【作者】 尹建国； 陈启元； 尹周澜；

【Author】 Yin Jianguo, Chen Qiyuan , Yin Zhoulan (College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)

【机构】 中南大学化学化工学院；

【摘要】 在拜耳法生产氧化铝过程中,要添加氢氧化铝晶种来促进过饱和铝酸钠溶液的分解。晶种的性质对过饱和铝酸钠溶液的分解具有很大的影响。本文对比研究了普通晶种和机械活化晶种对过饱和铝酸钠溶液分解过程的影响,实验结果显示:机械活化晶种粒度更小, 因而其比表面积更大,晶种与铝酸钠溶液之间的液固界面更大;机械活化晶种含有大量断裂面,新形成的断裂面活性大,因而氢氧化铝易于在活化晶种表面析出;采用活化晶种能大大提高了过饱和铝酸钠溶液的分解率及氢氧化铝粒子的附聚度;采用机械活化晶种的附聚产物形貌不规则且具有较高活性,有望通过进一步的晶体生长产生粒度、强度都符合规定的氢氧化铝。更多还原

【Abstract】 Crystal seeds of gibbsite are added into supersaturated sodium aluminate liquors in Bayer process in order to enhance the precipitation process. The properties of seeds have great effect on the precipitation process. The influence of normal seeds and mechanically activated seeds was investigated contrastively in the paper. Conclusions were made that mechanically activated seeds own larger specific surface areas and solid-liquid interface with sodium aluminate liquors because of its smaller particle size. Gibbsite precipitates easily on the mechanically seeds surface because that mechanically seeds have lots of new fracture planes of high activity. Precipitation ratio of supersaturated sodium aluminate and agglomeration ratio of gibbsite particles can be enhanced greatly by the addition of mechanically activated seeds. Agglomerates of mechanically activated seeds have irregular shape, which still have high activity and they can probably turn into gibbsite particles with satisfactory size and intensity by further crystal growth.更多还原