Coal pyrite microwave magnetic strengthening and electromagnetic response in magnetic separation desulfurization process

Abstract

Coal desulfurization is imperative to creating clean coal and reducing harmful emissions during the burning process. Due to the lack of effective technology in the field of fine coal dry separation, a novel microwave-enhanced magnetic property processing method was demonstrated in this manuscript. Using representative simulated minerals, the response and absorption characteristics of coal pyrite were intuitively demonstrated while analyzing the selective absorption mechanisms of different minerals in fine coal. Results show that the coal pyrites from Inner Mongolia were reduced by approximately 20% after 60 s of microwave treatment, and 60% after 90 s. The binding energy and chemical shift were quite large when the oxidation state was high. Fe^2 + and troilite FeS were oxidized to Fe₂O₃ after 60 s microwave treatment, and to Fe^3 + after 90 s. Dynamic equilibrium was reached after 3 min of microwave treatment. The conversion rate was lower for pyrite to pyrrhotite than for pyrrhotite to troilite. The conversion of pyrrhotite to troilite appeared to be sensitive to the amount of microwave treatment. The specific susceptibility dropped rapidly and was nearly an order of magnitude greater than the raw coal. This study indicates a high possibility for coal desulfurization through this dry method enhanced with microwave energy.