Magnesium diuranate
Encyclopedia
Magnesium diuranate is a compound of uranium
. It is known in the uranium refining industry as "MDU" and forms the major part of some yellowcake
mixtures. Yellowcakes are an intermediate product in the uranium refining process.
To produce this form of yellowcake, crushed ore is mixed with hot water to a 58% solids slurry
. The solids slurry is then processed through a series of tanks, where sulfuric acid
, sodium chlorate
, and steam
are used to extract the uranium from the solids slurry. The average leaching
efficiency for this process is 98.5%. The uranium-bearing solution is then decanted and directed to a solvent extraction (SX) process for further purification. In this extraction step, the dissolved uranium is transferred from the feed solution into the organic solvent. Next a stripping step recovers the uranium into a sodium chloride
aqueous phase after which the barren solvent is recycled. The average efficiency of the SX circuit is 99.9%. The high-grade “pregnant” strip solution from SX goes to the next stage where magnesia
slurry is added to precipitate magnesium diuranate. The yellow cake precipitate is then thickened, dried, re-crushed and packed into industry standard 220 litre steel drums for shipment to customers.
As with all yellowcake process the selection of this end product is dependent on the properties of the ore to be processed. The point of using magnesia is that you need an alkali and magnesia can be cheap.
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
. It is known in the uranium refining industry as "MDU" and forms the major part of some yellowcake
Yellowcake
Yellowcake is a kind of uranium concentrate powder obtained from leach solutions, in an intermediate step in the processing of uranium ores. Yellowcake concentrates are prepared by various extraction and refining methods, depending on the types of ores...
mixtures. Yellowcakes are an intermediate product in the uranium refining process.
To produce this form of yellowcake, crushed ore is mixed with hot water to a 58% solids slurry
Slurry
A slurry is, in general, a thick suspension of solids in a liquid.-Examples of slurries:Examples of slurries include:* Lahars* A mixture of water and cement to form concrete* A mixture of water, gelling agent, and oxidizers used as an explosive...
. The solids slurry is then processed through a series of tanks, where sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
, sodium chlorate
Sodium chlorate
Sodium chlorate is a chemical compound with the chemical formula . When pure, it is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 250 °C to release oxygen and leave sodium chloride...
, and steam
Steam
Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
are used to extract the uranium from the solids slurry. The average leaching
Leaching (chemical science)
Leaching is the process of extracting minerals from a solid by dissolving them in a liquid, either in nature or through an industrial process. In the chemical processing industry, leaching has a variety of commercial applications, including separation of metal from ore using acid, and sugar from...
efficiency for this process is 98.5%. The uranium-bearing solution is then decanted and directed to a solvent extraction (SX) process for further purification. In this extraction step, the dissolved uranium is transferred from the feed solution into the organic solvent. Next a stripping step recovers the uranium into a sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
aqueous phase after which the barren solvent is recycled. The average efficiency of the SX circuit is 99.9%. The high-grade “pregnant” strip solution from SX goes to the next stage where magnesia
Magnesium oxide
Magnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
slurry is added to precipitate magnesium diuranate. The yellow cake precipitate is then thickened, dried, re-crushed and packed into industry standard 220 litre steel drums for shipment to customers.
As with all yellowcake process the selection of this end product is dependent on the properties of the ore to be processed. The point of using magnesia is that you need an alkali and magnesia can be cheap.