钙离子体系下羧化壳聚糖对滑石浮选行为影响

Effect of carboxylation chitosan on flotation behaviors of talc in presence of calcium ions

通过滑石纯矿物实验,考查钙离子作用下羧化壳聚糖对滑石可浮性影响。结果表明:滑石天然可浮性较好,在pH值为2～12时以MIBC为起泡剂进行浮选,回收率均在90%以上;酸性条件下(p H<5)羧化壳聚糖对滑石的抑制效果显著,随着pH值的升高羧化壳聚糖对滑石的抑制能力逐渐减弱。而钙离子作用时,碱性条件下羧化壳聚糖对滑石的抑制效果显著。结合吸附量和Zeta电位测试,溶液化学计算表明,在碱性条件下钙离子溶解组分以Ca^(2+)和Ca(OH)^+的形式吸附在荷负电的滑石表面,并在滑石表面产生钙位点,减小滑石与羧化壳聚糖之间的静电斥力,促进羧化壳聚糖在滑石表面吸附,实现羧化壳聚糖在弱碱性条件下对滑石的抑制。

The effect of carboxylation chitosan on the flotation behaviors of talc in the presence of calcium ions was investigated by micro-flotation tests. The flotation results show that the flotation recovery of talc is above 90% in the pH range of 2？11 using MIBC alone. The inhibiting effect of carboxylation chitosan is significant on talc flotation below pH 5, but is decreased in alkaline condition as the pH rose. When the talc is pretreated by calcium ions, the inhibiting effect of carboxylation chitosan on talc flotation in alkaline condition is significant. Combined with the results of absorption tests, zeta potential and solution calculation of calcium ions, it is indicated that the Ca2＋ and Ca（OH）＋ dissolved species of calcium ions absorbe on the negative surface of talc in alkaline condition, and generate calcium-binding sites, then decrease the electrostatic repulsion between talc and carboxylation chitosan, and improve the absorption of carboxylation chitosan on talc surface, thus depresse the talc under the condition of alkalescence.