Preparation of Red Iron by Magnetization Roasting-Hydrothermal Method Using Ultra-Low-Grade Limonite

Iron is one of the most important strategic materials in national production, and demand for iron ore huge world. High quality reserves have been almost exhausted, it necessary to develop a technology that utilizes low-grade ore. Limonite representative due its complex mineral elemental composition. In this paper, union process was employed separate elements limonite. Firstly, rough concentrate obtained under 1.0 T magnetic field intensity −0.074 mm > 94.84% grinding fineness; then, magnetization roasted temperature 700 °C, 60 min retention time, 3 wt% biochar consumption, 0.15 intensity. The grade 59.57% recovery 90.72%. Finally, red pigment produced via high hydrothermal method order increase additional value ultra-low-grade optimal parameters were 10.0 g/L solution acidity, 200 °C reaction temperature, 5 h 6:1 solid-to-liquid ratio. mechanism also discussed.