptions I see bandied around in various forums and papers.
The following only applies if you are looking to refine to 99.9% purity. If you want 99.99% purity, or you need to meet ASTM specs, then much greater care of the system is required.
1) Voltage - Many people have definitive limits on what the voltage should be. With well designed Möbius cells, voltage can run much higher that considered "normal". Running at 6 volts per cell is entirely acceptable and I have run much higher during tests.
2) Amperage - Similar to voltage, most literature sets amperage too low. Yes, Balbach-Thum cells generally operate at a low amps per square foot of cathode, but Möbius cells can be run much higher. Sorry for the following units, but you can convert to whatever you wish. Assuming the gold in the silver anode is less than 5%, amperage is typically set to an upper limit of 1000 amps per square meter of cathode area. I have run tests at 2000 amps per square meter and easily achieved 99.9%. Just don't run out of feed during the run!
3) These high current and voltages do raise their own problems. Contacts need to be maintained squeaky clean to prevent overheating, acidification of the electrolyte can be a concern and electrolyte circulation through the cells is required.
4) Copper in solution - Since large refineries accept pretty much all grades of incoming feed, an appreciable amount of material to the silver cells was high copper feed. We would run everything greater than 85% silver through the cells and the copper levels would climb quite rapidly at times. Running up to 120 g/L copper still produced 99.9% purity with 500-600 ppm copper. Perfectly acceptable.

If there are particular questions people have, let me know. I only pop in here once in a while, but I will check back.


----------



## 4metals

Mudville9 said:


> Contacts need to be maintained squeaky clean to prevent overheating.


This is a problem I see often, solution getting hot. It is always an issue of the electrical
contact and always creeps back in to the picture. I always try to get clients to apply dielectric paint once good connections are made or at least dielectric grease to maintain good contacts. 

What, if anything, have you seen used to maintain the contact integrity especially when cranking up the power?


----------



## Mudville9

Again, not likely possible with small scale refining, but a thin (1mm) gold contact brazed to the copper busbars at each connection point works wonders


----------



## 4metals

Thanks for that tip. For a medium to large producer, the labor is the same if you manually harvest 300 or 1500 ounces from each cell and despite the cost of gold invested to improve the contact efficiency, the benefits in production without increased labor would eventually justify it. 

Never heard a silver refiner complain about having to cast more anodes to keep up with cell production.


----------



## Shark

4metals said:


> I always try to get clients to apply dielectric paint once good connections are made


Nice, I have never even heard of dielectric paint, but I have seen many situations where it would have been a big help.


----------



## Shark

Mudville9 said:


> acidification of the electrolyte can be a concern


Would this occur while replenishing the electrolyte or does it occur from the high voltages and amperage's in some way?


----------



## Mudville9

4metals said:


> Thanks for that tip. For a medium to large producer, the labor is the same if you manually harvest 300 or 1500 ounces from each cell and despite the cost of gold invested to improve the contact efficiency, the benefits in production without increased labor would eventually justify it.
> 
> Never heard a silver refiner complain about having to cast more anodes to keep up with cell production.


Melting, casting, cleaning, weighing, assaying, cleaning crucibles, can be surprisingly costly


----------



## Mudville9

Shark said:


> Would this occur while replenishing the electrolyte or does it occur from the high voltages and amperage's in some way?


Not from replenishing the electrolyte, but from daily running of the cells. It depends on the elements contained. High amounts of gold is probably the worst culprit.


----------



## Mudville9

4metals said:


> This is a problem I see often, solution getting hot. It is always an issue of the electrical
> contact and always creeps back in to the picture. I always try to get clients to apply dielectric paint once good connections are made or at least dielectric grease to maintain good contacts.
> 
> What, if anything, have you seen used to maintain the contact integrity especially when cranking up the power?


Poor electrical contacts start fires.
My guess is about 85% of a cells resistance is related to the electrolyte, which heats the solution. High current density likely requires cooling of the solutions.


----------



## 4metals

Mudville9 said:


> Melting, casting, cleaning, weighing, assaying, cleaning crucibles, can be surprisingly costly


Yes but also standard operations for a melt shop. The one thing is the Moebius always requires remelting of anode stubs. That can account for 20% of the anode production. 

Assaying is usually done on large melts as a composite because the bars are all settled and belong to the refiner so a large melt coupled with a stacked mold makes many anodes and fewer assays. 

Care has to be taken not to count the anode stubs as new feed into the system. Especially if they are not logged out as remelt stubs. I had a client do that once, the accountants didn’t know what was logged in and not logged out because it was a remelt and cast not new feed. They thought they had massive losses when they really had poor accounting.


----------



## FrugalRefiner

4metals said:


> FrugalRefiner said:
> 
> 
> 
> A Moebius cell can usually output slightly higher purity.
> 
> 
> 
> I’d like to see some background to that statement. May be true, I haven’t seen it.
Click to expand...


Well, I've spent the last week looking back through my books, and I haven't found it. As I remember, the logic was that with a Thum cell you have crystals growing on top of crystals at all different angles, and in some places they can entrain small amounts of electrolyte with whatever contamination it might carry. Because of this overlapping structure, they are also harder to rinse completely clean. With a Moebius cell, the crystals are constantly being knocked down before this can happen, and they are easier to rinse.

Mudville9, do you have any feedback on this? By the way, it's nice to see you posting again!

