# electrolyte question



## Dawnsdad (Apr 10, 2012)

I have been dissolving pieces of braze that is about 50% silver and 30% copper using nitric acid. The first batch of depleted acid always has so much copper and no silver. I normally precipitate using a saturated brine solution. When I do get silver chloride, it eventually makes its way to the furnace. The refiner that I have been selling to tells me that the bars I have sent our 99%. I want to use electrolysis to refine to .999. I am curious as to whether I can use the copper nitrate solution as an electrolyte for the electrolysis. I suspect that I couldn't if I have treated it with brine. But I could test a small sample to be sure that there is no silver and, if not, use the rest as an electrolyte. Will that work?


----------



## FrugalRefiner (Apr 10, 2012)

Dawnsdad,

First, be careful if you're putting silver chloride directly into your furnace. The chlorine gas that will be liberated is poisonous! Better to convert it to silver oxide or elemental silver first.

Regarding using your copper nitrate as your cell electrolyte see Steve's post http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=2868. I haven't had the opportunity to try his method yet but I plan to.

Dave


----------



## Harold_V (Apr 11, 2012)

Dawnsdad said:


> I have been dissolving pieces of braze that is about 50% silver and 30% copper using nitric acid. The first batch of depleted acid always has so much copper and no silver. I normally precipitate using a saturated brine solution.


I question your logic. Why aren't you recovering with copper?



> I want to use electrolysis to refine to .999. I am curious as to whether I can use the copper nitrate solution as an electrolyte for the electrolyte. I suspect that I couldn't if I have treated it with brine. But I could test a small sample to be sure that there is no silver and, if not, use the rest as an electrolyte. Will that work?


Absolutely not! Electrolyte for a silver cell must be comprised of silver nitrate, with NO traces of chlorides present. 

If you study enough, you'll come to understand that some copper is included in the electrolyte (a small amount) for silver cells, although it is not a requirement. Its presence improves conductivity, permitting lower silver content, but, more importantly, permits easy harvesting of the silver crystals that grow. I ran my silver cell for years, never adding copper, so I'm very familiar with how a cell behaves, and, contrary to what has been posted on this forum, the lack if copper does NOT cause fine threads to grow. Quite the contrary, low or no copper content causes silver to deposit in a firm sheet that adheres quite well to the cathode. Once copper level rises (a natural phenomenon when processing silver that has been cemented with copper), crystals quickly begin to form, and the solid plating ceases. 

There is an excellent book that will provide needed guidance. I don't recall the title, but it is written by two gentlemen, Butts & Coxe (really!) Search the internet for books on silver. It's easy to find. 

Harold


----------



## NobleMetalWorks (Apr 11, 2012)

Harold,

Is the book you are thinking of called 

"Silver: Economics, Metallurgy and Use"

I was reading something about an Electrolytic stripping cell that made mention of the same authors you did, and that was the name of the book that was referred to, but the title doesn't really say anything about a stripping cell.

I found it for sale easy enough, I would be interested in reading it, if that in fact has the information about the cell.

Thanks


----------



## Harold_V (Apr 11, 2012)

That's the book. I have a copy, but it has been in storage for years, so I haven't looked at it for quite some time. 

It isn't a "how to" book, but it contains no end to useful information, assuming you have an understanding of the basics of parting silver. I relied upon it when I set up my small silver cell and found it to be more than adequate. In my opinion, it belongs in anyone's library that has an interest in silver. I believe that GSP would endorse the book much the same way I have. 

Harold


----------



## NobleMetalWorks (Apr 11, 2012)

Thanks Harold,

I found I copy and went ahead and purchased it.

If you ever pull your old books out of storage, and there is anything you want to part with and pass along, keep me in mind? :mrgreen:


----------



## Harold_V (Apr 11, 2012)

Will do, although I'm not one for selling possessions. Learned that lesson the hard way when I traded off a 458 magnum rifle that was custom built for me by P.O. Ackley. Traded it to a friend, but had better thoughts afterwards and got it back. Good thing, too, because the friend was burglarized not too long afterwards and lost all of his guns. The 458 would have been gone forever. 

The book in question should prove to be quite valuable to you, although, like I said, it isn't a book like Hoke's, which teaches you processing. Still, with some interpolation, you can gleam one hell of a lot of useful information. It was from that book that I determined how much amperage I'd run with my cell. It also discusses electrolyte to some end, and should detail the importance of copper in solution, and the upper limits that can be tolerated. Too much copper guarantees poor quality, as copper gets included in the processed silver. 

Harold


----------



## NobleMetalWorks (Apr 11, 2012)

I understand about possessions, specially books. I become very attached to my books.

All the help is greatly appreciated, there is a lot of information floating around out in cyber space, but I prefer books, however, so much of it is out of print and difficult to find that it's hard to even know where to look for the correct information. Someone like you, who knows which books are the better ones to read, and what they apply to, is invaluable. There is no way I would have known, even if I came across that book, that it contained the information I need.

