Preliminary study on the phase relation in the coke-bed zone (Basic South African ore)

Investigations on coke-bed relations with acidic manganese ores have been reported number of times. The correlation between the mineralogy, property, reactivity of the ore and the products during the production of high carbon ferromanganese have been reported. A theoretical study has proven that the energy consumption of different basic South African manganese ores were very dependent on the chemical composition of the feed. This has a direct impact on the phases that form in the prereduction, reduction and consequently the coke-bed zone. In the present study high grade manganese ore was subjected to the reduction in presence of coke and subsequent phases formed identified. The temperature range investigated was 1400°C, 1450°C, 1470°C and 1485°C. Al2O3 and SiO2 were used as fluxes to adjust the basicity from 1.25 down to 1. The ore and fluxes were mixed and milled together for 15 minutes to obtain a homogeneous feed. A alumina vertical tube furnace was used for the experiments. The head sample and products were characterized using XRF, XRD and SEM/EDS to identify phases that formed in the coke-bed. Preliminary results showed poor immiscibility between metal and slag for all temperatures, but at 1400°C the separation was much better compare to the other temperatures. Results reveal that at 1400°C, in the metallic phase 71.8% and 16.8% of Mn and Fe respectively whereas in the slag 25.56%, 0.6377%, 50.93% and 1.24% of CaO, MgO, MnO and FeO respectively.