METHOD FOR THE SORPTIVE EXTRACTION OF PRECIOUS METALS

摘要

The invention relates to hydrometallurgy and can be used for extracting precious metals (palladium, platinum, gold and silver) from different types of raw mineral materials. The method for the sorptive extraction of precious metals from mineral raw materials containing alkaline and alkaline earth metal chlorides involves the sorption of the precious metals from a pulp using a synthetic sorbent that contains strong base and weak base functional groups, followed by desorption. The sorbent is washed in two steps; in the first step, the sorbent is washed with the liquid phase of the waste pulp and water, and in the second step, the precious metals are desorbed using a hydrochloric acid solution of thiourea. The precious metals are then precipitated from the thiourea solution into a collective concentrate using an ammonium hydroxide solution; furthermore, said process is carried out in a cascade of six devices with screen drainages with a fixed volume of sorbent load in each device, the precious metals are desorbed at a temperature of 50-60°C using a solution that contains 60-80 g/dm3 of thiourea and 3-10 g/dm3 of hydrochloric acid, and the precious metals are precipitated using an ammonium hydroxide solution with a pH of 8.7-8.8 and a temperature of 50-60°C.