磁化焙烧-磁选综合回收回转窑除尘灰中铁的试验研究

Recovery of Iron from Dust Collected from Rotary Kiln by Magnetizing Roasting-Magnetic Separation

采用焙烧-磁选方法对新疆克州建宝选矿厂回转窑窑尾除尘灰进行了回收铁的试验研究。考察了焙烧温度、焙烧时间、磨矿粒度、磁场强度等因素对选铁效果的影响,并比较了直接焙烧和造球焙烧效果的差异。结果表明,除尘灰经720℃/30 min、760℃/30 min或800℃/20 min焙烧,在磁场强度为0.18 T条件下进行分选,获得的铁精矿品位57%以上,精矿铁回收率90%左右,铁精矿中杂质含量S、P低,符合铁精矿要求。除尘灰直接焙烧或造球焙烧后磁选所得铁精矿品位和回收率差异不大,考虑动态回转窑处理该矿,在粉矿中添加一定量的膨润土较大地提高了造球强度,在不影响指标的情况下,可满足回转窑的生产要求。

Laboratory tests were conducted to recover iron from dust collected from exit of rotary kilns of Jianbao Concentrator in Kizilsu Kirghiz Autonomous Prefecture of Xinjiang Uyghur Autonomous Region, adopting magnetizing roastingmagnetic separation process. After an investigation of the influence of parameters, such as roasting temperature, roasting time, grinding fineness, magnetic field strength, on the iron-recovery efficiency, the effect of direct roasting and pelletization-roasting was compared. The results showed that, after the dust was roasted under conditions of 720 °C/30 min, 760 °C/30 min or 800 °C/20 min, and separated under a magnetic field strength of 0. 18 T, iron concentrate was obtained with the grade and recovery above 57% and around 90%, respectively, and with low content of sulfur and phosphorus impurities. The difference in iron grade and recovery of magnetic separation concentrate is not distinct for the dust obtained from direct roasting or pelletization-roasting. If being treated in a dynamic rotary kiln, powder ore by adding an amount of bentonite can greatly increase the strength of pellets, meeting the requirement of kiln operation without affecting the processing index.