Symposium on Characterization of Minerals, Metals, and Materials held during The-Minerals-Metals-and-Materials-Society Annual Meeting and Exhibition (TMS), California, Amerika Birleşik Devletleri, 16 - 20 Şubat 2014, ss.351-359
In this study, leaching characteristics of CaWO4 in H2C2O4 solutions and reaction stoichiometry were investigated. Solutions were taken from the reactor and dissolved Ca and W were analyzed quantitatively by ICP-OES instrument. Leach residues and solid products obtained by evaporation of leach solutions were characterized by XRD, TGA-DTA-MS and FT-IR analyses. It was found that leaching reaction took place via decomposition of Ca[WO3(C2O4)H2O] intermediate chelate compound formed in the first step to H-2[WO3(C2O4)H2O] final chelate compound formed in the second step. It was also seen that H-2[WO3(C2O4)H2O] chelate compound was not stable and it began to decompose by forming H2WO4 precipitate after a certain time. Overall leach reaction was determined as CaWO4 ((s)) + 2 H2C2O4 ((aq))+ H2O ((l)) - H-2[WO3(C2O4)H2O] ((aq)) + CaC2O4H2O ((s)).