Abstract: | A method is proposed for the determination of the equilibrium constantsk and k' for the reactions Zr+2I2–ZrI4=0 and 2I–I2=0, which is based on the measurement of the amount of iodine or zirconium liberated in the decomposition of zirconium tetraiodide on a heated surface in the process of establishing equilibrium. The decomposition of the tetraiodide was carried out at 900–1600 C on a tungsten filament. The temperature distribution between filament and vessel walls was neglected.The dependence of the sum of atomic and molecular iodine pressures
on zirconium tetraiodide pressure
was determined at 1430 C, and on temperature for
50 mm Hg. The values of kk'2 35 (mm Hg)3 at 1430 C and k 0.07 mm Hg at 400 C, found from the results, differ substantially from known thermodynamic data, but give good agreement between the authors' formula 1] and experimental results on the iodide process of zirconium purification. |