SOLVENT EXTRACTION OF BISMUTH (III) FROM NITRIC ACID SOLUTIONS WITH HEXANOL AND METHYL ISOBUTYL KETONE (MIBK) IN N-HEPTANE

Abstract

The solvent extraction of Bismuth (III) from nitric acid solutions with Hexanol and Methyl Isobutyl Ketone (MIBK) in n-heptane as extractants has been investigated. The effect of various parameters such as extractants concentration, temperature, number of extraction stages, recycling, mixing of extractants and foreign ions on Bi (III) extraction were studied. The observed optimum conditions were applied to the extraction of Bi (III) from its Ore and Pepto- Bismol, a pharmaceutical drug for stomach disorder. From the equilibrium studies carried out at a contact time of 5 minutes, effect of varying extractants concentration 30 - 100 % (v/v) on Bi (III) extraction from 2 M HN03 solution, showed that the optimum extractant concentration for Bi (III) extraction from 2 M HN03 solution with Hexanol in n-heptane was 30 % v/v and MIBK in n-heptane was 50 % v/v. The optimum extraction temperature with Hexanol and MIBK in n-heptane was at 28 ℃. With the recycling of Hexanol and MIBK in n-heptane, at five stages employed in this study, the percentage Bi (III) extraction varied from 20 - 50 % for Hexanol in n-heptane and MIBK in nheptane varied from 44.2 - 50 %. For the number of batch extraction stages required for the extraction of Bi (III), the highest was at the fourth stage of extraction (E %= 67.4) with Hexanol in n-heptane while for MIBK (E % = 67.4). The addition of Zinc as a foreign ion resulted into least extraction for Bi (III) for both extractants. Bismuth - Xylenol Orange Spectrophotometry Method was used to determine bismuth in all samples. The Use of MIBK was found to be more efficient for the extraction of Bi (III) from acid leached real samples (Bismuth ore and Pepto- Bismol drug). Electronic and Infrared Spectra have also been used to clarify the nature of the organic phase extracts.