الفهرس 
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Abstract
This thesis represents geological, petrological, ore mineralogical and geochemical studies of the Egyptian ilmenite ores, represented by the Abu Ghalaga ilmenite ore deposits, and their associating gabbroic and granitic rocks. Additionally, the suitability of these ilmenite ores for production of high purity synthetic rutile nanoparticles, which have several industrial applications, is evaluated.
Fe-Ti oxides ores in Egypt are located in several localities in the Eastern Desert including Abu Dahr, Umm Effin, Hamra Dome and Abu Ghalaga area. Among these localities Abu Ghalaga area was selected in the present work as it contains the largest reserve of ilmenite in Egypt.
In the Abu Ghalaga area, the ilmenite ore is hosted by gabbroic rocks that are bordered from the western and south-eastern sides by trondhjemitic rocks. The ilmenite deposit and its associating gabbro are cut by a number of fine- grained granitic (aplitic) dykes.
Pertographically, the ilmenite-bearing gabbro of Abu Ghalaga can be classified into noritic, pyroxene-hornblende, and pegmatitic gabbros. Noritic gabbro is more fresh than the other varieties, and composed of plagioclase, orthopyroxene and clinopyroxene. The pyroxene-hornblende and the pegmatitic hornblende gabbros are characterized by the presence of brown hornblende, however, the latter has lower amounts of pyroxene, higher amount of plagioclase and hornblende and bigger size crystals. The fine-grained granitic dykes differ from the coarse-grained trondhjemitic rocks in the presence of K-feldspars (microcline) and the absence of biotite.
Geochemically, the Abu Ghalaga gabbroic and trondhjemitic rocks have a calc-alkaline to transitional affinity, while the aplitic rocks have a calc-alkaline affinity. The trondhjemitic rocks are proposed to be derived from depleted mantle source impregnated with LILE through subduction component in a subduction-related environment (island arc magma); while the aplitic rocks are proposed to be derived by partial melting of tonalitic source, shortly after collision (post-collision) of an intra-oceanic island arc with a continental margin. The Abu Ghalaga gabbroic rocks are believed to be derived from fractional crystallization of basaltic magma produced by partial melting of mantle source modified by subduction component at the end of the collision stage (late- to post-collision) of an intra-oceanic island arc with a continental margin.
The ilmenite ore deposits occur either as massive or disseminated ores confined to the southern portion of the Abu Ghalaga gabbro intrusion and concentrated in a zone trending NW-SE, conformable with the primary layering of the enclosing rocks. The ilmenite ore can be divided into two varieties namely; black ore situated in deep levels from the surface and red ore situated at or near from the surface. The black ore is called the fresh ore, while the red ore is called the oxidized one. Mineralogically, the ilmenite ores (black and red) are composed of ilmenite hosting exsolved hematite lamellae of variable sizes and shapes), gangue silicate minerals and some sulphides. However, the black ore differs from the red ore in the presence of larger amount of sulphide and silicate (plagioclase and pyroxene) minerals. Chemically, the red ilmenite ore is more enriched than the black one in the major oxides TiO2 and Fe2O3 (TiO2 = 41.36 and 37.36 wt %; Fe2O3 = 54.74 and 52.04 wt %, on average, respectively), however, both the black and red ores are generally enriched in V and in the HFSE (Nb, Zr, Hf & Ta).The chemical composition of the Egyptian ilmenite ore is similar to that of other ilmenite ores from several localities in the world but the Abu Ghalaga ilmenite ore is characterized by higher content of MgO and lower content of MnO. Based on field, petrographic and geochemical evidences, it is suggested that the origin of the Abu Ghalaga ilmenite ore was through late gravitational accumulation of Fe-Ti liquids, followed by squeezing of these liquids along the primary layering and fractures in the gabbroic host rocks forming the concordant and discordant dyke-like deposits.
The suitability of the Abu Ghalaga medium-grade ilmenite ore for production of high purity synthetic rutile nanoparticles was evaluated through a series of experiments using mechanical activation by ball milling, reduction by different reagents as carbon and hydrogen, hydrochloric acid leaching and calcination. The product of these experiments was synthetic rutile nanoparticles with purity higher than 95 %. Such high purity rutile nanoparticles product has a very wide field of industrial applications. The present study recommends further studies to evaluate the suitability of Egyptian ilmenite ores for production of other valuables synthetic materials, such as TiC, which have important industrial uses.