Material flow analysis of scarce metals: sources, functions, end-uses and aspects for future supply.

A number of metals that are now important to the electronic industry (and others) will become much more important in the future if current trends in technology continue. Most of these metals are byproducts (or hitch-hikers) of a small number of important industrial metals (attractors). By definition, the metals in the hitch-hiker group are not mined by themselves, and thus their production is limited by the demand for the major attractors. This article presents a material flow analysis (MFA) of the complex inter-relationships between these groups of metals. First, it surveys the main sources of geologically scarce (byproduct) metals currently considered critical by one or other of several recent studies. This is followed by a detailed survey of their major functions and the quantities contained in intermediate and end-products. The purpose is to identify the sectors and products where those metals are used and stocked and thus potentially available for future recycling. It concludes with a discussion of the limitations of possible substitution and barriers to recycling.

Material efficiency: rare and critical metals.

In the last few decades, progress in electronics, especially, has resulted in important new uses for a number of geologically rare metals, some of which were mere curiosities in the past. Most of them are not mined for their own sake (gold, the platinum group metals and the rare Earth elements are exceptions) but are found mainly in the ores of the major industrial metals, such as aluminium, copper, zinc and nickel. We call these major metals 'attractors' and the rare accompanying metals 'hitch-hikers'. The key implication is that rising prices do not necessarily call forth greater output because that would normally require greater output of the attractor metal. We trace the geological relationships and the functional uses of these metals. Some of these metals appear to be irreplaceable in the sense that there are no known substitutes for them in their current functional uses. Recycling is going to be increasingly important, notwithstanding a number of barriers.