热还原—真空挥发富集提取锗研究

发布时间：2018-04-30 23:39

本文选题：锗矿 + 热还原　；参考：《上海大学》2016年博士论文

【摘要】：锗是重要的稀缺战略资源,广泛应用于红外光学、光纤通信、航空航天、太阳能电池、核物理探测、化学催化剂等众多国防军工及民用领域,是支撑国民经济发展及国防建设的关键材料,属于我国战略收储金属。世界锗资源仅有美国、中国、加拿大、俄罗斯等国拥有,我国锗资源保有储量仅约3500余吨,占全球锗资源的40.7%;是世界第一大锗生产供应国,高纯锗年产量约130吨,占全球供应量的70%,其中云南锗资源储量占到了全国的32%,产量占到了全国的65%以上,是云南的特色优势产业。云南省临沧地区拥有世界知名的褐煤锗矿资源,褐煤锗矿中锗含量一般在100 g/t~600 g/t之间,经链式锗挥发炉火法冶炼富集后得到锗含量为0.35%~1.50%的低品位锗精矿。本论文主要针对云南临沧地区褐煤锗矿经一步火法富集产出的低品位锗精矿,进行了二次还原挥发富集提取锗研究,以提高锗资源综合利用率,降低生产成本,减小湿法处理的环境影响。重点研究开发了次亚磷酸钠热还原火法挥发富集提取锗矿中锗、次亚磷酸钠热还原-真空挥发富集提取低品位锗精矿中锗的新工艺,以及对产出的还原锗精矿采用碱氧化预处理后经盐酸蒸馏分离提取四氯化锗,再经提纯制备得到高纯二氧化锗的新方法。通过系统性实验对锗矿热还原火法富集、高温常压分段焙烧挥发、次亚磷酸钠热还原真空挥发富集及碱氧化预处理-盐酸蒸馏分离等锗还原挥发过程及原理进行了研究,并分析了锗热还原挥发和碱氧化预处理的工艺原理,最终确定了次亚磷酸钠热还原挥发富集回收锗的工艺条件及参数。首先简要介绍了世界锗资源分布、主要用途、产品产量、生产工艺、主要提取方法。其次对现有锗矿火法富集工艺过程进行了研究分析,对影响锗回收的主要因素如设备、温度、挥发方式及还原气氛等热还原挥发条件进行了剖析,提出了目前锗矿火法富集中存在的锗回收率低等问题及改进方法。经试验提出了在锗矿中添加还原剂次亚磷酸钠进行热还原挥发来提高锗矿火法冶炼回收率的方法,通过添加2.5%的次亚磷酸钠能把锗挥发率从91%提高到接近100%,挥发残渣中锗品位降低至50 g/t.重点对次亚磷酸钠热还原-真空挥发富集锗的工艺方法进行了系统性试验研究,并与常压高温分段焙烧挥发富集方法进行了比较分析,通过实验对产出的高品位还原锗精矿中锗的碱氧化预处理-盐酸蒸馏分离提取方法进行了深入研究。通过自行设计的锗还原挥发炉,采用正交实验及单因素条件实验,进行了系统性研究分析,同时采用热力学方法原理及扩散理论对还原反应及真空挥发过程进行分析。通过对还原剂的选择,还原反应过程,挥发原理等方面的研究分析,优选出最佳工艺条件为:挥发温度1000℃,次亚磷酸钠用量7.5%,真空度500 Pa,载气流量2 L/min,挥发时间90 min,料层厚度30 mm,此条件下锗挥发率达到94.76%~98.35%,挥发残渣中锗含量达到0.06%~0.13%,产出还原精矿品位达到12.68%~46.71%,富集倍数达27~36倍。与常压挥发富集方法相比,还原挥发温度低200℃,挥发时间短60分钟,富集倍数提高了10~14倍,锗挥发率提高了22%~32%,富集得到的精矿锗含量提高了5%~19%,具有显著的锗回收效果,同时生产成本得到了大幅下降。自行设计了含锗原料提锗实验装置,提出了采用氢氧化钠+过氧化氢氧化预处理-盐酸蒸馏分离得到四氯化锗,再经传统工艺精馏提纯水解后得到高纯二氧化锗的新工艺,解决了本方法得到的高品位还原锗精矿在用常规湿法盐酸蒸馏提锗工艺回收率低的难题。通过系统研究,优选的工艺参数为:水用量为锗精矿重量的2倍,氢氧化钠用量为锗精矿重量的30%,过氧化氢(30%)用量为锗精矿重量的25%,预处理时间为1.5 h,蒸馏盐酸用量为锗精矿重量的9倍。本方法能够显著提高锗的盐酸蒸馏回收率,采用本工艺后锗回收率提高到了97.90%以上,而用常规盐酸蒸馏工艺回收锗时回收率才能达到65.16%.相对于目前的硫酸浸出-丹宁沉淀-盐酸蒸馏分离的湿法提锗工艺,本方法具有锗回收效率高,流程简短,设备简单,可操作性强,辅料消耗少,生产运行成本低,避免了大量废水、废气和废渣的排放及处理,可彻底解决湿法处理工艺提锗带来的环境污染问题。研究结果表明,使用本工艺回收锗矿及低品位锗精矿中的锗是可行的,具有回收率高,环境友好,适应性广等特点,达到了提高锗综合回收率,降低生产成本,节能减排,安全环保,高效利用锗资源的目的。本文的研究成果拓展了次亚磷酸钠热还原真空挥发富集回收锗和碱氧化预处理蒸馏分离提取锗新技术在稀有金属领域的应用范围,具有广阔的应用前景。
[Abstract]:Germanium is an important scarce strategic resource. It is widely used in infrared optics, optical fiber communication, aerospace, solar cells, nuclear physics detection, chemical catalyst and many other defense industry and civil fields. It is the key material to support national economic development and national defense construction. The country owned by Da, Russia and other countries, the reserves of germanium resources in China are only about 3500 tons, accounting for 40.7% of the global germanium resources. It is the world's largest germanium production supply country. The production of high pure germanium is about 130 tons, accounting for 70% of the global supply. The Yunnan germanium reserves accounted for 32% of the country, and the output accounted for more than 65% of the country. It is the characteristic advantage of Yunnan. Industry. The Lincang area of Yunnan province has the world famous lignite germanium mineral resources, the germanium content in the lignite germanium is generally between 100 g/t~600 g/t and the low grade germanium concentrate with the germanium content of 0.35%~1.50% after the chain germanium volatilization process is enriched. This paper mainly focuses on the one step fire enrichment and the production of the lignite germanium in Lincang area of Yunnan. The low grade germanium concentrate has been studied by two times reduction and volatilization to extract germanium, in order to improve the comprehensive utilization of germanium resources, reduce the production cost and reduce the environmental impact of the wet process. The emphasis is on the extraction of germanium in germanium from the evaporation of sodium hypophosphite by heat reduction and fire method, and the extraction of low grade germanium by the thermal reduction of sodium hypophosphite and vacuum evaporation. The new process of germanium in concentrates, and the extraction of germanium chloride from the produced germanium concentrate by alkaline oxidation pretreatment, four germanium chloride is distilled by hydrochloric acid, then a new method of high purity two germanium oxide is prepared by purification. Through systematic experiment, the germanium ore is enriched by heat reduction fire method, volatilization and evaporation of sodium hypophosphite by heat reduction, and vacuum volatilization of sodium hypophosphite. The process and principle of the reduction and volatilization of germanium by Preconcentration and alkali oxidation pretreatment, such as hydrochloric acid distillation, are studied. The process principle of germanium thermal reduction volatilization and alkali oxidation pretreatment is analyzed. The technological conditions and parameters of the recovery of germanium by thermal reduction and volatilization of