extract

Sand mining and the environment

March 18, 2025 By EarthWise Leave a Comment

Sand mining is the world’s largest mining endeavor. It is responsible for 85% of all mineral extraction. It is also the least regulated, possibly the most corrupt, and likely the most environmentally destructive. Sand is the second-most exploited natural resource in the world after water. Its global use has tripled in the past two decades. More than 50 billion tons of sand is extracted from the environment each year.

Sand plays a critical role in much of human development around the world. It is a key ingredient of concrete, asphalt, glass, and electronics. It is relatively cheap and relatively easy to extract. But we use enormous amounts of it.

Sand mining is a major threat to rivers and marine ecosystems. It is linked to coastal erosion, habitat destruction, the spread of invasive species, and damage to fisheries.

The harm from sand mining is only beginning to attract widespread attention. A recent study by an international group of scientists published in the journal One Earth identifies threats posed by sand mining. Sand extraction in marine environments remains largely overlooked, despite sand and sediment dredging being the second most widespread human activity in coastal areas after fishing.

Sand is generally seen as an inert, abundant material, but it is an essential resource that shapes coastal and marine ecosystems, protects shorelines, and sustains both ecosystems and coastal communities. Sand extraction near populated coastlines is particularly problematic as climate change makes coastlines increasingly fragile.

Like all other resources on our planet, even sand cannot be taken for granted. It must be responsibly managed.

**********

Web Links

The rising tide of sand mining: a growing threat to marine life

Photo, posted February 7, 2013, courtesy of Pamela Spaugy / U.S. Army Corps of Engineers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A better way to extract lithium

December 10, 2024 By EarthWise Leave a Comment

Lithium is the critical component in the batteries that power phones and computers, electric cars, and the systems that store energy generated by solar and wind farms. Lithium is not particularly rare, but it is difficult and often environmentally harmful to extract from where it is found.

Traditional ore sources are increasingly difficult and expensive to mine. The largest known deposits of lithium are in natural brines – the salty water found in geothermal environments. These brines also contain other ions like sodium, potassium, magnesium, and calcium, and efficiently separating out the lithium is extremely challenging.

Traditional separation techniques consume large amounts of energy and produce chemical waste, particularly hazardous chlorine gas. These techniques typically suffer from poor selectivity; that is, the process is interfered with by the other ions present in natural brines.

A team of researchers at Rice University has developed a three-chamber electrochemical reactor that improves the selectivity and efficiency of lithium extraction from brines. The middle chamber of the reactor contains a specialized membrane that acts as a barrier to chloride ions, preventing them from getting to the electrode area where they can form chlorine gas.

The new reactor has achieved a lithium purity rate of 97.5%, which means the setup can effectively separate lithium from other ions in the brine and allow the production of high-quality lithium hydroxide, the key material for battery manufacturing.

The Rice University reactor design has the potential to be a game changer for lithium extraction from geothermal brines.

**********

Web Links

‘Game changer’ in lithium extraction: Rice researchers develop novel electrochemical reactor

Photo, posted October 21, 2023, courtesy of Simaron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lithium in Arkansas

November 28, 2024 By EarthWise Leave a Comment

Lithium is the critical raw material in the batteries that power electric cars as well as cell phones, computers, and other gadgets. The stuff has been nicknamed “white gold” for good reason. Chile and Australia are the world’s largest producers of the metal, which is mostly extracted from brine in evaporation ponds. The majority of it is then processed in China. The energy industry has been increasingly working to produce the raw materials needed to produce lithium-ion batteries in the United States and process those materials domestically. There are multiple projects at various stages across the country.

Researchers at the US Geological Survey and the Arkansas state government recently announced that they have discovered a vast trove of lithium in an underground brine reservoir in Arkansas.

With a combination of water testing and machine learning, the researchers determined that there could be 5 to as much as 19 million tons of lithium in the geological area called the Smackover Formation. This is more than enough to meet all the world’s demand for it.

