Copper ⇌ Alkali Ion Exchange of Alkali Aluminosilicate Glasses in Copper-Containing Molten Salt: II, Divalent Copper Salts, CuCl2 and CuSO4 |
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Authors: | Toshinobu Yoko Toshio Nishiwaki Kanichi Kamiya Sumio Sakka |
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Affiliation: | Department of Industrial Chemistry, Faculty of Engineering, Mie University, Tsu, Mie-Ken 514, Japan |
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Abstract: | The ion-exchange mechanism between copper and alkali ions, when 20R2O · 10Al2O3· 70SiO2 (R = Li, Na, and K) glasses are immersed in divalent copper-containing molten salts in air and nitrogen at 550°C, has been investigated. In molten CuCl2, the ion-exchange behavior in both air and nitrogen was very close to that in molten CuCl in air reported previously. This is explained by assuming that CuCl2 decomposes into CuCl and Cl2 at 550°C and the Cu+ ions thus formed mainly diffuse in glasses to replace alkali ions, where Cl2 acts as an oxidizing agent just like oxygen. In the case of molten CuSO4─2SO4, a small amount of Cu+ which is present in the molten state plays a primary role in the Cu ⇌ R+ ion exchange process, although the contribution of direct Cu2+⇌ 2R+ ion exchange cannot be ignored. |
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Keywords: | ion exchange copper alkalis glass aluminosilicates |
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