从含锌铟复杂物料中提取金属铟新工艺的研究

【作者】 刘大春；

【导师】 戴永年； 杨斌；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2008， 博士

【摘要】 稀散金属铟由于具有十分独特而优良的物理和化学性能,成为了现代电子工业中最重要的材料之一,全球金属铟60～80%用于制造ITO透明导电膜,而ITO是目前性能最好的导电膜材料,暂时还无其它材料可比拟、代替。因此,金属铟支撑着全球为数巨大的平板电视、计算机、手机等各种尺寸显示器的生产,在国民经济中有重要的作用。我国铟资源十分丰富,已探明储量世界第一,主要集中于西部地区的广西、云南、内蒙古和青海等地。在火法炼锌中年产约3万吨富含锌铟的物料,其中含锌2.4万吨,含铟100吨,综合利用价值很高。长期以来,这种含锌铟物料缺乏高效先进的处理技术,现有方法生产铟的回收率低,有的甚至不到50%。因此从这种含锌铟物料中高效提取锌铟新技术的研究开发具有重要意义。在本论文中针对火法炼锌得到的一种含锌铟物料,通过分析物料的物相和性质,在查阅大量资料、对比多种处理方法的基础上提出了真空蒸馏、湿法浸出、净化、富集、置换、电解提纯多项技术相结合的新工艺,并对其中的关键技术进行了理论及应用基础研究和实验：(1)从理论上研究了金属在真空条件下的蒸发、冷凝、杂质分离的理论基础及过程,计算了铟与主要杂质元素的分离系数、挥发速率、气液相成分及气液相平衡图。然后在此基础上进行了含锌铟物料及粗铟的真空蒸馏实验,考查了含锌铟物料回收锌、富集铟的相关指标、工艺条件,粗铟蒸馏中铟及杂质元素的走向、分布规律等。得到的相关指标和操作条件用于下一步的工业化设计和应用；(2)研究了铟水系的电位φ—pH图、浸出置换过程的理论基础及过程热力学、动力学基础及浸出反应的活化能等相关计算,进行了富铟渣浸出过程、置换过程的相关试验,考查了酸度、液固比、时间、温度等因素对铟浸出率的影响,置换剂的选择、粒度、温度、时间对置换率的影响,得到了相关参数；(3)根据电解的基本原理讨论了影响电解的诸多因素并进行了小型实验,得到了可靠的技术参数；(4)对粗铟的真空蒸馏进行了小型(100g)、扩试(20kg)及工业化(200kg)试验,开发了不同处理量的专用设备。理论及实验研究得到了各工序最佳的工艺条件为：1)含锌铟物料真空蒸馏：蒸馏温度900～950℃,炉内压力小于100 Pa,冶炼时间16-20h,金属锌回收率97%,金属铟回收率99%,金属铟富集倍数7倍。2)富铟渣浸出：分为中性浸出、酸性浸出两段①中性浸出：液固比6～8:1；温度：80～90℃；时间：6小时左右；始酸为：120～150g/l H2SO4；终酸为：PH=5.0～5.4。②酸性浸出：液固比8～10:1；温度80～90℃；浸出时间为12小时左右；始酸为：150～200g/l H2SO4；终酸为：PH≤1.5。3)锌粉置换的工艺条件为：锌粉和金属铟的质量比1.1:1,置换时间72h,置换温度≥20℃,pH值1～1.5,锌粉含锌99.9%以上,粒度80～120目。4)粗铟(95～99%In)真空蒸馏的工艺条件为：温度750～850℃,真空度小于10 Pa,锌镉去除率大于98%,可取代化学法。5)粗铟(～99%In)电解精炼的工艺条件为：电流密度80A/m2槽电压0.25-0.35v同极中心距70mm电解周期阳极周期14～21天,阴极周期5～7天电解液温度20～30℃电解液成分(g/l)如下：电解后可得到含铟大于99.99%(4N)精铟。其创新点包括：①集成创新了提取金属锌、铟新工艺；②含铟物料的真空蒸馏技术；③富铟渣两段浸出、锌粉置换制备海绵铟技术；④粗铟真空蒸馏和电解精炼联合生产精铟技术；⑤与新技术配套的真空冶金装备的研制。并进行了规模为10吨/年精铟工业化设计及实验。实践证明该工艺具有技术集成度高、流程短、铟的回收率高、生产过程对环境友好等特点。至今整套工艺技术和装备在云南省建成年产10吨/年精铟的生产线,2004年成功实现了产业化应用,该工艺中的部分关键技术和装备还应用于国内几家炼铟企业。截止2006年底利用该技术共生产99.993%精铟62吨,金属锌5000多吨,新增产值5亿多元人民币,其中创外汇810万美元,实现利税近1亿元人民币。并和拥有最大铟资源的企业—云南华联锌铟股份公司签订协议开始实施利用该技术在2008年建成亚洲最大铟生产工厂(年产铟60吨/年)。该工艺创新性强,拥有自主知识产权,已获得国家发明专利3项。经有关专家鉴定,一致认为整体技术属国内外首创,达到国际先进水平。2007年获得中国有色金属工业协会科技发明一等奖,云南省科技发明一等奖。总之,该课题研发的提铟新技术有广阔的推广前景,能够实现含铟矿产资源的综合高效合理利用,实现金属铟清洁生产。同时为稀散金属的真空冶炼起到一定的示范作用,尤其是对提纯稀散金属及其高纯产品生产也有一定的推广应用前景,对有色金属冶金工业的科技进步有着积极的意义。更多还原

【Abstract】 Scattered metal indium with unique and excellent physical and chemical properties has become one of the most significant support materials in the modern electronics industry. Sixty to eighty percent of global gross output of indium has been applied to the manufacture of ITO transparent conductive film, which is the best conductive film material and has no alternative to be compared or replaced at present. Therefore, tremendous support of the global production of displays with various size including flat-panel TVs, computers, cell phones, etc. with indium, and thus plays increasingly important role in the national economy.As China is rich in indium resource which ranks first in the world, indium resources mainly concentrated in the western regions including Guangxi, Yunnan, Neimenggu and Qinghai etc. The annual output of the materials with rich zinc and indium is about 30,000 tons by pyrometallurgy. It contains zinc 24,000 tons and indium 100 tons, which contribute to its high value of comprehensive utilization. Nevertheless, for a long time there has been little efficient and advanced processing techniques to treat such materials with zinc and indium. Accordingly to study