Metals are not biodegradable, have a virtually unlimited lifespan, and can be recycled almost without limit, CSIRO's Dr John Rankin and Dr Terry Norgate told the Green Processing 2002 Conference in Cairns today.
Mineral resources are finite, but metals can in theory go on being re-used countless times, with huge savings in energy and reduction in the waste involved in primary processing.
The "ecological footprint" of the human race was estimated in 1997 to be nearly a third larger than the earth's total biological capacity, and by 2030 this could rise as high as 130 per cent, emphasising the importance of making better use of the resources we already have, they said.
"One way to do this is by 'dematerialisation' – reducing the amount of energy and materials you need to produce goods or services. Metals are particularly suited to this, as they have the greatest potential for unlimited recycling."
"However, recycling alone cannot meet the increasing need for metals, and fresh metal and minerals will be required for many generations to come" says Dr Rankin.
Lifecycle analyses of key metals by CSIRO from mining to the point of manufacture has shown that there is significant scope for savings in energy, global warming potential and acid pollution in their production, Dr Rankin said.
Another issue is that declining ore grades are slowly pushing up the amount of energy required to produce a tonne of metal.
New technologies are needed to dramatically reduce the environmental impact of minerals and metals production from ores. Australia, with a large and technologically advanced minerals industry and strong R&D capability in the area, is well placed to become a world leader in the development and implementation of "green" processing technologies.
Dr Rankin says the advent of a carbon tax would have a major effect on metals production, with greater emphasis on low energy extraction processes, and a greater emphasis on recycling.
"Despite earlier concerns about possible shortages, there are no indications that metals scarcity will be a major problem for future generations.
"However increased energy consumption associated with decreasing ore grades and the likely introduction of carbon or energy taxes will place more emphasis on recycling in future, and greater efforts to redesign the supply-chain to remove energy-intensive steps in primary metal production.
"It is also possible that low-energy intensive metals like steel may replace high-energy metals (eg aluminium) in applications where weight is not especially critical, and vice versa."
"Of all the materials used by society metals have the greatest potential for unlimited recycling.
"They offer the ability to conserve resources, reduce energy use and minimize waste disposal."
For detailed information on the program:
Conference website:
http://www.ausimm.com.au/green2002/html/program.html