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铝土矿正浮选实践中,常采用脂肪酸阴离子捕收剂(如油酸)选择性分离一水硬铝石和高岭石等铝硅酸盐矿物。矿物表面晶体化学特性是产生选择性浮选分离的决定性因素。笔者研究了油酸钠(Na OL)浮选体系中一水硬铝石和高岭石的可浮性,发现一水硬铝石可浮性明显好于高岭石。红外光谱分析表明,矿物表面Al质点与油酸的羧酸基团发生化学吸附作用。借助Materials Studio软件分别计算了2种矿物常见晶面的单位面积断裂键数,并计算了矿物晶面/捕收剂的作用能。计算分析发现,矿物晶面单位面积断裂键数以及与油酸根离子相互作用能大小存在差异,具体为:一水硬铝石(100)>(001)>(010),而高岭石(010)>(110)>(001),而且油酸与一水硬铝石3个晶面的的作用皆强于高岭石。矿物晶体晶面的Al-O断裂键数不同导致油酸作用下高岭石和一水硬铝石的可浮性差异。
In bauxite flotation practice, fatty acid anion collectors such as oleic acid are often used to selectively separate aluminosilicate minerals such as diaspore and kaolinite. Crystallographic chemical properties of mineral surfaces are a decisive factor in the selective flotation separation. The author studied the floatability of diaspore and kaolinite in sodium oleate (Na OL) flotation system and found that the buoyancy of diaspore is obviously better than that of kaolinite. Infrared spectroscopy showed that the Al sites on the mineral surface chemically adsorbed the carboxylic acid groups of oleic acid. With the help of Materials Studio software, the number of fracture bonds per unit area of two kinds of common crystal planes were calculated and the action energy of mineral crystal planes / collectors was calculated. Computational analysis shows that there are differences in the number of fractured bonds per unit area of the mineral crystal plane and the interaction energy with the oleate ions, specifically: diaspore (100)> (001)> (010), and kaolinite )> (110)> (001), and the effect of oleic acid and diaspore planes are stronger than that of kaolinite. The differences of buoyancy between kaolinite and diaspore under the action of oleic acid due to the different numbers of Al-O bond in the crystal plane of the mineral crystal.