Resource recycling, journal of recycling reuse and waste reduction: Edited by J. Poweli, published bimonthly by Resource Conservation Consultants, 1615 N.W. 23rd, Suite One, P.O. Box 10540, Portland, Oregon 97210, U.S.A. Subscription rates: $18 per year (outside U.S.A., add $3.50 per year). Single copy rate: $3.00

Abstract

The oxygen potentials over the oxide phase mixtures Ti2O3-Ti3O5 and Ti3O5−Ti4O7 were determined between 1180 and 1330 K by studying the oxide mixture-carbon-CO(g) equilibria, involving measurements of the equilibrium pressure of CO as a function of temperature using a simple manometric technique. The measured values of the CO pressure can be represented by the following equations: for the reaction 2Ti3O5 + C = 3Ti2O3 + CO log pco (kPa) = − 10540 ± 690T(K) + (4.827 ± 0.55) and for the reaction 3Ti4O7 + C = 4Ti3O5 + COlog pco(kPa) = −10270 ± T(K) + (5.244 ± 0.90) The oxygen potentials over the two oxide mixtures were calculated using these equations and the reported free energy of formation of CO and can be given as follows: for the reaction 6Ti2O3 + O2 = 4Ti3O5 ΔG(kJ (molO2)−1) = − (623.4 ± 27) + (86.3 ± 21) × 10−3T(K) and for the reaction 8Ti3O5 + O2 = 6Ti4O7 ΔG(kJ (molO2)−1) = −(616.5 ± 46) + (102.3 ± 35.7) × 10−3T(K)