利用粉煤灰制备高纯氧化铝新技术

New Technology of Preparing High Purity Alumina with Coal Fly as Raw

粉煤灰是火力发电厂排放的固体废弃物,实现高铝粉煤灰的高附加值利用是行业的研究热点。研究了硫酸氢铵溶液浸出粉煤灰制备高纯氧化铝的工艺技术,结合SEM、XRD等手段对获得的产物进行了表征。结果表明,通过调整相应的工艺参数可获得片状、条状等形貌的氧化铝前躯体产物。前躯体在500℃条件下煅烧4 h可获得比表面积为571.32 m^2/g、孔体积为0.75 cm^3/g、孔径尺寸为6.15 nm的介孔氧化铝。随着煅烧温度的升高,氧化铝颗粒趋于球形转变。经1200℃煅烧形成的氧化铝粒径大约为60 nm,纯度≥99.92%。获得的氧化铝产品可用做催化剂载体材料、复合材料、精细陶瓷等领域。

Coal fly ash is the major coal solid waste in thermal power plants. Extracting of aluminum from coal fly ash is environmentally and scientifically significant for disposing and utilizing waste materials and exploring new aluminum source, and has attracted extensive attention recently. A new technology of preparing high purity alumina by leaching fly ash with ammonium hydrogen sulfate aqueous is introduced. The characterization of following products was carried by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR）, N2 adsorption-desorption method Field emission scanning electron microscopy （SEM） and. The results show that the alumina precursor with discs or strip morphology can be obtained by controlling the corresponding technological parameters. The mesoporou γ-Al2O3 obtained by calcining AACH at 500 °C for 4 h exhibits high specific surface area of 571.32 m^2/g, a pore volume of 0.75 cm^3/g and pore size of 6.15 nm. Alumina particles transform to the spherical shape with increasing calcining temperature. The alumina with particle size in diameter about 60 nm and purity not less 99.92% is obtained by calcining AACH at 1200°C for 2h. The so called alumina product may be used as catalyst carrier material, composite material, fine ceramics and other aspects.