Extracting indium and preparing ferric oxide for soft magnetic ferrite materials from zinc calcine reduction lixivium

• Published in: Journal of Central South University of Technology. Science & technology of mining and metallurgy 2011-08, Vol.18 (4), p.1074-1079
• Main Authors: He, Jing, Tang, Mo-tang, Zhou, Cun, Wu, Sheng-nan, Chen, Yong-ming, Wang, Tao, Huang, Ling
• Format: Article
• Language: English
• Subjects: Engineering; Metallic Materials
• ISSN: 1005-9784; 1993-0666
• DOI: 10.1007/s11771-011-0806-3

A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution, copper and indium were firstly recovered by iron powder cementation and neutralization. The recovery ratios of Cu and In are 99% and 95%, respectively. Some harmful impurities that have negative influences on magnetic properties of soft magnetic ferrite material are deeply removed with sulfidization purification and neutral flocculation method. Under the optimum conditions, the content of impurities like Cu, Pb, As, Al in pure Zn-Fe sulfate solution are less than 0.004 g/L, but those of Cd, Si, Ca and Mg are relatively high. Finally, thermal precipitation of iron is carried out at 210 °C for 1.5 h. The precipitation ratio of Fe is 93.33%. Compared with the quality standard of ferric oxide for soft magnetic ferrite materials, the contents of Al and Mg in obtained ferric oxide powder meet the requirement of YHT1 level of ferric oxide, and those of Si, Ca meet the requirement of YHT3 level of ferric oxide. XRD and SEM characterizations confirm that the obtained sample is well-dispersed spindle spherule with regular α -Fe 2 O 3 crystal structure. The length-to-diameter ratio of α -Fe 2 O 3 powder is (3–4):1 with an average particle size of 0.5 μm.