Crystallization of gibbsite from synthetic chromate leaching solution in sub-molten salt process  

亚熔盐法铬酸盐模拟浸出液中三水铝石的结晶行为（英文）

作　　者：张培育[1,2] 魏广叶[1] 郭强[1] 曲景奎[1] 齐涛[1] 

机构地区：[1]中国科学院过程工程研究所湿法冶金清洁生产技术国家工程实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第8期2734-2743,共10页中国有色金属学报（英文版）

基　　金：Project(51125018)supported by the National Science Foundation for Distinguished Young Scholars of China;Project(2011AA060704)supported by the National High-tech Research and Development Program of China;Projects(51204153,21406246)supported by the National Natural Science Foundation of China

摘　　要：For the clean and economical production of chromium compounds, it is crucial to remove aluminates from chromate alkali solutions and utilize aluminum-containing compounds. In this work, carbonization was used to remove aluminates from a synthetic chromate leaching solution containing a high K2O/Al2O3 mole ratio. The influence of reaction temperature, carbonization time, flow rate of carbon dioxide, and seed ratio on the precipitation of Al was investigated. The optimal output was obtained under the following experimental conditions： a reaction temperature of 50 °C, a carbonization time of 100 min, a carbon dioxide flow rate of 0.1 L/min, and a seed ratio of 1.0. Gibbsite was obtained following carbonization. The structure and morphology of the gibbsite were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and laser particle size analyzer. The particle size distribution and morphology of the gibbsite were significantly influenced by the experimental conditions. The gibbsite had a mean particle size （d50） of 16.72μm. The thermal decomposition of the gibbsite was analyzed by XRD and the decomposition path was determined. The obtained coarseα-Al2O3 precipitate, which contains 0.08% Cr2O3 and 0.10% K2O, was suitable for subsequent utilization.除去铬酸钾溶液中的铝并实现铝化合物的再利用是实现清洁、经济地生产铬盐的关键步骤。采用碳分的方法从配制的高K2O/Al摩尔比铬酸钾溶液中去除铝。考察反应温度、碳分时间、CO2流量、晶种系数对铝沉淀率的影响。优化反应条件为:反应温度为50°C,碳分时间为100 min,CO2流量为0.1 L/min,晶种系数为1.0。碳分产物为三水铝石。采用X射线衍射仪、扫描电镜和激光粒度仪对产物的结构和形貌进行表征。实验结果表明,产物的粒度和形貌受实验条件影响明显。产物的平均粒径为16.72μm。对三水铝石的热分解路径进行研究。产物α-Al2O3含少量杂质(0.08%Cr2O3和0.10%K2O),适于后续利用。

关 键 词：GIBBSITE secondary nucleation CARBONIZATION chromate leaching solution 

分 类 号：TQ136.11[化学工程—无机化工]