Dave


----------



## Mudville9

4metals said:


> Yes but also standard operations for a melt shop. The one thing is the Moebius always requires remelting of anode stubs. That can account for 20% of the anode production.
> 
> Assaying is usually done on large melts as a composite because the bars are all settled and belong to the refiner so a large melt coupled with a stacked mold makes many anodes and fewer assays.
> 
> Care has to be taken not to count the anode stubs as new feed into the system. Especially if they are not logged out as remelt stubs. I had a client do that once, the accountants didn’t know what was logged in and not logged out because it was a remelt and cast not new feed. They thought they had massive losses when they really had poor accounting.


20% stubbage or remelt rate should be at the very top end of the spectrum. It is very much up to the philosophy of the refiner, but with a small amount of extra care and work, stubbage can be reduced to as little as 2.5%. I liked going with the lower remelt rate since all stubs were washed free of any adhering gold slimes and dried before recasting to anodes. Smaller stubs made this washing much easier and faster.


----------



## Mudville9

FrugalRefiner said:


> Well, I've spent the last week looking back through my books, and I haven't found it. As I remember, the logic was that with a Thum cell you have crystals growing on top of crystals at all different angles, and in some places they can entrain small amounts of electrolyte with whatever contamination it might carry. Because of this overlapping structure, they are also harder to rinse completely clean. With a Moebius cell, the crystals are constantly being knocked down before this can happen, and they are easier to rinse.
> 
> Mudville9, do you have any feedback on this? By the way, it's nice to see you posting again!
> 
> Dave


Thanks, nice to be back. 
Retirement frees me from disclosing information that I felt uncomfortable doing while employed. Thum cells produced the most beautiful crystals and I actually found them easier to wash than crystal from Möbius cells. Unless we were producing high purity silver for specific purposes, I wanted the resulting silver crystals to be as close to 99.9% as possible, no free give-away here 
Both set of cells can produce in excess of 99.997% purity, so not sure one is better than the other in that respect.


----------



## orvi

Do you have experience on how high palladium content could be in the anodes, and after electrorefining, what proportion will end up in electrolyte and what proportion goes to the slimes and "fine" silver ? 

I have one feed material that averages around 1% Pd and I try to gain some insight on how it could be effectively refined to obtain pure silver and palladium "something" in the end


----------



## snoman701

orvi said:


> Do you have experience on how high palladium content could be in the anodes, and after electrorefining, what proportion will end up in electrolyte and what proportion goes to the slimes and "fine" silver ?
> 
> I have one feed material that averages around 1% Pd and I try to gain some insight on how it could be effectively refined to obtain pure silver and palladium "something" in the end


Do a literature search. There is a paper that tells you where to keep your maximum electrolyte Pd PPM for minimal dissolution of the Pd anode.


----------



## snoman701

Challenges in the Electrolytic Refining of Silver—Influencing the Co-deposition Through Parameter Control​
Search for that on google


----------



## Mudville9

orvi said:


> Do you have experience on how high palladium content could be in the anodes, and after electrorefining, what proportion will end up in electrolyte and what proportion goes to the slimes and "fine" silver ?
> 
> I have one feed material that averages around 1% Pd and I try to gain some insight on how it could be effectively refined to obtain pure silver and palladium "something" in the end


I hated to have much palladium in silver since we used a common electrolyte distribution system for numerous cells. The distribution tank holds up to 10,000 L so any palladium introduced into a single cell would be spread throughout the system. We used a chemical treatment for waste solutions which was fairly good at recovering PGM's, but even 2 ppm residual palladium in treated solution added up to substantial losses, or at least very difficult to recover values. I know large refiners get mostly a bad rap for PGM payouts, but this is just one of many reasons accountabilities are so low for these elements.
Better for us to add high PGM material to a gold chlorination melt where the resulting material can be put through wohlwill cells where PGM recovery is better.

Recent improvements in ion exchange resins that can stand up to nitrate environments also offers an effective alternative. A Russian refinery has switched to resins and reports keeping PGM's to less than 1 ppm throughout their silver electrolyte.


----------



## 4metals

When Palladium climbs above 50 ppm it will deposit with the Silver as an impurity. I have had great success running electrolyte through a tank to which Dimethylglyoxime is added, which drops the Palladium to be collected in a spiral wound filter tube. 

For smaller refineries without an instrument lab, Dimethylglyoxime is also excellent for quantitative Palladium analysis. When the Palladium content climbs to 30 ppm the electrolyte is treated with Dimethylglyoxime and returned directly to the cells sans Palladium.


----------



## orvi

snoman701 said:


> Challenges in the Electrolytic Refining of Silver—Influencing the Co-deposition Through Parameter Control​
> Search for that on google


Thanks


----------



## diclame

Mudville9 said:


> Running up to 120 g/L copper still produced 99.9% purity with 500-600 ppm copper. Perfectly acceptable.


Do you know the process to precipitate the copper in this solution. To be able to continue using the electrolyte solution back into the silver cells???


----------



## Mudville9

For the most part, it isn't worth trying to regenerate electrolyte. Better to precipitate the silver and dissolve it for fresh solution. There is one very promising route but it is subject to a pending patent and I can't disclose it yet, sorry.


----------



## Shark

This would also come under titration I think. But with decent calculations it may be possible for the cell volume to handle the copper from a known amount of sterling and only need to worry about the copper build up near the end of the week cycle. 

