Pilot-scale extraction of iron from flotation tailings via suspension magnetization roasting in a mixture of CO and H2 followed by magnetic separation

Iron tailings is the most common and largest mining waste, and given the serious social, economic, and environmental impacts caused by tailings, green and safe technologies are urgently needed for the efficient treatment of tailings. In the present work, efficient extraction of iron from flotation tailings via the suspension magnetization roasting and magnetic separation has been demonstrated as a promising way to reduce emissions and extracting iron from flotation tailings. The possibility of iron extraction from flotation tailing containing 21.86% iron and transformation mechanism were studied in a pilot-scale experiment. The results revealed that an iron concentrate having an iron grade of 66.51% and iron recovery of 72.90% could be obtained under the following conditions: roasting temperature of 470 degrees C, reductant concentration of 30%, reductant ratio of 1:1 (CO: H-2), and total gas flow of 16.0 m(3)/h. The mineralography and magnetic performance of the preconcentration concentrate, roasted product, magnetic concentrate, and magnetic tailings were studied by X-ray diffraction, iron chemical phase analysis, and the vibrating sample magnetometer. The effect of roasting on the microstructure of the products was also analyzed by scanning electron microscopy and laser particle size analysis to help understand the mechanism.

Automated summary

The study demonstrates that the efficient extraction of iron from flotation tailings through suspension magnetization roasting and magnetic separation is a promising way to reduce emissions and efficiently treat mining tailings.