الفهرس 
General Introduction and Literature ReviewsOnly 14 pages are availabe for public view
 |  | from | 110 |  |  |
| | | from | 110 | | |
Abstract
The present thesis is mainly oriented towards the development of a simple, rapid, accurate and non-expensive method for the determination of Samarium, Europium and Gadolinium in concentrate rare earth oxide without separation. The developed method depends on the derivative spectrophotometric determination by fourth order derivative.
The thesis comprises actually three chapters and a brief summary of each of which presented in the following paragraphs.
Chapter I includes an introduction on the history rare earth elements, its abundance on the earth’s crust, the main physical and chemical properties, the toxicity, and the literature review of the analytical methods by different instrumental and modern techniques.
Chapter II includes the experimental part concerning the materials used, the preparation of various stock and standard solutions as well as all the instruments which were used.
Chapter III involves all the obtained results and discussion concerning the development and optimization of the derivative spectrophotometric method for the determination of samarium, europium and gadolinium using chrome azurol S dye. For this purpose, a systematic presentation of all the studied relevant factors controlling the optimization of the method is undertaken. These are summarized in the following points:
1- Selection of the type of derivative for the spectrophotometric determination of complexes was fourth order derivative.
2- Selection of the suitable pH for the spectrophotometric determination of complexes was 7.5.
3- Effect of surfactant concentration on the absorbance of complexes was 0.5x10-3 M.
4- Effect of chrome azurol S dye concentration on the absorbance of complexes was 1x10-3 M.
5- Effect of duration time on the stability of complexes and observed that the best measure after 10 minutes and remain constant for 30 minutes.
6- The molecular structure of the formed complex was determined by the continuous variation method. The obtained results indicated that the molar ratio between metal and dye was found to be 1:1.
7- The studied complex obeyed Beer’s law up to 12 ppm.
In the last part of this chapter of the thesis essentially concerned with application studies. Thus, the first part included the location of the studied sample. The latter study included the recommended procedure for samarium, europium and gadolinium determination. The studied sample has been analyzed by using modern analytical technique; ICP– OES. The starting material of this work is Egyptian monazite upgraded to about 97 % mineralogical grade. It was obtained from black sands deposited at Rosetta area on Mediterranean coast. Monazite is resulted as a byproduct during the recovery of the economic heavy minerals. The mineral monazite is composed of rare earth phosphates along with thorium and uranium. It contains55-60% rare earth oxides. The comparison of the obtained data showed a sufficiently good agreement with those of ICP –OES. Also, statistical calculation of the obtained results were found satisfactory in a manner to prove that, the developed method is accurate, sensitive, reproducible and non-expensive.
from this work we can conclude that, the determination of Samarium, Europium and Gadolinium in concentrate rare earth oxide without separation. The developed method depends on the derivative spectrophotometric determination by fourth order derivative. The developed method is simple, precise, selective and accurate. Also the reagents involved are readily available and the analysis can be performed within a short period of time.