Accession Number : ADA191818

Title :   The Hydrothermal Dissolution of Perovskite (CaTiO3),

Corporate Author : ATOMIC ENERGY RESEARCH ESTABLISHMENT HARWELL (ENGLAND)

Personal Author(s) : Myhra, S ; Bishop, H E ; Riviere, J C

PDF Url : ADA191818

Report Date : Nov 1986

Pagination or Media Count : 38

Abstract : Perovskite (CaTiO3) has been exposed to hydrothermal chemical attack in aqueous solution. Dependence on temperature (150-250 C) and on duration of attack (1 to 35 days) have been investigated. It was found that a precipitated surface layer was formed. The thickness of this layer ranged from a few mono-layers to several hundred nanometers for the least and the most severe hydrothermal conditions, respectively. The composition of the layer, as deduced by surface analytical techniques, suggests that (i) there is congruent dissolution of the perovskite surface, (ii) a TiO2 precipitate layer is formed, and (iii) the presence of silica and CO2 in solution do not appear to affect substantially the mechanism of the rate of dissolution. Keywords: Nuclear waste disposal, Hydrothermal dissolution, Surface analysis.

Descriptors :   *PEROVSKITES, *RADIOACTIVE WASTES, *WASTE DISPOSAL, *CHEMICAL ATTACK(DEGRADATION), *DISSOLVING, SILICON DIOXIDE, SURFACE ANALYSIS, WATER, ETCHING, ION BOMBARDMENT, CALCIUM, TITANIUM OXIDES, CRYSTALLOGRAPHY, THERMAL DEGRADATION, AUSTRALIA

Subject Categories : Geology, Geochemistry and Mineralogy
      Physical Chemistry
      Radiation Pollution and Control

Distribution Statement : APPROVED FOR PUBLIC RELEASE