Electrolysis rectangular cell

The first production plant in the world for electrolytic aluminum coating from organoaluminum complexes was put into operation by SEDEC (Berlin) in 1983. In order to shorten the processing time required by the HGA plant, this unit was designed as a rectangular cell. The production cell has an electrolyte volume of 15,000 L. The capacity of this automatic aluminum plating unit amounts to 32 m /h, with a layer thickness of 10 pm. Articles mounted on 32 frames, each 500 X 1000 mm in size, can be simultaneously coated. Fig. 19 shows the electrolysis... 

It was an adaptation of the Castner cell to sodium chloride for fused caustic electrolysis. A mixture of sodium chloride and other chlorides, molten at 620°C, was electroly2ed ia rectangular or oval cells heated only by the current. Several cells have been patented for the electrolysis of fused salt ia cells with molten lead cathodes (65). However, it is difficult to separate the lead from the sodium (see Electrochemical processing). 

The electrodeposition of CdS films on conductive substrates from aqueous solutions is a low-cost process, which is well suited for the preparation of film solar cells. Polycrystalline CdS films of good quality were obtained by electrolysis with rectangular voltages on indium... 

The cell for this electrolysis consists of a closed, rectangular, refractory-lined steel box with a carbon anode and an iron cathode. The anode and cathode are arranged in separate compartments to facilitate the recovery of the sodium and the chlorine. Sodium chloride has a high melting point (804°C), but calcium chloride is added to lower it, and the cell is operated at 600°C. The electrolyte is a eutectic of 33.3% sodium chloride arid 66.7% calcium chloride. 

Into a freshly charged cell, as previously prepared, place 300 milliliters (10.1 fluid oz.) of ice-cold tap water into the anode compartment (clay pot), and then add and dissolve 50 grams (1.8 oz.) of sodium chlorate into this water. Thereafter, place 500 milliliters (17 fluid oz.) of ice-cold tap water into the cathode compartment, and then add and dissolve 50 grams (1.8 oz.) of sodium chlorate there into. Thereafter assemble the cell as illustrated below, and then place the cell into an ice bath, and then begin the electrolysis process. The desired dimensions of the titanium electrodes may vary, but it is recommended to use rectangular bars of 10 to 15 millimeters in width of surface area (0.39 inches by 0.59 inches), and the electrodes should be placed about 127 millimeters apart (5 inches). The current should be 1.5 to 2.7 volts DC current at about 50 amps. Over voltage should be minimum, and the cell temperature should be kept below 5 Celsius at all times. Electrolyze the solution for about 18 to 24 hours. 

Electrolysis cells may be either monopolar or bipolar, rectangular, or circular and operated batchwise or continuously. Typical parameters are KMnO -content in the electrolyte 120-250 g L 1, cell... 

Alumina electrolysis cells consist of a rectangular steel shell lined with a 25-35 cm layer of baked and rammed dense carbon, which provides both chemical resistance and the cathode contact with the electrolyte via steel bus bars imbedded in the carbon. Normal lining life is 4—6 years, after which it is replaced as large preformed slabs. Once a reduction pot has been started the bulk of the cathode current to the carbon lining is via the pool of newly formed molten aluminum in the bottom of the cell (Fig. 12.2). 

A Hall-Heroult electrolytic cell consists of a rectangular steel shell hned first with an insulating material, then with carbon (from baked petroleum coke) to form the negative electrode (Figure 13.12). The other (positive) electrode is also made from carbon. The electrolyte consists of molten cryolite, at about 1000°C, into which some aluminum oxide is dissolved. The overall electrolysis reaction is... 

The electrolysis cell with vertical electrodes shown in Figure 1.4.4 also uses inert anodes and wettable cathodes [12], Several cells with vertical electrodes have been proposed in the literature [6, 14-19] but all these cells have electrodes with a rectangular shape and cathodes immersed into the aluminium pool. The electrodes proposed in Figure 1.4.4 are of trapezoid shape, by which the oxygen escape and aluminium flow are facilitated. It also provides better separation between the electrolysis products, and therefore the current efficiency is higher. Another advantage of the proposed cathodes is that they are not in contact with the aluminium pool, are movable in the horizontal and vertical direction, and are easily changeable. 

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