铜阳极泥加压酸浸预处理工艺及机理研究

【作者】 张博亚；

【导师】 彭金辉； 王吉坤；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2008， 博士

【摘要】 铜阳极泥是粗铜电解过程的副产物,产率约占粗铜量的1%左右。铜阳极泥中富集了由铜冶炼原、辅料带入冶炼过程,且不溶于电解液的各种物质。近年来处理铜阳极泥除回收金、银、铜等外,还综合回收硒、碲、铅、砷、锑、镍、铂族金属等。采用先进的工艺技术和高效装备,简化生产工序,加速过程进行,缩短贵金属的占压周期,提高金属回收率和资源综合利用率等是铜阳极泥处理技术的发展趋势。本文综述了国内外对铜阳极泥处理的研究与发展。根据热力学分析和试验研究,首次提出了一个拥有自主知识产权的铜阳极泥加压酸浸预处理新工艺。新工艺实现了铜阳极泥的清洁浸出,是一种环境友好的浸出方法,是对不同成分铜阳极泥处理技术的一种创新。本论文研究的主要内容如下：1.进行了加压浸出过程热力学方面的研究。铜阳极泥中除了含有金属铜外,还含有一定量的贱金属和稀有金属及贵金属金、银等。铜阳极泥的物相组成比较复杂,各种金属存在的形式多种多样,多以硫化物形式存在。为了研究这些金属及其硫化物在浸出过程中的行为,进行了加压浸出过程中铜的热力学性质的研究,从热力学方面对加压浸出过程中铜脱除的可行性进行了计算和分析；绘制了298K、373K下的S-H20系、Cu-S-O-H系、CuFeS2-H2O系、Ag2S-H20系、PbS-H2O系、ZnS-H2O系的φ-pH图,并在此基础上绘制了本研究中铜阳极泥中主要物质的综合MS-H20系的φ-pH图。这些φ-pH图的绘制为铜阳极泥加压浸出提供了理论依据。2.系统地进行了不同条件下铜阳极泥加压酸浸脱铜的试验研究。进行了铜阳极泥加压酸浸脱铜的实验室小型试验和扩大试验的研究。通过对水洗阳极泥、粒度、搅拌速度及温度等条件的考查,确定铜阳极泥加压酸浸的条件为：直接用生产过程的湿阳极泥进行调浆,在373K-393K以上,搅拌转速为700r/min。通过系统的加压浸出试验,从动力学分析出发,研究了影响铜阳极泥加压浸出的主要影响因素诸如温度、H2SO4浓度、氧压、浸出时间、液固比等,经优化工艺条件,在较低温度373K-393K、较短浸出时间60min-90min、H2SO4浓度100g/L、液固比5：1、压力0.8MPa的条件下,采用工业纯氧、富氧空气或压缩空气作为氧化剂,铜浸出率均高达98%以上,浸出渣中残留的铜小于0.4%,金属走向合理,贵金属金、银等不被浸出,集中在浸出渣中。3.对铜阳极泥加压酸浸进行了机理研究。分析了铜离子的自催化效应,提出利用Cu2+/Cu+之间电子转移的催化作用,大幅提高了多相反应过程的速度,取消以往的铜阳极泥水洗工序；铜阳极泥加压酸浸机理分析表明,硫酸通过阳极泥周围的液膜扩散到阳极泥的表面这一步骤是反应的控制步骤,对于铜、镍等有价金属,其在预处理过程中是液-固相反应,是以硫酸为浸出剂,生成产物可溶于水,可用“未反应核收缩模型”来描述。经假定反应物在反应过程中保持恒定,对推导出的动力学方程1-(1-x)1/3=(bk’CA0)/(αρBr0)t进行了试验验证。试验结果和该模型的动力学方程吻合较好,得出不水洗阳极泥的表观速率常数为水洗阳极泥的两倍,计算得出反应的活化能为7.838kJmol-1。4.研究开发的富Te阳极泥强化浸出工艺,在温度423K、较短浸出时间90min、H2SO4浓度100g/L、液固比5：1、压力0.7MPa的条件下,以氧气为氧化剂,得到Te浸出率达50%,铜浸出率在99%以上,银浸出较少,集中在浸出渣中。5.对镍含量较高的铜阳极泥进行加压酸浸预处理,经优化工艺条件,在433K、反应时间150mmin、H2S04浓度250g/L、压力0.9MPa、液固比6：1的条件下,均可以获得90%以上的镍浸出率,铜浸出率均在99%以上,银基本抑制在浸出渣中,实现了铜阳极泥中主金属镍的有效浸出,达到杂质金属与贵金属的有效分离。试验结果表明,用加压浸出工艺预处理高含镍量铜阳极泥脱除铜、镍等有价金属是可行的,进一步拓宽了铜阳极泥加压酸浸的应用范围。6.进行了铜阳极泥加压酸浸的半工业试验研究。根据实验室试验结果,对试验条件进行了优化,利用阳极泥中金属相和硫化物的还原性,保证了在高铜浸出率条件下有价金属走向更为集中,有利于稀散金属及贵金属的高效回收。在加压釜工作压力0.8MPa、温度393K-403K、H2SO4浓度100-150g/L、液固比5：1、釜内停留时间100min-120min条件下,采用压缩空气或工业纯氧进行连续加压浸出,均能实现铜浸出率在98%以上、渣含铜在0.5%以下。试验中采用能更好地促进气相在液相中分数的大流量气体氧化剂,大幅度降低了工艺能耗和成本,并大幅提高了生产过程及设备的安全性。在预定工艺控制条件下渣含Cu基本稳定在0.5%左右,最低达0.31%,Te、Ag等均更好地集中于固相中,并有所富集；在连续17天的试验过程中,作业过程运行稳定,加压釜运转率为96.8%,流程通畅,投料率为89.2%。工艺参数易于控制,参数调整过程转换平稳；半工业试验系统的阳极泥处理能力2.5-3.0t/d,平均为2.76t/d。所获工艺技术指标已作为云南铜业股份公司年处理铜阳极泥8000吨加压酸浸预处理工艺产业化系统建设的技术依据。总之,本文研发了一种采用加压酸浸预处理铜阳极泥的新工艺。该工艺不仅铜镍等金属浸出率高、操作简单、流程短；且利用了铜离子生成变价金属的自催化效应,强化反应的进行,反应时间短；整个过程为封闭运行,无废液废气排放,环境可接受性高,符合绿色清洁生产要求,是一种具有很好发展前途的环境友好的处理铜阳极泥的湿法冶金新技术,该技术的推广应用,将会带来巨大的经济效益和社会效益。论文的创新点：1.本文提出在加压酸浸的条件下进行铜阳极泥的预处理新工艺,并获得国家知识产权局发明专利授权(授权号：309983)。试验研究表明,在选定的工艺条件下,铜阳极泥中的铜、镍等有价金属浸出率高、浸出时间短,金属走向合理,贵金属基本富集在浸出渣中,实现了贱金属与贵金属的有效分离；2.本文提出对铜阳极泥进行连续加压浸出预处理,采用能更好地促进气相在液相中分数的大流量气体氧化剂,能耗小,热效高,设备寿命长,过程为自动控制,操作简单,劳动强度小：3.本文提出利用Cu2+/Cu+之间电子转移的催化作用,大幅提高了多相反应过程的速度,取消以往的铜阳极泥水洗工序；4.本文研究了铜阳极泥加压浸出预处理的热力学过程,绘制了298K和373K下的S-H20系、Cu-S-O-H系、CuFeS2-H2O系、Ag2S-H20系、PbS-H2O系、ZnS-H2O系的φ-pH图,确定各金属在加压酸浸条件下的行为及走向,这些体系的热力学研究丰富了铜阳极泥加压酸浸的理论基础。5.本文提出利用铜阳极泥中金属相和硫化物的还原性,保证了在高铜浸出率条件下有价金属走向更为集中,有利于稀散金属及贵金属的高效回收；更多还原

【Abstract】 Copper anode slime is the byproduct in the process of electrorefining, which yield is 1 percent of the blister. There are several kinds of materials concentrated in copper anode slime, which from the raw and auxiliary materials, insoluble in electrolyte. These years, copper, silver and gold are recovered from copper anode slime, selenium, tellurium, lead, arsenic, antimony, nickel and platinum metals are also recovered from it. The develop tendency of the treating technology of copper anode slime are, utilization the advanced technology and high efficiency equipment, simple operation, rapidly process, shorten the holding time of precious metals, enhance the recovery rate of metals and comprehensive utilization of resources.The researches on and advances in the treatment of copper anode slime at home and abroad are. reviewed. Based on the theoretical analysis and explorative experiments, a novel process of copper anode slime