It's renowned for being one of the worst acquisitions in corporate history, but the business that emerged from Rio Tinto's $US38 billion acquisition of Alcan is starting to win back some respect.

Having worn close to $US30 billion ($38.5 billion) of impairments over the past decade, that 2007 acquisition will never be considered a success, but that hasn't stopped some quiet optimism emerging as China's role in the production of the lightweight metal evolves.