Solvent Extraction from Molten Salts. II. Mixed Mercury (II) Halides

The overall distribution ratio D for mercury (II) species between a polyphenyl eutectic mixture and molten LiNO 3 ‐KNO 3 eutectic at 150° was determined for HgCl 2 ‐ HgBr 2 , HgCl 2 ‐ HgBr 2 and HgBr 2 ‐ HgI 2 mixtures of varying composition. In the latter two cases, the plot of D vs R (= the ratio I total : Cl total or I total : Br total ) showed a maximum. A method was derived for direct calculation of K s , the equilibrium constant for the reaction HgA 2 + HgB 2 ⇋ 2HgAB in the salt phase, and K AB , the distribution coefficient of HgAB, from the values of D and R at the maximum. The obtained values of K s and K AB respectively are: for HgClBr 70 ± 30 and 3.9 ± 0.2, for HgClI 0.5 ± 0.3 and 90 ± 30. for HgBrI 0.10 ± 0.06 and 370 ± 200.