Low lead release plumbing components made of copper based alloys containing lead, and a method for obtaining the same
AssigneeEuropa Metalli S.p.A.
InventorAldo Giusti
Life of this patent
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Abstract
A method for treating a component made of a copper-based alloy containing lead. The component has Pb and Pb salts on a surface thereof. The method includes the step of etching the surface of the component selectively to remove almost entirely the Pb and Pb salts from the surface. The etching includes treating the surface with an acidic aqueous solution that is a) a non-oxidizing acidic aqueous solution of an acid capable of forming soluble Pb salts or b) an oxidizing acidic aqueous solution of an organic acid mixed with peroxide. The method also includes the step of passivating the etched surface whereby to inhibit release of any Pb or Pb salts remaining in the component when the passivated surface is in contact with water.
Claims20
A method for treating a metal for use in water distribution, said method comprising the steps of:
- (i) providing a water distribution component comprising a copper-based alloy containing lead as an alloy element a portion of the lead being segregated in a plurality of discrete concentrations at a surface of the water distribution component in the form of lead or lead salts;
- (ii) etching the surface of the component selectively to remove almost entirely the Pb and Pb salts from the surface, said etching comprising treating said surface with an acidic aqueous solution selected from the group consisting of a) a non-oxidizing acidic aqueous solution comprising an acid capable of forming soluble Pb salts and, b) an oxidizing acidic aqueous solution comprising an organic acid mixed with peroxide;
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- (iii) passivating said etched surface whereby to inhibit release of any Pb or Pb salts remaining in the component when the passivated surface is in contact with water.
A method for treating a metal for use in water distribution, said method comprising the steps of:
- (i) providing a water distribution component comprising a copper-based alloy containing lead as an alloy element, said component having a nonuniform distribution of lead with a surface of the component being enriched in lead that is segregated from the alloy, whereby said component comprises said alloy and said segregated lead;
- (ii) providing an acidic aqueous solution comprising an acid, said acid being selected and said acidic aqueous solution having a molarity, pH and temperature such that, upon immersion of the surface of the component in the acidic aqueous solution for a sufficient time, the acidic aqueous solution etches the surface and selectively removes almost entirely the segregated lead without affecting the alloy;
- said acidic aqueous solution being selected from the group consisting of (a) a non-oxidizing acidic aqueous solution comprising an acid capable of forming soluble Pb salts, and (b) an oxidizing acidic aqueous solution comprising an organic acid mixed with peroxide;
- (iii) immersing said surface in said acidic aqueous solution for a time sufficient selectively to remove almost entirely the segregated lead with the alloy being unaffected by the immersing;
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- (iv) passivating the etched surface by treatment of the etched surface with a basic aqueous solution comprising a base, said base being selected and being present in the basic aqueous solution at a molarity such that the treatment forms an insoluble chemical layer on the etched surface that resists corrosion and prevents release of lead from the component.
Dependencies are inferred from the claim text.