富锗闪锌矿氧压酸浸过程中锗的行为研究

【作者】 梁铎强；

【导师】 王吉坤；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2008， 博士

【摘要】 作为稀散金属,锗因其独特而优良的物理、化学及力学性能,广泛应用于高科技领域,成为重要的战略物资。目前,国内大部分的锗资源是作为富锗闪锌矿冶炼的副产品而得到的。但在常规流程中,流程繁杂,锗的回收率(仅为60%左右)等技术指标很不理想。为此,本课题围绕富锗闪锌矿氧压酸浸过程中锗的行为进行了小型实验室试验研究,试图为氧压酸浸工艺处理富锗闪锌矿的产业化提供理论依据。本课题在查阅了大量国内外文献的基础上进行的,试验工作主要在云南冶金集团总公司技术中心进行,分六大部分：第一部分“富锗闪锌矿氧压酸浸的工艺研究”,第二部分“富锗闪锌矿浸出的机理研究”,第三部分“锌锗浸出差异性的研究”,第四部分“氧压酸浸中锗的浸出动力学研究”,第五部分“银(铁锰)离子对富锗闪锌矿氧压酸浸的、催化作用研究”和第六部分“富锗闪锌矿氧压酸浸液的处理工艺研究”。前五部分是本课题的主体,而第六部分是对前五部分研究的补充。分析化验工作主要由云南省有色金属及制品质量监督检验站完成在第一部分“富锗闪锌矿氧压酸浸的工艺研究”中。利用2升的高压釜对天然的富锗闪锌矿精矿进行了氧压酸浸的正交试验和单因素条件研究,考察了浸出温度、浸出时间、氧压、精矿粒度、酸锌摩尔比和搅拌速度对锗浸出率的影响。在第二部分“富锗闪锌矿浸出的机理研究中,通过预浸出得到比较纯净的(杂质较少)闪锌矿,之后对该矿进行氧压酸浸,实验分添加可溶铁和不添加可溶铁两部分,试图找出富锗闪锌矿浸出的机理。在第三部分“锌锗浸出差异性的研究”中,针对富锗闪锌矿氧压酸浸过程中锗锌浸出率总是存在差异(即锗的浸出率总比锌的低)这一事实,从锗的水解,和硅共沉淀、和铁共沉淀三方面对锌锗浸出差异性进行了的研究。在第四部分“富锗闪锌矿氧压酸浸液的后处理工艺研究”中,人工合成了含锗硫化锌晶体。从添加和不添加疏硫剂(木质素磺酸钠)两部分对此晶体进行了氧压酸浸动力学的研究,试图找出天然富·锗闪锌矿氧化酸浸的动力学模型。在第五部分“银(铁、锰)离子对富锗闪锌矿氧压酸浸的催化作用研究”中,对银铁锰三种离子对富锗闪锌矿氧压酸浸的催化作用进行了研究。铁是以中浸渣的形式添加的。考察了温度等各种因素对催化作用的影响。在第六部分“富锗闪锌矿氧压酸浸液的处理工艺研究”,研究了氧压酸浸后含锗浸出液的处理工艺,包括两部分：一部分是用氢氧化铁沉淀锗的工艺,考察了温度等各种因素对锗共沉淀的影响；另一部分是丹宁沉锗工艺,考察了现存工艺中丹宁锗渣品位低的原因,并研究了如何充分提高丹宁的利用效率在第一部分“富锗闪锌矿氧压酸浸工艺”中,研究了富锗闪锌矿浸出的各种影响‘因素的作用。通过正交试验考察了.6个影响浸出的因素(浸出时间、浸出温度、精矿粒度、酸锌摩尔比、氧压、搅拌速度)对锗浸出的影响,结果表明各因素对锗浸出的影响顺序为：浸出温度>氧压>精矿粒度>搅拌速度>酸锌摩尔比>浸出时间,其中浸出温度和氧压对锗浸出率的影响较大。根据正交试验及单因素试验结果可知,要使锌和锗达到理想的浸出率,较适合的氧压酸浸条件为：浸出温度150℃,氧压1.2MPa,精矿粒度-320目占98.2%(磨矿时间为9min),搅拌速度700rpm,酸锌摩尔比1.5。在此条件下,锌的浸出率在99%以上,锗的浸出率在90%以上元素硫的转化率将近80%,所获得的浸出液终酸的浓度在20g/L左右,铁离子浓度在5g/L左右。在第二部分“富锗闪锌矿氧压酸浸的机理”中使用一种新方法试图找到富锗闪锌矿氧压酸浸的浸出机理。在一定条件下的闪锌矿氧压酸浸中,随着可溶铁的加入量增加,闪锌矿浸出速度加快。经研究表明,在中温(120-160℃)下,硫化氢作为中间产物的机理比较恰当。在第三部分“氧压酸浸过程锗锌浸出的差异”中,从锗的水解、与硅共沉淀和与铁共沉淀三方面考察锗锌在氧压酸浸中浸出率差异的问题。从目前情况来看,和硅的共沉淀是影响最大的因素,其次是和铁的共沉淀,最后是冷却过程中的锗的水解,分别占9%,5%和2%。相对而言,在三种铁沉淀中,黄钾铁矾形式的铁沉淀会造成最大的锗损失,其次是针铁矿,最后是赤铁矿。在第四部分“氧压酸浸中锗的浸出动力学’中,试图找出氧压酸浸中锗的浸出动力学模型。在不添加木质素磺酸钠的情况下,锗的浸出符合“有多孔固体生成的液固反应模型”,该模型的表达式为：在添加木质素磺酸钠的情况下,化学反应是整个含锗硫化锌晶体氧压酸浸过程的控制步骤,该模型的表达式为从拟合结果来看,含锗硫化锌晶体颗粒主要是近似球型或近似立方形,近似圆柱形次之。在第五部分“变价金属离子对富锗闪锌矿的催化作用研究”中,考虑了银、铁、锰三种催化剂对氧压酸浸的催化作用。在特定的条件下,银能促进闪锌矿中锗的浸出。在(闪锌矿+中浸渣)联合氧压酸浸中,它们相互促进浸出。二价锰离子能明显加速闪锌矿的浸出,且催化作用比铁强。在第六部分“富锗闪锌矿氧压酸浸液的处理工艺研究”中,对利用氢氧化铁共沉淀锗、丹宁沉锗工艺做了简单探索。有利于锗铁共沉淀的条件为：高的锗初始浓度高的铁锗摩尔比,高的溶液终点pH,以及低的离子强度,低的中和温度不需要太苛刻的条件便可获取较高的锗沉淀率,这表明利用铁沉淀来达到锌锗分离在工艺上是可行的,具备较好的应用潜力。丹宁几乎和所有的金属具有络合作用。多次使用丹宁能提高丹宁的利用效率,使用过滤的方法能缩短络合时间,提高丹宁的利用效率。本课题的试验结果表明,使用氧压酸浸工艺处理富锗闪锌矿从技术上是可行的。使用该工艺,能获得比常规流程高得多的锗回收率(90%以上),且环境友好,适应性强。为了提高锗的回收率,应加强原料的浸出前处理,严格控制浸出条件和后处理的条件；为了加速浸出过程,可以强化浸出的各种影响因素,使用锰离子作为催化剂加速浸出,必须保证疏硫剂的用量并保护其不被氧化。更多还原

【Abstract】 As a rare metal, germanium is very important material because of its good physic-chemical characteristics, used in high-tech field. The behavior of germanium in acid pressure oxidative leaching of germanium-bearing sphalerite was investigated for the sake of the later industrial application, and to further understanding of pressure leaching.After review of plenty of literature home and abroad, most of experiments were carried out in Technology Center of Yunnan Metallurgy Group Co., Ltd, Kunming. The experiment was constituted of six partS。