Cost to refine silver braze (50% Ag) - Advice appreciated

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anachronism said:
Lou

I'm pretty sure that Chris knows things have changed since the 70s. Edit: He also has an incredible knack of explaining things in a manner that will be understood by the average man jack refiner.

This thread is one of a long line of threads asking technical details from the same author who as much as I like him would be best served nailing the basics and getting some results.
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Understood, Jon. Mind you, I think Chris's book is one of the most accessible bits of practical refining ever written. Everyone here knows I wax theoretical and long-winded at best.

I agree it is easy to dissolve in 50/50 nitric/DI water, filter and cement, or even convert the chloride with sulfuric and nails.

Guess I'm just saying that if one does 100 lbs of CuAgZnNi braze with nitric then it's a legitimate concern over being legal and not contributing to poor air quality. One is addressed by taking more time, the other by pollution control.


I've done my share of stupid. GSP was there for some of it!
 
Lou

VERY interesting read you have posted in this thread 8)

It is a bit (ok - a lot) beyond me - but very interesting none the less

Thanks for posting 8) :!:

Kurt
 
This post assumes that Lou's figures of 10# of NO2 can be legally exhausted into the air in a 24 hour period are correct. I wonder if there are any state regs that would lower those amounts? CA, maybe?

In order to not exceed the exhaust of 10# of NO2 over a 24 hour period, let's see how much 70% nitric acid you could legally consume during that period. If you search for the chemical equations involved with dissolving copper or silver in nitric, you will find several different ones. For example, with weak nitric, you will find that the nitric is more efficient (dissolves more metal) than with strong nitric. For this discussion let's assume the worst case, in which exactly half of the nitric used will go into the production of NO2.

One Mole (M) of NO2 weighs 46g. Therefore,10# of NO2 = (10 x 454)/46 = 98.7M

One M of HNO3 weighs 63g. One liter of 70% HNO3 contains 989g of HNO3. Therefore, one liter of 70% HNO3 contains 989/63 = 15.7M of HNO3. Therefore, one gallon of 70% HNO3 contains 15.7 X 3.785 = 59.4M of HNO3.

Since the number of M's of HNO3 needed to produce 98.7M of NO2 is equal to the same number of M's of HNO3, it would take 98.7/59.4 = 1.66 gallons of 70% HNO3 to produce 10# of NO2, assuming all of the HNO3 used went into the production of NO2.

However, in the worst case only half of the HNO3 used is converted to NO2. The other half produces the NO3- needed to combine with the dissolved Cu++ and Ag+.

Therefore, in the worst case, you could legally consume 2 X 1.66 = 3.32 gallons of 70% HNO3 per 24 hour day.

In the worst case, it would take 33 gallons of 70% HNO3 to dissolve 100# of the 50/50, silver/base metal mix. Therefore, in the worst case, it would take 10 days to legally (by Federal law) dissolve 100# in an open top container, in a fume hood with no scrubber. I could live with that.

Since anyone doing this would surely buy nitric by the drum, the savings would be minimal using pressure. I would think the quantity of waste would be the same.

I'm not advocating that anyone not use a scrubber. For most of my working life, I've used a scrubber, but there were a few exceptions, especially early on in my career. The EPA didn't start cracking down on this industry until the mid-70s. By then, I had been doing this for 10 years.

Am I missing something?
 
That IS a lot of nitric!

For me anyways.
I bought mine in 2.5L bottles (4 of them)
Have had them about 6 months and still have a couple Liters

3.32 gallons is 12.57L (rounded up)
So, it takes me more than half a year to get to that daily limit.
...talk about small fish in a big pond
 
goldsilverpro said:
Am I missing something?
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I don't think so. You're staying practical, and that's not a bad thing at all.

Lou stated the scale of the digestions....100 k oz. Note the k. That's a heckuvalotta silver.

For I'm sure most of us here, using a bomb for this would be an exercise in overkill....if not an exercise in making a literal bomb.

BUT...people who are refining precious metals as a hobby, aren't exactly right in the head to begin with. At least in comparison to the general populous. I mean, I fish...on occasion. I'll garden this summer. And I love my animals. Beyond that, I'm strange. I have a machine shop. I automate stuff for fun. I like to play with high voltage. I spend $10 to make something that I can buy for $5. Practical, I rarely am. I have been referred to as the mad scientist by my wifes family since day one. At least this lab product produces something they can understand.

It's like Lou said, "he asked, so I answered". Being the geek that I am, I got excited. In fact, I want to read the 40 page paper!

