PYRITE CINDER PROCESSING METHOD Russian patent published in 2021 - IPC C22B11/00 C22B7/00 C22B3/08 C01G49/06 

FIELD: hydrometallurgy.

SUBSTANCE: invention relates to hydrometallurgy of black, non-ferrous and noble metals from pyrite cinder. Pyrite refuses are processed for further extraction of iron oxide (Fe₂O₃), gold and silver. Method involves grinding of ash in a cascade of wet grinding mills to produce a water-containing pulp with particle size of 5 mcm or less. Pulp is pre-treated with sulfuric acid solution with concentration of 100 g/l with dispersion of pulp with oxygen for 6 hours at temperature 80 °C at ratio of solid and liquid components in pulp L:S = 5:1. Method comprises filtering to obtain filter cake, which is leached with sulfuric solution of thiourea with concentration of sulfuric acid in solution of 100 g/l and thiocarbamide of 40 g/l, at temperature of 60 °C for 6 hours and ratio of L:S = 4:1 in a reactor with mixing by means of twin hydrodynamic impellers to obtain enriched cake containing Fe₂O₃ and a productive solution containing gold and silver. Enriched cake is washed from productive solution, dehydrated, dried and calcined at temperature of up to 900 °C for obtaining iron oxide, and said productive solution is subjected to electrolysis for extraction of gold and silver.

EFFECT: method enables to carry out environmentally safe, fast and efficient processing of pyrite cinder with increase of subsequent extraction of valuable components in form of iron oxide, gold and silver.

1 cl, 3 tbl