الفهرس 
Introduction and literature surveyOnly 14 pages are availabe for public view
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Abstract
Chapter 1: Introduction and literature survey.
The introduction concerned with the existence of tungsten in nature and especially in Egypt in addition to its primary minerals such as wolframite. After that, separation techniques of tungsten were mentioned that include leaching and extraction processes. Different uses of tungsten were mentioned. Special attention was directed to the relationship between radiation and tungsten shields which is the main target for this thesis. This section also involves the classification of different types of radiation with focusing on gamma radiation and its interaction with matter. Requirements of shielding materials were discussed.
The literature survey concerned the alkaline leaching of W(VI) from wolframite mineral and the extraction of tungsten by different ion exchange resins. The usage of hybrid nanocomposites as shielding materials in addition to its uses in textile field were also surveyed.
Chapter 2: Experimental part.
The experimental part includes the material used in this dissertation in addition to the different chemicals and reagents used in digestion of wolframite concentrate, leaching and extraction of tungsten in addition to nanocomposite synthesis and application. It also contains the mineralogical and chemical specification of Abu Rushied mineralized quartz vein. The optimization of leaching and extraction steps were described followed by application on Abu Rushied tungsten concentrate. The procedures followed to synthesis different tungsten-based composites were also mentioned. How were the synthesized composites applied on textile lab coat pieces was also clarified. The apparatus and instruments used in characterization, specification and analysis of different products were also listed. The experimental evaluation procedures of attenuation properties of different products were mentioned confirmed by some theoretical evaluation programs like X-COM simulations and Geant4 Monte Carlo simulations. At the end, several shielding expressions, and terms in addition to their calculations and equations were clearly explained.
Chapter 3: Results and discussion.
A. Investigation of Abu Rushied mineralized concentrate.
First of all, Abu-Rushied mineralized concentrate was mineralogical investigated by EDX and XRD. It was found that the received concentrate mainly contains wolframite tungsten mineral (Fe,Mn)WO4, cassiterite SnO2 and quartz SiO2 minerals. Both qualitative analysis (EDX-XRD) and quantitative analysis (ICP_OES) emphasized the presence of tungsten as ferberite mineral in which Fe:Mn ≥ 4. The concentration of tungsten was 17.67% which reflects a purity of 29.15 ≈ 30%. Other associated impurities were silica, tin, iron, calcium, magnesium, and aluminum.
B. Leaching of Abu Rushied wolframite concentrate.
Different leaching parameters were studied to optimize the alkaline leaching of W(VI) present in the wolframite concentrate. The leaching agents (e.g. NaOH, KOH, NaHCO3, Na2CO3, Na2S, (NH4)2HPO4, and Na2HPO4), grain size (-50/+60 mesh size, (-300 to +250 μm) to -200/+230 mesh size (-75 to +63 μm)), reagent concentration (M: 1.250 to 5.625 mol L-1), S/L ratio (1 g/X mL, X= 3, 4, 5, 6 and 7 mL), leaching equilibration time (from 30 min to 180 min) and temperature (25–98 ±1 °C) are the parameters were studied. The results showed that the tungsten leaching efficiency is higher in case of using NaOH edging out of other reagents used. The optimum leaching conditions were: -200/+230 mesh size (-75 to +63 μm), 5 mol L-1 NaOH concentration, S/L ratio of 1/5, 120 min stirring time and 100-105 oC leaching temperature. These optimum conditions were applied on Abu Rushied wolframite concentrate to generate the loaded leach liquor of tungsten.
C. Solvent Extraction of W(VI) by Alamine 336.
D. The leach liquor has a high content of W(VI) that is difficult to apply the adsorption technique.
E. Thus, we had to apply the solvent extraction technique to extract the high and hug amount of
F. W(VI).
G. The leach liquor has a high content of W(VI) that is difficult to apply the adsorption technique.
H. Thus, we had to apply the solvent extraction technique to extract the high and hug amount of
I. W(VI).
J. The leach liquor has a high content of W(VI) that is difficult to apply the adsorption technique.
K. Thus, we had to apply the solvent extraction technique to extract the high and hug amount of
L. W(VI).
M. The leach liquor has a high content of W(VI) that is difficult to apply the adsorption technique.
N. Thus, we had to apply the solvent extraction technique to extract the high and hug amount of
O. W(VI).
We had to apply the solvent extraction technique to extract the most amount of W(VI). Based on references, extraction applied by alamine 336/kerosene/modifier. The extraction condition was set to organic/aqueous ratio (O/A) 1/1 and time of contact was 10 min at room temperature. It was sufficient to extract 92.18% of tungsten from organic phase. The scrubbing step was carried out by using water at O/A ratio 20/1 for 2 min at room temperature. Stripping step was carried out using 5% NH4OH at pH ≥ 8 at O/A ratio 1/1 for 10 min at room temperature. The final product was sodium tungstate.
D. Adsorption of W(VI) from raffinate by Ambersep 900 SO4 resin.
Different adsorption parameters were studied to optimize the W(VI) extraction conditions by Ambersep 900 SO4 resin. The pH influence (1-12), Adsorption equilibration time (from 0 min to 240 min), initial concentrations (50-400 mg L-1≈ 0.110-2.168 mmol L-1) and Temperature (25–55 ±1 °C). The optimum adsorption conditions were: pH0: 6, Temp: 300 K (≈ 25 °C), SD:1 g/L, Time: 2 h stirring, speed: 150 rpm. These optimum parameters were applied on Abu Rushied raffinate.
E. Preparation of some tungsten nanocomposites
from tungstate salt, different tungsten-based composites were synthesized such as Bi2WO6, PbWO4, and Pb0.82Bi0.12WO4/W0.5Pb0.5Bi12O20 through hydrothermal route to be used as protective barriers against gamma rays. Numerous techniques have been used for characterizing the structure and the composition of elaborate composites, including XRD, Raman analysis, density, and SEM-EDX analyses. The XRD results indicated that composite is a mixture of two compounds: one is lead-bismuth tungsten oxide (Pb0.82Bi0.12WO4) with 65% and the other is tungsten lead-bismuth oxide (W0.5Pb0.5Bi12O20) with 35%. The density of these samples has been estimated. Moreover, the gamma photons shielding ability for the prepared composites has been investigated. The gamma shielding parameters such as LAC, HVL, MFP, ER%, RPE%. were evaluated.
F. Application of hybrid nanocomposites on textile.
The previously prepared nanocomposites were involved in preparation of coating layer to cover a lab coat textile. A lab coat fabric pieces obtained from workers in nuclear materials authority were loaded by hybrid nanocomposite of PbWO4 NPs or Bi2WO6 NPs and chitosan by dipping method. The coating layer was characterized by TEM images. Fabric pieces were characterized by SEM-EDX analysis. Mechanical properties such as tensile strength, elongation and air permeability were also determined in addition to antibacterial properties. The attenuation of X-ray/gamma ray and neutron radiation were also evaluated. The X-ray/gamma shielding parameters were evaluated such as MAC, LAC, HVL, TVL, MFP, Zeff, Ne and RPE for fabricated materials. The neutron shielding parameters such as neutron removal cross section, neutron absorption cross section and neutron scattering cross section were also evaluated.