Recovery of rare earth elements from phosphogypsum

Phosphogypsum is a common large-tonnage waste of phosphoric fertilizers industry. The article describes a technology for complex treatment of a phosphogypsum Sredneuralsky Copper Smelting Plant (Sverdlovsk region, Russia) containing 0.43-0.52% of rare earth elements (REE). Joint co-crystallization of REE with gypsum provided a low degree of REE leaching in the direct leaching process. It was shown that combination of mechanical grinding treatment, ultrasonic impact and resin-in-pulp process provided significantly higher degrees of REE leaching from the phosphogypsum (from 15 to 17% to more than 70%). In addition, it was shown that the products after phosphogypsum treatment can be successfully used instead of natural gypsum as an addition for cements in the production of building materials. (C) 2018 Elsevier Ltd. All rights reserved.