Waste in a manger: a materials nativity

by Steve Watson

No nativity scene or play is complete without the presence of the Magi bearing their gifts of gold, frankincense and myrrh to the new born messiah. Despite their ubiquity in our picture of Christmas, little is told of them in the Bible except that they travelled from the East following a star, and they are traditionally thought of as wise men or kings.

What, however, if the Balthezar, Caspar and Melchior had been secondary materials specialists, waste industry leaders, or directors of environmental consultancies? If they had come to worship the Christ child with their greatest treasures, what precious gifts might they have brought? What are the most valuable secondary materials, and in what does their value lie?

Alu-lujah

If the Magi’s interests had lain more with resource management than with astronomy, they may well have chosen aluminium over gold. Aluminium commands the highest material price out of the standard range of household recyclables, with baled cans currently fetching upwards of £700­ per tonne on the secondary materials market. Prices are even higher for aluminium recovered from industrial manufacture, with pure cuttings fetching over £1,000 a tonne in some cases.

This isn’t because primary aluminium is scarce: it’s the third most common element in the Earth’s crust after oxygen and silicon. However, only occurs in compounds – primarily bauxite – from which its extraction is energy intensive, polluting, and expensive. The process involves generating temperatures of around 960°C and electrolytic reduction; according to the Department of Business Skills and Innovation (BIS), electricity costs make up over 50% of GVA for the UK aluminium industry.

It is clear then why there is a demand and a high price for readymade, secondary aluminium. The energy expended in primary production remains embodied in the scrap, meaning that the value of a bale of aluminium cans also reflects the costs of that energy. Furthermore, as the metal’s atomic structure is not altered when melted, scrap is useful for most of the same applications as virgin material.

The industrial demands of primary aluminium production don’t just give its secondary form high economic value, but also high environmental value. The Global Aluminium Recycling Committee (GARC) has claimed that recycling aluminium uses 5% of the energy and emits 5% of the greenhouse gases of primary production. Aluminium cans and foil also sit at the top of the Scottish Government’s Carbon Metric, which uses a life cycle approach to calculate the carbon savings of recycling a range of materials. The latest metric figures tell us that 9,267 kgCO₂eq is saved for every tonne of aluminium cans and foil recycled.

Economic and environmental value are in this case closely linked. You don’t have to be a magus to grasp that what makes aluminium production bad for the environment also makes it expensive.

Vintage robe store

When the Carbon Metric was originally released in March 2011 textiles rather than aluminium topped the carbon savings league table. However, when a set of revised factors was published a year later textiles had dropped to 15^th place (at a saving of 1,102 kgCO₂eq per tonne recycled) with the caveat that this covered ‘recycling only’. The original calculations presumably included the carbon savings resulting from textile reuse. This raises an important point: the greatest environmental benefits from secondary textiles are delivered through preparation for reuse rather than recycling processes.

The average batch of clothes deposited at a clothing bank bin contains a mixture of the desirable, undesirable, and practically unwearable. High value items such as suits will be pulled out for onwards sale through second hand stores, while lower grade clothing may be shipped for reuse overseas. Lastly, those items incapable of being worn are unspun and their fibres used to produce new items of clothing.

As with aluminium, the key is embodied energy. Consider a magus’s cotton robe: this item embodies all the energy needed to grow the cotton crop, spin the cotton into thread, weave the robe, and finally fashion it into a state fit for a king with dyes and adornments. At least the carbon costs from transport would be relatively small for a modern wise man’s robe, assuming it was procured locally in the orient, since most textile manufacture occurs in the East.

Touched by your presents: what gifts would the wise men of waste management bring? Photo by Nina Aldin Thune, via Wikimedia Commons.

A Christmas gift of textiles draws the giver into the strange market dynamics governing the global flow of clothes. High street clothing is generally manufactured at low cost, with cheap labour in countries such as India. It is then imported to the West for consumption before entering – if it’s lucky and doesn’t end up in a landfill or incinerator – the second hand market. Then, if it isn’t desirable enough for re-sale in the West, it may well be shipped for re-sale to developing countries, where there is a huge market for cheap clothing. India is one of the few developing countries to implement a duty on the import of second hand clothing, with the aim of supporting the textile industry that forms some 7% of the country’s industrial production. Developing countries with less economic clout and less of a history of textile production find it difficult, however, to prevent their markets being flooded with first world cast-offs.

Textile prices in the UK have been driven up by the export market, in conjunction with a growing domestic appetite for ‘vintage’ clothing. At present, material from textile banks – which is more likely to be low grade or contaminated, and therefore exported – is currently valued at between £235 and £295 a tonne. The higher grade items donated to charity shops are currently valued at on average £325 to £345 a tonne. These high prices have led to the proliferation of ‘weigh in’ clothes stores, where old items can be exchanged for cash. They have even led to textile-centred waste crime, such as theft of textiles from kerbside containers – hardly the ideal way for a wise man to obtain a gift.

While textile reuse certainly has significant environmental benefits, a magus might well wonder at the wisdom of the economic relationships driving textile prices.

WEEE three kings

An iPhone doesn’t contain frankincense or myrrh, but you will find gold in it. And silver. And copper and platinum, alongside a host of rare earth minerals such neodymium, yttrium and lanthanum. It’s not just Apple products that contain these materials: most of the small WEEE items that will be given as gifts this Christmas are veritable miniature treasure troves of precious minerals.

That gold and silver have financial value will be no surprise, but what about the rare earths? These minerals are not – as their name would suggest – in fact rare, but are fairly abundant in the Earth’s crust; however, they generally occur in very small amounts, making their extraction labour and cost intensive. What’s more, there are currently no productive rare earth mines in Europe or America, with China being by far the global leader in terms of production. Recovery of rare earths should have strategic value in terms of market competitiveness for Western nations, in addition to their immediate financial value, and you would therefore expect to see a lot of recycling going on. Unfortunately, however, rare earths are almost as difficult to extract from computers as they are from the ground.

Historically, small WEEE recycling has focussed on extracting components with obviously high material value: gold, silver, copper and the like. Rare earth extraction methods are therefore somewhat behind, but recycling is also difficult simply because rare earths are used in such small amounts, within internal components that are often fused together in the manufacturing process. Dismantling is tricky, and so a lot of it occurs by hand, overseas, after export. However, even if only the obviously valuable metals were extracted domestically, the financial rewards would be high, and one would expect to see more small WEEE collection occurring than actually does.

What of the environmental value? Small WEEE sits in 7^th place on the Scottish Government’s Carbon Metric at a saving of 1,482 kgCO₂eq per tonne recycled. No doubt many factors play into this calculation, but a non-carbon consideration is worth mentioning. One reason why China has so far dominated global production of rare earths is because its environmental restrictions on mining are low. Just as with bauxite, mining rare earths generates a lot of pollution, and recycling these materials is one way to lessen the impact.

So, the choices for our modern waste Magi are clear: the three most valuable materials on today’s secondary materials market are aluminium, textiles, and small WEEE. Their value is derived from different market forces, and the systems in place for the recovery of some are far more advanced than others. However, each illustrates the link between economic and environmental costs, driven by the value of preserving embodied energy. The lesson of our waste nativity is that often environmental and cost savings go hand in hand, wisdom befitting a magus.

Steve Watson