低品位氧化锌矿元素硫水热硫化应用基础研究

【作者】 李存兄；

【导师】 魏昶；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2012， 博士

【摘要】 金属锌被称为“现代工业的保护剂”,是国民经济健康发展不可缺少的战略金属,也是目前用量最大的有色金属冶金产品之一。随着硫化锌资源的日益枯竭,氧化锌资源的开发利用已引起人们重视。低品位氧化锌矿水热硫化转化预处理-浮选新工艺能显著改善氧化锌矿常规浮选工艺存在的不足之处,本论文在前期系统工艺研究基础上,开展了低品位氧化锌矿水热硫化转化基础理论研究,主要成果如下：(1)采用多种检测手段对云南兰坪地区的碳酸盐类低品位氧化锌矿和硅酸盐类低品位氧化锌矿进行矿物学分析。矿石中主要的锌矿物为菱锌矿、闪锌矿,脉石矿物主要为石英、方解石等；菱锌矿、闪锌矿与脉石矿物之间紧密连生、交代或穿切形成错综复杂的镶嵌关系。硅酸盐类低品位氧化锌矿中异极矿及硅锌矿矿物部分以不规则状、粒状嵌布于脉石矿物,部分与菱锌矿以集合体的形式嵌布于脉石矿物,使得有价金属与脉石矿物难以分离。(2)对低品位氧化锌矿元素硫水热硫化高温热力学过程进行了分析。绘制了工艺条件温度下S-H2O系E-pH图,随着体系温度的升高,S2-的优势区面积增大,S2-、H2S、HS-离子的稳定区域向低pH的方向移动；氧化锌矿中锌的主要单矿物水热硫化反应高温热力学分析结果表明,菱锌矿、异极矿、硅锌矿和红锌矿在高温水热体系下的水热硫化反应都易于发生(3)分别研究了合成异极矿和纯菱锌矿的元素硫水热硫化转化过程动力学机理。异极矿元素硫水热硫化转化反应初期受化学反应控制,反应表观活化能分别为50.23kJ/mol;而后期逐步转变为受固体产物层的扩散控制,反应表观活化能为11.12kJ/mol。纯菱锌矿元素硫水热硫化转化过程受穿过固体产物层的扩散控制,其表观活化能为14.67kJ/mol。在200℃下硫化120min后菱锌矿的水热硫化过程已基本完成。(4)开展了碳酸盐类低品位氧化锌矿水热硫化预处理-浮选实验研究。在水热硫化优化技术参数矿浆起始pH=9、颗粒粒度57-74μm、硫磺摩尔倍数2.0、转化温度180℃、硫化时间240min、搅拌转速500rpm的条件下,锌和铅的硫化转化率分别达73%和86%以上,硫化产物中分别有61%的锌和94%的铅以硫化物形式存在。采用铅锌混合浮选工艺流程获得的合精矿中铅品位19.59%,锌品位35.76%,铅锌回收率分别达69%和81%,铅锌回收率大幅度提高。(5)开展了硅酸盐类低品位氧化锌矿水热硫化预处理-浮选实验研究。在水热硫化优化技术参数矿浆起始pH=9、颗粒粒度57-74μm、硫磺摩尔倍数2.5、转化温度180℃、硫化时间240min、搅拌转速600rpm的条件下,锌和铅的硫化转化率分别达55%和83%以上,大部分异极矿发生矿相重构生成硫化锌,而脉石矿物如石英、方解石等则不发生变化,从而改变了有用矿物与脉石矿物因表面性质相似而无法高效分离的局面,为后续的浮选富集创造了有利条件。采用铅锌混合浮选工艺流程获得的混合精矿中铅品位15.84%,锌品位34.53%,铅锌回收率分别达73%和83%。更多还原

【Abstract】 Zinc, which is known as the modern industrial protective agent, is an indispensable strategic metal to the healthy development of national economy and is one of the current largest amounts of non-ferrous metallurgical products. The development and utilization of zinc oxide resource has paid much attention with the dipletion of zinc sulfide ores. The new flowsheet on pretreatment of low grade zinc oxide ore by hydrothermal sulphidation and further flotation of the suphidised products will obtain a better parameter. At the basis of our previous technology study, the present paper mainly focused on the theory foundation of hydrothermal sulphidation of low grade zinc oxide ore. Listed below are the main results:(1) The carbonate-hosted zinc oxide ore and silicate-hosted zinc oxide ore form Lanping of Yunnan was analyzed by modern analysis methods. The main zinc ore minerals are smithsonite and sphalerite, and gangue minerals include quartz, calcite. etc. Smithsonite, sphalerite and gangue minerals usually exist in complex relationships. Hemimorphite and zinc silicate in silicate-hosted zinc oxide ore are irregular embeding of hemimorphiteq with quarz will cause it more difficult to enrich by flotation.(2)Hydrothermal sulphidation of low grade zinc oxide ore with elemental sulfur was thermodynamically analysed. The potential-pH diagrams for sulfur water were plotted at experimental temperautre. The stablity regions S2-、H2S、and HS-moved to lower pH values with rising temperature. According to the thermodynamic analysis results smithsonite, hemimorphite, zinc silicate and zinc oxide can easily be conversed to zinc sulphide at experimental temperature.(3) The kinetics of hydrothermal sulphidation of hemimorphite and smithsonite with elemental sufur were studied respectively. Sulphidation of hemimorphite was controlled by the chemical reaction during the early stage of reaction with activation energy of50.23kJ/mol, and then was controlled by solid product layer diffusion with activation energy of11.12kJ/mol. Sulphidation product was detected by XRD and the result shows that it would be helpful for conversion of hemimorphite to zinc sulfide with an increase of temperature. Sulphidation of smithsonite was controlled by solid product layer diffusion with activation energy of14.67kJ/mol. hydrothermal sulphidation of smithsonite almost completed at200℃for120min.(4) Experiments of hydrothermal sulphidation of carbonate-hosted zinc oxide ore by technology of presulphidation-flotation were carried out. Sulphidation rate of zinc and lead were over73%and86%nder the optimized technical parameters of pulp initial pH=9, particle size57-74μm, sulfur mole raito2.0, temperature180℃.240min and stirring speed of500rpm. Sulphidation products were dressed by mixed flotation flowsheet, which gave much higher recoveries of69%lead and81%zinc. A flotation concentrate was obtained with35%Zn and19%Pb from the material which was treated by sulfidation.(5) Experiments of hydrothermal sulphidation of silicate-hosted zinc oxide ore by technologies of presulphidation-flotation were carried out. Sulphidation rate of zinc and lead were over55%and83%under the optimized technical parameters of pulp initial pH=9, particle size57-74μm, sulfur mole raito2.5, temperature180℃,240min and stirring speed of600rpm. During the sulphidation procees most of the hemimorphite was conversed to zinc sulfide, while gangue minerals such as quartz and calcite were still in their original forms, and the diffferent surface property between useful minerals and gangues would be advantage for further flotation. Sulphidation products were dressed by mixed flotation flowsheet, which gave much higher recoveries of73%lead and83%zinc. A flotation concentrate was obtained with34%Zn and15%Pb from the material which was treated by sulfidation.更多还原