A novel ironmaking technology is under development at the University of Utah. This technology produces iron directly from fine iron oxide concentrate by a gas-solid suspension reduction, utilising hydrogen as the main reducing agent for high reactivity, for the elimination of carbon dioxide release during ironmaking operations and also pursuing the direct use of concentrates to bypass the problematic pelletisation/sintering and cokemaking steps in the steel industry. This paper is mainly focused on the kinetic feasibility tests of the proposed process showing that the reduction rate was fast enough to obtain 90-99% reduction within 1-7 s at 1200-1500uC, depending on the amount of excess hydrogen supplied with the iron oxide. This indicates that the reduction rate of concentrate particles by hydrogen containing gases is sufficiently fast for a suspension reduction process and forms the most important basis for the new technology.

A new process for converting sulfur dioxide to elemental sulfur by reaction cycles involving calcium sulfide and calcium sulfate without generating secondary pollutants was developed at the University of Utah. In this process, sulfur dioxide is reacted with calcium sulfide to produce elemental sulfur and calcium sulfate. The latter is reduced by hydrogen to regenerate calcium sulfide. In the present work, the effects of different pelletization conditions for the initial reactant calcium sulfate on the strength and reactivity of the pellets were determined. These pelletization conditions included the type, amount, and impregnation method of catalyst, the binder amount, and sintering. The pellets with the best properties were then reduced with hydrogen in the temperature range 973 to 1173 K, while measuring the kinetics, over several cycles of the two-step process. Nickel-catalyzed and fired pellets produced by the use of molasses or cement as a binder showed the highest compressive strength as well as good reactivity during the cyclic tests. The binder amount did not significantly affect the reaction rate.

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A new process for converting sulfur dioxide to elemental sulfur by a cyclic process involving calcium sulfide and calcium sulfate without generating secondary pollutants, developed at the University of Utah, was described in Part I of this series. In this process, sulfur dioxide is reacted with calcium sulfide to produce elemental sulfur and calcium sulfate; the latter is reduced by hydrogen to regenerate calcium sulfide. Here, in Part II, the effects of different pelletization conditions for the initial reactant calcium sulfate on the reactivity of CaS pellets produced from calcium sulfate pellets toward sulfur dioxide were studied. Experiments were performed to investigate the effects of temperature in the range 1023–1173 K, pellet size, cycle repetition, and water vapor or carbon dioxide content in the sulfur dioxide stream. The binder amount and the presence of nickel catalyst did not significantly affect the reaction rate.

A new process for converting sulphur dioxide to elemental sulphur by a cyclic process involving calcium sulphide and calcium sulphate without generating secondary pollutants was developed at the University of Utah. In this process, sulphur dioxide is reacted with calcium sulphide to produce elemental sulphur and calcium sulphate. The latter is reduced by hydrogen to regenerate calcium sulphide. In the present work, the effects of different pelletisation conditions for the initial reactant calcium sulphate on the strength and reactivity of CaSO 4 pellets and on the reactivity of CaS pellets produced from CaSO 4 pellets toward sulphur dioxide were determined. These pelletisation conditions included the type, amount and impregnation method of catalyst, the binder amount and sintering. The pellets with the best properties were then utilised for kinetics measurements over several cycles of the two step process in the temperature range of 973-1173 K. Nickel catalysed and fired pellets produced by the use of molasses or cement as a binder showed the highest compressive strength as well as good reactivity during the cyclic tests. The binder amount did not significantly affect the reaction rate.