【作者】 周国华；

【导师】 何伯泉； 蒋玉仁； 薛玉兰；

【作者基本信息】 中南大学 ， 矿物加工工程， 2002， 博士

【摘要】 为了在不影响锌冶炼主系统生产条件下提高湿法炼锌浸出渣中银的浮选回收率，在进行新型捕收剂研制及组合调整剂研究基础上开发出的新药剂制度使锌浸出渣中银浮选的回收率由50％提高到84％。为进一步认识浮选药剂结构与性能的关系，研究了绝对硬度最小原则浮选判据。通过腐蚀极化图（Evans图）等电化学原理与实验方法等手段，建立硫化矿物浮选体系的Evans图理论，阐明了锌浸渣中银矿物浮选体系的电化学作用机理。主要研究结果如下： 1．提高了锌浸出渣中银浮选的回收率 对含银的锌浸出渣浮选银工艺进行了系统研究。研制出环己酮缩氨基硫脲等几种新型捕收剂，开发出银的特效浮选捕收剂H-4及活化剂NS-6。以H-4为捕收剂、NS-6活化剂为主的用药制度下的闭路实验结果表明，银回收率达84.5％，银精矿品位为0.46％。浮选指标超过合同规定的银回收率为75％的要求。 研究表明，新的用药制度抗矿浆中锌离子影响能力强，银精矿中的锌含量比原厂家使用的用药制度少；而且新的用药制度不改变矿浆pH。因此，它不会改变锌生产系统中的酸碱平衡。另外，从新的用药组成及结构看，新的用药制度不会影响锌的电解生产。因此，新的浮选工艺有工业应用前景。 2．进行了银矿物的浮选研究 天然的Ag₂S、Ag及合成的银浸染闪锌矿、AgCl、Ag₂SO₄、Ag₂O的单矿物浮选实验表明，这些矿物在pH≤5.5（锌浸渣浮选银的pH）都具有很好的可浮性。锌离子对银浸染闪锌矿浮选有活化作用，而对AgCl、Ag_SO₄、Ag₂O浮选起抑制作用。 3．提出绝对硬度最小原则浮选新判据 绝对硬度最小原则浮选新判据研究表明，当捕收剂绝对硬度η_F和矿物中金中南大学博士学位论文属离子的绝对硬度几M之和为最小时，捕收剂优先与该矿物作用，即△n矿几计nM。该判据与溶度积肠判据、基团电负性判据xe、能量判据△肠成正比的对应关系。rtF反映了捕收剂对矿物作用的反应活性及其电化学活性。nF越小，捕收剂越易氧化，对矿物的反应活性高，而且与矿物作用的腐蚀电流越大。该判据可预测硫化矿物新捕收剂的浮选性能。对锌浸渣浮选银的应用研究表明，捕收剂H并可把银矿、方铅矿从闪锌矿中分离出来。4.提出硫化矿物一捕收剂浮选体系的腐蚀极化图（Evans图）理论 硫化矿物一捕收剂浮选体系的Ev田招图可以非常直观地分析硫化矿物表面氧化速度大小或硫化矿物一捕收剂反应速度及反应速度控制因素及控制程度，并可判断添加剂的电化学作用机理。 从电化学角度研究了捕收剂的结构与性能关系。硫化矿（方铅矿、黄铁矿）与捕收剂作用的Evans图研究发现，矿物与捕收剂作用的腐蚀电流强度与捕收剂的结构有关。捕收剂的极性基团的反应活性越大，则捕收剂与矿物作用的电流越强。该电流可作为浮选剂结构活性的电化学参数，值得进一步研究。 银矿物一捕收剂的Evans图研究表明，银矿物一捕收剂作用受氧气阴极还原控制。银矿物一捕收剂作用的腐蚀电流随捕收剂浓度的增加或捕收剂的极性基增强而增大。5.探讨浮选抑制剂及浮选活化剂的电化学作用模型 从电化学观点出发，依据参与了矿物电化学反应的浮选抑制剂对矿物浮选体系腐蚀电化学过程发生的主要影响，认为该抑制剂可分成三类:阳极型抑制剂、阴极型抑制剂、混合型抑制剂（阳极、阴极都抑制）。 通过研究锌离子对自然银一捕收剂作用的影响，发现锌离子起阴极型抑制作用。 依据参与了矿物电化学反应的浮选活化剂对矿物浮选体系腐蚀电化学过程的影响，将该活化剂分成三类:阴极型活化剂、阳极型活化剂、混合型活化剂（阴极、阳极都活化）。 研究表明，银浸染闪锌矿中的银离子对闪锌矿的浮选起混合型活化作用，调中南大学博士学位论文整剂NS一6对银矿物浮选起阳极型活化剂作用。6.阐明了银矿物与捕收剂作用的表面琉水产物及电化学反应机理 热力学计算、半导体能带理论分析、红外光谱实验证明银矿物与捕收剂作用的疏水产物是捕收剂金属盐。伏安法、恒电位、恒电流以及交流阻抗法的研究结果表明，银矿物与捕收剂反应是一个不可逆过程。银矿物表面的疏水膜在银矿物表面吸附牢固，且还原时存在较大的过电位，还原速率低。 辉银矿与捕收剂作用的微分电容与电位关系研究表明:当用乙基黄药作为捕收剂时，最适宜的电位区间为0.2一0.4v;而采用H碑的适宜区间为一0.2一0. 6V。更多还原

