Abstract: The current classifier was used as purification equipment to remove the impurities of silica fume.The optimal condition of process were explored:1:2 liquid-solid ration,four times of classification.the content of silicon oxide increased by 4.65;.Meanwhile,the element composition,recovery ratio,size distribution and particle morphology of silica fume were analyzed.The result shows that the content of C element reduces from 4.5; to 0.4;,removal rate over 90;,other impurity elements that in form of silicate or oxide are not removed;in optimal experimental condition,recovery ratio is 84.5;;average particle size increased from 0.334 μm to 0.557 μm;small particle were removed and particle size becomes more uniform,and the silica particle keep the original smooth spherical morphology.This is a green,environmental friendly waste recycle method which has small energy consumption and no change to the morphology,compared to the roasting process.

Key words: The current classifier was used as purification equipment to remove the impurities of silica fume.The optimal condition of process were explored:1:2 liquid-solid ration,four times of classification.the content of silicon oxide increased by 4.65;.Meanwhile,the element composition,recovery ratio,size distribution and particle morphology of silica fume were analyzed.The result shows that the content of C element reduces from 4.5; to 0.4;,removal rate over 90;,other impurity elements that in form of silicate or oxide are not removed;in optimal experimental condition,recovery ratio is 84.5;;average particle size increased from 0.334 μm to 0.557 μm;small particle were removed and particle size becomes more uniform,and the silica particle keep the original smooth spherical morphology.This is a green,environmental friendly waste recycle method which has small energy consumption and no change to the morphology,compared to the roasting process.