Solvent extraction of rubidium from leach liquor of central Iran metasomatic ores using macrocyclic crown ether ligands

Solvent extraction (SX) of rubidium (Rb) from leach liquor of central Iran metasomatic ores was studied with various macrocyclic crown ether ligands. Many crown ethers were used as extractants. Rubidium was quantitatively extracted from picrate media by dicyclobexano-18-crown-6 (DC18-C-6) in chloroform, and determined by flame emission spectrometry. Here, the factors affecting SX of Rb from synthetic solutions of rubidium (containing 100 mg L-1 Rb) in sulfuric acid medium were identified. 0.01 mol L-1 DC18C6 in chloroform, 0.01 mol L-1 picric acid in aqueous phase, aqueous to organic (A/O) ratio of 1, pH 5.5 and mixing time of 15 min are the optimum values for affective factors. The precipitation with sodium hydroxide was conducted to remove the leaching impurities such as Fe, Mg, Al. Complete extraction of Rb from aqueous solution and almost complete extraction of Rb (81%) from leaching filtrate containing 0.01 mol L-1 picric acid was performed using 0.01 mol L-1 DC18C6 in chloroform. The Rb complete strippings, was obtained with 4 mol L-1 and 5 mol L-1 hydrochloric and nitric acids, respectively, ‌with A/O ratio of 1:1.