MOSCOW, September 23 (RIA Novosti) - United Co. Rusal, the world's biggest aluminum producer, has filed an appeal against a Guinean court ruling that overturned its deal to buy the Friguia bauxite and alumina complex.

The Guinean government has told Rusal, controlled by Kremlin-friendly billionaire Oleg Deripaska, to return the Friguia facility to the government.

A Rusal source who requested anonymity told RIA Novosti the company was also "studying the possibility of taking the case to an arbitration court in Paris, since the 2006 Friguia privatization agreement falls under French jurisdiction."

The Guinean court ruling has drawn an angry reaction from Moscow.

The Russian Foreign Ministry said the court ruling was an "unlawful expropriation of property" and that the Guinean authorities "have, in effect, made an attempt to expropriate Rusal's property through the judicial process."

Rusal has protested the move, maintaining that it purchased Friguia in good faith and in compliance with Guinean laws.

The Russian company bought a 100% stake in the Friguia refinery from the state in 2006 and considers the plant to be its "legitimate property."

Guinea is the world's biggest exporter of bauxite, which is refined into alumina that is then processed into aluminum.

Friguia, one of Guinea's largest employers, produces about 52,000 metric tons of alumina a month.

Rusal accounts for 12% and 15% of global aluminum and alumina production, respectively. The company markets its products to 70 countries and employs a total 100,000 people in almost 20 countries.