Pre-reduction of United Manganese of Kalahari Ore in CO/CO2, H2/H2O, and H2 Atmospheres

Abstract The incorporation of hydrogen, which is a relatively unexplored reductant used during ferromanganese (FeMn) production, an attractive approach to lessen atmospheric gaseous carbon release. influence hydrogen on the pre-reduction carbonate-rich United Manganese Kalahari (UMK) ore from South Africa was investigated. Experiments were performed in 70 pct CO 30 2 (reference), H O, and 100 gas atmospheres at 700 °C, 800 900 °C. Calculated phase stability diagrams experimental results showed good correlation. process involved two reactions proceeding parallel, i.e ., higher oxides decomposition carbonates present ore. A thermogravimetric (TG) furnace employed for various atmospheres. calculated weight loss percentage determine degree rate pre-reduction. It found that oxidation state Fe- Mn-oxides lowered when treated O , whereas FeO metalized using . As intrinsic carbonates, majority thereof decomposed CO/CO atmosphere ≥ °C /H Additionally, reduction accelerated by increasing temperature employing hydrogen-containing (70 ). Scanning electron microscopy microprobe analysis revealed presence three phases pre-reduced ore: (i) Mn- Fe-rich, (ii) Mg- Ca-rich, (iii) Mg-, Si-, K-, Na-rich. also there no appreciable differences porosity decrepitation ores use potential carbonate-containing manganese as it well facilitated metallization Fe-oxides