TA11A Case Studies on Minerals and Metals Products
C120-122
8:00 AM - 12:00 PM, Tuesday
() IO MFA Analysis of the Relationship between Cadmium Recycling and Zinc Production.
Hawkins, T.1, Matthews, H.1, 1 Carnegie Mellon University, Pittsburgh, PA, USA
ABSTRACT- Minimizing environmental releases of cadmium has been the focus of numerous policy decisions made by western nations because of its toxicity. Cadmium is bioaccumulative, replacing the mineral zinc in plant and animal tissues readily. Exposure to elevated levels of cadmium is known to cause serious human health effects such as lung, kidney and liver malfunction, bone decalcification, and prostate cancer. Over 11,000 tonnes of cadmium are contained in products entering the U.S. market annually. Nickel-cadmium batteries account for the majority of this cadmium with pigments, metal coatings and platings, and plastic stabilizers making up most of the difference. Although efforts are being made to minimize the end of life cadmium waste entering the environment, currently only 15% of cadmium scrap in the U.S. is recycled. Incentives for returning spent NiCd batteries and extended producer responsibility might provide effective means of increasing the recycling rate. Such programs have been successful in Germany and other EU countries. Modifying battery packaging to improve ease of disassembly and to provide information about the contents of the battery would aid in reducing the costs of recycling NiCd batteries. In this analysis an input-output material flow model is used to examine the impact of increasing secondary cadmium production on the anthropogenic flow and environmental release of cadmium. Primary cadmium is obtained as a byproduct of primary zinc. Assuming worldwide demand for zinc continues to increase, stepping up secondary cadmium production will result in additional cadmium disposed of as mining wastes unless the recycling rate of zinc is increased accordingly. This analysis will examine the role played by both zinc and cadmium in the risk-reduction potential of cadmium recycling. The tradeoff between the relative risk associated with the resulting volume, composition and distribution of the cadmium waste from primary and secondary production will be considered in this analysis.
Key words: Cadmium, Material Flow Analysis, Zinc