The kinetics and mechanism of reduction of a serpentine ore in CO/CO_2 mixtures are investigated. For pressed pellets made in the laboratory, the reaction rate is found to be controlled predominantly by chemical reaction at the internal pore surfaces. or by diffusion with in individual ore grains. After the first minute of reduction, there is little evidence of cotnrol by diffusion within the pores of the pellet. The extent of reduction is found to be enhanced in a temperature range between that at which serpentine decomposes and that at which olivine crystallises; and a change in apparent activiation energy for reduction concides with olivine crystallisation. This change is more pronounced for nickel with is explained in terms of the relative solubilities of nickel and iron in olivine.
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