| 摘要 |
Provided is a treatment method of a cooling water system, which is capable of forming by means of a basic treatment process an anticorrosion film having a good anticorrosion effect. The treatment method of a cooling water system, in which a basic treatment process is performed for forming an initial anticorrosion film on the surface of a metal member of the cooling water system by adding a phosphate and a zinc compound to the water system when the cooling water system starts to operate, wherein the basic treatment process is maintained for 5 to 36 hours under the conditions of a total phosphate concentration of 70-120 mg PO4/L, a zinc concentration of 10-30 mg Zn/L, a calcium hardness of 25-75 mg CaCO3/L, a pH of 6.0 or higher but less than 7.0, and once said basic treatment process has been performed a basic treatment is additionally performed with the pH set to 7.0 to 7.5. |
