Uranous phosphates

The double salt, uranous chlorophosphate, UCl4.UH2(P04)2, separates in green crystals from a solution of uranous phosphate, UH2(P04)2.5H20, in concentrated hydrochloric acid. A chlorophosphate, of composition UCI4.3UO2.2P2O5, has also been prepared (see p. 328). 

Murdoch KM, Edelstein NM, Boatner LA, Abraham MM (1996) Excited state absorption and fluorescence line narrowing studies of inLuP04. J ChemPhys 105 2539-2546 Muto T, Meyrowitz R. Ponuner AM, Murano T (1959) Ningyoite, a new uranous phosphate mineral from Japan. Am Mineral 44 633-650... 

Muto T, Meyrowitz R, Ponuner AM, Murano T (1959) Ningyoite, a new uranous phosphate mineral from Japan. Am Mineral 44 633-650... 

Urano-hydroxyd, n. uranous hydroxide, ura-nium(IV) hydroxide, -reihe, /. uranous series, -salz, n. uranous salt, -uranat, n. uranous uranate, uranium(IV,VI) oxide, UaOa. -verbindung, /. uranous compound, Uran-oxyd, n. uranium oxide, specif, uranic oxide, uranium(VI) oxide, UOa. -ozydhydrat, n. uranium hydroxide, -oxydoxydul, n. = Uranoxyduloxyd. -oxydrot, n. uranium oxide red- -oxydul, n. uranous oxide, ura-nium(IV) oxide, UO2. -oxyduloxyd, n. uranoso-uranic oxide, uranium (I V,VT) oxide, UaOa. -oxydulsalz, n. uranous salt, uranium-(IV) salt, -pechblende, /., -pecherz, n. pitchblende, -phosphat, n, uranium phosphate. -rot, n. uranium red. -salz, n. uranium salt. 

All acid uranium phosphate, UH2(P04)2 or UO2.P2O5.H2O, is obtained as a gelatinous 23recipitate when ordinarj " sodium phosphate, or excess of sodium metaphosphate, is added to a solution of uranous chloride. It may be obtained in the crystalline form as UH2(P04)2.oH20. Aloy also describes a uranous chlorophosjihate of composition UH2(P04)2.UCl4 (see p. 295). 

Complex phosphates of uranium and the alkali or alkaline earth metals have been prepared by fusing an intimate mixture of the alkali phosphate with an excess of uranous oxide in a jdatinum Rose crucible through which carbon dioxide was passing. The fusion may be facilitated by the addition of a little alkali chloride. On slowly cooling the crucible, well-defined crystals of the double phosphate are formed. If the alkali metaphosphate is used, salts of the type RgU(P04)2 where R=K, Na R2=Ca, Sr, Ba, are obtained. 

Uranyl dihydro en phosphate, U02(H2P04)2.3H20, is obtained by concentrating a solution of uranic oxide in hot dilute phosphoric acid it separates in small yellow crystals. 

Uranous nitrate [U(N03)4] solution is used for the quantitative reduction of plutonium from loaded tributyl phosphate (TBP) phase [8]. Membrane cell technology was investigated for the production of 100% uranous nitrate solution [9], which is to be used in the partition cycle of the PUREX process in the fuel reprocessing plant. The membranes used hitherto have suffered from mechanical instability. A study was carried out at the BARC to obtain 100% uranous nitrate solution using a membrane-based electrolytic cell. The membrane used in this study was a thin polymer film reinforced with a Teflon fabric. The film was used as a separator between the anolyte and catholyte chambers, which are made of perfluorinated polymers, thus offering high thermal and chemical stability. 

A large number of inorganic layer crystals such as micas, sodium silicates, niobate, uranate, vanadate, titanate, zirconium phosphate, graphitic acids, crystalline silicic acids, vanadium oxyhydrate, calcium phosphoric acid esters, and titanium disulfide develop alkyl crystals between their rigid crystal layers by ion exchange with, for example, alkyl ammonium salts and by intercalation inorganic... 

Uran-plutonium extraction Uranium, plutonium Tributyl phosphate)... 

Uranium compounds include acetates, carbonates, halides, nitrates, oxalates, oxides, phosphates, and sulfates. In broad terms uranyl (hexavalent, VI) compounds, which exist primarily as the U02 complex ion, tend to be the most soluble. The uranous (tetravalent, IV) compounds, such as UF4, are less soluble. Uranium oxides are the least soluble [3]. 

An especially intriraing use of liquid-membrane technology, reported for the first time recently by Fox and Hayworth et al.," is the recovery of uranium from wet process phosphoric acid (WPPA). In the manufacture of fertilizer fiom phosphate rock, the acid is solubilized by treatment with sulfuric acid. In addition to HjP04, this crude leachate can contain up to 0.18 g/L of uranium. Under oxidizing conditions this occurs as the uranate ion, UO . Solvent extraction (SX) processes have been developed to recover die uranium values. One of the most common of these uses a mixture of di-(2-ethylhexyl) phosphoric acid (D2EHPA) and trioctylpbosphine oxide (TOPO) in kerosene solution. The chemistry of solvent extraction is as follows ... 

In sununaiy, the aqueous speciation of U in solutions that are believed to be representative of the relatively oxidizing and reducing groundwaters of the Tono region is dominated by U(OH)4(aq) under reducing conditions, and by the uranyl mono-, di- and tri-carbonato complexes, and (or) U02(0H)3, under relatively oxidizing conditions. Uranous fluoride or phosphate complexes, or their uranyl counterparts, are important in these respective solutions only if pH is less than 6 or 7. 

Volume IV Arsenates, Phosphates, Vanadates. (2000) (descriptions of 680 mineral species, including arsenates, phosphates, uranates, vanadates). 

Uranous complexes tend to be insoluble at low temperatures and at pH 4.5-7. At temperatures above 150°C uranous transport may become dominant. Depending on ligand concentrations, uranous fluoride, phosphate, sulphate and especially hydroxide compounds are important species under these conditions, but uranous carbonate complexes are not. Uranyl species are soluble over a wide range of conditions. In normal groundwater, at temperatures of 25°C, uranyl fluoride complexes are dominant at pH <4, uranyl phosphates at pH 4-7.5 and uranyl di- and tricarbonate complexes at pH >7.5. Uranyl silicate complexes are probably insignificant, and at temperatures near 100°C uranyl hydroxides predominate, whereas uranyl carbonate complexes dissociate. ... 

UDMH (Unsymmetrical dimethyl hydrazine) - 219, 303, 306, 309, 312, 315, 366 Ucon products 102, 156, 283, 366, 820 Udylite 61 - 845 Ultraformer feed - 215 Ultrasonic cleaning solutions - 884 Ultraviolet light - 94 Ultrawet detergent - 185, 215 Undecyl alcohol - 93, 226 Undecylenic acid - 629 Undertaker s restorative - 845 Union oils and fluids - 283, 820 Unvis hydraulic fluid - 366 Uran 156, 215 Uranium 732 Uranium chloride - 597, 740 Uranium extraction - 215 Uranium fluoride - 215 Uranium ore - 598, 719 Uranium SX units - 215 Uranium sulfate-sulfuric acid - 384 Uranyl ammonium phosphate - 740 Uranyl nitrate - 598, 740 Uranyl sulfate - 740... 

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