Growth of Surface Layer during the Leaching of the Simulated Waste Glass and Its Barrier Effects on the Leaching

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石黒 勝彦; 佐々木 憲明; 川西 宣男*; 永木 裕; 山本 正男

Ishiguro, Katsuhiko; Sasaki, Noriaki; Kawanishi, N.*; Nagaki, Hiroshi; not registered

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Growth behavior of surface layers on simulated waste glass during two different types of leaching has been studied associated with their corrosion kinetics. Static and Soxhlet leach tests were performed in distilled water at a temperature of 100 degrees celsius. Auger and ESCA analyses of solid samples after leaching showed that the layers consisted of two or three sublayers which were distinguished by their different components. The transition elements Fe and Ni, the rare - earths Nd and La,and Zn were concentrated in the layers, while Si, B and alkali were depleted in most of the layers. Growth kinetics of the layers followed approximately linear relations for the two types of leaching. Growth rates and elemental profiles of the layers depended upon the leaching conditions. Comparison between the leaching rate and the thickness of the layer showed that layers did not work as effective diffusion barriers untill the threshold thickness, which depended on the layer structures.