Study On Strengthening Dispersion And Flotation Test Of Low Grade Bauxite

Low-grade bauxite of 2.7 A/S of Henan Dengfeng area was researched in this paper.Improve the floatation result of bauxite by the test of strengthening dispersion.The process mineralogy of experiment samples were analyzed. Alumina content of 52.33% and silica content of 19.55% in the ore sample, and the Al-Si ratio is 2.68. Useful mineral in the ore is diaspore, whose content is 38.35%, while kaolinite, illite, clay minerals is gangue minerals.Disseminated relationships of diaspore and kaolinite, illite, quartz are complex. To achieve effective dissociation, the ore must be finely ground. The content of fine particles increased significantly in fine grinding process, which would be detrimental to the dissociation of mineral particles and conjunction of mineral particles and agents in flotation process.On the basis of the analysis of process mineralogy, laboratory tests of strengthened dispersion of low grade bauxite were carried out. The effects of stirring speed-stirring time,p H, dispersing agents(sodium silicate, phosphate, compound dispersant macromolecules starch), metal ions(Ca2+, Mg2+, Fe2+, Al3+, Fe3+) and concentration on bauxite dispersion were investigated. At p H 10, sodium hexametaphosphate dosage 40mg/L, the dispersion rate of bauxite is 46.99%. By examining the effects of p H, metal ions, sodium carbonate,sodium hexametaphosphate, etc. on the surface potential of bauxite, the relationship between bauxite dispersion and surface zeta potential was analyzed. The results showed that the larger the absolute value of zeta potential in bauxite surface, the larger the electrostatical free energy between the particles and the stronger the effect of bauxite dispersion.Laboratory flotation tests were carried out based on the dispersion test. The results showed that in one roughing circuit of adding 3000g/t sodium carbonate and 40g/t hexametaphosphate, the dispersing rate increased to 49.11%. The flotation index of 4.29A/S and 77.07% Al2O3. Ca2+ and Mg2+ have a relatively effect.The high concentrations of Ca2+and Mg2+inhibit the dispersion of bauxite. One roughing-two concentrating open circuit, when low grade bauxite of 2.82 A/S,the flotation index of 6.47 A/S and 59.76%Al2O3 recovery of the concentrate were obtained. Under one rough and two fine closed processes, the flotation index of 6.05 A/S and 69.67% Al2O3 recovery of the concentrate were obtained.