Types of Electrolytic Cells

Main types of electrolytic cells are shown in Figs. 58—62. 

According to Fig. 58 both electrodes, A and K are placed in a closed container 0 and separated by diaphragm D. Fig. 5 ) represents a simple type whore the opposite walls of the electrolytic cell act as anode and cathode these walls are separated from other metallic parts of the electrolyzer by means of insulating packing B. In the electrolytic cell shown in Fig. 60 the separation of gases is 

A — Anode, K — Cathode, O — A — Anode, K — Cathode, D — A — Anode, K — Oa-Bleotrolytdoreaacl.D—Diaphragm. Diaphragm, B — Insulation. thodo, F — Bell-Jar. 

As already said neither acids nor salts are suitable for lowering the specific resistance of water because of their corrosive effect. ) Therefore only sodium or 

The specific resistance of both hydroxides decreases with increasing concentration to a certan minimum which depends on the temperature. From this it can be deduced that the concentration of the electrolyte should correspond to the assumed temperature of the electrolyte, if the resistance of the bath is to 

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Conversion of aqueous NaCl to Cl and NaOH is achieved in three types of electrolytic cells the diaphragm cell, the membrane cell, and the mercury cell. The distinguishing feature of these cells is the manner by which the electrolysis products are prevented from mixing with each other, thus ensuring generation of products having proper purity. 

Chloiine is pioduced at the anode in each of the three types of electrolytic cells. The cathodic reaction in diaphragm and membrane cells is the electrolysis of water to generate as indicated, whereas the cathodic reaction in mercury cells is the discharge of sodium ion, Na, to form dilute sodium amalgam. 

Fluorine was first produced commercially ca 50 years after its discovery. In the intervening period, fluorine chemistry was restricted to the development of various types of electrolytic cells on a laboratory scale. In World War 11, the demand for uranium hexafluoride [7783-81-5] UF, in the United States and United Kingdom, and chlorine trifluoride [7790-91 -2J, CIF, in Germany, led to the development of commercial fluorine-generating cells. The main use of fluorine in the 1990s is in the production of UF for the nuclear power industry (see Nuclearreactors). However, its use in the preparation of some specialty products and in the surface treatment of polymers is growing. 

Manganate(VI) formed in the initial oxidation process must first be dissolved in a dilute solution of potassium hydroxide. The concentrations depend on the type of electrolytic cell employed. For example, the continuous Cams cell uses 120 150 g/L KOH and 50 60 g/L K MnO the batch-operated Bitterfeld cell starts out with KOH concentrations of 150 160 g/L KOH and 200 220 g/L K MnO. These concentration parameters minimize the disproportionation of the K MnO and control the solubiUty of the KMnO formed in the course of electrolysis. 

This type of electrolytic cell consists of anodes and cathodes that are separated by a water impermeable ion-conducting membrane. Brine is fed through the anode where chlorine gas is generated and sodium hydroxide solution collects at the cathode. Chloride ions are prevented from migrating from the anode compartment to the cathode compartment by the membrane and this, consequently, leads to the production of sodium hydroxide, free of contaminants like salts. The condition of the membrane during operation requires more care. They must remain stable while being exposed to chlorine and strong caustic solution on either side they must allow, also, the transport of sodium ions and not chloride ions. 

Other types of electrolytic cells, although not so commonly used today, are also known. In a diaphragm type cell that separates the cell into anode and cathode compartments, an aqueous solution of potassium chloride is electrolyzed. Potassium hydroxide and hydrogen are produced at the cathode and chlorine is hberated at the anode. The solution discharged from the cell is... 

Sodium hydroxide is manufactured together with chlorine by electrolysis of sodium chloride solution. Various types of electrolytic cells are used commercially. They include the mercury cell, the diaphragm cell, and the membrane cell. 

The usual diaphragm type of electrolytic cell is used in all of the experiments except those at a boiling temperature. (Experiment No. 10, Table 1.) The coll is immersed in a cooling mixture or cold water to maintain the desired temperature. A mechanical stirrer is used in all experiments. Unless otherwise stated, the mercury layer is not stirred with the mechanical stirrer. In all cases a platinum spiral anode is used. 

As discussed in the Introduction section, three main types of electrolytic cells have been used for the large scale production of chlorine and caustic soda mercury, diaphragm and membrane cells. The main difference in these technologies lies in the manner by which the chlorine gas and the sodium hydroxide are prevented from mixing with each other to ensure generation of pure product. Alternatively, the electrolysis of hydrochloric acid solutions is also used to produce chlorine. Individual electrolysis cells can be electrically wired in parallel (monopolar electrolysers) or in series (bipolar electrolysers). 

Chlorine and sodium hydroxide (caustic soda) are among the top ten chemicals produced in the world. They are used as raw materials in the manufacturing of a wide variety of products (e.g., pharmaceuticals, detergents, deodorants, disinfectants, herbicides, pesticides and plastics). From a historical perspective, three main types of electrolytic cells have been used... 

Over 95% of the world s chloralkall production is achieved by the electrolysis of sodium chloride solution. The products are chlorine, caustic soda, and some hydrogen. The main types of electrolytic cells currently available are mercury, membrane, and diaphragm. The most commonly used in North America is the diaphragm cell (CIS, 1999). In Western Europe, the mercury cell is most commonly used, and in Japan the membrane cell is used because it requires much less energy. 

The type of electrolytic cell commonly used in these marine and offshore applications is a tube within a tube , (but there are a variety of configurations.) A tube within a tube type cell consists of one anode, one cathode, and one bipolar tube with the necessary ancillary hardware to facilitate assembly-see Fig. 1. The outer anode and cathode are manufactured firom seamless titanium pipe. The anode surface is coated with proprietary precious metal oxides, primarily ruthenium and iridium. Seawater enters one end of the cell and passes between the cathode, the anode and bipolar tube annular spaces. When direct current is applied to the cell, sodium hypochlorite results. One cell can produce up to 5.5 kg/day and a maximum of 12 cells can be connected in series for a capacity of 65 kg/day per train. Multiple trains can operate in parallel to produce the required capacity. 

Oxidation of SO2 in the absorber varied from 7 to 25%. As a result of the oxidation, it is necessary to have two types of electrolytic cells. A three compartment (A type) cell is the basic design that converts sodium sulfate into caustic soda and an impure sulfuric acid solu-... 

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