Method for removing impurity silver in reduced gold powder

Abstract

The invention provides a method for removing impurity silver in reduced gold powder. The method comprises the following steps of primary digestion, washing, secondary digestion and drying. According to the method, the impurity silver in the reduced gold powder is removed by adding independently prepared boiling washing liquid A and boiling washing liquid B into the reduced gold powder with relatively high silver content step by step, so that the purification of the coarse gold powder is realized, the problems of gold product fluctuation or gold powder reworking and the like caused by trace silver impurities are solved, the direct recovery rate of gold is improved, the reworking cost is reduced, and the production and operation indexes in the gold smelting process are comprehensively improved; the method can be applied to precious metal purification processes and precious metal separation processes.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and relates to a method for removing impurity silver from reduced gold powder. Background technique [0002] Gold and silver in precious metal mineral resources are associated with each other, and precious metals such as gold and silver in mineral resources are often recovered from smelting tailings such as nickel, copper, and lead. Dissolution-selective reduction" and other processes, silver and gold are separated in the process of chlorination and dissolution, and the chlorination reaction of silver and chloride ions can generate silver chloride precipitates. The high concentration of [Cl] produced by the reaction is complexed with silver chloride to produce silver dichloride complex ions and (AgCl) 2-, and the silver dichloride complex ions are easily reduced during the reduction process of the chlorination solution. Because elemental silver or silver chloride is doped in the gold powder, ...

AI Technical Summary

Problems solved by technology

[0002] Gold and silver are associated with each other in precious metal mineral resources, and precious metals such as gold and silver in mineral resources are often recovered from smelting tailings such as nickel, copper, and lead. Currently, the commonly used gold smelting methods are "chlorination dissolution-extraction-reduction" or "chlorination Dissolution-selective reduction” and other processes, silver and gold are separated during the chlorination and dissolution process, and silver and chloride ions in the chlorination reaction can generate silver chloride precipitates. Since the chlorination of gold aqueous solution needs to reach an oxidation potential above 1000mv, chlorination The high concentration [Cl] produced by the reaction undergoes a complex reaction with silver chloride to produce silver dichloride complex ions and (AgCl) 2-, and the silver dichloride complex ions are easily reduced during the reduction process of the chloride solution Elemental silver or silver chloride is doped in gold powder, resulting in the silver content in gold products exceeding the quality standard requirements. The original production process mainly uses the following methods to remove impurities and purify high-silver gold powder: 1. Use hydrochloric acid, nitric acid and other reagents to boil and wash. The removal of silver is not complete, and there are problems such as a large amount of gold loss; 2. The gold powder is reworked to dissolve and restore more than one time, the production cost of gold is high, and the yield is low

The above problems lead to low utilization rate of gold resources. Therefore, it is necessary to carry out efficient purification work for the impurity element silver in high-silver-containing gold powder, so as to ensure the effective improvement of the comprehensive utilization level of gold resources.