Experimental studies of aluminum solubility and speciation in brines
The solubility of gibbsite -- Al(OH){sub 3} -- has been measured in (a) Na{sup +}-H{sup +}-Al{sup 3+}-Cl{sup {minus}} brines to 70{degrees}C and 5 molal ionic strength; (b) Na{sup +}K{sup +-}OH{sup {minus}}-Cl{sup {minus}}-Al(OH){sub 4}{sup {minus}} brines to 80{degrees}C and 5 molal; and (c) at 50{degrees}C in 0.1 molal NaCl with the H{sup +} concentration controlled by acetate, bis-tris and tris buffers at -log(H{sup +}) -- 3 to 9. The activity coefficient ratios, ({gamma}Al{sup 3+})/({gamma}H{sup +}){sup 3} and ({gamma}Al(OH){sub 4}{sup {minus}})/({gamma}OH{sup {minus}}), have been modeled in the 0--100{degrees}C range using the Pitzer ion interaction treatment. Complexes of Al{sup 3+} with acetate and Al(OH){sub 4}{sup {minus}} with bis-tris have been identified. Our results indicate that complexation of Al{sup 3+} by chloride is insignificant in this temperature range. The formation constants of Al(OH){sup 2+} have been quantitatively determined by potentiometric titrations in the range 25--125{degrees}C and 0--5 molal ionic strength in NaCl media. After correcting for complexation of aluminum ions with the buffers, our solubility data at near neutral pH's are shown to be in quantitative agreement with the potentiometric results.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5524064
- Report Number(s):
- CONF-920761-4; ON: DE92010448
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ACETATES
ALUMINIUM
ALUMINIUM COMPLEXES
ALUMINIUM COMPOUNDS
ALUMINIUM HYDROXIDES
BRINES
CARBOXYLIC ACID SALTS
CHARGED PARTICLES
CHLORINE IONS
COMPLEXES
ELEMENTS
GIBBSITE
HYDROGEN COMPOUNDS
HYDROXIDES
IONS
METALS
MINERALS
OXIDE MINERALS
OXYGEN COMPOUNDS
PH VALUE
POTENTIOMETRY
SODIUM IONS
SOLUBILITY
TITRATION
WATER