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从氰化浸出液中电积回收金和银的方法在工业上已采用多年了。钢毛阴极上的贵金属在达到一定的负载量以后就进行熔炼,以生产多尔合金。如果浸出液中金的浓度比较低,可先用活性炭吸附的方法使金和银富集,接着再进行解吸,以获得适于电积回收的较高浓度的含金富液。电解槽在大约80℃的温度下进行操作(系指解吸液的温度)。美国矿务局正在研究一种新型的电解槽,其特点是改善了传质过程(Improved mass transfer characteristics,以下简称IMT型电解槽)。它能从稀溶液中直接将金和银沉积在钢毛阴极上,这样就可省掉活性炭的吸附和解吸工序。这种直接电积方法的另一个优点是可以在常温下操作,不需要对大量的溶液进行加热。通过用NaOH调整稀浸出液和使电解液在阳极室内迅速循环的方法,用这种新型电解槽在常温下操作时,可以比传统的扎德拉型电解槽达到更高的电流效率和沉积速度。
The method of recovering gold and silver from cyanide leach solutions has been used industrially for many years. Precious metals on the steel wool cathodes are smelted after reaching a certain loading to produce Dole alloys. If the concentration of gold in the leachate is relatively low, gold and silver can be first enriched by activated carbon adsorption followed by desorption to obtain a higher concentration of gold-rich liquid suitable for the recovery of the electrowinning product. The cell is operated at a temperature of about 80 ° C (refers to the temperature of the desorption solution). The U.S. Bureau of Mines is investigating a new type of cell that features improved mass transfer characteristics (IMT). It deposits gold and silver directly on the steel wool cathode from dilute solutions, thus eliminating the need for adsorption and desorption of activated carbon. Another advantage of this direct electrowinning method is that it can be operated at ambient temperature without the need to heat large volumes of solution. By adjusting dilute leachate with NaOH and rapidly circulating the electrolyte in the anode compartment, higher current efficiency and deposition rates can be achieved with this new type of cell than at conventional Zadla cells when operating at ambient temperature.