The separation of cadmium and nickel from sulfate leach liquors of waste Ni-Cd batteries is investigated by using ternary phase diagrams. Experimental studies are carried out to obtain ternary phase diagrams of nickel sulfate, cadmium sulfate and water mixture at 40 degrees C and 80 degrees C. The eutectic point is determined to be composed of CdSO(4 center dot)8/3H(2)O + NiSO(4 center dot)6H(2)O and CdSO4 center dot H2O + NiSO(4 center dot)6H(2)O, for 40 degrees C and 80 degrees C, respectively, while two univariant curves and two crystallization regions are observed corresponding to CdSO(4 center dot)8/3H(2)O and NiSO(4 center dot)6H(2)O at 40 degrees C, CdSO4 center dot H2O and NiSO(4 center dot)6H(2)O at 80 degrees C. Both low (40 degrees C) and high (80 degrees C) temperature systems belong to a simple saturated type while no double salts or solid solutions exist. (C) 2014 Elsevier B.V. All rights reserved.