الفهرس 
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Abstract
This study conducted on the white silica sands samples from Wadi
Qena and Somr El-Qaa Formations in North Eastern Desert, between Wadi
Dakhl and the central part of Wadi Qena. The study aimed to evaluate the
quality of these sands and finds out its possible industrial applications;
Examine the best suited and cost-effective processing methods; Develop a
beneficiation plant for the total utilization of all size fractions and design
special flotation-attrition scrubbing machine for silica sands processing and
verify the possible paleodepositional environment, source and geotectonic
setting of these sands.
The study has been designed and carried out in two main stages.
The first stage is integrated evaluation and characterization of the
physical, the mineralogical and the geochemical properties. The second
stage is the beneficiation of the studied sands using screening, attrition
scrubbing and reverse flotation techniques.
Grain size analyses of representative samples showed that theaverage grain size parameters are as following; mean grain size for the
kaolinitic sandstones of Wadi Qena Formation is 2.33φ (Fine Sand),
sorting is 1.15φ (Poorly Sorted), skewness is 0.44 (Very Fine Skewed),
and kurtosis is 4.23 (Extremely Leptokurtic). The average mean grain
size for the silica sands of Somr El Qaa Formation is 1.791φ (Medium
Sand), sorting is 0.507φ (Moderately Well Sorted), skewness is -0.058
(Symmetrical) and kurtosis is 1.274 (Leptokurtic).
The Bivariate plot of standard deviation against mean size showed
that the sandstones of Somr El-Qaa Formation was mainly deposited in a
shallow agitated marine environment (beach) while the sandstones of
Wadi Qena Formation was mainly deposited in a fluvial environment.The morphological study results showed that the average circularity
and angularity of Wadi Qena Formation sand grains ranged from 0.72 to
about 0.81 (High Circularity) and from about 0.24 to 0.43 (Angular to
Sub-angular), Somr El-Qaa Formation sand grains ranged from about
0.70 to about 0.80 (High Circularity) and from about 0.38 to 0.54 (subrounded),
respectively. Generally the grain shape parameters are suitable
for the specifications of many industries, with limitation in roundness
parameter for hydraulic fracturing sands and filter media sands.
XRD study of the Wadi Qena Formation sandstone samples
indicated that the quartz and kaolin clay mineral were found as major
constituents. While the mineralogical investigation of the Somr El-Qaa
Formation sandstone samples indicated that the one and only major mineral constituent was quartz.The heavy minerals analysis results showed that the weight
percentage of the heavy minerals in the studied size fractions (500 or
600-90 μm) was found to be 0.036 % for the Somr El Qaa Formation
samples and 0.05 to 0.06 % for the Wadi Qena Formation samples. Nonopaque
minerals constitute the main bulk of the heavy mineral suite as
they reach in abundance more than 51 % in most samples, they
dominated by three major minerals (Tourmaline, Zircon and Rutile).
The petrographical study results showed that the sandstones of
Wadi Qena dominated by quartz wackes, while the sandstones of Somr
El-Qaa Formation dominated by quartz arenites. The detrital mode of
both deposits is characterized mainly by the removal of all mineral
except quartz and refractory accessory grains