pretreated by pressure acid leach is put forward. This process is in possession of independent knowledge property right. The novel process realizes green leaching copper anode slime. It is also an environmentally friendly improvement to the hydrometallurgical methods of treating copper anode slime. At the same time, this process was also an innovation in processing various components of copper anode slime. The main work and conclusions are as follows.1. Thermodynamics researches with the process of pressure leach had been examined. Besides of copper in copper anode slime, it still has a few base metals and precious metals, such as silver and gold, etc. In order to investigate the behaviors of these metals in leaching process, theφ-pH diagrams of systems S-H2O, Cu-S-O-H, CuFeS2-H2O, Ag2S-H2O, PbS-H2O, ZnS-H2O of 298K,373K had been drawn. To analysis the practicability of removing copper from copper anode slime with pressure leach method in thermodynamic aspect, copper thermodynamics had been examined.2. Systematic experimental study and mechanism analysis of removing copper from copper anode slime with pressure leach method under different conditions. The laboratory test of treating copper anode slime with pressure leach method is carried out. It defined the pressure leach conditions through the examined of scrubbing, gradation, stirring rate and temperature. The conditions are, surge with the raw copper anode slime of the productive process, higher temperature, stirring rate of 700r/min. Through analysis of kinetics, the primary factors of affecting pressure leach such as temperature, acidity, oxidation pressure, leaching time, liquid to solid ratio, etc. had been examined. The conditions are,373K-393K, 60-90min, acidity is100g/L, liquid to solid ratio is 5:1, pressure is 0.8MPa. The results show that, the method can realize the aims to remove copper from copper anode slime efficiently whenever use oxygen, oxygenized air or compressed air as gaseous oxidizer. The removal efficiency of copper with such method can be above 98 percent, the copper content of leaching residue is below 0.4 percent.3. The mechanism of pressure leach had been examined. The catalytic action of Cu2+change to Cu+is put forward, which can enhance reaction rate and cancel the scrubbing process. The mechanism analysis of pressure leach shows, the step of sulphuric diffused to the surface of the copper anode slime through the fluidized membrane is the control step of the reaction. The valuable metal as copper and nickel are liquid-solid reaction in the pretreated process, the product is water-soluble, can be described by shirking dense-core model. Assume the reactor keep constant in the react course, the kinetic equation is tested by the experiment. The results shows, the apparent rate constant of scrubbing is double of no-scrubbing, the activation energy is 7.838kJmol-1, which shows the diffusion resistance determine the leach rate of anode slime.4. The examined technology of remove tellurium from copper anode slime is improvement and innovation of the pressure leach method, with the conditions are,423K,90min, acidity is100g/L, liquid to solid ratio is 5:1, pressure is 0.7MPa, oxygen as the oxidizer, the leaching rate of tellurium is above 50 percent, copper leaching rate is above 99%, silver leaching rate is lower, which enriched in leaching slag.5. The experiment of removing nickel from copper anode slime with pressure leach method is carried out. With the conditions are,433K,150min, acidity is250g/L, liquid to solid ratio is 6:1, pressure is 0.9MPa, oxygen as the oxidizer, the leaching rate of nickel is above 90 percent, the leaching rate of copper is above 99 percent, silver concentrated in slag. It can attain the aims to remove nickel from copper anode slime with pressure leach method, which opens up wide prospect for the application of the novel