拜耳法还原溶出过程中赤铁矿的转化与铁的回收（英文）

Transformation of hematite in diasporic bauxite during reductive Bayer digestion and recovery of iron

提出在拜耳法还原溶出过程中,添加铁粉作为还原剂实现铁矿物的定向转化;根据各矿物间表面性质差异完成铁矿物与钠硅渣(脱硅产物,DSP)的矿相解离。研究结果表明:磁铁矿与钠硅渣在zeta电位、润湿性和溶剂化趋势上的差异使其相对于赤铁矿更易于聚集长大和实现单体解离;采用还原拜耳法溶出处理高铁一水硬铝石型铝土矿时,提高还原剂添加量和溶液苛性碱浓度均有利于铁矿物的转化,同时氧化铝相对溶出率可达98.91%;通过磁选分离还原溶出赤泥中的铁,可以获得铁精矿品位TFe≈60%、矿石中铁回收率大于86%、外排赤泥减少70%的良好指标。研究结果有助于高效处理高铁一水硬铝石型铝土矿新技术的开发,也可为高铁赤泥的综合利用研究提供借鉴。

The reductive Bayer digestion by using iron powder as reductant is proposed to convert hematite to magnetite and further to dissociate iron minerals from sodium aluminosilicate hydrate(desilication product,DSP)based on the differences of their surface properties.The results show that the differences of surface properties between magnetite and DSP in zeta potential,wettability and solvation trend facilitate magnetite to agglomerate,grow up and thus to dissociate from DSP.The increments of reductant amount and alkali concentration favor the transformation of hematite in digestion with the relative alumina recovery of98.91%.Processing the resultant red mud can obtain qualified iron concentrate with iron grade of approximate60%and recovery of about86%through magnetic separation,resulting in reduction of red mud emission higher than70%.The results are potential to develop a novel technology for processing high iron diasporic bauxite efficiently and provide references for comprehensive utilization of high iron red mud.