Material World: The Six Raw Materials That Shape Modern Civilization

by Ed Conway

All you need in one of these fabs is for a single stray atom to float into the machinery and thousands of dollars’ worth of transistors will be instantly ruined. If all goes to plan, our silicon wafer will not be touched by a single human hand until its surface is sealed up and it is ready for dispatch.

How on earth can one physically beam that kind of detail down on to a chip the size of a few centimetres? With one of the most expensive machines in the world. The TWINSCAN NXE:3600D—made by ASML, a Dutch business which used to be part of Philips—costs hundreds of millions of dollars. That might sound excessive, given it is ultimately just bouncing light around a box, but this is no ordinary light and no ordinary box. After all, recall that the transistors TSMC wants to make are so small they are quite literally invisible, so a conventional wavelength laser and a series of lenses will no longer do. In order to get the finest of all resolutions you need light with the smallest of all wavelengths, which in this case means extreme ultraviolet (EUV) light.

In a vacuum chamber inside this machine, tin is melted until it becomes a liquid. That molten tin is then dropped down into the chamber in a continuous stream. In the midway point of their cascade, each of these tiny droplets is zapped twice by pulse lasers, provided by German company Trumpf, which are powerful enough to cut through metal. These bursts heat the tin up to a million degrees, transforming it into a kind of plasma that simultaneously creates a burst of EUV light. This pinpoint smashing of molecules happens 50,000 times per second, so fast that the stream of tin droplets and the laser explosions are totally indiscernible. All of this to generate a stream of EUV light whose real task is yet to come, for only then is it bounced out towards our waiting wafer.

in order to bounce this EUV light down on to the wafer, ASML has contracted Zeiss to produce a set of special mirrors called Bragg reflectors, made from layers of silicon and molybdenum. Quite how these mirrors are made is yet another closely guarded trade secret, but according to Zeiss, they are ground down from blocks weighing 50 kilograms, and robots are used to polish and correct the outer layer with ion beams. Suffice it to say, they are, according to one ASML engineer, “probably the smoothest man-made structures in the universe.” If you blew one of them up to the size of the United States, the biggest bump would be less than half a millimetre high.

Having bounced off a staircase of these mirrors, the EUV light in all its 13.5 nanometre glory hits the wafer and etches that intricate design on to it.

Even if China invaded Taiwan and even if TSMC’s fabs survived the assault (some have suggested that the company incorporates explosives into the foundations, to be detonated upon invasion much as armies destroy bridges before retreating), that would not resolve its issue. Fab 18 might be where the world’s most advanced chips are made, but they are mostly designed elsewhere, primarily in the U.S., with intellectual property that derives from a company based in Cambridge, England: ARM. TSMC’s fabs would not function without machine tools from the Netherlands and Japan, or chemicals from Germany and bits and pieces from a range of other nations. There is only a handful of companies capable of making perfect silicon wafers, and none is headquartered in either the U.S. or China. And there is only one site in the world capable of making the quartz sand for the crucibles where those wafers are crystallised.

Historians have long theorised that the reason much of human civilisation began on coastlines was because of easy access to salt.

The third and final way to produce salt is to extract it from the ground in the form of brine—a saline solution that is more than 30 per cent salt, as opposed to the 3 per cent of seawater. This is called “solution mining” and in a sense it’s not so different from digging it out physically: you are still mining the same seam, only solution miners use remote hoses of pressurised water rather than drills and dynamite. Solution mining, surreal as it sounds, is one of the main ways we get salt these days, at least in those parts of the world without enough heat and sunlight to evaporate seawater.

Much of America’s salt comes from underground in Kansas, Louisiana, Texas and New York state. Morton, one of the most famous producers, makes salt in Rittman, Ohio, and Silver Springs, New York, but as solution mines, they are essentially invisible. All there is to see at ground level are a few pipes, pumping down water and pressurised air, and pumping up salty brine.

Over time the -wich suffix in a town’s name came to denote saltworking.

today salt is the bedrock for the chemicals and pharmaceuticals industry. While a fraction of the brine pumped out from under the ground here in Cheshire gets turned into table salt, the majority is piped up to factories where it is turned into products that quite literally keep us alive.

