褐煤基中孔磁性活性炭的制备

以宝日希勒褐煤为原料、Fe3O4为磁性添加剂,采用水蒸气活化法制备磁性活性炭.考察Fe3O4添加量、活化温度、活化时间和水蒸气通量对活性炭孔结构发育的影响,采用振动样品磁强计（VSM）对活性炭的磁性能进行表征.结果表明：随着Fe3O4添加量的升高,活性炭的磁性能逐渐增强,当Fe3O4的添加量达到6 g/100 g煤时,活性炭的比磁化率达到20.162×10^-7 m^3/kg,满足强磁场磁选回收的要求;Fe3O4添加降低了活性炭的烧失率,从而影响孔结构发育;活性炭的亚甲蓝值和碘值随着活化温度的升高而增大,至烧失率为71.92％时,活性炭的孔结构仍处于发育阶段;而活化时间和水蒸气通量增大使得碘值和亚甲蓝值先增大后减小,并在烧失率50％ ～60％处出现峰值;添加Fe3O4能促进磁性活性炭的中孔发育,在烧失率相近的情况下,100 g煤中添加6g Fe3O4可以得到比表面积、中孔孔容和中孔率分别为509.14 m^2/g、0.241 cm^3/g和58.1％的磁性活性炭样品.

Preparation of mesoporous magnetic activated carbon from lignite

This paper is concerned specifically with the preparation of magnetic activated carbons （MACs） from Baorixile lignite in the presence of Fe3O4,using steam activation method; the investigation into the effects of Fe3O4 content,activation temperature,activation time and steam flow rate on the porosity of activated carbon ; and the characterization of the magnetic properties of the MACs by vibrating sample magnetometer（VSM）.The results show that an increase in Fe3O4 content means a gradually increasing strength in magnetic activated carbon,as when activated carbon magnetic susceptibility of 20.162 × 10^-7 m^3/kg,due to the Fe3O4 addition of up to 6 g/100 g（coal） is adequate for the magnetic separation in high-intensity magnetic field ; the addition of Fe3 O4 in the raw materials triggers a reduction in burn-off of MAC,with a consequent negative effect on the development of pore structure ; MACs likely have an increased methylene blue values and iodine values,due to the higher activation and retain the pore structure in development stage even in the case of the burn-off of over 71.92%; an increase in activation time and steam flow rate gives these values an initial increase and a subsequent decrease and produces a peak in the case of the burn-off of 50% ～ 60% ; and the addition of Fe3O4 promotes the pore development of magnetic activated carbons and the addition of Fe3O4 content into 6 g/100 g（coal） in the presence of approximate burn-off yields magnetic activated carbon samples with specific surface area,mesopore volume,and mesopore ratio of 509.14 m^2/g,0.241 cm^3/g and 58.1%,respectively.