INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE

Case Study # 129

1.   Headline:  Aluminum is used instead of cadmium in the
     conventional electroplating technology for the elimination
     of Cd and CN containing waters and hydroxide sludge, while
     reducing operating costs.

2.   Background:  See below.

3.   Cleaner Production Principle: Material substitution

4.   Description for Cleaner Production Application:
     Conventional electroplating technology using aluminum
     instead of cadmium as the plating metal.  A thin layer of
     nickel is initially deposited on ferrous and aluminum die
     casting materials.  The pieces are dried using
     fluorohydrocarbons, and passed to the aluminum plating
     cell.  Using an electrolyte solution, an aluminum layer is
     applied to the nickel coating.  A post-treatment process
     may be applied to improve corrosion protection or for
     decorative appearance.

     Material/Energy Balance and Substitution

     FEEDSTOCKS:  Nickel - 18 g/m2, Al - 27 g/m2, electrolytic
     bath (recycled), electrical energy

     WASTES:  No wastewaters (electrolyte is recycled),
     evaporation of toluene from the bath (1-2 kg/hr)

     MEDIUM: Vapor

5.   Economics

     CAPITAL COST: 6 million Dfl - 40 m2/h plant

     OPERATION/MAINTENANCE: 50 - 75 Dfl/m2

     DISPOSAL & FEEDSTOCK:  10 - 15 Dfl/m2 reduction in
     operating costs, elimination of wastewater treatment and
     disposal costs

6.   Advantages

     FEEDSTOCK REDUCTION:  18 g of Ni, and 27 g Al is require
     compared to 180 g Cd, and 5 g CN in conventional
     technology

     WASTE PRODUCTION:  Cd and CN containing wastewaters are
     eliminated.  1-2 kg/h toluene vapor is produced.

     IMPACT: Elimination of Cd and CN  containing waters and
     hydroxide sludge, with reduced operating costs.  Discharge
     of the bath contents occurs after two years, and the
     materials are recycled.
7.   Constraints:  No information provided.

8.   Contact and Citation: Compendium on Low and Non-waste
     Technology, United Nations Economic and Social Counsel,
     Monograph "A Low-waste Electroplating Process of Aluminum
     in Non-aqueous Solvent (Sigal-Process)" ENV/WP.2/5/Add.125
9.   KEYWORDS:  the Netherlands, metal, electroplating,
     material substitution, cadmium, aluminum, nickel, toluene,
     ISIC 3813.

10.  Reviewers Comments:  This case study was originally
     abstracted for the US EPA Pollution Prevention Information
     Clearinghouse.  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: 400-125-A-332 )