【Abstract】 In order to upgrade silver recovery of flotation from zinc leaching residues without affecting zinc metallurgical production of main production system, the new chemicals prescription of flotation based on the study of the new flotation collectors and mixed conditioners increases silver recovery from 50% to 84%. The new criterion of flotation reagents has been studied for better understanding structure-reactivity relation of flotation reagents. The theory of electrochemical Evans diagrams of sulphide mineral flotation system has been set up by means of the electrochemical principles and measurements of corrosion Evans diagrams and the electrochemical mechanism of flotation system of silver minerals has been elucidated. The main points of the paper read as follows:1. Silver recovery of flotation from zinc leaching residues raisedThe flotation technology of recovery silver from zinc leaching residues has been systematically investigated. Several kinds of new flotation collectors have been made and the effective new silver collector H-4 and conditioner NS-6have been developed. The locked cycle tests mainly based on collector H-4 and activator NS-6 demonstrate that silver concentrates grade are 0.45% at 84.5% Ag recovery.The flotation results clearly show that the new chemicals prescription of flotation has strong ability to resist Zn2+ effect and the Zn2+ in the silver concentrates obtained by the new chemicals prescription of flotation is less than the old’s in the existing zinc plan. The new flotation technology don’t change the nature pH of ore slurry and will not destroy the acid-base equilibrium of system of zinc metallurgical production. In addition, the chemicals ingredients of the new chemicals prescription will also not affect the zinc electrodeposition of electrolytic zinc production considering the composition and structure of chemicals. So, the new flotation technology has promising future for the industrial application.2. Flotation research of pure silver mineral studiedFlotation tests with synthetic silver minerals (chemically precipitated silver chloride, silver oxide and silver sulphosalt) and silver-doped sphalerite show that all the silver minerals and compounds can be readily floated with high recovery at pH< 5.5 at which silver recovery from zinc leaching residues by using sulphydrylcollectors. Zinc2+ activates the flotation of silver-doped sphalerite while depresses the flotation of AgCl, Ag2SO4 and Ag2O.3. The new criterion of minimum principle of absolute harness for flotation reagents put forthThe new criterion of minimum principle of absolute hardness for flotation reagents has been studied. The results show that the value between absolute hardness of collector, F, and absolute hardness of metal ion in mineral, m, is smallest, The reaction between collector and mineral first take place, that is min= F+ M By comparing with ksp criterion, radical electronegativity criterion xg and energy criterionEt, can symbolizes the ability of flotation collectors fixed on the surface of minerals and collector’s electrochemical activity. When f is smaller, the collector is not only easily oxidized but also has high reaction activity on minerals. In addition,f is smaller, the corrosion electricity of sulphide mineral-collector is large. The new criterion min of flotation can be used to predict the flotation property of new collectors. The application of new criterion min in silver recovery of flotation from zinc leaching residues shows that collector H-4 can separate silver mineral, lead mineral from sphalerite.4. The theory of Evans diagrams of flotation system of sulphide mineral set upwith Evans diagrams of flotation system of sulphide mineral, not only the oxidizing rate of sulphide mineral, reaction rate of sulphide-collector but also the controlling factors of reaction rate can be explained clearly and directly. The electrochemical mechanism of flotation additives can also be analysed by the theory of the Evans diagrams.The relation of structures and properties of collectors ha更多还原