NO_x and SO₂ formation in the sintering process and influence of sintering material composition on NO_x emissions

NO_x and SO₂ formation in the sintering process and the influence of coke powder content, moisture content and adding additives on NO_x emissions were investigated by the sintering pot experimental method. The results showed that the combustion zone moved downward along the sintering pot after the sintering started. The NO_x concentrations of all monitoring points below the combustion zone were basically the same. SO₂ generated in the combustion zone was adsorbed and accumulated in the sintering materials below the zone. Then, SO₂ was released by pyrolysis, and finally discharged from the outlet of sintering pot. So the significant SO₂ couldn't be detected before the burning through point, and the relationship between the SO₂ concentration and the sintering time displayed an inverted "V" curve. NO_x produced from the sintering process was mainly thermal-NO_x, and most of it was NO, the NO₂ concentration was very low. Reducing the coke powder and moisture contents, or adding sintering additives could effectively reduce NO_x emissions.