wildjoker said:
So I should go through inquartation in your opinion. But beeing more specific, should I add more base metal as says the normal inquartation process or simply process this mix of metals I´ve already laminated?
What I would do in the same situation is sort the materials, so you know what you have. Avoid combining junk jewelry, which can contain elements that can create problems in refining, and lend little, if anything, to the recovered values. Any known pieces of platinum would not be melted, but removed. The average karat would be calculated, then silver scrap would be added to lower the overall gold content to roughly 25%. Once melted, the alloy is then poured in water to generate what I call corn flakes. These small bits present a large surface area to nitric and water, allowing for all of the base metals (including silver) to be removed before dissolving the values.
When processing with nitric, does the gold stay in metallic form?( just to confirm my readings as most say it stays)
Yes. Because gold will not dissolve in any single acid, it is not dissolved, but left behind in a honeycombed configuration, which is very desirable. If the inquartation (the word springs from the concept of quartering, or 25%) is much below 25%, the gold starts to disintegrate, often going into suspension. Once that happens, you must wait until the suspended particles settle before decanting the solution. No harm, but it slows down the operation. If, on the other hand, the inquartation isn't low enough, the amount of gold present has the potential to protect the base metals from nitric, so you get incomplete dissolution. When the exposed gold gets dissolved by AR, the remaining portion, which still has a preponderance of silver, will form a hard green/gray crust of silver chloride, which isolates the alloy from AR, stopping the process.
Harold_V said:
By processing the metals with nitric, before introducing AR, you would remove the bulk of the base metals, along with silver and palladium, plus traces of any platinum that may be present. They values would then be recovered with copper, including the Pt. group metals, assuming you leave them in contact with copper long enough. They are last to cement from solution, which becomes obvious by keeping watch on the color of the solution, and the color of the cemented values. As the Pt. group precipitate, the color of the solution generally shifts from green to blue, and the cement gathers a black deposit.
What kind of copper? can I use a bar of copper for example?
Large pieces are desirable, so you can retrieve them after cementation. If you use wire, if it isn't totally consumed in the process, it can be difficult to retrieve. That somewhat defeats the purpose in recovery, leaving behind unwanted copper. That limits the useful life of your electrolyte in a parting cell.
what happens, the copper takes place in the reaction with the acid and the other metals precipitates?
Exactly. The copper is consumed in the process, so it is sacrificial. Works the same way zinc does, but is highly selective in that it won't precipitate anything but values.
Harold_V said:
The Pt. group values would be recovered from the silver when the silver was parted in an electrolytic cell, and would report in the slimes. That's pretty much the conventional method of purifying silver and recovering trace values. It works extremely well and is an interesting process to perform.
I have no clue on how to work with an electrolytic cell, can you point some literature on this subject,please?
A silver cell isn't complex-----one can be constructed from something as simple as a stainless container from a restaurant steam table. For the moment, it's more than I'd like to spend time on, but you might enjoy a book written by Butts & Coxe (really, no joke!) , which covers silver cells quite well. I'm at a loss to provide the title, but a search by the author's names will narrow it down immediately. Should you get serious, I'd be willing to dedicate more time to its construction, and provide guidelines that worked for me.
Harold_V said:
That's true for the most part. Research has proven that a small percentage of silver will behave much like gold, and remain in a chloride solution, yet to be converted to a chloride. GSP proposes that it will self precipitate simply by diluting with several volumes of water, which parallels my experience. The balance of silver will have converted directly to silver chloride. In essence, it's safe to conclude that silver and gold can not be in solution at the same time in acid. It is that very quality that makes refining of gold so easy.
the water you add here is distilled or can be tap water? this water I add to the AR solution before I siphon the liquid(yet containing gold) and filter the silver salt or after the separation?
Many insist that it is mandatory that distilled water be used. I say that's nonsense. Unless your objective is ultra pure gold (better than 9999), the contaminants in culinary water are not a factor. I used distilled water only for making standard solutions, and for the electrolyte in my silver cell. I distilled my own, so availability was not a factor. I simply couldn't see a benefit in using distilled water, and if you've seen the picture of my gold shot, which I have posted many times, you'd see, clearly, that my quality was superb. My gold could be melted without flux and remain shiny.
If I do the process of inquartation as you proposed, this will not be an efficient way to recovery the silver from the nitric acid solution, how should I handle this?
I think that you'll find that working with silver chloride is a PITA once you've tried recovering silver on copper. I avoided silver chloride like the plague, creating it only from exceedingly dirty solutions, where drag-down of contaminants was severe. YMMV, however. It's often the case where one person doesn't mind a given operation, while others do. However, I think you'll find that most refiners will suggest you avoid silver chloride. If nothing else, it's far more demanding of your time, with little benefit.
Harold
really apreciate them!
