Not suggesting that wire won't work-and if you're assured it will be fully consumed it's not a bad idea. As it degrades it will become more and more difficult to remove from the solution, whereas a piece (buss bar, for example) would be much easier, and easier to clean as well. One comment I would make-try to not use wire. Assuming you don't plan to run the recovered material that way, the use of copper is highly recommended. I intentionally recovered traces of copper, which were used, along with other metals that got included, to act as a collector when the material was processed by furnace. I did pretty much the same thing, although in my case I did the recovery in the stock pot, using scrap steel. Frankly, that's the wise way to recover small quantities of the platinum metals, due in part to their resistance to being precipitated from dilute solutions. To my knowledge, you won't have any problems recovering trace elements using copper, regardless of your use of SMB, or not. And it might help others who are entirely new to it, that are reading. You may already know some of this stuff, but I would rather detail it out than leave someone guessing. Then if you have specific questions about the processes, just post them, and someone will help you. There are several threads on the forum for both of the topics you would be searching for, and they are discussed pretty thoroughly. Then save the combined metalic PGM powder until you can separate it with refining, as already mentioned above. These precipitations can be very fine black powders, especially toward the end. Check it each day, and when it looks like no more has come down, test the solution with stannous chloride to be sure. Note: It can take about a week for all the PGMs do cement out. This also lets you see if the copper is accumulating values, and if it is, you can knock it against the jar to remove it, usually. The spiral should be suspended horizontally above the bottom, so the values will mostly fall off, onto the bottom of the container rather than bunching around the copper and possibly lessening the surface area. You can bend it into a flat spiral to get more surface area into the solution (leave spaces between the wires for the cemented metals to fall down through), then bend a hook on the other end to hang it on the lip of the jar or beaker. Copper busbar is recommended, but heavy copper wire will work, like size AWG # 0-0 bare ground wire. Avoid copper tubing because it's difficult to scrape cememted values which may stick to the inside of it. Powdered copper will contaminate the precipitated PGMs. If your solution has lots of color, making the stannous test uncertain, just cement the PGMs out with solid copper. If PGMs are in the solution after precipitating all of your gold, just save the solution until you have the knowledge and chemicals to separately drop them. This will tell you if all the gold has precipitated yet, and also if there are PGMs remaining in the solution.
#GOLD PRECIPITATE HOW TO#
What I would recommend, as an immediate solution to the problem, would be to drop your gold, then test the remaining solution with stannous chloride testing solution (this procedure and resulting color indications, as well as how to make this testing solution, can also be found using the search function). You can find the specific processes for precipitating PGMs by using the search function near the top of the page. I would appreaciate every comment on these questions. I wonder, if Cu process has better efficiency than SMB one, especially for PGMs? What is your opinion on such process? Copper price is low in comparison to noble metals. In precipitate Au and Pt would be present, the mixture quite easily separable. The last process would allow to dissolve remaining Cu together with Pd. This should be followed with careful rinse with distilled water (a few times to remove Cl-), and then with HNO3.
I would use copper powder, as it has great surface per mass unit. Am I right? What could be the efficiency?Īnother possibility to precipitate gold together with PGMs is to use metallic copper. In my opinion Pd precipitates slowly as a very fine black powder (which might escape through filters?). My question concerns precipitation of PGMs from acidic solutions (HNO3 not present)ĭo palladium and platinum precipitate with sodium metabisulphite? I have an impression, that this process occurs, but in noticeable longer time than for gold precipitation. For a few weeks I enjoy refining of gold from different electronic waste.
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