Mining And Refining: Pure Silicon And The Incredible Effort It Takes To Get There

November 15, 2021 by 30 Comments

Were it not for the thin sheath of water and carbon-based life covering it, our home planet would perhaps be best known as the “Silicon World.” More than a quarter of the mass of the Earth’s crust is silicon, and together with oxygen, the silicate minerals form about 90% of the thin shell of rock that floats on the Earth’s mantle. Silicon is the bedrock of our world, and it’s literally as common as dirt.

But just because we have a lot of it doesn’t mean we have much of it in its pure form. And it’s only in its purest form that silicon becomes the stuff that brought our world into the Information Age. Elemental silicon is very rare, though, and so getting appreciable amounts of the metalloid that’s pure enough to be useful requires some pretty energy- and resource-intensive mining and refining operations. These operations use some pretty interesting chemistry and a few neat tricks, and when scaled up to industrial levels, they pose unique challenges that require some pretty clever engineering to deal with.

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Mining And Refining: Mine Dewatering

October 17, 2024 by 9 Comments

From space, the most striking feature of our Pale Blue Dot is exactly what makes it blue: all that water. About three-quarters of the globe is covered with liquid water, and our atmosphere is a thick gaseous soup laden with water vapor. Almost everywhere you look there’s water, and even where there’s no obvious surface water, chances are good that more water than you could use in a lifetime lies just below your feet, and accessing it could be as easy as an afternoon’s work with a shovel.

And therein lies the rub for those who delve into the Earth’s depths for the minerals and other resources we need to function as a society — if you dig deep enough, water is going to become a problem. The Earth’s crust holds something like 44 million cubic kilometers of largely hidden water, and it doesn’t take much to release it from the geological structures holding it back and restricting its flow. One simple mineshaft chasing a coal seam or a shaft dug in the wrong place, and suddenly all the hard-won workings are nothing but flooded holes in the ground. Add to that the enormous open-pit mines dotting the surface of the planet that resemble nothing so much as empty lakes waiting to fill back up with water if given a chance, and the scale of the problem water presents to mining operations becomes clear.

Dewatering mines is a complex engineering problem, one that intersects and overlaps multiple fields of expertise. Geotechnical engineers work alongside mining engineers, hydrogeologists, and environmental engineers to devise cost-effective ways to control the flow of water into mines, redirect it when they can, and remove it when there’s no alternative.

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Mining And Refining: Tungsten

April 2, 2024 by 16 Comments

Our metallurgical history is a little bit like a game of Rock, Paper, Scissors, only without the paper; we’re always looking for something hard enough to cut whatever the current hardest metal is. We started with copper, the first metal to be mined and refined. But then we needed something to cut copper, so we ended up with alloys like bronze, which demanded harder metals like iron, and eventually this arms race of cutting led us to steel, the king of metals.

But even a king needs someone to keep him in check, and while steel can be used to make tools hard enough to cut itself, there’s something even better for the job: tungsten, or more specifically tungsten carbide. We produced almost 120,000 tonnes of tungsten in 2022, much of which was directed to the manufacture of tungsten carbide tooling. Tungsten has the highest melting point known, 3,422 °C, and is an extremely dense, hard, and tough metal. Its properties make it an indispensible industrial metal, and it’s next up in our “Mining and Refining” series.

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Mining And Refining: Quartz, Both Natural And Synthetic

September 6, 2023 by 17 Comments

So far in this series, pretty much every material we’ve covered has had to undergo a significant industrial process to transform it from its natural state to a more useful product. Whether it’s the transformation of bauxite from reddish-brown clay to lustrous aluminum ingots, or squeezing solid sulfur out of oil and natural gas, there haven’t been many examples of commercially useful materials that are taken from the Earth and used in their natural state.

Quartz, though, is at least a partial exception to this rule. Once its unusual electrical properties were understood, crystalline quartz was sent directly from quarries and mines to factories, where they were turned into piezoelectric devices with no chemical transformation whatsoever. The magic of crystal formation had already been done by natural processes; all that was needed was a little slicing and dicing.

As it turns out, though, quartz is so immensely useful for a technological society that there’s no way for the supply of naturally formed crystals to match demand. Like copper before it, which was first discovered in natural metallic deposits that could be fashioned into tools and decorations more or less directly, we would need to discover different sources for quartz and invent chemical transformations to create our own crystals, taking cues from Mother Nature’s recipe book on the way.

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Mining And Refining: Helium

June 15, 2022 by 46 Comments

With a seemingly endless list of shortages of basic items trotted across newsfeeds on a daily basis, you’d be pardoned for not noticing any one shortage in particular. But in among the shortages of everything from eggs to fertilizers to sriracha sauce has been a growing realization that we may actually be running out of something so fundamental that it could have repercussions that will be felt across all aspects of our technological society: helium.

The degree to which helium is central to almost every aspect of daily life is hard to overstate. Helium’s unique properties, like the fact that it remains liquid at just a few degrees above absolute zero, contribute to its use in countless industrial processes. From leak detection and welding to silicon wafer production and cooling the superconducting magnets that make magnetic resonance imaging possible, helium has become entrenched in technology in a way that belies its relative scarcity.

But where does helium come from? As we’ll see, the second lightest element on the periodic table is not easy to come by, and considerable effort goes into extracting and purifying it enough for industrial use. While great strides are being made toward improved methods of extraction and the discovery of new deposits, for all practical purposes helium is a non-renewable resource for which there are no substitutes. So it pays to know a thing or two about how we get our hands on it.

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Mining And Refining: From Red Dirt To Aluminum

December 13, 2021 by 29 Comments

No matter how many syllables you use to say it, aluminum is one of the most useful industrial metals we have. Lightweight, strong, easily alloyed, highly conductive, and easy to machine, cast, and extrude, aluminum has found its way into virtually every industrial process and commercial product imaginable.

Modern life would be impossible without aluminum, and yet the silver metal has been in widespread use only for about the last 100 years. There was a time not all that long ago that aluminum dinnerware was a status symbol, and it was once literally worth more than its weight in gold. The reason behind its one-time rarity lies in the effort needed to extract the abundant element from the rocks that carry it, as well as the energy to do so. The forces that locked aluminum away from human use until recently have been overcome, and the chemistry and engineering needed to do that are worth looking into in our next installment of “Mining and Refining.”

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Hackaday Podcast 145: Remoticon Is On, Movie FX, Cold Plasma, And The Purest Silicon

November 19, 2021 by 3 Comments

With literally just hours to go before the 2021 Hackaday Remoticon kicks off, editors Tom Nardi and Elliot Williams still managed to find time to talk about some of the must-see stories from the last week. There’s fairly heavyweight topics on the docket this time around, from alternate methods of multiplying large numbers to the incredible engineering that goes into producing high purity silicon. But we’ll also talk about the movie making magic of Stan Winston and some Pokemon-themed environmental sensors, so it should all balance out nicely. So long as the Russian’s haven’t kicked off the Kessler effect by the time you tune in, we should be good.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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