Thermodynamic Simulation and Transformation Behaviours of Lead during Iron Ore Sintering

Abstract

Lead (Pb) increases the corrosion rate of refractory lining in blast furnaces. The iron ore sintering process plays a vital role in decreasing lead content of the feeding materials for blast furnaces. In this paper, lead compounds in the raw materials blend and the sinter product were leached out sequentially and classified into four categories. In the raw materials blend, PbS accounted for about 66.25% of lead compounds and 23.57% of lead was found as PbO. While in the sinter product, the main lead compounds were PbSO₄, PbO·Fe₂O₃ and PbO. The transformation and removal behaviours of lead compounds were simulated via Factsage7.1 and tube furnace tests. It was confirmed Pb could be removed in forms of PbCl₂, metallic Pb and PbO during iron ore sintering process. The lead removal rate in the industry was 49.77%. While, with the increasing carbon to 15%, over 93% of the lead was removed in lab. In addition, increasing the maximum sintering temperature and CaO content properly could also enhance the removal of lead.

Transformation and removal behaviours of lead in four layers of the sintering process.