One of the singular features of Baotou, an industrial city of 2 million people in Inner Mongolia, is a 10-square-kilometer (4-square-mile) lake that is among the most polluted in the world. The artificial lake, referred to by the name of the dam associated with it, Weikuang Dam (or Baogang Tailings Dam), has for decades collected the effluent from minerals processing for China’s globally dominant iron, steel, and rare-earths industries.
Built in the late 1950s, the lake contains a highly toxic stew of industrial chemicals with substantial amounts of radioactive thorium, the latter resulting primarily from the processing of monazite ores for rare earths. China has since greatly tightened its environmental regulations and restrictions on mining and minerals processing. For example, largely because of the environmental disaster that is Weikuang Dam, the country doesn’t permit the development or operation of stand-alone monazite mines—that is, mines where nothing is mined except monazite ore.
Now, with industrialized nations in North America, Asia, and Europe spending billions to shore up their rare-earths supply chains, and counting on monazite to help them do it, China’s history and experiences with monazite offer important lessons.
This article is a collaboration between Foreign Policy, the global magazine of politics and ideas, and IEEE Spectrum, the flagship magazine of the IEEE.
Monazite ore is a pillar of China’s rare-earths industry because it is a prime source of some less common but extremely important rare-earth elements, notably dysprosium, terbium, yttrium, and erbium. The country mines and processes vast quantities of monazite ore; it also imports huge amounts of monazite ore for processing.
Most of the domestically mined monazite ore comes from a single mine: the mammoth Bayan Obo complex, 150 kilometers north of Baotou in Inner Mongolia. Bayan Obo, which is primarily an iron-ore mine, also happens to contain the largest known rare-earth deposit in the world. It’s the source of nearly half of all the rare-earth ore mined on the planet in a typical year. Most of the rare-earth ore mined at Bayan Obo is a type called bastnaesite; it’s the mining of that bastnaesite that makes it legal to mine monazite ore at Bayan Obo as well.
Related: Can a Radioactive Ore Break China’s Grip on Rare Earths?
All told, ore from Bayan Obo was used to produce 170,000 tonnes of rare-earth metal last year, according to David Merriman, research director at the minerals intelligence firm Project Blue. Roughly 30 to 40 percent of the rare-earth ore mined at Bayan Obo is monazite. That amount alone would be enough to make China the world’s largest processor of monazite for rare earths.
China’s 2025 Monazite Imports Topped 70,000 Tonnes
But a more detailed picture of China’s interest in monazite emerges when you consider the country’s imports of the ore. Last year they amounted to more than 70,000 tonnes, says Thomas Kruemmer, a Singapore-based consultant on minerals and metals. That figure becomes more impressive when you consider the unique challenges of shipping monazite by sea. Because of its radioactivity, concentrated monazite ore is classified as Class 7 dangerous cargo under the International Maritime Dangerous Goods Code. That means, Kruemmer notes, that the ore can be imported through only four ports in China.
In addition, importation of some kinds of monazite into China is supposed to go through a joint venture consisting of the China National Nuclear Corp. and Shenghe Resources, which are at least partly state-owned. But lots of imported monazite doesn’t go through those organizations, notes Merriman. That’s because heavy mineral sands, which may contain roughly 2 or 3 percent monazite by weight, are not subject to the same import controls as concentrated monazite ore. So companies import the heavy mineral sands; separate out various profitable concentrates, including the monazite mineral concentrate; and then process the monazite concentrate to recover the rare earths.
China has lately stepped up its efforts to secure rare-earth ore around the world. One reason, says Kruemmer, is simply to make up for recently lost supplies. In 2025, the U.S. government invested US $400 million in MP Materials, which operates the Mountain Pass mine and processing facility in California. The deal put an end to longstanding contracts under which MP Materials had been selling tens of thousands of tonnes of rare-earth concentrate annually to a trading affiliate of Shenghe Resources.
But other Westerners speculate that China has strategic reasons for stepping up its efforts to acquire heavy mineral sands or other rare-earth assets abroad. By locking down rights to deposits or projects abroad, Chinese organizations are making them unavailable to non-Chinese developers, according to this reasoning.
Merriman points out that your view of these activities largely depends on where you sit. The U.S. government recently made a conditional loan commitment of up to $725 million to U.S. monazite processor Energy Fuels, which has been aggressively securing substantial monazite supplies in Australia, Brazil, and Madagascar. To a Chinese observer, those moves probably look rather strategic.
China, meanwhile, is doing what it has been doing for decades. “China’s playing its game,” says Merriman.