中国有色冶金

Aiming at the difficulty of producing low phosphorus molten iron in the existing smelting process of high phosphorus oolitic hematite, the oxygen-rich side-blown reduction smelting technology of high phosphorus oolitic hematite to produce low phosphorus molten iron was proposed based on raw material analysis, thermodynamic calculation, reduction smelting test and reduction system balance calculation. The following conclusions were obtained.Mineral analysis showed that high phosphorus hematite has a typical oolitic structure, and hematite was mainly distributed in the shell of concentric ring wrapping structure formed with gangue minerals, which was not conducive to the physical separation of iron oxide and gangue. Thermodynamic analysis shows that at 1450~1600℃, phosphorus elements in the high phosphorus oolitic hematite can be reduced in the form of elemental phosphorus and enter the metallic iron phase, but cannot be volatilized in the form of phosphorus oxides. Only in the presence of CaO, H₂O and CO₂ reacted with Fe₃P to bring phosphorus into the slag in the form of Ca₃(PO₄)₂. The reduction smelting test showed that the phosphorus content in molten iron produced by the thermal furnace was greater than 1.0%, while the side-blown furnace was reduced to 0.45%. The equilibrium calculation showed that the recovery of Fe decreased with the increase of O₂/CH₄ and the decrease of carbon ratio; w[C] in molten iron decreased with w[P] in molten iron. This study showed that the oxygen-rich side blowing reduction smelting technology had the advantages of the strong performance of molten pool stirring, oxygen potential regulation and temperature control, which strengthened the smelting conditions of phosphorus removal in iron and phosphorus retention in slag, so as to realize the efficient and short process treatment of phosphate-bearing iron base minerals. This paper can provide theoretical basis and process parameter guidance for the industrial application and promotion of oxygen-rich side-blown reduction smelting of high phosphorus oolitic hematite.