The major miner said in a statement on Friday it had reviewed its links to Rusal, principally through its 20% holding of the Queensland Alumina refinery, and would have to break some supply contracts.
"As a result of the imposition of these sanctions, Rio Tinto is in the process of declaring force majeure on certain contracts and is working with its customers to minimise any disruption in supplies," the company said.
Rio also said it sold bauxite to Rusal's refinery in Ireland and bought alumina for its own refineries in France and Iceland.
The US sanctions on Deripaska were punishment for Russia's recent actions on the world stage, as he is considered close to the Kremlin.
The announcement came after the ASX had closed and half an hour from the bell in London.