NOBLE METALS AND ALLOYS | |
Название | Some features of the silver extraction from nitrate and chloride solutions by bis(2,4,4-trimethylpentyl)dithiophosphinic acid disulfide |
DOI | 10.17580/tsm.2019.07.04 |
Автор | Grigorieva N. A., Fleitlikh I. Yu., Pavlenko N. I. |
Информация об авторе | Institute of Chemistry and Chemical Technology SB RAS, Federal Research Сenter “Krasnoyarsk Science Сenter” Siberian branch of Russian Academy of Sciences, Krasnoyarsk, Russia: N. A. Grigorieva, Senior Researcher, e-mail: natasha@icct.ru |
Реферат | The data on the extraction of silver from nitric (nitrate) and hydrochloric acid solutions by a new highly efficient extractant: bis (2,4,4-trimethylpentyl) dithiophosphinic acid disulfide in toluene are given in this work. The stability of L in solutions of HNO3 was studied using IR spectroscopy. It is shown that the extractant is stable up to 3.0 mol/dm3 of HNO3. At concentrations ≥3.0 mol/dm3, a change in the spectra was observed associated with the appearance of sulfoxides and sulfones, which indicates a partial degradation of the extractant. An increase of nitric acid concentration leads to a decrease in the silver extraction due to the formation of a newly extracted complex [L·(AgNO3·HNO3)n] (where n = 1–4) in the organic phase which, along with the partial decomposition of the extractant, leads to a deterioration of silver extraction. An increase of hydrochloric acid concentration leads to a decrease in the silver extraction due to the formation of non-extracting anionic silver complexes in the aqueous phase (AgCl2, AgCl3 и AgCl4). The stability of L for five cycles of extraction — stripping in the extraction of silver from hydrochloric acid solutions using thiourea solution (0.75 mol/dm3) mixed with sulfuric acid (0.5 mol/dm3 H2SO4) as the re-extractant was made. The high stability of the extractant was shown — the distribution coefficients of silver did not change from cycle to cycle. Recommendations are given on the composition of aqueous solutions for effective silver extraction by disulfide while maintaining a high stability of the extractant. |
Ключевые слова | Solvent extraction, silver, mineral acids, bis(2,4,4-trimethylpentyl)-dithiophosphinic acid disulfide, stability of the extractant, stripping |
Библиографический список | 1. Paiva A. P. Reviev of recent solvent extraction studies for recovery of silver from aqueous solutions. Solvent extraction and ion exchange. 2000. Vol. 18, No. 2. pp. 223–271. |
Language of full-text | русский |
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