【作者】 蓝德均；

【导师】 张旭； 朱祖泽；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2003， 硕士

【摘要】 本文研究了硫酸锌溶液中杂质钴的去除。对于硫酸盐溶液中的Co²⁺的分离的常规方法，视不同的金属生产工艺而异。锌湿法冶金中硫酸锌溶液中的杂质钴是用锌粉加一些活化剂进行置换而除去，这将产出含锌很高的高钴渣，它难于进一步地处理回收相关的有价元素。在镍冶金中镍电解液或硫化镍湿法浸出液中钴的净化则采用氯气法或黑镍法。但这两种方法不能用于硫酸锌溶液中净化钴，因为它们会在硫酸锌溶液中引入氯离子或镍离子，这两种离子对锌的生产来说都是十分有害的杂质元素。所以这三种方法都不能用于硫酸锌溶液中除钴，尤其是不能用于锌湿法冶金工业中硫酸锌上清液钴净化所产的高钴渣（锌钴渣）的硫酸浸出液中再次分离钴。所以需要提出一种新的从硫酸锌溶液中除钴的方法。 经过实验研究，提出了高锰酸钾氧化法用于硫酸锌溶液中除钴。虽然Co²⁺比较难被氧化，但在高PH、高温和使用诸如氯气、黑镍、高锰酸钾等强氧化剂的条件下还是可以氧化的。当Co²⁺被氧化成高价态时，由于Co³⁺十分不稳定极易水解沉淀而从溶液中除去。在较高的PH条件下，用高锰酸钾可以实现钴的氧化沉积。与其它的氧化剂氧化沉钴不同的是高锰酸钾的还原产物是难溶于水的固相。然而，类似于其它的氧化剂的氧化反应，高锰酸钾氧化沉钴的过程中也会产生氢离子使体系的PH下降，从而减缓、中止甚至可使反应逆向进行。所以在氧化沉钴过程中必须加入中和剂与生成的氢离子反应以使体系的PH基本不变。从实验研究中得出的氧化沉钴的条件为：PH＞4.0，温度75℃，反应时间30—60min。 研究中首先进行了在纯硫酸钴体系下高锰酸钾的氧化沉钴实验，然后再从锌钴渣的硫酸浸出液中氧化除钴。在纯体系下，考查了反应温度、反应时间、体系PH、高锰酸钾加入量和诸如Mn²⁺，Ni²⁺，Zn²⁺和Cd²⁺这四种杂质对高锰酸钾氧化沉钴效果的影响。研究发现，温度越高，时间越长，PH越高和高锰酸钾加入量越大，则氧化沉钴的效果就越好。这其中，PH是一个很关键性的影响因素，如果溶液的PH维持得足够高的话，温度和时间对沉钴效果的影响就很小了。在所考查的杂质中，Mn²⁺将会和高锰酸钾进行比较完全的反应，Ni²⁺只会部分地被氧化，而Zn²⁺和Cd²⁺则不与高锰酸钾反应。但是，如果杂质离子在溶液中的浓度很高的话，它们所形成的大的离子强度将会影响溶液中各溶解物种的活度，从而使得与纯硫酸钴体系下相比要达到同样的除钴效果就需要更高的残余高锰酸钾浓度。经钴氧化产物的X射线衍射分析和电位实验结果分析，高锰酸钾和钴的反应的产物主要高锰酸钾氧化沉钻的研究及应用2003年5月为co00H和Mn02，反应中c矿+和KMno;的摩尔比约为3。在纯硫酸钻体系研究的基础上，将高锰酸钾氧化法应用于高钻渣的硫酸浸出液中除钻，获得了相应的较好的沉钻操作条件如下:残余高锰酸钾浓度19/I，用以控制溶液PH的氧化锌的过量浓度为79/1，反应温度为75℃，反应时间3。6omin。 综上所述，使用高锰酸钾氧化法从硫酸锌溶液中除钻具有如下一些优点:（1）可产出钻品位高于12%的钻精矿，利于钻的回收;（2）除钻的效果好，溶液残钻浓度可低于lmg月;（3）除钻操作时间短，如上所述为30一6omin;（4）与其它在工业上用过的除钻方法相比，其成本较低;（5）不会引入其它的有害杂质;（6）易于和现有的锌湿法流程相结合;（7）综合实现了经济效益和环境效益。因此，高锰酸钾氧化沉钻法是一个适用于处理高钻渣回收锌钻等有价元素的良好工艺。更多还原

