Can metals that occur naturally in seawater be mined? And can they be mined sustainably? An Oakland, Calif., company says so. And not only do we extract magnesium from seawater and industrial waste brine, we do it in a carbon-neutral way. Magratea Metals is producing small amounts of magnesium in a pilot project and is building a larger facility with funding from the U.S. Department of Defense that will produce about 200 tons of the metal annually. The company plans to start operating a facility capable of producing more than 11,000 tons per year by 2028.
The government funded the project because magnesium is much lighter and stronger than iron and is essential for aircraft, automobiles, steel and defense industries. Currently, China produces about 85 percent of the world's magnesium using a dirty, carbon-intensive process. Therefore, finding a way to produce magnesium domestically using renewable energy is not only an economic and environmental issue, but also a strategic issue. Alex Grant, CEO of Magratea and an expert in the field of decarbonizing metal production, said: „With one finger, China could halt magnesium exports and shut down U.S. steel production.'' I can do that.''
„China uses a lot of coal and a lot of labor,“ Grant continued. „We don't use any coal and it requires a lot less labor.“ One reason this method is lower cost, he says, is because the company uses wind and solar energy during the cheapest off-peak hours. This is because it can be used for As a result, Grant estimates their metal costs will be about half that of traditional ore producers.
Every day, desalination plants around the world produce 37 billion gallons of brine containing copper, zinc, and other metals.
Magrathea — named after the planet featured in the hit novel Hitchhiker's Guide to the Galaxy — Often, waste brine is purchased from a desalination plant and the water is evaporated leaving behind magnesium chloride salts. An electric current is then passed through the salt to separate it from the molten magnesium, which is then cast into ingots or machine parts.
Humans have long obtained minerals and chemicals from seawater, and although sea salt has been extracted from seawater for thousands of years, researchers around the world are now expand the scope This is because demand for lithium, cobalt and other metals used in battery technology is increasing. Companies are scrambling to find new deposits in unlikely places to avoid mining ore bodies and reduce pollution. The next frontier for important minerals and chemicals appears to be brine, or salt water.
Salt water comes from a variety of sources, many of which are new. the study It focuses on the possibility of extracting metals from salty waste produced by industries such as coal-fired power plants that discharge their waste into tailings ponds. Wastewater pumped from oil and gas wells – called produced water. Wastewater from hard rock mining. and a desalination plant.
A technician casts a magnesium ingot at the Magratea Metals facility in Oakland, California.
alex grant
Large-scale saltwater mining can have negative effects on the environment, for example, requiring the disposal of some waste. However, as there is currently no large-scale activity, the potential impact is unknown. Still, the process is expected to have a number of positive effects, chief among them being that it does not cause large-scale land disturbance or the acid mine drainage and other pollution associated with hard rock mining. It is possible to produce valuable metals.
According to Brine Miners, a research center at Oregon State University, there are approximately 18,000 desalination plants around the world that take in 23 trillion gallons of seawater annually and force it through semipermeable membranes in a process called reverse osmosis. or other methods of separating water molecules from impurities. Every day, this plant produces more than 37 billion gallons of brine. That's enough to fill 50,000 Olympic-sized swimming pools.That solution includes: big Amount of money Copper, zinc, magnesium and other valuable metals.
Disposing of brine from desalination plants has always been a challenge. In coastal areas, desalination plants send their waste back into the ocean, where it can be deposited on the ocean floor and damage marine ecosystems. Salt water is so concentrated that it is toxic to plants and animals. Inland desalination plants bury or inject waste into wells. These processes further increase the cost of an already expensive process, and as desalination plants increase, the problem will only increase. Multiply World wide.
Salt water from desalination plants contains more than 17,400 tons of lithium, a substance worth an estimated $2.2 trillion.
Finding profitable and safe uses for brine can help solve waste problems in factories, and by using the brine to feed other processes, the residue from one industrial activity can become a feedstock for a new one. will encourage plants towards a circular economy. According to OSU estimates, brine from desalination plants contains the following components: $2.2 trillion It contains more than 17,400 tons of valuable materials, including lithium, which is essential for the production of batteries for electric vehicles, household appliances, and electrical energy storage systems. In some cases, mining brine for lithium and other metals and minerals can make the remaining waste stream less toxic.
For decades, manufacturers have extracted magnesium and lithium from natural brine. In 2023, the federal government says California's Salton Sea contains enough lithium to meet the nation's needs for decades. analysiscompanies drilled geothermal wells to generate the energy needed to separate metals from brine.
And ExxonMobil recently built one of the world's largest lithium processing facilities in rural Arkansas, viz. siphon lithium It is extracted from salt water deep within the Smackover formation. The company aims to produce 15% of the world's lithium by 2030.