But, it's like your posts about your work with intel. I get curious...what did the deplating rack look like? Gotta be fast to load, but still apply a very small force to each pin to maintain an electrical conductivity. How long did it take to prep each chip?

Then I start to wonder...how is the ceramic prepped for the gold braze? And the silica die? Wettability is incredibly important.

Now i need to take a break for a couple days...I need to work on making a profit for a bit, so I can expand my organization....but first...organizing, and cleaning...probably in the opposite order than what I listed them. But I think it's spring...SPRING!

edited for bad spelling
 
The 10 pound limit Lou is speaking about is the de-minimus status and for a business generally the rule is a daily limit which you need to be under and you can get away without fume scrubbing. But there is a catch, there always seems to be a catch, and the catch is if no one complains. That means if you have a neighbor who see's the red cloud or smells the fume and turns you in, all bets are off and you need to scrub the fume. In some states it is even more liberal and the total is an annual total. So if you are in the middle of nowhere where you will not upset any onlookers and in Indiana, where the total is annual, you can do 50 pounds in a day and nothing for a week and still be compliant. So some states are much easier to be permitted than others.

I do agree with Lou that for a specific digestion process there is a potential to save in both overhead, setup costs, and efficiency by using pressure can be of a benefit to a refiner. But, and there is often a but (just like there is always a catch) Chris's calculations are spot on and the quantities of nitric dissolution one can accomplish and be under the de minimus status are substantial.

The type of refining operations I set up rarely can count on a specific feedstock, most have their "target" refining goals and look to refine what they do best. This usually means you cannot count on being under the de-minimus status so they require a scrubber. A properly operated fume scrubber operating according to it's design specifications operates in the 99% efficiency range. This means that you can utilize more like 1000 pounds a day of nitric (about 100 gallons) and still be under the reportable quantities because they measure what you discharge not what you treat. So a scrubber can give you huge versatility.

What all of this means is that Lou is absolutely correct, except there are few chemists running around today in refineries with his background to use the types of equipment he talks about. I will also say Chris is also absolutely correct in his preference of the KISS technology in refining because it speaks to most of the smaller and medium sized refiners out there. So it comes down to using a high tech method and praying you get enough work to justify the investment in the equipment, training and increased safety requirements, or choosing a less technical method and spending your capital on versatility (by buying a good scrubber) or not, and squeaking under the de minimus wire.

Today I see more opting for versatility and occasional squeaking under the wire than the high tech options. But here on the GRF we get the benefit of discussing both. And that's pretty awesome in it's own right!
 
Topher_osAUrus said:
snoman701 said:
BUT...people who are refining precious metals as a hobby, aren't exactly right in the head to begin with....
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HEY! I... ..well, no .... I guess that's about right :twisted:
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I would take umbrage to that, but it's hard to when it's so, uhm, accurate. :oops:
 
So is anyone able to shed a little light as to what they would charge to refine something like this? This is really still my biggest concern.
 
Why? That's down to you. You know what it's going to cost in materials and what it's going to cost in your time. Work out what you want to make from the job and crack on.
 
I know that refiners who were used to doing chemical stone removal charged a percentage of the gold, so the average 100 ounce 14 karat lot netted them about $700 at a 1% refining charge. Then along came silver stone removal when the price of gold got so high and manufacturers switched to silver, so most just decided on a number they had to make per lot, based on time and materials, and worked it into a percentage.
 
anachronism said:
Why? That's down to you. You know what it's going to cost in materials and what it's going to cost in your time. Work out what you want to make from the job and crack on.
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In machining/fabrication/engineering/repair work, my charge is $100 / hr with a $50/hr travel charge, port to port.......BUT....I know that I am competitive with other companies.

Refining is a new world for me.

Then this is also a company that I have extensive dealings with already...they'll likely take what I offer, as long as it sounds reasonable. BUT...If they can send it up the road and get 80% from a company with a good reputation and I can only do the work for 65%, my business philosophy is that I refer them....it pays dividends down the road.
 
If you're saying that if you know someone who can do it cheaper than you, that you will refer them to that person then your business philosophy will not make you any money.

I take 25% for everything and always get it because plenty of people have had experience of the 10% boys who strangely only ever return the clients smaller yields. An honest 25% beats a dishonest 10% hands down. if you're doing a job for someone then your time has to be adequately paid for, other wise you may as well do a couple of shifts down at Walmart and not bother with the mess.

