BEIJING - China's export controls on three metals important across the defence and chip sectors are keeping shipments at historically low levels despite high prices worldwide as Beijing flexes its control over the minerals supply chain.

China is the world's largest producer of antimony, germanium and gallium, which have niche but vital roles in clean energy, chipmaking and defence. Since 2023, Beijing has gradually added the metals to its export controls list. In December it banned exports to the US.

For any item on the control list, exporters must apply for licenses, an opaque process which allows Beijing to exert the dominance it has built for years over the mining and processing of important minerals.

Fresh customs data released on Sunday reinforced a pattern building since controls were imposed: exports are down and some buyers, especially in Europe, are cut out of the supply chain.

Exports of antimony and germanium products in the first quarter were down 57% and 39%, respectively, compared to a year earlier.

March exports of gallium hit their lowest level since October 2023. Quarterly shipments were up on last year, but the current trend is still well below 2022, the last full year before curbs.

Minerals that are exported, in the case of antimony, are going to a smaller set of countries.

After a five-month hiatus, small shipments of antimony were sent to Belgium and Germany in March, but exports were well below historic levels and former large buyers like the Netherlands haven't received shipments since September.

The pattern across the three metals raises questions about how many export licenses China will approve for the seven rare earth elements it added to the control list this month - and how fast. Exporters say they expect to wait months for licenses and even longer if selling to the United States.

There have been no antimony exports to the United States since September last year and none since 2023 for germanium and gallium.

Fewer exports from China have left overseas consumers scrambling to source material, pushing prices higher, which in turn has supported prices in China.

Chinese spot prices of antimony, for example, have jumped by nearly two thirds so far this year to a record high of 230 000 yuan ($31 509) a ton on April 18, LSEG data showed.