| Abstract The effects of Fe 3+ ,Al 3+ and Mg 2+ on the crystal habits of gypsum in wet phosphoric acid in the absence of F - were studied in a continous MSMPR crystallizer.The results of the experiments showed that the crystals of Gypsum were of meedle shape no matter whether the free excess of SO 2- 4 was 2 4% or 4 8%.When the concentrations of SO 2- 4 and the other two corresponding impurities were kept constant,the crystal length of gypsum increased with the increase of Fe 3+ content;the crystal size of gypsum decreased with the increase of Mg 2+ content and increased with the increase of Al 3+ content.The presence of F - and Al 3+ would promote the formation of aggregating crystal. |
|
1997, Vol. 14 
