Analysis of copper flows in the United States: 1975–2012

•The U.S. abandoned old scrap and exchanged it for copper resource through trade.•The share of refinery scrap in total refined copper decreased due to environmental pressure and cheap primary production.•The concentration of top six importing scrap countries increased to 90% and China is the destination of 70% scrap in recent years.•All scrap into manufacture stage accounts 90% of all domestic use scrap for classification of scrap and environmental and economic pressure.

Under the framework of a four-stage substance flow analysis, this paper displayed a quantified picture of copper flows in the U.S. in several specific years from 1975 to 2012. The ratio among the output of refinery and manufacture has changed from 0.30, 0.36, 0.34 in 1975–0.30, 0.25, 0.45 in 2012. It shows that production shrinks and manufacture increases. Domestic recovered old scrap in 2012 is 3 times as much as that in 1975. However, the use of old scrap in 2012 is only 40% of that in 1975. Meanwhile, the U.S changed from a net exporter (27.5 Gg) in 1975 to a net importer (471 Gg) for refined copper. All these results showed that the U.S chose importing refined copper to satisfy the demand rather than recycling old scrap. Because the U.S tend to acquire copper resource in a more ecological and economic way. Due to economic and environmental pressure, the production stage prefers low-priced primary production rather than secondary production. Most old scrap is transferred to other countries and China became the destination of more than 70% scrap. Only pure or clearly graded scrap is recycled for domestic use and the majority is directly used in manufacture stage.