METHOD OF EXTRACTING RARE EARTH AND NOBLE METALS FROM ASH AND SLAG Russian patent published in 2015 - IPC C22B11/00 C22B59/00 C22B7/00 C22B3/18 

FIELD: chemistry.

SUBSTANCE: method includes preparation of ash and slag, mixing them with leaching solution, accumulation of biomass of microorganisms, bacterial leaching of rare earth and noble metals, separation of obtained suspension into sediment and clarified liquid with isolation of rare earth and noble metals from the latter. At the stage of accumulation of biomass of microorganisms saturated solution of calcium carbonate is added in amount 1-10% of leaching solution consumption. Bacterial leaching is performed in mode of multi-chamber floatation with aeration intensity 0.1-0.5 m³/m²·min. Intensity of aeration in each following chamber is reduced by 5-10% in comparison with the previous one. Bacteria of genus Acidithiobacillales are used as microorganisms. Floatation is performed with application of finely disperse aeration with average size of bubbles 20-30 mcm. Size of bubbles in any following chamber is increased by 10-15%.

EFFECT: increased extraction of rare earth and noble metals from ash and slag due to intensification of organism cultivation process.

4 cl, 3 ex