Rotating cylinder electrode reactor

Robinson and Walsh have reviewed earlier cell designs. The performance of a 500 A pilot plant reactor for copper ion removal is described. Simplified expressions were derived for mass transport both in single pass [243] and batch recirculation [244]. For a detailed discussion of the principle and the role of the rotating cylinder electrode reactor in metal ion removal the reader is referred to Refs. [13] and [241] (46 references). 

Walsh FC, The role of the rotating cylinder electrode reactor in metal ion removal in ref (23), p 101, and references therein... 

Robinson D, Walsh FC (1991) The performance of a 500 Amp rotating cylinder electrode reactor, Part 1. Current-potential data and single pass studies, Hydrometallurgy 26 93 Chem Abstr 114 (1991) 194767w... 

Figure 9. A pilot scale rotating cylinder electrode reactor system for continuous extraction of cadmium powder from hydrometalliu gical process streams [40].

Gahe, D.R. and Walsh, RC. (1990) Recovery of metal from industrial process liquors using a rotating cylinder electrode reactor. Institute of Chemical Engineering Symposium Series, 116, 219-229. 

Terrazas-Rodilguez, J.E., Gutierrez-Granados, S., Alatorre-Ordaz, M.A. et al. (2011) A comparison of the electrochemical recovery of paUadium using a paraUel flat plate flow-by reactor and a rotating cylinder electrode reactor. Eiectrochimica Acta, 56, 9357-9363. 

Alonso Alejandro R, Lapidus GT, Gonzalez I (2008) Selective silver electroseparation from ammoniacal thiosulfate leaching solutions using a rotating cylinder electrode reactor (RCE). Hydrometallurgy 92 115-123. doi 10.1016/j.hydromet.2008.02.001... 

High mass-transport coefficients are obtained in cells with a rotating cylinder electrode (RCE) and a small gap between the anode and the cathode, Fig. 4(a). High rates of mass transport are experienced in the turbulent flow regime, so that RCE reactors allow metal deposition at high speed, even from dilute solutions. RCE reactors have been operated at a scale involving diameters from 5 to 100 cm, with rotation speeds from 100 to 1500 rpm and currents from 1 A to 10 kA [79], It... 

For the rotating cylinder electrode to be adopted as a continuous reactor, some degree of axial flow has to be superimposed on the tangential and turbulent motion in the annulus (Fig. 2.8b). If the rate of mass transport due to axial flow exceeds that due to rotation then the reactor will exhibit approximate plug-flow characteristics. If the reverse is true the behavior will tend to approach that of a continuous stirred-tank reactor (see Section 5.1.1.1). 

Fig. 7.8 Treatment of a 100 mg dm " Cu solution by four 2 kA Eco cells in series and operating under identical conditions. In rotating-cylinder electrode cells, high fractional conversion may be obtained by (a) employing a number of separate reactors in hydraulic series or more practically (b) by the Eco Cascade cell.

Several of these studies were conducted in an electrochemical batch reactor that had a rotating-cylinder anode (RCA). Since the anode was operated below the limiting current for mediator generation, relatively high coulombic efficiencies were achieved. Ion-exchange membranes were used to separate electrodes in Ag(II)-based processes, but were eliminated in processes based upon Co(III) and H2SO4. Rates of CO2 generation were measured and used to... 

Figure 2.2 Elementary cell geometries (a) parallel-plate cell, (b) rotating cylinder in tube cell, (c) two plates in reactor cell, and (d) plate cell with non-parallel electrodes.

Electrochemical reactors (cells, tanks) are used for the practical realization of electrolysis or the electrochemical generation of electrical energy. In developing such reactors one must take into account the purpose of the reactor as well as the special features of the reactions employed in it. Most common is the classical reactor type with plane-parallel electrodes in which positive and negative electrodes alternate and all electrodes having the same polarity are connected in parallel. Reactors in which the electrodes are concentric cylinders and convection of the liquid electrolyte can be realized by rotation of one of the electrodes are less common. In batteries, occasionally the electrodes are in the form of two long ribbons with a separator in between which are wound up as a double spiral. 

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