中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 20 No. 3 March 2010 |
seeded sodium aluminate solution
(1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China;
2. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China)
Abstract:Periodical attenuation of particles, which interferes seriously the normal alumina production, exists in Bayer process. In order to solve this problem, the rule of periodical attenuation of Al(OH) 3 particles was investigated by laboratory experiments under simulated industrial conditions. The results show that at higher temperature the variation period of particle size is shortened, while prolongs with more solid content. Particle size fluctuation amplitude reduces with the temperature rising but increases with the solid content increasing. Particle size distribution becomes more uniform by replenishing fine seeds, enabling the periodical fluctuation of Al(OH)3 particle size to be attenuated. Combining properly the additives with controlling the seed size is able to reduce the amplitude of periodical fluctuation and shorten the attenuation time. With unbalance of particle size distribution, the particles gradually become bigger, even inducing the decrease of the specific surface area of seeds, which is the major reason causing explosive attenuation of Al(OH)3 particles in seed precipitation process.
Key words: Bayer process; sodium aluminate solution; periodical attenuation; additive; seed precipitation