Hm ... I strongly suspect that the link to RioTintoAlcan is a mistake of this business information webpage. Studying RioTintoAlcan's homepage there is no RioTintoAlcan dependance, division or production site located in Gttingen/Germany.
To enlight this I did a little research and found this:
1902 - The Canadian „Northern Aluminum Company Limited“ was founded (a daughter-company of the US "Alcoa Inc.")
1925 - Renaming to „Aluminum Company of Canada Limited“ (since 1945 registered as "Alcan", but I use this short term here now)
1928 - Alcan seperated from "Alcoa Inc." and became an independent company
1930 - The rolling mill in Gttingen/Germany became part of Alcan (I found no information if the plant was founded then or if it had been a former owner)
... a long period less of information ...
2000-2003 - Alcan tookover some European aluminium-companies and became a monopolist, therefore the European Cartel Office decided that the group had to be divided
2005 - To accomplish this, Alcan's rolling mills transfer into an independent company called "Novelis Inc." (the headquarter changed from Toronto/Canada to Atlanta/USA)
2007 - Alcan itself is taken over by the Anglo-Australian mining group Rio Tinto and is now called "Rio Tinto Alcan"
2007 - Novelis Inc. - burdened with the debts of the old Alcan - was sold to the Indian company "Hindalco Industries Ltd." and is therefore part of the Aditya Birla Group, an Indian company conglomerate
The Novelis Deutschland GmbH - Novelis Inc.'s daughter in Germany - owns the factories/mills in Gttingen, Nachterstedt, Berlin, Plettenberg-Ohle and Ldenscheid.
Researching companies history is dry work, but after this it seems that Mr. T must update his files a little ;-)
If desired, I can specify the homepages with all information given here.