碱法从粉煤灰中提取铝硅的新探索

Technology Explore of Extracting Alumina and Silicon from Coal Ash with Alkali Method

碱石灰烧结法从粉煤灰中提取氧化铝的最佳工艺条件是:生料配比[N/R]为0.95,[C/S]为2.0,烧结温度1250℃,烧结时间30min;熟料溶出温度80℃,时间30min,调整液αK为1.60±0.05,氧化铝浓度10g/L,碳酸钠浓度12g/L;采用三段脱硅,精液硅量指数>600,精液分解温度90℃,种子加量20g/L。证明用粉煤灰碱-石灰烧结法生产氧化铝技术上可行,同时,提出了碱石灰烧结法生产粗氢铝后再重溶及低浓度处理粉煤灰联合生产水玻璃的工业应用改进途径。

The best process conditions of extracting alumina from coal ash with alkali lime sintering are as follows：the [N/R]in ingredients prescriptions is 0.95,the [C/S] is 2.0;Optimum sintering temperature is 1 250 ℃ and the time holds 30 min;Sintered block was dissolved in the solution which 1.60±0.05 molecule ratio αK,the concentration of Al2O3 is 10 g/L and the concentration of Na2CO3 is 12 g/L at 80 ℃ holding 30 min;By three-stage desiliconization,the silicon index in final pregnant liquor is larger than 600;The pregnant liquor decomposition temperature is about 90 ℃;The quantity of seed is not less than 20 g/L.The test results proved that the technology producing alumina with coal ash by alkali-lime sintering is doable.At the same time,for industry application,it also proposed several innovated ways such as crude hydrogen aluminum production by alkali lime sintering and then re-dissolved;dissolve fly ash with low sodium hydroxide concentration to produce water glass.