الفهرس 
LITERATURE SURVEYOnly 14 pages are availabe for public view
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Abstract
The main objective of thesis is to develop selected process for separation of individual and groups of rare earths from the effluent solution produced after extraction of uranium and thorium on chemical precipitation method and ion exchange resins. The production of its highest possible purity and recovery percent after its separation, up-grading and purification was fulfilled through economical resins. After Egyptian beach black sand monazite mineral was digested with concentrated sulfuric acid and dissolved in ice water to its sulphate leach liqueur, thorium was precipitated by partially diluted ammonia solution at pH 1.3 in its pyrophosphate. The up-grading and purification of thorium in this concentrate from different media (nitric, hydrochloric and sulphate)was also studied through the selective precipitation PH. Up-scaling pilot experiment was applied utilizing the lab obtained conditions for separation, up-grading and purification of thorium from monazite mineral for pre-conceptual design unit of the whole process. Thorium analysis under the previous optimum applied conditions was 87.5 % purity with 94% recovery. After uranium separation from the leach liquors using anion exchange resin, the effluent solution was subjected to separate rare earths. The individual separation of the REEs from the monazite mineral was studied using cation exchange resin Dowex 50-X8 and citrate as an eluting agent. It was possible to attain highly pure (99.9%) Nd, (97%) Pr, and (95%) La with total percent recovery nearly ~ 50%. Upgrading of rare earths in this concentrate from chloride media was also studied through the prepared chitosanacryloyl thiourea derivative. The adsorption behavior of trivalent rare earth elements from an aqueous chloride medium on the prepared chitosanacryloyl thiourea derivative were studied using equilibrium batch technique. The optimum loading pH value was found to be 5.0 at temperature 298 K. Kinetics and isotherm experiments were carried out at the optimum pH. It was enough to reach the adsorption equilibrium at 4 hours and the maximum uptake capacity was (2.1 mmol g -1) at 25°C. Complexation, ion exchange and electrostatic interaction were all believed to play a role in lanthanum adsorption on Chitosan acryloylthiourea derivative. The equilibrium adsorption data were fitted to second-order kinetic equation. The Langmuir adsorption isotherm models were used for the description of the adsorption process.
Keywords:-
Monazite, REO, ion exchange separation, Thorium.