Zimbabwe's first plant to process clean-energy metal lithium -- of which it is Africa's top producer -- is up and running, a milestone in its expanding drive to stop the wholesale export of its raw mineral wealth. Besides the focus on lithium, Zimbabwe has another 13 minerals on its list of "critical" minerals that cannot be exported in raw form from the start of next year.

The official state-owned lithium mining arm of Zimbabwe, Mutapa Energy Resources, has secured a $300 million investment to accelerate the development of its lithium assets,…

Zimbabwe wants to process more minerals at home, but smaller miners fear being left behind.