In the late 1840s, the German chemist  developed a modification of the puddling process to produce not iron but steel at the Haspe Iron Works in Hagen; it was subsequently commercialized in Germany, France and the UK in the 1850s, and puddled steel was the main raw material for Krupp cast steel even in the 1870s. Before the development of the basic refractory lining (with magnesium oxide, MgO) and the wide-scale adoption of the Gilchrist–Thomas process ca. 1880 it complemented acidic Bessemer converters (with a refractory material made of ) and open hearths because unlike them, the puddling furnace could utilize phosphorous ores abundant in Continental Europe.