Desilication Of Bauxite With High-Silicon And High-Iron In Wenshan

In order to eliminate the detrimental effect of iron on bauxite and raise the A/S ratio by separating iron and silicon-bearing minerals from the high-iron and high-silicon bauxite, respectively. The effects of different factors on desilication of bauxite were firstly studied by the flotation and dissolution experiments of pure minerals. Then the structure and property of raw ore were studied by means of optical microscope, scanning electro-microscope, XRD, multi-elements analysis and chemical phase analysis. At last, the pre-desilication of bauxite was analyzed by dynamic analysis, solution chemistry calculation and zeta potential test.The results of this work can provide theoretical guideline for removing iron and desilication of real bauxite.The results of dissolution experiments of pure minerals are shown as follows. The high-temperature can raise the dissolved rates of kaolinite, and the A/S ratio increased with the increase of temperature. The dissolved rates of kaolinite also can be increased by increasing liquid-solid ratio, and thereby A/S ratio can be raised by increasing liquid-solid ratio. The increase of alkali results in the increase of OH" activity which promotes the dissolution of kaolinite and lastly A/S ratio can be raised. The agitation which in favor of the dissolution of silicon can make up for the inadequacy of the respects such as concentration of alkali, temperature and so on. Factors above have little effect on the dissolved rates of diaspore.The results of flotation experiments of pure minerals are shown as follows. The sodium oleate which used as a kind of collector has stronger effect on diaspore than kaolinite in the flotation process and the optimum pH ranges8to10. The recovery of diaspore decreased for multi-layer adsorption of sodium oleate on the surface of diaspore. Therefore, the concentration of sodium oleate should not exceed4X10-4mol/L Temperature have an important effect on activity of sodium oleate, so the temperature should be above20℃. The diaspore can be collected while kaolinite can not be collected by BAC. The kaolinite can be separated efficiently from diaspore when sodium oleate mixed with BAC in the proportion of9:1. The sodium carbonate is a effective regulator and disperser. The diaspore and kaolinite can be depressed by sodium hexametaphosphate which can increase the difference of floatability between diaspore and kaolinite and thereby improve the separation effect in a certain amount.The results of experiments of real ore are shown as follows. The iron can be removed efficiently from bauxite by magnetic separation. The recovery and grade of iron are42.71%and42.15%on conditions of grinding time15min and magnetic intensity1.5T. The dissolved rate of silica can reach42%. A/S ratio can rise from2.52to5.03.Meanwhile A/S ratio can be increased to5.87by flotation and concentrate recovery is54.26%.