Effects of silica and ferric oxide on crystallization of sodium aluminate

The effects of silica and ferric oxide on crystallization of sodium aluminate were studied and explained theoretically in this paper.When the concentrations of silica and the ferric oxide in the sodium aluminate solution increase but other conditions remain invariable,the crystallization ratio of sodium aluminate reduces sharply.When the concentration of silica increases from 0 g/L to 20g/L,the crystallization ratio of sodium aluminate drops by 33.6%,and the structure of the sodium aluminate crystal changes from compact to loose and porous.When the concentration of ferric oxide increases from 0 g/L to 4g/L,the crystallization ratio of sodium aluminate drops by 12.5%,and the structure of the sodium aluminate crystal change from compact to leptosomatic shape and finally gradually to irregular block.By SEM and FTIR technology the reason for the dropping of the sodium aluminate crystallization ratio has been found.The existence of silica changes the structure of aluminate ion,and the existence of ferric oxide increases the suspended solid concentration in the sodium aluminate solutions.Thus the aluminate ion can't agglomerate easily and the sodium aluminate solution remains stable.