还原剂对高磷鲕状赤铁矿还原焙烧铁磷分离的影响

摘要

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.%研究还原剂种类及用量对高磷鲕状赤铁矿还原焙烧铁磷分离的影响.添加脱磷剂Na2CO3,在提铁降磷的同时能降低还原铁的硫含量;还原剂用量的增加都能促进铁还原,但使用灰分和固定碳含量较高或挥发分含量较低的还原剂时,不利于降磷.焙烧产物的X射线衍射分析表明:添加脱磷剂Na2CO3时,随着还原剂用量的增加,焙烧产物中金属铁含量增加,浮氏体和石英含量降低;使用灰分含量较高的还原剂时,随其用量的增加,灰分会消耗Na2 CO3,从而减弱其对于铁还原的促进作用;还原剂用量相同时,石煤、烟煤、焦炭和褐煤所得焙烧产物中金属铁含量逐渐增加,浮氏体含量逐渐降低.总体来看,褐煤作为还原剂时铁磷分离效果最好,其次为烟煤,焦炭和石煤.