Enhanced Removal of Potassium, Sodium, and Lead During the Iron Ore Sintering Process

In this study, a mixture rich in K, Na, and Pb, composed of undesired elements rich iron ore A, sinter dust, and blast furnace dust (ore-dust mix,), is sintered along with the regular iron ore. The K, Na, and Pb compounds within the ore-dust mix are identified as alkali chlorides, alkali aluminosilicates, PbO, and PbSO₄ using X-ray diffraction. The primary objective is to investigate the impact of three distinct sintering technologies: regular (pre-reduction) sintering, double-layer sintering, and hearth-layer sintering, on the removal degrees of K, Na, and Pb. In both the regular and double-layer sintering processes, the K, Na, and Pb contents within the blend of raw materials was measured approximately 0.430 wt%, 0.105 wt%, and 0.033 wt%, respectively. Moreover, the ratio of ore-dust mix to the regular ore was 0.54. In the regular sinter pot test, sinter feed was uniformly placed in the pot. In the run of the regular sinter pot test with the optimal coke breeze ratio of 20 wt%, the removal degrees of K, Na, and Pb were 79.5%, 67.5% and 92.7%, respectively. In comparison, the double-layer sintering technology resulted in a slight increase in the removal degrees for alkali metals and a similar removal degree for Pb, while utilizing a reduced coke breeze ratio of only 8.10 wt%. The removal mechanism of the hearth-layer and double-layer sintering processes are similar. However, the coke breeze ratio decreases to 6.63 wt% as the fraction of ore-dust mix within the blend of raw materials is reduced to 7 wt% during the hearth-layer sintering process.

Graphical Abstract