为实现固体废弃物循环流化床粉煤灰的综合利用,探寻铝土矿的替代资源,采用微波消解、亚熔盐法及直接酸溶法对循环流化床粉煤灰中含量高的金属元素铝、铁和钛进行了溶出实验,比较了不同条件对粉煤灰中上述元素溶出率的影响.结果表明:微波消解粉煤灰,消解剂为质量分数20%的NaOH溶液或HNO3-HCl-HF混合酸,粉煤灰中的铝都全部溶出,但是钛和铁在碱性条件下消解,溶出率小于50%;用亚熔盐法和酸法溶出粉煤灰,粉煤灰中的铝、铁和钛的溶出率都小于50%,但亚熔盐溶出后再加酸浸出,铝和铁都全部溶出.本研究为循环流化床粉煤灰的综合利用提供理论参考.
In order to achieve the comprehensive utilization of fly ash solid waste in recirculating fluidized bed and explore the alternative resources of bauxite, the dissolution of metal elements including aluminum, iron and titanium in circulating fluidized bed fly ash was studied by microwave digestion, sub-molten salt method and direct acid dissolution. Effects of different digestion conditions on the dissolution rate of various elements in fly ash were investigate and compared. The results showed that fly ash sample was digested by microwave method and the dissolution rate of aluminum element in fly ash was higher than 90% using 20% NaOH solution or HNO3-HCl-HF mixed acid as digestion solvent. The dissolution rates of titanium and iron were both less than 50% under alkaline conditions. Fly ash is difficult to dissolve by the sub molten salt method and acid method. But aluminum and iron were dissolved by acid leaching using the sub molten salt method. It provides a theoretical reference for the comprehensive utilization of circulating fluidized bed fly ash.
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