(中南大学 矿物工程系， 长沙 410083)
摘 要: 通过浮选实验、动电位和红外光谱测定，详细考察了变性淀粉在铝硅矿物浮选分离中的作用效果和机理。浮选实验显示：非离子淀粉和阴离子淀粉在pH＜6时，抑制一水硬铝石的浮选，但当pH＞6时，却对一水硬铝石浮选有活化作用；阳离子淀粉在较宽pH值范围内对一水硬铝石均有抑制作用；3种淀粉化合物在pH＜6时均活化高岭石的浮选，当pH＞6时活化作用较微。结果表明：变性淀粉是一水硬铝石型铝土矿反浮选中实现一水硬铝石和高岭石分离的有效调整剂，阴离子淀粉使矿物表面ζ-电位更负，阳离子淀粉使矿物表面ζ-电位更正，非离子淀粉使矿物表面电位绝对值减小。由实验结果结合药剂与矿物作用前后的红外光谱分析，得出结论：非离子淀粉主要通过氢键作用吸附于矿物表面，而静电力和化学键合力在阴离子淀粉和阳离子淀粉吸附中发挥着重要作用。
关键字: 变性淀粉； 铝硅矿物； 浮选； 作用机理
and aluminum-silicate minerals
（Department of Mineral Engineering， Central South University，
Changsha 410083， P.R.China）
Abstract: The interaction mechanism of modified starches in flotation separation of diaspore and kaolinite from bauxite has been investigated through flotation tests， zeta potential measurements and FTIR-DRIR. It is shown that non-ionic and anionic starches exhibit depressing effect on disapore at pH<6， but some activating effect at pH>6. The cationic starch depresses diaspore at wide pH region. On the other hand， three types starches have activation on the flotation of kaolinite at pH<6， and little effect at pH>6. Experiment has proved the modified starches are effective modifiers in reverse flotation separation of kaolinite from diaspore in diasporic-bauxite. The anionic starch makes the zeta potential of mineral surface become more negative and the cationic starch makes that of the surface more positive， the non-ionic starch decreases the absolute values of the zeta potential of diaspore and kaolinite. In the light of these results and FTIR-DRIR analyses， it is concluded that the adsorption of non-ionic starch on the diaspore and kaolinite is dominant by hydrogen bonding. Besides， electrostatic or chemical interactions may play more important role for the adsorption of cationic or anionic starch.
Key words: modified starch； aluminum-silicate mineral； flotation； reaction mechanism
