Applications of solvent extraction operations and processes play one of the most important roles in Hydrometallurgy. Therefore, in this brief review, some general concepts for selected representative applications are discussed. Also, one particular entrainment problem solution is discussed in some more details. At first, the selected general concepts for metal production of copper and uranium from their ores are presented. Then after, the leaching-solvent extraction-electro winning process for copper is shown. Finally, the extraction of uranium from wet phosphoric acid is discussed.