Technological Solutions for Intensive Production of Low Silicon Hot Metal in Blast Furnace
Production of low silicon hot metal is an essential part of successful treatment of vanadium containing titania-magnetite ore in blast furnace. The formation of titanium carbides and titanium nitrides very much depends on solubility of titanium in hot metal. The analysis showed that with reduction in silicon content the content of titanium in hot metal is also reduced.
Similarity in silicon and titanium reduction allows usage of the sam factors to control content of these elements in hot metal. Increase in furnace pressure reduces silicon and titanium content in hot metal and first of all titanium-carbide formation. At actual blast furnace conditions the content of titanium carbides is far from equilibrium and materials residence time is an important control parameter. Increase in coke strength after reaction (CSR) improves permeability of coke packing and accelerates filtration of the melt, suppressing titanium-carbides formation. Increase in hearth’s height to width ratio with the same hearth’s volume also positively affects operation of blast furnace.
Uniform descent of pellets and sinter, and uniform distribution of limestone in furnace cross-section stabilize the heat transfer conditions further suppressing formation of titanium-carbides.
The practical measures to retard titanium-carbides formation and to produce high quality low silicon and low titanium hot metal are proposed and implemented at Nizgny Tagil I & S Works in Russia (NTMK) with increase in blast furnace specific productivity up to 3.5 thm/m3/day.