工艺参数对两种贵州高铝矾土烧结性能的影响

Influences of process parameters on sintering properties of two bauxites from Guizhou

将Al2O3含量(w)分别约为78%和81%的两种贵州高铝矾土原矿破碎、湿法球磨、压制成型并煅烧,探讨了球磨时间、煅烧温度和保温时间对其烧结性能的影响。结果表明:本试验条件下的破碎和球磨等机械作用只能将矾土矿中的一水铝石鲕状体分开,而很难将已分开的一水铝石单体继续粉碎。高铝矾土经均化处理(破碎至一水铝石单体粒径,再湿法球磨0.5 h)后,在1 600℃下煅烧1 h可获得良好、稳定的烧结性能,主要物相为刚玉和钛酸铝;延长保温时间,刚玉晶体长大,微小气孔消失,但对显气孔率影响不大;在烧结过程中,Fe2O3和TiO2与Al2O3固溶,而Fe2O3的固溶并不会改变原钛酸铝的晶体结构。

Two kinds of bauxites（w（Al2O3） is about 78% and 81%,respectively） were crushed,wet ball milled,pressed into shape,and calcined.Influences of ball milling time,calcination temperature and soaking time on sintering properties of the specimens were discussed.The results show that：（1）under this test condition,mechanical action such as crushing and milling can only separate the monohydrate bauxite oolites but can hardly make further pulverization on the single oolite;（2）when the bauxites are homogenized（crushed to powders with particle size closing to the single monohydrate bauxite oolite and wet ball milled for 0.5 h） and fired at 1 600 ℃ for 1 h,favorable and stabile sintering properties are obtained with main phases of corundum and aluminium titanate;（3）crystal grain size of corundum increases and micropores disappear,but apparent porosity changes a little when the soaking time at 1 600 ℃ is prolonged;（4）Fe2O3,together with TiO2,form solid solution with Al2O3 during sintering process,however,the solid solution of Fe2O3 can not change the crystal structure of aluminium titanate.