An Investigation On Dephosphorization Of High Phosphorous Iron Ore By Biomass Reduation Roasting And Magnetization Of Pyrite Cinder

The iron ore is one of the most important raw materials of producing steel. With the rapid development of economy, our country's iron ore import volume increases year by year, but, in recent years, the rapid rise of international iron ore price has caused a lot of pressure to our steel corporations. Consequently, the active and effective development of our low grade and complex iron ore is very important to promote healthy and sustained development of our national economy.In this paper, dephosphorization and magnetic conversion of Hubei western high phosphorous hematite ore, quality improvement and impurity reduction from pyrite cinders were studied. In the experiment of magnetization and dephosphorization of high phosphorous hematite ore, biomass sawdust was used as reductant for magnetic reduction roasting of hematite ore, and then the technique of dynamic magnetic separation was used to recycle the iron ore concentrates. The effect of ore particle size, weight ratio of ore to biomass, roasting time, roasting temperature on magnetic conversion rate of hematite ore and dephosphorization rate were discussed in this experiment. A brief account of the fundamental mechanism of reduction was given by the method of the thermal analysis and X-ray diffraction. At the same time, the magnetic separation conditions such as stirring speed and magnetic separation time were investigated. Iron grade can reach more than 64.05%, dephosphorization rate reach more than 65.64% under the optimal technology condition which was determined as the amount of biomass at 20%,roasting temperature at 650℃for 40 min, stirring speed at 600 r/min for 40 min. In the experiment of iron improvement and impurity reduction from pyrite cinders, the technique of dynamic magnetic separation was used to recycle the magnetic iron. The effect of grinding fineness, magnetic field intensity magnetic separation speed, magnetic separation time and rinsing water flow rate were investigated. It was found that when grinding fineness under 74μm, magnetic field intensity at 700 mT, stirring speed at 100 r/min for 5 min, rinsing water flow rate at 2000 ml/min, the iron grade can reach more than 61.64%, iron recovery rate reach more than 80.86%, sulfur grade reach more than 0.53%.