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.
Interaction mechanism between modified starches and aluminum-silicate minerals
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.