【作者】 刘志雄；

【导师】 尹周澜；

【作者基本信息】 中南大学 ， 冶金物理化学， 2012， 博士

【摘要】 汤丹低品位氧化铜矿和兰坪低品位氧化锌矿分别为中国大型氧化铜矿和氧化锌矿,难以用传统浮选技术分离与富集,也不宜直接酸浸。本文采用氨-硫酸铵体系,通过研究不同含铜矿物的浸出行为及氧化铜矿-氧化锌混合矿的浸出工艺,期望为湿法炼铜／锌工艺提供基础数据和理论指导。本文系统研究了几种含铜矿物在氨-硫酸铵溶液中非氧化氨浸和氧化氨浸的行为,在此基础上提出低品位氧化铜矿氧化氨浸新工艺和低品位氧化铜矿-氧化锌矿混合矿催化氧化氨浸新工艺。具体内容与结论如下：1.系统研究了孔雀石矿物在氨-硫酸铵溶液中非氧化氨浸过程。通过对比研究孔雀石在氨水溶液和氨-硫酸铵溶液中的浸出行为,发现氨-硫酸铵体系有利于孔雀石的浸出；在氨-硫酸铵溶液中,影响孔雀石浸出速率的主要因素为反应温度、矿物粒度、氨浓度和硫酸铵浓度；在氨-硫酸铵溶液中,孔雀石的浸出动力学行为符合混合控制的收缩核模型,浸出过程受界面传质和残留固体膜层扩散混合控制,反应的表观活化能为26.75kJ/mol,浸出动力学方程为：2.系统研究了斑铜矿在氨-硫酸铵体系中的氧化浸出行为。研究发现温度、反应时间、矿物粒度,过硫酸钠用量以及氨与硫酸铵浓度是影响斑铜矿氧化浸出的主要因素；斑铜矿浸出动力学行为符合混合控制的收缩核模型,浸出过程受界面传质和残留固体膜层扩散混合控制,反应表观活化能为15.63kJ/mol,浸出动力学方程为：根据斑铜矿浸出渣XRD分析结果,提出过硫酸盐氧化浸出斑铜矿反应的可能机理为：3.系统研究了低品位氧化铜矿在氨-硫酸铵溶液中非氧化氨浸过程,确定其浸出动力学行为符合扩散控制的收缩核模型。在氨-硫酸铵溶液中,影响低品位氧化铜浸出速率的主要因素为氨和硫酸铵的浓度、反应温度、液固比和矿物粒度。浸出渣的化学物相分析和SEM-EDS分析结果表明：低品位氧化铜矿中的孔雀石全部浸出、硫化铜矿少量溶解,而硅孔雀石难以浸出,是影响低品位氧化铜矿中铜的浸出的主要原因。低品位氧化铜矿的浸出行为可用扩散控制的收缩核模型来描述,浸出过程受残留固体膜层的扩散所控制,反应的表观活化能为25.54kJ/mol,浸出过程动力学方程为：4.系统研究了低品位氧化铜矿在氨-硫酸铵溶液中的氧化氨浸过程,确定其浸出动力学符合混合控制的收缩核模型,浸出过程受界面传质和残留固体膜层扩散混合控制,反应的表观活化能为22.91kJ/mol,浸出动力学方程为：由此,首次提出低品位氧化铜矿过硫酸盐氧化氨浸新工艺。研究发现,过硫酸铵盐、钠盐和钾盐等作为氧化剂可以氧化低品位氧化铜矿中的硫化矿,其中以过硫酸铵的氧化效果最好,氧化氨浸的铜浸出率比非氧化氨浸的铜浸出率至少高9%。SEM-EDS及物相分析结果表明,斑铜矿可以被过硫酸盐氧化而溶于氨性溶液中。5.以氨-硫酸铵体系中浸出低品位氧化铜矿得到的Cu(NH3)42+为催化剂,催化氧化浸出低品位氧化锌矿,提出了以过硫酸盐为氧化剂,Cu(NH3)42+催化氧化浸出ZnS的反应机理为：首次提出低品位氧化铜矿和氧化锌矿混合矿的催化氧化氨浸新工艺。研究发现,浸出温度,铜矿和锌矿的质量比,液固比,氨、硫酸铵和过硫酸铵的浓度是影响混合矿浸出的主要因素,锌浸出率比铜浸出率低。浸出渣SEM-EDS分析结果表明：在氨性溶液中,低品位氧化锌矿中的硅酸锌发生溶解,溶解析出的二氧化硅吸附在矿物表面从而阻碍锌的进一步浸出,铁酸锌不被浸出。氧化铜矿-氧化锌矿混合矿催化氧化氨浸的优化条件为：搅拌速度500r/min,铜矿与锌矿质量比为4/10,浸出时间6h,温度50。C,液固比3.6/1mL/g,氨浓度2.0mol/L,硫酸铵浓度1.0mol/L和过硫酸铵浓度0.3mol/L,此时铜和锌浸出率分别为92.6%和85.5%,铜浸出率比低品位氧化铜矿氧化氨浸最佳浸出条件下的浸出率高出4.9%。更多还原

