Sodium metallurgy

Sodium Metallurgy Sodium metal is obtained by the electrolysis of molten, or fused, sodium chloride. Sodium chloride is mined from huge underground deposits. The other source of sodium chloride is seawater, which is a solution of many dissolved substances, but sodium chloride is the principal one. Sodium chloride melts at 801°C, but commercial electrolysis employs a mixture of NaCl and CaCl2, which melts at 580°C. We discussed the electrolysis in some detail in Section 20.9. ... 

Sihcon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between sihcon carbide and a variety of compounds at relatively high temperatures. Sodium sihcate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal sihcide. Sihcon carbide decomposes in fused alkahes such as potassium chromate or sodium chromate and in fused borax or cryohte, and reacts with carbon dioxide, hydrogen, ak, and steam. Sihcon carbide, resistant to chlorine below 700°C, reacts to form carbon and sihcon tetrachloride at high temperature. SiC dissociates in molten kon and the sihcon reacts with oxides present in the melt, a reaction of use in the metallurgy of kon and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new sihcon nitride-bonded type exhibits improved resistance to cryohte. 

Sodium cyanide [143-33-9] NaCN, is a white cubic crystalline soHd commonly called white cyanide. It was first prepared in 1834 by heating Pmssian blue, a mixture of cyanogen compounds of iron, and sodium carbonate and extracting sodium cyanide from the cooled mixture using alcohol. Sodium cyanide remained a laboratory curiosity until 1887, when a process was patented for the extraction of gold and silver from ores by means of a dilute solution of cyanide (see Metallurgy, extractive). A mixture of sodium and potassium cyanides, produced by Edenmeyer s improvement of the Rodgers process, was marketed in 1890. 

Hydrogen sulfide has a variety of industrial uses. Its major use is in the production of elemental sulfur and sulfuric acid. Hydrogen sulfide is also used in the manufacture of sodium sulfide and thiophenes. It is used in metallurgy and in the production of heavy water for the nuclear industry (Beauchamp et al. 1984 HSDB 1998). In the past, hydrogen sulfide was used as an agricultural disinfectant. 

Chemical manufacturing sodium sulfide in, 23 639 key characteristics of, 11 440t safety in, 21 826-827 safety legislation related to, 21 827-828 Chemical mapping, AES, 24 106 Chemical Marketing Research Association (CMRA), 15 645-646 Chemical metallurgy, 16 126 Chemical methods... 

The most important applications of hydrogen sulfide involve the production of sodium sulfide and other inorganic sulfides. Hydrogen sulfide obtained as a by-product often is converted into sulfuric acid. It also is used in organic synthesis to make thiols or mercaptans. Other applications are in metallurgy for extracting nickel, copper, and cobalt as sulfides from their minerals and in classical qualitative analytical methods for precipitation of many metals (see Reactions). It also is used in producing heavy water for nuclear reactors. 

Carl Friedrich Plattner was bom in 1800 at Klein-Waltersdorf near Freiberg, was educated at the Freiberg School of Mines, and became a professor of metallurgy and blowpipe analysis there. He was a great master of the art and science of analytical chemistry, and applied the blowpipe even to quantitative analysis. He made many promising experiments on the oxidation of sulfur dioxide to the trioxide by means of catalysts. Before the work was completed, however, he was stricken with apoplexy, which terminated fatally in 1858 (68). When F lix Pisani (1831—1920) examined pollucite four years after the discovery of cesium, he found that Plattner had mistaken his cesium sulfate for a mixture of the sulfates of sodium and potassium (8, 37, 58). 

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Cyanide. Potassium cyanide, [CAS 151-50-8], cyanide of potash, KCN, white solid, soluble, very poisonous, formed by reaction of calcium cyanamide and potassium chloride at high temperature. Used as a source of cyanide and for hydrocyanic acid, but usually replaced by the cheaper sodium cyanide. Also used in metallurgy, electroplating,... 

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