Phase diagrams of complex multi-component aqueous chromium salt system arethe important theoretical bases for increasing the recovery ratio of chromium and reducing thepoisonous waste in the chromate production proces...Phase diagrams of complex multi-component aqueous chromium salt system arethe important theoretical bases for increasing the recovery ratio of chromium and reducing thepoisonous waste in the chromate production process. Phase equilibrium of multi-component system hasbeen calculated from the limited known data with thermodynamic models. The phase equilibriums ofKOH-K_2CrO_4-H_2O, KOH-KA1O_2-H_2O, NaOH-Na_2CrO_4-H_2O and NaOH-NaAlO_2-H_2O systems werecalculated with thermodynamic models. The solubilities of Cr and Al was measured in the systems atdifferent temperatures. The results were compared with experimental data and they are consistentwith each other. It shows that the lower concentration of KOH (or NaOH) is favorable for thecrystallization of KA1O2 (or NaA102) and higher concentration of KOH (or NaOH) is favorable for thecrystallization of K_2Cr0_4 (Na_2Cr0_4). Therefore, K_2CrO_4 (or Na_2CrO_4) can be separated fromKA1O_2 (or NaAlO_2) with controlling the KOH concentration in solutions of KOH-K_2CrO_4-KalO_2-H_2Oor NaOH-Na_2CrO_4-NaAlO_2-H_2O systems.展开更多
文摘Phase diagrams of complex multi-component aqueous chromium salt system arethe important theoretical bases for increasing the recovery ratio of chromium and reducing thepoisonous waste in the chromate production process. Phase equilibrium of multi-component system hasbeen calculated from the limited known data with thermodynamic models. The phase equilibriums ofKOH-K_2CrO_4-H_2O, KOH-KA1O_2-H_2O, NaOH-Na_2CrO_4-H_2O and NaOH-NaAlO_2-H_2O systems werecalculated with thermodynamic models. The solubilities of Cr and Al was measured in the systems atdifferent temperatures. The results were compared with experimental data and they are consistentwith each other. It shows that the lower concentration of KOH (or NaOH) is favorable for thecrystallization of KA1O2 (or NaA102) and higher concentration of KOH (or NaOH) is favorable for thecrystallization of K_2Cr0_4 (Na_2Cr0_4). Therefore, K_2CrO_4 (or Na_2CrO_4) can be separated fromKA1O_2 (or NaAlO_2) with controlling the KOH concentration in solutions of KOH-K_2CrO_4-KalO_2-H_2Oor NaOH-Na_2CrO_4-NaAlO_2-H_2O systems.
