巯基乙酸抑制硫化矿物的电化学机理研究

研究了巯基乙酸（TGA）对硫化矿物电极电位和动电位的影响。试验表明巯基乙酸对黄铁矿、方铅矿和黄铜矿有抑制作用，对毒砂和亲锌矿没有抑制作用。电化学测试表明巯基乙酸对表面覆盖有捕收剂膜的硫化矿物动电位影响较小，能够显降低硫化矿物的静电位，它对硫化矿物抑制的电化学机理为当硫化矿物的静电位EMS低于黄药氧化为双黄药的可逆电位EX^-/X2时，硫化矿物表面双黄药不稳定被还原，从而降低了可浮性；反之，双黄药保持稳定，不被抑制。用巯基乙酸实现两种硫化矿物浮选分离的电化学条件为：EMS1＜EX^-X2(EX^-/GPbX2）＜EMS2。

Electrochemical Mechanism on Interaction of TGA with Sulphide Minerals

The effects of TGA (thioglycollic acid) on the rest potential and zeta potential of sulphide minerals have been studied in this paper. Test results show that galena, pyrite and chalcopyrite can be depressed well by TGA, but sphalerite and arsenopyrite can not be depressed. Tests show that TGA has a less influence on zeta potential of sulfide minerals covered by xanthate coantings and TGA can lower the rest potential of sulphide minerals. The electrochemical mechanism of TGA depressing is as follows. The dixanthogen adsorbing on the mineral surface will be unstable and reduced when rest potential value of sulphide mineral (E MS ) is below the reversible potential of reduction of dixanthogen to xanthate (E X -/X2 ) in the presence of TGA; flotability of sulphide mineral becomes bad; inversely, the coatings of dixanthogen on mineral surface will keep stable, sulphide mineral keeps good flotability. The electrochemical condition of separation of two sulphide minerals by TGA is E MS1