Carbon in Solidphase Reduction of Oxides

Abstract:

The gasphase-solidphase model is used to explain the results of solid chromite ore carbothermic reduction. The reducing agent is carbon atoms. Carbon is brought to the surface of chromite grains by gaseous carbon-containing molecules and radicals, such as C₃O₂, CH₄, CH₃, CH₂, CH, C₂H₂ and other carbon containing particles. Gas particles penetrate a piece of ore through the pores and cracks. Active carbon atoms C are formed by the dissociation of gaseous particles. Reduction by carbon is carried out on the chromite grain surface due to the cations and anions diffusion in the oxide lattice towards the grain surface. Porosity of chromite ores is experimentally defined under reducing conditions; it is estimated at up to 20 – 25 vol.%. Up to 1/4 of porosity is accounted for macropores and macrocracks that have the radius of over 50 microns, the remaining porosity share is accounted for the pore dimensions that are estimated at 0.5 – 50 microns in radius. The carbon presence in the pores of partially reduced ores is deduced based on experiment. There is also carbon in the reduced metal that is situated deep in the lump ore. The experimental results agree with the gasphase-solidphase reduction model.

• Periodical: Materials Science Forum (Volume 870)
• Pages: 578-583
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.870.578
• Online since: September 2016
• Authors: A.V. Senin*
• Keywords: Carbothermic Reduction, Chromite Ores, Gaseous Hydrocarbons, Gaseous Radicals, Solidphase Reduction

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