Abstract
A method for the back-extraction of metal complexes in methylisobutyl ketone (MIBK) by its dilution with hexane is proposed on the basis of drastic decrease in the metal extraction into this solvent as a result of dilution with a nonpolar solvent.
Extraction and back-extraction of mercury (II) iodide and thallium (III) chloride complexes were demonstrated as examples. The metal ion was first extracted from the sodium halide solution into MIBK. Then a portion of this MIBK was diluted with a certain volume of hexane and was agitated with a solution of the same sodium halide. The distribution ratio of this back-extraction was calculated. The extraction was impaired very much by the dilution; dilution of one volume of MIBK with three volumes of hexane enabled back-extraction of more than 90% of the metal ion into one volume of the halide solution from which more than 99% of the metal ion was extracted into undiluted MIBK.
The statistical treatment of this back-extraction is given and the possibility of the use of this method for various metal ions is considered.
