A century of processing of fine grained iron ores in Norway

This is an important part of the Norwegian technological history. The larger Norwegian iron ore deposits have generally been of a low grade 33- 35 % Fe and a fine grained texture. Large scale utilisation was therefore out of question most of the 19th century. The developments in fine particle processing and electromagnetic technology that took place after year 1870, made the deposits attractive to foreign investors, because the supply of direct smelting ores was limited. This paper will deal with the technical evolution of iron ore processing in Norway, which is interesting because it included pioneering use of fine particle processing technology as soon as it became available. Finally the paper deals with the shift from blast furnace feed to alternatively better paid iron oxide products with stricter quality requirements as competition with an abundant supply of direct smelting ores from deposits in countries like Brazil and Australia became too strong after 1970.