Abstract
The thermal NOx formed in sintering process has been calculated by a simulation model. The result shows that the amount of thermal NOx in waste gas was about 1/1000 of which from the actual sintering process. To assure of this result experimentally, the sintering test has been carried out exchanging the portion of nitrogen in air to argon, and it was confirmed that NOx in waste gas originated mainly from the nitrogen in coke. It was also proved that the nitrogen in ore was converted to NOx, however, the proportion of it was about 10% on total nitrogen in sinter mixture, so that the denitration of coke are necessary for the reduction of NOx from sinter plant.
For the purpose of denitration of coke, the high temperature reheating of coke was available and the ratio of denitration was increased with rising temperature. For example, the nitrogen in coke decreased from 0.9% to about 0.2% by a reheating at 1800°C for l hr. With sintering test using this low nitrogen coke, the amount of NOx formed could be diminished to about 30%.
