HARARE (Reuters) - Four lithium mining companies have tabled plans to produce battery-grade lithium in Zimbabwe, a government official said on Monday.

Zimbabwe, Africa's top producer of lithium, which is used in electric vehicle batteries and to store renewable energy, is prodding miners to refine the mineral locally as it hopes to boost its economy.

Currently, Chinese lithium miners, who dominate the sector in Zimbabwe, only produce lithium concentrates which they ship to China for further processing.

Last November, Zimbabwe's finance minister Mthuli Ncube said the government had given miners up to March 2024 to submit plans on refining within the country.

The government had extended the deadline by two months at the request of some miners, deputy mines minister Polite Kambamura told Reuters.

"They are coming forward with plans but these are long term plans which we are receiving. We have four large scale producers who have come forward," Kambamura said.

He declined to name the firms which have submitted plans, but added that government has yet to consider the proposals.

Zimbabwe's hard-rock lithium reserves, some of the world's biggest, have attracted over $1 billion of investment from Chinese miners including Zhejiang Huayou Cobalt Sinomine Resource Group, Chengxin Lithium Group, Yahua Group, Canmax Technologies and the Tsingshan Group.

Huayou has said it would explore production of battery-grade lithium in Zimbabwe "only when the construction and economic conditions are right".

The company says Zimbabwe lacks resources needed to produce battery-grade lithium, including reliable renewable energy, natural gas and sulphuric acid.

Zimbabwe has, however, insisted on local refining as it seeks to capitalise on projected growth in lithium demand as the world shifts to cleaner energy sources.

"We are not going to end on concentrates, we want batteries to be manufactured here," Kambamura said.

(Reporting by Nyasha Chingono; Editing by Nelson Banya and Franklin Paul)

By Nyasha Chingono