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Separating Precious Metals eScrap (3 replies)

Carmen Ibanz
9 months ago
Carmen Ibanz 9 months ago

"Diamond Soaks" for Separating Precious Metals from Precious Stones: Are There Any New and Efficient Methods Better Thank Aqua Regia Then Sieve Shakers? This is a process for recycling by separating precious stones from gold, silver, the platinum group metals and the base metals alloyed into the precious metals by way of dissolving the metals and leaving the stones undamaged. The standard process used aqua regia and the problem is that the stones remain in the bottom of the reactor with the insoluble consisting of silver chloride, undissolved metals (rhodium for example) and other insoluble (usually pieces of enamel used in decorating the jewelry, etc.).

Sieve shakers will separate the stones from fine particles of insoluble, but many larger pieces of insoluble remain with the stones. We are milling this in jar mills with ceramic grinding media, but the cutlets of many stones are damaged in this process hence I seek a better way.

9 months ago
Oberstorm 9 months ago

Look at gravity concentration. The process would be jigging. The stones have a significantly lower specific gravity than the metals. The metals will concentrate and the stones will report to the tails. Sepor has a small jig and the Quinn Process Equipment has a larger jig. But the size is dependent on the amount of material to be process. I suggest you give the people at Quinn a call and discuss this option.

Tony Verdeschi
9 months ago
Tony Verdeschi 9 months ago

The complex compounds of Ag are soluble such as [AgCl2 ]-, [AgCl3 ]2- and [AgCl4]3-, at the same time, the agents such as KCN,Na2S2O3,Na2SO3 and NH3 also could form soluble complex compounds with Ag element. According to that character, I suggest you may leach your materials by those agents.

Marshal Dienes
9 months ago
Marshal Dienes 9 months ago

You can use AR with ultrasonic, this will help in agitating impurities so that you have better results separating Au from other metals. Properly alloyed metals should not dissolve and leave behind large pieces of metals such as Pt or Rh. If this is the case, you can be assured you still have Au in these pieces. You can also try a second process of AR. Also, making small additions of Nitric Acid instead of making up a typical solution of AR may allow the HCl to attack base metals, leaving more difficult metals that need a strong oxidizer on the surface so that when you add Nitric they are more exposed. This gives you deeper penetration.

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