Recycling rates of metals: A status report
The recycling of metals is widely viewed as a fruitful sustainability strategy, but little information is available on the degree to which recycling is actually taking place. This report provides an overview on the current knowledge of recycling rates for sixty metals. We propose various recycling metrics, discuss relevant aspects of the recycling of different metals, and present current esti- mates on global end-of-life recycling rates (EOL-RR) [i. e., the percentage of a metal in discards that is actually recycled], recycled content (RC), and old scrap ratios (OSR) [i. e., the share of old scrap in the total scrap flow]. Because of increases in metal use over time and long metal in-use lifetimes, many RC values are low and will remain so for the foreseeable future. Because of relatively low efficiencies in the collection and processing of most metal-bearing discarded products, inherent limitations in recycling processes, and because primary material is often relatively abundant and low-cost (thereby keeping down the price of scrap), many EOL-RRs are very low: for only eighteen metals (aluminium, cobalt, chromium, copper, gold, iron, lead, manganese, niobium, nickel, palladium, platinum, rhenium, rho- dium, silver, tin, titanium, and zinc) is the very important EOL-RR above 50 % at present. Only for niobium, lead, and ruthenium is the RC above 50 %, although sixteen metals are in the 25 – 50 % range. Thirteen metals have an OSR > 50 %. These estimates may be used to assess whether recycling efficiencies can be improved, which metric could best encourage improved effectiveness in recycling and to provide an improved understanding of the dependence of recycling on economics, technology, and other factors.