碱性溶液中坡缕石水解作用动力学实验研究

对安徽官山地区沉积型、热液型坡缕石进行碱性溶液中水解作用的动力学实验研究.结果表明:沉积型坡缕石较热液型更耐碱,且两种坡缕石均存在明显的差异溶解现象,即四面体硅的溶解速率要略大于八面体铝阳离子的溶解速率.碱溶液中沉积型、热液型坡缕石水解动力学均适宜采用圆柱体扩散控制模型模拟,其浸出率x对反应时间t的关系可表示为(1-x)+xlnx=kt.在实验条件下沉积型坡缕石水解过程中,Al3+和Si4+反应表观活化能分别为18.16 kJ/mol和18.53 kJ/mol.热液型坡缕石水解过程中,Al3+和Si4+反应表观活化能分别为31.2 kJ/mol和32.95 kJ/mol.

KINETICS OF HYDROLYSIS OF PALYGORSKITE IN ALKALINE SOLUTIONS

The kinetics of hydrolysis of deposited palygorskite and hydrothermal palygorskite in alkaline solutions was studied with elements analyzed by spectrophotometry. The results indicated that deposited palygorskite is more alkali-resistant to hydrothermal palygorskite. According to the process of palygorskite during solution in alkalescent environment and the results of study in the kinetic area, we can guestimate that there are different solutions during the process, that is to say, the velocity of tetrahedral silicon stripping is greater than that of octahedral cation stripping. The kinetics of hydrolysis of palygorskite should be described with the cylinder model in control. The relationship between leaching rate (x) and reaction time (t) can be expressed as (1-x)+xlnx=kt. The apparent activation energies of hydrolysis reaction of Al3+ and Si4+ are 18.16 and 18.53 kJ/mol for deposited palygorskite and 31.2 and 32.95 kJ/mol for hydrothermal palygorskite, respectively.