Example: 
The cell would need to be X-gallons to hold Z- ounces of copper. A-ounces of sterling = Z-ounces of copper. On shut down for clean out the silver, the electrolyte would be changed based on the sterling consumption.

I am sure there are other ways to figure this out but that would be a basic way for a simple cell design.


----------



## 4metals

There is some chatter about a method involving heating the electrolyte and raising the pH. Silver Oxide is added to scavenge the base metals. It supposedly will remove the copper and some but not all of the Silver and the Silver Oxide will scavenge the balance of the base metals. The nitric is then replenished and the solution is re-used in the cell. 

In Silver, by Butts & Coxe, they discuss using sodium carbonate to remove copper as a basic salt. 

The description I read was vague and had some errors. I have not yet had an opportunity to get back into the lab and try a few options. It sounds promising but I don’t have a working process yet.


----------



## Mudville9

4metals said:


> There is some chatter about a method involving heating the electrolyte and raising the pH. Silver Oxide is added to scavenge the base metals. It supposedly will remove the copper and some but not all of the Silver and the Silver Oxide will scavenge the balance of the base metals. The nitric is then replenished and the solution is re-used in the cell.
> 
> In Silver, by Butts & Coxe, they discuss using sodium carbonate to remove copper as a basic salt.
> 
> The description I read was vague and had some errors. I have not yet had an opportunity to get back into the lab and try a few options. It sounds promising but I don’t have a working process yet.


The silver oxide works, as does sodium hydroxide and sodium carbonate, but I would only use them for the removal of smaller amounts of copper. Small amounts of copper form an easily filtered copper hydroxide floc, but as more and more copper hydroxide forms, the floc becomes very finely divided, slimy and extremely difficult to filter. I never found a suitable flocculating agent that would allow for easier filtration.


----------



## 4metals

I’ve used the Silver Oxide to clean up silver nitrate solutions for many years. But, as you say, the levels of impurities were low. It is an effective way of making 4 9’s + Silver by treating the dirty Silver Nitrate solution with Silver oxide, filtering, and dropping the Silver as an oxide with high grade sodium hydroxide. The Silver oxides decompose in the furnace and the resultant Silver is high purity. 

I never did push the limits of just how dirty the Silver Nitrate could be and still be effective.


----------



## 4metals

I also have converted the copper nitrate (after cementing out all of the Silver), into copper sulfate and distilled off and collected the nitric for reuse. Then the copper was plated out of the solution to generate clean copper metal. This made the waste product easier to handle as most of the hydroxide forming metals were recovered. I did this for a 30 gallon cell which required changing out of the electrolyte every 4-5 weeks. That allowed me to distill off 5 gallons a week of electrolyte with a 20 liter reactor which made it manageable. 

NurdRage has an excellent video on this method with simple off the shelf equipment and chemical glassware. Commercially, it's a little more challenging only because of scale. 
NurdRage video 

Truthfully all members electrolytically refining Silver have to deal with the copper nitrate waste and we should start a thread in the safety section.


----------



## Lou

I always found Thum cells complimentary to Möebius cells. The stub butt ends could be put into Thum cell. I was at lower voltage of 1.7-1.9 V and maybe 70 A/sf for the vertical vs 3.7-3.9 V and 40-60 A/sf for the horizontal. Problem with Thums is the floor space they take up, but you can always build them up instead of out I suppose.

I have also done titanium anode hooks that go in the mold and can be used to hang the anodes. These conduct better than stainless. If I had an autoclave then, I would have taken the leftover stub and just dissolved in nitric acid/oxygen overpressure because it saves 25% of the nitric used in the best case to dissolve silver and is effectively NOx fume free and 1:1 Ag:HNO3 vs 1:4/3 or more. The Ti hook can be rinsed off and tossed in a drying oven, while the nitric gets the gold and junk filtered out (sent for burning with the bag) while the solution gets used for electrolyte.Some TiO2 ends up in the slimes because the silver eats the titanium by alloying a small amount. Heating the hooks red hot seems to prevent the alloying somewhat without producing too much resistance to current flow.

Insofar as electrolyte is concerned, this is perhaps one area where I had an active interest, both in preparing large volumes of electrolyte with oxygen pressure oxidation (as used at RMC and at OPM) and maintaining it. I certainly agree that concentration, conductivity, impurity profile, temperature and pH are all critical parameters that should be kept as close to steady state as possible. There is not terrible ohmic heating in silver cells if current densities are not so high as mudville describes. Without active cooling/heat exchange, you sacrifice production and a modicum of electrolyte volume management for the crystal rinse waters that get returned after countercurrent wash/decantation. I never had to cool my cells but I have been to facilities where they do.

Now, as to impurities management, I should start by saying that my actual scientific training was in polymer science and for a time I used to make a bit of polymers (i.e. suspension polymerization for ion exchange resins etc.) so I have always had an interest in using these technologies in a silver cell. And they can in fact be used!

I can say that it is almost entirely possible to maintain silver concentrations and copper, nickel, cobalt and palladium in the electrolyte through the use of resins. Zn hopefully is already largely removed during furnacing. Residual elements like Sn and Pb and some Ag as Ag2O typically just end up as their oxides in the anode bag and can be largely blown from the silver if a reverb or TBRC is used up front. The resin itself ignores the silver and binds the Cu and Ni(Co). The preference for which is contingent on pH. Both of these can be eluted with ammonia to regenerate the resin and then NaOH added and the solution boiled to return the ammonia for reuse and give the Ni/Co/Cu as a feed to the copper/nickel refiner. 


