工业纯铁电解制备高纯铁

Preparation of high purity iron by industrial pure iron electrolysis

以工业纯铁为原料,运用正交设计对电解制备高纯铁的影响因素进行研究,以电沉积速率、电流效率、电解铁纯度及外观为指标,确定各因素的显著性及最佳组合方案。用ICP-AES、扫描电镜(SEM)对电解铁纯度及其主要杂质元素进行分析,通过退火还原对杂质氧进行分析提纯,并采用NaoH溶液浸出电解铁片,测量浸出液中SO_4^(2-)浓度。结果表明:溶液Fe^(2+)浓度50g/L,pH值为4,电解温度25℃,电流密度100A/m^2,是电解制纯铁实验的最佳因素组合。在该工艺参数下,电沉积速率为0.549g/h,电流效率达到89.2%,电解铁纯度达到99.98%以上;电解铁退火还原后氧元素含量大大减少,浸出液中硫酸根的量大约为30mg/L,且结合实际电解条件可知,氧和硫的主要存在形式为铁的氧化物和硫酸亚铁。

Pure iron is used as raw material to analyze the influencing factors of electrolytic iron through orthogonal design. Electro-deposition rate, current efficiency, purity and appearance of the electrolytic iron are taken as the indexes to find out the conspicuousness of each factor and their optimal combination scheme. The purity of electrolytic iron and its main impurities are analyzed by ICP-AES and SEM, and the impurity oxygen is also analyzed and purified through annealing reduction. Besides, the electrolytic iron is separated by using NaOH solution, and the concentration of SO42-is analyzed through ICP-AES. The results show the best combination of electrolysis iron test program is that the concentration of Fe^2＋solution is 50 g/L, the pH value is 4, the temperature is 25℃ as well as the current density is 100 A/m^2. Under the optimal conditions, the electro-deposition rate is 0.549 g/h, the current efficiency is 89.2%, and the purity of electrolytic iron is over 99.98%. After annealing, oxygen content is greatly reduced and the amount of sulfate in the leachate is about 30 mg/L. From actual electrolysis conditions, it can be found that the main forms of oxygen and sulfur are iron oxides and ferrous sulfate.