Growing Opals In The Lab

Opals are unique amongst gemstones, being formed from tiny silica nanospheres arranged in precise structures that give them their characteristic shifting color when seen from different angles. [The Thought Emporium] loves a challenge, so set about growing some himself.

It’s not the hardest gemstone synthesis ever, but it’s no cakewalk either. The process requires tetraethyl orthosilicate, or TEOS, which can be difficult to find, but the rest of the chemicals required are commonly available. The initial phase involves mixing the TEOS with reactants to form nanoscale silica spheres in the range of 200-350 nanometers wide. With the spheres in solution, the mixture must then be carefully dried in such a way as to create the right structure to produce opal’s famous color effects. At this stage, industrial producers add further silica to stabilize the matrix, though [The Thought Emporium] wasn’t able to find literature that explained how to do this. Instead, he relied on resin, which while imperfect, did allow the specimens to be stabilised and shown off for the purposes of the video.

The video notes that many of the steps in this process were perfected decades ago, but remain held as trade secrets, making replication an exercise in experimentation. Nonetheless, success was had in producing recognisably opalescent specimens, and we can’t wait to see further refinement of the DIY process.

We’ve seen similar work from [The Thought Emporium] before, exploring structural color and holograms. Video after the break.

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Recovering Metal From Waste

Refining precious metals is not as simple as polishing rocks that have been dug out of the ground. Often, complex chemical processes are needed to process the materials properly or in high quantities, but these processes leave behind considerable waste. Often, there are valuable metals left over in these wastes, and [NerdRage] has gathered his chemistry equipment to demonstrate how it’s possible to recover these metals.

The process involved looks to recover copper and nitric acid from copper nitrate, a common waste byproduct of processing metal. While a process called thermal decomposition exists to accomplish this, it’s not particularly efficient, so this alternative looks to improve the yields you could otherwise expect. The first step is to react the copper nitrate with sulfuric acid, which results in nitric acid and copper sulfate. From there, the copper sulfate is placed in an electrolysis cell using a platinum cathode and copper anodes to pass current through it. After the process is complete, all of the copper will have deposited itself on the copper electrodes.

The other interesting thing about this process, besides the amount of copper that is recoverable, is that the sulfuric acid and the nitric acid are recoverable, and able to be used again in other processes. The process is much more efficient than thermal decomposition and also doesn’t involve any toxic gasses either. Of course, if collecting valuable metals from waste is up your alley, you can also take a look at recovering some gold as well.

Thanks to [Keith] for the tip!

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Lithium: What Is It And Do We Have Enough?

Lithium (from Greek lithos or stone) is a silvery-white alkali metal that is the lightest solid element. Just one atomic step up from Helium, this magic metal seems to be in everything these days. In addition to forming the backbone of many kinds of batteries, it also is used in lubricants, mood-stabilizing drugs, and serves as an important additive in iron, steel, and aluminum production. Increasingly, the world is looking to store more and more power as phones, solar grids, and electric cars continue to rise in popularity, each equipped with lithium-based batteries. This translates to an ever-growing need for more lithium. So far production has struggled to keep pace with demand. This leads to the question, do we have enough lithium for everyone?

It takes around 138 lbs (63 kg) of 99.5% pure lithium to make a 70 kWh Tesla Model S battery pack. In 2016, OICA estimated that the world had 1.3 billion cars in use. If we replace every car with an electric version, we would need 179 billion pounds or 89.5 million tons (81 million tonnes) of lithium. That’s just the cars. That doesn’t include smartphones, laptops, home power systems, massive grid storage projects, and thousands of other products that use lithium batteries.

In 2019 the US Geological Survey estimated the world reserves of identified lithium was 17 million tonnes. Including the unidentified, the estimated total worldwide lithium was 62 million tonnes. While neither of these estimates is at that 89 million ton mark, why is there such a large gap between the identified and estimated total? And given the general rule of thumb that the lighter a nucleus is, the more abundant the element is, shouldn’t there be more lithium reserves? After all, the US Geological Survey estimates there are around 2.1 billion tonnes of identified copper and an additional 3.5 billion tonnes that have yet to be discovered. Why is there a factor of 100x separating these two elements?

