PGM-Au-Ag.
Please take my post as I intend it (to help).
PGM-Au-Ag said:
After recovering gold foils from an AP solution, I have a dark blue precipitant from using sodium hydroxide at a ph level of 8-9. What form of copper is this and how can I get this to a copper powder? Plan to use copper as the collector in a flux for smelting the gold foils. Would using Zinc be better to get the copper powder from AP?
Why did you use a base like caustic soda on the acid peroxide? It could have been reused as acid peroxide, the copper hydroxide powder would just oxidize in a melt, to get this copper back to a metal I would add some acid low heat and a metal higher in reactivity series, my choice would be iron or zinc, (not aluminum unless you used sulfuric acid on the copper) aluminum chloride is hard to deal with as a chloride waste it forms a jell compound hard to settle and very hard to dry, iron or zinc is much easier to deal with.
Why would you want to add back a metal to the almost pure gold foils in a melt (base metal as collector) this makes no sense at all, (that is like taking one step forward and going twenty steps backazzwards), you could melt them as foils but the quality of the metals would sill be lower than if you went to the next step of refining,(but much higher purity than if you added a bunch off copper in a melt),melting the gold foils after a wash would not give pure gold but gold of very high content, study and go the next step and purify the gold in the HCl and bleach process, before melting the gold powders, the foils would need cleaning before proceeding to this step, also from your comments on recovery and refining you would need to do some homework before proceeding, to this list of things to study look at Harold’s post on washing the gold (brown) powders it is in the post getting gold pure and shining in the help needed section.
In a melt of an ore, the metal used to collect the values is used because you would not be able to separate them from the gangue materials or they would not join to form a button in the melt, that is not the case when the majority of the material is a metal, or powders of the metals.
Some metal powders may need a flux recipe chosen to reduce the metals to metal in the melt, metals that may normally oxidize in the melt and burn off in smoke or report into the slag, other times we may wish to oxidize certain metals in the melt and burn them off or make them mix into the slag.
Flux in the melt is also chosen to make certain chemical reactions to occur in the melt, choose the wrong combination of chemicals and you can oxidize all of the metals and even loose your valuable metals, or you can also reduce many of the unwanted metals into a button with the values, it is not just a dump in some metal collector and throw in some flux and melt, there is chemistry involved that needs to be understood and the ingredients chosen, many times ore is assayed to find out what flux is needed prior to the assay to collect the small amount of values involved.
Follow the procedures Patnor 1011, and others advised, but before you do, I would spend some more time studying the procedures, also re study the acid peroxide (copper II chloride leach), it seems you do not understand the process, and studying waste treatment so you understand how to deal with the toxic waste your generating.
I do not believe you have the basic understanding you need yet to experiment, until you do, it is best to follow procedures to the letter, spending time studying before doing any lab work, this way you get an understanding of how things work and why, after you truly understand these procedures then maybe you can try something new, and if it does not work, or is not what you expected you would know why it did not work, it would be much easier than always trying things you have no clue about and would never know what would work, and why things are not working like you are guessing they should..
Iron would not be a good collector in a melt Phildreamer was suggesting you convert the copper powders to copper metal with iron, (not use it in a melt), this is why he posted the reactivity series of metals, studying the reactivity series of metals can also help you understand how many of the reactions we use work and why they do.
Take your time studying (Hoke's, the forum and other materials), when you do have a process you wish to use, study it well before you begin, some processes may have several steps involved study each of these, gain a good understanding of how to proceed and what to expect when you do, this will also give you an understanding of how to correct problems as they occur.
Processing your values without this understanding under your belt is a good way to waste a lot of good material that could prove profitable.
