Assessment on the effect of unburned pulverized coal on the properties of coke in blast furnace

Abstract

The influence of anthracite unburned pulverized coal (AUPC) on the properties of coke at high temperature was studied using the thermogravimetric equipment. The micro morphology and mineral transformation were analyzed by scanning electron microscope with energy spectrum (SEM-EDS) and X-Ray diffracton (XRD) in present research. The results show that CO2 preferentially reacts with AUPC, making SiC easier to form and wet the slag, which can enter pores and passivate gas from entering. Meanwhile, AUPC ash generates chemical reaction with coke ash to form yoshiokaite and calcium iron oxide that has a lower melting point than mullite and decrease the viscosity of ash slag, allowing SiO2 to diffuse quicker to the coke surface and react to SiC, enabling quicker wetting. Besides, CaO may also catalyse gasification reactions. The ash wetting and catalysis of iron or CaO might shift inner-pore gasification to the outside and delaying the degradation of coke.