【作者】 刘辉；

【导师】 覃文庆； 孙伟；

【作者基本信息】 中南大学 ， 矿物加工工程， 2005， 硕士

【摘要】 铅生产工业中,从铅矿物原料生产铅金属,进而深加工制备含铅材料的过程涉及多步高温、高能耗工序,尤其铅火法炼铅过程,SO₂、铅尘等的产生对环境污染大。因此,进一步开展铅提取和材料制备技术的基础研究是发展经济和社会可持续发展的迫切要求。 目前,我国铅蓄电池耗铅量占到总耗铅量的70%,氧化铅粉体是铅酸蓄电池中常用的活性物质。为此,本论文以方铅矿精矿为原料,采用“浸出-选择性除杂-化学合成”三步法,系统研究了制备超细PbO粉体的新工艺流程。分析了不同体系下方铅矿精矿浸出过程,通过腐蚀电化学测试和溶液化学计算探讨了浸出过程有关机理,考察了从浸出产物氯化铅合成超细β-PbO粉体过程中各个因素对硫酸铅和前驱体粒度的影响及前驱体热分解反应的具体历程。 研究结果表明,碳铵体系下方铅矿精矿浸出率偏低,最高不超过60%。腐蚀电化学测试,强化浸出实验结合X射线衍射分析表明浸出过程中PbCO₃固体钝化膜的形成是影响浸出率不高的主要原因。三氯化铁体系下浸出方铅矿精矿,浸出速度快,浸出率高,最高可达97.39%。浸出液“冷却—结晶—过滤”过程具有良好的除杂功效。溶液化学计算结果表明该浸出过程中PbCl₂主要以[PbCl₄]^2-络合物的形式存在于溶液中,[Cl^-]_T=0.918mol/L时PbCl₂能较好的呈固态析出,[Cl^-]_T>0.918mol/L,PbCl₂固体因氯络合作用而溶解,随体系温度升高,[Pb²⁺]_Tmi点下降,是冷却结晶析出PbCl₂晶体的化学原理。腐蚀电化学分析结果进一步验证了饱和氯化钠介质中氯络合作用的发生。从浸出产物氯化铅合成超细β-PbO粉体过程中各个因素对硫酸铅和前驱体粒度均有不同程度的影响。前驱体物质（碳酸铅和碱式碳酸铅的混合物）在不同温度下热分解反应可分别得到稳定的中间产物PbO_x、Pb₃O₄和β-PbO。制得的β-PbO粉体为黄色斜方晶系,且不含其它杂质峰,粉末颗粒呈片状,平均粒径为4.102μm,为超细粉体,纯度高。 另外,二次铅资源的生产是铅生产工业的另一重要组成部分,国内尚处于初步发展阶段,探索新的再生铅生产工艺具有重要的理论意义和现实意义。本论文以废旧铅蓄电池铅膏为原料,通过“铅膏碳酸化转化-溶解-化学合成”的方法初步探讨了从铅膏直接制备超细更多还原

【Abstract】 In the modern lead industry, the production of lead involves fire metallurgy to produce crude lead from lead concentrates and electrolysis of the crude lead to produce electrolytic lead, then deep processing to prepare lead materials. Owing to the emission of SO₂ and lead vapour as well as lead filled dust during processes of lead metallurgy and electrolysis, so there is serious pollution to environment. Under the current pressures of strict environmental regulations, it is necessary to seek other methods to produce lead materials. In this paper, a new approach to direct produce lead monoxide from galena concentrates has been proposed.PbO powders as an active material of lead acid batteries are prepared from galena concentrates through three-step, including leaching, selective purification and chemical synthesized. This process without pollution not only simplifies the traditional process of the production of PbO, but enhances the efficiency of processing lead mineral resources.In this thesis, two sorts of leaching systems both ammonium carbonate system and ferric chloride system were investigated respectively. The results of leaching experiments in ammonium carbonate system indicate that leaching rate is not more than 60%. The reason for lower leaching rate is the formation of passivation film which is composed of PbCO₃ crystal from X-ray diffraction analysis. Comparatively, in ferric chloride system leaching rate can reach 97.39% just for 40 minutes. It is further found that the process of cooling, crystallization and filtration has the function of purification. By means of solution chemistry calculation, it demonstrates that [PbCl₄]^2- is the dominant species for the reaction product of PbCl₂, which begins to dissolve around pCl_op 0.04 （[Cl^-]_T=0.918mol/L）. The results of corrosion electrochemistry present that corrosion current increases with the increase of ferric chloride concentration, but passivation phenomenon would be appeared while the ferric concentration is above of 6×10^-4 mol/L. And corrosion current in sodium chloride solution is higher than without it, which shows that chloride ions greatly contribute to the improvement of leaching rate duoto complexation of chloride. /? -PbO prepared in this thesis is rhombic. There is no other product from X-ray diffraction analysis with the average particle size of /?-PbO of 4.102um, and it is flaky powder from scanning electron microscope spectrum. Intermediate samples, including PbOx, PbsO4 and p -PbO, can exist stably in the process of calcining the precursor at different temperature.On the other hand, the production of secondary lead resources is also important to all of lead industry, which is in the initial stage of development in China. In this thesis, three-step process for ultrafine powder of PbSO4, including carbonation transformation of lead pastes in sodium carbonate solution, chemical dissolving and method of chemical sedimentation, has been presented. Orthogonal designing was applied to study the correlation of factors connected with conversion rate. The results shows that their influencing order is: Na2CO3 concentration > reaction temperature > reaction time > stirring speed, and the optimum conversion condition is also obtained. The characters of calcining reaction for lead pastes transformed by carbonation were studied by TG-DTA. The results expressed that lead sulfate in lead pastes can be transferred into lead carbon, completely, which makes the calcining temperature of lead pastes decrease from 880.56°C to 357.86°C and avoid emission of SO2 during disposing waste lead storage batteries by fire metallurgy, as well as diminish energy use. With the lead pastes after transformation dissolved by fluosilicate acid, and then synthesized by the method of chemical sedimentation, orthorhombic lead sulfate would be prepared. There is no other product from X-ray diffraction analysis and its average particle size is about 3.224um.更多还原