METHOD FOR PREVENTING ELUTION OF LEAD AND/OR NICKEL FROM COPPER ALLOY PIPING MATERIAL SUCH AS VALVE OR PIPE JOINT AND COPPER ALLOY PIPING MATERIAL, AND FLUID FOR USE IN CLEANING PIPING MATERIAL

摘要

A method for preventing the elution of lead and/or nickel from a copper alloy piping material such as a valve or a pipe joint into a fluid, which comprises cleaning at least the portion contacting with a fluid of the copper alloy piping material containing lead and/or nickel with a cleaning fluid containing nitric acid and hydrochloric acid as an inhibitor under a condition such that the temperature and time are sufficient for effectively removing lead and/or nickel, and forming a coating film on the surface of the portion contacting with a fluid by the action of the above-mentioned hydrochloric acid, to thereby effectively remove lead and/or nickel from the surface layer of the portion contacting with a fluid. The method allows the prevention of the elution of nickel through the removal of the nickel attached to the inner surface of a piping material with reliability and allows the efficient (with respect to treating temperature, treating time, and the like) treatment for preventing the elution of lead and/or nickel. The method also allows the utilization of products obtained by neutralization of various fluids having been used in treatments for preventing the above-mentioned elution as water for industrial use, which leads to great reduction of the cost for the above treatment and to the provision of an environmentally friendly technology.