AlCl_3·6H_2O在Fe(Ⅲ)-K-Ca-Cl-H_2O体系中溶解度的测定

Solubility determination of AlCl_3·6H_2O in Fe(Ⅲ)-K-Ca-Cl-H_2O system

针对煤矸石酸浸提铝工艺中AlCl3·6H2O的结晶问题,采用静态法测定了25、50、70℃时AlCl3·6H2O在Fe（Ⅲ）-KCa-Cl-H2O体系中的溶解度。结果表明：在KCl-FeCl3-H2O、CaCl2-FeCl3-H2O和CaCl2-KCl-H2O体系中,AlCl3·6H2O的溶解度均随着温度的升高而有所增大;而在所测溶液浓度范围内（0-1mol/L）,固定其中一种溶液的浓度,AlCl3·6H2O的溶解度随着另一溶液浓度的增大皆不断减小,这是由氯离子的加入产生的同离子效应导致的。通过比较溶解度数据发现,溶液浓度是影响AlCl3·6H2O溶解度的主要因素,温度对AlCl3·6H2O溶解度的影响可忽略,这为AlCl3·6H2O的工业结晶过程的设计和优化提供了理论依据。

Based on the crystallization of AlCl3·6H2O in the acid-leaching filtrate of gangue,the solubility of AlCl3·6H2O in Fe（Ⅲ）-K-Ca-Cl-H2O system was measured by equilibrium method at 25-70 ℃.The experiment results show that the solubility of AlCl3·6H2O in all measured cases increases slowly with the increase of temperature.The solubility of AlCl3·6H2O decreases with increasing one of the solution concentrations for fixing the other of them in the KCl-FeCl3-H2O,CaCl2-FeCl3-H2O and CaCl2-KCl-H2O systems.This case might be ascribed to the common ion effect of added Cl-.It also can be shown that the concentration of solutions is the main factor for affecting the solubility of AlCl3·6H2O while the effect of temperature on the solubility can be ignored.This provides an important theoretical support for design and optimization of the industrial crystallization process of AlCl3·6H2O.