I know about that which mudville speaks on the Russian resin but I think people that know just use any weak base anionite resin. I have my own version that I use and like it very much but not in silver duty (though it can be used in a cell and has a very high capacity of about 6 oz Pd/kg of resin in nitric acid conditions and is fully elutable with ammonia water giving [Pd(NH4)4]+2). My opinion on improvements to the best run silver refinery possible is that the converting furnace is a TBRC with removable flue to reprocess the silver mist/condensate. This produces an anode feed that is 98-99% and provides a feedstock slag that can be sent for copper recovery where trace payable silver gets paid back to the refiner. Much of the Cu, Al, W/Mo, Sn, Pb, Sb, Zn and even some Se/Te can be removed. 

These anodes should be cast into tapered molds with a stout titanium hook such that they more or less anodically erode in an even fashion, and the butts can be dissolved for electrolyte makeup, under pressure. I have never liked shot under pressure due but bulk solids behave better. The electrolyte is managed by continuous circulation of electrolyte through resins, the first one to fetch the Pd, the second to fetch Cu. Periodically, the pH is adjusted and Ni/Co can be removed onto the same resin. This resin is still very expensive but price will hopefully go down...


----------



## orvi

Lou said:


> I always found Thum cells complimentary to Möebius cells. The stub butt ends could be put into Thum cell. I was at lower voltage of 1.7-1.9 V and maybe 70 A/sf for the vertical vs 3.7-3.9 V and 40-60 A/sf for the horizontal. Problem with Thums is the floor space they take up, but you can always build them up instead of out I suppose.
> 
> I have also done titanium anode hooks that go in the mold and can be used to hang the anodes. These conduct better than stainless. If I had an autoclave then, I would have taken the leftover stub and just dissolved in nitric acid/oxygen overpressure because it saves 25% of the nitric used in the best case to dissolve silver and is effectively NOx fume free and 1:1 Ag:HNO3 vs 1:4/3 or more. The Ti hook can be rinsed off and tossed in a drying oven, while the nitric gets the gold and junk filtered out (sent for burning with the bag) while the solution gets used for electrolyte.Some TiO2 ends up in the slimes because the silver eats the titanium by alloying a small amount. Heating the hooks red hot seems to prevent the alloying somewhat without producing too much resistance to current flow.
> 
> Insofar as electrolyte is concerned, this is perhaps one area where I had an active interest, both in preparing large volumes of electrolyte with oxygen pressure oxidation (as used at RMC and at OPM) and maintaining it. I certainly agree that concentration, conductivity, impurity profile, temperature and pH are all critical parameters that should be kept as close to steady state as possible. There is not terrible ohmic heating in silver cells if current densities are not so high as mudville describes. Without active cooling/heat exchange, you sacrifice production and a modicum of electrolyte volume management for the crystal rinse waters that get returned after countercurrent wash/decantation. I never had to cool my cells but I have been to facilities where they do.
> 
> Now, as to impurities management, I should start by saying that my actual scientific training was in polymer science and for a time I used to make a bit of polymers (i.e. suspension polymerization for ion exchange resins etc.) so I have always had an interest in using these technologies in a silver cell. And they can in fact be used!
> 
> I can say that it is almost entirely possible to maintain silver concentrations and copper, nickel, cobalt and palladium in the electrolyte through the use of resins. Zn hopefully is already largely removed during furnacing. Residual elements like Sn and Pb and some Ag as Ag2O typically just end up as their oxides in the anode bag and can be largely blown from the silver if a reverb or TBRC is used up front. The resin itself ignores the silver and binds the Cu and Ni(Co). The preference for which is contingent on pH. Both of these can be eluted with ammonia to regenerate the resin and then NaOH added and the solution boiled to return the ammonia for reuse and give the Ni/Co/Cu as a feed to the copper/nickel refiner.
> 
> 
> I know about that which mudville speaks on the Russian resin but I think people that know just use any weak base anionite resin. I have my own version that I use and like it very much but not in silver duty (though it can be used in a cell and has a very high capacity of about 6 oz Pd/kg of resin in nitric acid conditions and is fully elutable with ammonia water giving [Pd(NH4)4]+2). My opinion on improvements to the best run silver refinery possible is that the converting furnace is a TBRC with removable flue to reprocess the silver mist/condensate. This produces an anode feed that is 98-99% and provides a feedstock slag that can be sent for copper recovery where trace payable silver gets paid back to the refiner. Much of the Cu, Al, W/Mo, Sn, Pb, Sb, Zn and even some Se/Te can be removed.
> 
> These anodes should be cast into tapered molds with a stout titanium hook such that they more or less anodically erode in an even fashion, and the butts can be dissolved for electrolyte makeup, under pressure. I have never liked shot under pressure due but bulk solids behave better. The electrolyte is managed by continuous circulation of electrolyte through resins, the first one to fetch the Pd, the second to fetch Cu. Periodically, the pH is adjusted and Ni/Co can be removed onto the same resin. This resin is still very expensive but price will hopefully go down...


High-end technology for metals refining is so fascinating... Saying from old burnt bench with old corroded oxy/propane torch and dirty quartz dish  

Small version of TBRC furnance would make my life so much easier  Now, we need to proceed with our 30kW induction furnance veteran. But small tilting furnance was planned to be built... Thanks for reviving and improving my view about what could be best suited for our use.

