摘要
利用草酸预浸出低品位铝土矿,降低铁含量对酸法氧化铝生产工艺的影响,可提高低品位铝土矿的价值。同时,草酸浸出液通过光催化照射后分离出草酸溶液和草酸亚铁副产物,实现了草酸溶液循环利用。实验结果表明,75℃下,在1mol/L的草酸溶液中浸出2h,氧化铁的浸出率可达到96%,浸出后铝土矿中氧化铁含量由10.6%降低至0.5%以下。在光照催化300min内,浸出液中90%以上的草酸铁转变成草酸亚铁,实现浸出液中剩余草酸的循环再利用。从产品测试结果上看,光催化所得产品为β-FeC2O4·2H2O,是长度约为5μm的棒状结晶;浸出后的铝土矿采用酸法制备所得产品中氧化铁含量低于0.02%,达到国家标准的要求。
Iron oxide in low grade bauxite has badly effect for alumina production with acid technology. Oxalic acid solution as an extractant was employed in the extracting process to remove iron oxide. The resultant Fe（ Ⅲ ） oxalate solution was irradiated by sun light to precipitate the crystalline of Fe（ Ⅱ ） oxalate and the filtrate could be reused in the next cycle. The test results show that the content of ferric oxide in low grade bauxite was reduced from 10. 6% to less than 0. 5% when treated by using 1 mol/L oxalic acid solution at 75 ℃ for 2 hours. Under the sunlight irradiation, more than 90% of Fe（Ⅲ） oxalate in the extracted solution was transformed into the precipitation of Fe（ Ⅱ ） oxalate crystallite in 300 min. The byproduct was identified as β-FeC204 . 2H20 with 5 μm rod-like crystal by XRD and SEM. The aluminum hydroxide product for the treated low grade bauxite with acid method has a content of ferric oxide as low as 0. 02%, which is lower than the point of national standard.
基金
国家自然科学基金面上项目(51171029)
关键词
酸法氧化铝
氧化铁
草酸
光催化
alumina production with acid technology, ferric oxide, oxalic acid, sunlight irradiation
