Study on hydrogen smelting reduction behaviour in synthetic molten HIsarna slag

Abstract

The reduction behaviour of hydrogen with FeO in synthetic molten HIsarna slag has been investigated using two experimental methods: (1) Blowing 5% or 10% H2-Ar onto the molten slag at 1450, 1475, 1550 ˚C respectively; and (2) Injecting 10% H2-Ar into the molten slag at the flowrates of 0.5, 1.0, 1.5 L/min. In the case of blowing the gas onto the melt, the reaction is controlled by gas phase diffusion in the initial stage and then liquid phase diffusion becomes dominant. The reaction rate is significantly improved by injecting the gas into the molten slag; bubbles are generated during the gas injection resulting in ample surface area between the gas and liquid slag. The overall reduction is controlled by the liquid phase mass transfer of FeO in the injection case; described by the penetration theory. Furthermore, an increased number of bubbles are generated with increasing flow rate, which in turn increases the reaction rate in the case of hydrogen injection