The Swedish company said the expansion at Harjavalta, the largest nickel smelter in the European Union, included a new concentrate dryer and increased capacity in the electric smelting furnace.

"The investment strengthens our productivity and competitiveness while further improving our already very strong environmental performance," Daniel Peltonen, head of Boliden's Smelters unit, said in a statement.

Boliden said Harjavalta was in a strong position to meet growing demand for nickel from the battery manufacturing sector for the automotive industry, among others.

(Reporting by Johannes Hellstrom; Editing by Simon Johnson)