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Nepheline Crystallization in Nuclear Waste Glasses: Progress Toward Acceptance of High‐Alumina Formulations
Author(s) -
McCloy John S.,
Schweiger Michael J.,
Rodriguez Carmen P.,
Vienna John D.
Publication year - 2011
Publication title -
international journal of applied glass science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 34
eISSN - 2041-1294
pISSN - 2041-1286
DOI - 10.1111/j.2041-1294.2011.00055.x
Subject(s) - nepheline , aluminosilicate , nepheline syenite , materials science , crystallization , radioactive waste , mineralogy , sodium aluminosilicate , ternary operation , nuclear chemistry , thermodynamics , chemistry , physics , biochemistry , computer science , programming language , catalysis
Historical data have been critically compiled and analyzed for investigating the quantity of nepheline ( NaAlSiO 4 ) precipitated as a function of composition in simulated nuclear waste glasses. To understand compositional effects two primary methods were used: (1) investigating the Al 2 O 3 – SiO 2 – Na 2 O ternary while filtering for different B 2 O 3 levels and (2) creating a quadrant system consisting of compositions reduced to two representations: (i) the nepheline discriminator ( ND ) which depends only on the SiO 2 content by weight normalized to the total weight of the Al 2 O 3 – SiO 2 – Na 2 O submixture and (ii) the optical basicity ( OB ) which contains contributions from all constituents in the glass. Nepheline precipitation is expected to be suppressed at high SiO 2 levels ( ND > 0.62) or at low basicities ( OB < 0.55–0.57). Changes in sodium aluminosilicate glass OB values due to additions of CaO and B 2 O 3 correlate with the observed effects on nepheline formation. It is proposed that additional composition space is available for formulating high waste loading, high‐ Al 2 O 3 nuclear waste glasses when consideration is given to location on the Al 2 O 3 – SiO 2 – Na 2 O submixture as well as OB .