Sodium economic importance

Scrap that is unsuitable for recycling into products by the primary aluminum producers is used in the secondary aluminum industry for castings that have modest property requirements. Oxide formation and dross buildup are encountered in the secondary aluminum industry, and fluxes are employed to assist in the collection of dross and removal of inclusions and gas. Such fluxes are usually mixtures of sodium and potassium chlorides. Fumes and residues from these fluxes and treatment of dross are problems of environmental and economic importance, and efforts are made to reclaim both flux and metal values in the dross. 

Most abundant group of materials, composed of silicates of aluminium with sodium, potassium, calcium, and rarely barium. Most economically important mineral. Used for ceramics, glass, abrasive wheels, cements, insulation and fertilizer. 

For many industrial-scale operations involving the oxidation or reduction of both inorganic and organic substances, and especially for the production of the more active metals such as sodium, calcium, magnesium, and aluminum, the most cost-effective reducing agent is electrons supplied by an external power source. The two most economically important of these processes are described below. 

Halides are compounds that include one of the halogen elements fluorine, chlorine, bromine, or iodine. The simplest halides are combinations of one element, such as sodium (Na), with a halogen element, such as chlorine (Cl). Complex halides combine two or more elements with a halogen, and some contain water. Some halides are economically important minerals, such as halite (common salt), fluorite (fluorine), and chlorargyrite (silver ore). 

Economic Importance-. The manufacture of elemental sodium is closely coupled to the utilization of lead-containing antiknock agents for Otto motor fuels and is therefore now of only minor importance (due to environment protection legislation). In the USA, by far the most important producer country, the consumption declined 5.4% per year between 1975 and 1996. The worldwide capacity (without Eastern Europe) was 250 10 t/a at the end of the 1970 s, of which about two thirds was in the USA. The production in the USA in 1996 was only ca. 24 10 t, compared with 155 10 t in 1970. 

Economic Importance The production of sodium hydrogen carbonate is much lower than that of sodium carbonate. The production in the USA in 1995 was 0.454 10 t being only ca. 5% of the sodium carbonate production and corresponding to 50% of the world production of 0.895 10 t. The capacity in the USA has expanded considerably in recent years and as a result production should increase by 2% per year in coming years. A plant for producing sodium hydrogen carbonate from natural deposits came on stream in the USA in 1991. 

Sodium is present in many compounds that have great economic importance. One of the most well-known compounds is salt, or sodium chloride (NaCl). Approximately 20 million tons of salt is produced every year through the mining of salt deposits all over the world. Salt is also extracted from seawater, although in lower amounts than are available from salt mine deposits. 

Sodium, economically much the most important of the alkali metals, is manufactured by the Downs process in which... 

Sodium compounds are of enormous economic importance. Common table salt, which is sodium chloride, has been an important article of commerce since earliest recorded history. Salt was of such importance in Roman times that a specific allowance of salt... 

The addition of ascorbic acid (or sodium ascorbate or ascorbyl palmitate) to meat and meat products together with nitrites (at a level of 60-180 mg/kg), for example, in the production of ham, is of functional and economic importance as it enhances and speeds up its production considerably. The characteristic pigment of raw meat treated with nitrites, nitroxymyoglobin, is formed approximately three times faster. The addition of ascorbic acid allows the time of smoking to be shortened and stabilises the colour of the finished... 

Comparison to the Raschig Process. The economics of this peroxide process in comparison to the Raschig or hypochlorite—ketazine processes depend on the relative costs of chlorine, caustic, and hydrogen peroxide. An inexpensive source of peroxide would make this process attractive. Its energy consumption could be somewhat less, because the ketazine in the peroxide process is recovered by decantation rather than by distillation as in the hypcochlorite process. A big advantage of the peroxide process is the elimination of sodium chloride as a by-product this is important where salt discharge is an environmental concern. In addition to Elf Atochem, Mitsubishi Gas (Japan) uses a peroxide process. 

Sulfur Dyes. These dyes ate appHed to cottoa from an alkaline-teduciag bath with sodium sulfide as the reduciag ageat. NumeticaUy this is a relatively smaU group. However, the low cost and good washfastness properties of the dyeiags make this class important from an economic standpoiat (see SULFURDYES). 

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