Adjustment on gibbsite and boehmite co-precipitation from supersaturated sodium aluminate solutions  

作　　者：王志 杨柳 张娟 郭占成 张懿 

机构地区：[1]National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,Institute of Process Engineering,Chinese Academy of Sciences [2]Graduate University of Chinese Acade my of Sciences

出　　处：《Transactions of Nonferrous Metals Society of China》2010年第3期521-527,共7页中国有色金属学报（英文版）

基　　金：Projects(50704030) supported by the National Natural Science Foundation of China;Project(KGCX2-YW-321-2) supported by the Knowledge Innovation Program of the Chinese Academy of Sciences

摘　　要：Gibbsite is the usual precipitation product from alumina refineries with either Bayer or sintering process.However,the advantage of boehmite precipitation over gibbsite precipitation is the significant energy saving in the subsequent calcination step.The current investigation takes a pragmatic approach to measure precipitation ratios,determine product phase,morphology and particle size distribution,and assess the impacts and adjustment capability of main parameters such as seed,temperature,ethanol medium,and supersaturation on the precipitation kinetics and alumina hydrate type during co-precipitation process.The results clarify that gibbsite and boehmite both can be precipitated from supersaturated sodium aluminate solutions simultaneously,and the competitive formation between Al(OH)3 and γ-AlOOH determines the main precipitate phases from pregnant liquor.Boehmite seeds,high temperature and ethanol addition can promote the boehmite precipitation and improve the mass fraction of boehmite in products.Co-precipitation changes the multimodal distribution of seeds to a normal and well distribution of products,and the particle size is more than several times that of seeds.Gibbsite is the usual precipitation product from alumina refineries with either Bayer or sintering process.However,the advantage of boehmite precipitation over gibbsite precipitation is the significant energy saving in the subsequent calcination step.The current investigation takes a pragmatic approach to measure precipitation ratios,determine product phase,morphology and particle size distribution,and assess the impacts and adjustment capability of main parameters such as seed,temperature,ethanol medium,and supersaturation on the precipitation kinetics and alumina hydrate type during co-precipitation process.The results clarify that gibbsite and boehmite both can be precipitated from supersaturated sodium aluminate solutions simultaneously,and the competitive formation between Al（OH）3 and γ-AlOOH determines the main precipitate phases from pregnant liquor.Boehmite seeds,high temperature and ethanol addition can promote the boehmite precipitation and improve the mass fraction of boehmite in products.Co-precipitation changes the multimodal distribution of seeds to a normal and well distribution of products,and the particle size is more than several times that of seeds.

关 键 词：sodium aluminate solutions CO-PRECIPITATION BOEHMITE GIBBSITE 

分 类 号：TF821[冶金工程—有色金属冶金]