Effects of reductants on the reduction roasting and Fe-P separation of high phosphorus oolitic hematite

Abstract

The effects of reductant type and dosage on the reduction roasting and Fe-P separation of high phosphorus oolictic hematite were studied in this paper. Experimental results show that,with addition of Na2CO3 as a dephosphorization agent,the iron content increases,the phosphorus content decreases in direct reduced iron,and the sulfur content can be decreased at the same time.Iron reduction is promoted by increasing the reductant dosage,but reductants with higher ash and fixed carbon contents or a lower volatile content do not favor dephosphorization. X-ray diffraction analyses of roasted products indicate that Na2CO3 as a dephosphorization agent is added in reduction roasting,the content of metallic iron increases but the contents of wustite and quartz decrease with increasing reductant dosage. When using a reductant with a higher ash content,Na2CO3 can be consumed by the ash with increasing reductant dosage,thus its promotion to iron reduction weakens. At the same reductant dosage,the highest content of metallic iron in roasted products is obtained by using stone coal as a reductant,followed by bituminous coal,coke and lignite,and the content of wustite in roasted products gradually decreases. As a whole,there is the best Fe-P separation effect in this iron ore treatment by using lignite as a reductant,followed by bituminous coal,coke and stone coal.

Keywords

• hematite
• iron ore treatment
• direct reduction
• roasting
• phosphorus removal