煤种对钛磁铁矿直接还原-磁选钛铁分离的影响

研究了烟煤和无烟煤对海滨钛磁铁矿直接还原-磁选钛铁分离的影响机理.结果表明,在试验用量范围内,两种煤对还原铁指标的影响规律相近,煤用量低时钛磁铁矿还原不充分.随煤用量增加,被还原的金属铁越来越多,但粒度较小,与其他颗粒嵌布紧密,因此还原铁Fe品位低,Ti O2品位高,铁回收率则先提高后基本不变.所有煤用量下所得金属铁颗粒均纯净.和无烟煤相比,烟煤固定碳较低,还原气氛较弱,但灰分较高,有利于金属铁颗粒的聚集长大;因此相同用量的烟煤为还原剂时,焙烧矿中金属铁颗粒较少,但粒度较大,还原铁中Fe品位较高,铁回收率较低,Ti O2品位较低.

Effects of Coal Types on the Separation of Iron and Titanium in Titanomagnetite by Direct Reduction-Magnetic Separation

The influence of bitumite and anthracite on separation of Ti and Fe from beach titanomagnetite ore in the process of direct reduction-magnetic separation was investigated. The experimental results showed that the effects of bitumite and anthracite on iron reduction were similar during the range of experimental dosages. The reduction of titanomagnetite was insufficient when the coal dosages were not enough. With increasing dosages of coals， the quantity of reduced metallic iron increased in the roasted ore but the iron particles became smaller and were embeded closedly with other mineral particles， leading to low Fe grade， high TiO₂ grade in the product. The metallic iron particles obtained by reduction roasting under the experimental conditions were pure. Compared with the same dosages of anthracite， the reducing atmosphere obtained by using bitumite with less content of fixed carbon was weaker but higher ash content of bitumite was good for the growth of metallic iron particles. Hence， the quantity of metallic iron was less but size of particle was larger in the roasted ore. So the direct-reduction iron(DRI) obtained by bitumite had higher Fe grade， lower iron recovery and lower TiO₂ grade than that produced by anthracite.