and develop the new technologies of efficient extraction of indium and zinc from such materials with zinc and indium is of great significance.According to the materials with zinc and indium by pyrometallurgy in this thesis, a new process was proposed on the basis of the analyzing the phases and properties of the materials, referring to a large number of datas and comparing with a variety of treatment, which combined vacuum distillation, wet leaching, purification, enrichment, replacement, and electrolysis purification. The key technologies as indicated above were also studied in terms of theoretical research, applied basic research and experimental study. (1)The principle, mechanism and thermodynamics, kinetics of metal evaporation, condensing, impurity separation was studied in theory firstly, and the separation coefficient, evaporation rate, gas composition and gas-liquid equilibrium diagram of indium and main impurities were calculated. Then the vacuum distillation tests of the materials with indium and crude indium were carried out on the basis hereinabove, which examined the related indicators and process conditions of zinc recovery and indium enrichment from the materials with indium and zinc, and the trend and distribution of impurity elements in the distillation of crude indium. The relevant indicators and operating conditions can be applied in for the following of industrial design and application. (2)Electrode potential-pH diagram based on indium, mechanism, process thermodynamics and kinetics of leaching replacement process were studied, which includes rich indium slag leaching, related tests of the replacement process. The influences of the acidity, liquid-solid ratio and time on the rate of extraction of indium and the influences of the replacement of choice, size, temperature and time on the replacement rate were also observed, and related parameters were obtained. (3) Through the small-scale tests in the process of electrolysis in accordance with the basic principles of electrolysis, reliable technical parameters were gained. (4)On the basis of the small-scale test(100g), bench-scale test(20kg) and industrial test(200kg) of vacuum distillation of crude indium, appropriative equipments with different capacity were developed.The operating parameters of the process-were determined by theory and experimental research as follows:1) Vacuum distillation of the materials with indium and zinc:distillation temperature: 900-950℃, furnace pressure:<100Pa, smelting time:16-20h, recovery rate of indium: 97%, recovery rate of zinc:99%, multiple of indium enrichment:7 times.2) Leaching of slag with rich indium was divided into neutral leaching and acid leaching:①NNeutral leaching:ratio of liquid-solid:6-8:1, temperature:80-90℃,time:about 6 hours, before acid:H2SO4120-150 g/l; end acid:PH= 5.0～5.4.