Factors Accelerating Dioxin Emission from Iron Ore Sintering Machines

Abstract

Causal factors for dioxin (D) emission from iron ore sintering machines has been investigated by means of pot tests designed with the two-level seven-factor orthogonal array (L₈(2⁷)) and multiple regression analysis on commercial plant data.
EP dust, BF dust and purchased scale were major D-accelerators; quick lime was a D-suppressor. D emission was not a sum but a product event of those factors, and their coefficients were 28, 4, 4 and 0.7 times for 5% EP dust, 5% BF dust, 5% purchased scale and 2% quick lime additions, respectively. As for operational conditions, bed height, coke content, gas velocity and after burning had insignificant effects whereas the increase of hearth layer and the decrease of BTP position increased D emission, which implied the hearth layer and wind boxes could be other synthesis sites.