As we are now regularly battling quite complex metal mixtures containing PGMs - usually Pb-Sn-Cu-Ag-PGM alloys.


----------



## diclame

the Chinese solved this problem a long time ago and the patent expired so it can be reproduced but I don't know anyone in China who prints the process from the patent office


Mudville9 said:


> For the most part, it isn't worth trying to regenerate electrolyte. Better to precipitate the silver and dissolve it for fresh solution. There is one very promising route but it is subject to a pending patent and I can't disclose it yet, sorry.


----------



## Palladium

Lou said:


> I always found Thum cells complimentary to Möebius cells. The stub butt ends could be put into Thum cell. I was at lower voltage of 1.7-1.9 V and maybe 70 A/sf for the vertical vs 3.7-3.9 V and 40-60 A/sf for the horizontal. Problem with Thums is the floor space they take up, but you can always build them up instead of out I suppose.
> 
> I have also done titanium anode hooks that go in the mold and can be used to hang the anodes. These conduct better than stainless. If I had an autoclave then, I would have taken the leftover stub and just dissolved in nitric acid/oxygen overpressure because it saves 25% of the nitric used in the best case to dissolve silver and is effectively NOx fume free and 1:1 Ag:HNO3 vs 1:4/3 or more. The Ti hook can be rinsed off and tossed in a drying oven, while the nitric gets the gold and junk filtered out (sent for burning with the bag) while the solution gets used for electrolyte.Some TiO2 ends up in the slimes because the silver eats the titanium by alloying a small amount. Heating the hooks red hot seems to prevent the alloying somewhat without producing too much resistance to current flow.
> 
> Insofar as electrolyte is concerned, this is perhaps one area where I had an active interest, both in preparing large volumes of electrolyte with oxygen pressure oxidation (as used at RMC and at OPM) and maintaining it. I certainly agree that concentration, conductivity, impurity profile, temperature and pH are all critical parameters that should be kept as close to steady state as possible. There is not terrible ohmic heating in silver cells if current densities are not so high as mudville describes. Without active cooling/heat exchange, you sacrifice production and a modicum of electrolyte volume management for the crystal rinse waters that get returned after countercurrent wash/decantation. I never had to cool my cells but I have been to facilities where they do.
> 
> Now, as to impurities management, I should start by saying that my actual scientific training was in polymer science and for a time I used to make a bit of polymers (i.e. suspension polymerization for ion exchange resins etc.) so I have always had an interest in using these technologies in a silver cell. And they can in fact be used!
> 
> I can say that it is almost entirely possible to maintain silver concentrations and copper, nickel, cobalt and palladium in the electrolyte through the use of resins. Zn hopefully is already largely removed during furnacing. Residual elements like Sn and Pb and some Ag as Ag2O typically just end up as their oxides in the anode bag and can be largely blown from the silver if a reverb or TBRC is used up front. The resin itself ignores the silver and binds the Cu and Ni(Co). The preference for which is contingent on pH. Both of these can be eluted with ammonia to regenerate the resin and then NaOH added and the solution boiled to return the ammonia for reuse and give the Ni/Co/Cu as a feed to the copper/nickel refiner.
> 
> 
> I know about that which mudville speaks on the Russian resin but I think people that know just use any weak base anionite resin. I have my own version that I use and like it very much but not in silver duty (though it can be used in a cell and has a very high capacity of about 6 oz Pd/kg of resin in nitric acid conditions and is fully elutable with ammonia water giving [Pd(NH4)4]+2). My opinion on improvements to the best run silver refinery possible is that the converting furnace is a TBRC with removable flue to reprocess the silver mist/condensate. This produces an anode feed that is 98-99% and provides a feedstock slag that can be sent for copper recovery where trace payable silver gets paid back to the refiner. Much of the Cu, Al, W/Mo, Sn, Pb, Sb, Zn and even some Se/Te can be removed.
> 
> These anodes should be cast into tapered molds with a stout titanium hook such that they more or less anodically erode in an even fashion, and the butts can be dissolved for electrolyte makeup, under pressure. I have never liked shot under pressure due but bulk solids behave better. The electrolyte is managed by continuous circulation of electrolyte through resins, the first one to fetch the Pd, the second to fetch Cu. Periodically, the pH is adjusted and Ni/Co can be removed onto the same resin. This resin is still very expensive but price will hopefully go down...


Would Bipolar membranes have a place in any of this Lou?


----------



## Lou

Alas, they do not remove impurities well enough compared to resins.

I've used them before. They're nice for cationic metathesis (i.e. turning NaNO3 to HNO3 and NaOH) but are power hogs, have fragile membranes, and require, at least in some instances, those nasty expensive iridium oxide coated titanium anodes.


----------



## Palladium

I looked at using them before to make a small machine for producing nitric acid for those people who can't buy or find it. I have several 24 x 24 sample pieces manufactures have sent me.


----------



## Shark

Where are we at for a power supply?


----------



## 4metals

This thread is going in many directions, all of them good, but difficult to follow. What I wanted to do is open a poll to ask a few questions and decide where to take this thread and if necessary start new threads accordingly. But the polling function on this software has to be activated by the new admin, and when it is, a poll will appear here so we can all participate and move in the proper direction.


----------



## 4metals

The poll in the software only supports 1 question so I cobbled this together and I will tally the results. Instructions on how to post answers are at the end.

