(p96) Advance in Technology and Practice of Titania-Magnetite Ore Processing

摘要

Titania-magnetite ores represent a largely untapped resource for international steelmakers in spite of representinga significant percentage of the Earth's available iron. Recent developments in titania-magnetite ore processingtechnology in blast furnace have made them economically viable. The analysis showed that with reduction in siliconcontent the content of titanium in hot metal is also reduced. Similarity in silicon and titanium reduction allows usageof the same factors to control content of these elements in hot metal. A method for estimation of interdependencyof intensity of titania-magnetite blast furnace operation and indirect reduction was developed. It was shown thatreduction in specific coke consumption and productivity increase can be achieved when efficiency of CO utilizationis close to the equilibrium. Technical and economical performance of the blast furnace can be further improved byincrease in oxygen enrichment. The following improvements also contribute into increase in intensity of blastfurnace operation: improved sinter screening, increase in operating pressure, elimination of limestone from thefurnace burden and improvement in coke quality and size distribution. Uniform descent of pellets and sinter, anduniform distribution of limestone in furnace cross-section stabilize the heat transfer conditions further suppressingformation of titanium-carbides. Influence of natural gas and pulverized coal injection on titania-magnetite blastfurnace operation is evaluated. As a result blast furnaces of EVRAZ-NTMK operate with specific productivity of 3.4-3.6 thm/m3(wv)/day) while titania load is 45-50 kg/thm.