A new technique for recovering lithium from wastewater brine could see the battery revolution spurred on by the shale boom. Ros Davidson reports
In a dramatic scientific breakthrough, researchers in the US have developed a new method for extracting lithium efficiently from wastewater produced during fracking.
Global demand for lithium is surging because of the metal’s use in battery energy storage applications, traditionally in consumer electronics, but more recently in electric vehicles (EVs). Production of the metal increased 12% last year, according to Bloomberg New Energy Finance (BNEF), and analysts Wood Mackenzie expect lithium demand to nearly double from 233,000 tonnes in 2017 to 405,000 tonnes by 2022. Goldman Sachs has forecast that by 2025, demand will reach 570,000 tonnes.
With demand rising, EV and pack manufacturers are eager to lock in supplies – but even with dozens of new mining projects planned the industry may be unable to keep up with demand. Alternative sources of the element are likely to be needed, and the salt-rich wastewater brine produced during unconventional drilling and hydraulic fracturing could become a valuable resource in its own right.
With such opportunity, a team of researchers from universities in Australia, China and the US sought to perfect a new process for gathering the element. The group has successfully developed a metal-organic-framework membrane that mimics the filtering function – or “ion selectivity” – of biological cell membranes. The researchers say that the process easily and efficiently separates metal ions in fracking wastewater, opening the door to what could be a revolutionary new technology for extractive industries.
“It’s basically like going through the garbage and finding things that are valuable,” Dr Benny Freeman, professor at the McKetta Department of Chemical Engineering at the Cockrell School of Engineering, University of Texas at Austin, explained to InnovOil.
Freeman’s colleagues also came from Monash University and the Commonwealth Scientific and Industrial Research Organisation (CSIRO), both of which are in Australia, and the Chinese Academy of Sciences, backed by funding from the Australian Research Council, the Australian-American Fulbright Commission, the CSIRO and the National Computational Infrastructure in Australia. The group’s findings were recently published in the peer-reviewed journal Science Advances.
An alkali metal, lithium is especially common in some of the oilfields of Texas, including the Eagle Ford and Barnett shale plays, but the element has never before been extracted from wastewater produced by hydraulic fracking, at least on a commercial basis. The discovery of a new way to secure this so-called “petro-lithium” could lead to a significant additional income stream for the oil and gas industry.
“Based on preliminary numbers, it looks like an exciting opportunity,” he added. “Produced water has never been exploited [for lithium] – it’s an unknown or new possibility.”
Ion the prize
Much of the excitement around the discovery is in its precision. Membranes have been used in commercial reverse osmosis applications to desalinate water for decades, but not selectively to remove specific ions such as lithium. As an alkali metal it has a small crystal size which attracts a sizeable accompaniment of water molecules. This chemistry leads to a hydrated lithium ion that is large and slow-moving – indeed, it can be the slowest of all such ions when it travels through more conventional polymer membranes.
The membrane operates on principles inspired by highly effective biological cell materials, whose mechanism of operation was discovered by Roderick MacKinnon and Peter Agre and which was the subject of the 2003 Nobel Prize in chemistry.
The new process dehydrates ions as they pass through the membrane channels and removes only select ions, rather than indiscriminately removing all of them. Thus the small lithium ion can perhaps for the first time be attracted without its watery entourage.
“It is a first or exceptionally rare [finding] to be able to transmit ions rapidly based on their dehydrated size,” said Freeman, who described the researchers’ finding as surprising. The result, say the scientists, is a process for extracting lithium that should cost less and consume less energy than conventional methods. Potentially, that could lead to margins high enough to make these lithium recovery plants commercially viable.
Water, water everywhere
It is unclear how widespread lithium is across oilfields elsewhere in the world, because little mapping has been done, especially outside the US. But this is changing.
In light of growing demand, a scramble is currently under way – including in Texas itself by University of Texas researchers – to pinpoint petro-lithium sources globally. The Permian Basin is currently being mapped, but no data are yet available, says Freeman. Other factors do give an indication of where resources could be, however, as most deposits occur in areas where there has been ancient volcanic activity.
The development of the membrane is therefore hugely significant for oil and gas, and the geothermal power industry. About five barrels of water are extracted for every barrel of oil, Freeman noted. Each well in the Barnett and Eagle Ford can generate up to 300,000 gallons (1.2 million litres) of produced water per week. Although the concentration in Texas oilfields varies from site to site, Freeman and his team say that using the new process, one week’s worth of produced water from a single well could provide more than enough lithium to power 200 electric cars or 1.6 million smartphones.
The produced water from the oil and gas industry in Texas alone is simply the largest human-made waste stream in the world, he says. Widening the scope, it is estimated that approximately 80 to 100 million barrels of brine are produced in North America each day, said Investing News in March 2018.
According to a report from the US Department of Energy’s (DoE) Argonne National Laboratory (ANL), even as long ago as 2007 the US oil and gas sector generated 57.4 million barrels of produced water daily. At that time, there were fewer than 1 million actively producing oil and gas wells in the US, and high-volume hydraulic fracking was far from being as widespread as it is today.
“If you’re in the oil business, you’re basically in the water business,” added Freeman.
Petro-lithium could boost the profile of oil and gas players as the world shifts to an electrified future, and supermajors are already taking notice of the demand for energy storage. In 2016 Total bought battery maker Saft Groupe for 950 million euros (US$1.1 billion), and in May 2018 BP’s investment arm, BP Ventures, committed US$20 million to Israeli battery start-up StoreDot. The company says it has developed a lithium ion-based battery technology capable of ultra-fast charging. Slated for release in the mobile market in 2019, the technology will also be deployed in a new type of EV battery that will charge in a time “comparable” to the time needed to refuel a traditional liquid fuel model.
If the researchers’ new cell-membrane process is proven further, commercialisation could occur within three to five years. The scientists have demonstrated proof of principle in the laboratory, says Freeman, and are now working towards pilot tests, after which field trials could begin.
There may even be other applications for the process in other areas of the oil and gas sector, although Freeman said that the team “haven't looked much beyond lithium at this point.”
What is clear, however, is that in a new diversified landscape, as E&P firms move from hydrocarbons producers to energy providers, businesses must look to offer more than a singular product. And in a world where stored energy may be of even greater value than pumped liquids, techniques like these prove that even wastewater could become a lucrative resource.