Leaching of Impurities from Poor Intermediate Products of Refining Production in Autoclave Conditions.

At elevated temperatures (130 and 180°C) in hydrothermal autoclave conditions, the possibility of deep extraction of noble metals from poor intermediate products of refining (or affinage) production was investigated. The conditions (temperature, processing conditions) of leaching of impurity elements into the solution are determined, under which the uncontrolled distribution of precious metals according to the technological scheme is prevented and their concentration in the solid phase is ensured. It was found that the processing of the poor intermediate product in two stages (alkaline and acidic) under autoclave conditions makes it possible to increase the total content of noble metals in the solid phase from 0.5 to 17.5 wt %, which allows returning this product to the refining cycle. In this case, more than 99 wt % tellurium passes into a solution that does not contain impurities of noble metals and is suitable for further processing. [ABSTRACT FROM AUTHOR]