In a filing to the Shenzhen Stock Exchange, the battery material maker said on Wednesday that three of its Hong Kong units signed agreements with a Singapore-based Rigqueza International Pte Ltd to jointly invest in the three projects in Weda Bay industrial park.

Each involves investment of $420 million and aims to produce nickel matte with 40,000 tonnes of nickel content per year via four production lines, the filing said.

Nickel matte is an intermediate product that can be processed into battery-grade nickel.

CNGR had already invested in two nickel matte projects with Rigqueza last year in the Indonesian island of Sulawesi, with total annual capacity of 60,000 tonnes. The company also reached agreement with nickel giant Tsingshan Holding Group, which will supply it with 40,000 tonnes of the product.

"Both parties are continuously optimistic about the nickel matte industry," CNGR said in the statement, adding that the investments are expected to further secure company's resources and lower the costs of producing battery materials.

Registered in Singapore, Rigqueza will own a 30% stake in each of the three new projects, CNGR said.

The Chinese company did not disclose more information about its partner, but said Rigqueza's main responsibilities included coordination with the Indonesian government, helping to secure local approvals and financing.

CNGR could not be contacted for further comment.

Nickel prices on the London Metal Exchange doubled to a record level of over $100,000 a tonne within an hour in March as Russia-Ukraine conflict fanned an already rallying market. They eased to around $26,365 per tonne on Tuesday.

(Reporting by Min Zhang in Beijing and Meg Shen in Hong Kong; editing by Barbara Lewis)

By Min Zhang and Meg Shen