Uranium solvent extraction (SX) from aqueous acidic solutions is reviewed. First the uranium availability in earth as well as resources, mining and production reports is presented and followed by SX basic flowsheet and various important stages. Extraction, scrubbing, stripping and finally solvent equilibrium are presented in a flow-sheet form. The second half of the review discusses the various extractants used for uranium extraction and separation from acidic solutions. The extractants are divided in four types: 1) nitrogen-based extractants, 2) phosphorous-based extractants, 3) sulfur-based extractants, and 4) other extractants. Nitrogen-based extractants cover predominantly the amides and amines functional group containing extractants. The phosphorous-based extractants: tri-butyl-phosphate (TBP), di(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl (PC88A), tri-n-octyl-phosphine oxide (TOPO or Cyanex 923) and bis(2,4,4-trimethyl pentyl) phosphinic acid (Cyanex 272) are the most important members of this category. Sulfur-based extractants mainly sulfoxides and other sulfur-containing extractants are discussed. Heterocyclic compounds encompass isoxazolones, pyrazolones, crown ethers and other available extractants. A compact summary of the literature on uranium SX processes as well as extraction efficiencies is given in table form.

Ionic liquids, low temperature molten salts, have various advantages manifesting themselves as durable and environmentally friendly solvents. Their application is expanding into various fields including hydrometallurgy due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, and wide electrochemical potential window. This paper reviews previous literatures and our recent results adopting ionic liquids in extraction, synthesis and processing of metals with an emphasis on the electrolysis of active/light, rare earth, and platinum group metals. Because the research and development of ionic liquids in this area are still emerging, various, more fundamental approaches are expected to popularize ionic liquids in the metal manufacturing industry.