High-Efficiency Iron Extraction from Low-Grade Siderite via a Conveyor Bed Magnetization Roasting-Magnetic Separation Process: Kinetics Research and Applications

Upgrading and utilizing low-grade iron ore is of great practical importance to improve the strategic security of the iron ore resource supply. In this study, a thermal analysis-infrared (IR) analysis-in-situ IR method was used to investigate the reaction mechanism and kinetics of Daxigou siderite. Experiments were conducted using a conveyor bed magnetization roasting process (CBMRP) to investigate the magnetization of siderite. Multi-stage magnetic separation processes were adopted to extract magnetite. The results show that simultaneously the iron carbonate in siderite decomposes, and magnetite is formed between 364 degrees C and 590 degrees C under both inert and reducing atmospheres. The activation energy of the magnetization roasting reaction is 106.1 kJ/mol, consistent with a random nucleation and growth reaction mechanism. Magnetization roasting at 750-780 degrees C for approximately 3.5 s in the CBMRP results in a magnetic conversion rate of >0.99 of the iron minerals in the siderite. A beneficiation process of one roughing, one sweeping, and three cleaning processes was adopted. A dissociation particle size of -400 mesh accounting for 94.78%, a concentrate iron grade of 62.8 wt.%, and a recovery of 68.83% can be obtained. Overall, a theoretical and experimental basis is presented for the comprehensive utilization of low-grade siderite.

Automated summary

Upgrading and utilizing low-grade iron ore is important for improving iron ore resource supply security. This study investigated the reaction mechanism and kinetics of Daxigou siderite using a thermal analysis-infrared analysis-in-situ IR method. The results show that magnetite can be formed by decomposing iron carbonate in siderite under certain conditions. Magnetization roasting at specific temperatures and time can achieve high magnetic conversion rate of the iron minerals in the siderite. A beneficiation process was adopted to obtain high-grade concentrate.