本文選題：高磷鮞狀赤鐵礦　切入點：煤泥　出處：《北京科技大學》2017年博士論文

【摘要】：高磷鮞狀赤鐵礦是公認難選的鐵礦石類型之一。近年來研究表明,采用煤基直接還原焙燒-磁選工藝可有效處理該類礦石。煤泥是選煤過程中產(chǎn)生的一種副產(chǎn)品,因為它具有水分含量高、粘性大、灰分含量高的缺點,所以較難被利用。高爐灰是鋼鐵工業(yè)的副產(chǎn)品,具有既含碳也含鐵氧化物的特點,但因無行之有效的利用途徑,大部分被室外堆存,既造成了環(huán)境污染也造成了鐵資源的浪費。本文研究了煤泥和高爐灰作為高磷鮞狀赤鐵礦直接還原焙燒中還原劑的可行性�？疾炝瞬煌N類的煤泥在高磷鮞狀赤鐵礦直接還原焙燒中的作用及機理,并獲得了最佳工藝條件。結果表明,煤泥T的還原效果最好,在其用量為20%時可獲得鐵品位為91.35%,鐵回收率為81.13%,磷含量為0.076%的還原鐵產(chǎn)品。高爐灰與高磷鮞狀赤鐵礦共還原是可行的,既利用了高爐灰中的碳,也同時回收了高爐灰和高磷鮞狀赤鐵礦中的鐵,實現(xiàn)了高爐灰和高磷鮞狀赤鐵礦共同利用的目的。通過對脫磷劑用量、焙燒時間、焙燒溫度、高爐灰用量的研究,獲得了最佳工藝條件。結果表明,在高爐灰用量為30%,焙燒溫度為1150℃,焙燒時間為60min的焙燒條件下,焙燒產(chǎn)品經(jīng)兩段磨礦-磁選,可獲得鐵品位92.16%,鐵回收率87.89%,磷含量0.072%的還原鐵產(chǎn)品。同時發(fā)現(xiàn)脫磷劑CaCO_3可以降低還原鐵產(chǎn)品的磷含量,Na_2CO_3可以提高鐵回收率。發(fā)現(xiàn)高爐灰在C/Fe比為1.04已可以完成與高磷鮞狀赤鐵礦的共還原,并且發(fā)現(xiàn)在高爐灰作為還原劑時焙燒效果優(yōu)于煤的。用X射線粉晶衍射、掃描電子顯微鏡及能譜分析對煤泥和高爐灰在高磷鮞狀赤鐵礦直接還原焙燒過程中的作用機理進行了研究。.發(fā)現(xiàn),煤泥灰分中的石英在還原氣氛充足時對氟磷灰石的還原具有促進作用,結果導致還原鐵產(chǎn)品中的磷含量升高。煤泥中的揮發(fā)分在還原過程中起作用,能夠提高還原鐵的鐵回收率,但對降低還原鐵產(chǎn)品中的磷含量不利。引入C/Fe比的概念,查明了高爐灰在共還原焙燒中的反應機理,即高爐灰與高磷鮞狀赤鐵礦更易發(fā)生固相-固相反應,而煤在此條件下更易發(fā)生氣相-固相反應。固相-固相反應有利于提高鐵回收率和降低還原鐵中的磷含量,而氣相-固相反應則不利于降低還原鐵中的磷含量。
[Abstract]:High phosphorous oolitic hematite is recognized as one of the difficult iron ore types. Recent studies have shown that coal based direct reduction roasting and magnetic separation process can effectively treat this kind of ore. Coal slime is a by-product of coal preparation process. Because of its high moisture content, high viscosity and high ash content, blast furnace ash is difficult to be used. Blast furnace ash is a by-product of iron and steel industry and has the characteristics of both carbon and iron oxides, but it has no effective way to use it. Most of it is stored outdoors, This paper studies the feasibility of coal slime and blast furnace ash as reducing agent in direct reduction roasting of high phosphorous oolitic hematite. The role and mechanism of direct reduction roasting of iron ore. The optimum technological conditions are obtained. The results show that the reduction effect of slime T is the best. Iron grade is 91.35, iron recovery rate is 81.13 and phosphorus content is 0.076%. Co reduction of blast furnace ash with high phosphorous oolitic hematite is feasible. At the same time, the iron from blast furnace ash and high phosphorous oolitic hematite was recovered, and the purpose of co-utilization of blast furnace ash and high phosphorous oolitic hematite was realized. The amount of dephosphorization agent, calcination time, calcination temperature and amount of blast furnace ash were studied. The optimum technological conditions are obtained. The results show that under the conditions of 30% ash content, 1150 鈩，

本文編號：1664718