采用焙烧-酸浸取从粉煤灰中提取Al2O3.以硫酸铵为活化剂,在400℃下焙烧,使粉煤灰中的惰性Al2O3转变为活性硫酸铝铵(NH4Al(SO4)2),硫酸为溶出剂.探讨了焙烧温度、硫酸铵与粉煤灰混料比、酸浸反应时间、酸浸温度、硫酸质量分数及液固比等因素对粉煤友中Al2O3提取率的影响.结果表明,当焙烧温度为400～450℃,(NH-4)2SO4与Al2O3摩尔比为8时,粉煤灰中莫来石相完全消失；当(NH4)2SO4与Al2O3摩尔比为6,焙烧时间为120 min,硫酸质量分数为20％,浸取温度为80℃,溶出时间为2h,液固比为8mL/g时,粉煤灰中Al2O3提取率可达到78.86％.%A new calcining-leaching process was introduced to extract alumina (Al2O3) from coal fly ash (CFA).The CFA was mixed with ammonium sulfate ((NH4)2SO4) and calcined at 400 ℃ to yield aluminum ammonium sulfate (NH4Al(SO4)2),subsequently take sulfuric acid as leaching agent.The influence of technical conditions on leaching of Al2O3 was examined,including calcining temperature,the mass of ammonium sulfate,acid leaching time,leaching temperature,sulfuric acid mass fraction,as well as liquid to solid ratio and other factors respectively.The results show that as the calcining temperature is 400～450 ℃,molar ratio of (NH4)2SO4 and Al2O3 is 8,the mullite phase disappears.The Al2O3 extraction efficiency is high on following technological conditions,the calcining time is 2 h; in sulfuric acid dissolution stage to determine the H2SO4 mass fraction of 20％,the leaching temperature of 80 ℃ and dissolution duration of 2 h,the ratio of solution and solidreaction material is 8 mL/g.Under these conditions,the Al2O3 extraction efficiency of CFA is 78.86％.
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