Abstract: A process for the extraction of metals from an aqueous solution of metals in the form of their metal ions. The preparation and use of an efficient organic extractant and also the recovery from the organic extractant of the metal ions. A process for preparing an extractant solution where the extractant solution is a solution of a calcium ion or magnesium ion loaded extractant in a water-immiscible organic solvent, and where the extractant solution is suitable for extracting metal ions from an aqueous solution containing the metal ions, including mixing an aqueous solution of calcium ions or magnesium ions with a basic calcium salt or a basic magnesium salt and with a solution of an organic extractant in a water-immiscible organic solvent to form the extractant solution, and then separating the extractant solution from the aqueous solution.