Solubility of KFe{sub 3}(CrO{sub 4}){sub 2}(OH){sub 6} at 4 to 35{degree}C
Journal Article
·
· Geochimica et Cosmochimica Acta
- Oregon Graduate Institute of Science and Technology, Portland, OR (United States)
The solubility of KFe{sub 3} (CrO{sub 4}){sub 2}(OH){sub 6}, the chromate analog of the sulfate mineral jarosite, was studied in a series of dissolution experiments. Experiments were conducted at 4 to 35{degrees}C and pH values between 1.5 and 3.0 using synthetic KFe{sub 3}(CrO{sub 4}){sub 2}(OH){sub 6}. The solids were kept in the reaction vessel for up to 6 months. Equilibrium was established in the experiments between 2 and 4 months. The log K{sub SP} for the dissolution reaction of KFe (CrO{sub 4}) {sub 2} (OH){sub 6} KFe{sub 3}(CrO{sub 4}) (OH){sub 6} + 6H{sup +} {r_equilibrium} K{sup +} + 3Fe{sup 3+} + 2CrO{sub 4}{sup 2+} + 6H{sub 2}O at 25{degrees}C is -18.4 {+-} 0.6. Based on this measured solubility product, the free energy of formation, {Delta}G{sub f}{degrees},{sub 298}, is -3305.5 {+-} 3.4 kJ mol{sup -1}. The dissolution experiments at 25{degrees}C indicate the formation of a FeCrO{sub 4}{sup +} complex.
- OSTI ID:
- 577436
- Journal Information:
- Geochimica et Cosmochimica Acta, Journal Name: Geochimica et Cosmochimica Acta Journal Issue: 20 Vol. 60; ISSN GCACAK; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
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