Method for treating brass

Abstract

Brass articles having leachable lead are contacted with an aqueous caustic solution that contains a chelating agent. The brass article can optionally be post-treated by contacting them with an aqueous solution containing hydrogen peroxide.

What is claimed:  
     
         1 . A method of treating brass articles to reduce leachable lead therein which comprises the steps of: contacting a brass article with a primary treatment solution to reduce leachable lead therein, the primary treatment solution comprising an aqueous caustic solution containing a chelating agent; and contacting the brass article with a post-treatment solution after being contacted with the primary treatment solution, said post-treatment solution comprising an aqueous solution containing hydrogen peroxide.  
     
     
         2 . A method of treating brass articles to reduce leachable lead therein according to  claim 1 , wherein the chelating agent is selected from the group consisting of phosphonic acids, aminopolycarboxlic acids and mixtures thereof.  
     
     
         3 . A method of treating brass articles to reduce leachable lead therein according to  claim 1 , wherein the chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid, N-hydroxyethylethylene-diaminetriacetic acid, diethylenetriaminepentaacetic acid and mixtures thereof.  
     
     
         4 . A method of treating brass articles to reduce leachable lead therein according to  claim 1 , wherein the caustic solution includes a caustic component selected from the group consisting of an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate and mixtures thereof.  
     
     
         5 . A method of treating brass articles to reduce leachable lead therein according to  claim 1 , wherein the brass article is sonicated during contact with the primary treatment solution.  
     
     
         6 . A method of treating brass articles to reduce leachable lead therein according to  claim 1 , wherein the brass article is contacted with a pretreatment solution prior to being contacted with the primary treatment solution, said pretreatment solution comprising an aqueous solution containing an hydrogen peroxide.  
     
     
         7 . A method of treating brass articles to reduce leachable lead therein according to  claim 6 , wherein the brass article is sonicated during contact with the pretreatment solution.  
     
     
         8 . A method of treating brass articles to reduce leachable lead therein according to  claim 1 , wherein the brass article is contacted with a post-treatment solution after being contacted with the primary treatment solution, said post-treatment solution comprising an aqueous solution containing hydrogen peroxide.  
     
     
         9 . A method of treating brass articles to reduce leachable lead therein according to  claim 1 , wherein the brass article is selected from the group consisting of faucets, valves and fittings.