NaOH亚熔盐法分解钾长石矿

以高浓度NaOH溶液为亚熔盐介质分解钾长石矿精粉，考察了矿物粒径、NaOH溶液浓度、搅拌速度、反应时间、反应温度、液固比对K+溶出率的影响，并对分解过程动力学进行分析. 结果表明，100 mm粒径钾长石矿精粉的最佳反应条件为：NaOH初始浓度60%(w)、反应温度约160℃、搅拌速度400 r/min、液固质量比4:1、反应140 min，该条件下K+溶出率大于98%. 钾长石的分解符合粒径恒定的缩核模型，反应初期固相产物层内扩散为速控步骤. 80~140℃下，反应的表观活化能为110.42 kJ/mol.

Decomposition of Potassium Feldspar by NaOH Sub-molten Salt Method

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℃.