The effect of petrographically determined parameters on carbonaceous reductant reactivity in production of high carbon ferromanganese

PREMA MSc STUDENT PRESENTATION
The effect of petrographically determined parameters on carbonaceous reductant reactivity in production of high carbon ferromanganese
30 September 2021 | Time: 10:00 – 11:00 (GMT+2 / CAT)
Presented by Sanda Soqinase, MSc (Eng) Metallurgical Engineering, University of Witwatersrand

In pyrometallurgical processes, the interaction between carbonaceous materials and molten slag is an important reaction based on carbothermic reduction. The extent of reduction of MnO (and SiO2 to a lesser extent) containing molten slag is influenced by the choice of carbonaceous reductant. Therefore, proper selection of the carbonaceous reductant and a relevant method to assess the potential for carbonaceous reductants to reduce slags is important. For this study, two medium-rank C bituminous coals (coal 1 and coal 2) and anthracite were investigated. The study aimed to investigate the effect of petrographic characteristics on carbonaceous reductant reactivity towards slag.

To assess the potential of carbonaceous materials to react with slag, the reductant reactivity towards slag tests were conducted in a gas-tight muffle furnace at 1500°C at fixed intervals of 72 minutes, 144 minutes, 216 minutes, 288 minutes, and 360 minutes reaction time. The reductant reactivity towards slag was determined by studying the generated mass loss rates indicated by mass loss curves, reporting mass loss as a function of reaction time and temperature. From the results, coal 2 reported a higher overall mass and anthracite with the least mass loss. The influence of organic constituents and their influence on reactivity is important in order to understand the effectiveness of a reductant and the transition effect upon heating which ultimately control the properties of coal. The petrographic analyses results in terms of maceral analysis showed coal 2 to consist of the highest proportion of reactive macerals followed by coal 1 and anthracite comprising of the highest inert macerals. The proportions of macerals behave differently when heated and influence the overall behaviour of coal. Coal 2 comprising of the highest reactive macerals was found to be the most reactive through the reductant reactivity tests whilst anthracite with the highest inert maceral proportions was found to be the least reactive carbonaceous reductant.