Prospects for by-production of rare earths during uranium recovery from in-situ leaching solutions

Abstract

Russia possesses huge and variable resources and reserves of rare and rare earth metals. At the same time, the existing methods of recovery of rare earth elements (REE) from the conventional sources are rather complicated, while the commercial production is impeded due to the lack of the appropriate infrastructure in the area of concentration of REE. By-production of rare earth metals at operating in-situ leaching mines with the mature infrastructure is also a promising way of REE recovery enhancement. Out of geochemical associates of hydrogenous uranium (selenium, rhenium, vanadium, molybdenum), only rhenium was extracted from process solutions. This article considers the by-production prospects of yttrium and lanthanides from pregnant solutions of in-situ leaching (ISL) during uranium production at the deposits in Khiagda ore field. Based on the lab-scale and full-scale studies, as well as the tests using a mobile research plant, the basic diagram is developed for the rare earth recovery from the in-situ uranium leaching solutions. In the long view, it is required to undertake semi-commercial trials of the proposed flowsheet for the recovery of rare earth elements from ISL solutions with production of bulk REE concentrate. The main areas of the further studies into the by-production of valuable components together with uranium from ISL solutions should be finding of new selective ion-exchangers for the preliminary concentration of valuable components (middlings), as well as effective extraction and precipitation technologies for deactivation and purification of middlings and final products. REE 227Ac recovery from concentrate improves the economic efficiency of by-production.