辉钼矿浮选体系中的界面热力学

Interface thermodynamics of molybdenite floatation system

通过辉钼矿浮选体系中矿物与水、捕收剂与水、矿物与气泡、矿物与捕收剂之间等一系列界面相互作用自由能的计算,对各界面之间的范德华力、疏水引力、水化斥力等界面热力学行为进行了研究。研究结果表明:各矿物表面与水之间均存在范德华引力和疏水引力,其中辉钼矿与水之间的疏水引力低于脉石矿物与水之间的疏水引力;捕收剂与水分子之间的疏水引力是导致捕收剂在水溶液中分散的主要作用力;辉钼矿与气泡之间的强疏水引力是辉钼矿具备天然可浮性的根本原因;水介质中辉钼矿与捕收剂之间的范德华力为引力,但范德华力不是辉钼矿与捕收剂之间的主要作用力,起捕收作用的主要因素是由Lewis acid-base(AB)相互作用造成的疏水引力。浮选实验结果表明:对于辉钼矿的浮选,捕收剂在矿物表面的吸附强度并不是影响其浮选指标的决定性因素,而捕收剂在水相中的分散能力以及捕收剂对矿物浮选的选择性对矿物浮选的影响较大。

The interface thermodynamics involving Van der Waals force, hydrophobic attractive force and hydration exclusive force were investigated by calculating the interracial interactive free energy of a series of interfaces such as minerals and water, collectors and water, minerals and bubble, minerals and collectors in the molybdenite floatation system. The results show that Van der Waals attractive force and hydrophobic attractive force exist in each minerals and water interface, the hydrophobic attractive force in molybdenite and water interface is remarkably weaker than that in gangue and water interface. The hydrophobic attractive force between molecule of collectors and water is the main force which causes the collectors to disperse in pulp. The strong hydrophobic attractive force between molybdenite and bubble interface is the basic reason which causes the natural flotability of molybdenite. In water solution, the Van der Waals force between molybdenite and collectors is attractive, but it is not the main force between them, the main factor resulting in collection is hydrophobic attractive force caused by the Lewis acid-base interaction. In molybdenite floatation system, the floatation experimental results show that the adsorption intension of collector on molybdenite surface is not the crucial factor, while the dispersing capability of collector in water phase and its selectivity for minerals floatation are more important.