الفهرس 
Theoretical ConsiderationsOnly 14 pages are availabe for public view
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Abstract
1. Characterization of Wadii El-Nakhil’s Oil Shale showed that, it contains high amount of inorganic constituents. The sample contains 15.34% silica, 21% calcium oxide, 6.98% alumina and iron oxide, 3% P2O5 and 7.48% SO3. The loss on ignition was due to organic and carbonate content = 43%.
2. Thermogravimetric analysis showed that the different thermal degradation of oil shale is probably a result of drastic chemical degradation. The thermogram consists of two distinct regions; at low temperature (300-500C) and at high temperature (600-800C). The low temperature region corresponds to the hydro-carbons that evolve from the sample during the heating stage of pyrolysis, which amounted to 28%.
3. The XRD spectrum showed that the main inorganic associating minerals are quartz, siderite, calcite, kaolinite and apatite.
4. The FTIR spectrum showed that the sample is rich in carbon and oxygen. It contains high intensity of characteristic peaks and bands for OH, aliphatic CH, CH3, CH2, carboxyl and carbonyl groups. In addition an intense aromatic matrix was found due to high organic matter content.
5. Mineralogical analysis showed that the shale matrix is composed of alternating dark and light lamina. The thickness of the alternating lamina ranges between 10–50 µm. The light lamina is comprised of carbonate lamina. Carbonate also presents as planktonic foraminifera which were partially replaced or filled with silica. Other mineral associated with it are quartz, pyrite and phosphate as dispersed silt size particles. Quartz occurs as cavity filling of foraminifer’s chambers or dispersed within the matrix. Pyrite in oil shale occurs as finely dispersed opaque particles or in framboidal form. Phosphate represented by phosphatic bioclasts including bone and scale remains of vertebrates and fishes.
6. The maximum grinding to 50 µm was achieved at 90 min using 12 rods in 2:1 solid liquid ratio with 56% by weight.
7. The Bond grindability test for oil shale sample showed that the ore with a feed size (d80) 2600 µm will consume about 24.63 KW/t to be ground to a product of size (d80) 360 µm.
8. The zeta-potential of pure kerogen showed that the zero point of charge was 1.2.Thezeta-potential of treated kerogen with kerosene or pine oil as collectors used in this study was slightly increased. The zero point of charge is slightly increased from 1.2 to 1.3 and 1.4 for pine oil and kerosene, respectively.
9. The contact angle for pure kerogen was 93. Treating of kerogen with kerosene or pine oil as collectors increased to 136° and 113°, respectively.
10. The floatability of kerogen at various pH and in the presence of different collectors showed that the floatability of kerogen was significantly increased by increasing pH up to9. The maximum floatability was achieved at pH 9 - 10 for pine oil while the maximum floatability was achieved at pH 9.5 for kerosene.
11. Various oil shale beneficiating procedures have been proposed.
12. Enhanced gravity separation technique using Falcon Concentrator for ground oil shale (50 µm) showed that the most effective parameters were centrifugal force, water pressure and feed flow rate. Increasing the G-force up to 300 (80 Hz) increased the grade but with low recovery. The recovery was increased with increasing water pressure up to 5 psi. The best result of 50.1% kerogen with 82% recovery was achieved at frequency of 70 Hz (243 G-force), water pressure of 1 Psi and feed flow rate of 0.5 l/min from oil shale sample of 28%.
13. Denver flotation machine was used for flotation experiments. The possibility of oil shale cleaning by non-ionizing collectors was investigated using kerosene and pine oil which are the most commonly reagents used in oil shale flotation. The following parameters collector dose, collector type and pH were studied. A concentrate of 33.26% kerogen with 88% recovery was obtained by using the kerosene as a collector at pH 9. It may be due to the kerosene molecules more attached to the organic grains via hydrophobic bonding, increasing their hydrophobicity, than the negatively charged silicate particles. The Methyl Isobutyl Carbinol (MIBC) as a frother played a role in enhancing the selective recovery of kerogen. The recovery was increased to 65%and grade of kerogen to 37.6%.
14. The different doses of pine oil didn’t affect the recovery and grade of kerogen. Although the pine oil acting as a frother and collector but it is not effective in conventional flotation of oil shale. The best recovery was obtained in the alkaline pH ranges. Beyond pH 9, Recovery of kerogen was 88.5% with kerogen of 38%. Increasing of feed solid content from 5 to 20% decreases both recovery to 11% and the grade to 30.5% kerogen.
15. Upgrading of the ground oil shale (20 m) using column flotation showed that the pulp density has the significant impact on the recovery and grade.
16. Screening designs are used when numerous parameters would effect a particluar process such as oil shale flotation process. Reduced three-factor interactions (3 FI) two-level factorial experimental design was empolyed to evaluate the effects of the eight independent parameters.
17. The pulp density has a significant impact on the recovery and grade in presence of kerosene as a collector. The grade of kerogen was increased with increasing solid concentration from 5 to 15%. At higher flow rate of wash water (0.36 cm/s) the kerogen grade was increased from 47% to 57% while at lower level of wash water flow rate (0 cm/s) the grade was increased from 48% to 55%. The recovery was slightly increased from 47% to 51% while at higher level of wash water (0.36 cm/s) the recovery was decreased from 52% to 48%.
