Desilication Of Low Alumina-Silica Ratio Bauxite By"Selective Grinding-Aggregation Flotation" Process

"Selective grinding-aggregation flotation" process used in desilication practices of low alumina-silica ratio bauxite was investigated in this dissertation, in order to improve utilization status of low alumina-silica ratio bauxite in Henan and Shanxi Province.It is one point of "selective grinding-aggregation flotation" process that coarse materials are pre-classified from grinding product as a part mixed concentrate product. The rationality of that process is based on the fact that the recovery of coarse particle is very low and selective grinding nature of bauxite.Experimental results show that the best size boundary of pre-separation is0.075mm. The coarser is the size boundary of pre-separation, the higher is the yield and Al/Si of mixed concentrate when it is finer than0.075mm; The coarser is it, the lower is the yield of mixed concentrate, and the higher is the Al/Si of mixed concentrate when it is coarser than0.075mm.Closed-circuit test was conducted under optimum conditions with raw of2.82Al/Si and with the concentrate obtained of5.90Al/Si in a yield of66%, under which-0.075mm materials content was84%, pulp density was27%, pH of roughing was9.4, pH of cleaning was9.8, dosage of sodium hexametaphosphate was40g/t, dosage of collector was1OOOg/t, and stirring time was1Omin.Hydro-cyclone was used as classification equipment in the pre-separation process in Dongda dressing plant. The mixed concentrate of6.20Al/Si was obtained in a yield of59.80%which was10%higher than before, when the yield of coarse product of4.42Al/Si was21.77%."Selective grinding-aggregation flotation" process is superior in desilication practices of low alumina-silica ratio bauxite.