Utilization of Waste Straw Biomass in Suspension Magnetization Roasting of Refractory Iron Ore: Iron Recovery, Gas Analysis and Roasted Product Characterization

The straw-type biomass, as a green and alternative reductant for the suspension magnetization roasting (SMR) of iron ores, is proposed. The roasted products are investigated at a roasting temperature of 750 degrees C, the roasting time of 7.5 min and the biomass dose of 25%. The iron phase results indicate that hematite ores were reduced to magnetite by the biomass, and the magnetization transformation increased from 0.64 A center dot m2 center dot g-1 to 36.93 A center dot m2 center dot g-1. The iron ore microstructure evolutions of holes and fissures are detected by SEM-EDS. The biomass pyrolyzed to form CO2, CO, CH4, H2O, H2, C=O, benzene skeleton, C-Hand C-O compounds at 200-450 degrees C, while the mass loss of the magnetization roasting process occurred at 450-750 degrees C by using TG-FTIR. The GC/MS results showed that the organic gases preferred to produce the O-heterocycles at 329 degrees C while the hydrocarbons were dominant at the high temperature of 820 degrees C for the hematite ore and biomass mixture. The gas composition analysis explained that the reducing gaseous products (CO, CH4 and H2) were used as a reductant and consumed obviously by hematite ore in the SMR process. The innovative utilization of biomass waste was effective for iron recovery of hematite ore and contributes to the reduction of greenhouse gases and the protection of the environment.

Automated summary

This research proposes the use of straw-type biomass as a green and alternative reductant for the suspension magnetization roasting of iron ores. The results show that the biomass effectively reduces hematite ores to magnetite, leading to a significant increase in magnetization transformation. The study also investigates the microstructure evolution and thermal decomposition behavior of the iron ore, as well as the composition of organic gases produced during the process.