الفهرس 
Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
Summary and Conclusion Egyptian monazite sand, which is a phosphate of cerium and lanthanum, is an important source of the rare earth elements and thorium. It was found in black sands deposits at Rosetta area on the Mediterranean coast. Alkaline processing of Egyptian monazite black sand (97 % - 99 %) was developed earlier in Inshas Pilot Plant, NMA* for producing REEs and Th. Sulphuric acid was recently suggested for processing Egyptian crude monazite (35 % - 75 %) to produce rare earth elements. The present thesis deals with developing the sulphuric acid processing of monazite to isolate phosphoric acid, as a by-product, with the least contaminants. Production of thorium is, moreover, developed in the present work for peaceful industrial use. Production process is controlled through continuous chemical analysis of products in different stages besides qualifying the two out put products; monazite phosphoric acid and thorium oxide. The present thesis is composed of three chapters as follow: Chapter 1: Introduction and Literature Survey: It includes: Geological and mineralogical considerations of monazite beside chemical and radioanalytical identifications of uranium and thorium• Procedures for breaking down and processing of monazite. Besides, using precipitation techniques for isolating Th and REEs Spectrophotometric determination of thorium, rare earth elements, phosphorus and zirconium. Besides, laser-flourometric determination of uranium The use of statistical process control for assuring products qualities. Chapter 2: Materials and Methods: It includes:
• Specification of chemicals, reagents and instruments applied in the present work. Besides, preparation of the stock working solution Procedures used for processing monazite by conventional and partial processes for isolating high quality purified phosphoric acid and thorium. Besides, the applied analytical methods as a base for quality assurance of the out put products. Chapter 3: Results and Discussion: This chapter includes summary of the results obtained and divided into three main parts which are. Part I: It includes the conventional processing of monazite with sulphuric acid, whereby phosphoric acid (13 % P2O5) can be filtrated with high contaminations of RE2O3 (15.796 %), ThO2 (1.55 %) and U3O8 (0.27 %). Chemical analysis and statistical procedures are used for following out steps of work for estimating accuracy and precision of “out put” analytical data.Part II: It includes improving of the sulphuric acid monazite processing procedure for phosphoric acid production with the least contaminants. Attaining this purpose is carried out through varying; raw material / acid ratio, acid concentrations, dissolution temperatures, agitation times and sludge / hot water ratio. The ability of isolating phosphoric acid (14 % P2O5) with least contamination of RE2O3 (1.6 %), ThO2 (0.032 %) and U3O8 (0.14 %) is achieved by partial dissolution of monazite with concentrated H2SO4 by the ratio 1:3 (w/w) respectively, at 200 ?C with continuous stirring for 2 hours, leaching with hot water at 45 ?C and decanting the leachate solution. Assuring of monazite phosphoric acid product quality is carried out. Purification of the monazite phosphoric acid is carried out by firstly precipitation of REEs from it using oxalic acid by the ratio 1:4 (v/v) oxalic acid / monazite phosphoric acid containing REEs respectively. The obtained phosphoric acid is subjected to purification steps using butanol solvent extraction technique, and concentrated under pressure to get 31 % P2O5 in phosphoric acid free from Th, REEs and U with the recovery 83.9 %. Chemical analysis and statistical treatments are used for following out steps of work and for estimating accuracy and precision of the“out put” analytical data. Part III: It includes the processing of the remainder insoluble double sulphate / monazite material for thorium production. The remainder sludge, after partial dissolution and decantation of phosphoric acid, still containing unbreaked monazite and undissolved Th/REEs double sulphate salts. It is treated with H2SO4 by the ratio 1:4 (w/v) respectively, at 300 ?C with continuous stirring for 2 hours, leaching with iced water and filtered off. Thorium can be separated by precipitation with hexamine, carbonate and thiosulphate for producing white thorium oxide, ThO2 after ignition has purity 92.25 % and recovery 79.4 %. Chemical analysis and statistical treatments are used for following the steps of work and for estimating accuracy and precision of “out put” analytical data. The thesis is finished with flow sheet which shows the suggested steps for processing monazite and procedures for quality control using different chemical analysis.