Effect of temperature on suspension magnetization roasting of hematite using biomass waste as reductant: A perspective of gas evolution

Abstract

The magnetization reduction of hematite using biomass waste can effectively utilize waste and reduce CO₂ emission to achieve the goals of carbon peaking and carbon neutrality. The effects of temperatures on suspension magnetization roasting of hematite using biomass waste for evolved gases have been investigated using TG-FTIR, Py-GC/MS and gas composition analyzer. The mixture reduction process is divided into four stages. In the temperature range of 200–450 °C for mixture, the release of CO₂, acids, and ketones is dominated in gases products. The yield and concentration of small molecules reducing gases increase when the temperature increases from 450 to 900 °C. At 700 °C, the volume concentrations of CO, H₂ and CH₄ peak at 8.91%, 8.90% and 4.91%, respectively. During the suspension magnetization roasting process, an optimal iron concentrate with an iron grade of 70.86%, a recovery of 98.66% and a magnetic conversion of 45.70% is obtained at 700 °. Therefore, the magnetization reduction could react greatly in the temperature range of 600 to 700 °C owing to the suitable reducing gases. This study shows a detail gaseous evolution of roasting temperature and provides a new insight for studying the reduction process of hematite using biomass waste.