高磷鲕状赤铁矿气基还原脱磷及磷赋存形态

Gas-based reduction dephosphorization and phosphorus occurrence form of high-phosphorus oolitic hematite

中国高磷鲕状赤铁矿的储量十分丰富,但由于其矿物组成复杂、磷含量高等特点而不能直接作为炼铁原料,这使得其利用价值受到了严重限制。因此,以高磷鲕状赤铁矿为研究对象,采用气基还原-磁选工艺研究了还原温度、保温时间、碱度以及H_(2)流量4个工艺参数对脱磷效果的影响。通过XRD、SEM等检测手段对还原产物的微观结构及组成进行分析。研究结果表明:随着还原温度、保温时间、碱度以及H_(2)流量的升高,铁品位以及铁回收率逐渐升高,而磷含量则与之相反。通过对比不同条件下各还原产物的显微结构可以发现,还原温度、保温时间以及碱度均能促进铁颗粒聚集长大并与脉石矿物分离,而H_(2)流量对这一现象的改变并不明显。在还原温度1050℃、保温时间90min、碱度1.2、H_(2)流量200mL/min的条件下,各项指标最佳,此时精矿铁品位为77.53%、铁回收率为77.94%,磷的质量分数为0.26%,脱磷率达到71.74%。

The reserves of high-phosphorus oolitic hematite in China are abundant.But due to its complex mineral composition and high phosphorus content,it cannot be directly used as a raw material for ironmaking,which seriously limits its utilization value.Therefore,taking high phosphorus oolitic hematite as the research object,the influence of four process parameters,including reduction temperature,holding time,alkalinity,and hydrogen flow rate,on the dephosphorization effect was studied using a gas based reduction magnetic separation process.The research results indicate that as the reduction temperature,holding time,alkalinity,and hydrogen flow rate increase,the iron grade and iron recovery rate gradually increase,while the phosphorus content decreases.By comparing the microstructure of each reduction product under different conditions,it was observed that the reduction temperature,holding time,and alkalinity can all promote the aggregation and growth of iron particles and their separation from gangue minerals,while the change in hydrogen flow rate is not significant.Under the conditions of reducing temperature of 1050℃,holding time of 90 min,alkalinity of 1.2,and hydrogen flow rate of 200 mL/min,all indicators are optimal.At this time,the iron grade of the concentrate is 77.53%,the iron recovery rate is 77.94%,the mass fraction of phosphorus is 0.26%,and the dephosphorization rate reaches 71.74%.