CO Reactivity and Porosity of Manganese Materials

Abstract

In the production of manganese alloys there is a continuing effort to utilize all raw materials. As ore fines cannot be directly added to the furnace, the fines must be agglomerated to sinter, pellets or briquettes. However, as the materials changes properties during agglomeration, there is a need to know how the effect the agglomerated material affects the furnace performance, compared to lumpy material. In this paper the CO reactivity and porosity of 3 ores and their agglomerates of sinter and pellets is studied.In the furnaces, the higher manganese oxides (MnO2, Mn2O3, Mn3O4) are reduced to MnO with CO gas, producing CO2. If the CO reactivity is low, the CO2 may be produced above 800°C triggering the Boudouard reaction, which increases the total carbon and energy consumption. Hence, a high CO reactivity is beneficial for the process.The present work combines the study of CO reactivity and porosity of eight different manganese materials. It is shown that manganese materials with high initial porosity have high CO reactivity. This means that Gabonese ore and CVRD ore will have a higher CO reactivity compared to their sinter and pellets. For Assmang ore, which has a low initial porosity, making an agglomerate with higher porosity, will increase the CO reactivity. The additional carbon consumption per ton of produced metal was also calculated for the materials investigated.