China may limit or halt sale of rare earth metals to U.S. in tariff war, which are used U.S. in missile guidance and cell phones

China, the world’s largest producer of rare earths and the biggest supplier of rare earth metals to the United States, is considering cutting back on exporting its rare earth metals to the U.S. or even cutting them off entirely. Most of the minerals produced by China the U.S. had originally targeted for tariffs were on a list of 35 minerals published by the U.S. Department of the Interior in May that were deemed critical to the country’s security and economic prosperity. China cut back heavily its sale of rare earth metals to the U.S. in 2010, and this caused triggered a global price increase, harming the U.S. high tech companies. Metal magnets include rare earth oxides neodymium and praseodymium, also dropped off the list. This category accounts for $191.2 million of imports in 2017.

A Chinese-led coalition threatens to further tighten control of the rare earths trade with the purchase of the only operational rare earth metals mine in America. The Mountain Pass Mine in the California desert south of Las Vegas was a powerhouse producer of REEs from 1965 to 1985, at which point China took over global production and never looked back. Mountain Pass was shuttered from 2002 to 2012 because it couldn’t compete with the low prices coming out of China. After a brief revival from 2012 to 2015, Mountain Pass closed for good in 2016 and its owner, Molycorp, filed for bankruptcy. This past June, an investor group with alleged ties to the Chinese government bought the mine for $20.5 million, beating out American bidders including entrepreneur Tom Clarke of ERP Strategic Minerals.

American lives rely on rare earths. LED displays on your smartphone and TV, the energy-efficient light bulbs , disc drive in your laptop, use REEs. Rare earths are prized for a host of unique properties including magnetism, luminescence, and lightweight strength. Ana de Bettencourt-Dias is a rare earth chemist at the University of Nevada, Reno, where she studies the light-emitting properties of REEs. The very first color TVs used rare earths like europium and terbium to create red and green light, and today’s LED and OLED displays are built with REEs that emit light efficiently and with very high color purity.

But Bettencourt-Dias says that the biggest and most important industrial application of REEs has to do with magnets, particularly neodymium-based magnets, which are the strongest in the world. Wind turbines use huge neodymium magnets for their power generators, and smaller neodymium magnets are found in computer hard drives and just about every part of your car, from electric windows to audio speakers.

There are alternatives to REEs for high-tech industrial applications, but they’re less efficient and more expensive. Bettencourt-Dias said that large-scale recycling of electronics could be an alternative source for rare earths, but the cost of physically disassembling smartphones and TVs, and the difficulty of chemically separating rare earths, is still far greater than buying raw materials from China. According to the US Geological Survey, America imported around 13,000 metric tons of rare earth compounds and metals in 2016, and nearly all of it originated in China. Although the US buys certain compounds and components from countries like Japan and France, the raw minerals for most of those imports come from China.

Some minor metals used in high-tech industries, such as bismuth, titanium and cobalt, are still on the tariff list. However, barite and antimony are not included in the new tariffs. Antimony, along with antimony oxide, made up $108.5 million of imports from China last year, according to USTR data. Natural graphite, which is used in steelmaking and lithium-ion batteries, also won a reprieve. Tungsten, used to harden steel, now only features in 11 categories on the final tariff list, half the original number.