The Experimental Research On Arsenic Removal And Iron-increase From Arsenic-bearing Limonite

The arsenic iron ore belong to refractory ire iron ore using arsenic steel.It willhave a series bad influence on steelmaking with the arsenic ore.Research on arsenicremoval from arsenic iron ore will have a very important significance to reduce theharm of arsenic in the system of steelmaking and achieve comprehensive utilization ofthe arsenic iron ore.On the basis of physicochemical properties and mineralogy characters of arestudied,through depth magnetic roasting-magnetic-roasting process deal with thearsenic iron ore of Hezhang,Guizhou.Getting the realization of ore grade increased andthe arsenic content of the ore down to the level of the blast furnace production.The test results shows that: when the magnetic roasting temperature is850℃,roasting time is40minutes,reducing agent is five percent (outside with), grindingfineness is-0.074mm accounted for97.51%,magnetic field strength is218.95kA/m,roasting temperature is1250℃, roasting time is25minutes,grade of iron concentrate63.2%and the recovery97.53%, arsenic concentrate of0.022%are obtained.Mechanism of the result shows that: magnetic roasting-magnetic concentrate ismainly composed of Fe3O4, γ-Fe2O3. It indicates that magnetic roasting-magneticseparation process can be good to improve the iron grade.The concentrate also containsa small amount of SiO2, As2Ni3O8and CaAl2Si2O8, which As2Ni3O8belong to arsenicminerals. It indicates magnetic roasting-magnetic separation process to removearsenic is not good. Roasting results show that the product is mainly composed ofFe2O3, followed Ca3Al2(SiO4)3and SiO2, a diffraction peak is almost not observed inthe arsenic containing substance, which indicate the majority of arsenic has beenremoved.