The Research On Application Of Grinding Aids In Selective Grinding Of Bauxite

Bauxite is raw material of producing alumina, refractory material and building material. Most of bauxite of our country is the type of diaspore, which contain much of aluminium and silicon and less of iron. The total reserve is 99 percent of the all reserve of bauxite. The Al/Si exceeding 10 is no more than 10%, and it is difficult to wash and process the ore, so that it can't be used to produce alumina with the routine Bayer process. Now efforts are having been maken to develope method and technics of desiliconing by mineral processing.Tests have been done using grinding aids to improve grinding efficiency and increase Al/Si with bauxite from Henan Province as raw material, through which diaspore can be selectively separated from kaolinite under coarse grinding size . So the coarse product has high Al/Si which can be used by Bayer process and the fine fraction is feeded to flotation.This research selects a variety of grinding aids which includes (NaPO₃)₆, NaOH, citric acid anhydrate, DA, DC-40 and DC(Z-16), to study the effects of the type and amount of aids on the selective grinding of bauxite under different conditions, on which the suitable aid and its optimum amount can be determined.The results show that the effect of DA, DC-40, DC(Z-16) and (NaPO₃)₆ on the selective grinding bauxite is significant, the yield under 200 mesh in grinding product can be improved by 7.88%, 7.54%, 7.47%, 7.62% compared with product without addings, the corresponding best amount of addings is 0.5%, 1%, 0.5%, 0.2% respectively. In addition, the yields of Al/Si exceeding 9 are increased by 24.62%, 23.17%, 24.17%, 9.87% respectively, which the separation is intensified, i.e., Al₂O₃ is...