# Process Questions



## ffbsm85 (Feb 2, 2012)

Hey everyone! I just recently started doing a lot of research on silver refining and I'd like to start doing it! I'm working on a process "cheat sheet" and I really want to be 100% sure I know exactly what is going on with every step. I have a few questions:

1. The Nitric Acid you use should be about 30-35%? As in half 70% acid half distilled water?
2. Is this the right process? 
- Add acid to silver (more then ~40% purity)
- FUMES BAD
- Let all acid evaporate out (not sure on this part)
- Dilute nitrate solution to 50% with distilled water
- Filter solution
- Add clean copper to cement silver
3. What do you do with the left over solution?


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## publius (Feb 2, 2012)

Not exactly correct...
Depending on the purity of the silver one could go to electrolytic refining or wet chemical recovery then to additional refining steps.

If the feed stock is less than 96-97% silver follow this:
Digest in Nitric acid
Filter
Precipitate with salt (sodium chloride (NaCl)) to form silver chloride.
Filter
Wash-wash-wash the silver chloride.
Cement silver chloride with dilute sulfuric acid and iron (copper, aluminum or zinc)
Filter
Wash-wash-wash cement silver with very dilute sulfuric acid to remove and tramp base metals.
dry
Melt into dore bar and move onto electrolytic refining.

Edited to correct fat finger mistake.


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## ffbsm85 (Feb 2, 2012)

I'd rather avoid having to go the silver chloride route if at all possible. Are you saying that 97% and below silver needs to follow that process?


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## Geo (Feb 2, 2012)

publius said:


> Not exactly correct...
> Depending on the purity of the silver one could go to electrolytic refining or wet chemical recovery then to additional refining steps.
> 
> If the feed stock is less than 97-97% silver follow this:
> ...



actually thats more complicated than it should be. dissolve the silver in dilute nitric (70% nitric acid) 50/50 water to acid. cement with clean copper until no more copper goes into solution. rinse cemented silver in water until water stays clear. filter and dry. cast into anode bars for silver cell to make pure silver or sell cemented silver bars as is at about 98% pure.


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## philddreamer (Feb 2, 2012)

I also prefer to avoid the Ag/Cl & the extra steps involved & supplies needed to acomplish what cementing with copper does in a fraction of the time.

Incinerate your silver scrap.
Digest silver in 50/50 distilled water/ nitric
Filter
Cement with clean copper
Rinse
Melt into anodes (.99 fine)
Process thru a silver cell (.999 fine)

The "cleaner" the silver is before processed thru the silver cell, the longer the life of the silver nitrate & the less nitric needed over all.

There're details for these processes, I recommend you do some searches.

Take care & be safe!

Phil


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## ffbsm85 (Feb 2, 2012)

philddreamer said:


> I also prefer to avoid the Ag/Cl & the extra steps involved & supplies needed to acomplish what cementing with copper does in a fraction of the time.
> 
> Incinerate your silver scrap.
> Digest silver in 50/50 distilled water/ nitric
> ...



I have done a lot of reading and research and I've found a lot of the basic steps, I'm more focusing on the fine details and exactly what happens at each step. Now when you say the life of the silver nitrate, thats something I've been curious about. I've found powdered silver nitrate. How does that compare to lets say 999 silver disolved in nitric acid. Would you be able to make a silver nitrate solution to cement silver with powdered silver nitrate? Or would that have to be put in nitric acid?


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## ffbsm85 (Feb 2, 2012)

Also, whats the process of incinerating silver and why is that done?


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## ffbsm85 (Feb 2, 2012)

Geo said:


> actually thats more complicated than it should be. dissolve the silver in dilute nitric (70% nitric acid) 50/50 water to acid. cement with clean copper until no more copper goes into solution. rinse cemented silver in water until water stays clear. filter and dry. cast into anode bars for silver cell to make pure silver or sell cemented silver bars as is at about 98% pure.



