When will copper contamination constrain global steel recycling?

Copper in steel causes metallurgical problems and cannot be removed from the melt. Globally trading scrap for use in tolerant applications and dilution with primary iron sources can manage contamination issues to an extent.... [ view full abstract ]

Copper in steel causes metallurgical problems and cannot be removed from the melt. Globally trading scrap for use in tolerant applications and dilution with primary iron sources can manage contamination issues to an extent. There exists no analysis of copper in the global steel cycle, so the long-term viability of this strategy cannot be known, but becomes important as available end-of-life scrap volumes significantly expand and demand needs shift. The copper concentration of flows along the 2008 steel supply chain, both expected and the maximum concentration tolerable, is estimated from a survey of literature data, while projections for final steel demand and scrap supply by sector are used to determine when the amount of copper in the system will exceed that which can be tolerated. It was found that copper quantities arising from conventional scrap preparation can be managed in the global steel system until 2040-2050, at which point interventions for reducing copper in the system will be necessary. Considering the recycling of end-of-life vehicles to applications such as reinforcing bar—and the resultant loss of alloying elements—provides motivation to close product loops before this constraining point is met, so technical and policy interventions along the supply chain are presented.