Ammonium aluminum sulfate hydroxide[NH4Al（SO4）2·12H2O], the precursor of Al2O3, was prepared with the method of sintering, leaching and adjusting the pH value by using fly ash and ammonium sulfate as raw materi...Ammonium aluminum sulfate hydroxide[NH4Al（SO4）2·12H2O], the precursor of Al2O3, was prepared with the method of sintering, leaching and adjusting the pH value by using fly ash and ammonium sulfate as raw materials.High-purity alumina was prepared by calcining NH4Al（SO4）2·12H2O.The effects of the temperature and time of sintering, molar ratio of（NH4）2SO4 vs the Al2O3 in fly ash and the grain size of fly ash on the extraction efficiency of Al2O3 from fly ash were studied.The efficiency of Al2O3 extraction could reach 95.6 percent under the optimum conditions.The purity of the Al2O3 from calcining NH4Al（SO4）2·12H2O that was refined by recrystallization was higher than 99.9 percent.展开更多
By desilication treatment,the Al2O3/SiO2 molar ratio of coal fly ash could be improved to the range of 1.63-2.0.The desilicated coal fly ash(DSCFA)was enriched in alumina extraction.A processing technology was develop...By desilication treatment,the Al2O3/SiO2 molar ratio of coal fly ash could be improved to the range of 1.63-2.0.The desilicated coal fly ash(DSCFA)was enriched in alumina extraction.A processing technology was developed for alumina extraction from the DSCFA with the lime sintering process.Ca/(SiO2+TiO2)molar ratio,and NaO/Al2O3 molar ratio,sintering time,and temperature were the most significant parameters impacting on the aluminum extraction efficiency.The optima aluminum extraction efficiency was obtained under conditions of Ca/(SiO2+TiO2)molar ratio of 2.0,NaO/Al2O3 molar ratio of 0.98,and sintering at 1 200 ℃for 60 min.Astandard industrial dissolution method was used under conditions of caustic ratio(αk=n(NaO)/n(Al2O3)of 2.0,Al2O3 concentration of 50 g/L,sodium hydroxide concentration(Nk)of 60.78 g/L,Na2CO3 concentration of 10 g/L,temperature of 85℃, and dissolution duration of 10 min.The final aluminum extraction efficiency was 90%.展开更多
文摘Ammonium aluminum sulfate hydroxide[NH4Al（SO4）2·12H2O], the precursor of Al2O3, was prepared with the method of sintering, leaching and adjusting the pH value by using fly ash and ammonium sulfate as raw materials.High-purity alumina was prepared by calcining NH4Al（SO4）2·12H2O.The effects of the temperature and time of sintering, molar ratio of（NH4）2SO4 vs the Al2O3 in fly ash and the grain size of fly ash on the extraction efficiency of Al2O3 from fly ash were studied.The efficiency of Al2O3 extraction could reach 95.6 percent under the optimum conditions.The purity of the Al2O3 from calcining NH4Al（SO4）2·12H2O that was refined by recrystallization was higher than 99.9 percent.
基金Project(YFZX(0804))supported by Science Foundation of the Pingshuo Coal Industry Company,China
文摘By desilication treatment,the Al2O3/SiO2 molar ratio of coal fly ash could be improved to the range of 1.63-2.0.The desilicated coal fly ash(DSCFA)was enriched in alumina extraction.A processing technology was developed for alumina extraction from the DSCFA with the lime sintering process.Ca/(SiO2+TiO2)molar ratio,and NaO/Al2O3 molar ratio,sintering time,and temperature were the most significant parameters impacting on the aluminum extraction efficiency.The optima aluminum extraction efficiency was obtained under conditions of Ca/(SiO2+TiO2)molar ratio of 2.0,NaO/Al2O3 molar ratio of 0.98,and sintering at 1 200 ℃for 60 min.Astandard industrial dissolution method was used under conditions of caustic ratio(αk=n(NaO)/n(Al2O3)of 2.0,Al2O3 concentration of 50 g/L,sodium hydroxide concentration(Nk)of 60.78 g/L,Na2CO3 concentration of 10 g/L,temperature of 85℃, and dissolution duration of 10 min.The final aluminum extraction efficiency was 90%.
