Separation of niobium and tantalum from Mozambican tantalite by ammonium bifluoride digestion and octanol solvent extraction
Separation of niobium and tantalum from Mozambican tantalite by ammonium bifluoride digestion and octanol solvent extraction
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DOI：
10.1016/j.hydromet.2012.06.008
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发表时间：
2012-11-01
期刊：
影响因子：
4.7
通讯作者：
Crouse, P. L.
中科院分区：
文献类型：
--
作者：
Kabangu, M. J.;Crouse, P. L.
采用熔融氟化氢铵（NH 4 HF 2）代替氢氟酸对莫桑比克钽铁矿进行了溶出试验。用正辛醇和仲辛醇作萃取剂，从水浸出滤液中萃取铌和钽。主要的工艺变量是时间、温度和二氟化物与矿石的质量比，对于二氟化物处理步骤，沿着含水滤液的硫酸浓度和溶剂萃取接触时间。得到的最佳参数为氟化氢处理的反应时间为3 h，反应温度为250 ℃，钽酸盐与氟化氢的质量比为1：30。在此条件下，铌和钽的回收率分别达到97.24%和98.66%。将硫酸（H2SO 4）引入水相中增加了用辛醇萃取Nb和Ta。结果表明，5 M至6 M的硫酸浓度导致钽的良好萃取。为了有效地提取铌，必须使用高于5 M的酸浓度。进料溶液和溶剂之间需要10分钟的接触时间。从实验数据构建的McCabe-Thiele平衡图表明，在最佳萃取条件下，两个和三个萃取阶段分别足以几乎完全萃取Ta和Nb。(C)2012爱思唯尔有限公司版权所有。
Tantalite ore from Mozambique was digested using molten ammonium bifluoride (NH4HF2) as an alternative to hydrofluoric acid. Niobium and tantalum were extracted from the water-leached filtrate using 1- and 2-octanol as extractants. The main process variables are time, temperature and the bifluoride-to-ore mass ratio, for the bifluoride treatment step, along with the sulphuric acid concentration of the aqueous filtrate, and the solvent-extraction contact time. The optimum parameters obtained for the bifluoride treatment were a reaction time of 3 h, a reaction temperature of 250 degrees C, and a tantalite-to-bifluoride mass ratio of 1:30. Under these conditions, up to 97.24% of Nb and 98.66% of Ta were recovered. Introduction of sulphuric acid (H2SO4) into the aqueous phase increases the extraction of Nb and Ta with octanol. It is shown that a 5 M to 6 M sulphuric acid concentration results in good extraction of tantalum. An acid concentration higher than 5 M must be used for efficient extraction of niobium. A contact time of 10 min between the feed solution and the solvent is required. McCabe-Thiele equilibrium diagrams constructed from the experimental data suggest that two and three extraction stages are sufficient for almost complete extraction of Ta and Nb respectively, at optimum extraction conditions. (C) 2012 Elsevier B.V. All rights reserved.