DETERMINATION OF LEACHING REACTION MECHANISM OF SYNTHETIC CaMoO4 IN H2C2O4 SOLUTIONS

Abstract

Leaching experiments of CaMoO4 in H2C2O4 solutions were carried out to investigate stoichiometry and mechanism of leach reactions. The quantities of dissolved Mo and Ca in the leach solutions were determined by the ICP-OES analysis. Leach residue was separated from leach solutions by filtration. Characterizations of leach residues and solid products obtained by evaporation of leach solutions were carried out by XRD, TGA-DTA-MS and FT-IR analyses. It was found that the leach reaction took place in two steps as a consecutive reaction. While in the first step Ca[MoO3(C2O4)(H2O)] was formed, in the second step H-2[(MoO3)(2)(C2O4)] was formed by reaction of hydrolyzed Ca[WO3(C2O4)H2O] formed in the first step with H2MoO4. By considering results of leach experiments and analyses, the overall dissolution reaction was determined as