Citric acid was used to selectively extract cobalt from limonite-type laterite ores in the presence of ammonium bifluoride.The results show that ammonium bifluoride enhances the leaching of cobalt by citric acid,and 8...Citric acid was used to selectively extract cobalt from limonite-type laterite ores in the presence of ammonium bifluoride.The results show that ammonium bifluoride enhances the leaching of cobalt by citric acid,and 84.5% cobalt is extracted from a laterite ore containing 0.13% Co when leached at ambient temperature for 2 h with 30 g/L citric acid and 10 g/L ammonium bifluoride.Pyrolusite is reduced by citric acid during leaching,cobalt intergrown with which is liberated and subsequently chelated by the citric acid.The extraction of cobalt is enhanced in the presence of ammonium bifluoride because the matrix of silicate minerals is destroyed by ammonium bifluoride and the adsorbed cobalt is subsequently liberated.展开更多
铝土矿中常伴有锂、镓、锆、稀土等有用组分,完全提取并准确测定其含量对于铝土矿资源综合评价和综合利用具有重要意义。然而铝土矿中常常含有少量刚玉,常规的四酸、五酸和封闭压力酸溶法对其分解不完全,导致测定结果偏低。本文采用氟...铝土矿中常伴有锂、镓、锆、稀土等有用组分,完全提取并准确测定其含量对于铝土矿资源综合评价和综合利用具有重要意义。然而铝土矿中常常含有少量刚玉,常规的四酸、五酸和封闭压力酸溶法对其分解不完全,导致测定结果偏低。本文采用氟化氢铵作熔剂,高温下在旋盖PFA小瓶中分解样品,通过在熔样过程中使用少量硫酸,对不同熔矿温度、消解时间及试剂用量等因素详细考察,确定了最佳熔矿条件[200℃,3h,试样比4∶1(称样量50mg)],建立了氟化氢铵分解-电感耦合等离子体质谱法测定含刚玉铝土矿中37种痕量元素的分析方法。本方法能快速、有效地分解含刚玉铝土矿,经三种铝土矿国家标准物质GBW07177、GBW07181和GBW07182验证,并与四酸、五酸和封闭压力酸溶法的测定结果对比,三种标准物质中Li、Ga、Sr、Zr、Pb等9种元素的回收率分别在95.0%~115.0%、90.0%~110.0%和90.0%~110.0%之间,测定值与认定值相符。同时,本方法实现了铝土矿(Al 2 O 3含量在42.97%~90.36%之间)中Al、Ti、P等主量元素的精确分析,进一步验证了其用来测定铝土矿中痕量元素的准确性。方法检出限为0.002~0.43μg/g,与传统硝酸-氢氟酸密闭消解法的检出限(0.000~0.48μg/g)基本相当,精密度在1.14%~8.84%之间,能够满足铝土矿中痕量元素的分析要求。展开更多
基金Project(50725416) supported by the National Natural Science Foundation of China for Distinguished Young Scholars
文摘Citric acid was used to selectively extract cobalt from limonite-type laterite ores in the presence of ammonium bifluoride.The results show that ammonium bifluoride enhances the leaching of cobalt by citric acid,and 84.5% cobalt is extracted from a laterite ore containing 0.13% Co when leached at ambient temperature for 2 h with 30 g/L citric acid and 10 g/L ammonium bifluoride.Pyrolusite is reduced by citric acid during leaching,cobalt intergrown with which is liberated and subsequently chelated by the citric acid.The extraction of cobalt is enhanced in the presence of ammonium bifluoride because the matrix of silicate minerals is destroyed by ammonium bifluoride and the adsorbed cobalt is subsequently liberated.
文摘铝土矿中常伴有锂、镓、锆、稀土等有用组分,完全提取并准确测定其含量对于铝土矿资源综合评价和综合利用具有重要意义。然而铝土矿中常常含有少量刚玉,常规的四酸、五酸和封闭压力酸溶法对其分解不完全,导致测定结果偏低。本文采用氟化氢铵作熔剂,高温下在旋盖PFA小瓶中分解样品,通过在熔样过程中使用少量硫酸,对不同熔矿温度、消解时间及试剂用量等因素详细考察,确定了最佳熔矿条件[200℃,3h,试样比4∶1(称样量50mg)],建立了氟化氢铵分解-电感耦合等离子体质谱法测定含刚玉铝土矿中37种痕量元素的分析方法。本方法能快速、有效地分解含刚玉铝土矿,经三种铝土矿国家标准物质GBW07177、GBW07181和GBW07182验证,并与四酸、五酸和封闭压力酸溶法的测定结果对比,三种标准物质中Li、Ga、Sr、Zr、Pb等9种元素的回收率分别在95.0%~115.0%、90.0%~110.0%和90.0%~110.0%之间,测定值与认定值相符。同时,本方法实现了铝土矿(Al 2 O 3含量在42.97%~90.36%之间)中Al、Ti、P等主量元素的精确分析,进一步验证了其用来测定铝土矿中痕量元素的准确性。方法检出限为0.002~0.43μg/g,与传统硝酸-氢氟酸密闭消解法的检出限(0.000~0.48μg/g)基本相当,精密度在1.14%~8.84%之间,能够满足铝土矿中痕量元素的分析要求。
