Main direction of the innovative improving of the blast furnace technologies – use of one type of iron raw material, combining the best properties of agglomerate and pellets

摘要

The known reserves of intensification and development of blast furnace technology are almost exhausted, which requires the search for new advanced technologies of improving the blast furnace smelting. One such area is the use of new types of iron ore in the blast furnace, without the shortcomings of traditional iron ore materials – agglomerate and pellets. Use of iron ore which will not only meet all the requirements of modern blast furnaces, but also does not require expensive re-equipment of agglomeration factories is an urgent task. Effective smelting of cast iron in blast furnaces necessitates the use of a uniformly fluxed and agglomerated iron-containing material – «local specs» obtained by the production technology of pellets with a high iron content and residual carbon, minimal silica content, high strength characteristics in cold condition, as well as during heating and reduction in a blast furnace. The developed technology makes it possible to obtain a uniform fluxed agglomerated material with high metallurgical characteristics. The research allowed to work out optimal charge composition for obtaining a mixture of high- and low-temperature pellets, their proportion, and thermohardening modes, making it possible to carry out the process both at high temperatures of heating and cooling, and in an atmosphere with a reduced oxidation potential as well to reduce carbon burnout and to protect the metallized part of the charge from oxidation. Comparative characteristics of technological production indicators and metallurgical properties of the produced agglomerated iron-ore materials (agglomerate and pellets) and the obtained agglomerated material show, that it has the best properties of traditional types of iron ore (granulometric composition, total Fe content, residual carbon content, basicity, strength characteristics in the cold state and during the reduction process, pressure drop of the layer during the reduction, shrinkage of the layer, final reduction degree and angle of repose), and also does not have their negative properties