Removal of Ca and Mg ions from model acidic leach solutions with polymeric resins

Within the scope of this thesis; it is aimed to remove Ca2+ and Mg2+ ions from acidic leaching solutions of aluminum containing ores with polymeric resins. In this context, different commercial polymeric resins were tested directly and also modified with EDTA, oleic acid, phosphoric acid and D2EHPA for the removal of Ca and Mg ions in model acidic solutions using Batch technique. As a result of the experimental studies, the adsorption capacities, Ca and Mg removal rates of Amberlite IR120, Amberlite CG50 and Dowex 50WX4 polymeric resins were found to be the highest after being modified with EDTA. Then, the resins were modified with different EDTA concentrations and the most suitable EDTA concentration was determined as 0.02 M EDTA. The resins before and after modification were characterized by SEM-EDX, FT-IR, zeta potential and hydrodynamic diameter analyses. Optimum conditions for adsorption were determined using batch technique. Ca adsorption on modified Dowex 50WX4 resin in 50 mL volume at pH 4 and 0.5% adsorbent amount in 50 ppm multiple ion environment at pH 4 and 120 min contact time was calculated as 94.52% and Mg adsorption was calculated as 92.45%. Ca adsorption on Amberlite IR120 resin modified in 25 mL volume with 25 ppm multiple ion medium at pH 4 and 0.5% adsorbent amount in 60 min contact time was calculated as 97.12% and Mg adsorption was calculated as 96.09%. In 50 mL volume, Ca adsorption on Amberlite CG50 resin modified with 25 ppm multiple ion medium at pH 4 and 0.25% adsorbent amount for 60 min contact time was 95.19% and Mg adsorption was 93.95%. Isotherm calculations were performed for Dowex 50WX4, Amberlite IR120 and Amberlite CG50 resins and it was observed that they were compatible with Freundlich, Langmuir and Langmuir isotherms, respectively. As a result of the kinetic calculations, the pseudo-second order rate kinetics for all three resins were found to be compatible. Flame Atomic Absorption Spectrophotometer (FAAS) was used to determine the Al, K, Ca and Mg ions remaining in the solution during the adsorption experiments. In order to test the reusability of the resins, desorption of ions adsorbed on the resins was studied. After determining the appropriate elution solution and concentration for desorption, repeatability was studied. It was seen that Dowex 50WX4 resin could be used three times, Amberlite IR120 and Amberlite CG50 resins could be used twice. The adsorption of ions by the mini columns was tested and the results showed that adsorption occurred at a high rate. The optimized conditions were tested in real leaching solutions and adsorption was found to be highly efficient.