First, recovery gold from artifacts of gold copper
Institute for the use of recycled materials takes oxidation roasting gold to recovery of gold artifacts from scrap copper. Waste Add gold artifacts puts into roaster made of copper, the isothermal oxidation at 1000C roast for 30 minutes, remove the Add water, cover with gold foil attached to copper oxide layer with the copper-scales from the body. And then dissolve with sulfuric acid, dissolve slag separation and purification of gold. Baking characteristics of this method is that when the non-polluting emissions. Use this method to deal with 300 kilograms of copper waste artifacts can recover 1.5 kilograms of gold. Gold recovery> 98% recovery of copper matrix> 95%, and a by-product, copper sulfate can be used as pesticides.
Second, recovery of gold from the abolition of electronic components
Beijing Metallurgical Plant thinning uses precious metals I2-Nal-H2O system. Denuding waste components of the gold plating, use iron to cement or sodium sulphite to reduction to recover of gold. Regenerate iodine by sulphuric acid acidificating and potassium chlorate oxidizing. Recycling materials pension Research Institute developed a new electrolytic process. Adopt thiourea and sodium sulfite as the electrolyte, graphite as the cathode plate, gold-plated anode electrolytic waste as anode. Through electrolysis, the gold in coating is oxidated anodic for Au + immediately after the formation of networks with thiourea cations Au [cs (NH2)] 2 +, sodium reduction was for the gold, Shenyang in the bottom, the separation and purification of gold-bearing sediments was pure gold powder. Matrix material recoverable nickel and cobalt. This process for gold recovery rate is 97~98%. Product purity is> 99.95%
Third, recovery and palladium from spent catalysts
Kunming Institute of Precious Metals many oxidants increase the use of hydrochloric acid leaching, so that access to the solution and palladium, zinc replacement, hydrochloric acid plus dissolved oxidants, a net reduction of oxalic acid powder; to restore the mother liquor using conventional purification palladium.The purity of gold, palladium can be up to 99.9%. Recoveries were 97% and 96%. This has applied for patents in China.