Flash smelting (Finnish: Liekkisulatus) is a smelting process for sulfur-containing ores including chalcopyrite. The process was developed by Outokumpu in Finland and first applied at the Harjavalta plant in 1949 for smelting copper ore. It has also been adapted for nickel and lead production. The reactions in the flash smelting furnaces produce copper matte, iron oxides and sulfur dioxide. The reacted particles fall into a bath at the bottom of the furnace, where the iron oxides react with fluxes, such as silica and limestone, to form a slag. INCO was acquired by Brazil's Vale in 2006.