The world's biggest iron ore producer Rio Tinto will raise $9 billion in U.S. investment-grade bonds as it seeks to fund its recently-closed buyout of Arcadium Lithium , the miner said on Wednesday.

Rio Tinto (NYSE:RIO) sold $9B of U.S. investment-grade bonds, as the miner raised funds for its recently-closed buyout of Arcadium Lithium, Bloomberg reported Tuesday. The debt was sold in eight parts,

Rio Tinto Group said it’s seeking to sell bonds in the US to help repay a bridging loan used to finance its $6.7 billion acquisition of Arcadium Lithium Plc.

A unit of the world’s second-biggest miner is looking to sell bonds in as many as eight parts, with the longest portion a 40-year note.

Australian mining group Rio Tinto has finalised the takeover of the lithium producer Arcadium from the USA, which was announced in October. The

Rio Tinto has completed its acquisition of Arcadium Lithium plc ("Arcadium Lithium") (NYSE: ALTM) (ASX: LTM) for $6.7 billion, following the sanctioning of the Scheme of Arrangement by the Royal Court of Jersey on 5 March.

Deal positions Rio Tinto among the world’s largest lithium miners, trailing only US-based Albemarle and Chile’s SQM.

The deal positions Rio Tinto as the ultimate parent company of Arcadium Lithium, now renamed Rio Tinto Lithium.