Phase relations in the reduction zone in presence of carbon monoxide during high carbon ferromanganese production using south African manganese ores

During High Carbon Ferromanganese production as well as other reduction processes, the chemical composition of the feed plays a crucial role on the quality of the products. It is believed that the reduction from high manganese oxides to their lower oxides during HCFeMn production, the transitional phases that form in the prereduction zone and reduction zone are very influential on the coke-bed zone behavior. Data on acidic manganese ores use are available. However, on the basic manganese ores especially the South African ores data remain very challenging. The current study investigates the phases that have formed in the reduction zone before reaching the coke-bed zone using basic South African ores. The basicity has been reduced from 1.25 down to 1 with the addition of silica. Graphite crucible placed in a alumina tube furnace; was used for the experiments. The ore and flux were milled together for 15 minutes to enhance the homogeneity of the feed. Argon was blown in the furnace from room temperature to 600°C and carbon monoxide thereafter until the set temperature was reached. The samples were kept at the set temperature for two hours and the furnace was switched off while carbon monoxide continued to be blown in until 600°C and the switched back to argon up to room temperature. Both argon and carbon monoxide were blown in at 0.4L/min. The temperature varied from 1300°C to 1350°C. The characterization of the feed and products have been conducted using XRF, XRD and SEM-EDS. Different phases were identified in the reduction zone and compared to the prereduction zone.