So "dilute nitric (70% nitric acid) 50/50 water to acid" would mean 35% nitric acid, right? And will the acid evaporate out? If so does cementing need to hapen quickly?


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## element47 (Feb 2, 2012)

There is one thing that I notice when (because it has happened multiple times in the mere year or so I have been here) well-intentioned (and NOT well-intentioned) folks try to post their own "summaries" or "cheat sheets" on a refining process. While we all encourage the asking of specific questions, I believe the concept of regenerating an overall-process-cheat-sheet should be discouraged. 

And the reason I say that is that newbs (a word I use without any intended negative implications, just as a word for "beginner") may define for themselves certain terms improperly. Example: "cement" or "cemented" silver. The reality is actually quite simple, but we have all seen many, many questions about what the heck "cemented" silver is. Whenever someone asks what "cemented" silver is (or any one of two dozen other terms) I believe it raises doubts as to exactly how much research the person asking has done. 

Most of "our" processes are concisely explained in Hoke and demonstrated Steves' videos. The effort to rephrase this or that step or to anticipate whether a newb's summary implies that they do or do not have safety gear or do or do not regard respect fume control or do or do not put their vessels in catch vessels in case something breaks is greater than the effort that the truly sincere newb should be putting in to read the process from existing sources. There is danger in re-interpretation. 

I find this short video shows MOST OF the steps quite well. http://www.youtube.com/watch?v=kq1W-QdMsWQ 

The video cannot show you what tenmperature the process works well at, why you have to shake off the Ag crystals periodically so as to avoid shorting out the power supply, how many times the electrolyte can be used, why you want to start with the purest anode material you can

I repeat, I am not a forum moderator, not even close, and I do not wish in any way to discourage individual questions developed after repeated study of the basic source information. But re-creating the entire process, step-by-step, multiple times, so that someone can have the process on a 3x5 card taped to the wall is not only why we have cut and paste and links, it is dangerous because one never knows what is in another's mind when a piece of jargon is used.


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## Geo (Feb 2, 2012)

you incinerate to remove organics as much as possible, dirt, oil, crud, varnish and body parts (hair, skin, blood, sweat).

yes dilute nitric acid(35%) will work fine. set on low heat and cover container with a watch glass (also you may dilute using H2O2 as a substitute for water, this helps retain the nitric in solution).

when the reaction stops filter the solution and add any undissolved solids into your next batch.


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## ffbsm85 (Feb 2, 2012)

element47 said:


> There is one thing that I notice when (because it has happened multiple times in the mere year or so I have been here) well-intentioned (and NOT well-intentioned) folks try to post their own "summaries" or "cheat sheets" on a refining process. While we all encourage the asking of specific questions, I believe the concept of regenerating an overall-process-cheat-sheet should be discouraged.
> 
> And the reason I say that is that newbs (a word I use without any intended negative implications, just as a word for "beginner") may define for themselves certain terms improperly. Example: "cement" or "cemented" silver. The reality is actually quite simple, but we have all seen many, many questions about what the heck "cemented" silver is. Whenever someone asks what "cemented" silver is (or any one of two dozen other terms) I believe it raises doubts as to exactly how much research the person asking has done.
> 
> ...



I get everything that you said, but starting from basically no knowledge and searching this site is actually very difficult. You find a lot of people talking about things that they know about, but no explaination of whats happening. I've learned a lot, but it's all bits and pieces and I just want to make sure I understand the whole process and everthing thats happening instead of just winging it and hoping for the best.


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## Geo (Feb 2, 2012)

Element47 brings up some very good points.

do you understand the dangers of working with nitric acid?

do you have a method of fume control?

do you understand the dangers of working with hot acids?

do you have all the necessary safety equipment? (respirators will not filter out nitric fumes)

do you understand that you cant do any of these processes in your living space?

do you understand how to deal with a spill or mishap?

do you understand how to deal with chemical waste?

answer all these questions with a yes before you attempt any of this.