【Abstract】 In this paper, a new method of removing cobalt from zinc sulphate solution is researched. In hydrometallurgy process, conventional removing cobalt method are zinc powder cementation in zinc production, and chlorine and nickelic compound oxidation precipitation in nickel production. But in first process, high grade zinc residue is produced, which is treated difficultly and in other two methods, chlorion or nickel ion will be inducted, so they can be only used in nickel hydrometallurgical processes. Therefore, above three methods are not suitable for acquiring commercial cobalt raw material in removing cobalt from zinc sulphate solution. So, a new process must be investigated.In the research, potassium permanganate is used to remove cobalt. The way of its removing cobalt is oxidation. Though cobaltous ion is oxidized uneasily, it can be fulfilled under the special conditions: higher solution PH, higher temperature and stronger oxidants such as chlorine, nickelic compound, permanganate, etc. When cobaltous ion is oxidized into cobaltic ion, it can be separated from solution as an insoluble deposit, for cobaltic ion hydrolyzes easily at PH>4.0. Hence, as a very strong oxidant, potassium permanganate can precipitate cobalt. Differing from other oxidants,the product of reacted permanganate is insoluble in oxidation process. The reaction between permanganate and cobaltous ion will produce hydrogen ion, consequently the PH of the reaction system will decrease when reaction is doing. Under low PH, the reaction doesn’t take place, contrary, cobaltic compound will be reduced into cobaltous ion, and neutralizing agent must be added into the system to neutralize hydrogen ion.In order to determinate the preferable conditions of above reaction, the research is carried out, firstly, with cobaltous sulphate solution, then on the base of it, with the leaching solution of Zn-Co residue from cobalt purification from zinc hydrometallurgical smelter. With cobaltous sulphate solution, the influences of temperature, time, PH, potassium quantity and impurities including Mn2+, Ni2’1", Zn2+ and Cd2+ are researched. It is found that higher temperature, longer time, higher PH and more potassium are beneficial to cobalt precipitation. Thereinto, PH is a key factor, and when PH is high enough, temperature and time have a little affection on reaction. Of impurities, Mn24 can react with permanganate completely; Ni2+, partly; Zn2+ and Cd24, never. When ionic strength is high, the activities of all ions in the solution are influenced. In general, the activities decrease. Therefore, the residual concentration of potassium in the solution with high impurities ionic strength is higher than one in the solution with the same cobaltous ion concentration and without other impurities at the same rate of the cobalt removal. Then, the stoichiometric ratio of the reaction between cobaltous ion and permanganate is determined by potentiometry and X-ray diffraction of the product of the reaction. The results show that the reduced compound of permanganate is mainly Mn02, and the oxidized one of Co2+ is CoOOH, and the molar ratio between cobaltous ion and permanganate is about 3.0. On the base of those, cobalt removal from the leaching solution is investigated. The parameters for cobalt removal of the leaching solution are determined as follows: superfluous concentration of permanganate is lg/1; superfluous concentration of ZnO is 7g/l (used to consume hydrogen ion to retain PH of solution); temperature is 75 C; reaction time is between 30min and 60min.Thus, high cobalt raw material with commercial value can be obtained from this method, in which cobalt concentration is higher than 12%. Besides it, the method has such merits: the rate of cobalt removal is more than 99% and the residual cobalt concentration in the removed cobalt solution is less than lmg/1, short operation time,ivlow cost comparing with other methods such as chlorine, nickelic compound, zinc powder cementation, xanthate and naphthol, no another impurities, easily incorpora更多还原