Cleaning up radioactive tailings from old phosphate mines could be an opportunity for the U.S. to counter Beijing’s hold on strategic resources.
The old Piney Point phosphate mine in Florida. The pond sits in a stack of phosphogypsum, a radioactive waste product from manufacturing fertilizer.
Photographer: Tiffany Tompkins/The Bradenton Herald
Leaks of wastewater at a former phosphate mine prompted evacuation orders and a state of emergency near Tampa Sunday, amid fears that a pile of radioactive mine tailings could collapse. Believe it or not, President Joe Biden should be seeing an opportunity wrapped in this crisis. That’s because cleaning up the vast and neglected phosphogypsum stacks that dot Florida and other parts of the southeastern U.S. could help solve U.S. dependence on imported critical materials, all while removing the looming threat of environmental disaster from local residents.
Phosphogypsum is a byproduct of producing fertilizer from phosphate rock, with more than five metric tons produced for every ton of useful phosphoric acid. It’s worthless in its raw form thanks to concentrations of uranium, radium and other heavy metals that make it too radioactive for use as a soil improver or construction material — purposes for which it would otherwise be well-suited.
Those aren’t the only scarce metals that can be found in phosphate tailings, however. Rare earths are a suite of elements crucial to high-tech applications such as strong magnets and lasers that are the subject of ongoing worries in Washington D.C., thanks to China’s stranglehold on much of the world’s supply. They’re present in concentrations of around 0.2% in Florida’s phosphogypsum, according to one 2017 analysis by a Chinese-U.S. study team. With about 1 billion tons in the stacks, that represents more than two million tons of rare earths, enough to meet global demand for a decade.
As we’ve argued, concerns about China’s control over rare earths are probably overblown given how abundant they are. Relative to Florida’s phosphogypsum stacks, they’re also present in far higher and more profitable concentrations in dedicated rare earth mines, such as California’s Mountain Pass deposit and Mount Weld, in Australia. At the same time, Beijing’s saber-rattling around the elements is the perfect opportunity to kill multiple birds with a single stone.
Here’s how it could work. Waste would be removed from the tailings stacks and processed with leaching and flotation techniques common to the mining industry. That would separate out the rare earths and heavy metals and reduce the radioactivity of the remaining phosphogypsum to permissible levels. It could then be sold for use in agricultural and industrial applications for which it’s currently considered too dangerous. The rare earths would enter the high-tech industrial supply chain, while radium could be used for medical isotopes and uranium could fuel civilian and military nuclear reactors. (That wouldn’t even be a particularly radical departure — in the 1980s, about 20% of U.S. uranium supply was recovered from phosphates.)
Numerous laboratory studies have been carried out looking at processes to achieve this, but to date the economics of scaling things up to industrial levels have been challenging. Prices for phosphate, rare earths, and uranium have all mostly languished in recent years, limiting the commercial appeal of reprocessing the world’s phosphogypsum.
The opportunity for government here is to use its immense purchasing power and research and development expertise to break this equilibrium. The challenge of phosphogypsum is mostly seen as being on the asset side of the ledger: The returns from processing the waste are too low to justify investment. At the same time, there’s a huge and ignored line item on the liability side: Tracts of the country have lived for decades under threat of the sort of environmental crisis now unfolding near Tampa. Off the commercial balance sheet, America’s governments spend substantial sums every year monitoring and managing this risk.
That liability is clearly growing to the point where regulators are ready to overturn some of their own rules. Under the Trump administration last year, the Environmental Protection Agency allowed phosphogypsum to be used in raw form as road-building material, a significant departure from its three-decade ban which is currently being appealed.
Rather than this piecemeal regulation, a far better approach would be to tackle the problem head-on, and fund efforts to commercialize large-scale separation and use of phosphate tailings. As current events are demonstrating, ignoring a radioactive waste problem doesn’t make it go away. This administration is looking to spend $111 billion cleaning up America’s lead pipes and water infrastructure. It should be able to see how the costs of turning Florida’s phosphogypsum into useful and safe products are far lower than those of continuing to kick this can down the road.
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