METHOD FOR PRODUCING A NOBLE METAL CONCENTRATE Russian patent published in 2022 - IPC C22B11/00 C22B3/44 C22B7/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to hydrometallurgy of non-ferrous and noble metals and can be used for recycling waste solutions formed in the process of refining. Extraction of noble metals from spent refining solutions containing heavy metal salts includes reagent deposition of metals and separation of the resulting deposits. Deposition is executed in two stages. At the first stage, said solution is treated while stirring with calcium hydroxide to a pH of 5 to 8, followed by sustaining the resulting pulp while stirring. The second stage is executed by introducing a sodium sulphide solution into the pulp, followed by stirring the pulp. The deposition of the contained noble metals and sustaining are executed at room temperature, followed by filtering, drying, and calcining the resulting deposits at a temperature of 550 to 600°C for 2 hours, resulting in a noble metal concentrate.

EFFECT: method allows for an increase in the extraction of noble metals from spent solutions of refining production using available inexpensive reagents: calcium hydroxide and sodium sulphide.

1 cl, 2 ex