*1. Is the style of the cell, Thum or Moebius, important or is the production capacity the determining factor?*
a. I prefer a Moebius Cell
b. I prefer a Thum Cell
c. I only care about production capacity.

*2. As far as production capacity of a silver cell what is a preferred weekly production rate?*
a. 100 OZT a week
b. 500 OZT a week
c. 1000 OZT a week
d. 3000 OZT a week
e. > 3000 OZT a week

*3. Ability to fabricate the cell.*
a. I need to have a cell I can fabricate with common tools and few specialized skills.
b. I would be willing to have a specialist come in to help with fabrication.

*4. What additional topics do you want to see to cover the refining of silver.*
a. Making electrolyte
b. Casting anodes
c. Analysis of a silver cell to keep it running
d. Treating the waste from a silver cell
e. Operating a break down cell to recover silver from lower grades of scrap
f. Processing anode slimes
g. Let’s discuss it all, in separate threads

*How to answer this survey*
If I am interested in a thum cell for question 1 answer *1,b*

If I want to produce 1000 oz a week as asked in question 2 answer *2,c*

If I want to build this myself with no specialized skills (like PVC welding) in answer to question 3 answer *3,a*

And if I do not know any of the techniques involved the answer to question 4 but want to see my options, my answer would be, *4,g*

If I missed any questions please let me know and I can add to the list.


----------



## Shark

1: Personally, I prefer the bigger refiners decide that. The bigger refiner is what I would like to see a glimpse into as they grow. (Although I would like to see how that extruded cathode would work out.)

2:Refer to #1.

3:B
I can weld plastic, but if not an auto body shop should be able to do it. Our local tech school is always looking for projects to work on and it does teach plastic welding.

4:G

We have a means to see some great stuff here, lets see some votes.


----------



## snoman701

orvi said:


> Small version of TBRC furnance would make my life so much easier  Now, we need to proceed with our 30kW induction furnance veteran. But small tilting furnance was planned to be built... Thanks for reviving and improving my view about what could be best suited for our use.


Absolutely! I started building one that I could prove out with a 10lb melt until I realized that while I could comfortably get the lot molten, dealing with the exhaust is another story entirely for a guy in his garage. Lead and Zinc will both recondense quite well, but you still have to deal with hot gasses that need to be cooled before they can be filtered.

As for the cell. My interest is a cell that is readily available from parts, 100-500 oz / wk and being able to treat the waste is really important. 

Breakdown cells are cool too.


----------



## netgeek3

Poll answers:
1,c - production is what I care about
2,b or c anywhere in this range works
3,b
4,g - I think it would be good to properly explore all of these and the options available


----------



## 4metals

Since it's been a week with no more input and the response was quite underwhelming, I am going to pick a number of 1000 oz a week to explore. That's about 31 kg a week or 4.4 kg per 24 hour day. A satisfying quantity of Silver to harvest every morning for a small refiner. 

If no-one complains about the, quantity of production I'll start tomorrow with the calculations for this size.


----------



## FrugalRefiner

You may not hear from me, but I'll be lurking and taking notes the whole way.

Dave


----------



## grainsofgold

what’s the best design for a thum cell - round steel tank or the traditional rectangular one we see a lot off ?

In regards to the power supply - is there a type which is better than others to use and what voltage and amp specs are ideal ? 

Thanks. 

GOG.


----------



## Abdoulapapatte

I find this post very interesting, apparently on the same problem



Hello friends I would like to introduce myself in a few words: I am 33 years old passionate about metals I intend to become a professional in the circles, I want to be a tester later refiner.



some pictures of what I'm already doing.

Note that my cell consists of a stainless steel pot for the negative cathode.



here a small pretty collection of silver 999/1000 5 (SPECTRO 3SEC)



behind here are more pictures of the money.



I specify here that my cell must be in 8 liters.







For the anode, I use a plastic container, and dacron as a particle filter, to avoid disturbing my electrolyte. for the power supply I simply used an old computer power supply, I run at 3.5v, no memory for the amperage.



I tried other voltage 5.5 volt, 12 volt, I notice 2



1) I feel like but crystals form faster with higher voltage V (and I imagine the intensity increased too)


2) the higher the voltage, the more I actually have a small anarchic dendrite, which sometimes short-circuits my cell

all this works very well sometimes by analyzing the spectrometer I come across 999,

Last time I tried to come away with 850/1000 title money. the result was similar, I still noticed more anodiac mud than usual and faster blue/green saturation








you will therefore have understood that I am not a professional but rather a confirmed amateur.



for me for a few kg per month.



today I have a person who came to see me and offered to leave me 10 kg per week to start then to go to 20 kg.



So I ask you the question, is it possible? how would you see the cell?

do you have any idea of the ideal cell size? of its shape?
what type of thumb/moebius cell?

tomorrow I will select bins I will take a picture of them to possibly have the consent of certain groups on the subject.

I mark you in bold the questions that I ask myself, please I ask you for answers I need help

I specify that I intend to start with an 80 liter cell of rectangular shape in pehd or pp plastic. I intend to line this 80 L plastic rectangle with a 2 or 3 mm stainless steel sheet.

I also plan to put vertical cathodes every 30 cm to increase the cathodic surface.

For the anode it will be Ag shot already treated with nitric and reduced on copper.

*
1) I heard on some forums that the maximum voltage was 3.8 volts above the risk of copper deposit if present (in my case very often Ag/Cu alloy). do you confirm this phenomenon?
what is the best voltage to work I read in the discussion that some pass in 6 volt without problem


2) if it is necessary to work efficiently with a low tension, in this case I suppose that it is the intensity I(A) which will play an important role in the formation of the crystals? what intensity do you recommend?


