Equilibrium of the 2Al(l)+AlCl₃(g)=3AlCl(g) Reaction in the Subhalide Process of Aluminium (Study of Extractive Metallurgy of Aluminium (1))

Abstract

Equilibrium constants of a fundamental reaction of the aluminium subhalide process, 2Al(l)+AlCl₃(g)=3AlCl(g), were determined by the flow method using argon carrier between 1000°C and 1250°C. As a result of this experiment, equilibrium constants and standard free energy were obtained by the following equation:
logK_p(=P³AlCl⁄PAlCl₃)=−14,440⁄T+9.87
ΔG⁰_T=66,060−45.16T.
The heat of formation and entropy of AlCl(g) obtained from the experimental data and other thermodynamic values were −22,250 cal/mol and 48.7 cal/mol respectively. By the use of the equilibrium constants, the reaction ratio of aluminium trichloride was calculated at a reduced pressure and in argon carrier, respectively.