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## publius (Feb 2, 2012)

ffbsm85 said:


> So "dilute nitric (70% nitric acid) 50/50 water to acid" would mean 35% nitric acid, right? And will the acid evaporate out? If so does cementing need to happen quickly?


I think that the % is by molecular weight so 35 % would not be correct (someone will correct me if I am wrong and I will learn something ).

I like going the AgCl route because I feel I get a better (read: purer) product from my feed stock which is mostly silver solder and old film. I use to sell my dore bars to a refiner rather than electrorefining them. So, the finer the dore the more money I received.


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## Geo (Feb 2, 2012)

publius said:


> ffbsm85 said:
> 
> 
> > So "dilute nitric (70% nitric acid) 50/50 water to acid" would mean 35% nitric acid, right? And will the acid evaporate out? If so does cementing need to happen quickly?
> ...



you are correct about the %. it is a difference that some standardising may have to be done with. when i speak of %, i am normally speaking of volume, if im refering to weight i will say "by weight". i know on the market acid is traded in weight and many on the forum needs to have precise measurements to calculate yields. so, when i say dilute 70% nitric acid 50/50 to produce 35% nitric acid it is incorrect but for the purposes its being used here theres no need for any more calculation than that.


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## element47 (Feb 2, 2012)

> I get everything that you said, but starting from basically no knowledge and searching this site is actually very difficult.



However difficult it may or may not be (and I happen to disagree with that statement, but that's neither here nor there and I'm not trying to start a fight) searching the forum is about 51,319 times easier than being taken to an emergency room with life threatening lung edema from inhaling a good slug of NO2 that while you were careful to produce outdoors, that blast of wind that blew the plume into your face was something you just didn't figure on. It's vastly easier than dealing with a six-figure fine from the EPA should NO2 fumes take the paint off your neighbor's Toyota Camry and kills their Camellias, they report you to the EPA, a dowdy middle-aged woman with a clipboard and a "Save the Whales!" lapel button comes out to your place, finds copper (hey, it's just copper, what's the big deal?) residues in your flowerbed and proceeds to destroy your economic life via EPA pollution citation. Or you lose your eyesight from a splash of nitric acid. 

All this so you can produce 3 ounces of silver in an unassayed blob that if you wanted so bloody badly you could just go buy for $100 or so and have it shipped so that somebody brings it to your doorstep and it's in your hand, in perfectly assayed form, shiny, in under a week, and you still have eyes that can see it and all of your assets including your home that you didn't have to sell to pay the EPA fine.


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## Harold_V (Feb 3, 2012)

ffbsm85 said:


> I get everything that you said, but starting from basically no knowledge and searching this site is actually very difficult. You find a lot of people talking about things that they know about, but no explaination of whats happening. I've learned a lot, but it's all bits and pieces and I just want to make sure I understand the whole process and everthing thats happening instead of just winging it and hoping for the best.


And now you understand why I started the "Read Hoke" campaign years ago. I'm sure you understand that none of us can afford the luxury of holding the hand of each new reader, trying to teach basic theory when it is all at their disposal by reading her book. If all readers read her book until they understood what it teaches, we'd all be on a common page. Precious few of us are educated chemists, so it's important that we use a common language so none are confused or lost. By understanding Hoke, that very thing is provided. 

It is a mistake for ANYONE that is not well versed in refining to undertake the project. There's way too many little things that must be known in order to achieve success. As a result, many get lost in the first or second operation. That wouldn't be the case if they understood the principles involved. 

Did I mention you should read Hoke's book? 

Harold


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## glondor (Feb 4, 2012)

FFBSM85. I don't mean to split hairs here, as all the advise given is good and solid.

A point tho. 70% nitric cut 50/50 is not 35% nitric acid. When we cut the nitric 50/50 we normally do so by volume IE 500ml water 500 ml 70 % nitric.

Due to the density differences between water and nitric we end up with more than 35% nitric solution. 70% nitric is .42 grams per ml heavier than water.

If the 50/50 cut was done by WEIGHT then I believe you would have the 35% nitric expected. I hope the math master GoldSilver Pro can weigh in on this. 

