Facile activation of lithium slag for the hydrothermal synthesis of zeolite A with commercial quality and high removal efficiency for the isotope of radioactive 90Sr

Abstract

With the quick development of the lithium industry, large amounts of solid waste of lithium slag are produced. Making high value-added products from lithium slag can not only alleviate environmental problems but also improve resource utilization efficiency. However, the success of converting the lithium slag to valuable products is very limited. Herein, we reported a mild activation method for lithium slag and the synthesis of highly crystalline zeolite A with high sorption capacity (246.9 mg g⁻¹), fast sorption kinetics (reaching sorption equilibrium within 5 minutes), wide working pH (4–13) and excellent selectivity for the isotope of radioactive ⁹⁰Sr from aqueous solution. The obtained zeolite A has a static water absorption capacity of 26.1 wt%, which is higher than the standard of the first-class grade of zeolite A in GB 6287-86, a Chinese national standard for commercial zeolite A. We also comprehensively investigated the evolution of the species during the activation of lithium slag, the crystallization field of zeolite A, the crystallization process of zeolite A under optimal conditions and the influence of various factors on the sorption of Sr²⁺ from aqueous solution.