高硅氧化铅锌矿加压酸浸工艺及理论研究

【作者】 贺山明；

【导师】 王吉坤；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2012， 博士

【摘要】 氧化锌矿是硫化锌矿床长期风化的产物,也可作为炼锌的一种原料。我国是氧化锌矿资源较为丰富的国家之一,开发应用此类矿石有很好的经济价值。由于所含矿物的特性,氧化锌矿的浮选回收迄今为止还是个难题；若采用火法处理,为了满足其渣型,需配入大量的熔剂及消耗大量燃料,能耗、成本高且污染环境；常压酸浸处理异极矿和硅酸锌矿的最大难点是酸浸过程生成难以过滤的硅胶；碱法浸出和氨法浸出对湿法炼锌工艺和设备提出了新要求,仅停留在实验室研究或半工业阶段。本论文研究了以空气为加压气体,对高硅氧化铅锌矿采用加压酸浸处理新工艺,并对其中的关键技术进行了理论和试验研究。概括为以下主要内容和结论：1、计算了主要酸溶反应的△Gθ与T关系方程,以及K值与T的关系式；并得出结论：当反应温度为50℃左右时,高硅氧化铅锌矿中含锌物质及其他矿物与硫酸的化学反应基本上都能自动向右进行；对于硅酸脱硅的反应,常温常压下,该反应很难向右进行,但当温度≥120℃时,反应可以自动向右进行。2、计算并绘制了不同温度下的Zn-H20系和Zn-Si-H2O系的ET-pH图。分析得出：在高温条件下,为了浸出锌,需控制相对较高的始酸浓度；为了确保控制在SiO2物相稳定区,需维持相对较高温度(≥120℃)条件。3、高硅氧化铅锌矿常压酸浸存在以下问题：浸出矿浆不好过滤；工艺条件要求严格控制；锌回收率不高,均小于92%；矿浆中的锌与硅、铁等杂质不能有效分离,后续还需进行脱硅及除铁工序处理；耗酸大；常压浸出液和浸出矿浆很容易转化成硅冻胶,从而无法液固分离。4、系统研究了加压浸出工艺条件对浸出效果和矿浆过滤性能的影响,得出了最佳工艺条件为：液固比3：1-4：1,始酸浓度120～140g/L,釜内压力0.4～0.6MPa,温度110～130℃,粒度-0.074mm占95%以上,时间60min,搅拌转速400～500r/min。在此条件下,Zn浸出率>97%,Si浸出率<1%,Fe浸出率<6%,铅入渣率>97%,产液速率>1030L·m-2·h-1,浸出液含Zn2+118～131g/L、Fe0.0087～0.026g/L、Si0.04～0.16g/L。与常压酸浸比较,加压酸浸工艺具有矿浆过滤性能良好、锌直接回收率高、反应速度快、工艺流程简洁、脱硅效果好、高效除铁、耗酸低、原料适应性强等优势。5、对于溶液脱硅的研究表明：为了避免硅胶的产生,可控制较高的反应温度以利于高温脱硅；或选择较低的始酸浓度、矿浆终点pH值在3～5.5范围,利用pH值、电解质等影响促使硅溶胶聚集沉淀。过滤性能良好的浸出渣在XRD图上显示出衍射线的强度与清晰度都较为显著,而过滤性差的浸出渣表现出X射线衍射强度较弱且模糊。SEM分析表明：难过滤的浸出渣中含有树枝状的硅胶,硅胶之间塞满了其它微小颗粒,没有太多缝隙空间利于液体的流通。6、人工合成硅酸锌加压酸浸过程的研究结果表明：升高温度能破坏硅溶胶的稳定性进而有利于硅酸的脱水过程；产液速率随终点pH值的升高而增大；浸出体系的水量超过了某个限度时,硅浸出率的升高幅度显著,促进了硅胶的生成；控制恰当的工艺条件,则荷负电的硅胶与荷正电的氢氧化铁溶胶在静电引力作用下会完全聚沉。7、系统研究了加压酸浸动力学,计算出了反应的表观活化能为14.3kJ/moL、始酸浓度和釜内压力影响的表观反应级数分别为1.139和0.277,酸浸过程受内扩散控制；建立了四个工艺条件共同对锌浸出影响的宏观动力学方程：1-2/3R-(1-R)2/32.9546×10-11×r0-2CH2SO41.139×PAir0.277×exp(-14330/RT)t8、跟踪考察了高硅氧化锌矿加压酸浸工艺工业化生产情况,优化了工艺技术条件,考察了连续化生产情况。结果表明该工艺具有锌回收率高,浸出料浆过滤性能好,工艺流程简短,反应条件易于实现和控制,浸出液含硅、含铁低无需额外除杂处理,生产成本低等优点。更多还原

