Siberian Federal University

Experimental results of the influence of technological parameters of phosphogypsum cascade leaching and evaporation of the solution obtained after the leaching on the rare earth elements (REE) content in it are presented. It was found that REE concentration in the solution grows almost linearly with increasing number of cascades [1]. Evaporation of REE – containing [2] solution down to 23 % of the initial volume leads to precipitation in which REE is about 0.5–0.6 % which coincides with the content of REE in the initial gypsum. This leads to purification of the solution from non – REE. At evaporation of the solution above 77 % an increased content of REE reaching 10–12 % was found in the precipitation. Thus, cascade leaching followed by solution evaporation is a cost-effective technological process. It allows obtaining a solution containing from several tens to few hundreds grams REE per liters with low content of Ca, P, S, Sr and other undesirable elements, which can be used for precipitation of REE carbonates or hydroxides [3]