(1) study on acid pressure oxidative leaching of germanium-bearing sphalerite; (2) study on mechanism of acid pressure oxidative of germanium sphalerite; (3) study on difference of leaching kinetics of germanium and zinc in pressure leaching; (4) leaching kinetics of germanium in acid pressure oxidative leaching of germanium-bearing; (5) catalytic role of silver, iron and manganese in pressure leaching of germanium-rich sphalerite; (6) study on the process to deal with pressure leaching liquor of germanium-bearing sphalerite. The former five parts was the main body, and the latter one part is a supplement. Analysis and determination was done by Yunnan Non-Ferrous Metals & Products Quality Supervision and Analysis Center.In the first part, Lab-scale Orthogonal experiment of autoclave oxidation of germanium-bearing sphalerite concentrate was carried out in a 2-L autoclave to investigate the variables such as leaching temperature, leaching duration, oxygen pressure, granularity, molar ratio of acid to zinc and stirring rate on the dissolution of germanium. In the second part, artificial zinc sulfide crystal was prepared via pre-leaching of nature bearing-sphalerite. Such relatively "pure" sphalerite concentrate was leached in a pressure autoclave, with or without iron ion added. In the third part, the difference in dissolution between germanium and zinc during oxidative pressure leaching of germanium-bearing sphalerite was evaluated in laboratory-scale experiments. The effect of temperature and time on germanium hydrolysis, co-precipitation with silica, and co-precipitation with iron oxides was investigated. In the fourth part, Germanium-bearing zinc sulfide crystal was synthesized; it’s acid pressure oxidative leaching kinetics was investigated under condition with and without sulfur dispersion agent (sodium lignosulfonate) addition. In the fifth part, Catalytic role of dissolved silver, iron and manganese in acid pressure oxidative leaching of germanium-bearing sphalerite was studied. Factors affecting it were investigated. In the sixth part, two processes to deal with pressure leach liquor were studied. One is germanium co-precipitation with ferric hydroxides, factors were investigated. The other is how to scale tannins’utilization.In the first part study on acid pressure oxidative leaching of germanium-bearing sphalerite, variables affecting germanium-bearing sphalerite were investigated such as leaching temperature, leaching duration, oxygen pressure, granularity, molar ratio of acid to zinc and rotation speed on the dissolution of germanium. Orthogonal experiment results showed that leaching temperature and oxygen pressure are major factors affecting the dissolution of germanium, followed by granularity, rotation speed, and molar ratio of acid to ore and leaching duration. The most reasonable conditions were:leaching temperate,150℃, oxygen pressure,1.2MPa, granularity-320mess,98.2%(grind time,9min), stirring rate,700rpm, acid-to-ore ratio,1.5。