Study On Application Of Grinding Aids In Grinding Of Henan Low Grade Bauxite

The dissemination characteristic and effects of different grinding conditions on grinding of Henan low grade bauxite was studied in this thesis. The effects of different reagents on promoting effect and selective grinding were studied. The mechanisms of grinding aids have been studied by measurements of Zeta potential, FTIR et al.As known from the dissemination characteristic, the crystal structure of diaspore is compact, and it possess the close relationship with the dissemination of silicon gangue minerals such as kaolinite,illite. The dissemination characteristic of diaspore determined the grinding granularity. Meanwhile, the crushing behavior and selective grinding are also impacted by the rigidity,liberation and the structure defect of the ore.The grinding condition and grinding aids addition experiments show that the steel ball size and size ratio,grinding time and grinding concentration et al. has great impaction on grinding of bauxite; Sodium carbonate,calgon and RC have better promoting effect on grinding of bauxite. Compared with no addition of reagent, when the grinding concentration is 80%, the contents of -0.075mm particles respectively increased 9.23%,11.47%,9.74%. The A/S analysis indicated that the A/S of the coarse size fraction in the grinding product improved when adding the reagents. So, the enhancing effect of the used reagents is obvious in selective grinding.The study on the mechanisms of grinding aids indicated that the surface Zeta potential was changed by adding sodium carbonate,calgon and RC, and thus lead to the modification of the pulp rheology characteristic and the improvement of grinding efficiency. At the same time, the improvement of pulp rheology characteristic decreased the screen and catalyzes effects between soft and hard minerals, strengthen the selective grinding of the bauxite. For the difference of the crystal structure between diaspore and aluminum-silicon minerals, reagent absorbed on the mineral surface, which lead to the cracked aluminum-silicon minerals are easier crush, and strengthened the selective grinding. The SEM result showed that surface roughness of bauxite mineral were changed through the addition of calgon, which are in favor of the pulp rheology characteristic alteration; and the particle surface did not exist obvious crack and interspace, which indicate the adsorption of calgon on mineral surface reduced the surface energey, and promote the flaw crack break. XRD analysis showed that the addition of urea may accelerate crushing through intercalation, thus strengthen the selective grinding of bauxite.