The surface chemical properties of scheelite (CaWO4) I. The scheelite/water interface and CaWO4 solubility
1987; Elsevier BV; Volume: 25; Issue: 2-4 Linguagem: Inglês
10.1016/0166-6622(87)80315-3
ISSN1873-4340
AutoresK.I. Marinakis, G. H. Kelsall,
Tópico(s)Radioactive element chemistry and processing
ResumoThe solubility of scheelite was determined as a function of pH at a constant ionic strength of 10−2 kmol m−3 NaClO4, and a thermodynamic solubility product of (8.8 ± 0.1) × 10−9 at 298 K calculated by extrapolation of the experimental values to zero ionic strength. The dissolution of scheelite was found to be incongruous, the solubility of tungstate being larger than that of calcium above pH 6. Addition of carbonate, silicate species (froth flotation depressants), dodecyl sulphate or decyl phosphonate ions (potential collectors in scheelite flotation) increased the tungstate concentration in solution at pH values above 6, whereas the calcium concentration remained unchanged. Anion-exchange type reaction between these various anions in solution and the tungstate ions of the crystal lattice is postulated to explain this behaviour.
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