Preparation of high purity iron by industrial pure iron electrolysis

Abstract

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 Fe2+solution is 50 g/L, the pH value is 4, the temperature is 25 ℃ as well as the current density is 100 A/m2. 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.