One consequence is that hardly anyone has ever heard of the chloralkali process, which is a shame because it is one of the most important industrial achievements of the modern age. Here’s how it works. Brine is pumped out of the fields in Cheshire and piped up to a plant in Runcorn, which used to be part of Imperial Chemical Industries (ICI) but is today owned by another firm, Inovyn, part of Ineos. There on the banks of the Manchester Ship Canal, the brine is piped into a room full of hundreds of electrolysis cells, where a strong current is run through it. The scale of power you need for an operation like this is mind-boggling. This single room of electrolysis cells consumes more electricity than the city of Liverpool. It also creates such an enormous magnetic field that anyone with a pacemaker is not allowed anywhere near the building. Yet the funny thing about electromagnetic power is that the human body can’t detect it. I stood there in the middle of the dusty cell room at Runcorn, being exposed to the strongest magnetic field anywhere in the country, yet I felt…nothing. Right next to me, beyond a flimsy Perspex screen, this electrical current was tearing the brine apart, atom by atom. There was a low hum and the sound of sloshing liquid as out of one electrode came a yellow cocktail of chlorine gas and some brine; out of the other came hydrogen gas and sodium hydroxide, better known as caustic soda. These substances, humdrum as they may sound, are among the most impo...

Consider the story of soda ash, that chemical used as a flux in glassmaking since the dawn of civilisation. This extraordinary alkali can help reduce the melting point of silica sand when added in a furnace. When mixed with oils and fats it can create soaps and it’s also instrumental in the production of paper. You will rarely go a day of your life without touching something that owes its existence to soda ash. Yet up until the industrial

Look at the map of the world’s pharmaceuticals and chemicals companies, and you see that we are still following ancient salt routes.

It is not for nothing that American chemicals giant Dow is headquartered in Michigan, above those deep rock-salt formations that sit beneath Detroit. As the trucks come and go with chemicals and pharmaceuticals, they are essentially retracing the same ancient salt routes as our ancestors.

A project is underway to carve much of the world’s most important knowledge on to stone tablets and deposit them in the Hallein salt mine in Austria, alongside the remains of those ancient Celtic miners.

was into similar salt caverns that most of Europe’s emergency gas was pumped after Russia invaded Ukraine in 2022, to be stored there as a kind of energy bank to get the continent through winter without gas from Siberia. America’s Department of Energy has a Strategic Petroleum Reserve, which keeps crude oil in old subterranean salt chambers in Texas and Louisiana. And such places are already being readied for a new future, where they can be used to store carbon dioxide captured from the environment and sequestered underground to reduce atmospheric greenhouse gases. These are the places where we will keep the green fuels like hydrogen, created from solar and wind power. In much the same way as the world’s chemicals industry is, often quite literally, built atop halite, tomorrow’s green energy industry will cluster around salt deposits. In salt we trust.

Mix this salt with a tiny fraction of sulphur and charcoal dust and you have gunpowder. But the problem with saltpetre was that for most of history it was frustratingly difficult to find. For hundreds of years, the main source was fetid organic matter, most notably rotting meat and urine. For a while military leaders of the time were disproportionately concerned with dung heaps and old, abandoned privies. Men were dispatched around medieval kingdoms on the hunt for patches of putrid earth. Having identified and tasted a patch for quality, they would dig up the stinking ground, boil it, strain it and evaporate it to produce precious flakes of saltpetre. If you do a job you don’t much enjoy, you can always console yourself that you were not one of these dung collectors—petermen as they called them in England—who had to contend not merely with a disgusting living, but also with near universal unpopularity.

When large deposits were discovered in the muds of India’s River Ganges it precipitated the country’s occupation. Within a few decades saltpetre became one of the most important items traded by the British East India Company.

The Chincha Islands are a grey set of rocks inhabited mostly by flocks of boobies, cormorants and penguins. Over thousands of years the birds’ droppings had accumulated into a bouncy crust more than a hundred feet deep. This was, it turns out, one of the finest natural fertilisers the world has ever known: a rich combination of phosphates and nitrogen compounds.

atmospheric nitrogen exists in the form of two atoms fused together in an incredibly tight bond; breaking these atoms apart and forming them into other nitrogen compounds we can use—“fixing,” as it’s usually called—involves phenomenal amounts of heat and energy. This also, by the way, helps explain why fixed nitrogen is at the heart of most explosives: just as it takes a lot of energy to break that atmospheric nitrogen apart, you generate a lot of energy when you put it back together.

