Abstract: The reasons of deterioration of physical and chemical properties of molten chlorides during molten-salt chlorination of titania-rich slag were discussed,and a process of curing of Ca²⁺ and Mg²⁺ in molten chlorides was proposed which can improve the properties of molten chlorides,also the feasibility of the Ca²⁺ and Mg²⁺ curing process was verified by thermodynamics.The Gibbs free energy of curing reactions is less than zero,thus they can spontaneous reaction.When Na₂SO₄ as a curing agent and the temperature is below 1 073 K,both of k_p=[Ca²⁺] [SO₄^2-] and k_p=[Mg²⁺] [SO₄^2-] are less than 2.5×10^-3;when Na₃PO₄ as a curing agent and the temperature is below 1 173 K,k_p=[Ca²⁺] [PO₄^3-]^2/3<2.5×10^-6,k_p=[Mg²⁺] [PO₄^3-]^2/3<1×10^-7.