Removal of impurities from lead-trilonate solutions with regeneration of the solvent

Electroextraction of lead from a lead trilonate solution

“…It was shown previously [2] that the ligand config uration changes at various pH of the ethylenediamine tetraacetate solution, namely, ions H 3 EDTA -and H 2 EDTA 2-are present in the solution at pH = 4; H 2 EDTA 2-ions are preferentially observed at pH = 7; and EDTA 4-ions prevail at pH = 10. In connection with this fact, the electroreduction process itself depends on the strength of existing complexes, on their charge, and on the electrical conductivity of the electrolyte (which decreases in the alkali medium pro portionally to the concentration of hydrogen ions).…”

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The method of extracting lead into a solution from lead cakes of zinc production and the removal of metal impurities from the thus prepared solution were sug gested in [1,2]. We used a complex former, namely, dis odium salt of ethylenediamine acid known as Trilon B, as the leaching reagent.

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“…We used a silverchlorine half cell as the reference electrode. The working electrode with an area of 0.5024 cm 2 , which was fabricated from stainless steel and pressed into a vinyl plastic holder, was separated from the reference electrode using an electrolytic key. The platinum electrode was an auxiliary electrode.…”