METHOD OF INTEGRATED TREATMENT OF PYRITE CINDERS Russian patent published in 2017 - IPC C22B11/00 C22B30/04 C22B3/10 C22B7/00 

FIELD: metallurgy.

SUBSTANCE: invention can be used to produce pure iron compounds, non-ferrous and noble metal concentrates from pyrite cinders that are waste products of sulfuric acid production. Leaching of iron and non-ferrous metals is carried out in a counterflow mode in two stages using a solution of hydrochloric acid with a concentration of 150-240 g/l, at a temperature ≥of 60°C. The undissolved residue is separated from the solution, washed off excess acidity and sent to the recovery of noble metals. Hydrochloric acid solutions after leaching are treated with chlorine gas, the pH value is adjusted to pH=0.5, then metal sulphides or hydrogen sulphide are dosed in them, arsenic precipitates are recovered from the solutions. After separation of the solution from the precipitate, thermal decomposition of ferric chloride is carried out to produce pure iron oxide. The evolved hydrogen chloride is trapped by solutions of washing the precipitation after cinder leaching. The obtained hydrochloric acid is returned to the stage of hydrochloric acid leaching of new portions of the cinder.

EFFECT: increasing the recovery of iron, non-ferrous and noble metals.

5 cl, 5 tbl, 3 ex