METHOD TO EXTRACT METALS FROM SULPHIDE MINERAL RAW MATERIALS Russian patent published in 2012 - IPC C22B3/18 C22B3/08 C22B15/00 C22B23/00 C22B11/00 

FIELD: metallurgy.

SUBSTANCE: method includes leaching of ground raw materials in a solution of sulphuric acid with concentration of more than 2.0 g/l, containing ions of trivalent iron of more than 10-12 g/l, while mixing, at the temperature up to 100°C, solid phase content to 60%, at least in two serially connected reservoirs. The pulp discharged from the last reservoir is separated into solid and liquid phases. At the same time the solid phase is returned for leaching into the first reservoir. Iron oxidation in the liquid phase is carried out with iron-oxidising bacteria adsorbed on a neutral carrier at the pH 1.4-2.2 and 90°C with aeration by gas containing oxygen and carbonic acid. Then the liquid phase is returned after iron oxidation into leaching reservoirs, and metals are extracted from the produced phases. Besides, leaching is carried out with aeration by oxygen-containing gas. The pulp discharged from each reservoir is separated into solid and liquid phases. The solid phase is sent for leaching to the next reservoir, and the liquid phase is prepared prior to oxidation with bacteria. Duration of leaching is increased in each subsequent reservoir.

EFFECT: higher speed of bacterial iron oxidation and efficiency of sulphides dissolution, reduced dimensions of devices for bacterial oxidation of iron.

13 cl, 3 ex