美国矿业局,从1950年至1975年,经过二十五年的不断努力,改进了金银矿堆淋法,使美国西部金银矿小矿山的发展又掀起了一个新的高潮。其方法是用塑料垫代替水泥、柏油或粘土,用氰化钠加石灰与清水淋滤金银,用硫化钠从溶液中沉淀银,用粒状活性炭或粗粒焦炭代替锌粉吸收金,用近沸点的苛性钠稀溶液加酒精,加或不加氰化钠使活性炭脱金,最后在电解池中用钢毛做阴极沉淀金制金块。美国西 US Bureau of Mines, from 1950 to 1975, after twenty-five years of continuous efforts to improve the gold and silver mine heap method, so that the western United States gold and silver mine development of small mines and set off a new upsurge. The method is to use plastic mats instead of cement, asphalt or clay, leaching silver and silver with sodium cyanide plus lime and water, precipitating silver from the solution with sodium sulfide, absorbing the gold with granular activated carbon or coarse coke instead of zinc powder, Boiling point caustic soda dilute solution plus alcohol, with or without sodium cyanide activated carbon off the gold, and finally in the electrolytic cell with steel wool cathode precipitation gold bullion. American West