Selective depression mechanism of combination of lime and sodium humate on arsenopyrite in flotation separation of Zn-As bulk concentrate

组合抑制剂石灰和腐植酸钠在锌砷混合精矿浮选分离中对毒砂的选择性抑制机理

Lime(CaO)and sodium humate(NaHA)were used as the combined depressant for arsenopyrite pre-treated by CuSO_(4) and butyl xanthate.Micro-flotation tests show that the combined depressant CaO and NaHA achieved the selective depression of arsenopyrite.Closed-circuit lab-scale test results indicate that the synergistic effect of CaO+NaHA achieved a satisfactory flotation separation of sphalerite and arsenopyrite,for which the Zn grade and recovery of Zn concentrate were 51.21%and 92.21%,respectively.Contact angle measurements,adsorption amount measurements and X-ray photoelectron spectroscopy analysis indicate that the dissolved calcium species(mainly as Ca(2+))were adsorbed on the mineral surfaces,thereby promoting NaHA adsorption.Moreover,the surface of the arsenopyrite absorbed more amount of calcium species and NaHA than that of the sphalerite,thereby accounting for the strong hydrophilic surface of arsenopyrite.The adsorption of NaHA on arsenopyrite was mainly chemical adsorption through its carboxyl groups and Ca atoms,whereas that on sphalerite surface was relatively weak.

采用石灰和腐植酸钠作为经硫酸铜活化和丁黄药捕收后毒砂的组合抑制剂。纯矿物浮选试验表明,组合抑制剂石灰和腐植酸钠能选择性地抑制毒砂。实验室小型闭路试验结果表明,石灰和腐植酸钠的协同抑制作用能较好地实现闪锌矿和毒砂的浮选分离,得到锌精矿中锌品位为51.21%、锌回收率为92.21%的良好指标。通过接触角测试、吸附量测试和X射线光电子能谱研究组合抑制剂的抑制机理。机理研究表明,溶解钙组分(主要为钙离子)吸附于矿物表面,促进腐植酸钠的吸附;毒砂表面比闪锌矿表面吸附更多的钙组分和腐植酸钠,使毒砂表面具有强亲水性。腐植酸钠在毒砂表面的化学吸附主要是通过其分子结构中的羧基与毒砂表面的钙原子发生作用,而其在闪锌矿表面的吸附较弱。