Rubidium extraction

CALCINATION FACTORS OF RUBIDIUM EXTRACTION FROM LOW-GRADE MUSCOVITE ORE... 

Calcination Factors of Rubidium Extraction from Low-Grade... 

Hypnea muscifonnis extract (35% of the weed) does not gel without solutes, especially electrolytes. The most effective salts are those containing cesium, rubidium, potassium, and ammonium ions (in that order). Gel strengths were greater than for agar at the same concentrations. 

Shen and Ii [149] extracted caesium (and rubidium) from brine samples with 4-tert-butyl-2-(a methyl-benzyl) phenol prior to atomic absorption spec-trometric determination of the metal. 

One problem in refining cesium is that it is usually found along with rubidium therefore, the two elements must be separated after they are extracted from their sources. The main process to produce cesium is to finely grind its ores and then heat the mix to about 600°C along with liquid sodium, which produces an alloy of Na, Cs, and Ru, which are separated by fractional distillation. Cesium can also be produced by the thermochemical reduction of a mixture of cesium chloride (CsCl) and calcium (Ca). 

Rubidium is recovered from its ore lepidolite or pollucite. Mineral lepidolite is a lithium mica having a composition KRbLi(OH,F)Al2Si30io. The ore is opened by fusion with gypsum (potassium sulfate) or with a mixture of barium sulfate and barium carbonate. The fused mass is extracted with hot water to leach out water-soluble alums of cesium, rubidium, and potassium. The solution is filtered to remove insoluble residues. Alums of alkali metals are separated from solution by fractional crystallization. Solubility of rubidium alum or rubidium aluminum sulfate dodecahydrate, RbAl(S04)2 I2H2O falls between potassium and cesium alum. 

Uses Of the Stassfurt salts.—The magnesium compounds in the Stassfurt salts are used for the preparation of magnesium and of its salts. The potash salts are an essential constituent of many fertilizers used in agriculture, etc. 22 and potassium chloride is the starting-point for the manufacture of the many different kinds of potassium salts used in commerce—carbonate, hydroxide, nitrate, chlorate, chromate, alum, ferrocyanide, cyanide, iodide, bromide, etc. Chlorine and bromine are extracted by electrolysis and other processes from the mother liquids obtained in the purification of the potash salts. Boric acid and borax are prepared from boracite. Caesium and rubidium are recovered from the crude carnallite and sylvite. 

Lithium, rubidium, and caesium.—F. C. Robinson and C. C. Hutchins 7 extracted all three alkalies—lithium, rubidium, and caesium—by decomposing the mineral with fluorspar in the following manner ... 

Precipitate with aq. ammonia. Evaporate the soln. down to about 100 c.c., and filter the ot liquid so as to remove calcium sulphate. The cone. soln. is sat. with ammonium alum and allowed to stand for some time. The mixed crystals of potassium, rubidium, and oeesium alums and of lithium salt are dissolved in 100 c.c. of distilled water and recrystal-lized. The recrystallization is repeated until the crystals show no spectroscopic reaction for potassium or lithium. The yield naturally depends on the variety of lepidolite employed. 100. grms of an average sample gives about 10 grms. of crude crystals and about 3 grms. of the purified caesium and rubidium alums. For the purification of caesium and rubidium salts, see the chlorides. The mother-liquors are treated with an excess of barium carbonate, boiled, and filtered. The filtrate is acidified with hydrochloric acid, and evaporated to dryness. The residue is extracted with absolute alcohol in which lithium chloride is soluble, and the other alkali chlorides are sparingly soluble. 

Ccesium Niobates.—Fusion of niobium pentoxide and caesium carbonate and extraction of the melt with water yields monoclinic crystals which have the composition 4Cs20.3Nb205.14H20, and which are iso-morphous with the rubidium salt. Addition of alcohol to the aqueous solution furnishes crystals of 7Cs2O.6Nb2O5.80H2O. ... 

Rubidium Niobates.—When niobium pentoxide is fused with rubidium carbonate and the melt is extracted with water, fine, silky needles of composition 3Rb20.4Nb205.9 Ha0 are left behind. Concentration of the filtrate yields monoclinic crystals of 4Rb20.3Nba0B. 14H20, which are isomorphous with the corresponding tantalum salt and with the corresponding caesium niobate and tantalate. a b c= 0-8815 1 1-0491 j3=95° 53. It slowly loses some of its water on exposure to- air.3... 

Oxalo-niobates or niobo-oxalates correspond to the vanado-oxalates, and contain both oxalic acid and niobic add radicals in the complex anion. The only known series possesses the general formula 3R aO. Nb 205.6C203.a H20, where R stands for an alkali metal. The sodium, potassium and rubidium salts are prepared by fusing one molecular proportion of niobium pentoxide with three molecular proportions of the alkali carbonate in a platinum crucible. The aqueous extract of the melt jjs poured into hot oxalic add solution concentration and cooling, or addition of alcohol or acetone, then brings about precipitation of the complex salt. Comparison of the dectrical conductivity measurements of solutions of the alkali oxalo-niobates with those of the alkali hydrogen oxalates determined under the same conditions indicates that the oxalo-niobates are hydrolysed in aqueous solution, and that their anions contain a complex oxalo-niobic acid radical.6... 

Rubidium Tantalate, 4Rb20.3Ta206.14H20, is obtained in transparent, colourless, monoclinic prisms by fusing tantalum pentoxide with rubidium carbonate and extracting the melt with water. It is isomorphous with the corresponding niobium salt and with 4 3 csesium tantalate. ... 

Metals high in the reactivity series have proved very difficult to isolate. It was not until more recent times, through Sir Humphry Davy s work on electrolysis, that potassium (1807), sodium (1807), calcium (1808) and magnesium (1808) were isolated. Aluminium, the most plentiful reactive metal in the Earth s crust, was not extracted from its ore until 1827, by Friedrich Wohler (p. 74), and the extremely reactive metal rubidium was not isolated until 1861 by Robert Bunsen and Gustav Kirchhoff. 

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