Chemical Engineering Research and Design 1 5 0 ( 2 0 1 9 ) 40–48 Contents lists available at ScienceDirect Chemical Engineering Research and Design journal homepage: www.elsevier.com/locate/cherd The investigation of stoichiometry and kinetics of cerium (IV) solvent extraction from sulfate medium by Cyanex 272 and 301 using single drop column Raoof Bardestani a , Mohammad Kavand b,* , Mahdi Askaripour b a Department of Chemical Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, Québec G1V 0A6, Canada b Department of Mining, Metallurgy, and Material Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, Québec G1V 0A6, Canada a r t i c l e i n f o Article history: Received 19 February 2019 Received in revised form 16 July 2019 Accepted 18 July 2019 Available online 31 July 2019 Keywords: Liquid–liquid extraction Cations separation Organophosphorus extractants Extraction columns Single droplet a b s t r a c t In the present study, the solvent extraction of cerium (IV) from sulfate medium was inves- tigated by Cyanex 272 and 301. The main objective was to increase our understanding of the behavior of analogous extractants, but different in donor atom, which were achieved by batch and kinetics investigations. This allows better selection of extractants for simi- lar approaches in future works. The investigation of extraction kinetics using single drop columns provides this work with a simpler approach in term of overall procedure for the separation of cerium ions from aqueous solutions, which allows finding how experimental conditions control the rate of reaction. The effects of parameters such as pH, extractant concentration, organic to aqueous volume, and temperature were studied under batch con- ditions. The complete extraction of 200 mg L −1 Ce (IV) at pH of 4 was obtained either by Cyanex 272 or 301 diluted in kerosene. Results shows that regarding the structural substitu- tion of oxygen with sulfur, Cyanex 272 has a better performance in a lower concentration, while Cyanex 301 shows higher extraction percentage at lower pH. The extraction by Cyanex 272 and 301 was exothermic and endothermic, respectively. Results of reaction kinetics revealed that by considering the correction of droplets residence time, the rate of extraction either by Cyanex 272 or 301 is independent of the height of the column. Thus, the effects of extractants and cerium concentrations along with the pH of aqueous solution allowed find- ing the rate of extraction. The cerium mass flux increased by droplet diameter, indicating the contribution of mass diffusion in the extraction. © 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. 1. Introduction Cerium is the most abundant rare earth element normally found in bastnasite ((Ce, La)CO 3 F) and Monazite-(Ce) ((Ce, La, Nd, Th)PO 4 ). Cerium (IV) oxide or ceria is the most commonly used compound of cerium, typically applied as a catalyst to convert CO and NO X releasing in the automobiles exhaust, into CO 2 and N 2 , respectively. The recovery of cations from acidic ∗ Corresponding author. E-mail addresses: Raoof.Bardestani.1@ulaval.ca (R. Bardestani), Mohammad.kavand.1@ulaval.ca (M. Kavand), Mahdi.Askaripour.1@ulaval.ca (M. Askaripour). leached ore is an essential step to obtain highly concentrated cerium accomplished by adsorption, solvent extraction, ion exchange, crystallization, and precipitation (Bardestani et al., 2019; Bardestani and Kaliaguine, 2018; Kavand et al., 2017; Shi et al., 2017a). Among the techniques, solvent extraction also used in food processing, is a method of metal recovery on a large scale, regarding its advantages such as simplic- ity, affordable cost, higher selectivity and pureness, less waste https://doi.org/10.1016/j.cherd.2019.07.014 0263-8762/© 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.