【作者】 黎铉海；

【导师】 王淀佐； 邱冠周；

【作者基本信息】 中南大学 ， 矿物加工工程， 2002， 博士

【摘要】 本研究在总结前人对含砷难浸金矿处理和机械活化强化浸出过程等研究工作的基础上，提出了如何用现代分析测试手段更进一步地研究机械活化强化湿法浸出的机理问题。以广西贵港含砷金精矿和载金矿物—黄铁矿和砷黄铁矿为试验物料，分别在常规的搅拌浸出设备、机械活化设备（搅拌磨、滚筒磨和振动磨样机）中进行试验，并结合扫描电镜和X射线衍射精确分析等手段，主要进行了如下几个方面的研究： （1）次氯酸钠一步法浸金的工艺条件研究，找出影响金浸出率的主要因素； （2）考察机械活化方法强化液固浸出过程的热力学和动力学； （3）寻找不同机械活化方式对难处理金矿浸金的影响和强化效果； （4）探讨表面不作喷涂处理能在扫描电镜下测试半导体矿物表面形貌特征的分析方法； （5）通过表面形貌特征来研究机械活化强化浸出过程的机理； （6）采用X射线衍射物相分析、差热分析和比表面分析等多种测试手段，进一步验证机械活化强化浸出过程和机理。 通过上述的研究，根据实验结果和理论分析，得到如下主要结论： （1）在NaOH-NaClO体系中，Au、As、S可以同时一步浸出，且As、S的浸出的热力学趋势较大，而Au主要以H₂AuO₃^-和HAuO₃^2-形式存在，但对应的热力学自发趋势相对较小；浸出过程受化学反应和内扩散的混合控制。 （2）在NaOH—NaClO浸金体系中机械活化有强化矿物浸出的作用。在次氯酸钠和氢氧化钠的初浓度分别为2.3和1.0mol／L、液固比为10的条件下，在滚筒磨中用φ4mm、含Al₂O₃95％的刚玉球作活化介质活化浸出50～60min时，Au浸出率达到峰值，由无活化时的60％增加到85％，提高了40％左右；As和S的浸出率也分别提高了11％和27％。 （3）伴生矿物被激活、次氯酸钠受热分解损失和金精矿中有机碳的存在是NaOH-NaClO浸金体系中Au浸出率随反应时间的变化呈波峰形态的主要原因，提高次氯酸钠初浓度可消除这种影响。 （4）改进扫描电镜的分析方法可直观清楚地观察到矿物在机械活化作用后的表面形貌特征。经X射衍射高纯硅内标精确分析、晶胞常数、晶胞体积、晶面间距和无序度计算、差热、密度和比表面积分析，一致证实了在机械活化后矿物晶体有无定形化物质的存在。在扫描电镜分析中矿物表面出现的絮状物是无定形化物质的形象表现。 （5）在机械活化浸出过程中，矿物获得能量使晶格变形并产生缺陷，表现为在矿物晶体上产生高能量高活性的无定形化物质，使反应物的△fC增加，热力学自发反应的趋势增大;使矿物与浸出剂的反应改变为无定形化物质与浸出剂的反应，由于改变了反应途径，降低了反应过程的活化能，从而使浸出过程得以强化。 （6）机械活化强化浸出过程的效果随活化时间的增加而增加，一般在活化60min后即有明显的活化效果。在实验所用的活化设备中，活化效果的大小顺序是:搅拌磨>滚筒磨>振动磨样机。高密度材质的磨介质其活化效果较好，而磨介质的直径取决于进入反应体系的固体物料的大小。对于反应过程存在可逆过程的气液平衡体系，以选用密封体系的滚筒磨所获得的强化浸出效果较好;当反应过程为不可逆过程时，选用敞开体系的搅拌磨其强化效果更为显著。对次氯酸钠浸金体系，以选用滚筒磨较为合适。 （7）在搅拌磨中用叻4^、含A】20395%的刚玉球作活化介质活化60min时，毒砂的晶胞体积变化、无序度变化和晶面间距的变化分别增大了0.4%、11 .0%和0.1%左右，特征放热峰值温度由未活化时的546.4℃下降到5 14.5℃;黄铁矿对应的变化分别增大了0.2%、8.0%和0.1%左右，特征放热峰值温度由未活化时的414.2℃下降到367.8℃。在相同的活化条件下，毒砂比黄铁矿更易活化。 此外，本研究解决了半导体矿物在扫描电镜下不作表面喷涂处理的测试问题，通过对机械活化强化浸出过程的机理研究，解释了原来需在苛刻条件（高温、高压、高浓度）下才能进行的反应，而在机械活化作用下却可以在较缓和的条件下进行、某些用常规热力学计算认为是不可能进行的反应，在机械活化作用下却能够顺利地自发进行到底、一些在常规条件下进行得较慢的反应而在机械活化作用下能够加速进行的原因。该研究结果可应用到各种浸出过程特别是浸出条件苛刻、浸出速率较慢的浸出反应、矿物加工和材料工程等领域，因而具有较大的实用价值。更多还原

