“Dark green” and “bright green” defined

“Bright green” people believe an environmentally sustainable future can include many hi-tech gadgets for example; autonomous electric cars, smart phones and an “Internet of things” helping humans live more efficiently and reduce negative impacts on planet Earth.

“Dark green” people believe humans must change their behaviour to use much less energy and resources, and that we can have a happier healthier lifestyle if we live more in contact with nature. Not necessarily return to medieval living, we will keep some “smart” gadgets, electric vehicles, wind turbines and solar panels for example, but rather to live more slowly and buy much less stuff so we use less energy and resources.

So, although I’m a science nerd whose definitely in favour of wind turbines, solar panels and electric trains why am I a “dark green?”

Quick answer: we don’t have enough reserves of the necessary materials to make huge amounts of gadgets.

Detailed answer: get a copy of the “periodic table,” a web search will get one for you; let’s look at what planet Earth is made of and how much of it there is.

 

Chemistry crash course

Each box on the periodic table represents a chemical element. There are 103 named elements and a few that are only represented by numbers as they have not yet received names.

An element is something that we cannot make or destroy, and the whole universe is made up of just these elements. For example: carbon, number 6, symbol C, sodium, 11, Na, chlorine, 17, Cl and iron, 26, Fe are four elements. Mixing sodium and chlorine in the right proportion produces sodium chloride (common table salt), Mixing iron and carbon in the right proportion produces steel. However, we cannot make or destroy elements. If the universe is made up of just the elements on the periodic table, and we cannot make or destroy elements, it follows that all life on earth and humans’ economy is based on moving these elements around and making things.

Imagine an element as a certain kind of Lego brick. It is just like having one big box of assorted Lego bricks and using just the bricks in the box to build everything. If you run out of a certain kind of brick that is vital for you to build something, a long beam for a bridge for example, then you can’t build it.

Ninety two elements naturally occur on planet Earth and about twenty highly radioactive elements are created during nuclear reactions. Some of the naturally occurring elements, uranium, 92, U, radium, 88, Ra for example, are also radioactive. So we have about 80 non-radioactive elements (80 different kinds of Lego brick) from which to build everything.

 

Time to go mining

What is planet Earth made of?

Earth’s upper crust (the only bit of the planet we can conceivably mine) is mostly composed of just nine elements: 46 percent oxygen, 28 percent silicon, 8.2 percent aluminium, 5.6 percent iron, 4.2 percent calcium, 2.5 percent sodium, 2.4 percent magnesium, 2 percent potassium, 0.61 percent titanium, and 0.49 percent all other elements. I’ll reiterate this point, 99.51 percent of Earth’s upper crust, the only part that we could conceivably mine, is made up of just nine elements and all other elements combined account for 0.49 percent. This is why we make so much from iron and aluminium, and why clays and many rocks are silicates (compounds containing mostly silicon and oxygen).

Producing elements

Here I will discuss “producing” elements such as: tin and neodymium, but when I use the word “produce” I mean the process of mining ore out of the ground and refining it to separate out the desired element.

What are gadgets made of?

Smart phones, computers in their many forms and computerised electric cars like the Nissan Leaf are good examples of gadgets. Gadgets contain a quantity of around seventy different elements, and some of these elements, which are vital for the gadgets to work, are extremely rare and mining them causes serious environmental pollution.

 

Rare Earth Elements

Rare Earth Elements (REEs), a group of metals, were so named because they are (from an economic mining view point) rare. REEs generally do not occur in large ore deposits that can be mined; instead Rees are generally thinly spread throughout the Earth’s crust. In contrast, abundant metals such as aluminium and iron, and even much less abundant metals such as gold tend to become concentrated in large ore deposits that can be mined. It’s a lot more economical to dig one big hole through an ore deposit and extract the contents than to strip mine entire continents and process all the rock.

The only place where large ore deposits of REEs occur and can be economically mined is China. This is why China is the primary supplier of REEs to the global market.

Today the five most “gadget vital” REEs are: neodymium, samarium, terbium, dysprosium and yttrium.

Yttrium, 39, Y, when mixed with elements such as Terbium, 65, Tb and Europium, 63, Eu forms the coloured phosphors used in gadget display screens.

Yttrium is also used in jet engines and super conducting magnets for MRI scanners and Maglev trains.

Neodymium, 60, Nd, is used to make powerful neodymium iron boride magnets used in motors and generators. The motor of one “Toyota Prius” electric car contains one kilogram of neodymium.

Neodymium is the only “gadget vital” REE that might be economically possible to mine outside china. However, extracting and refining the ore is still likely to cause environmental pollutants which will need to be treated.

