Copper alloy scrap is a very significant factor in making the United States self sufficient in its overall consumption vs. production of copper. In 1995, U.S. mine production was 2,050.3 thousand short tons; 1,673.9 thousand short tons of copper in domestic scrap entered the stream giving a total copper consumption of 3,724.2 thousand short tons. Scrap provided 44.4% of the total copper consumed. As shown below, scrap consumption over the past 20 years has provided between 44 and 54.7% of the total copper consumed in the U.S. The intrinsic value of copper scrap drives this process. No. 1 copper scrap commands over 90% of the price of new refined copper.
Copper scrap in the United States is very roughly half prompt, or new manufacturing scrap, and half old post-consumer scrap. This is low velocity material with product life of 10 to 100 years or more. The trend had been toward more old scrap and less new. New scrap has decreased from 61% to about 54% of the total U.S. scrap recycled in 1992, but has bounced back up to 61% in 1995. The graph below shows these trends.
Most scrap, 67.4% in 1995, is remelted directly by brass mills, wire rod producers, foundries and ingot producers. As shown on the flow diagram below, the remainder goes back into the stream at the smelting and refining stages. Of the 1,105,600 short tons of scrap that goes to alloy production, about 22.5% goes to the ingot producers and foundries for cast copper alloy products, and 68.9%, or 762,100 short tons, to the brass mills. Consumption of copper scrap for alloys has grown by over 50% in 20 years. Increased consumption by brass mills accounts for virtually all of the additional scrap consumed. Scrap going for cast products has remained essentially the same; copper alloy cast products have not kept pace with the growth rate pace set by the brass mills.
Ingot producers and large captive foundries have traditionally been large consumers of used copper/brass automotive radiators. This material provides copper, zinc, tin and lead units and has been ideal for production of the approximately 100,000 short tons of red and semi-red brass alloy ingot produced. About half of this is used for plumbing products in the U.S., a distinctly different picture than that in Europe where yellow brass predominates in plumbing products. The radiator to red brass transformation has been an economically driven and environmentally sound recycling of valuable materials. No detailed statistics on the contribution that radiator scrap makes to the 250,000 tons of scrap consumed for cast products exist, but discussion with ingot manufacturers indicates that radiators have accounted for about 50% of the charge in the production of the red and semi-red brass alloys. About 50,000 tons of radiators per year are melted by the ingot producers. The plumbing alloys themselves, as both post consumer product and prompt returns, have been a significant contribution to the ingot producers' incoming material. Both of these types of scrap in terms of the amounts available and their compositions are now undergoing a gradual transition in the U.S. The forces responsible for the transitions in auto radiator and plumbing materials are very different.