Abstract
Abstract : This work presents results of a study conducted on the carbothermic reduction of two different manganese ores, namely, Assmang ore which is a basic manganese ore and Comilog ore which is an acidic manganese ore. This research mainly aimed at the study of the reduction rate of MnO from two different manganese ores during the ferromanganese (FeMn) production process. The emphasis was on how different charge compositions affect the reduction rate of MnO by solid carbon. The experimental work was carried out in a thermogravimetric furnace using Polish metallurgical coke as reducing agent in the presence of CO at atmospheric pressure. Charge composition and temperature were used as experimental variables in this investigation. The composition was varied by adding lime or quartz depending on whether it is Comilog or Assmang ore respectively from 0.04 to 1.0 and from 1.3 to 0.5. XRF and EPMA were performed on slags to quantify the extent of reduction and the dissolution of the fluxing agents respectively. XRF results for experiments at 1400°C were very different from what was expected since the metal and the slag as well as some carbon were strongly mixed which led us to discard them and consider only those at 1500°C. It has been found that temperature had a strong effect on the reduction rate of MnO. The rate was substantially increased in the temperature range of 1400-1500°C for Assmang charges by almost two times of the original rate (at 1400°C) while for Comilog charges, the reduction rate increased for almost three times whereas on the other hand, basicity seemed to merely have a slight effect on the reduction rate. The calculated activation energies were estimated to be in the range of 203 to 350 kJ/mol for Assmang charges and from 357 to 525kJ/mol for Comilog charges.
M.Tech. (Extraction Metallurgy)