Influences of Alkali Fluxes on Direct Reduction of Chromite for Ferrochrome Production by D
http://dx.doi.org/10.17159/2411-9717/2018/v118n12a9 Influences of alkali fluxes on direct reduction of chromite for ferrochrome production by D. Paktunc*, Y. Thibault*, S. Sokhanvaran*, and D. Yu* process. In comparison to the conventional $+DE;CFC smelting processes, this prereduction process Prereduction and flux-aided direct reduction of chromite provide lowers the overall energy consumption and significant advantages in reducing energy consumption and greenhouse greenhouse gas emissions by about one-third gas emissions during ferrochrome production. In this investigation, a (Naiker, 2007). comparative evaluation of the influences of several alkali fluxes was Prereduction of chromite with the use of carried out based on experimental observations supplemented by various fluxes or additives has been the topic advanced material characterization and thermodynamic predictions. Direct of many studies over at least three decades. reduction of a chromite ore with alkali fluxes at 1300°C for 1 hour The additives tested since 1986 include produced (Cr,Fe)7C3 type alloys with Cr/Fe mass ratios from 0.7 to 2.3. borates, NaCl, NaF, and CaF2 (Katayama, Among the alkali fluxes, reduction aided by NaOH resulted in a high Tokuda, and Ohtani, 1986), CaF2 and NaF degree (85%) of Cr metallization with the ferrochrome alloy being (Dawson and Edwards, 1986), K2CO3, CaO, Cr4.2–4.6Fe2.4–2.8C3. The formation of liquid slag, which facilitated Cr SiO2, Al2O3, and MgO (van Deventer, 1988), metallization, was limited by the formation of NaAlO2 between 800 and 1300°C. This, in turn, restricted the collection and transport of the charged granite and CaF2 (Nunnington and Barcza, ionic Cr species (i.e.
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