Solubility of ZnO and hydrolysis of ZnCl2 in KCl melts
- 1 January 1991
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions
- Vol. 87 (18) , 2955-2960
- https://doi.org/10.1039/ft9918702955
Abstract
An oxide-ion specific electrode has been used to measure the solubility of ZnO in KCl by potentiometric titration of ZnCl2 in KCl with oxide. The solubility product of ZnO was found to be 2.3 × 10–8 mol2 kg–2 at 1073 K. On the addition of ZnCl2 to oxide ion solutions a zincate species was formed, ZnO2– 2, with a formation constant of 3 × 10–12 mol3 kg–3. Attempts to isolate K2ZnO2 have been unsuccessful. The effect of HCl on dissolved oxide ion in ZnCl2(33.3 mol.%)–KCl has been studied over the temperature range 733–873 K. Treatment of this salt with HCl yields an oxide concentration of ca. 10–10 mol. kg–1, but this rapidly increases to ca. 10–3 mol kg–1 when the salt is held under argon, through reaction with trace amounts of water in the gas. The equilibrium reaction: H2O(g)+ 2Cl–⇌ 2HCl(g)+ O2– has been studied and the equilibrium constant is given by: log K= 2.514 – 8163/TKeywords
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