Research On Magnetic Roasting-magnetic Separation Technology Of Refractory Iron Ore Of Jiuquan Steel

Utilizing shaft furnace magnetization roasting process of Jiusteel has a problem that iron recovery rate of lump ore is low and the powder ore is difficult to utilize. It needs to develop a new iron ore processing technology. After studied the basis of physical and chemical properties of material, this paper systematical study pelletizing, drying,magnetization roasting and magnetic separation process of Jiusteel’s Jingtieshan and Baijian original ore powder through the laboratory simulation, discover:The appropriate parameters of Jing Tie Shan original ore pelletizing process are as following: the ratio of bentonite is about 2%, the ratio of pulverized coal is 2% or so, the proportion that the granularity of original mineral powder less than 200 mesh control in80%, moisture control around 9.5%. To satisfy the need of original ore pellets magnetization roasting, control the pellet seam thickness at 200 mm, drying air velocity about 1 m/s, drying air temperature about 300℃, drying time in 10 minutes during the raw pellets drying process. Magnetize roast Jingtieshan ore pellets 40 minutes with high temperature reaction tube under 800℃ isolated from air atmosphere(neutral). Natural cool under nitrogen from the air after magnetization roasting. Then the magnetized and roasted pellets use twice grinding and twice magnetic separation process. It can be obtained iron concentrate that TFe is 61.86%.The rate of iron concentrate reached52.10% and the recovery rate of TFe is 85.07%.The appropriate parameters of Baijian original ore pelletizing process are as following: the ratio of bentonite is about 2%, the ratio of pulverized coal is 2% or so, the proportion that the granularity of original mineral powder less than 200 mesh control in a range 60%~80%, moisture control around 9.5%. To satisfy the need of original ore pellets magnetization roasting, control the pellet seam thickness at 200 mm, drying air velocity about 1 m/s, drying air temperature about 300℃, drying time in 10 minutes during the raw pellets drying process. Magnetize roast Baijian ore pellets 40 minutes with high temperature reaction tube under 800℃ isolated from air atmosphere(neutral).Natural cool under nitrogen from the air after magnetization roasting. Then the magnetized and roasted pellets use twice grinding and twice magnetic separation process.It can be obtained iron concentrate that TFe is 59.03%.The rate of iron concentrate reached 42.33% and the recovery rate of TFe is 74.54%.