Particle Image Velocimetry Method for Prediction Hydrodynamic Conditions during Leaching Process on the Basis of Sn–NaOH System

Cwudziński, A.; Gajda, B.

doi:10.3390/ma14030633

Cited by 1 publication

(1 citation statement)

References 35 publications

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“…The lifespan of catalysts varies between 3 to 5 years after which either the precious metals can be extracted from the spent catalysts or they can be regenerated [4]. Hydrometallurgical [5][6][7][8] and pyrometallurgical methods are extensively used at laboratory and industrial scales for the recovery of PGMs from the spent catalysts, while electrochemical techniques are infrequently used [9][10][11][12]. New methods and materials are reported annually.…”

Section: Introductionmentioning

confidence: 99%

Towards Understanding the Cathode Process Mechanism and Kinetics in Molten LiF–AlF3 during the Treatment of Spent Pt/Al2O3 Catalysts

Yasinskiy

Padamata

Stopić

et al. 2021

Metals

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Electrochemical decomposition of spent catalyst dissolved in molten salts is a promising approach for the extraction of precious metals from them. This article reports the results of the study of aluminum electrowinning from the xLiF–(1-x)AlF3 melt (x = 0.64; 0.85) containing 0–5 wt.% of spent petroleum Pt/γ-Al2O3 catalyst on a tungsten electrode at 740–800 °C through cyclic voltammetry and chronoamperometry. The results evidence that the aluminum reduction in the LiF–AlF3 melts is a diffusion-controlled two-step process. Both one-electron and two-electron steps occur simultaneously at close (or same) potentials, which affect the cyclic voltammograms. The diffusion coefficients of electroactive species for the one-electron process were (2.20–6.50)∙10−6 cm2·s–1, and for the two-electron process, they were (0.15–2.20)−6 cm2·s−1. The numbers of electrons found from the chronoamperometry data were in the range from 1.06 to 1.90, indicating the variations of the partial current densities of the one- and two-electron processes. The 64LiF–36AlF3 melt with about 2.5 wt.% of the spent catalysts seems a better electrolyte for the catalyst treatment in terms of cathodic process and alumina solubility, and the range of temperatures from 780 to 800 °C is applicable. The mechanism of aluminum reduction from the studied melts seems complicated and deserves further study to find the optimal process parameters for aluminum reduction during the spent catalyst treatment and the primary metal production as well.

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