粉煤灰盐酸浸出液酸分法结晶氯化铝的试验优化

Crystallization of Aluminum Chloride From Hydrochloric Acid Leaching Solution of Fly Ash

研究了采用酸分法,通过向净化后的粉煤灰盐酸浸出液中通入HCl气体结晶AlCl_3·6H_2O。试验结果表明:各因素对氯化铝结晶率的影响主次顺序为HCl气体通入速率>HCl气体通入量>结晶温度>静置时间;在HCl通入速率60mL/min、HCl通入量24.27L、结晶温度20℃、静置时间3h条件下,氯化铝结晶率达90.25%;降低HCl通入速率和增大通入量均有利于结晶率提高,当HCl气体通入速率低于45mL/min时,会发生倒吸,反之会导致返溶;结晶产物AlCl_3·6H_2O占98.7%,杂质主要为CaCl2·4H_2O、MgCl_2·2H_2O、FeClO。

Crystallization of AlCl3·6H2O from purified hydrochloric acid leaching solution of fly ash by bubbled into hydrogen chloride gas was researched. The results show that the order of influencing factors on crystallization of aluminum chloride is HC1 gas aeration rate〉HCl gas amount of inlet aeration〉 crystallization temperature 〉 standing time. The reducing HCI gas aeration rate and increasing amount of inlet aeration are favorable for crystallization of AlCl3·6H2O. Low aeration rate is more conducive to crystallize AlCl3·6H2O. HCl gas may reverse flow when it aeration rate is less than 45 mL/min,but AlCl3·6H2O crystal may re-dissolute when HC1 gas aeration rate is greater than 45 mL/min. Under the conditions of HCl gas amount of inlet aeration of 24. 27 L, aeration rate of 45 mL/min, standing time of 3 h and crystallization temperature of 20℃, the crystallization rate of AlCl3·6H2O is 90. 25% ,its purity is 98. 7% with minor impurities AlCl3·6H2O,AlCl3·6H2O and FeClO.