sodium hypophosphite are finally determined. The distribution of germanium resources in the world is briefly introduced. The main factors affecting the recovery of germanium, such as equipment, temperature, mode of volatilization and reduction atmosphere, are analyzed, and the low recovery rate of germanium in the rich concentration of germanium fire method is put forward, and the low recovery rate of germanium is put forward. By adding 2.5% of sodium hypophosphite, the volatilization rate of germanium can be increased from 91% to 100%, and the germanium grade in the volatile residue is reduced to 50 g/t. by the addition of sodium hypophosphite in the germanium. The process method of vacuum evaporation and enrichment of germanium has been systematically studied and compared with the method of volatile enrichment in high temperature high temperature section roasting. The method of separating germanium from high grade germanium concentrate by alkali oxidation pretreatment with hydrochloric acid distillation is studied through experiments. Using orthogonal experiment and single factor condition experiment, a systematic study and analysis are carried out. At the same time, the thermodynamic method principle and diffusion theory are used to analyze the reduction reaction and vacuum evaporation process. Through the research and analysis of reducing agent selection, reduction reaction process, volatilization principle and so on, the optimum process conditions are as follows: volatilization is: volatilization The temperature is 1000 C, the amount of sodium hypophosphite is 7.5%, the vacuum degree is 500 Pa, the air flow rate is 2 L/min, the volatilization time is 90 min, the thickness of the material layer is 30 mm. The germanium volatilization reaches 94.76%~98.35% under this condition, the germanium content in the volatile residue reaches 0.06%~0.13%, the output of the reduced concentrate reaches 12.68%~ 46.71% and the enrichment multiplier reaches 27~36 times. Compared with the reduction volatilization temperature 200 c, the volatilization time was 60 minutes shorter, the enrichment factor increased by 10~14 times, the germanium volatilization rate increased by 22%~32%, the enriched germanium content increased by 5%~19%, the germanium recovery effect was remarkable, and the production cost was greatly reduced. The germanium containing germanium experiment device was set up by ourselves, and the use of hydrogen and oxygen was proposed. A new process of high purity two germanium oxide was obtained after distillation and hydrolysis of four germanium chloride by sodium hydroxide + hydrogen peroxide oxidation pretreatment and hydrochloric acid distillation. The problem of low recovery rate of high grade germanium concentrate obtained by this method in the process of distilling germanium by conventional hydrochloric hydrochloric distillation was solved. The parameters are: 2 times the weight of the germanium concentrate, 30% of the weight of germanium concentrate, 25% of the weight of germanium concentrate, 1.5 h and 9 times the weight of germanium concentrate. This method can improve the recovery rate of salt and acid distillation of germanium significantly, and the recovery rate of germanium after this process is improved to this process. More than 97.90%, and the recovery rate of Germanium Recovery by conventional hydrochloric acid distillation process can reach 65.16%. relative to the wet process of extracting germanium from the current sulfuric acid leaching - Denning precipitation hydrochloric acid distillation. This method has high efficiency, short process, simple equipment, strong operability, less excipient consumption, low production cost, and avoided a large amount of operation. The discharge and treatment of waste water, waste gas and waste residue can thoroughly solve the environmental pollution caused by the extraction of germanium in the wet process. The results show that the recovery of germanium in germanium and low grade germanium concentrate by this process is feasible, with high recovery, friendly environment and wide adaptability, which can improve the comprehensive recovery rate of germanium and reduce the production of germanium. Cost, energy saving, emission reduction, safety and environmental protection, and efficient use of germanium resources. The research achievements of this paper expand the application scope of new technology in the field of rare metals with the thermal reduction vacuum evaporation, vacuum evaporation and recovery of germanium and alkali oxidation, and the extraction of germanium in the rare metal field.

【学位授予单位】：上海大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN304.11

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