Slag formation in the reduction zone using coke during high carbon ferromanganese production using South African manganese ores

It has been observed that during high carbon ferromanganese using South African ores, some practices do not find an easy answer from the theory and vice-versa. It has therefore become important to study under different reducing conditions what paths does the slag go through while forming during reduction in order to better understand its formation while higher manganese oxides are being reduced. The carbon monoxide gas amount and availability in a specific zone albeit its origin is influential and explanatory toward the degree of reduction and the formation of phases. The current investigation focused on the slag formation with the use of coke. The initial basicity of 1.25 was decreased by adding Silica to lower to a value of 1. The flux and the manganese ore were milled together for 15 minutes to homogenise the head sample and ensure same behaviour of the feed throughout. Graphite crucible was used in a alumina tube for experiments. Argon was blown in the furnace from room temperature to 600°C and switched off to allow carbon to start reducing the manganese ore until the set temperature was reached. The sample was kept for two hours at the set temperature, then the furnace was switched off. Argon gas was switched on from 600°C to room temperature. The temperatures used were 1200°C and 1350°C. XRF, XRD and SEM-EDS were used for characterization. Phases present in the slag that formed were therefore identified. A comparison was made between the slag quality obtained here and when only carbon monoxide was used for reduction means.