BEIJING, Dec 26 (Reuters) - China's Tongwei plans to invest 28 billion yuan ($3.9 billion) to expand its silicon production capacity, it said on Tuesday of the raw material used in photovoltaics.

Tongwei plans a project in Ordos city in north China's Inner Mongolia with total annual production capacity of 500,000 metric tons of industrial silicon and 400,000 tons of polysilicon, the company said in a filing to the Shanghai Stock Exchange.

The investment will enable Tongwei, the world's biggest producer of polysilicon, to fully utilise the rich natural resources in Inner Mongolia, the company said, adding that the project will not have a material impact on revenue and net profit in 2023 and 2024.

About 13 billion to 14 billion yuan will be invested in the first phase of the project, with annual capacity of 200,000 metric tons of industrial silicon and 200,000 tons of polysilicon, the statement said.

The company aims to have the first phase operational by the end of 2025, with the start of the second phase dependent on market conditions, it said.

Shares in Tongwei rose by nearly 0.2% to 23.74 yuan on Tuesday. The most-traded February industrial silicon contract on the Guangzhou Futures Exchange closed daytime trading 0.25% down at 14,235 yuan a ton.

($1 = 7.1461 Chinese yuan) (Reporting by Amy Lv and Andrew Hayley Editing by David Goodman)