For most of our existence the only way of fixing nitrogen from the atmosphere was to hope for a lightning strike or to wait months for the bacteria in certain plants to do it. Saltpetre represented a valuable shortcut, as did manures and compost, both of which are rich in nitrogen, albeit less rich than the fossilised bird droppings of the Chincha Islands. For years the Incas had collected this smelly earth—huanu as they called it—and ground it into a dust they sprinkled on to their fields. In recognition of the miracle they made the Chinchas holy islands, where killing a bird was a capital offence. When the Spanish conquistadores arrived and laid waste to what is now Peru, they paid surprisingly little attention to guano, as it became known, even though it was viewed by the Incas as being as precious as gold. But when the British

In January 1881 Chilean forces occupied Lima; by 1884 they had signed truces with Bolivia and Peru and took a vast swathe of territory to their north, including Antofagasta, all of Bolivia’s coastline and a large chunk of Peru’s caliche zone. It is hard to think of many other wars with a more consequential result than this. Chile won control of some of the most important mineral resources in the world—not just the nitrates of the Atacama, but the world’s biggest reserves of copper and lithium. This conflict turned the country into a resources superpower, depriving Bolivia of its coastline in the process.

In the following years Chilean nitrates helped feed and arm the world. It was Chilean nitrates in the Allied explosives that rained down on the trenches in the First World War. Their revenues helped finance the construction of more roads and railroads, electrical networks and plumbing, and helped Chile build an advanced military and attain the twentieth-century trappings enjoyed by many European countries. Thanks to this white salt, Chile became the richest nation in Latin America.

By 1913 BASF, the company Bosch worked for and eventually led, had begun to manufacture ammonia—that nitrogen/hydrogen compound which could then be converted into fertilisers and used to make explosives—in their plant at Oppau.[5] The Haber–Bosch process, as it has become known, is one of the most important scientific and industrial discoveries in history. It has, in the subsequent century, helped us to feed billions of people. One of the greatest triumphs of humankind during the twentieth century was banishing hunger and famine as a widespread issue.

The share of undernourished people around the world fell from around 65 per cent in 1950 to under 10 per cent by 2010—in large part because of the increased crop yields brought about by cheap, widespread fertilisers.

They are so widely used today that it is estimated that around half of the nitrogen in our bodies was fixed from the...

Were it not for these chemicals, we would have to turn over pretty much every square mile of land on the planet to agricultural production, covering it with manure from an equally enormous stable of animals, and even then we would still only be able to support roughly half the world’s population. But in those earliest years...

Roughly half of the nitrogen scattered and sprayed on to our fields has ended up not in our crops but in our air and our water. It has dissolved into the earth and thence into streams and rivers, where it has fuelled giant algal blooms which suffocate other aquatic life.

Between 5 and 6 million years ago—long after that meteor crashed into the Great Sand Sea but long before the arrival of Homo sapiens—the Med was cut off from the Atlantic and over hundreds of thousands of years it dried out almost completely, coming to resemble a giant version of today’s Dead Sea. The Strait of Gibraltar eventually reopened and, in what must have been the most extraordinary sight, the Atlantic suddenly gushed back through in a monumental tidal wave. While it is hard to imagine witnessing such a thing today, you can at least feel, or rather taste, the legacy, for the waters of the Mediterranean are still unusually salty, with about 38 parts per thousand of salt compared with 35ppt on average in other oceans. As Eurasia continues to collide with Africa, geologists expect that in the coming millions of years the strait will close again, this time permanently. The Mediterranean will eventually dry up and disappear altogether, leaving a layer of buried salts in its wake, much like the Zechstein Sea.[1]

Phosphorus comes primarily from the mining of phosphate rocks, most of which are to be found in Florida and Idaho in the U.S., as well as China and Morocco, the latter of which has nearly three-quarters of the world’s total reserves.

The potash business is an obscure and opaque one. Just as there is an oil cartel, OPEC, there is also a potash cartel, with producers aiming, a little like the salt makers of Victorian Cheshire, to control production and prices to keep themselves in the black. When Russia invaded Ukraine in 2022, one consequence was a sudden global shortage of fertiliser, since Russia and its ally Belarus provided roughly a quarter of the world’s potash. There, as here, the sylvite is found among the salt of buried seas: the Pripyat basin in Belarus and the Solikamsk basin in Russia.

It was an early December day, winter storm Barra was battering the north of England and all of a sudden it felt almost inconceivable that at this very moment there were miners sweating deep under the North Sea in temperatures hotter than a desert to extract a rock most people have never heard of before. In time, perhaps that will change. Since the mine switched from potash to polyhalite, the rocks coming out have been ground into grains and sold all over the world. There is Boulby polyhalite being sprinkled on the ground in China, in Brazil, in the U.S. and all over Europe. Today, these rocks are used to fertilise the tennis courts at Wimbledon. This obscure mineral is becoming one of the most exciting new things in agriculture and there is something of a gold rush for the stuff.