“Siemens,” who manufacture wind turbines, plan to source all the neodymium that they need for generator magnets from mines outside China.

Dysprosium, 66, Dy, used in computer data storage and in neodymium magnets. Due to the increasing numbers of magnets being manufactured for electric cars and wind turbines the cost of dysprosium is increasing. “Siemens” are working on Neodymium magnets so that they don’t require any dysprosium. “Toyota” is replacing dysprosium in magnets with the elements; lanthanum, 57, La and cerium, 58, Ce. How long before the increasing demand for La and Ce also out strips their supply?

Lanthanum, 57, La, uses include: batteries (the nickel metal hydride batteries of one “Toyota Prius” contain around 12 kg of lanthanum), catalysts, magnets and fibre optics.

Samarium, 62, Sm, when combined with cobalt, 27, Co, produces very tough and powerful magnets.

Cerium, 58, Ce, uses include: LED lights, catalytic converters, magnets.

Cobalt, 27, Co, uses include: batteries, magnets, industrial cutting tools and catalysts.

Around half of all the cobalt that is produced globally is used in lithium batteries. Due to the increasing demand for lithium batteries the global production rate of cobalt has doubled in the last ten years.

Tantalum, 73, Ta, used to make capacitors for gadgets.

Tungsten, 74, W, uses include: X-ray machines and industrial cutting tools.

Tin, 50, Sn, tin based solders join electronic circuits together. Indium tin oxide is transparent and conductive, it is used to make gadget display screens. Tin is also used in the “float glass process” producing large amounts of low cost sheet glass.

Other elements vital for semiconductors, computers, LED lights and photovoltaic cells include: gallium, 31, Ga; germanium, 32, GE; arsenic, 33, As; selenium, 34, Se; cadmium, 48, Cd; indium, 49, In and tellurium, 52, Te.

 

Unplanned production

Many elements are not deliberately mined for themselves; they are produced as by products of the production process of another element. For example the elements listed just above from gallium to tellurium are produced as by products in the production of another metal, often zinc. So the rate of zinc production governs the rate at which many other elements are produced.

 

Unplanned shortages

If an element is only produced as a by-product during the production of another primary element, it is possible to run short of the by-product element if demand for the primary element decreases.

Hafnium, 72, Hf, was produced as a by-product during the difficult and expensive separation of hafnium from zirconium, 40, Zr. Pure zirconium is used to make nuclear fuel rod casings. Unwanted hafnium was used in electronics, jet and rocket engines. However, after the accident at the Fukushima Daiichi nuclear power station and the resultant closure of many nuclear power stations there is little demand for pure zirconium. So the production of hafnium has stopped and it has become very scarce. Total global supply of hafnium is 50 tonnes and this has to last the jet engine industry.

 

Labour force and pollution

More than half of the world’s cobalt is mined in Congo.

Cobalt, gold, tantalum, Tin and tungsten were some of the “conflict elements” mined and sold by Congo and Rwanda to fund their wars.

One third of global tin production occurs in strip mines on two Indonesian islands where the deforestation, soil erosion and pollution have wrecked the local environment and fishing economy.

Rare Earth Elements in Chinese mines are usually found mixed together along with the radioactive element thorium. Separating them to produce the different REE elements is expensive and polluting, the land left behind is toxic, radioactive, crops do not grow, teeth fall out, cancer, etc.

Mining in many countries is not as “safe and clean” as we would insist if the mining occurred in Europe. No regulations govern environmental pollution or mine safety so cave-ins and deaths are frequent; however, mining is the only paying job to buy food so children and adults continue to mine regardless.

 

Circular economy

Recycling gadgets is difficult. For example LED lights contain various metals: nickel, indium, gallium, lead, arsenic and REEs. Once LEDs are sealed in glass and plastic it is difficult to dismantle and recycle them. The only ways to dismantle a LED are to: smash, grind, dissolve or burn it, so the constituent elements can be extracted.

Recycling computer chips is just as difficult as recycling LEDs.

 

Conclusion

This is why I’m a “dark green.” If we’re going to mine elements then we should make the very best use of the end products for as long as possible, and not design stuff that we don’t need.

 

Comments

 

Dr Owen, Centre for Alternative Technology:

I am in a similar camp even though I’m an engineer, and have long recognised the problem that you outline (but lacked the detail that you have given). I also worked in Indonesia for 6 years and have seen a lot of the misery and degradation that goes into making our stuff.

Dr Watson, Centre for Alternative Technology:

The document is key to an argument for a circular economy. As a chemist I feel we’ve still got a long way to go but managing the Rare Earth Elements will become an issue and I suspect a ‘peak oil’ type discussion will arise sometime in future.

 

– Dr Duncan Bell, August 2019