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A 3D Printed Magnetic Stirrer For Your DIY Chemistry Projects

When mixing or agitating delicate solutions in the chemistry lab, a magnetic stirrer is often the tool of choice. They’re able to be easily sterilized and cleaned, while maintaining isolation between the mechanical parts and the solutions in question. While they can be purchased off the shelf, [Max Siebenschläfer] whipped up a design that can easily be built at home.

The build consists of a 3D printed base, containing a simple brushed motor. This is hooked up to a motor controller fitted with a simple potentiometer for adjusting the speed of rotation. The motor is then fitted with a small 3D printed spinner containing two magnets. A similar 3D printed part acts as a stirrer, and is fitted with a matching pair of magnets, and dropped into the solution. The magnets in the stirrer are attracted to the ones on the end of the motor, and so when the motor spins, the stirrer spins in the solution, with no physical contact required.

It’s a simple way to build a magnetic stirrer at home without having to shell out big money for a laboratory grade unit. We imagine this could be put to fun use for stirring coffee or cocktails, too – if built with a food-grade spinner. More advanced designs are also possible for the eager home scientist. Video after the break.

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Jan Czochralski And The Silicon Revolution

If you were to travel back in time to the turn of the previous century and try to convince the average person that the grains of sand on just about any beach would be the basis of an industry worth hundreds of billions of dollars within 100 years, they’d probably have thought you were crazy. Aside from being coarse, rough, and irritating, sand is everywhere, and convincing anyone of its value would be a hard sell, unless your interlocutor was a real estate visionary with an appreciation of the future value of seaside property and a lot of patience.

Fast forward to our time, and we all know the value of the material that comes from common quartz sand: silicon, specifically the ultra-purified crystals of silicon that end up as the wafers we depend on to build the circuitry of life. The trip from beach to chip foundry is a long and non-obvious one which would not have been possible without the insights of an undistinguished Polish student and one-time druggist who discovered the process that made the Information Age possible: Jan Czochralski.

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Compile A Hydroponics System From Source

Tending to a garden is usually a rewarding endeavor, as long as there is good soil to work with. If there isn’t, it can either get frustrating quickly having to deal with soils like sand or hard clay, or it can get expensive by having to truck in compost each year. Alternatively, it’s possible to set up systems of growing plants that don’t need any soil at all, although this requires an automated system otherwise known as hydroponics to manage water and nutrients sent to the plants.

This setup by [Kyle] is unique in that it uses his own open-source software which he calls Mycodo to control the hydroponic system. It is loaded onto a Raspberry Pi 4 (which he notes can now be booted from a USB drive instead of an SD card) which controls all of the peripherals needed for making sure that the water has the correct amount of nutrients and chemical composition.

The build is much more than just a software control panel, though. [Kyle] walks through every part of setting up a small hydroponic system capable of effectively growing 15-20 plants indoors. He grows varieties of lettuce and basil, but this system can work for many more types of plants as well. With just slight variations, a similar system can not only grow plants like these, but fish as well.

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DIY Closed-Cell Silicone Foam

Most of us have a junk drawer, full of spare parts yanked from various places, but also likely stocked with materials we bought for a project but didn’t use completely. Half a gallon of wood glue, a pile of random, scattered resistors, or in [Ken]’s case, closed-cell silicone foam. Wanting to avoid this situation he set about trying to make his own silicone foam and had a great degree of success.

Commercial systems typically rely on a compressed gas of some sort to generate the foam. Ken also wanted to avoid this and kept his process simple by using basic (pun intended) chemistry to generate the bubbles. A mixture of vinegar and baking soda created the gas. After a healthy amount of trial and error using silicone caulk and some thinner to get the mixture correct, he was able to generate a small amount of silicone foam. While there only was a bit of foam, it was plenty for his needs. All without having a stockpile of extra foam or needing to buy any specialized equipment.

We appreciate this project for the ingenuity of taking something relatively simple (an acid-base reaction) and putting it to use in a way we’ve never seen before. While [Ken] doesn’t say directly on the project page what he uses the foam for, perhaps it or a similar type of foam could be used for building walk-along gliders.

Photo via Wikimedia Commons