Abstract:
Extractive recovery of molybdenum (VI) from hydrochloric acid solutions in the presence of KCl as salting out agent using alkanols (pentanol and decanol) has been investigated by solvent extraction, propelled by the need to proffering alternatives to the scarce and relatively costly organophosphorous extractants. The effect of various parameters such as contact time, concentration of hydrochloric acid, pentanol and decanol concentrations, number of extraction stages, temperature, recycling of extractants, mixing of extractants and addition of foreign ions on molybdenum (VI) extraction were determined. The absorption and infrared spectra of the pure extractants and organic phases of molybdenum (VI) extracted from 2M and 7M HCl solution with pentanol and decanol respectively were also measured. It was observed that contact time of 5 and 10 min was sufficient for quantitative extraction of molybdenum (VI) with pentanols and decanol respectively. Increasing concentration of HCl at the studied range (0.0001-7M) yielded optimum percentage extraction (E %) of 50.5 with pentanol at HCl concentration of 2M, and 70.3% with decanol at HCl concentration of 7M. Both extractants produced a trend of increase in E % for Mo (VI) with increase in extractant concentration. The optimum extraction temperature for both extractants was 321K. On the number of required extraction stages, decanol gave a higher extraction efficiency after five consecutive extractions (E% = 98.1) than pentanol (E% = 90.6). In the recycling of extractants, the percentage extraction of Mo (VI) was at peak at first stage with both extractant. All extractants mixed with pentanol were found antagonistic with the exception of butan -1-ol and D2HEPA, with decanol only TBP and MIBK showed synergistic effect. All added foreign ions decreased E% for Mo (VI). The found optimum conditions were applied to the extraction of Mo (VI) from TREVO, a food supplement. From analytical and spectra data, the extracted complex have been formulated as MoO2Cl2.nROH
