Methods for processing battery waste and other lead-contaminated materials

• US 5,173,277 A
• Filed: 02/22/1991
• Issued: 12/22/1992
• Est. Priority Date: 02/22/1991
• Status: Expired due to Fees

• Current Assignee: NL Industries Incorporated 3000 North SAM Houston Parkway East
• Original Assignee: NL Industries Incorporated (Valhi Holding Company)
• Inventors: Kube, Wolfram H., Montgomery, Alistair H.
• Primary Examiner(s): Nguyen, Nam X.
• Assistant Examiner(s): SQUILLANTE JR, EDWARD
• Application Number:
  US07/659,243
• Time in Patent Office: 669 Days
• Field of Search: 429/49, 423/92, 423/98, 423/619, 134/26, 75/432, 75/725
• US Class Current: 423/92
• CPC Class Codes: C08J 11/06 without chemical reactions
• CPC Class Codes: H01M 10/54 Reclaiming serviceable parts of waste accumulators
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling
• CPC Class Codes: Y02W 30/84 Recycling of batteries or fuel cells

Abstract

The present invention is directed to improved methods for processing battery wastes, batter casing debris and other lead contaminated materials. The improved processes of the present invention provide less environmentally stressful methods for recovering lead from such materials while at the same time producing scrap or recyclable ebonite and plastics having reduced and environmentally acceptable lead and leachable lead levels. Most of the lead is first removed by trommel scrubbing. In another aspect of the present invention ebonite and other hard surface materials to which are adhered lead contaminants are mixed with water and abraded in a high energy scrubber to remove the adhered contaminants prior to separation of the cleaned ebonite from solution. This simple and environmentally preferred hydromechanical process provides clean scrap or recyclable ebonite. In another aspect of the present invention, plastic and other soft materials contaminated with lead are mixed with a solution having a pH greater than about 7, preferably about 1-5 percent-by-weight alkali hydroxide solution, to dissolve lead contaminants. Separation of particulates produces clean scrap or recyclable plastic while carbonation of the wash water permits recovery of lead carbonate. Finally, the present invention provides methods for controlling dust contamination prior to and during processing by spraying the fine, raw materials with an aqueous solution of a wetting agent, preferably about 2 percent-by-weight alkali carbonate, bicarbonate or sequicarbonate in water.

Claims

1. A method for reducing the lead and leachable lead content of fragments of lead storage batteries and battery debris, to which are adhered lead contaminants such as lead sulfate, lead oxides, metallic lead and mixtures thereof, comprising:

abrading said lead contaminants from said fragments sized between about 10 mesh and about 1.5 inches by scrubbing in an attrition scrubber rotating at about 800 to about 1500 rpm a mixture comprising from about 60 to about 80 percent-by-weight of said lead-contaminated fragments in water for a time of about 15 minutes to about 2 hours and at a temperature between about 40°

F. and about 120°

F.;

transferring the abraded mixture to a floatation tank; and

separating clean fragments from water containing the abraded lead contaminants by removing the floating, clean fragments from the surface of the said mixture in said floatation tank.

2. A method for reducing the lead and leachable lead content of hard surface materials comprising lead storage batteries and battery debris to which are adhered lead contaminants, comprising:

abrading said lead contaminants from said hard surface materials by scrubbing in a high energy scrubber rotating at about 800 to about 1500 rpm a mixture comprising from about 30 to about 80 percent-by-weight of said lead contaminated materials in water; and

separating hard surface materials from which said lead contaminants have been abraded from said water containing the abraded contaminants.

3. The method of claim 2 wherein said hard surface materials have a density less than the density of water.

4. The method of claim 2 wherein said abrading is performed in an attrition scrubber and said mixture comprises from about 60 to about 80 percent-by-weight solids.

5. The method of claim 2 comprising sizing said hard surface materials to between about 10 mesh and about 1.5 inches prior to said abrading.

6. The method of claim 3 wherein said hard surface materials are selected from the group consisting of ebonites, hard rubbers and mixtures thereof.

7. The method of claim 4 wherein said contaminated, hard surface materials are scrubbed in said attrition scrubber for about 15 minutes to about 2 hours.

8. A method for processing a mixture of lead-contaminated materials comprising fragments of lead storage batteries and battery debris, comprising:

sizing said lead batteries and battery debris of said mixture to be less than about 4.0 inch;

mixing said sized mixture with an aqueous solution in a trommel scrubber until said fragments are sized to less than about 1.5 inch;

washing with a wash solution to remove lead fines;

separating said lead fines from said wash solution;

recycling the separated wash solution for use in wetting said mixture of lead-contaminated materials in said trommel scrubber;

scrubbing a mixture comprising about 60 to about 80 percent-by-weight of said sized fragments from said trommel scrubber in water in an attrition scrubber rotating at about 800 to about 1500 rpm to abrade lead contaminants from the surface of said materials;

separating materials from which said lead contaminants have been abraded from said water containing the abraded contaminants;

separating said abraded contaminants from said water;

recycling said separated water for use in said attrition scrubber;

contacting said lead-contaminated materials with an aqueous solution having a pH greater than about 7 to leach said lead contaminants therefrom;

separating materials from which said lead contaminants have been leached from said aqueous solution containing leached contaminants;

separating said leached contaminants from said aqueous solution; and

recycling the separated aqueous solution for use in wetting said lead-contaminated materials.