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The Egyptian black sand deposits, beach economic mineral concentrates and upgrading of low grade ilmenite concentrate
Prof. Mohamed Ismail Moustafa
Nuclear Materials Authority
The Egyptian black sand deposits are distributed along the northern coastal plain between Abu Qir to the west and Rafah to the east. These deposits are manily encountered in the beach sediments and the coastal sand dunes. The Egyptian black sand deposits contain strategic and economic heavy minerals which are needed for either nuclear industry or other metallurgical and engineering industries.
The essential economic minerals in these deposits are ilmenite, FeTiO3; magnetite,Fe3O4; garnet,(Fe,Mg,Mn,Ca)3Al2(SiO4)3; zircon, ZrSiO4; rutile, TiO2 and monazite (REEs- Ce,La,Nd,…..,Th)PO4. In addition ,some accessory minerals are also found: gold, Au; cassiterite, SnO2; xenotime, YPO4; thorite, ThSiO4; thorianite, ThO2; pitchblende, UO3; cinnabar HgS; chevkinite, REE4 Fe+² (Ti,Fe+³)2 Ti2Si4O22; copper; zinc; lead and platinum.
The average content of total economic minerals differs from place to other along the northern coast of Egypt. This content rarely exceeds 5% in the most upper meter of the beach deposits. Taking into consideration the first 20 meters of depth , it was concluded that the top meter includes 40-50% of the average total economic minerals content, the top 5 meters include 70-80% and the top 10 meters include 85-95% of the average total economic minerals content. Ilmenite is the most common economic mineral, it alone represents about 50% of the total economic minerals content, while monazite has the lowest content, it represents 0.01% in average. The coastal sand dunes may contain average total economic minerals content higher than that of the beach sediments.
In the surfacial naturally high concentrated black sand deposits, the average total economic minerals content may attains more than 90%. Such surfacial sediments are represented by zones of erosion due to action of marine currents and waves.
Using both of wet gravity concentration, low-high intensity magnetic separation and high-tension electrostatic separation techniques, each of the individual economic minerals can be obtained in a corresponding high- purity mineral concentrate with accepted grade and recovery. The physical and chemical specifications for most of the obtained Egyptian economic mineral concentrates are suitable for local and foreign markets.
During the last 10 years definite amounts of the individual economic mineral concentrates were produced from the Egyptian black sand deposits using a project constructed by Nuclear Materials Authority. The following amounts of economic mineral concentrates were produced: leucoxene, 18 ton; rutile, 100 ton; zircon, 1000 ton; magnetite, 2600 ton and ilmenite, 4000 ton. Two thirds the produced amount of ilmenite were imported to China and others.
Ilmenite is the main economic mineral in the Egyptian black sand deposits. It is characteristic by low content of TiO2 and high content of Cr2O3. The contents of these two oxides may affect negatively on the marketing of ilmenite concentrates. Several processes for ilmenite treatments were suggested to improve its marketable specifications. As for example smelting process to produce high titania rich slag and pig iron and acid chemical treatments to produce synthetic rutile or TiO2 pigment.
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