under such condition, zinc and germanium dissolution yield was above 99%and 90%above, respectively; 80%above sulfur was conversed to elemental sulfur; the final acidity is about 20g/L; iron concentration was about 5g/L. in the second part Study on mechanism of acid pressure oxidative leaching of germanium-bearing sphalerite, a new method was used to investigate the mechanism. Experimental result obtained showed dissolution of sphalerite increased with increased dissolved iron addition, and at medium temperature, the mechanism of hydrogen sulfide is the medium was fitted to experimental result well. In the third part Study on difference of leaching kinetics of germanium and zinc in pressure leaching, the difference of dissolution yield of zinc and germanium was investigated in term of germanium hydrolysis, co-precipitation with silicon, co-precipitation with iron. Experimental results obtained showed the most important factor is co-precipitation with silica, followed by co-precipitation with iron, the finally germanium hydrolysis, and containing 9%,5%and 2%of germanium loss respectively. In the three iron precipitation, jarosite is the most important factor, followed by goethite and hematite. In the forth part leaching kinetics of germanium in acid pressure oxidative leaching of germanium-bearing, attempt to find the kinetics model was tried. When without sodium lignosulphonate addition, diffusion in sulfur lay is the rate-controlling step, and dissolution of germanium is fitted to the model "ash diffusion control-dense-constant size-spherical particles", the equation is When with sodium lignosulphonate addition, chemical reaction is the rate-controlling step, fit the model "chemical reaction control-dense-constant size or shrinking spherical particles" well, the equation From the fitting resuls, most germanium-bearing sphalerite is spherical particles, maybe some are cylindrical particles. In the fifth part catalytic role of silver, iron and manganese in pressure leaching of germanium-rich sphalerite, catalytic role of silver, iron and manganese was investigated. In a given condition, silver ion can accelerate the leaching of sphalerite. In simultaneous leaching of sphalerite and neutral leach residue, they can accelerate each other. Divalent manganese can accelerate the manganese rapidly, and catalytic effect is stronger than iron. In the sixth Study on the process to deal with pressure leaching liquor of germanium-bearing sphalerite, the process of co-precipitation of ferric hydrolysis, germanium precipitation with tannins was investigated. The favor to Ge/Fe co-precipitation conditions are:high initial germanium concentration, high Fe/Ge molar ratio, high final solution pH, and low iron strength, low neutralization temperature. High germanium precipitation yield was achieved in an easy-go condition, which indicated the process has good industrial applicative potential. Tannins can complex with nearly all metal ions. Re-use and multi-use of tannins can scale tannins’utilization.It is technologically feasible to deal with geranium-bearing sphalerite with acid pressure oxidative leaching of sphalerite. Using the process friendlily to environment, higher germanium/zinc can be achieved. To increase germanium recovery yield, it was recommend that pre-treatment, rigid operation condition was done. To shorten the leaching of germanium-bearing sphalerite, manganese and sulfur sphere agency should be added, and guard sulfur sphere agency from being oxidized.更多还原