Study on the mechanism and thermodynamics of potassium leaching from phosphorus-potassium associated ore

Abstract

This paper has mainly focused on the technology of transforming potassium minerals from phosphate-potassium associated minerals into soluble potassium by acid hydrolysis, and discussed the leaching mechanism of potassium in the process of leaching. As it is shown from the research, in the acid leaching system, [H+] = 8.71 mol L–1, mNH4F:mphosphorushboxpotassiumassociatedore = 0.25, the leaching rate of potassium reaches 74% at 413 K for 2 h. And the release of potassium ion is the result of the interaction of “oxidation” and “ion exchange”. It was found from the Eh-pH diagram of K-(Si)-(P)-(F)-H2O system that, when P-F or Si-F appeared in K-H2O system, the K+ stable region became narrow, and the excess fluorine was not conducive to the stability of K+ in aqueous solution.