Sulfate uranyl

Uranium ores are leached with dilute sulfuric acid or an alkaline carbonate [3812-32-6] solution. Hexavalent uranium forms anionic complexes, such as uranyl sulfate [56959-61-6], U02(S0 3, which are more selectively adsorbed by strong base anion exchangers than are other anions in the leach Hquors. Sulfate complexes are eluted with an acidified NaCl or ammonium nitrate [6484-52-2], NH NO, solution. Carbonate complexes are eluted with a neutral brine solution. Uranium is precipitated from the eluent and shipped to other locations for enrichment. Columnar recovery systems were popular in South Africa and Canada. Continuous resin-in-pulp (RIP) systems gained popularity in the United States since they eliminated a difficult and cosdy ore particle/leach hquor separation step. 

The Los Alamos water boiler served as a prototype for the first university training reactor, started in September 1953 at North Carolina State College. The cylindrical reactor core used uranyl sulfate [1314-64-3] UO2SO4, and cooling water tubes wound inside the stainless steel container. A thick graphite reflector surrounded the core. 

The homogeneous reactor experiment-2 (HRE-2) was tested as a power-breeder in the late 1950s. The core contained highly enriched uranyl sulfate in heavy water and the reflector contained a slurry of thorium oxide [1314-20-1J, Th02, in D2O. The reactor thus produced fissile uranium-233 by absorption of neutrons in thorium-232 [7440-29-1J, the essentially stable single isotope of thorium. Local deposits of uranium caused reactivity excursions and intense sources of heat that melted holes in the container (18), and the project was terrninated. 

In 1896, Becquerel discovered that uranium was radioactive (3). Becquerel was studying the duorescence behavior of potassium uranyl sulfate, and observed that a photographic plate had been darkened by exposure to the uranyl salt. Further investigation showed that all uranium minerals and metallic uranium behaved in this same manner, suggesting that this new radioactivity was a property of uranium itself In 1934, Fermi bombarded uranium with neutrons to produce new radioactive elements (4). 

Chemical Designations - Synonyms Uranium sulfate Uranium sulfate trihydrate Uranyl sulfate trihydrate Chemical Formula U02S04 3H20. 

The incorporation of anions, as for example, S04 , CO2-, etc., makes leaching possible through the formation of stable uranyl (VI) oxyanions. In sulfate leaching, an observation of the potential-pH diagram for the uranium system reveals that uranium species in solution may be in the form of cations U02+, neutral species U02(S04)2 or anions U02(S04)4-. The oxidation of uraninite, U02, in acid solutions, transforming U(IV) to U(VI), yields soluble uranyl sulfate through the reaction as shown below ... 

Write formulas for each of the following compounds (a) ammonium cyanide, (ft) mercury I) nitrate, and (< ) uranyl sulfate. 

Aqueous uranyl sulfate system, 25 429 Aqueous varnish removal systems, in fine art examination/conservation, 11 413 Aqueous zinc chloride, as cellulose solvent, 11 272... 

Uranyl hydroxides, 25 430 Uranyl metaphosphates, 25 433 Uranyl nitrate, 25 428 Uranyl perchlorate crystals, 25 429 Uranyl sulfate system, 25 429 Urban air quality, 17 814—815 Urea(s), 8 206-207... 

Compound Name Chloroform Uranyl Acetate Uranyl Nitrate Uranyl Sulfate Uranyl Sulfate Urea... 

Uranyl ions form complexes in solutions with most anions. Uranyl sulfate and carbonate complexes are especially strong and are used in extracting uranium from its ores. Of great practical importance are the complexes of the uranyl ions with nitrate that are soluble in organic liquids such as alcohols, ethers, ketones, and esters. One of the most important of these reactions is that involving the extraction of uranyl nitrate into TBP (the Purex process) ... 

In the 1950s, uranyl sulfate was stripped from the strong-base resins with a concentrated solution of chloride or nitrate, these being the two most efficient anions in the above sequence. Uranium was recovered from the strip solution by precipitation of the diuranate species with ammonia ... 

On the modem plants employing the Bufflex flowsheet, uranyl sulfate is stripped from the resins with the bisulfate anion. The eluate contains about 1 M sulfuric acid since this is the optimum concentration for the subsequent solvent-extraction process at lower acid concentrations, the tertiary amine in solvent extraction is only partially ionized, which reduces its capacity for uranyl sulfate, whereas at higher acid concentrations the bisulfate anion begins to compete with the uranyl sulfate anion for tertiary amine functional groups. 

Table 7 Thermodynamic Data" relating to the Formation of Uranyl Sulfate Complexes77...

Later, Becquerel used an uranium salt, uranyl sulfate, K2(J02(S04)2- 2HzO, in his experiment. 

In 1896 Antoine Henri Becquerel was experimenting with uranium-containing crystals (potassium uranyl sulfate) when he discovered that they emitted some type of rays that were able to expose photographic film and even penetrate solid matter. Ernest Rutherford studied these rays and determined that at least three types were emitted from the uranium-containing material. He named them alpha rays, beta rays, and gamma rays. 

Cathodic Stripping Polarography. Application to Solutions of Uranyl Sulfate. Anal. Chem. 32, 621 (i960). 

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