Study on the Conversion Mechanism of Iron- Containing Coal Gasification Slag to No in High Temperature Flue Gas of Cement Kiln

Nitrogen oxide is an important air pollutant that can cause serious harm to the body and also has a damaging effect on the ozone layer. Aiming at the large amount of NO emitted in the flue gas of cement kilns, non-ammonia catalytic materials have a simple process and do not produce secondary pollution, and are considered to be an ideal conversion method for NO. In this paper, the denitrification performance of coal gasification slag used as denitrification material in cement kiln flue gas was investigated at different temperatures and oxygen concentrations. The transformation mechanism of NO was investigated by analyzing the changes of surface element valence state before and after denitrification, the adsorption and desorption of NO and the formation of intermediate in the heating process. The results show that the conversion rate of NO in flue gas can reach 83.491% when the temperature is 1000℃ and the oxygen concentration is 1%. The charged ionic groups generated by the isomorphous substitution of Fe3+ in coal gasification slag play an important role in the decomposition of NO as active components. It can not only increase the number of surface oxygen vacancies, but also catalyze the fracture of N-O as an active component; at the same time, Fe3+ combines with O- and NO- generated by N-O fracture to form Fe3+-O- and Fe3+-NO-, which can be decomposed into Fe2+, N2 and O2 at high temperature.