Sintering behaviours of iron ore with flue gas circulation

Abstract

Flue gas circulation is an important method for energy conservation and pollutant emission reduction in iron ore sintering. In this paper the effects of flue gas recirculation ratio on sintering of different iron ores including haematite, magnetite and limonite were studied by illustrating the variation of sinter bed temperature, atmosphere and mineralisation characteristics of different types of iron ores induced by the circulation. It shows that the proper flue gas circulation ratios for haematite, magnetite and limonite are 37, 30 and 25%, respectively. For magnetite ore, preheating and high consumption of oxygen in combustion zone caused more silicate minerals and less acicular calcium ferrite, thereby lowering sinter tumbler strength. As for haematite ore, the rapid change of temperatures of combustion, melting and solidification zones leads to elevated combustion efficiency and increased formation of acicular calcium ferrite, which enhances the sinter strength. When using limonite ore as the main raw material, high oxygen consumption, lower maximum temperature of sintering bed, higher cooling rate and larger porosity of sinter are observed.

Iron Ore Sinter Macro- and Micro-Structures, and Their Relationships to Breakage Characteristics

“…The effects of sintering temperature, residence time at high temperature and sintering atmosphere on sinter properties have been investigated in many previous studies [33][34][35][36][37]. The present study focuses on the details of conditions in terms of temperatures, compositions and atmospheres potentially affecting sinter properties through (a) the identifications of the breakage surfaces of industrial iron ore sinter product and returns, (b) understanding of the sinter microstructures and (c) relating those to phase equilibria information.…”

“…This weak structure is exemplified by Type II microstructures, formed by reoxidation of the sinter surface on solidification. The reported increase in sinter performance by flue gas recirculation, a practice that lowers the oxygen concentration in the gas flow during the solidification of the sinter [36,37], may result in reduction in the extent of sinter reoxidation, and of the formation of the weaker Type II microstructure, and therefore reduced generation of sinter fines.…”

Flue Gas Circulating Sintering Based on Biomass Fuel on Reduction of NO_x and SO₂ Emission

“…Chen X.L. et al 13) studied the effects of flue gas recirculation ratio on sintering of different iron ores including haematite, magnetite and limonite. Gan M. et al 14,15) studied on iron ore sintering process of flue gas recirculation together with using biochar as fuel, and the results show that the proper proportion of biomass replacing coke breeze had little hardness to the productivity and the quality of sinter, meanwhile, which could alleviate fossil fuel crisis and realize the comprehensive utilization of energy.…”