Metallurgical Behavior and Microcrystalline Structure Transformation Mechanism of Coke in Hydrogen-rich Smelting Process

The present study aims to investigate the mechanisms of metallurgical behavior and microcrystalline structure transformation of coke in a hydrogen-rich smelting process, the co-gasification reaction of the coke with different H2O contents in the atmosphere from 0 to 20vol% was studied. The thermal properties of coke after the gasification reaction were studied by the coke reactivity index (CRI) and coke strength after reaction (CSR) at 1100℃. The microcrystalline structure was studied by Raman spectra, and the pore structure was studied by Scanning Electron Microscope (SEM), Brunner-Emmet-Teller (BET) and X-ray CT. The results indicate that the coke reactivity index increases with the increase of the H2O content, while the coke strength after reaction decreases. Erosion of the pores occurred at both the internal and surface parts of the coke gasified with pure CO2. However, as the H2O content increased up to 20%, the pores at the surface of the coke were eroded significantly. It was the pores enlarging, pore wall thinning and the generation of pore channels that eroded a large number of small pores inside the coke. This process consequently results in elevated levels of porosity within the coke. This indicates that the carbon dissolution of H2O within the coke is more pronounced, ultimately leading to a significant decrease in the strength of reduced coke. The results of Raman spectra demonstrated that the overall graphitization of the reduced coke increases with H2O content. This is due to the fact that H2O primarily erodes the irregular carbon structure, resulting in a relatively higher percentage of its internal regular structure.