An Efficient Approach for Lithium and Aluminum Recovery from Coal Fly Ash by Pre-Desilication and Intensified Acid Leaching Processes
An Efficient Approach for Lithium and Aluminum Recovery from Coal Fly Ash by Pre-Desilication and Intensified Acid Leaching Processes
复制标题
通过预脱硅和强化酸浸工艺从粉煤灰中回收锂和铝的有效方法
DOI：
10.3390/met7070272
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发表时间：
2017-07-01
期刊：
影响因子：
2.9
通讯作者：
Li, Yanheng
中科院分区：
文献类型：
--
作者：
Li, Shenyong;Qin, Shenjun;Li, Yanheng
采用预脱硅和强化酸浸相结合的新工艺，从燃煤飞灰中回收锂铝。结果表明，高铝飞灰的主要成分为Al_2O_3和SiO_2，脱硅后Al/Si比由1.0提高到1.5。飞灰中的锂含量达到了国家回收标准。在酸浸条件下，锂的浸出率为82.23%，铝的浸出率为76.72%，最佳酸浸条件为：固液比1：20，温度120℃，浸出时间4h。部分莫来石相被溶解，大部分玻璃相浸出到溶液中。硅酸盐的生成阻碍了锂的运移，降低了锂的浸出率。这项工作表明，预处理是有效回收高铝和飞灰伴生锂的一种有前途的选择。
A novel technique was developed for the recovery of lithium and aluminum from coal fly ash using a combination of pre-desilication and an intensified acid leaching process. The main components of the high-aluminum fly ash were found to be Al2O3 and SiO2, and the Al/Si ratio increased from 1.0 to 1.5 after desiliconization. The lithium content of the coal fly ash met national recycling standards. The optimal acid leaching conditions, under which the leaching efficiencies of lithium and aluminum were 82.23% and 76.72%, respectively, were as follows: 6 mol/L HCl, 1:20 solid to liquid ratio, 120 degrees C and 4 h. During the hydrochloric acid pressure leaching process, spherical particles of desilicated fly ash were decomposed into flakes. Part of the mullite phase was dissolved, and most of the glass phase leached into the liquor. The generation of the silicates hindered lithium transport, which decreased the leaching rate of lithium. This work suggests that the preprocessing is a promising option for effective recovery of high-aluminum and fly ash-associated lithium.