Miners have largely ignored the minerals in desalinated water because it is not economical to concentrate them.but new science and technology Innovations such as have created more effective separation methods, allowing companies to focus on this vast resource.
„Three vectors are converging,“ said Peter Fisk, director of the National Alliance for Water Innovation at the Department of Energy's Lawrence Berkeley National Laboratory in Berkeley. “The value of some of these critical materials is rising. The cost of conventional (open pit) mining and mining is rising. And the safety of international suppliers, particularly Russia and China, is declining. doing.“
There is also a focus on projects and businesses that have very low, zero or negative greenhouse gas emissions and can be part of a circular economy, with funding from sources such as the Department of Defense and Department of Energy. There is. Researchers who study brine mining believe the holy grail of desalination – finding more than enough value in waste brine to pay for the expensive process of creating fresh water – is within reach.
New technology could allow companies to „sweep through wastewater trash piles and extract high-value items,“ researchers say.
Improved filtration technology can now remove much more – and much smaller – substances suspended in salt water. „We now have membranes that select individual ions,“ Fisk says. “Thanks to this technology, we can sift through the trash pile of wastewater and extract high-value items.” One of the fundamental concepts driving this research is that “there is no such thing as wastewater. That’s it,” he says.
NEOM, a controversial and hugely expensive futuristic city being built in the Saudi Arabian desert, will include a desalination plant and waste mining for minerals and chemicals that must be disposed of. We assembled a highly acclaimed international team to build a facility to minimize the amount of waste. of. ENOWA, NEOM's water and energy division, Claim Its selective membrane, which includes reverse and forward osmosis, targets specific minerals and extracts 99.5 percent of the potassium chloride in waste brine, an important fertilizer with high market value. This system uses half the energy and requires half the capital cost compared to traditional potassium chloride production methods. ENOWA said it is developing other selective membranes to treat other minerals such as lithium and rubidium salts from waste brine.
The Brine Miner Project in Oregon has created an experimental system to desalinate seawater and extract lithium, rare earths, and other metals. The entire process is done using green hydrogen, which researchers produce by splitting hydrogen and oxygen molecules in water using renewable energy. „We're aiming for a circular process,“ said Zhenxing Feng, who leads the project at OSU. „There are no wasted parts.“
The Kay Bailey Hutchison desalination plant in El Paso, Texas, produces waste brine containing gypsum and hydrochloric acid.
Jeffrey Phillips (via Flickr)
The concept of mining desalinated brine and other wastewater is being explored and implemented around the world. At Delft University of Technology in the Netherlands, researchers have extracted what they call „biobased materials.“ Cowmera It is produced from sludge particles formed during the treatment of municipal wastewater. Both a binder and an adhesive, as well as repelling and retaining water, Kaumera can be used in the agricultural, textile and construction industries when combined with other raw materials.
Another large European project called sea for valuehas partners in eight countries and uses a combination of technologies to concentrate, extract, purify and crystallize 10 target elements from salt water. Publicly funded laboratories in the United States, such as the Department of Energy's Ames Laboratory at Iowa State University and the Oak Ridge National Laboratory in Tennessee, also extract lithium and other materials important for energy transitions from natural and industrial brines. Researching new methods. .
The Kay Bailey Hutchison Desalination Plant in El Paso, Texas, supplies more than 27 million gallons of fresh water per day from a brackish aquifer and transports waste brine by truck and pumps it to injection wells 35 miles away. It is injected withBut first, a company called spring waterhas a facility near a desalination plant that squeezes more potable water from the salt water and uses the remaining waste to make gypsum and hydrochloric acid for industrial customers.
Although the industry faces stricter regulation, experts say the outlook for saltwater mining is bright.
There are hurdles to making a saltwater mining project successful. Christos Charisiadis, saltwater innovation manager for the NEOM portfolio, identified several potential bottlenecks. A lack of transparency in innovation by the water industry can obscure technology issues. Insufficient understanding of potential environmental issues due to lack of comprehensive life cycle assessment. complex and inconsistent regulatory framework; and fluctuations in commodity prices.
Still, Nathanial Cooper, an assistant professor at the University of Cambridge, Prospects for metal recovery from various industrial and natural brines are considered promising as environmental regulations for a wide range of industries become increasingly stringent.
„Companies that produce wastewater will be required to redouble their efforts to ensure that pollutants and hazardous substances are removed from the wastewater they dispose of,“ he said. “Many companies will be forced to find ways to recover these materials. There is great potential to recover many valuable materials from wastewater and contribute to a circular economy.”