Research On The Dephosphorization From High-phosphorus Iron Ore During Sintering

Development and utilization of low cost composite paragentic iron ore for the steelenterprises is an effective strategy to respond the increasing prices of foreign orecurrently. In the western part of Hubei there is a huge mineral deposit of high-phosphorushematite; however, the iron ore can not be directly used in the iron and steel enterprisesbecause of the high phosphorus content. Therefore, for this type of ore, its mineralcomposition and microstructure have been mainly investigated, and on the basis ofthermodynamic principle HSC is used to develop dephosphorization agent, and thenmini-sintering method is adopted to study the effect of dephosphorization agent content,carbon content, basicity, temperature and other factors. The main contents andconclusions are described as the followings:1)The main minerals in the high-phosphorus hematite are hematite, chlorite, quartzand dolomite. The quantity of apatite is minor in these iron ore.The apatite and hematiteores are composite paragentic relationship and can form the oolitic structure of ring andinterphase.2)The main component of dephosphorization agent are CaCl₂, MO and C₆H₁₂O₆.3)It is studied that the dephosphorization agent affect the gasificationdephosphorization of the high-phosphorus hematite by the mini-sintering. the rate ofgasification dephosphorization is optimum, when the proportion of CaCl₂, MO andC₆H₁₂O₆in dephosphorization agent is2:1:3.2and dephosphorization agent is2.31%inthe sintered mix material. In addition，the maximum value for17.5%is obtained, whenthe temperature is1250℃, the basicity is1.8, carbon content is3.5%and the particleranges from0.15mm to0.18mm，with adding dephosphorization agent.4)It is studied that carbon content, basicity, temperature and particle affect thegasification dephosphorization of the high-phosphorus hematite by the mini-sintering.The carbon content has a optimal value for3%; basicity and particle are in favor ofgasification dephosphorization in the case of the smaller particle, but considering theactual situation, basicity is1, particle ranges from0.074mm to0.096mm, temperature isin favor of gasification dephosphorization in the case of higher temperature, but low-temperature sintering is advocated in the sinering, and the temperature is1300℃. whenthe condition is optimum, the rate of gasification dephosphorization is36.7%.The phosphorus of the high-phosphorus hematite can be reduced effectively throughmini-sintering method. The research work can provide theoretical evidence for high-phosphorus hematite to directly use the sinter in the future.