The Effect of Electrolytic Temperature on the Purity of Electrolytic Pure Iron

The influence of electrolytic temperature on the purity grade of electrolytic pure iron, variations in elemental content, macroscopic morphology, and microstructural characteristics was studied using electrodeposition experiments alongside glow discharge mass spectrometry and scanning electron microscopy. As electrolyte temperature increased, the total impurity content in electrolytic pure iron decreased; the iron reached a purity level of 4N1 (99.991%) when electrolyzed at 75 °C. The content of gaseous elements also decreased with increasing temperature, with a total content of only 46.07 ppm during electrolysis at 75 °C. Among the major metallic elements, the Ni content was minimally affected by temperature, while the concentrations of other metallic elements were at their lowest during electrolysis at 75 °C, remaining below 0.5 ppm, except for elements such as Co, Cu, Ni, and Zn. With an increase in the electrolyte temperature, the macroscopic morphology evolved into a smooth, silver-white surface. The microstructure on the surface evolved into an irregular polygonal nucleus structure, and the microstructure on the cross-section exhibited a striped characteristic. Therefore, electrolytic pure iron with a purity exceeding 4N, exhibiting both excellent macroscopic and compact structures, can be prepared at an electrolytic temperature of 75 °C.