Ganfeng Lithium Co Ltd has filed for a Hong Kong stock market flotation, betting on a rise in demand for lithium as electric cars become more mainstream.
The move threatens to jolt China's exports of aluminium, which have been booming in recent months. Mexico "is a big market" for Chinese aluminium foil.
RTB Bor copper mining and smelting complex was crucial for the country before the collapse of communist Yugoslavia. However, it later became a burden on the country’s struggling economy because of malpractices and international sanctions.
In July, Belgrade invited bids for a partner to invest at least $350 million in debt-laden RTB Bor but did not say how big a stake it would offer in return.