Developed model for reduction mechanism of iron ore pellets under load

Abstract

A laboratory scale shaft furnace for testing the reduction of commercial iron ore pellets under load was constructed. A series of reduction experiments of iron ore pellets with a synthetic reformed natural gas was carried out under various operational conditions of varying temperature, type of ore pellets and applied load. The reduction tests were carried out at 750–1000°C under different loads, i.e. 0·2, 0·4 and 0·57 kg cm⁻². The sticking phenomenon accompanying reduction of iron ore pellets under load was investigated and was found to be dependent on temperature, chemical composition and applied load. The experimental results were analysed to investigate the reduction kinetics and mechanism of iron ore pellets under controlled conditions of temperature and applied load. A model was developed depending on the shrinking core modulus and mixed control ratio to give a definite and quantified measure of reduction reaction. This model allows good analysis of the actual effect of reduction temperature and applied load upon controlling mechanism and furthermore, it indicates the relative effect of the different mechanisms in the mixed control regime.

Keywords:

• Iron ore pellets
• Shaft furnace
• Direct reduction
• Kinetics and mechanism
• Sticking
• Reduction under load