3) how can I quantify copper in solution without using spectrometry?


4) do you have an idea of the material that I should use for this scale, namely to do 20 kg / week
for a first start I would be happy with already 10 kg


5) is there a physical law to calculate the desired quantity of matter according to the intensity of the cell's litration voltage, the mass concentration, the anode/cathode exchange surface?


6) in the end with what purity can we start the electrolysis to have a cathode listed at 999?


7) I have never calculated the resistance of my cell, how can I proceed?


8) What power supply do you recommend, what device to deliver direct current?
what type of block max voltage max amperage


9) Do we agree that the bigger the cell, the more deposits, or does size have nothing to do with it?


thank you for answering my questions by telling me 1) 2) 3) for those who know of course thank you*


----------



## Yggdrasil

Abdoulapapatte said:


> Je trouve ce post très intéressant, apparemment sur le même problème
> 
> Bonjour les amis je voudrais me présenter en quelques mots : j'ai 33 ans passionné par les métaux je compte devenir professionnel dans les milieux , je souhaite être testeur plus tard affineur .
> 
> quelques photos de ce que je fais déjà.
> A noté que ma cellule est constituée d'une marmite en inox pour la cathode négative.
> View attachment 52218
> 
> 
> ici une petite jolie collection d'argent 999/1000 5 (SPECTRO 3SEC)
> 
> derrière voici d'autres photos de l'argent.
> 
> Je précise ici que ma cellule doit être en 8 litres.
> 
> 
> 
> Pour l'anode, j'utilise un récipient en plastique, et du dacron comme filtre à particules, pour éviter de troubler mon électrolyte. pour l'alim j'ai simplement utilisé une ancienne alim d'ordinateur, je tourne en 3.5v pas de mémoire pour l'ampérage.
> 
> j'ai essayé d'autre tension 5,5 volt, 12 volt, j'en remarque 2
> 
> 1) J'ai l'impression que mais les cristaux se forment plus vite avec une tension V plus élevée
> 
> (et j'imagine que l'intensité a augmenté aussi)
> 
> 2) plus la tension est élevée, plus j'ai effectivement une petite dendrite anarchique, qui parfois court-circuite ma cellule
> 
> 
> tout cela marche très bien parfois en analysant le spectromètre je tombe sur 999,
> 
> La dernière fois, j'ai essayé de repartir avec 850/1000 d'argent de titre. le résultat était similaire, j'ai quand même remarqué plus de boue anodiac que d'habitude et une saturation bleu/vert plus rapide
> 
> 
> 
> View attachment 52219
> View attachment 52220
> View attachment 52221
> View attachment 52222
> 
> vous aurez donc compris que je ne suis pas un professionnel mais plutôt un amateur confirmé.
> 
> pour moi pour quelques kg par mois.
> 
> aujourd'hui j'ai une personne qui est venue me voir et m'a proposé de me laisser 10 kg par semaine pour commencer puis de passer à 20 kg.
> 
> Alors je vous pose la question, est-ce possible ? comment verriez-vous la cellule?
> 
> avez-vous une idée de
> 
> la taille de cellule idéale ?
> 
> de sa forme ?
> 
> quel type de cellule pouce/moebius?
> 
> demain je sélectionnerai des bacs je les prendrai en photo pour éventuellement avoir l'assentiment de certains groupes sur le sujet
> 
> Je vous marque en gras les questions que je me pose, s'il vous plait je vous demande des réponses j'ai besoin d'aide
> 
> Je précise que je compte commencer par une cellule de 80 litres de forme rectangulaire en plastique pehd ou pp. Je compte doubler ce rectangle plastique de 80 L avec une tôle inox de 2 ou 3 mm.
> 
> J'envisage aussi de mettre des cathodes verticales tous les 30 cm pour augmenter la surface cathodique.
> 
> Pour l'anode ce sera de la grenaille Ag déjà traitée au nitrique et réduite sur cuivre.
> 
> 
> *1) J'ai entendu sur certains forum que la tension maximale était de 3,8 volts au dessus du risque de dépôt de cuivre si présent (dans mon cas très souvent alliage Ag/Cu). confirmez-vous ce phénomène?
> 
> quelle est la meilleure tension pour travailler j'ai lu dans la discussion que certains passent en 6 volt sans problème
> 
> 
> 
> 2) s'il faut travailler efficacement avec une basse tension, dans ce cas je suppose que c'est l'intensité I(A) qui va jouer un rôle important dans la formation des cristaux ? quelle intensité recommandez-vous?
> 
> 
> 
> 3) comment puis-je quantifier le cuivre en solution sans utiliser la spectrométrie ?
> 
> 
> 
> 4) avez-vous une idée du matériel que je dois utiliser pour cette balance, à savoir faire 20 kg/semaine
> pour un premier debut je serais content avec deja 10 kg
> 
> 
> 
> 5) existe-t-il une loi physique pour calculer la quantité de matière souhaitée en fonction de l'intensité de la tension de litration de la cellule, de la concentration massique, de la surface d'échange anode/cathode ?
> 
> 
> 
> 6) au final avec quelle pureté peut-on démarrer l'électrolyse pour avoir une cathode cotée de 999 ?
> 
> 
> 7) Je n'ai jamais calculé la résistance de ma cellule, comment puis-je procéder ?
> 
> 
> 8) Quelle alimentation préconisez-vous, quel appareil pour délivrer du courant continu ?
> quel type de bloc tension max ampérage max
> 
> 
> 9) Sommes-nous d'accord que plus la cellule est grande, plus il y a de dépôts, ou la taille n'a-t-elle rien à voir avec cela ?*
> 
> 
> merci de répondre à mes questions en me disant 1) 2) 3) pour ceux qui connaissent bien sur merci


Dette har vi gjort før ikke sant?
Hvorfor fortsetter du å poste på Fransk?

