摘要
Red-mud is the residue from the Bayer process, in which the iron minerals should be removed before red-mud is used to produce refractory materials. The iron minerals in red-mud were extracted by oxalic acid solution. The content of Fe （calculated in Fe203） in red-mud was reduced from 17.6% to less than 1% after being treated by 1 mol/L oxalic acid solution at 75 ℃ for 2 h. The Fe（Ⅲ） oxalate solution obtained was then irradiated by UV light, resulting in the precipitation of Fe（Ⅱ） oxalate. Under UV photocatalysis, more than 90% of Fe（Ⅲ） oxalate in the extracted solution was transformed into the precipitation of Fe（Ⅱ） oxalate crystallite （fl-FeC2O4·2H2O）. The filtrate from the Fe（Ⅱ） oxalate precipitate filtration could be reused in the next cycle. The mechanism ofUV photocatalysis precipitation was also discussed.
利用草酸作为浸出剂以除去拜耳法残渣赤泥中的氧化铁,从而提高赤泥的工业应用价值,同时对草酸浸出液进行紫外光照射,将草酸铁还原成草酸亚铁沉淀,实现草酸溶液循环再利用。实验结果表明,在75°C下,赤泥在1mol/L草酸溶液中浸出2h,氧化铁的浸出率可达到96%,浸出后赤泥中氧化铁的含量由17.6%降低至小于1%。在紫外光照催化作用下,1h内浸出液中90%以上的草酸铁转变成草酸亚铁沉淀,剩余草酸可循环再利用。该草酸亚铁为β-FeC2O4.2H2O。对UV催化沉淀的机理进行讨论分析。
基金
Project (2010AA101703) supported by the National Hi-tech Research and Development Program of China
作者简介
Corresponding author:陈咏梅,Tel/Fax:+86-10-64435452,E-mail:chenym@mail.buct.edu.cn;Corresponding author:万平玉;pywan@mail.buct.edu.cn.