process.6. The pilot trail of copper anode slime treated by pressure leach method is carried out. Based on the results of the bench-scale experiment, the reducibility of metal phase and sulphide of copper anode slime is put forward, which can centralize the flow of valuable metal with the condition of higher copper leaching rate and be propitious to recover rare scattering and precious metals efficiently. It can attain the aims to remove copper from copper anode slime whenever use oxygen, oxygenized air or compressed air as gaseous oxidizer. The conditions as follows, the working pressure at 0.8MPa,393K-403K, 100-150g/L H2SO4,100-120min, the removal efficiency of copper is above 98 percent, the content of copper in leaching residue is below 0.5 percent. Utilization of oxidizer with big flow rate is put forward, which can promote the gas distribute into liquid quickly, cut down the cost and consumption of the technology, enhance the security of the process and equipment. It can attain the better indices of 0.5 percent of copper in leaching residue, silver and gold are concentrated in leaching residue. During the course of the experiment for 17days, the process is running stable, the running ratio of autoclave is 96.8 percent, the material input ratio is 89.2 percent. The technology parameter can be controlled easily, it also stable for changing parameters. The pilot trail capacity of treating copper anode slime is 2.5-3 tons per day, the average value is 2.76 tons per day. The technology indices from the experiment can be as the industrial construct technical reference of 8000 tons-per year of Yunnan copper corporation Ltd.In summary, a novel process of pressure acid leaching of copper anode slime is researched. The advantages of this process are, high leaching efficiency of copper and nickel, simple operation, short flow sheet, utilize self catalytic action of copper ion change to another valence state, which can strengthen process of the reaction, shorten reaction time. The whole process is working in blocking condition with high environmental acceptability. This process meets the environments of green clean production, and is a new promising hydrometallurgical method of copper anode slime.The following contributions have been made:1. A novel process of copper anode slime pretreated by pressure acid leach is put forward for the first time, which is authorized by State Intellectual Property Office of the P.R.C. Certificate No is ZL 200510011022.9,309983. The experiment result shows, on the conditions of the experiment, the leaching rate of copper and nickel are higher, leaching time is shorter, the metals are distributed reasonable, precious metals concentrated in leaching slag. It realized that base metals separated with precious metals efficiently.2. The continuous leaching method with copper anode slime has been presented. Utilization of oxidizer with big flow rate can promote the gas distribute into liquid quickly. The whole procedure is control by the computer with simple operation, thermal efficiency, equipment with long lifetime.3. The catalytic action of Cu+change to Cu+is put forward, which can enhance reaction rate and cancel the scrubbing process.4. The thermodynamic process of the copper anode slime with pressure leach method had been examined. Theφ-pH diagrams of systems S-H2O, Cu-S-O-H, CuFeS2-H2O, Ag2S-H2O, PbS-H2O, ZnS-H2O of 298K,373K had been drawn. It can be defined the behaviors and the flow of the metals in pressure leach conditions. The researches enriched the theoretical basis of pressure leach method of copper anode slime.5. The reducibility of metal phase and sulphide of copper anode slime is put forward for the first time, which can centralize the flow of valuable metal with the condition of higher copper leaching rate and be propitious to recover rare scattering and precious metals efficiently.更多还原