Voltammetry of nickel in molten lithium fluoride-sodium fluoride-potassium fluoride

Abstract Results are presented on the rapid scan voltammetry and anodic stripping voltammetry of nickel in molten LiF-NaF-KF. The technique of anodic stripping voltammetry is promising as a means of determining trace quantities of nickel directly in the melt; as little as 1 p.p.m. can be detected. The half-wave potential for the reduction of Ni(II) → Ni(0) occurs at approximately −0.2 V vs . the platinum quasi-reference electrode. Current-voltage curves were recorded at a pyrolytic graphite indicator electrode at voltage scan rates from 50 mV/min-10 V/min. At the faster scan rates, peak-shaped curves resulted which indicated that the transport process was mainly diffusion-controlled. A diffusion coefficient of 1·10 −6 cm 2 /sec at 500° was calculated. An activation energy of about 18 kcal/mole was calculated for the current-limiting process which corresponds to the reduction of Ni(II) to the metal.