从含锗烟尘浸出与萃取锗研究

【作者】 梁杰；

【导师】 王华；

【作者基本信息】 昆明理工大学 ， 冶金物理化学， 2009， 博士

【摘要】 贵州拥有丰富的伴生稀散金属锗和贵金属银的低品位氧化铅锌矿资源。该矿经烟化法富集得到品位为Zn 35%-45%、Pb 22%-28%、Ge350g/t-500g/t的含锗烟尘。本论文对该烟尘中锗、锌的浸出过程与萃取分离锌锗过程进行研究,以期为该烟尘的综合回收提供合理的工艺参数,为开发利用该类资源奠定基础。本论文扼要介绍了锗的资源概况、研究开发、生产技术、主要用途及发展动态。近年来,国内外对含锗物料的浸出工艺做了大量的研究,国内多家单位先后对各种含锗原料如煤、烟尘、矿渣的浸出技术与新工艺作了研究。本论文以贵州含锗烟尘为原料,对其浸出过程进行了理论分析和新工艺研究。以TOA为萃取剂、酒石酸为配合剂、TBP为调相剂对浸出液进行萃取分离锗、锌的工艺技术与萃取锗的机理研究。本论文为实验室研究,运用冶金物理化学方法对浸出与萃取过程进行研究。技术路线为：低品位含锗氧化铅锌矿→烟化法富集→锗烟尘浸出(实现锌锗与铅银分离)→浸出液萃取(实现锌锗分离),浸出渣作为提取铅银的原料,锌锗分离后的溶液分别提取锌和锗。实验采用硫酸作为浸出剂。运用优选法确定适宜浸出工艺条件为：搅拌强度：120r/min;浸出时间：3 h；浸出温度：90℃；液固比：8/1；始酸浓度：120g/L。对浸出过程进行热力学分析,得知含锗烟尘中主要组分的行为：锗、锌主要进入溶液；而铅银留在渣中。浸出实现了锗、锌与铅、银的有效分离、富集。二氧化硅、含锗烟尘中的铁、铜、镉、砷和少量氟化物、氯化物在浸出条件下能够溶解进入溶液。从浸出液中分离锌锗,工业上主要采用的方法是丹宁沉淀。本论文采用萃取方法,选用TOA为萃取剂,酒石酸C4H606为配合剂,TBP(C12H27O4P)为调相剂,磺化煤油为稀释剂进行萃取。选用NaOH为反萃剂,系统研究了从锗烟尘浸出液分离锗与锌的工艺技术条件。实验结果表明：本工艺流程短,选择性好,锗回收率高,所用试剂价廉易得。通过一级萃取和一级反萃取,锗萃取率大于97%、几乎不萃取锌,测算出了锌与锗的分离系数；再经一级反萃取,锗反萃取率大于95%,实现了锌锗高效分离及锗的富集。在弱酸条件下,锗主要以H2GeO3的形态存在。直接用胺类萃取剂[CH3(CH2)7]3N萃取锗时,锗萃取率非常低。向水相中添加配合剂酒石酸(C4H6O6)能与锗形成离解度较大的配合阴离子。配合阴离子半径越大、电荷数越低、水合程度越低,越易转入有机相,有助于提高锗的萃取率。有机相中萃取剂应先在酸性条件下转型为胺盐,才能完成萃取。水相中阴离子半径越大、电荷越低,越容易与有机相的胺盐阳离子结合,所以锗—锌能被高效分离。显然Ge(C4H4O6)32-比H2GeO3更易与胺盐中阳离子进行离子缔合而置换HSO4-。加入调相剂能消除萃取过程出现第三相,改善体系性质,并有助于对锗的萃取。选用强碱NaOH作为反萃取剂,研究了反萃取的工艺条件。研究结果表明：(1)选用萃取剂TOA30%～调相剂TBP5%～稀释剂65%作为有机相萃取体系,先用硫酸把萃取剂转为胺盐。水相中加入配合剂酒石酸把锗转为半径较大的配合阴离子,进行萃取。一级萃取工艺条件为：相比O/A=1/8;配合剂与水相中锗的质量比为12～16；常温。锗一级萃取率大于97%,几乎不萃取锌,实现了锌-锗高效分离(2)用30%的NaOH溶液作反萃剂,相比O/A=2；常温反萃,锗一级反萃率大于95%。本论文提出的一段浸出、中和、一段萃取、一段反萃处理锗烟尘的新工艺具有流程简短、锗回收率高、锌-锗分离完全、并能够富集铅银、萃取剂可损失少并可循环使用等特点。运用等摩尔法结合红外光谱分析确定了萃合物的组成,得出如下结论：(1)三辛胺(TOA)萃取锗属于阴离子交换机理；(2)调相剂TBP的作用除有效防止第三相生成外,还具有一定的协同萃取作用；(3)锗配合阴离子与萃取剂TOA的摩尔比为1：2,萃取产物是{[CH3(CH2)7]3NH}2·[Ge(C4H4O6)3](O)。更多还原

