China will halt the export of a range of rare-earth technologies, potentially making it harder for the US and other western nations to bolster supplies of strategic raw materials.

Beijing put technology for making rare-earth metals and rare-earth magnets on a list of items can’t be transfered overseas, according to a document from the Ministry of Commerce. The move by the world’s dominant supplier of the minerals comes as its geopolitical rivals rush to cut reliance on materials produced in China.

Over the past three decades, China has built a dominant role in mining and refining rare earths, a cluster of 17 elements used in everything from wind turbines to military hardware and electric vehicles. 

The new rules don’t affect shipments of rare-earth products themselves, but may be intended to frustrate efforts to develop the industry outside China.

Critical metals are coming under the spotlight more as Western nations increasingly view supplies as a matter of national security — especially as the global energy transition stokes fears of potential shortages in the future.

The US is spearheading a drive to reduce China’s stranglehold over flows of minerals from rare earths to lithium and cobalt. President Joe Biden’s flagship climate legislation includes rules aimed at generating more supply domestically or from allied nations. China has responded with restrictions on the export of gallium, germanium and graphite.

While Biden’s landmark legislation and Europe’s Critical Raw Materials Act promise to unlock new funding for prospective suppliers, Beijing’s latest salvo underscores the technical challenges that Western producers could face in developing refining processes that China has come to master over the decades.

Until relatively recently, there were barely any rare-earth refineries at all outside of China. That means its companies and researchers have built a substantial technological and practical advantage in how to extract and process rare earths, while expertise elsewhere has lagged.

The ban-list includes technology for separating rare earths as well producing metal and magnets. Technology for mining, ore-dressing and smelting was listed as “restricted,” rather than banned.

China’s grip over the global rare-earths market first gained broad international attention in 2010, when China imposed tight restrictions on exports. The US, European Union and Japan eventually forced Beijing to overturn the measures via the World Trade Organization. But concerns about its dominance have lingered as Western suppliers faced commercial, technical and environmental setbacks in developing alternative supplies.

China accounted for more than two-thirds of mined rare earths last year, and is home to as much as all global refining capacity, according to US government figures. The country also dominates the supply of rare-earth magnets, the main product deployed in manufactured goods.