Preparation of Sub-micron α-Al₂O₃ Powders Using Aluminium Hydroxide as Raw Material

Aluminum hydroxides as raw material were calcined at 1 200,1 230,1 250,1 350,1 430 ℃ after pretreatment of washing.Sub-micron alumina were prepared after grinding for different periods of time.The effect of pretreatment of raw materials,calcination temperature and grinding time on the α-phase conversion rate,specific surface area and particle size of Al2O3.The results show that the pretreatment of raw material obviously reduced the content of Na2O in raw material,and then improved the conversion rate of α-phase and reduced the content Na2O in products.The optimum calcination temperature was 1 250 ℃,at which the α-Al2O3 of high conversion rate and good activity could be obtained,and particles were in sub-micron size after grinding for 8 h.