Molten salt is as the main carrier. Because it has good thermal conductivity, high heat transfer coefficient, weak corrosion and other advantages, so it is widely used in electrolytic metallurgy, chemical industry, energy technology and other fields of science and technology.

    Commonly used molten salt is a mixture of nitrite and nitrate. It is composed of 40%NaNO₂, 7% NaNO₃, 53% KNO_3. The melting point of the molten salt is 142⁰c, and the boiling point is 680⁰c. Between high temperature of 350⁰C~540⁰C, it is the most stable heat carrier.
    If common molten salt exceed 550⁰C, molten salt began to instability and NaNO₂ slowly breaks down. If it contacts with air, 2NaNO₂+ O₂=2NaNO₃. With temperature increasing, when the temperature of molten salt exceeds 620^oC, 4KNO₃ = 2k₂O+2N₂ + 5O₂ and molten salt goes bad. At the same time, molten salt would attach on the pipe wall. If so, it will influence to use for molten salt pump and molten salt bath of molten salt heat system. With the temperature increasing, decomposition would become quickly until the molten salt completely is decomposed.