Vanadium-uranium ore

Acid Leaching. DHect acid leaching for vanadium recovery is used mainly for vanadium—uranium ores and less extensively for processing spent catalyst, fly ash, and boiler residues. Although 20 in spent catalysts dissolves readily in acid solutions, the dissolution of vanadium from ores and... 

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... 

Vanadium Uranium ores and SR-NOX water Precipitation Oxide... 

The bulk of world vanadium production is derived as a by-product or coproduct ia processiag iron, titanium, and uranium ores, and, to a lesser extent, from phosphate, bauxite, and chromium ores and the ash, fume, or coke from burning or refining petroleum. Total world production of V20 was ca 131 X 10 lbs in 1996. 

In most uranium ores the element is present in several, usually many diverse minerals. Some of these dissolve in sulfuric acid solutions under mild conditions, while others may require more aggressive conditions. Thus, while it may be comfortable to recover 90-95% of the uranium present, it may be tough or impractical to win the balance amount of a few percent economically. Some of the most difficult uranium minerals to leach are those of the multiple oxide variety, most commonly brannerite and davidite. These usually have U(IV) as well as U(VI), together with a number of other elements such as titanium, iron, vanadium, thorium, and rare earths. To extract uranium from these sources is not as easy as other relatively simpler commonly occurring sources. 

Vanadium Raffinates from uranium ore extraction process Mineral leach liquors D2EHPA and TBP in kerosene High-molecular weight amines in kerosene... 

Figure 6.19 Extraction of vanadium by-products from uranium ores using alkaline hydrogen peroxide.

Fundamental studies have been reported using the cationic liquid ion exchanger di(2-ethylhexyl) phosphoric acid in the extraction of uranium from wet-process phosphoric acid (H34), yttrium from nitric acid solution (Hll), nickel and zinc from a waste phsophate solution (P9), samarium, neodymium, and cerium from their chloride solutions (12), aluminum, cobalt, chromium, copper, iron, nickel, molybdenum, selenium, thorium, titanium, yttrium, and zinc (Lll), and in the formation of iron and rare earth di(2-ethylhexyl) phosphoric acid polymers (H12). Other cationic liquid ion exchangers that have been used include naphthenic acid, an inexpensive carboxylic acid to separate copper from nickel (F4), di-alkyl phosphate to recover vanadium from carnotite type uranium ores (M42), and tributyl phosphate to separate rare earths (B24). 

Economic Considerations and the Classification of Ore Deposits The Example of Vanadium-Uranium... 

In the second process the alkaline solution is mixed with acid and the carbon dioxide liberated driven of by boiling. The resulting acidic solution is then neutralized with ammonia or magnesium oxide, whereupon uranium precipitates together with molybdenum and vanadium. The process is therefore only used if uranium ores have low concentrations of molybdenum and vanadium. 

Vanadium has an abundance in Nature of about 0.02%. It is widely spread but there are few concentrated deposits. Important minerals are patronite (a complex sulfide), vanadinite [Pb5(V04)3Cl], and carnotite [K(U02)V04.> fH20]. The last of these is more important as a uranium ore, but the vanadium is usually recovered as well. Vanadium also occurs widely in certain petroleums, notably those from Venezuela, and it can be isolated from them as oxovanadium(iv) porphyrins.1 V2Os is recovered from flue dusts after combustion. 

Total uranium can be analyzed by redox titration against acidified potassium permanganate, ceri-um(IV), or potassium dichromate. Uranium is reduced prior to the titration with zinc amalgam. Dichromate titrations are used to determine uranium concentrations in dissolved uranium metal, uranium ore, or yellow cake (UO3) samples. There are potential interferences from bismuth, manganese, platinum, silver, vanadium, and zirconium, which must therefore be removed prior to the titration. 

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