The Problems of Rare Earth Metals Extraction from Coal Ash in the Form of Solvents and its Concentrating

Abstract

There were considered the issues of rare earth metals’ extraction from coal ash in form of solvents with its subsequent preliminary concentrating by means of biofiltration. Wherein as the collecting agent was used surplus activated sludge, which is generated at biological treatment plants. There was showed that activated sludge age virtually has no effect on rare earth metals sorption, which was used as scandium, lanthanum and yttrium. However amount of activated sludge has a significant impact on the efficiency of rare earth metals sorption, wherein the greatest effect is revealed at extraction of scandium and relatively weak influence is marked in case of lanthanum and yttrium. There was described package technology of rare earth metals’ leaching, in particular scandium, lanthanum and yttrium from waste piles of Moscow lignite basin and bottom ash wastes of utility companies in Russian Federation, which includes following stages: preparation of bottom ash wastes, chemical leaching, bacterial added leaching, bioflotation, ion exchange and subsequent sludge thickening. There was discussed in detail the issue of bioflotation stage.