Research on the strengthening mechanism of potassium leaching process to potassium feldspar

Abstract

The technology of transforming potassium minerals from potassium feldspar into soluble potassium by acid hydrolysis, and discussed the leaching mechanism of potassium in the process of leaching. The results showed that the dissolution efficiency of potassium was 76 % under the conditions of 8.05 g·g−1 70 wt% H2SO4, 0.5 g·g−1 ammonium fluoride, 130 ± 2 °C and a reaction time of 2 h. The compound effect is much greater than the acid effect in the process of acid leaching. The ionization-hydrolysis model of potassium leaching is built, [K+] increases with the addition of [H+] and each side reaction coefficient. Without considering the precipitation effect of K2SiF6 and K3AlF6, [K+] is subjected to the joint action of [H+] and [F−]. When pH is constant, [K+] goes up as [F−] increases; when [F−] is constant, [K+] increases with the rise of [H+]. But the increase of [K+] in the solution intensifies the occurrence of side reaction of potassium, forming precipitation and decreasing the presence of soluble potassium in solution.