Phase Diagram for the NaOH-Al2O3-Na2CrO4-H2O System at (120 and 130) degrees C

Liu H; Xu HB; Zhang BZ; Tian Y; Zhang XF; Zhang Y; Zhang Y

Journal of Chemical and Engineering Data, Vol.59, No.11, 3314-3318, 2014

Liu H, Xu HB, Zhang BZ, Tian Y, Zhang XF, Zhang Y, Zhang Y

The phase diagrams of the NaOH-Al2O3Na2CrO4H2O system at (120 and 130) degrees C and in full NaOH concentration range were determined, and the crystallization zones of each solid were analyzed and discussed. The results show that Na2CrO4, Al2O3 center dot 3H(2)O, Na2O center dot Al2O3 center dot 1.25H(2)O, Na2O center dot Al2O3 center dot 2.5H(2)O, and NaOH are present as solid phases in the system at 120 degrees C, and Na2CrO4, Al2O3 center dot H2O, Na2O center dot Al2O3 center dot 1.25H(2)O, Na2O center dot Al2O3 center dot 2.5H(2)O, Na2O center dot Al2O3, and NaOH are present as solid phases in the system at 130 degrees C. These results can provide a basis for the separation of Na2CrO4 and Al2O3 from the concentrated alkali solution in the chromate cleaner production process.