煤微波法脱硫过程中铁-硫化合物的变化

在不加浸提剂和通以氮气(含氧约1%)条件下,用2.45GHz微波照射约100s,东林煤(D)和鱼田堡煤(Y)的脱硫率均可达到20%以上。照射后进一步用5%的过量稀盐酸处理,脱硫率可高达68%。穆谱分析麦明,D、Y均含黄铁矿和硫酸亚铁,D还存在少量黄钾铁矾。经微波照射,黄铁矿转变成磁黄铁矿和陨硫铁,硫酸亚铁可能转变成其它铁相,其程度随着脱硫深度的变化面变化。用稀酸处理几乎可以除尽煤中磁铁矿和陨硫铁。因而微波照射与酸洗结合将是一种有效的脱硫方法。

Changes of Iron-Sulfur Compounds in the Process of Coal Microwave Desulfurization

The total sulfur in Donglin (D) and Yutianbao (Y) coals can be removed above 20% by irradiation with 2.45 GHz microwave for a duration of about 100 s without leachant in nitrogen atmosphere (containing approximately 1% oxygen). The percentage sulfur removal may be increased to 68% after the irradiated coals were further treated with 5% hydrochloric acid. It was shown by Mssbauer spectroscopy that pyrite and ferrous sulfate were both present in the coals, and a little jarosite existed in Donglin coal. Microwave exposure converted pyrite to pyrrhotite and/or troilite, and ferrous sulfate to other phases. The extent of conversion was changed with varying desulfurization level, and pyrrhotite and troilite can be removed rather completely from the coals by treatment with dilute hydrochloric acid. Therefore, microwave irradiation combined with acid washing will be an effective method of disulfurization.