Mineralogical Research on Tooeleite |
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| Institution: | ;1.School of environmental resource and engineering;2.SWUST |
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| Abstract: | Tooeleite Fe6(AsO3)4SO4(OH)4·4H2O is a ferric arsenite sulfate mineral only found in acid mine drainage at present, which has environmental significance for arsenic remediation because of its high stability in the regolith. The authors synthesized tooleite using temperature-constant water batch reactor, and for the first time studied by X-ray diffraction (XRD), infrared (IR) and Raman spectroscopy. The XRD result indicates tooeleite can form more crystalline solids in an acid environment than in an alkaline environment; the characteristic peak at FTIR of 770 cm-1is attributed to stretch vibration of As-O; the characteristic peaks at Raman of 663, 609, 512, 455 and 365 cm-1are attributed to the stretch vibration of As-OH (ν3), asymmetric stretch vibration (ν5), asymmetric bending vibration (ν4) of AsO33- and bending vibration of O-As-O; the incongruent dissolution occurs when PH of solution is higher than 3. Low Ph environmental benefits for formation of more high crystalline tooeleite. The batch experiment determined for the first time the solubility product (Ksp) and the standard Gibbs free energy of the reaction, which are 107.7 and-3605 kJ/mol, respectively. |
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