关键词: 钾长石, 亚熔盐, NaOH, 钾离子, 溶出, 分解

Abstract: High concentration NaOH sub-molten salt was used to decompose potassium feldspar powder. The effects of the particle size, concentration of NaOH, stirring speed, reaction time, reaction temperature and mass ratio of liquid to solid on the dissolution rate of K+ were studied. The optimum reaction conditions were obtained for 100 mm diameter potassium feldspar powder, that is, NaOH initial concentration 60%(w), reaction temperature about 160℃, stirring speed 400 r/min, and mass ratio of liquid to solid 4:1. After 140 min reaction, the dissolution rate of K+ was over 98%(w). The decomposition kinetics of potassium feldspar powder under the reaction conditions was studied. The decomposition rate of potassium feldspar powder was in accordance with the shrinking core model at constant particle size. The reaction was controlled by the internal diffusion through ash layer in the initial stage of reaction. The kinetic constants were estimated, and the apparent activation energy was 110.42 kJ/mol at the temperatures of 80~140℃.

Key words: potassium feldspar, sub-molten salt, NaOH, potassium ion, dissolution, decomposition