METHOD TO EXTRACT METALS FROM MILL TAILINGS Russian patent published in 2012 - IPC C22B7/00 C22B3/04 

FIELD: metallurgy.

SUBSTANCE: method includes joint leaching and activation of raw materials in a cage mill with extraction of metals into a solution simultaneously with crystal damage. Prior to supply of raw materials into the cage mill, it in the mixture with elemental sulphur is previously treated with a solution of a mixture of sulphuric and nitric acids. Raw materials are mill tailings in the form of a pulp at the weight ratio of a solid phase to a liquid phase equal to 1:2. At the same time they are ground in the mixture with elemental sulphur in the amount of 12% relative to the mass of tailings to the size of 100% - 0.01 mm. Pulp treatment with a mixture of sulphuric and nitric acids is carried out at the weight ratio of the latter equal to 2:1 to bring the hydrogen index pH to the value of 1 with its further increase to the value 3 for 2 hours.

EFFECT: higher efficiency of metals extraction from mill tailings due to increased chemical activity of the latter.

2 cl, 1 ex