Edit to add: 
And then you change it to English without marking it as edited?
Thanks for that, but you should give notice that it is edited.


----------



## snoman701

4metals said:


> Since it's been a week with no more input and the response was quite underwhelming, I am going to pick a number of 1000 oz a week to explore. That's about 31 kg a week or 4.4 kg per 24 hour day. A satisfying quantity of Silver to harvest every morning for a small refiner.
> 
> If no-one complains about the, quantity of production I'll start tomorrow with the calculations for this size.



I will be looking forward to your response.

Do you keep track of the contamination in your electrolyte simply by keeping track of the feedstock, or through titrations of the electrolyte?


----------



## Mudville9

I am (hopefully) attaching a spreadsheet that you can modify and play around with. It is a simplified set of calculations that can be used to determine outputs versus inputs.
A few things to keep in mind.
1) Any fields in yellow can be changed and will affect all other calculations.
2) This system is based on a 350 L möbius cell, with some extra electrolyte for recirculation. Feel free to change the electrolyte amount to whatever you want.
3) This is a simplified sheet, one of many that I used to calculate resources and costs for various types of feed.
4) Since this is an industrial sized system, it might not have a lot of use for hobbyists, but play with it and modify it to fit your needs.
It is hardly a perfect set of calculations, but it served its purpose


----------



## Abdoulapapatte

I can't open your document too bad


----------



## Abdoulapapatte

finding a tank of more than 300 liters is starting to become difficult and I imagine that it must take up space, in your opinion what should be the size of a cell to already reach 20 kg per week.
I was asking if there was a possibility that nitric acid would eat away at the stainless steel of my cell, I think I'll line the next one with plastic
better to be careful
if someone can explain to me in the end the maximum in voltage and amperage to maintain the purity at 999 and the fastest way to get there, because let's not forget that the time factor is also important
thank you


----------



## Abdoulapapatte

Yggdrasil said:


> Dette har vi gjort før ikke sant?
> Hvorfor fortsetter du å poste på Fransk?
> 
> Edit to add:
> And then you change it to English without marking it as edited?
> Thanks for that, but you should give notice that it is edited.


I write in English translated on google map but gogle translates everything into French on the forums and changes from English to French without being asked about reporting the translation, sorry but I don't understand what it's for j I simply rewrote the text in English.


----------



## Yggdrasil

Abdoulapapatte said:


> I write in English translated on google map but gogle translates everything into French on the forums and changes from English to French without being asked about reporting the translation, sorry but I don't understand what it's for j I simply rewrote the text in English.


Yes and that is fine, but you should write a remark that it is edited, so the replies made still will make sense.


----------



## Shark

Any updates?


----------



## Lou

It's only been two weeks, give 4metals some time and he will be back.


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## Abdoulapapatte

Hello everyone, your project excites me and in the end I decided to build myself, a silver cell 145 liter a little bigger than the one usually used I have already designed a little plan and I'll show you where I want to go. for my part the quantities you give are too big I can go to 100 kg max per month, I will make a prototype then improve it

picture arecoming


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## Abdoulapapatte

Hello I see that time has passed since April and we still have no response from formetal I would like to know if this post is dead or if it will continue to live because I found it very interesting.
It would be good if we continued to make this position live because I think that money is a very interesting area in the field of economic and I really find it more interesting than from an economic point of view for foundry refiner testers.
My personal goal arrived at 100 kilos per month of silver refine each month with the simplest and most economical means which could also run without production of nox or as little as possible because I have not yet created my chemistry hood I would like to leave the small street chip style electrolysis and its predecessors I would really like to arrive on something professional and without forgetting safety


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## Abdoulapapatte

I would be curious and I tell myself that it could be good to all be able to compare the equipment we are currently using and the performance that it generates, comparing our installations and our results between us will be good for all, I think. I await your feedback thank you.


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## Yggdrasil

Abdoulapapatte said:


> Hello I see that time has passed since April and we still have no response from formetal I would like to know if this post is dead or if it will continue to live because I found it very interesting.
> It would be good if we continued to make this position live because I think that money is a very interesting area in the field of swimming girls and I really find it more interesting than from an economic point of view for foundry refiner testers.
> My personal goal arrived at 100 kilos per month of silver refine each month with the simplest and most economical means which could also run without production of nox or as little as possible because I have not yet created my chemistry hood I would like to leave the small street chip style electrolysis and its predecessors I would really like to arrive on something professional and without forgetting safety


Please can you edit your thread.
I expect the swimming girls is a translation error?
I for one do not want swimming girls in my electrolyte.


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## Abdoulapapatte

I do thx


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## FrugalRefiner

4metals hasn't had much time to spend here recently. His wife had a knee replacement and he has been spending a lot of his time taking care of her.

He will be back again, and perhaps we can revive this thread.

Dave


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