Solubility behavior of titanium(IV) oxide in alkaline media at elevated temperatures
A platinum-lined, flowing autoclave facility was used to investigate the solubility behavior of titanium dioxide (TiO{sub 2}) in aqueous sodium phosphate, sodium hydroxide and ammonium hydroxide solutions between 290 and 560 K. Baseline Ti(IV) solubilities were found to be on the order of one nanomolal, which were enhanced by the formation of anionic hydroxo- and phosphato-complexes. The measured solubility behavior was examined via a titanium(IV) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reaction equilibria were obtained from a least-squares analysis of the data. The existence of three new Ti(IV) ion complexes is reported for the first time: Ti(OH){sub 4}(HPO{sub 4}){sup =}, Ti(OH){sub 5}(H{sub 2}PO{sub 4}){sup =} and Ti(OH){sub 5}(HPO{sub 4}){sup 3{minus}}. The triply-charged anionic complex was the dominant Ti(IV) species in concentrated, alkaline phosphate solutions at elevated temperatures. This complex is expected to exhibit C.N. = 4 (i.e., Ti(OH){sub 2}OPO{sub 4}{sup 3{minus}}). A summary of thermochemical properties for species in the systems TiO{sub 2}-H{sub 2}O and TiO{sub 2}-P{sub 2}O{sub 5}-H{sub 2}O is also provided. 21 refs., 9 figs., 6 tabs.
- Research Organization:
- Knolls Atomic Power Lab., Schenectady, NY (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC12-76SN00052
- OSTI ID:
- 5546304
- Report Number(s):
- KAPL-4729; ON: DE92009551
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
AQUEOUS SOLUTIONS
AUTOCLAVES
CHALCOGENIDES
DISPERSIONS
MATERIALS
MINERALS
MIXTURES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
RADIOACTIVE MATERIALS
RADIOACTIVE MINERALS
RUTILE
SOLUBILITY
SOLUTIONS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TITANIUM PHOSPHATES
TRANSITION ELEMENT COMPOUNDS