Title : Removal of chloride ions from copper solution, using electrodialysis techniques, to recover uranium through ion-exchange
Abstract:
This study shows the technical feasibility to recover uranium from copper Pregnant Leaching Solutions (PLS) using ion-exchange, after a removal of chloride ions using the electrodialysis (ED) technique. The original copper PLS solutions came from the National Copper Corporation (CODELCO), from their hydrometallurgical operations, which contained high concentrations of chloride ions. These solutions contained average concentrations of 22 g/L chloride ions, pH 1.5 – 1.8 and 20 mg/L uranium. The high chloride contents made the uranium recovery technically unfeasible, because of the high volumes of chemical reagents needed to operate. To eliminate the chloride ions selectively, a modified electrodialysis (ED) process was developed. The ED process was made of a three–compartment cell. This system removed selectively the chloride ions, and replaced them with sulphuric ions, without modifying the composition of the copper PLS solution, to allow a continuous operation of the copper production plant. The ED process decreased the chloride content from 22 g/L to 6 g/L. Finally, static and dynamic load tests were performed for both the original PLS and the treated PLS, using 3 different anion exchange resins: Dowex-1, Lewatit A365 and Lewatit MP62-WS. The loading capacity of the ion-exchange resins was increased 4 times approximately.
Audience take-away:
- This work shows a process to selectively remove chloride and uranium ions from a copper pregnant leaching solution, to improve the safety of the operation, by avoiding the accumulation of radioactive materials through the hydrometallurgical operation.
- The audience will be able to see an application of electrodialysis different than the conventional processes, applied to problems of the uranium industry.
- The results obtained in this project will allow to expand the possible applications of electrodialysis, to solve problems in various areas of the chemical industry.
