Noble Metal Recovering by Electroless Displacement Deposition on Silicon Powder

摘要

We developed a low-cost, efficient method to recover all noble metals including gold, silver, palladium, rhodium, platinum, osmium, ruthenium, and iridium from aqueous solutions by simply adding hydrofluoric acid (HF) and silicon (Si) powder. The recovery rate depends on the specific surface area of Si, the HF concentration, and the solution temperature. Our method selectively recovers noble metals and copper from a mixture solution of noble and base metal ions, such as nickel, cobalt, and iron, and obtains pure noble metal powder by dissolving Si. The Si powder and the HF solution are expected to be supplied from semiconductor industries, such as the sawdust Si of wafering or dicing and the waste HF solution of wafer cleaning or etching. This new method recovers noble metals from waste (urban mines) using other waste; it also has green electroless deposition.