Prospects of green extraction of iron from waste dumped flotation tailings by H2: A pilot case study. (1st January 2022)

• Record Type: Journal Article
• Authors: Tang, Zhidong; Zhang, Qi; Sun, Yongsheng; Gao, Peng; Han, Yuexin
• Is Part Of: Journal of cleaner production. Volume 330(2022)
• Publication Date: 2022-01-01
• Subjects: Flotation tailing -- Hydrogen-based suspension magnetization roasting -- Green extraction -- Phase transformation -- Magnetic performance -- Microstructure; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2021.129853
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Flotation tailings are a secondary iron ore resource with abundant reserves and recycling value. In this study, low-grade flotation tailings (TFe = 21.86%) with silica of 57.85% has been studied by the hydrogen-based suspension magnetization roasting (HSMR) and magnetic separation varying the roasting temperature, reductant concentrate, total gas flow, and feeding rate to evaluate their effect on iron grade and iron recovery in magnetic concentrate. According to the pilot case study, the best iron concentrate (Fe grade of 66.65% and recovery of 80.11%) was obtained at a temperature of 500 °C, H2 concentration of 14.4%, the total gas flow of 18.0 m 3 /h, and feeding rate of 100 kg/h. After HSMR, the phase transformation results indicated that the weakly magnetic of hematite in flotation tailings were transform to the stronger magnetic magnetite, and the iron in magnetite increased from 17.57% in flotation tailings to 97.73% in magnetic concentrate. Microstructure analysis is presented which shows that the HSMR process destroys the structure of the iron minerals particles, making them form more pores and microcracks, which greatly reduces the structural strength of the particles and helps to reduce the energy consumption of the grinding operation. This study provides a pilot case of HSMR for the green and low-carbon development of the iron and steel industry. Graphical abstract: Image 1 Highlights: Hydrogen-based SMR technique of flotation tailings was investigated. Roasting temperature has the greatest effect on the separation index of product. Iron concentrate with Fe grade of 66.65% and Fe recovery of 80.11% was obtained. HSMR destroys the structure of particle, which facilitates grinding operations. HSMR provides a greener method for resource utilization of flotation tailings.