By means of Malvern laser particle size analyzer and scanning electron microscopy, the influences of seed size and number on agglomeration in Bayer process were investigated. Agglomeration is almost finished in 8h, se...By means of Malvern laser particle size analyzer and scanning electron microscopy, the influences of seed size and number on agglomeration in Bayer process were investigated. Agglomeration is almost finished in 8h, seeds, below 5μm, especially below 2μm, gather together rapidly and almost disappear in 8h. In the same supersaturation of aluminate solution and seed size, the smaller the number of seed is, the bigger the degree of agglomeration is. With the same primary number of seed, the agglomeration of larger seed is superior to that of small seed, and the agglomeration does not happen among the coarse seeds. The agglomeration mainly happens among fine particles, and the combinations among the fine particles are unconsolidated.展开更多
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 investig...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.展开更多
基金Project(G19990649) supported by the National Key Fundamental Research and Development Programof China project(59874031) supported by the National Natural Science Foundation of China
文摘By means of Malvern laser particle size analyzer and scanning electron microscopy, the influences of seed size and number on agglomeration in Bayer process were investigated. Agglomeration is almost finished in 8h, seeds, below 5μm, especially below 2μm, gather together rapidly and almost disappear in 8h. In the same supersaturation of aluminate solution and seed size, the smaller the number of seed is, the bigger the degree of agglomeration is. With the same primary number of seed, the agglomeration of larger seed is superior to that of small seed, and the agglomeration does not happen among the coarse seeds. The agglomeration mainly happens among fine particles, and the combinations among the fine particles are unconsolidated.
基金Project(50804031) supported by the National Natural Science Foundation of China
文摘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.
