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Dissolution of a Complex Borosilicate Glass at 60°C: The Influence of pH and Proton Adsorption on the Congruence of Short-Term Leaching

Published online by Cambridge University Press:  10 February 2011

P. K. Abraitis
Affiliation:
Dept. of Earth Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL
D. J. Vaughan
Affiliation:
Dept. of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL
F. R. Livens
Affiliation:
BNFL, Research & Technology, Waste Technology Group, Sellafield, Cumbria CA20 1PG
J. Monteith
Affiliation:
BNFL, Environmental Assessments, Consultancy Services, R202, Rutherford House, Risley, Warrington, Cheshire WA6 3AS
D. P. Trivedi
Affiliation:
BNFL, Environmental Assessments, Consultancy Services, R202, Rutherford House, Risley, Warrington, Cheshire WA6 3AS
J. S. Small
Affiliation:
BNFL, Environmental Assessments, Consultancy Services, R202, Rutherford House, Risley, Warrington, Cheshire WA6 3AS
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Abstract

The short-term dissolution behaviour of a complex borosilicate glass has been investigated by controlled pH leaching, surface titration and leach rate temperature dependence experiments. The results indicate that the rates, congruence and mechanisms of dissolution vary significantly with pH. At low pH, dissolution occurs via a proton-promoted mechanism which results in enhanced release of B and many network modifying elements (relative to Si). At 60°C in high pH media, dissolution is essentially congruent. Here, dissolution is surface reaction controlled and occurs via a hydroxyl-promoted network dissolution process. Selective leaching is favoured at low and near-neutral pH. Congruent dissolution occurs in solutions of pH greater than that at the point of zero net proton charge.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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