HEAT-RESISTANT CORROSION-PREVENTIVE COATING FILM

PURPOSE:To form the title coating film which has good adhesiveness, uniformly, and denseness, provides improved corrosion resistance, and is free from trouble due to silica scaling, by attaching a mixture containing an alkaline earth metal carbonate to the surface of a heat exchanger tube in a high-temperature section with an aluminate binder. CONSTITUTION:This heat-resistant corrosion-preventive coating film is formed by attaching a mixture containing at least one alkaline earth metal carbonate to the surface of a heat exchanger tube in a high-temperature section of, e.g., an oil-fired boiler, a boiler for power generation or a boiler for sodium carbonate recovery with an aluminate binder (e.g., an aqueous solution of sodium aluminate). Since an alkaline earth metal carbonate is dispersible thoroughly in an aluminate binder, a coating film with good adhesiveness, uniformity, and denseness can be obtained, the corrosion resistance can be remarkably improved and there is nothing to worry about the trouble due to silica scaling in a process of concentrating a waste liquor in a boiler for sodium carbonate recovery.