【Abstract】 It is rich in natural resource of zinc oxide and lead oxide ore in Guizhou Province, which contains a little of germanium and silver. There are 210 thousand tons of available metals only in Zhazichang Mine. A fuming process is adopt for enriching of low-grade lead-zinc oxide ore to produce germanium oxide dust which contains Zn 35-45%、Pb 22-28%、Ge 350-500g/t.That is important raw material to recover germanium. An investigation of leaching process of germanium dust and separating germanium from zinc in the solution by extraction has been made for further making use of the resourceA mass of research has been made on the technics of leaching process of germanium recent year oversea and at home. The research of kinetics of leaching germanium is correspond less. Some universities and smeltery have researched on the aspect of thermodynamics and kinetics to leaching process of coal, dust, slag and ore.The leaching process of germanium dust is studied in this work. According to the analysis chart of x-ray diffraction and chemical phase, it was found that Zinc and lead exist mostly in oxide minerals. Germanium exists mainly in germanium dioxide, less in germinate in the dust. Under acidic condition, the fraction of infusible germanium, which exists in tetragonal system, accounts for 9.88% of the total germanium. Thermodynamics analysis and kinetics research to leaching process of the dust are carried through. The technological condition to separate germanium from zinc in the lixivium by TOA and its mechanism are also carried through.This work is laboratory test. An investigation of leaching process of the dust and extracting process are carried by method of metallurgical physical chemistry. The research plan is:leaching of the dust(for separating zinc and germanium from lead and silver)——extracting of germanium by TOA(for separating germanium from zinc). Leached residue is raw material to extract lead and silver. The work studies the affect on leaching process of temperature, leaching time, stirring speed, solid to liquid ratio and acid concentration. And it also studies kinetics to leaching process of zinc oxide and germanium dioxide. Based on the experiments, the favorable conditions were reaction temperature of 363K, leaching time of 2.5h, stirring speed of 120r/min., solid to liquid ratio of 1/8, and acid concentration of 120g/L. Under these conditions, the leaching and recovery rate of germanium should be more than 87%. It should be improved by increasing the concentration of sulfuric acid and temperature. Meanwhile, Zinc was dissolved into liquor, and lead and silver stayed in the residue, which made them easily to be separated.optimum conditions of germanium extractions have been investigated from the leaching solutions of germanium dust by using a kind of extractant TOA, complexing agent C4H6O6and improving reagent C12H27O4P, in addition to kerosene as diluent and NaOH as stripping agent. The results show that this process has the following advantages:simplicity in flowsheet, good selectivity, high recovery and availability of the reagents. Through one step extraction and one step back wash extraction, germanium extraction rate is more than 97%. In the process it is hardly extraction of zinc. Separating coefficient to germanium and zinc is estimated. Stripping rate is more than 95%. It is convenient for the sake of recovering zinc and germanium.Germanium exists in state of H2GeO3 in the weak acid. Because of its small dissociation constant k1=1×10-9, k2=3.98×10-23, So there are low concentration of HGeO3- and GeO32-.germanium extracts into organic pHase in ion state. If it is extracted by TOA, germanium extraction rate is very low. When appending complexing agent C4H6O6, it can form anion with germanium which possess big dissociation degree. The reaction is as follow:3C4H6O6+H2GeO3=Ge(C4H4O6)32-+2H++3H2O Extractant TOA is first changed into amine salt. The reaction is as follow:[CH3(CH2)7]3N(O)+H2SO 4(A)=[CH3(CH 2)7]3NH 2SO 4(O)The extraction reaction is as follow:2[CH3(CH2)7]3NH2SO4+H2Ge(C4H4O6)3 ={[CH3(CH2)7]3NH}2·[Ge(C4H4O6)3](O)+2H2SO4(A)The stripping reaction is as follow:2{[CH3(CH2)7]3NH}·[Ge(C4H406)3](O)+2NaOH = Na2[Ge(C4H4O6)3](A)+2H2O(A)+2[CH3(CH2)7]3N(O)The optimum extraction conditions are TOA 30%, improving reagent 5%, diluent 65%. O/A=1/8, mass ratio of complexing agent to germanium 12-16, and at normal temperature,3-5 min.The optimum back extraction conditions are NaOH concentration 30%, O/A=2, and at normal temperature,3-5 min.The extraction compound is determined by infrared spectrum analysis and equal molar method. As a result some conclusions can be gotten. (1) TOA extracting germanium belongs to anion exchange mechanism. (2) The action of TBP is for preventing to form the third pHase in extraction process. and it is still in favor of extracting germanium. (3) The molar ratio of germanium complexing anion and extractant is 1:2. The extraction compound is{[CH3(CH2)7]3NH}2·[Ge(C4H4O6)3](O).更多还原