SNG飞灰制备氧化铝技术经济分析

Technical and economic analysis on alumina production from SNG coal fly ash

粉煤灰制备氧化铝可使合成天然气(SNG)产生的灰渣得到综合利用,同时能够解决灰渣污染的问题。简述了酸法工艺和碱法工艺技术的优缺点,并对2种工艺的运行成本及收益做了计算。酸法工艺将粉煤灰直接与酸反应,其工艺简单,但是存在酸液腐蚀设备以及含硅废渣二次污染的缺点。碱法工艺在氧化铝溶出之前增加了焙烧活化工序,使提铝过程更为温和,但是活化过程中能耗较高,容易造成能源浪费。碱法工艺在提铝的同时最大限度地利用了二氧化硅,提升了产品的附加值,使碱法工艺的利润高于酸法。综合比较,碱法工艺具有更好的市场和应用前景。

The preparation of alumina with coal fly ash is good for the comprehensive utilization of slag produced during syn- thetic natural gas （SNG） processes and meanwhile it can also solve the problem of fly ash pollution.The advantages and dis- advantages of the acid process and alkali process were introduced, and the operation cost and profit of these two processes were calculated.The acid process,which involves the direct reaction of fly ash and acid, has the advantage of easy to opera- ting.However, it still exhibits the disadvantages of equipment corrosion and pollution by silica-contained slag.During the alkali process, fly ash was firstly calcined with lime, which makes the process of extracting aluminum become more moderate.How - ever, it will consume more energy during calcination.But anyhow the alkali process facilitates the usage of silica, and pro- motes the additional value of products.The alkali process has more profit than the acid process.Based on comprehensive com- parison, the alkali process exhibits better market and application prospects.