A brief survey of the history of development, production, and uses of advanced Martenite-type refractory materials for repair and maintenance of the bottom lining of open-hearth and electric-arc furnaces is given.The chronicle concerning the development of materials for repairing the bottom lining of open-hearth furnaces dates back to the land-lease times. The progress achieved by American designers in the production and uses of unshaped refractories -Basifrite, Magnifrite, Ramix, Thomasite, etc.-was a stimulus for researcher in the Soviet Union to develop analogous domestic materials.The basic technology for a fast-sintered "metallurgical" powder (coined Martenite) was developed at the All-Russia Research Institute for Refractories (city of Kharkov) in 1945 -1946 . In 1946, at the Chasov-Yarskii refractory plant, an industrial-scale pilot batch of Martenite powder was made by a technology combining pelletization and sintering of ground materials [1]. The recommended composition of the mixture for preparation of the Martenite powder was (with allowance for the standard requirement of 68 -70% periclase and 10 -15% calcium ferrites in the end product), %: MgO, about 70; CaO, about 15; Fe 2 O 3 , about 10, and SiO 2 , not higher than 5. The raw materials used were: caustic (calcined) magnesite or finely ground magnesite powder, limestone, iron ore, and phosphorite.The starting materials were co-ground in a tube mill, and the mixture was pelletized and sintered using a tunnel furnace. The sintered pellets were crushed into fractions in size smaller than 12 mm. The powder thus obtained was of composition, wt.%: MgO, 62.3 -72.2; CaO, 11.1 -14.4; Fe 2 O 3 , 9.0 -11.9; SiO 2 , 3.5 -5.0; Al 2 O 3 , 0.9 -3.3, and P 2 O 5 , 0.36.It was shown in [2] that, using a synthetic material containing a low-melting phase (10 -20% calcium ferrites or brownmillerite), one can provide conditions for the fast sintering of the furnace bottom without detriment to its resistance to attack by molten metal and slag.In April 1946, a decision of the Ministry of Ferrous Metallurgy of the USSR was taken to start production of this material. In 1953, a shop was organized at the Magnezit Works for production of the Martenite-grade powders by a technology that included the preparation of a slurry of caustic magnesite, dolomite, and siderite ore followed by the calcinations of the slurry in a rotary kiln. Over the starting and adjustment period, more that 3000 tons of Martenite powder have been produced [3]; batches of it were sent for testing at the Serov, Chelyabinsk, and Zlatoust metallurgical works. The Martenite powder was used to repair the bottom lining of an open-hearth furnace, exploiting a layer-by-layer coating technique. The method proved to be easy to handle; it provided good sintering and allowed one to save hot repair time.In 1960 -1961, at a high-refractory materials laboratory headed by V. A. Bron (Eastern Research and Design Institute for Refractory Industry (VestIO), Ekaterinburg, Russia), the properties of magnesite powders (avai...
