HEDP•Na4 is used as detergent for metal and nonmetal. In dyeing industry, Tetra Sodium Salt of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid is used as peroxide stabilizer and dye-fixing agent; In non-cyanide electroplating, Tetra Sodium Salt of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid is used as chelating agent.