Materials

When people think about resource limitations they rarely think about materials.  However, not everyone has ignored this issue.  A few years ago my parent’s church was plagued by thefts of lead from its roof.  After several such raids the churches insurer’s were getting jumpy and threats of premiums going up were made.  The church came up with a solution.  That was pay a Venture Scout to sit up the church tower with a mobile phone.  He didn’t have to long to wait.  One night dozens of police turned up with dogs and caught the thief.  Now they have made a series of security measures that don’t involve venture scouts.  Church roofs were a real problem for thefts, but not the only one relating to materials.  Thefts of copper were also a huge problem from railway lines meaning a huge number of passenger delays.

Since then the problem has eased in the UK for two reasons firstly metal prices have fallen and second the government has made it illegal to sell metals without proof of ownership.  Nevertheless a number of issues related to materials do still present themselves and were covered in an article in New Scientist (14th Feb 2015). These are;

  • The energy used to extract them.
  • The damage made doing so.
  • Where they come from.
  • How much of them is left and the ore strength.
  • How much they can and are recycled.
  • substituablity (will something else do for a particular use).

The table below gives some uses for some materials.

Material Use
Copper wiring
Platinum Catalytic converters/catalysts/anti-cancer drugs
Indium Touchscreens/solar PV
Cobalt batteries/machine tools
Neodymium magnets in electric cars and wind turbines
Silver solar PV
 Gallium mobile phones
 Germanium Camera lenses

Looking at energy of extraction and processing materials vary greatly.  The picture of the periodic table below gives two examples for copper and ruthenium with their recycling rates.  Looking at the energy cost, the figures are vastly different.  But this is of course not the whole story.  The amount of copper mined is much greater than that of ruthenium.  Therefore the amount of energy required for copper production is vast (1).  As we covered in our book it could mean as ore strength falls the quantity of energy used for copper extraction alone could be 30% of all the energy used in the future.

Periodic Table_opt

One apparently simple solution is to recycle.  With something like copper, recycling is easy.  Its used in large quantities and we can generally see it as copper pipes or something tangible.  Recycling for lead copper, zinc and aluminium are all above 50%.  In the case of mobile phones (vast numbers of which are disposed of every year) you would be barely able to see the “rare earths” used and these are therefore very difficult to recycle.  Recycling rates for these are below 1%.

How much of these materials are left is another hotly disputed question.  Rare earth reserves are said in this article to be worrying, but platinum OK.  There has however been research done on collecting the tiny amounts of platinum excreted by catalytic converters in vehicles that end up on the street using bacteria.  This suggests stocks are not so good.

Substituting one material for another is theoretically possible.  Its easier with mainstream materials such as lead or copper, but less easy with some of the rare materials.  Surprisingly these hi-tech industries can be conservative though.  A doctoral student at my university was doing research into using brass as the aerial in mobile phones rather than tungsten, tantalum and cobalt.  She said it works and would avoid the ethical dilemmas associated with materials from conflict zones.  To the best of my knowledge no phone uses this technology.

I have only covered a few of the issues in the area of materials.  I would encourage you send your phone or other electronic devices for recycling (despite what I wrote above) as well as other materials.  There is in any case a contamination problem if these devices end up in landfill.  If you buy a new one why not consider the worlds only fairly traded electronic device.  Also Greg Valerio has set up a fair trade scheme for gold (as jewellery).  Both try to avoid using materials from conflict zones.  We need to substitute as far as possible with simple recyclable materials and build recycling in.

1) Nuss P, Eckelman MJ (2014) Life Cycle Assessment of Metals: A Scientific Synthesis. PLoS ONE 9(7): e101298. doi:10.1371/journal.pone.0101298

Neil

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