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对典型钛铁矿的化学成分、物相组成和表面结构进行表征,X射线衍射(XRD)分析其结果表明,钛铁矿中主要的物相成分为FeTiO_3。根据钛铁矿的成分特点,采用还原焙烧-盐酸加压浸出法对钛铁矿进行浸出制备人造金红石,研究了预焙烧处理对于铁元素价态及浸出效果的影响。结果表明,弱氧化焙烧和还原焙烧均能够改善钛铁矿的理化性能,强化其浸出效果。最佳的预处理方式为还原焙烧,还原剂用量为8%,焙烧温度900℃,焙烧时间60 min。对于还原焙烧后的钛铁矿进行盐酸加压浸出研究,考察了浸出温度、浸出时间、盐酸浓度、液固比等因素对浸出效果的影响。盐酸加压浸出的最优条件为:浸出温度140℃,浸出时间4 h,盐酸浓度20%,液固比9∶1。此条件下得到的浸出渣煅烧所得金红石TiO_2含量可达93.45%。该工艺流程比较简单,能够有效地实现钛铁矿中杂质的分离,获得高品位的人造金红石产品。
The chemical composition, phase composition and surface structure of typical ilmenite were characterized by X-ray diffraction (XRD). The results show that the main phase composition of ilmenite is FeTiO_3. According to the characteristics of ilmenite, man-made rutile was prepared by leaching ilmenite by reduction roasting-hydrochloric acid pressure leaching method. The effects of pre-roasting treatment on valence of iron and leaching effect were studied. The results show that the weak oxidation roasting and roasting can both improve the physical and chemical properties of ilmenite and enhance its leaching effect. The best pretreatment method is reduction roasting, the dosage of reductant is 8%, the roasting temperature is 900 ℃ and the roasting time is 60 min. Hydrolytic leaching of ilmenite after reduction roasting was studied. The effects of leaching temperature, leaching time, hydrochloric acid concentration, liquid-solid ratio and other factors on the leaching effect were investigated. The optimal conditions for pressure leaching of hydrochloric acid were leaching temperature of 140 ℃, leaching time of 4 h, hydrochloric acid concentration of 20% and liquid to solid ratio of 9:1. Under these conditions, the leaching residue obtained by calcination of rutile TiO 2 content up to 93.45%. The process is relatively simple, can effectively achieve the ilmenite impurity separation, access to high-grade synthetic rutile products.