(中南大學(xué) 礦物工程系， 長(zhǎng)沙 410083)
摘 要: 通過(guò)浮選實(shí)驗(yàn)、動(dòng)電位和紅外光譜測(cè)定，詳細(xì)考察了變性淀粉在鋁硅礦物浮選分離中的作用效果和機(jī)理。浮選實(shí)驗(yàn)顯示：非離子淀粉和陰離子淀粉在pH＜6時(shí)，抑制一水硬鋁石的浮選，但當(dāng)pH＞6時(shí)，卻對(duì)一水硬鋁石浮選有活化作用；陽(yáng)離子淀粉在較寬pH值范圍內(nèi)對(duì)一水硬鋁石均有抑制作用；3種淀粉化合物在pH＜6時(shí)均活化高嶺石的浮選，當(dāng)pH＞6時(shí)活化作用較微。結(jié)果表明：變性淀粉是一水硬鋁石型鋁土礦反浮選中實(shí)現(xiàn)一水硬鋁石和高嶺石分離的有效調(diào)整劑，陰離子淀粉使礦物表面ζ-電位更負(fù)，陽(yáng)離子淀粉使礦物表面ζ-電位更正，非離子淀粉使礦物表面電位絕對(duì)值減小。由實(shí)驗(yàn)結(jié)果結(jié)合藥劑與礦物作用前后的紅外光譜分析，得出結(jié)論：非離子淀粉主要通過(guò)氫鍵作用吸附于礦物表面，而靜電力和化學(xué)鍵合力在陰離子淀粉和陽(yáng)離子淀粉吸附中發(fā)揮著重要作用。
關(guān)鍵字: 變性淀粉； 鋁硅礦物； 浮選； 作用機(jī)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
