Optimizing iron separation and recycling from iron tailings: A synergistic approach combining reduction roasting and alkaline leaching

Abstract

Iron tailings, a type of refractory iron ores, pose a challenge for effective iron recovery due to the complex mineral combinations and liberation modes. In this study, we proposed a new approach to improve the quality of iron concentrates by combining alkaline leaching with magnetization roasting-magnetic separation, which promoted the leaching of silica and aluminum minerals from iron tailings. We investigated the leaching process conditions, phase transitions, and microstructure evolution of joint magnetization roasted iron tailings in the presence of an alkaline solution. Our research findings showed that with optimal leaching conditions, the iron concentrate from magnetic separation was improved from 59.97 % to 65.07 % in iron grade while maintaining an iron recovery of 92.05 %. The heat and mineral phase transformation during magnetization roasting destroyed the structure of iron tailings particles, resulting in the formation of pores and microcracks that weakened inter-mineral bonding. Additionally, alkaline leaching facilitated the extraction of Si and Al from the structure-damaged iron tailings particles, eliminating 83.75 % of Si minerals and 68.73 % of Al minerals. This study offers a promising solution for iron recovery from refractory iron ores, reduces environmental pollution from tailings, and could enhance current iron recovery technology.