Rational Parameters for Uranium Concentration in Pregnant Leach Solution under In Situ Leaching Conditions

Abstract

The aim of this study is to develop and validate rational parameters for uranium concentration from pregnant leach solutions (PLS) with low uranium content during late-stage operation of technological blocks remote from the processing plant, with the objectives of improving processing efficiency, increasing labor productivity, and reducing operational costs. The study is motivated by the growing number of late-stage blocks at Kazakhstan uranium deposits characterized by low productivity and declining PLS uranium content. Pumping large volumes of low-grade PLS reduces processing efficiency and increases specific energy and labor consumption, thereby raising operational costs and the unit cost of the final product. Development of rational concentration parameters will increase the mean uranium content in the header pipeline, reduce specific costs at the sorption-desorption stage, and improve overall processing plant throughput. Application of the mobile concentration unit reduces the annual PLS volume directed from a single block to the processing plant to approximately 5,000 m³, representing a 5-6% reduction in total solution volume, with uranium concentration factors of 309 times. To determine process parameters, a series of laboratory sorption-desorption experiments were conducted using the selected sorbent. Based on the results obtained, a pilot concentration unit was designed, fabricated, and deployed on the geotechnological field, and pilot-scale tests were carried out at an operating mine site.