Anyway, thank you for passing on the information, and everything else.


----------



## Dawnsdad (Apr 11, 2012)

Harold_V said:


> Dawnsdad said:
> 
> 
> > I have been dissolving pieces of braze that is about 50% silver and 30% copper using nitric acid. The first batch of depleted acid always has so much copper and no silver. I normally precipitate using a saturated brine solution.
> ...



I worked at a local branch of a major brokerage firm back in the 70s. One of my customers was in the business of recovering silver from x-ray processes. He had electrolysis machines hooked up in the developers for virtually every place that had an x-ray machine in all of West Texas and eastern New Mexico. That was when silver was $2-$3, before Jimmy Carter. During the big price run-up in the Carter years, it was hard for him to get the major refiners to commit to purchases from him due to the price volatility. At the same time my phone was ringing off the wall with people who wanted to buy 20 to 100 ounces of silver. We weren't set up to sell actual silver, only futures contracts. So Joe and I worked out a little side business for a while. Well, Joe has been retired now for a few years but he still lives in the area. When I came across my current opportunity to acquire scrap that has significant silver content, I went out and spent a while learning from Joe. He had always used brine to precipitate his silver. He was my primary information resource until I found this forum. But even when I learned about using copper, I tried it and it seems much slower and much more expensive than using salt. The sweeps that I have been getting have yielded about 1 ounce silver per pound. If I get the deal that I am working on, I should have about 400 pounds of this raw material per month. It seems to me that recovering that much on a regular basis would be a lot more time-consuming and expensive. But I am always open to suggestions. Maybe someone can convince me that the extra time and cost would be worthwhile. I will say this, I am not exactly thrilled to be dealing with chlorine gas. I have ordered laserSteve's Silver DVD and have seen info on converting silver chloride using sodium hydroxide and syrup. That may be better than using the furnace and soda ash. Maybe someone can post a pros versus cons comparison between using copper and salt.


----------



## Geo (Apr 11, 2012)

Dawnsdad, look at it this way. if you cement with copper, your end product from this one process (if done correctly) will be 99.5 and its just one process.if you precipitate with salt, you have added 5-6 more processes and added two more materials to your final product. cementing should be considered a convenience, and with any convenience you have to spend a little extra. in this case the little extra is the price of the copper used and the time it takes to cement (which you can lessen the time by using a larger area and adding a little heat).it all comes down to what you feel comfortable doing. personally, i never liked the idea of evaporating to remove nitric and avoided using AR because of it, but once i experimented until i was able to do it correctly, i cant imagine how i got along without it.


----------



## butcher (Apr 12, 2012)

Cementing on copper in my opinion is faster and easier than forming silver chloride.

Cementing silver with copper may not come down out of solution as fast as forming silver chloride, but the overall process is much faster.

Silver cemented using copper there is less loss of silver in the process, as if silver chloride was not completely converted to silver metal before melting, some of the silver goes up in smoke.

Cemented silver can be washed and melted directly, silver chloride needs converting to metal, which also means more volume of waste to deal with.

Make up your own mind, try a small batch of each process, see which one you spend more time and trouble on and see also which one you get back all of the silver, and which process you like better.


----------



## gold4mike (Apr 17, 2012)

Geo,

You mentioned above that you can speed the cementation process by using heat. 

If you use heat and the solution is allowed to cool will some of the copper also start to drop back out of solution?


----------



## Geo (Apr 17, 2012)

only if the solution becomes saturated with copper. the process should be completed well before that happens.as i understand it, the atoms are excited as energy is applied (energy=heat) which cause the reaction to speed up.so its best to keep an eye on the reaction and not to apply too much heat. im sure theres a formula that can be followed as to how much heat should be applied. if you have time and speed isnt a factor then heat wouldnt be needed.if your like me, you want things to happen as fast as possible and still achieve the same results.


----------



## butcher (Apr 17, 2012)

Heat can also circulate the solution, this being a contact process, the circulation or stirring will help the solution to come in direct contact with the copper so the copper can replace silver from the solution through an electron exchange process, copper nitrate is highly soluble, so as long as you do not evaporate too the solution much, the copper nitrate crystals if they do form to some degree would wash out easily, heating could also help the reaction if the acid content was low as the remaining acid would be stronger, on the other hand if you had excess nitric acid the heat would help to use this up dissolving copper into solution.


----------



## Palladium (Apr 17, 2012)

I use heat when i cement my silver. What I mean is I heat it up and then after I take it off the heat I start cementing. It seems to come down finer which seems to wash in the Buchner better for me. One thing i have found with heat is if you have excess nitric then the silver will drop and immediately go back into solution, then drop, go back into solution, until a medium is reached. This will lead to a lot of copper in your crystals and is a pain in the ** to clean up. More so than with a cold solution it seems.


----------

