German aluminium smelter Voerde Aluminium launched insolvency proceedings on Friday but said the business would continue to operate and it would seek to restructure.
The company, which produces around 115,000 tonnes of aluminium annually and has 410 employees, said it had hit liquidity problems because aluminium prices had fallen since July last year while production costs have risen it.
The smelter was sold by British group Corus in 2009 to BaseMet, owned in turn by investor Gary Klesch.
"I am confident that we will be able to find a suitable solution to continue operations which will be in the best interests of the company and creditors," Chief Executive Wout Kusters said in a statement.