China will restrict shipments of antimony for reasons of national security, the latest measure in Beijing’s drive to curb exports of strategic metals amid a spiraling trade war with the West. The protectionist measure will take effect on September 15.
The shiny gray metalloid’s biggest application is as a flame retardant, which accounted for around half of global usage in 2023, Reuters said citing brokerage CICC. Around 20% is used to make photovoltaic glass to improve the performance of solar cells, with the rest used in lead-acid batteries, the Reuters report said.
Antimony is also used in military equipment such as infrared missiles, nuclear weapons and night vision goggles, and as a hardening agent for bullets and tanks.
The Chinese Ministry of Commerce (MoC) and the General Administration of Customs said in a statement on Thursday (August 15) that companies need permission from the government to export antimony ore deposits, oxides and hydrides, indium antimonides and organo-antimony compounds and gold-antimony separation technology.
“It is an international practice to implement export controls on antimony, superhard materials and other related items,” a spokesperson for the MoC said in a statement.
The spokesperson said the export controls are not targeted at any specific country or region while exports complying with relevant regulations will be approved. He added that the move aims to safeguard national security and fulfill non-proliferation and other international obligations.
He said the Chinese government opposes any country or region using controlled items from China to engage in activities undermining China’s national sovereignty, security and development interests.
However, a Guangdong-based IT columnist says in an article published on Friday that China wants to use the export controls of antimony to retaliate against the US chip ban.
The writer says China has the world’s largest antimony reserves and production capacity, and should enjoy an advantage in developing infrared tools, high-performance telecommunication devices, alloy products and next-generation semiconductors.
He stresses that Qingdao Haohan Quancai Semiconductor Co Ltd and Optics Technology Holding have already started making next-generation chips using gallium and indium antimonides.
According to the US Geological Survey, China has antimony reserves of 640,000 tons, representing 30% of the world’s total deposits. That’s followed by Russia’s 350,000 tons (16%) and Bolivia’s 310,000 tons (14%). China accounted for 48% of the world’s antimony supply in 2023, followed by Tajikistan at 25% and Turkey at 7%.
Stibine, or antimony hydride, is used in the semiconductor industry to dope silicon with small quantities of antimony via the chemical vapor deposition (CVD) process.
Antimony thin films are good photodetectors. Trimethylstibine, an organoantimony compound, is the raw material in the metalorganic CVD (MOCVD) process used to make infrared light-emitting diodes (IR LEDs).
All these materials can be used in missiles made by US defense contractors including Lockheed Martin and Raytheon, both of which have been sanctioned by China since 2019.
Superhard materials
The MoC and Chinese Customs said China will also restrict the exports of cubic press and microwave plasma-enhanced CVD (MPCVD) machines, which can make synthetic diamonds and diamond coatings, respectively.
Cubic press machines can make lab-grown diamonds at high temperature and under high pressure. Gallium nitride (GaN) semiconductors with a diamond substrate, or GaN-on-diamond, are ideal for the making of high-power, high-frequency devices such as amplifiers and transmitters for military use.
Media reports said Chinese cubic press makers include Luoyang Qiming and Guilin Metallurgical Machinery General Factory. Global players include Germany’s Max Voggenreiter GmbH, which has a unit in Beijing.
MPCVD machines can make diamond coatings, which are crucial to military sensor and detector applications due to their resistance to scratching, high thermal conductivity and water repellency. In 2019, AKHAN Semiconductor, a technology startup in the US, said it would use its diamond coating technology in Lockheed Martin’s weapons.
Currently, Chinese MPCVD machine makers include Wattsine, Uniplasm, Newman-hueray Microwave Tech. Global players include WEC Superabrasives in Taiwan, Seki Diamond Systems in the US and Iplas GmbH in Germany.
In August 2023, China imposed export restrictions on gallium and germanium. Gallium is used in compound semiconductors, which are often used to improve transmission speed and efficiency in radars. Germanium is used in night-vision goggles and the solar cells used to power many satellites.
China controls about 80% of the world’s gallium supply and 60% of germanium, according to European industry association Critical Raw Materials Alliance (CRMA).
However, some researchers said last October that there weren’t any signs of shortages of the two minerals on the global markets.
Read: China racing to stockpile AI-powering HBM chips
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