Several companies – including Exxon Mobil, which is covering its bets on the future of oil as an energy source – are developing projects in Arkansas to produce lithium. If these companies can develop and scale up economical new ways to extract lithium from salty water, the region in Arkansas could become the lithium capital of the world.

Energy and mining companies have produced oil, gas, and other natural resources in the Smackover Formation, which extends from Texas to Florida. The same brines have long been the source of other valuable substances.

**********

Web Links

Arkansas May Have Vast Lithium Reserves, Researchers Say

Photo, posted May 22, 2020, courtesy of the European Space Agency via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Water from thin air

September 6, 2024 By EarthWise Leave a Comment

The Earth’s atmosphere contains enormous amounts of water. Being able to efficiently and economically extract some of it to provide drinking water would be extremely beneficial to the billions of people across the globe who face chronic water shortages.

There are existing technologies for atmospheric water harvesting – or AWH. But there are downsides associated with size, cost, and efficiency. A new device developed by mechanical engineering researchers at the University of Utah has the potential to provide a new drinking water source in arid places.

The device is a compact, rapid-cycling, fuel-fired AWH device. It relies on adsorbent materials that draw water molecules out of non-humid air and then applies heat to release those molecules into liquid form.

Hygroscopic materials are those that have an affinity for water and soak it up at every opportunity. Such materials are used, for example, in disposable diapers. The Utah device makes use of metal organic frameworks, which have enormous amounts of surface area on the molecular scale.

The initial work on the Utah device targeted a small compact water generation unit for soldiers in the field. Instead of lugging around a large canteen filled with water, the small unit can produce water on demand. The prototype was able to produce 5 liters of water per day per kilogram of adsorbent material. Within three days in the field, the system outperforms packing water. The heat required to precipitate the liquid water was provided by a standard-issue Army camping stove.

Non-military needs are the ultimate application for the device. The researchers have applied for a patent for what they hope will be a potential solution to a persistent global problem.

*********

Web Links

Producing water out of thin air

Photo, posted August 9, 2012, courtesy of Enid Martindale via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

China And Rare Earth Mining

September 4, 2019 By EarthWise Leave a Comment

Rare earth elements are a crucial part of much of modern technology. Everything from computers to X-ray machines and aircraft engines needs one or more rare earth elements for magnets, lenses, and other functions. The world’s tech giants such as Apple, Huawei, and Tesla depend on suppliers of rare earths.

Rare earth elements are not actually rare, but they are very expensive to extract in ways that are not extremely harmful to the environment. China has been a major source of these elements since its rare earth mining industry took off in the 1990s. The removal of rare earths from the earth’s crust, using a mix of water and chemicals, has caused extensive water and soil pollution.

Today, concrete leaching ponds and plastic-lined wastewater pools dot the hills of Southeast China. Large wastewater ponds sit uncovered and open to the elements in many places. Landslides or barrier failures can spill contaminated contents into waterways or groundwater.

Local and federal officials in China have started to shut down illegal and small-scale rare earth mining operations and have embarked on a cleanup of polluted sites. The rare earth mining cleanup operation is part of wider efforts across China to address severe problems of water, air and soil pollution.

China’s Ministry of Industry and Information Technology estimated that the cleanup bill for southern Jiangxi Province could amount to more than $5 billion. Many environmental experts and local officials say that the cost of the cleanup should not be shouldered by the Chinese government alone, but also by the rare earth industry and the global companies and consumers that benefit from rare earth technology. As rare earth mining efforts start up elsewhere around the world, it is important not to repeat the mistakes made in China.

**********

Web Links

China Wrestles with the Toxic Aftermath of Rare Earth Mining

Photo, posted April 21, 2019, courtesy of John Beans via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Biofuel Waste Into Valuable Chemicals

December 20, 2017 By EarthWise Leave a Comment

When biofuels are made, tough plant material is left over as waste. The material is lignin, which is a main component of plant cell walls that gives plants their structural integrity. Lignin is made up of many valuable compounds, but taking it apart to extract them is very difficult.