INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE

CASE STUDY # 149

1.   Headline:  Electrolytic recovery unit at Sun Polishing and
     Plating reduces loss of nickel through dragout in the
     first standing rinse, allowing rinsewater to meet
     regulatory limits and reuse of nickel.

2.   Background:  See below.

3.   Cleaner Production Principle:  internal recycling

4.   Description of Cleaner Production Application:  A nickel
     plating line for lighting fixtures addressed loss of
     nickel through dragout in the first standing rinse with an
     electrolytic recovery unit.  The electrolytic chamber
     contains expanded steel mesh electrodes in a bed of inert
     glass beads.  The rinsewaters are pumped through the bed
     in successive rinses until a nickel concentration of 3 ppm
     is achieved.  The scouring action of the beads on the
     surface of the electrodes ensures that the ion
     concentration is maintained.  The electrodes are
     periodically removed when the deposits reach sufficient
     thickness, and the nickel is returned to the plating
     tanks.

     Material/Energy Balance Substitution

     FEEDSTOCKS: Rinsewaters from nickel plating

     WASTES:  Rinsewaters, nickel

     MEDIUM: Water, solid

5.   Economics

     CAPITAL COST:  Not reported

     OPERATION/MAINTENANCE: Requires less that 1/2 hour/day to
     maintain

     MONTHS TO RECOVER: 60

     DISPOSAL & FEEDSTOCK:  18 kg/week nickel recovered at
     about $7/kg, waste treatment costs eliminated

6.   Advantages

     FEEDSTOCK REDUCTION:  18 kg/week nickel

     WASTE PRODUCTION: Eliminates discharge of nickel
     containing rinsewaters

     IMPACT/PROBLEMS: The electrolytic recovery unit reduces
     the concentration of nickel in rinsewater from 300 ppm to
     3 ppm, which meets the regulatory limit of 5 ppm for
     nickel.  Thus, waste treatment costs are greatly reduced,
     and 18 kg/week of nickel can be reused.

7.   Constraints:  No information provided.

8.   Contacts and Citation: "Catalogue of Successful Hazardous
     Waste Reduction/Recycling Projects", Energy Pathways Inc.
     and Pollution Probe Foundation, prepared for Industrial
     Programs Branch, Conservation & Protection Environment
     Canada,  March, 1987, page 42.

9.   Keywords:  United States, USA, metal, electroplating,
     recycling, light fixture, nickel, electrolysis, plating,
     rinsing, ISIC 3000.

10.  Reviewer's Comments:  This case study was originally
     abstracted for the US EPA's Pollution Prevention
     Information Clearinghouse from the Canadian publication
     "Catalogue of Successful Hazardous Waste
     Reduction/Recycling Projects."  It underwent a UNEP IE
     funded technical review in 1994 for quality and
     completeness.  It was edited for the ICPIC diskette in
     July 1995.

( Docno unep05: 450-003-A-350 )