The solubility data of the Na2CrO4 + (NH4)(2)CrO4 + NaHCO3 + NH4HCO3 + H2O
system at 25 degrees C and 40 degrees C were determined, and the phase diag
ram was constructed. Furthermore, analyses and discussions are made on the
crystalline areas in the phase diagram. On the basis of these solubility da
ta, the utilization of Na+ and NH3 in the carbonating process for cleaner p
roduction of sodium dichromate was evaluated.