(中南大学 资源加工与生物工程学院,长沙 410083)
摘 要: 开发一种处理高铝褐铁矿的新工艺。采用钠化还原−磁选法对一种铁品位为48.92%(质量分数)、Al2O3含量为8.16%(质量分数)的高铝褐铁矿进行铝铁分离研究。结果表明:当硫酸钠添加量为12%(质量分数),还原焙烧温度为1 050 ℃,焙烧时间为60 min时,焙烧产物磨至粒度小于0.074 mm的占98%;在磁场强度为0.675 T的条件下,可获得铁品位91.00%,Al2O3含量1.36%的金属铁粉,铁的回收率为91.58%,铝的脱除率为90.47%。XRD研究结果表明,在钠盐焙烧过程中,铁氧化物被还原成金属铁,大部分铝、硅矿物与硫酸钠反应生成非磁性物质铝硅酸钠,经磁选后进入非磁性物,从而实现铝铁的高效分离。
关键字: 褐铁矿;钠盐;铝;还原焙烧;磁选
(School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China)
Abstract:A novel process was developed to treat the high-aluminum limonite ores. Al-Fe separation from a high-aluminum limonite ore with total iron grade of 48.92% and Al2O3 content of 8.16% (mass fraction) was studied by reduction roasting with addition of sodium salt followed by magnetic-separation. The results show that metallic iron powder with total iron grade of 91.00% and Al2O3 content of 1.36% is obtained when the sodium sulfate dosage is 12% (mass fraction), the roasting temperature is 1 050 ℃ and time is 60 min, and the grinding fineness is 98% ores less than 0.074 mm and the magnetic field intensity is 675 mT, then the iron recovery is 91.58%, and the removal of Al2O3 is 90.35%. The XRD results indicate that the iron oxides are transformed into metallic iron, most of the aluminiferous mineral and silicic mineral reacts with the sodium sulfate during the reduction roasting and forms sodium aluminosilicates, which enter into the nonmagnetic materials during the magnetic separation, then Al-Fe separation is realized.
Key words: limonite ores; sodium salt; aluminum; reduction roasting; magnetic separation