Abstract The depression effect of chitosan on talc as well as the associated mechanisms were investigated at different pH values. The flotation results showed that chitosan is a useful depressant for talc flotation and that its depression effect is independent of pH. The adsorption mechanisms of chitosan were different at pH 3 and 9. X-ray photoelectron spectroscopy analysis indicated that at pH 3 and pH 9, the chitosan adsorbed on talc surfaces through physical interactions. At pH 3, the adsorption changed the zeta potential of the talc from negative to positive and the adsorption was achieved via hydrogen bonding interaction. At pH 9, in addition to adsorption due to hydrogen bonding, the water-insoluble chitosan also deposited on the talc surfaces and shifted the slip surface of the electric double layer outward, thus making the surface potential of the talc gradually approach zero. The adsorbed chitosan could be washed away from the surface. This phenomenon occurred more easily at pH 3, because the deposited chitosan dissolved and entered the aqueous phase again. Flotation separation tests on the mineral mixtures indicated that the chitosan could only be used as a selective depressant for chalcopyrite and talc separation at pH 3.

中文翻译：

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pH值变化对壳聚糖抑制滑石粉的影响及相关机制

摘要 研究了壳聚糖在不同pH值下对滑石粉的抑制作用及其相关机制。浮选结果表明，壳聚糖是滑石浮选的有效抑制剂，其抑制作用与pH无关。壳聚糖的吸附机制在pH 3 和9 时不同。X 射线光电子能谱分析表明，在pH 3 和pH 9 时，壳聚糖通过物理相互作用吸附在滑石表面。在 pH 3 时，吸附将滑石的 zeta 电位从负变为正，吸附是通过氢键相互作用实现的。在 pH 9 时，除了由于氢键的吸附作用外，不溶于水的壳聚糖还沉积在滑石表面，使双电层的滑移表面向外移动，从而使滑石的表面电位逐渐趋近于零。吸附的壳聚糖可以从表面洗掉。这种现象在 pH 值为 3 时更容易发生，因为沉积的壳聚糖溶解并再次进入水相。矿物混合物的浮选分离试验表明，壳聚糖只能在 pH 3 时用作黄铜矿和滑石分离的选择性抑制剂。