THE PARTITIONING AND IONIC COMPETITION OF METAL - CHELATES IN THE ELECTROLYTIC FOAM SEPARATION PROCESS

摘要

In this study, the electrolytic foam separation process was used to treat meal-chelate solutions at varying pH values and with varying surfactant chelating agent to metal (S/M) ratios. The ionic competition characteristics of the metalchelate systems and the partitioning of chelates during the electrolytic foam separation process were also investigated by the ~1HFT-NMR method. Results of the ~1HFT-NMR analysis showed that, in the Ni-citrate-NDDTC(sodium diethyl dithiocarbamate) system with an S/M ratio of 4, the Ni-NDDTC chelate formation efficiencies for pH values of 4,7, and 10 were 87/100, 100/100, and 93/100, respectively. These results were consistent with measurements of efficiency of Ni removal following 90 minutes of flotation including that the efficiency of Ni removal in the Ni-citrate-NDDTC system was highest at pH=7 (95/100), and was lower at pH=4 (38/100) and pH=10 (74/100). This investigation demonstrates that both the pH value and the S/M ratio are critical parameters for metal removal from the metal citrate (EDTA)-NDDTC(KEtX)system. The study also shows that the ~1H FTNMR can be used successfully to understand the nature of ionic competition and chelate partitioning in these systems.