②Acid leaching:ratio of liquid-solid:8-10:1, temperature:80-90℃, time:about 12 hours, before acid:H2SO4150～200 g/l, end acid:PH≤1.5.3) Process conditions of the replacement of zinc powder:mass ratio of zinc powder and indium, replacement time:72h, replacement temperature:≥20℃, pH:1～1.5, zinc content in zinc powder:>99.9%, particle size:80～120 mesh.4) Process conditions of vacuum distillation of crude indium:temperature:750-850℃, degree of vacuum:<10Pa, removal efficiency of zinc cadmium:>98%, as replacement of chemical methods.5) Process conditions of electrolytic refining of crude indium: Current density:80 A/mCell voltage:0.25～0.35VCenter distance between two electrode with same electrode:70 mmElectrolysis cycle:anode cycle 14-21 days, cathode cycle 5-7 daysElectrolyte temperature:20-30℃Composition of electrolyte(g4) are as follows:Fine indium with indium content more than 99.99%(4N) can be obtained after the electrolysis of indium.Its key point of innovation cover 5 items:①The integrated innovative new process of the extraction of the metal zinc and indium;②The technology of vacuum distillation of the materials containing indium;③Slags with rich indium were leached by sulfuric acid in two steps including neutral and acid leaching, and sponge indium was thus prepared by the replacement of zinc powder;④The technology of refined indium production combining vacuum distillation of crude indium with electrolytic refinement;⑤Vacuum equipments matched with the new technology. In addition, industrial design and experiment of refined indium with the scale of 10 tons per year of indium fine design and industrialization has been proceeding. Practices prove that the new technology developed has many advantages including high technical integration, short flow, high recovery rate of indium and little pollution.So far product line of refined indium with annual output of 10 tons/year was built in Yunnan Province by the integrated process technologies and equipments which realized industrial application successfully in 2004. Part of the key technologies and equipments in this process was also applied in several domestic enterprises of refining indium. Up to the end of 2006, the output of the refined indium(99.993%) has achieved 62 tons while the output of zinc has reaches over 5,000 tons, and the output value has increased by 500 million yuan, which covers foreign exchange 8.1 million US dollars and profits and taxes nearly 100 million yuan. Under the cooperation with the enterprises which owns the greatest resources, Asia’s largest indium-production factories (annual output of indium 60 tons/year) are prepared to be built by virtue of this technology.This innovative technology with autonomous intellectual property rights were authorized 3 state invention patents. Identified by the relevant experts, the integrated technology was agreed that it’s the pioneer technology at home and abroad and has reached the international advanced level. Besides, this technology has won the first prize of China Nonferrous Metal Industry Association for scientific and technological inventions and first prize of scientific and technological inventions in Yunnan Province in 2007.In conclusion, this technology has a vast range of prospects for promotion and popularization, and can realize the comprehensive efficient reasonable utilization of the mineral resources and clean production of metal indium. Meanwhile it plays a demonstrative role for vacuum smelting of scattered metals, especially for the promotion and popularization of the purification of scattered metals and high-purity products. Furthermore, there’s positive meaning for the scientific and technological progress of non-ferrous metallurgical industry.更多还原