The wholly-owned subsidiary of Masan Group said in a statement Tuesday the deal could expand its revenue three and a half fold to $4.6 billion.

The deal, whose value has not been revealed, is awaiting Vietnamese government approval, it said.

Masan Resources called the transaction "a strategic step" in executing its vision to become a leading vertically integrated high-tech industrial materials platform in the world as it moves into midstream tungsten products.   

Its midstream tungsten products will be used in various industries such as mechanical engineering, tool making, mining, automobile, energy, aviation, and chemicals.

H.C. Starck (HCS) is a global supplier of rare metals with production hubs in Europe, North America and China.

Masan Resources mines tungsten in the Nui Phao Mine in the northern Thai Nguyen Province. The mine has one of the world’s largest tungsten reserves outside China, an estimated 66 million tons.

A subsidiary of the company recently won a $130-million settlement from an Australian company over a construction deal following international arbitration.

Masan Group, one of Vietnam's largest private companies in terms of market capitalization, has interests in consumer goods, mining and banking.