Not a particularly important point however it does illustrate how working with liquids of varying density's can effect the outcome of a project. Corrections requested if in error.


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## kurt (Feb 4, 2012)

glondor said:


> FFBSM85. I don't mean to split hairs here, as all the advise given is good and solid.
> 
> A point tho. 70% nitric cut 50/50 is not 35% nitric acid. When we cut the nitric 50/50 we normally do so by volume IE 500ml water 500 ml 70 % nitric.
> 
> ...



You are right glondor - I believe it was butcher (or someone) that posted a link awhile back to a conversion calculator to get dilution of acids right - can't remember where at the moment - should have book marked that one.

Kurt


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## kurt (Feb 4, 2012)

ffbsm85 - As others have already suggested - read Hokes book on refining - it will answer all the questions you are asking (& more) in detail - It is a free down load you can get right here on the forum.

Kurt


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## butcher (Feb 4, 2012)

The percentage % nitric acid is not too important with what you’re doing here (within reason). 
I agree understanding the basics and reasoning behind what you’re doing is very important, (knowing why and when) and here is where studying Hoke's and doing the experiments helps you get that understanding, (other studying will also give you that understanding).

I also think it is normally not a good Idea to make a step by step plan, like do 1,2,3,then 4, as what if something comes up a little different, what are you going to do now, something threw a monkey wrench into that nice neat little plan, by studying Hoke's Book, and getting an understanding of how solutions and metals react, and how to deal with different solutions or problems that come up, we just can figure out what the next step needed is to deal with this monkey wrench. (although having a working plan to begin with is a good step, because when we set down and figure out what we plan to do and how, we can remember things to do, we may forget if we just jumped in and stated working without thinking it through, and making a guide to go by.


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## FrugalRefiner (Feb 6, 2012)

ffbsm85,

Welcome to the forum. I'm new here as well, but since I joined I've had the "luxury" of being able to spend most of my waking hours reading because I hurt my back a month ago and I'm limited in what I can do right now (all luxuries come at a cost).

I have to agree with everyone in this group who says read Hoke. While it takes a lot of time and dedication, it's well worth the effort! Ms. Hokes is an excellent teacher who uses a building block approach to take you from the "basically no knowledge" level to a solid foundation and understanding of "the fine details and exactly what happens at each step". Read it all, even the chapters that look like they have nothing to do with what you're interested in. You'll be amazed what you learn!

No one is trying to make things difficult, but safety comes first here. No one here wants to see anyone get hurt by giving you an outline for a process without being confident you understand all the details involved. I'm not trying to be insulting in any way here, but several of the questions you've asked indicate you need to do some more reading before you attempt to put together your plan for processing your silver.

While I have some background in chemistry from high school and some college classes, and I knew enough very early on to get started, I'm glad I wasn't able to. All I could do was keep reading while my back heals. I have learned so much each and every day!

Do yourself a HUGE favor. Read Hoke. Several members have links to her book in their signature lines. Here's how to find Palladium's links: At the top right of the page click on Members. On the line just above the member information, click on POSTS. Let the screen redraw then click on POSTS again. About half way down the list you'll see Palladium's name. Click on the number of posts in the POSTS column. You'll get a list of all of his posts. Select any of them and you'll see his signature line at the end of his post. You'll find links to Hoke's book as well as both volumes of the Forum Handbook (you've also just learned a valuable search technique that another member suggested - searching a members posts). I agree it can be difficult to find what you're looking for with the search tool until you get used to it. That's why I provided the step by step to Palladium's posts.

Read Hoke and the 2 forum handbooks. Then go to Lazersteve's great site and watch his videos. Then come back and read more.

I know this is all a lot of work, but the chemicals and processes used in refining are really dangerous! Anyone who wants to do this needs to understand that and work to minimize the risks.

Dave


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## butcher (Feb 7, 2012)

Dave, that was a very well written post, Hope that back strengthens back again, so you can get out and experiment with what you are learning.


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