Reduction behavior of boron-bearing iron concentrates by bituminous coal and its magnetic separation

• Effects of temperature and time on the reduction behavior of boron-bearing iron concentrate briquettes were studied.
• Temperature played a crucial role in the selective reduction of iron minerals in boron-bearing iron concentrate briquettes.
• Boron is not volatile if the reduction temperature is controlled below 2609 K.
• Microstructure features of briquettes reduced at diverse temperatures and times are investigated.

In this study, the effects of temperature and time on the reduction behavior of boron-bearing iron concentrate briquettes were studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). Results indicated that reduction temperature played a crucial role in the selective reduction of iron minerals in boron-bearing iron concentrate briquettes with bituminous coal as a reducer. The increase in reduction time facilitated the generation of metallic iron and the grain growth of the metallic phase in the reduced briquettes, which had a beneficial effect on the separation of iron and boron in the subsequent low-intensity magnetic separation process. The magnetic material contained 92.81% Fe with a recovery of 95.58%, while in the boron-rich non-magnetic material, the grade and recovery values of B2O3 were 14.11% and 89.59%, respectively. In addition, the efficiency of extraction of boron of the non-magnetic material was 80.76%. The magnetic material and boron-rich non-magnetic material were good raw materials for steel-making and borax production.