There is a phrase you sometimes hear: if it’s not grown, it’s mined. Salt, however, is a substance we mine to help us grow—to provide the fertilisers for our crops and the building blocks for our drugs.

Iron was not the first metal we learned to smelt (as you’ll see in the following section) but these days it is the archetypal one, accounting for roughly 95 per cent of all the metal we produce and use.

If you live in a developed economy like the U.S., Japan, UK or most of Europe, you have roughly 15 tonnes of steel in your life.

Thanks to the wonders of material science we now have a decent grasp of why that seemingly small disparity in carbon content makes such a big difference: in steel, those carbon atoms nestle neatly between the iron atoms creating a strong, immoveable lattice. Too much carbon and the structure of the lattice is imperfect, so the metal can easily shatter (cast iron). Too little and the iron atoms can slide over each other without much resistance (wrought iron). Counterintuitively, you want your iron to be nearly pure, but not entirely pure.

(smashing the metal, we now know, was one way of removing some of the carbon),

But while the Forth Bridge used steel, the Eiffel Tower was made out of wrought iron. Bessemer steel had been in production for a few decades, but Gustave Eiffel simply didn’t trust it. And the upshot is that the Eiffel Tower used a lot more iron in shorter spans than would have been necessary with steel—and tall as it is, it could potentially have been taller still. Indeed, you could fit six Eiffel Towers within the Forth Bridge’s main structure.[*2]

In a typical farm in New England in 1800, with mostly wooden tools, it took just over seven minutes of labour to yield a kilogram of grain. In 1850, with cast iron tools, the same job took just under three minutes. By 1900, with steel tools, it was less than 30 seconds per kilogram.

Steel production is responsible for roughly 7–8 per cent of the world’s greenhouse gas emissions.

If we wanted everyone in the world to have the same amount of embedded steel as we enjoy in the rich world—15 tonnes per person—that would imply increasing the total global stock of this alloy to 144 billion tonnes. And since that is nearly four times what we have ever produced since the beginning of humanity, and since methods of producing steel without any emissions remain experimental and expensive, we are caught on the horns of a dilemma. The world’s twin goals of decarbonisation and development are heading for a collision.

China has produced more steel in the past decade than the United States has since the beginning of the twentieth century.

Something which would have taken weeks of work back before Bessemer invented his convertor, was done in minutes. Standing and watching this modern descendent of Sir Henry’s crucible, you start to realise its significance, and how dramatically it changed life in this country and beyond. All of a sudden, steel was widely available and, just as importantly, cheap.

Back in 1810 Americans spent roughly the same proportion of their national income on iron nails as they do today on computers.

One of the least appreciated but most important advances of the twentieth century was the introduction—in this case by the U.S. government under President Herbert Hoover—of a set of product standards, which meant screws and bolts came in certain set sizes rather than in all sorts of random dimensions.

Add manganese (about 1.7 per cent by volume) and you end up with a hard, ductile steel, which is perfect for making train rails. Add silicon and you have an electrical steel you can use alongside the copper in a motor or transformer. Stainless steel, with its anti-rust properties, is 12 per cent chromium, with nickel sometimes added for strength. For aircraft landing gear you will need a strong, ductile, tough alloy, made with molybdenum, silicon and vanadium. And on it goes—there are many hundreds of different varieties of steel alloys these days, but they all begin here, with a small dose of special ingredients plopped into a cauldron of bubbling hot metal.

The strength, electrical performance and corrosion resistance of steel have risen by a factor of nearly ten over the past half-century alone.

Perhaps the best example of this continuous improvement goes back to the most famous of all accidents: the sinking of the Titanic in 1912. The ship was made with what were, at the time, some of the strongest, hardiest steels available. Yet analysis of metals retrieved in recent years from the ship’s hull show that they were made of steel grades that would never pass muster today: high in sulphur, low in manganese and prone to shattering in low temperatures. Many of the rivets that held the steel in place were made of cheap wrought iron rather than steel, which again made them more vulnerable to shattering.

During the Second World War a whole fleet of cargo carriers—the “Liberty Ships”—were built in a hurry to carry goods between the Allies. Many of the ships were made with a steel alloy that performed perfectly well at room temperature but turned brittle in cold weather. So when a few of them sailed into colder waters, they suffered catastrophic damage. A handful simply broke in half without warning.