Crystallization behaviors of bayerite from sodium chromate alkali solutions  

铬酸钠碱性液中拜耳石的结晶行为(英文)

作　　者：魏广叶[1,2] 曲景奎[1] 郑裕东[2] 齐涛[1] 郭强[1] 韩冰冰[1] 赵宏欣[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]北京科技大学材料科学与工程学院,北京100083

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第10期3356-3365,共10页中国有色金属学报（英文版）

基　　金：Project(51125018)supported by the National Science Found for Distinguished Young Scholars of China;Project(2011BAC06B07)supported by the National Key Technologies R&D Program of China;Project(2011AA060704)supported by the National Hi-tech Research and Development Program of China;Projects(51204153,21106167)supported by the National Natural Science Foundation of China;Projects(2012M510552,2013T60175)supported by Financial Grant from the China Postdoctoral Science Foundation

摘　　要：In order to clean production of chromium compounds, it is a critical process to remove aluminates and utilize aluminum compounds from artificial chromate alkali solutions. The effects of Na2 Cr O4 on the neutralization curve, Al（OH）3 precipitation efficiency and induction period of bayerite were investigated. The results indicate that the neutralization curve of the artificial chromate alkali solutions shows three distinct regions and its induction period is longer than that of pure sodium aluminate solutions at the same aluminum concentration. And the decreased temperature and volume fraction of CO2 enhance the particle size of bayerite β-Al（OH）3. Bayerite composed of agglomerates of rods and cone frustums was obtained from alkali metal chromate solutions with 28.5% CO2（volume fraction） at temperatures ranging from 50 °C to 70 °C. Coarse bayerite with particle size（d50） from 24.2 μm to 29.3 μm extremely has few impurities, which is suitable for comprehensive utilization.铬酸钠碱性液中铝的脱除和铝化合物的利用是实现铬盐产品清洁生产的重要步骤。讨论铬酸钠对中和过程、氢氧化铝沉淀效率和氢氧化铝结晶诱导期的影响。结果表明：与高浓度铝酸钠相似,铬酸钠碱性液中铝酸钠的中和曲线也分为明显的3个区域。在相同铝浓度的溶液中,络酸钠碱性液中铝酸钠的诱导期比纯铝酸钠溶液的诱导期更长。温度和二氧化碳体积分数的降低有利于形成较为粗大的氢氧化铝颗粒。在温度为50~70°C,二氧化碳浓度为28.5%（体积分数）时,氢氧化铝主要为拜耳铝石型,由棒状和圆台状的聚集体组成。颗粒尺寸（d50）在24.2μm到29.3μm之间,杂质较少,有利于产品的综合利用。

关 键 词：chromate alkali solutions BAYERITE CARBONIZATION CRYSTALLIZATION precipitation efficiency 

分 类 号：TQ136.11[化学工程—无机化工]