【Abstract】 Zinc oxide ore is the product of long-term weathering of sulfide lead-zinc deposits, it also can be used as a raw material for zinc. China is one of the countries which zinc oxide ore resources are more abundant, development and application of such ores have great economic value. As contained in the special properties of mineral, its flotation recovery is still a problem so far; If use of fire treatment, need with a lot of flux into and consume large amounts of fuel in order to meet its residue type, so high energy consumption high cost and no environmental; The greatest difficulty of sulfuric acid leaching of hemimorphite and zinc silicate ore in atmospheric pressure is leaching process generates silica gel is very difficult to filter; Alkaline leaching and ammonia leaching are put new demands on zinc hydrometallurgy technology and equipment, so only to remain in the laboratory or semi-industrial stage.This paper studied a new process of with air as the pressurized gas, pressure leaching of high silica lead-zinc oxide ore in sulfuric acid medium, theoretical and experimental research about the key technologies of the new process. The main elements and conclusions were summarized as follows.1、The relationship equation between standard Gibbs free energy ΔGθ and temperature T about the main sulfuric acid dissolved reaction and the relationship equation of the equilibrium constant K and the temperature T have been calculated. The following conclusions was obtained as follows:When the reaction temperature is50℃or so, the chemical reaction of lead-zinc oxide ore containing material with sulfuric acid can basically automatic right to; For the desilication reaction of silicic acid, the reaction is difficult to place at normal temperature in atmospheric condition, but when the temperature was higher than120℃, the reaction can be carried out automatically to the right.2、The ET-pH diagram of the Zn-H2O system and the Zn-Si-H2O system at different temperatures were calculated and plotted. The following conclusions was obtained as follows:in order to leach zinc compounds, the need to control the relatively high concentration of sulfuric acid when the high temperature condition; in order to ensure control in SiO2phase stable region, the need to maintain a relatively high temperature (≥120℃).3、The main problem about atmospheric acid leaching of high silica lead-zinc oxide ore in sulfuric acid medium are as follows:leach pulp is not easy to filter; requires strict control of process conditions; zinc recovery rate is not high, less than92%; zinc and silicon、iron or other impurities can not be effectively separated, so need to add the follow-up of silicon and iron removal treatment processes; large consumption of acid. Atmospheric leaching fluid and leaching pulp were easily converted into silica gel which can not be separated.4、The pressure leaching process conditions on the main component of lead-zinc oxide leaching effects and pulp filtration performance was systematic studied. The optimum condition was obtained as follows:liquid-solid ratio is3:1～4:1, sulfuric acid concentration120～140g/L, with air as the pressurized gas and pressure0.4-0.6MPa, leaching temperature110～130℃, ore particle size-0.074mm>95%, leaching time60min and stirring speed400～500r/min.Under this process conditions, Zn leaching rate>97%, Si leaching rate<1%, Fe leaching rate<6%, the rate of lead into slag>97%, the fluid production rate>1030L·m-2·h-1, leaching solution containing Zn2+118～131g/L, Fe0.0087～0.026g/L, Si0.04-0.16g/L. Compared with the acid leaching at atmospheric, pressure acid leaching process has the following advantages:good pulp filtration, high recoveries rate of zinc, fast speed of response, the process is simple, effective removal of silicon and iron, low acid consumption, strong adaptability of raw materials, etc.5、From solution desilicating study showed that:in order to avoid the production of silicone and ensure a better filter performance, need to controlling higher reaction temperature to facilitate the removal of silicon or lower acid concentration and the end pH range of slurry is3～5.5which can use of pH、electrolytes and other influence to bring together precipitated silica. The good filtration leaching residue in the XRD map showing the intensity and clarity of crystalline diffraction lines are more significant; But the poor filter residue showed X-ray diffraction intensity is weak and vague. SEM analysis showed that:the poor filter residue containing dendritic silica gel and filled with other small particles among them, so there is no much more space conducive to the flow of liquid.6、The pressure acid leaching of synthetic silicate zinc was studied. The results showed that elevated temperatures can damage the stability of silica gel and thus conducive to the dehydration process of silicate; The rate of fluid production increased with the end pH increases; When the amount of water volume in leaching system is greater than a certain limit, the leaching rate of silica increased significantly and promote the formation of silica gel; The negatively charged silica and positively charged ferric hydroxide sol in the role of electrostatic forces will be completely coagulation when the right condition was control.7、The kinetics of pressure sulfuric acid leaching of high silica lead-zinc oxide ore was systematic studied. The apparent activation energy of the reaction is14.3kJ/moL and the apparent reaction order of sulfuric acid and pressure affect is1.139and0.277respectively; Acid leaching process is affected by the proliferation of control. The macro-kinetic equation of four process conditions common affect the leaching of zinc was created as follows:8、The technology of pressure sulfuric acid leaching of high silica zinc oxide ore has been tracking inspection. Technical process conditions have been optimized and continuous production was also examined. The results show that the process has the following advantages:high recovery of zinc、pulp had good filtration performance、 short process、easy to implement and control of reaction conditions、the leaching solution containing silicon and iron impurity low without additional processing、low production cost.更多还原