高纯钴制备工艺研究

发布时间：2018-01-25 13:54

  本文关键词： 高纯钴 离子交换 树脂Monophos 杂质铁 电解精炼　出处：《河南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：高纯钴具有优良的半导体性质、磁性能及导电性能,是制备磁记录介质、磁记录磁头、光电器件、磁传感器和集成电路等元器件的重要材料。5N及以上纯度的高纯钴则主要用来制造超大规模集成电路行业用溅射靶材。目前限于技术原因,5N及以上高纯钴需要大量进口,因而开发具有自主知识产权的高纯钴制备技术尤为重要。本文通过离子交换提纯+CoSO4水溶液电解的方法制备高纯钴,并针对钴盐溶液中主要杂质元素Fe难以去除的共性问题,尝试采用新型螯合树脂Monophos吸附钴料液中的杂质元素Fe,并通过系统实验分析确定树脂Monophos吸附Fe的最佳工艺条件和CoSO4体系电解法制备高纯钴的稳定生产工艺。通过静态吸附试验,考察料液pH、脂液比、温度、接触时间对树脂吸附痕量Fe的影响。结果表明:螯合树脂Monophos对Fe有很强的吸附能力,在pH=3、温度30~60℃、脂液比1:5~1:8、吸附时间不低于90min条件下,硫酸钴料液中Fe去除率达70%,溶液中杂质Fe含量从约为2.0mg/L降到约为0.4mg/L。分别采用三种不同的酸HEDPA(一种有机膦酸)、HCl以及H2SO4对Monophos树脂进行动态解吸,结果表明,H2SO4对Monophos树脂不具备解吸能力,0.5mol/L的HEDPA解吸效果强于6mol/L的HCl。但是经过HEDPA解吸过树脂的再吸附能力不如盐酸。当采用HCl作为解吸液时,HCl的浓度直接影响到解吸的效果,当HCl浓度不低于5mol/L时解吸效果较好。洗脱再生后的树脂Monophos具有较好的重复使用性,再生能力较强,使用寿命长,是较为理想的吸附钴盐溶液中杂质Fe的离子交换树脂。通过对树脂Monophos吸附杂质Fe机理的探究发现:树脂中起主要吸附作用的官能团为磷酸基团,并通过红外光谱分析确定了P-O-H中的氢与金属离子发生了交换,使金属离子进入了树脂中与氧原子间通过离子键形式结合。对动力学吸附曲线的实验数据,分别采用拟一级动力学方程和拟二级动力学方程进行拟合,结果表明树脂Monophos吸附杂质Fe的过程符合拟二级动力学过程。控制机理的研究结果表明杂质Fe在树脂Monophos上吸附过程的控制步骤为颗粒扩散。分别采用Langmiur和Freundlich吸附等温模型对等温平衡吸附数据进行拟合,结果表明Langmiur方程能更准确地反映树脂Monophos对杂质Fe的吸附过程。吸附过程的热力学研究表明:杂质Fe在树脂Monophos上的吸附过程是自发的(△G0),吸热的(△H0),熵变为正(△S0)的过程,因此升高温度有利于吸附过程的进行。实验表明,硫酸钴体系下电解制备高纯钴的最佳工艺条件为:钴离子浓度60~70g/L;pH值为3~4;阴极的电流密度为100~300A/m2;电解温度为40℃~60℃。在该工艺条件制得的阴极钴片,经过GDMS分析,纯度达到了5N。
[Abstract]:High purity cobalt has excellent semiconductor properties, magnetic properties and conductive properties. It is used to prepare magnetic recording medium, magnetic recording head and optoelectronic device. High purity cobalt, which is an important material of magnetic sensors and integrated circuits, is mainly used to manufacture sputtering targets in VLSI industry. At present, it is limited to technical reasons. 5N and above high purity cobalt need to be imported in large quantities, so it is very important to develop high purity cobalt preparation technology with independent intellectual property rights. In this paper, high purity cobalt is prepared by ion exchange purification of CoSO4 aqueous solution electrolysis. Aiming at the common problem that the main impurity element Fe in cobalt salt solution is difficult to be removed, a new chelating resin Monophos is used to adsorb the impurity element Fe in cobalt solution. The optimum process conditions for adsorption of Fe by resin Monophos and the stable production process for preparation of high purity cobalt by electrolysis of CoSO4 system were determined by systematic experimental analysis. The static adsorption test was carried out. The effects of pH, ratio of lipids to liquid, temperature and contact time on the adsorption of trace Fe by chelating resin Monophos were investigated. The results showed that chelating resin Monophos had a strong adsorption ability on Fe in pH=3. The removal rate of Fe in cobalt sulfate solution was 70% when the temperature was 30 ~ 60 鈩，

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