Cesium Metal Producers

Chemetall GmbH [subsidary of Metallgesell-schaft A.G. part of the Dynamit Nobel Group] 

Wessel, F.W. (1959-1962) Minor Metals and Minerals Caesium and Rubidium. In Mineral Yearbook Vol. I, US Geological Survey, Washington, D.C. 

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The primary producer of cesium metal in the United States is Cabot Corp. 

Cesium metal and cesium compounds are produced and marketed in a variety of grades, eg, from 99% for technical grades to as high as 99.999% for ultrapure compounds. 

Cesium chloride (CsCl) is produced by the reaction of cesium metal with chlorine gas (Ca + Cl —> CsCl). It is also used in the beer brewing industry, to coat fluorescent screens, and to improve the taste of mineral water. 

Cesium hydroxide (CsOH) is the strongest base (alkali) with the highest pH value of any chemical yet found. It is easy to produce by just placing cesium metal in water (which is very reactive). After the hydrogen escapes, cesium hydroxide remains in the water (2Cs + —>... 

The muin source of cesium is camallite KCI MgCL 6H1O which contains a small percentage of cesium compounds. See also Camallite. Cesium also occurs in pollucile (cesium aluminosilicaie, 35% Cs 0) and lepidolite (lithium aluminosilicaie). See also Lepidolite and Pollucile. In early processes, cesium metal was obtained by the reduction of cesium salts, such as Ihe hydroxide or chloride. In current practice, the metal is produced by electrolyzing the cyanide. The latter compound usually is fused cesium barium cyanide mixture. 

Potassium, rubidium, and cesium metals are produced by chemical reduction rather than by electrolysis. Sodium is the reducing agent used in potassium production, and calcium is the reducing agent used for preparing rubidium and cesium. 

As potassium, rubidium, and cesium all produced polymers of about the same microstructure, there may be a general microstructure characteristic of alkali metal-catalyzed polymers. The variations found with sodium polymers and lithium polymers may be caused either by the small size of these atoms or their low electropositivity. 

In addition to the relatively conglomerate structures of the potassium, rubidium, and cesium polymers, there are other characteristics of these polymers, or polymer systems, which may make them unsuitable for practical development as rubbers. The molecular weight of the polymer in these systems decreases as the electropositivity of the metal catalyst increases. Thus, all rubidium and cesium polymers produced so far have been very low in molecular weight. Other disadvantages are the high cost and the safety hazard connected with the use of these metals. 

Bunsen and Kirchhoff had previously discovered cesium in 1860 in the mineral water of Diirkheim, Germany. It was identified based on the bright blue lines in the spectrum. It was the first element to be discovered by spectral analysis. Cesium metal was first produced in 1882 by the electrolysis of cesium chloride. 

The direct metallothermic reduction of pollucite ore with sodium metal is the primary commercial source of cesium metal. In the process, raw pollucite ore is reduced with sodium molten metal at ca. 650"C to form a sodium-cesium alloy containing some rubidium as impurity. Fractional distillation of this alloy in a distillation column at ca. 700"C produces 99.9 wt.% pure cesium metal. Cesium can also be obtained pyrometallurgiccdly reducing the chloride CsCl with calcium metal or the hydroxide CsOH with magnesium metal. Nevertheless, the electrolytic recovery of a cesium amalgam from an aqueous solution of cesium chloride can be achieved in a process similar to the chlor-alkali production with a mercury cathode. Afterwards, the cesium is removed from the amalgam by vacuum distillation. However, cesium metal is produced in rather limited amounts because of its relatively high cost (US 40,800 /kg)... 

Comment on the feasibility of using a reaction similar to (21.4) to produce (a) lithium metal from LiCl (b) cesium metal from CsCl, with Na(l) as the reducing agent in each case. [Hint Consider data from Table 21.2.]... 

Table 2 Hsts examples of compounds with taste and their associated sensory quaUties. Sour taste is primarily produced by the presence of hydrogen ion slightly modified by the types of anions present in the solution, eg, acetic acid is more sour than citric acid at the same pH or molar concentration (43). Saltiness is due to the salts of alkaU metals, the most common of which is sodium chloride. However, salts such as cesium chloride and potassium iodide are bitter potassium bromide has a mixed taste, ie, salty and bitter (44). Thus saltiness, like sourness, is modified by the presence of different anions but is a direct result of a small number of cations.

Cesium was first produced ia the metallic state by electrolysis of a molten mixture of cesium and barium cyanides (2). Subsequentiy the more common thermochemical—reduction techniques were developed (3,4). There were essentially no iadustrial uses for cesium until 1926, when it was used for a few years as a getter and as an effective agent ia reduciag the electron work function on coated tungsten filaments ia radio tubes. Development of photoelectric cells a few years later resulted ia a small but steady consumption of cesium and other appHcations for cesium ia photosensing elements followed. 

Hydrochloric acid digestion takes place at elevated temperatures and produces a solution of the mixed chlorides of cesium, aluminum, and other alkah metals separated from the sUiceous residue by filtration. The impure cesium chloride can be purified as cesium chloride double salts such as cesium antimony chloride [14590-08-0] 4CsCl SbCl, cesium iodine chloride [15605 2-2], CS2CI2I, or cesium hexachlorocerate [19153 4-7] Cs2[CeClg] (26). Such salts are recrystaUized and the purified double salts decomposed to cesium chloride by hydrolysis, or precipitated with hydrogen sulfide. Alternatively, solvent extraction of cesium chloride direct from the hydrochloric acid leach Hquor can be used. 

Work with the Hhpp ligand was pioneered by Cotton and co-workers who showed that the di-metal complexes with Cr(II), Mo(II), or W(II), ionize readily, the latter more readily than cesium [41]. Recent work with the anionic hpp ligand has produced the compound [Au2(hpp)2Cl2] with a short Au-Au (2.47 A) distance [17, 18],... 

Francium s atoms are the largest and heaviest of the alkali metals in group 1 (lA). It is located just below cesium on the periodic table, and thus it is assumed to be an extremely reactive reducing agent even though it is the most scarce of the alkali metals. Its most stable isotope (Fr-223) exists for about 21 or 22 minutes. No one has figured out how to refine francium from natural minerals (ores) because the atoms of the most stable isotope found in nature (Fr-223) are scattered very thinly over the Earth s crust. All of the other 30 isotopes are produced for study by nuclear decay of other radioactive elements. 

Many elements are present in the earth s crust in such minute amounts that they could never have been discovered by ordinary methods of mineral analysis. In 1859, however, Kirchhoff and Bunsen invented the spectroscope, an optical instrument consisting of a collimator, or metal tube fitted at one end with a lens and closed at the other except for a slit, at the focus of the lens, to admit light from the incandescent substance to be examined, a turntable containing a prism mounted to receive and separate the parallel rays from the lens and a telescope to observe the spectrum produced by the prism. With this instrument they soon discovered two new metals, cesium and rubidium, which they classified with sodium and potassium, which had been previously discovered by Davy, and lithium, which was added to the list of elements by Arfwedson. The spectroscopic discovery of thallium by Sir William Crookes and its prompt confirmation by C.-A. Lamy soon followed. In 1863 F. Reich and H. T. Richter of the Freiberg School of Mines discovered a very rare element in zmc blende, and named it indium because of its brilliant line in the indigo region of the spectrum. 

How does the solubility of the alkali metal hydroxides change in the series from lithium to cesium How are the alkali metal hydroxides produced in the industry ... 

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