High Value Utilization of Modified Coal Gasification Slag as a Catalyst for Denitration

The modern coal chemical industry generates a large amount of coal gasification slag (CGS), which has an excellent activated carbon-based glassy aluminosilicate structure. But currently, it has not been processed well and utilized for high value. This article uses coal gasification slag as raw material and modifies it through acid treatment to produce a denitration catalyst. The effects of acid concentration, treatment time, and carbon content of the raw material on the catalyst's denitration activity are investigated. The catalyst's activity and stability were assessed by directly catalysing the decomposition of nitrogen oxides using experimental methods. The reasons for the increase in denitrification activity and the decomposition pathway of NO on coal gasification slag catalysts were revealed through characterization methods such as SEM, XPS, BET, MS, etc. It was found that the coal gasification slag treated with 3 mol·L-1 HAc had a NO removal rate of over 95 % at 500 °C. The characterization results indicate that acid treatment can etch the glassy spherical shell structure on the surface of coal gasification slag, resulting in more pore structures on the surface of the spherical shell and exposing internal active substances, mainly Fe2+, generating more oxygen vacancies and producing good medium temperature denitrification activity. The present study proposes a novel approach for the efficient utilization of coal gasification slag.