Magnesium diuranate (MgU₂O₇) is a compound of

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

. 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 A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pu ...

. The solids slurry is then processed through a series of tanks, where

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...

, sodium chlorate, and

steam Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...

are used to extract the uranium from the solids slurry. The average

leaching Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). and may refer to: *Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amoun ...

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 , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...

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.

References

{{Magnesium compounds Magnesium compounds Uranates Nuclear materials