Study On Dephosphorization Of High-phosphorus Iron Ore By Oxygen-rich Top-blowing Smelting Reduction Ironmakin

High phosphorus iron ore is abundant in China,but its composition is complex and phosphorus minerals are fine dispersed.So the dephosphorization rate of mineral processing and smelting is very low,and ore resources can not be fully exploited and utilized.At present,the process of sintering and smelting of blast furnace ironmaking has no dephosphorization function,and phosphorus entering into molten iron seriously affects the properties of steel and increases the brittleness of iron and steel.The oxygen top-blown smelting reduction ironmaking technology is non blast furnace ironmaking,which can realize dephosphorization in the smelting process.So the research and development of this new technology has important significance to fully exploit and use of high phosphorus iron ore rich resources.In the paper,the composition of the ore,the occurrence state and the distribution characteristics of the the Huimin high phosphorus iron ore in Yunnan were analyzed.Based on the above analysis,we studied the phosphorus 0.9%Huimin high phosphorus iron ore using the oxygen top-blown smelting reduction ironmaking dephosphorization technique,anylyzed the reaction mechanism of multiphase reaction,the influence of the activity of metal and slag component on the distribution and direction of phosphorus in the oxygen top-blown smelting reduction furnace.The main conclusions are as follows:?1?When the compound dephosphorization agent is used,the alkalinity is 2.5,the oxygen enrichment is 48.6%,the reduction temperature is 1550?and the reaction time is 60min and C/O=1.1,the yield of iron is 95.35%,the content of phosphorus in molten iron is 0.11%and the dephosphorization rate is up to 95.64%.This parameter is the best process parameters of high phosphorus iron ore oxygen top blown smelting reduction ironmaking dephosphorization,and the suitable slag system is CaO-SiO₂-Al₂O₃.?2?In the process of dephosphorization of high phosphorus iron ore,the behavior of sulfur and carbon in iron ore will have a certain effect on dephosphorization.Because of the need for simultaneous desulphurization,the alkalinity will be increased.Because of the need to maintain a low carbon,the temperature can't be too high.With the increase of alkalinity,the sulfur in the pig iron decreases first and then increases,and the carbon content decreases.With the increase of oxygen enrichment,the content of sulfur in the molten iron increases and the carbon content is reduced.When the reaction temperature is less than 1550?,the desulfurization reaction is comparatively thorough,and the desulfurization rate is higher,up to 83%.When the temperature is more than 1550?,the desulfurization rate is not changed much.The carbon content increases with the increase of temperature.At 1600?,the carbon content can reach 0.3%.?3?Simulation research of the oxygen top blown smelting reduction furnace shows hat the temperature field,velocity field and concentration field of the smelting reduction furnace are strongly stirred by the top oxygen lance and the side material spray gun,and form a severe phenomenon of"Fountain",which strengthens the flow and heat transfer in the smelting reduction furnace.?4?The test results on the 1000kg/d high phosphorus iron ore oxygen top blown melting reduction ironmaking dephosphorization device shows that the hosphorus content of iron water is 0.17%,and the dephosphorization rate is up o 89.09%in the high phosphorite with 0.972%phosphorus.