铁离子淀粉配合物在某铁矿石反浮选中的抑制行为及机理

将苛性淀粉溶液和三价铁离子溶液调配成铁离子淀粉配合物溶液,以其和苛性淀粉为抑制剂,考察他们在铁矿石反浮选中对铁矿物的抑制性能,并从动电位和红外光谱角度分析了抑制剂与赤铁矿和石英的作用情况。试验表明:(1)铁离子淀粉的抑制能力和选择性皆优于苛性淀粉。(2)在矿浆p H为中性、铁离子淀粉用量为1 000 g/t、十二胺用量为400 g/t情况下,采用1次粗选流程处理铁品位为20.50%的巴西某矿石,可得到铁品位为46.79%、铁回收率为79.36%的铁精矿,该指标明显优于苛性淀粉用量为1 000 g/t时的指标。(3)动电位测试表明,铁离子淀粉和苛性淀粉对赤铁矿都有较强的吸附作用,使赤铁矿动电位负值增大,但铁离子淀粉对石英表面动电位的影响明显小于苛性淀粉,因而铁离子淀粉在浮选中表现出更好的选择性抑制效果。(4)红外测试表明,铁离子淀粉中淀粉分子主要通过C=O与铁离子发生配位作用,同时也存在一定的氢键作用,β-Fe OOH特征吸收峰的出现,说明铁离子淀粉可能是以β-Fe OOH为胶核,淀粉分子通过配位和氢键作用吸附在胶核表面形成配合物,对十二胺在赤铁矿表面吸附具有更强的空间阻碍作用,抑制性能更好。

Study on Depressing Effect and Mechanism of Ferric-starch Complex in Reverse Flotation of an Iron Mine

The ferric-starch complex solution,synthesized by mixing ferric ion solution with caustic starch solution,was used as the flotation depressant to investigate its depressing effect on iron ore reverse flotation along with the caustic starch. Their effects on hematite and quartz were analyzed by zeta potential and infrared spectrum tests. The results of cationic reverse flotation showed that:①both depressing ability and selectivity of ferric-starch were better than that of the caustic starch.②un-der conditions of neutral pulp pH,ferric-starch content of 1000 g/t,Dodecylamine dosage of 400 g/t,iron concentrate with Fe grade 46. 79% and Fe recovery of 79. 36% from a iron ore with Fe grade of 20. 50% in Brazil was obtained by the process of 1 roughing. This index was significantly higher than caustic starch at the dosage of 1000 g/t.③Zeta potential tests showed that both ferric ion starch and caustic starch have a strong adsorption effect on hematite,and improve the zeta potential of hematite. But ferric ion starch has a weaker impact on zeta potential of quartz than that of caustic starch,therefore,the ferric ion starch shows a better selective inhibition effect in flotation.④ Infrared spectrum tests showed that the starch molecular in ferric ion starch mainly takes a coordination effect with iron ion through C=O,but also occurs a hydrogen bonding effect. Whereas,the appearance of the absorption peak of β-FeOOH suggests that based onβ-FeOOH pectin core, starch molecules of ferric ion starch is absorbed on surface of pectin core to form a complex through coordination and hydrogen bonding effect. The complex has a stronger steric hindrance effect of Dodecylamine on hematite surface,with a better suppression performance.