The extraction of nitrates by tri-n-butyl phosphate (TBP). Part 3.—Extraction at trace concentrations

An equilibrium study of the chloride and nitrate systems of praseodymium and neodymium with tributyl phosphate and acid

“…It is generally assumed (19,26,27) that the rare-earth containing species present in an aqueous rare-earth solution are M , MA , MA , ,+3 ".+2 _ +1 2 and MA^, where M refers to the rare earth and A is a ligand such as chloride or nitrate. There is also the possibility of various forms of rare-earth hydroxides (25,32) however, these are present only in solutions whose pH is above its equivalence point, and will not be considered to be present in this work.…”

Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

“…The coordination number can be inferred from experiments in which the organic-phase extractant concentration is varied. Extensive use of this method was first reported by Hesford and McKay (1958) and is developed as follows: Define a distribution ratio as the ratio of salt concentration in the organic phase to the concentration in the aqueous phase, Combine this definition with Eq. (2-55) and rearrange to obtain which may be expressed in logarithmic form as (2-56) (2-57)…”

“…Experiments performed at various organic-phase CMPO concentrations and fixed aqueous-phase compositions are used to infer the stoichiometry of extraction by the slope-analysis method described by Hesford and McKay (1958). Under conditions where both phases are nearly ideal, a plot of the logarithm of the distribution ratio vs the logarithm of the extractant concentration gives a straight line whose slope is equal to the extraction stoichiometry (sometimes called solvation number).…”

Solvent Extraction of Iron(III) with Tri Methyl Amine from Mineral Acid Solutions

“…The extraction isotherm method 9 and distribution ratio method 10 were employed to determine the composition of the extracted species. In the extraction isotherm method the limiting ratio of the metal to TMA was found unity with all the acid systems ( Figure 2).…”