【Abstract】 On the basis of summarization of the research results on the treatments of arsenic refractory gold ores and the leaching process of mechanical activation enhancing leaching, how to further study on the mechanism of mechanical activation enhancing leaching has been put forward by means of using modern analysis and test apparatus. Following several questions have been researched using Guangxi Guiguang arsenic-bearing gold concentrate and gold-carrying minerals-pyrite and arsenopyrite as test materials in the normal stirring leaching equipment and mechanic activation equipment ( stirring mill, rolling mill and vibrating grinder) respectively with the combination of modern analysis and test means, such as scanning electron microscope(SEM), X-ray diffraction (XRD) accurate analysis and so on:(D Researches on the technological conditions of one step leaching gold by sodium hypochlorite for finding the main influencing factors of gold leaching rate;(2) Examining thermodynamics and dynamics of enhancing liquid solid leaching process using mechanical activation ways;(3) Looking for the effects of different mechanical activation ways on the gold leaching from refractory gold ore and the enhancing effects;(4) Exploring the analysis method to test the characteristics of shape and appearance of semiconductor minerals by SEM without coating on the surface;(5) Studying the mechanism of mechanical activation enhancing leaching by the characteristics of shape and appearance;(6) Further verifying the process and the mechanism of mechanical activation enhancing leaching by the use of various test means including XRD, differential thermal analysis(DTA), specific surface analysis and so on.The following main conclusions have .been obtained on the basis of the experimental results and theoretical analysis through above researches:?In the system of NaOH ?NaCIO, Au, As and S can be leached simultaneously by one step, in addition, the leaching thermodynamics trends of As and S are bigger, but Au is mainly existed in the presence of H2AuO3" and HAuO32", the corresponding thermodynamics trend is smaller. The leaching process ismix-controlled model by chemical control and inner diffusion control.(D Mechanical activation can enhance the mineral leaching in the leaching gold system of NaOH桸aClO. The leaching rate of Au is up to peak by using 04mm corundum ball with 95% A12O3 as activation medium for 50~60min in the rolling mill when the initial concentration of sodium hypochlorite and sodium hydroxide are 2.3 mol/L and l.Omol/L respectively and liquid-solid ratio is 10, the leaching rate of Au is increased to 85% from 60% without activation, about 40% Au leaching rate is promoted. The leaching rate of As and S also are enhanced by 11% and 27% respectively.(3) The activation of accrete minerals, the heating decomposition loss of sodium hypochlorite and the presence of organic carbon in gold concentrate are the main reasons for the change of Au leaching rate with the change of reaction time hi wave peak state in the gold leaching system of NaOH-NaClO, it can clear this influence by increasing initial concentration of sodium hypochlorite.(4) The characteristics of shape and appearance of minerals after mechanical activation can be observed clearly and directly with improved SEM analysis way. Through XRD accurate analysis with the internal standard method of high-purified silicon, the calculation of unit cell constant, unit cell volume, interplanar distance and disordered degree, and the analysis of DTA, density and specific surface, the presence of amorphous substance on the mineral crystal after mechanic activation is verified unanimously. Floccule watched on the mineral surface in the analysis of SEM is live embodiment of amorphous substance.(5) In the leaching process of mechanical activation, minerals obtain energy and this energy makes crystal lattice distortion and produce defect, this embodiment is to produce high energy and high activity amorphous substance on the mineral crystal, A7G?of reactants is increased更多还原