Number
067-EN
Section
General Section
Use
Sector
Building and construction work
General manufacturing, e.g. machinery, equipment, vehicles, other transport equipment
Manufacture of fabricated metal products, except machinery and equipment
Function
Corrosion inhibitor
Process
Treatment of articles by dipping and pouring
Product category
Metal surface treatment products
Application
Metal surface treatment for diverse industries
Abstract
An electroplating company in Denmark made changes in the production process for galvanising. They substituted zinc cyanide by zinc chloride.
Substituted substances
Zinc cyanide
CAS No. 557-21-1 EC No. 209-162-9 Index No.
Chemical group
Cyanide
Alternative Substances
Zinc chloride
CAS No. 7646-85-7 EC No. 231-592-0 Index No. 030-003-00-2
Chemical group
Chloride
Classification: hazard statements
H302 Harmful if swallowed
H314 Causes severe skin burns and eye damage
H400 Very toxic to aquatic life
H410 Very toxic to aquatic life with long lasting effects
Reliability of information
Evidence of implementation: there is evidence that the solution was implemented and in use at time of publication
Reason substitution
ecotoxicity
other toxic effects
Hazard Assessment
Substance to be substituted: Zinc cyanideis not listed in the SUBSPORTplus Database and has no harmonised classification according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation). Although it is well known, that this substance is acutely toxic. And is listed under the Kemi: PRIO Phase-Out Substances List. Alternative substance: The alternative zinc chloride is not listed in the SUBSPORTplus Database. » Check the Substance Database according to SUBSPORTplus Screening Criteria (SDSC)
Description of Substitution
Zinc and zinc alloy coatings are the most widely used electrolytic surface treatments, providing corrosion resistance and/or cheap decorative coating to a very wide variety of iron and steel items for the automotive, construction and other industries. An electroplating company got the idea to substitute zinc cyanide with zinc chloride from other companies where the process had already been implemented. The motivation to substitute was health and safety of employees, as well as environmental considerations. In addition, there is a regulatory requirement for phasing out hexavalent chrome (Cr6+), as well as emerging customer requirements concerning phasing out cyanide zinc. The workflow for the two methods differs, because the acid zinc method comprises significantly more process steps. Nevertheless, the time consumption for both processes is identical overall, since the cleaning step in the acid zinc method is more efficient. The new method provides at least the same quality as before or even improved quality. The costs for the new and old approach are the same. The company was able to keep the same chemical supplier and generally there has not been any disadvantage with the change in process.
Case/substitution evaluation
Zink cyanide poses a higher health hazard to employees as compared to zinc chloride because of its acute toxicity. The environmental hazard is identical for both chemicals. The two galvanic processes involve several more chemicals than zinc cyanide and zinc chloride. All components in the processes need to be taken into consideration. Zinc chloride was assessed against hazards in hazardous Substance Database according to SUBSPORT Screening Criteria (SDSC) and passed. This substitution needs to be improved as the alternatives contain still risks for human health.
State of implementation
Full capacity
Date and place of implementation
2011 Denmark
Enterprise using the alternative
Availability ofAlternative
Alternative is available on the market.
Type of information supplier
User
Further information
Information from the supplier SurTec: Product Overview Zinc Plating SurTec 758 BC Bright Acid Zinc Process Functional Electroplating https://www.surtec.com/en/applications-detail/83/ Decorative Electroplating https://www.surtec.com/en/applications-detail/84/ Background information on surface treatment of metals and plastics. The BAT (Best Available Techniques) Reference Document (BREF) entitled 'Surface. Treatment of Metals and Plastics (STM)' (2006) http://eippcb.jrc.ec.europa.eu/reference/BREF/stm_bref_0806.pdf.
Date, reviewed
December 11, 2020