Jon
 
No...I'm saying exactly what you just said! It's the net of their experience. I used to work in private veterinary practice at the referral level. We provided the same care the university did at 1.5x the price. I told customers that if they complained about the cost. I told them they were paying for service. I told them they were paying for the ability to talk to a doctor at 2am when they were concerned about Fluffy, not a student that has to ask a tech that has to ask a resident that won't comment because they don't know what the fellow plans to do.

I know that as of now the statement "we didn't meet their minimums and the base and hidden costs were really high" was thrown out there.

My business philosophy is simple. Be honest about your capabilities, do what you say you are going to do, when you say you are going to do it and finally, charge a fair price. I find in business, MOST professional companies fail on at least one of those aspects. The price is very dependent on the service provided.

At the same time, even a simple referral is not so simple. Given the perceived experience when selling PM's, I'd think long and hard before I referred anyone anywhere. Everyone wants to be able to walk in to the jewelers, get 200-300% of melt, in small unmarked bills. Anything else and the customer is clearly being robbed!!! (complete sarcasm)
 
snoman701 said:
... Everyone wants to be able to walk in to the jewelers, get 200-300% of melt, in small unmarked bills. Anything else and the customer is clearly being robbed!!! (complete sarcasm)
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Sarcasm maybe...but, sadly there are a lot of people that DO expect retail (spot + premium + benchman labor +business overhead).. Probably more of "those people" now than the people who know absolutely nothing and accept the ridiculously small offers the pawn shops put forth.

A lady the other day called me and wanted to sell me a 14k white gold ring and bracelet. Together weighed 11 grams. I made my offer, and she scoffed and said she was wanting closer to 3 grand.
...well then...
Pass! Good day to you Miss...
 
I hear you Snoman.

I do agree that there are a lot of folks out there who expect the highest price when they are selling and very often they are the ones driving the hard bargain when buying.

They are usually the ones who don't have the ready supply, and think to make as much as possible on the rare deals. Then again if they took a slightly different approach they'd get both more suppliers and more buyers. :D

The old Jewish adage of "leave something in for the next person" really does apply 8)
 
Do you expect to bring this up to a purity of .999 fine or are you going to be happy to cement out the silver and sell it as is? Everything you do to increase the purity comes at a cost. If you need to earn $100 an hour you need to estimate the time you will put into this. A digestion is more elapsed time than time spent, and if you're fair (meaning you want to come up to the actual amount of your physical time) Getting the silver to cement purity isn't really that much time spent either.

But let's set the silver value at $17.00. So every hour you spend refining this you need to charge 5.9 ounces. First come up with a reasonable quantity you can process per lot. For argument sake lets call that 25 pounds. That comes to 364.6 ounces incoming. The assay, which needs to be verified by yield, is stated at 50%. So the job will yield 182.3 ounces. If the entire process, start to finish takes 6 hours of your actual time spent, which is reasonable for little stuff you will have to do along the way, but for argument sake say 6 hours. So 6 times 5.9 ounces per hour means you need to retain 35.4 ounces to make up your $100 an hour. That makes your labor charge 19.4%. You still have to calculate chemical costs and waste treatment costs and any fixed overhead.

I'm guessing you will end up around 30% to cover your recovery costs for cemented silver. This price means your customer takes back the cement silver either as bars or shot because if you have to sell it you need to figure in how much that will cost you.
 
Topher_osAUrus said:
snoman701 said:
... Everyone wants to be able to walk in to the jewelers, get 200-300% of melt, in small unmarked bills. Anything else and the customer is clearly being robbed!!! (complete sarcasm)
Click to expand...

Sarcasm maybe...but, sadly there are a lot of people that DO expect retail (spot + premium + benchman labor +business overhead).. Probably more of "those people" now than the people who know absolutely nothing and accept the ridiculously small offers the pawn shops put forth.

A lady the other day called me and wanted to sell me a 14k white gold ring and bracelet. Together weighed 11 grams. I made my offer, and she scoffed and said she was wanting closer to 3 grand.
...well then...
Pass! Good day to you Miss...
Click to expand...

I see it from both sides. On occasion, those pieces where someone WAS robbed at 70% of melt...but in those cases, the buyer has the opportunity to say no.

I've tried buying jewelry for it's rarity or collectibility....lost on every single piece. I obviously have no understanding of that market. So...I'll just tell people I'll buy on metal value only.

I spent the better part of my adolescence at antique shows with my parents. I've been buying and selling for years. I'm used to people who think I'm ripping them off, but know that it's a fair number of sellers.
 

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