Vanadium, and uranium

Australian Vanadium—Uranium Ore. A calcareous camotite ore at YeeHrrie, AustraHa, is iU-suited for salt roasting and acid leaching. Dissolution of vanadium and uranium by leaching in sodium carbonate solution at elevated temperature and pressure has been tested on a pilot-plant scale... 

A mercury cathode finds widespread application for separations by constant current electrolysis. The most important use is the separation of the alkali and alkaline-earth metals, Al, Be, Mg, Ta, V, Zr, W, U, and the lanthanides from such elements as Fe, Cr, Ni, Co, Zn, Mo, Cd, Cu, Sn, Bi, Ag, Ge, Pd, Pt, Au, Rh, Ir, and Tl, which can, under suitable conditions, be deposited on a mercury cathode. The method is therefore of particular value for the determination of Al, etc., in steels and alloys it is also applied in the separation of iron from such elements as titanium, vanadium, and uranium. In an uncontrolled constant-current electrolysis in an acid medium the cathode potential is limited by the potential at which hydrogen ion is reduced the overpotential of hydrogen on mercury is high (about 0.8 volt), and consequently more metals are deposited from an acid solution at a mercury cathode than with a platinum cathode.10... 

In May, 1830, a careful comparison of vanadium and uranium was made in Berzelius laboratory. It was found that vanadium forms two series of compounds, the vanadic and the vanadous, but Berzelius and Sefstrom did not succeed in isolating the metal. 

Calcium serves as a reductant for such reactive metals as zirconium, thorium, vanadium, and uranium. In zirconium reduction, zirconium fluoride is reacted with culcium metal. The high heat of the reaction melts the zirconium. The zirconium ingot resulting is remelted undet vacuum for purilicatinn. Thorium and uranium oxides are reduced with an excess of calcium in reactors or trays under an atmosphere of argon. The resulting tnetals are leached with acetic acid tu remove the lime. 

Solutions of uranyl salts are not precipitated by the addition of cupferron, the ammonium salt of nitrosophenyl-hydroxylamine, but if first reduced by means of zinc, all the uranium may be precipitated in acid solution by means of this reagent. The precipitate is soluble in chloroform. This reaction affords a means of separating vanadium and uranium by successive precipitation. 

It should also be noted that the list of elements is not dogmatically invariant Lavoisier pointed out that classification as an element is always provisional tomorrow, an element may be found to be a mixture or a compound. These two possibilities were frequently realized during the last century the rare earths [2-4] slowly revealed the presence of 16 elements, and for many years VO and UO2 [characterized by Martin Heinrich Klaproth (1743-1817) in 1789] were considered elements because nearly all vanadium and uranium compounds contain constitutional oxygen. 

Carnotite is a potassium uranyl vanadate for which the formula K20 2U03 V206 8H20 is frequently given. The ore, however, varies materially from this composition. It contains 19 or 20 per cent V206 and is valuable for both vanadium and uranium, as well as radium. It occurs extensively in Paradox Valley, Colorado, and in Utah, South Australia, Portugal, etc. 

Suitable catalysts for oxidation (22) are oxides of cobalt, cerium, vanadium, and uranium. Catalysts for ester formation are oxides of lead, molybdenum, silicon, uranium, and cerium. The best flavors are produced by the use of oxides of lead, copper, nickel, molybdenum, cobalt, titanium, and silicon. 

Bloomfield, C., and Kelso, W. I. (1973). The mobilization and fixation of molybdenum, vanadium, and uranium by decomposing plant matter. 

Then a negative potential scan is applied, thereby minimizing the interference from inorganic substances that do not form an amalgam. So, in this case, the electrode processes involved include adsorptive collection, followed immediately by reduction and amalgamation, reoxidation step, and finally the repetition of the reduction of the adsorbed complex. This approach has been successfully used for the determination of antimony in the presence of iron, vanadium, and uranium, which is usually difficult to achieve, especially in the presence of high uranium concentration. 

It has recently been discovered that the roasting of carnotite ore at 850°C in the presence of a few per cent of calcium sulphate, prior to carbonate leaching, enhances both the vanadium and uranium extraction efficiencies. A convenient way of achieving the desired conditions is to blend the ore with another carnotite ore with a high natural calcium sulphate content, when available, rather than waste the beneficial effect of the latter by treating it alone. 

A series of processes have been patented for the separation of vanadium and uranium by anion-exchange from sodium carbonate solutions resulting from carbonate leaching of carnotite ore. None of them, however, are believed to be operated commercially. Three methods of operation are proposed with a strong base resin. These are (a) selective elution of uranium followed by elution of vanadium, (b) selective elution of vanadium followed... 

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