添加剂活化赤泥磁化焙烧⁃弱磁选回收铁

Magnetizing Roasting with Additive Activation and Low Intensity Magnetic Separation for Iron Recovery from Red Mud

为查明添加剂对赤泥磁化焙烧⁃弱磁选回收铁的影响,以某高铁高铝赤泥为研究对象,研究了焙烧、磁选制度对铁回收率的影响。结果表明,白云石和磷石膏对铁的回收无明显作用,而硫酸钠活化作用明显。较佳实验条件为:硫酸钠用量10%、焙烧温度650℃、焙烧时间90 min、总气体流量500 mL/min、CO体积分数30%、焙砂磨矿细度-0.045 mm粒级占比65%、磁场强度68.8 kA/m,此时可获得TFe品位和回收率分别为60.65%和94.01%的磁铁精矿。热力学分析结果表明,在研究温度范围内,白云石与磷石膏均有利于铁橄榄石的分解,而对铁尖晶石的分解不起作用,硫酸钠则可同时促进二者的分解。

In order to investigate the influence of additive on iron recovery from red mud by using a process consisting of magnetizing roasting and low intensity magnetic separation,a kind of red mud containing high content of iron and aluminum was taken for experiments.It is found that addition of dolomite and phosphogypsum won′t bring any effect to iron recovery,but sodium sulfate can bring an obvious activation effect.In the experiment,the roasting process ran at 650℃for 90 min,with the addition of sodium sulfate at an amount of 10%,with total gas flow at a rate of 500 mL/min and CO at a volume fraction of 30%.And then,the obtained calcine,after being ground to a fineness of-0.045 mm 65%,was subjected to a magnetic separation with magnetic intensity of 68.8 kA/m,yielding an iron concentrate with 60.65%TFe grade at 94.01%recovery.The subsequent thermodynamic analysis showed that at the temperature within the tested range,both dolomite and phosphogypsum were conducive to the decomposition of iron olivine rather than iron spinel,while sodium sulfate could work for both.