【Abstract】 Tangdan low-grade oxidized copper ore and Nanping low-grade oxidized zinc ore are Chinese massive oxidized copper/zinc ores, respectively. Both of the ores are processed and concentrated difficultly by traditional flotation methods, and are not fitted with the acid leaching technique. In view of these defects, ammonia-ammonium sulfate solution was introduced to dissolve the oxidized copper/zinc ores. The leaching kinetics of several copper ores and leaching technology of oxidative ammonia leaching for oxidized copper/zinc ores are investigated in ammonium solution. All the results will provide the theoretical foundation and basic dates for the hydrometallurgy process of copper/zinc ores.The behavior of non-oxidative and oxidative ammonia leaching of several copper ores in ammonia-ammonium sulfate solution was investigated. A new technology of oxidative ammonia leaching for low-grade copper ore with sulphide copper was put forward and another new technology of catalytic-oxidative leaching of low-grade oxidized copper/zinc mixed ores was proposed. The main conclusions were made as follows:1. The dissolution kinetics of malachite was investigated systematically in ammonia-ammonium sulfate solution.Comparison of the leaching behavior of malachite in ammonia solution and ammonia-ammonium sulfate solution was made. The results show that the dissolution of malachite is favored in the ammonia-ammonium solution. The important factors for the leaching process in ammonia-ammonium sulfate solution are reaction temperature, particle size, concentration of ammonia and ammonium sulfate. The dissolution behavior of malachite coincides with the mixed kinetic shrinking core model, which is based on the interface transfer and diffusion across the solid layer. The activation energy is determined to be26.75kJ/mol and the kinetic equation can be expressed as follows:2. The oxidative leaching behavior of bornite was investigated systematically in ammonia-ammonium sulfate solution. The results show that the reaction time, temperature, particle size, concentration of ammonia and ammonium sulfate and the dosage of sodium persulfate are the main factors to the oxidative leaching process. The dissolution kinetics of bornite is controlled by the mixed kinetic shrinking core model which is affected by both the interface transfer and diffusion across the solid layer. The activation energy is calculated to be15.63kJ/mol and the dissolution kinetics of bornite can be written as follows:The dissolution mechanism of bornite in ammonia solution with persulfate is drawn according to the results of XRD analysis of the residue and can be expressed as follows:3. The non-oxidative ammonia leaching of low-grade oxidized copper ore was studied in ammonia-ammonium solution. The main factors for the leaching contain the concentration of ammonia and ammonium sulfate, temperature, the liquid-to-solid ratio and particle size. The results of the chemical phase analysis and SEM-EDS detection show that malachite is mostly dissolved, sulphide copper ore is dissolved partly and chrysocolla is extracted difficultly. The extraction of copper of low-grade copper ore is determined mainly by the dissolution of chrysocolla.The non-oxidative leaching behavior of low-grade oxidized copper ore can be described by diffusion shrinking model, and the leaching process is controlled by diffusion across the solid layer. The leaching kinetics with an activation energy of25.54kJ/mol can be presented as:4. The oxidative ammonia leaching of low-grade oxidized copper ore was investigated in ammonia-ammonium sulfate solution. The leaching process is determined to be controlled by mixed kinetic shrinking core model, which is affected by both interface transfer and diffusion across solid layer. The leaching kinetics with an activation energy of22.91kJ/mol can be expressed as: A new technique of the oxidative ammonia leaching of low-grade oxidized copper ore with sulphide copper is put forward based on the above results. It is found that sulphide copper ore in the low-grade oxidized copper ore can be oxidized by persulfates including sodium, potassium and ammonium persulfates and the oxidation efficiency of ammonium persulfate is the highest. The extraction percentage of copper by oxidative ammonia leaching is at least9%higher than that of copper by non-oxidative ammonia leaching. The results of chemical phase analysis and SEM-EDS detection show that bornite can be oxidized by persulfate and dissolved in ammoniacal solution.5. The catalytic-oxidative leaching of low-grade oxidized zinc ore was investigated by the catalysis of Cu(NH3)42+produced from low-grade oxidized copper ore in ammonia-ammonium sulfate solution. The dissolution mechanism of ZnS in the zinc ore with the oxidization of persulfate by the catalysis of Cu(NH3)42+is proposed as follows:A new technique of catalytic-oxidative ammonia leaching of low-grade oxidized copper/zinc mixed ores is proposed for the first time.Leaching temperature, the mass ratio of copper ore to zinc ore, liquid-to-solid ratio, the concentration of ammonia, ammonium sulfate and ammonium persulfate are the important factors that affect the leaching process of the mixed ore. The extraction percentage of zinc is lower than that of copper. The results of SEM-EDS analysis of the residue of the mixed ore show that Zn2SiO4is dissolved in ammonia solution and the dissolution of Zn2SiO4is further blocked owing to the adsorption of the precipitated SiO2on the surface of ore. ZnFeO2can not be extracted in ammonia solution.The optimal leaching conditions with a maximum extraction percentage of Cu92.6%and Zn87.5%were determined as follows:the mass ratio of copper ore to zinc ore4/10, temperature50℃, reaction time6h, stirring speed500r/min, liquid-to-solid3.6/1mL/g, concentration of ammonia2.0mol/L, concentration of ammonium sulfate1.0mol/L and concentration of ammonium persulfate0.3mol/L.更多还原