Potential—pH diagrams of Cr-H2O system at elevated temperatures
(1. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190, China;
2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China)
2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China)
Abstract: The potential—pH diagrams of the Cr-H2O system at temperatures of 298, 323, 373 and 423 K were established through thermodynamic calculation with coupling of experimental results. The potential—pH diagram at 298 K agrees well with the previously reported results. Based on the potential—pH diagrams of the Cr-H2O and Fe-H2O systems, IR spectra and XRD pattern, the existence forms of iron in the potassium chromate were analyzed, and the methods of iron removal were investigated. The results show that the existence forms of iron in the potassium chromate are potassium ferrate. These results are instructive and helpful to the hydrometallurgical processing of chromite ore.
Key words: Cr-H2O system; thermodynamic calculation; potential—pH diagram; iron removal; potassium chromate