On the whole, however, blast furnace practice remains, except for minor details, comparatively unchanged over long periods, although practice in different countries varies widely.

The basic idea of a blast furnace dates back more than 2,000 years to 1st century China. The technology has been updated and the size of furnaces increased but the principle remains the same.

Modern blast furnaces use the basic oxygen process which dates back to 1940s Austria. Most of the world's steel is made by this method - 70% in 2011. ... Diagram of an arc furnace.