粉煤灰的综合利用现状及存在问题浅析

这是一篇矿物加工工程领域的论文。本研究以贵州某电厂粉煤灰为研究对象，综合运用多种测试手段对粉煤灰进行矿物组成及元素含量测定。结果表明，粉煤灰中主要矿物为莫来石、石英和铁矿物（5.46%的磁铁矿以及4.77%的赤铁矿），主要化学成分为SiO₂、Al₂O₃和Fe₂O₃，含量分别达到36.88%、20.89%和14.58%。此外，原灰中锂的含量高达307 g/t，显示出一定的综合利用价值。粒度分析表明，粉煤灰75 μm以下累积产率高达83.4%，整体颗粒较细，且锂和铁主要富集在-75 μm的粒级中。采用还原焙烧的方法将粉煤灰中弱磁性的赤铁矿转化为强磁性的磁铁矿，再采用湿式磁选方法对粉煤灰进行除铁研究。结果表明：以粉煤灰中的残碳为还原剂，焙烧温度为700 ℃，焙烧时间为45 min，磁场强度为240 mT的条件下，采用“一次粗选-两次扫选”的磁选工艺，粉煤灰中铁去除率达到63.27%，同时锂的回收率达到80.31%，实现了铁杂质的选择性脱除。

Preparation of novelceramic tiles with high Al2O3 content derived from coal fly ash

This is an essay in the field of mineral processing engineering. In this study, coal fly ash from a power plant in Guizhou was used as the research object. A series of test methods were comprehensively applied to the determination of the mineral composition and element content of coal fly ash. The results show that the main minerals in coal fly ash are mullite, quartz and iron minerals (5.46% magnetite and 4.77% hematite) , and the main chemical components are SiO₂, Al₂O₃ and Fe₂O₃, with the contents of 36.88%, 20.89% and 14.58%, respectively. In addition, the content of lithium is as high as 307 g/t, which shows a certain comprehensive utilization value. Particle size analysis shows that the cumulative yield of coal fly ash below 75 μm is as high as 83.4%, which indicates that the overall particles are finer. Lithium and iron are mainly concentrated in the -75 μm fraction. Reduction roasting was used to convert the weakly magnetic hematite in coal fly ash into strong magnetic magnetite, and then the wet magnetic separation method was used to remove iron from the fly ash. The results show that with the residual carbon in coal fly ash as the reducing agent, the roasting temperature 700 ℃, the roasting time 45 min, and the magnetic field strength 240 mT, and followed by a magnetic separation process of