Castner cells

Cast-link belt furnaces Cast molding Castner cell Castner process... 

Electrolysis of Fused Sodium Hydroxide. The first successful electrolytic production of sodium was achieved with the Castner cell (2) ... 

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). 

Castner cell, 22 767, 768-769, 772 Cast nickel-beryllium alloys, 3 657t, 658t Castor oil, 2 82 9 143 10 817, 820-822 cosmetically useful lipid, 7 833t in cosmetic molded sticks, 7 840t in defoamer formulations, 3 237-238 dehydrated, 9 150... 

Electrolysis of fused sodium hydroxide has heen achieved successfully with a Castner cell. The Castner cell was used in commercial production prior to introduction of Downs cell. The cell is operated at a bath temperature 320 10°C, at 9.0 0.5 amp current and a voltage of 4.3 to 5.0 V. The cathode current density is about 10.9 kA/m2. The cell consists of a copper cathode and a nickel anode and a cylindrical iron-gauge diaphragm placed between the electrodes. The cell reactions are as follows ... 

Castner cell -for sodium [SODIUMAND SODIUM ALLOYS] (Vol 22)... 

Castner cell — (also Castner-Kellner cell) Electrochemical cell employed in sodium winning by electrolysis of molten NaOH. According to... 

The first, and now obsolete, industrial processes for producing raw sodium metal were based on the carbon reduction of sodium carbonate or sodium hydroxide. The first industrial production of pure sodium metal was performed by molten-salt electrolysis of the pure sodium hydroxide, NaOH, in so-caUed Castner cells. Most modern processes for the production of sodium now involve molten-salt electrolysis of highly pure sodium chloride. Actually, since 1921, when the process was invented by J.C. Downs, the electrolysis has been performed in Downs electrolytic cells at the DuPont de Nemours Canadian facilities at Niagara Falls, Ontario, Canada. The electrolytic cell consists of four cylindrical anodes made of graphite surrounded at the bottom of the cell by steel cathodes, and a fine steel mesh acts as a separator between anodic and cathodic compartments. Each cell contains a batch of 8 tonnes of a molten-salt mixture with the following chemical composition NaCl (28 wt.%), CaCl (26 wL%), and BaClj (46 wt.%). 

Castner-Kellner cell An electrolytic cell for the production of sodium hydroxide. ... 

Manufacture is either by reaction of molten sodium with methyl alcohol or by the reaction of methyl alcohol with sodium amalgam obtained from the electrolysis of brine in a Castner mercury cell (78). Both these methods produce a solution of sodium methylate in methanol and the product is offered in two forms a 30% solution in methanol, and a soHd, which is a dry, free-flowing white powder obtained by evaporating the methanol. The direct production of dry sodium methylate has been carried out by the introduction of methanol vapors to molten sodium in a heavy duty agitating reactor. The sohd is supphed in polyethylene bags contained in airtight dmms filled in a nitrogen atmosphere. 

H. Y. Castner (US/UK) and C. Kellner (Vienna) independently developed commercial mercury-cathode cell for chlor-alkali production... 

In 1885, Charles Martin Hall invented his aluminum process and Hamilton Young Castner in 1890 developed the mercury-type alkali-chlorine cell, which produced caustic (sodium hydroxide) in its purest form. Edward G. Acheson in 1891, while attempting to make diamonds in an electric furnace, produced silicon carbide, the first synthetic abrasive, second to diamond in hardness. Four years later, Jacobs melted aluminum oxide to make a superior emeiy cloth. Within two decades, these two abrasives had displaced most natural cutting materials, including naturally occurring mixtures of aluminum and iron oxides. 

Griesheim (1) An early process for producing chlorine by electrolysis, developed by Chemische Fabrik Griesheim-Elektron, in Germany, and commercialized in 1890. The electrolyte was saturated potassium chloride solution, heated to 80 to 90°C. The byproduct potassium hydroxide was recovered. The process was superseded in the United States by several similar electrolytic processes before being ousted by the mercury cell, invented by H. Y. Castner and K. Kellner in 1892. See Castner-Kellner. 

Membrane cell A refinement of the Diaphragm cell process in which the diaphragm is made from a cation-exchange membrane. See also Castner-Kellner. 

Castner Kellner Cell.—Besides those cells already described, the object of which is to produce oxygen and hydrogen, there are some which, thongh not designed for the production of hydrogen, yield it as a by-product... 

Sodium was first isolated by Sir Humphry Davy in 1807 by electrolysis of caustic soda. In the following year. Gay Lussac and Thenard obtained metallic sodium by chemical reduction of caustic soda with iron at elevated temperatures. Deville, in 1854, prepared the metal by reduction of sodium carbonate and lime with charcoal at a temperature above the boiling point of sodium. Castner, in 1886, improved the chemical reduction process preparing the metal by heating sodium hydroxide with iron carbide at high temperature. Five years later he patented a process based on electrolytic reduction of sodium hydroxide. The first major commercial plant was set up in 1921 with the introduction of Downs cell. 

Castner turned his interest to gold extraction, which required high-quality sodium hydroxide. Castner developed a three-chambered electrolytic cell. The two end chambers contained brine and graphite electrodes. The middle chamber held water. The cells were separated excepted for a small opening on the bottom, which contained a pool of mercury that served as the cell s cathode. When current flowed through the cell and the cell was rocked, sodium reduced from the brine came into contact with water in the middle cell to produce a sodium hydroxide solution. As Castner built his mercury cell, Kellner was working on a similar design. Rather than compete with each other, Castner and Kellner joined forces to establish the Castner-Kellner Alkali Company to produce sodium hydroxide, which competed with soda ash and potash as an industrial base, and chlorine, which was used primarily to make bleach. 

Contemporary mercury cells are based on the original designs of Castner and Kellner. Mercury is used as the cathode. Sodium produced forms an amalgam, which passes to a water chamber. Here graphite is used to catalyze the dissociation of sodium from the mercury. The sodium reacts with water to produce sodium hydroxide according to the reaction 2Na(s) + 2H —> 2NaOH. + H. .. 

Chlorine gas is produced by the electrolysis of brine (sodium chloride) in Castner-Kellner cells (first operated in 1886), the main purpose of which is the production of sodium hydroxide solution. Williams (1972, p98) reports that the extent to which the Castner-Kellner process was worked in Britain depended on the ability to dispose of the chlorine. In this light the production of chlorinated organic compounds can be seen as a response to the need to use chlorine. The argument that we need to produce chlorinated organic compounds to use up chlorine was indeed put to me by manufacturers of polyvinyl chloride (PVC) at a DETR-organized seminar on the lifecycle assessment of PVC in July 2001 PVC is the only product made in sufficient quantities to use up all the chlorine produced by other processes. This suggests that if a particular use of a chemical is stopped, because there is a better (less hazardous) way of achieving that purpose, it will have knock-on effects on the availability of chemicals that are co-produced... 

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