18. In case of pine oil as a collector, the grade of kerogen was increased with increasing solids concentration from 5 to 15 cm. At higher wash water flow rate (0.36 cm/s) the kerogen grade was sharply increased from 45% to 58% while at lower level of wash water flow rate (0 cm/s) the grade was increased from 47% to 53%.Therecovery was slightly decreased with increasing solid concentration. It decreased at lower wash water flow rate (0 cm/s) from 54% to 50% while at higher wash water flow rate (0.36 cm/s) the recovery was decreased from 58% to 53%.
19. Frother concentration was the other parameter having an effect on recovery. An increase in frother concentration resulted in an increase in recovery and grade. In case of kerosene as a collector, the grade of kerogen was decreased with increasing superficial feed flow rate from 0.07 to 0.49 cm/s. At higher frother concentration of 10 ppm, the kerogen grade was decreased from 57% to 46% while at frother concentration of 40 ppm, there is no significant change in kerogen grade ( 39%).The recovery was increased with increasing superficial feed flow rate from 0.07 to 0.49 cm/s at lower frother concentration from 42% to 51% while at higher frother concentration the recovery was decreased from 52% to 48%.
20. In case of pine oil as a collector, with increasing the superficial feed flow rate from 0.07 to 0.49 cm/s. At higher frother concentration the kerogen grade was decreased from 52% to 47% while at lower frother concentration the grade was slightly increased from 38% to 40%.Therecovery of kerogen was increased with increasing superficial feed flow rate from 48% to 58% while at higher frother concentration the recovery was increased from 58% to 67%.
21. The grade of kerogen was decreased with increasing froth depth from 10 to 40 cm. At higher superficial air flow velocity (1.5 cm/s), the kerogen grade was sharply decreased from 57% to 44%, while at lower superficial air flow velocity (0.5 cm/s), kerogen grade was decreased from 58% to 50%.
22. The recovery of kerogen was increased with increasing froth depth from 10 to 40 cm. At high superficial air flow velocity (1.5 cm/s), kerogen recovery was sharply increased from 59% to 80%, while at lower superficial air flow velocity (0.5 cm/s), the kerogen recovery was increased from 43% to 65%. On the other hand, increasing of superficial air flow velocity decreased the kerogen grade with increasing kerogen recovery. It was expected that an increase in froth height would allow for drainage of water and gangue particles and cause a decrease in both recovery, especially given their relatively high density, and grade.
23. For pine oil, the grade of kerogen was decreased with increasing froth depths from 10 to 40 cm. At the higher air flow rate (1.5 cm/s) the kerogen grade was sharply decreased from 55% to 37%, while at the lower rate (0.5 cm/s) the grade was reduced from 57% to 42%. The grade in the case of kerosene as a collector was less than that of the pine oil (from 45% to 37% at higher flow rate and from 50% to 42% at lower air flow rate).
24. The recovery of kerogen was increased with increasing froth depth from 10 to 40 cm. At the higher air flow velocity (1.5 cm/s) the kerogen recovery was increased from 67% to 75%, while at the lower air flow rate (0.5 cm/s) the recovery was increased from 49% to 59%.An increase in air flow rate has been shown to result in a decreased froth residence time of air and greater entrainment. It is not as straightforward to quantify as the change in froth height, since a change in air flow may result in a change in froth structure. An increase in frother dosage will result in an increase in water recovery and an increase material recovered by entrainment. There is a substantial interaction between frother and depressant with lower frother dosages required at lower depressant dosages.
25. There are many competing interactions occurring during flotation and it is important to take these interactive effects into account when optimizing a flotation circuit.
26. The grade of kerogen was increased with increasing collector dosage from 0.5 to 1.5 kg/t. At the higher solid concentration (% 15 solids) the kerogen grade was increased from 52% to 58%, while at low solid concentration (% 5 solids) the grade was increased but with lower values from 33% to 46%.The recovery was dropped also. The recovery of kerogen was decreased sharply with increasing collector dosage from 0.5 to 1.5 kg/t even at lower solids concentration (% 5 solids) from 65% to 47% and at higher solids concentration (% 15 solids) from 61% to 42%.
27. A significant interactive effect was observed of the collector dosage and the pulp density on the grade while there is no significant effect of the pulp density on the recovery. It is caused by the fact that the increase in the pulp density results in the growing number of particles in the pulp, and consequently in the growing resistance when the bubble-particle aggregates travel upwards to the froth. Under such conditions detachment of particles from the bubbles is easier.
28. The grade of kerogen was increased with increasing collector dosage from 0.5 to 1.5 kg/t. At the higher level of solid concentration (%15 solids) kerogen grade was increased from 55% to 58% while at lower solid concentration (% 5 solids) the grade was increased from 39% to 45%. The highest grade was achieved with higher solid concentration by using pine oil or kerosene as a collector.
29. The recovery was decreased sharply with increasing collector dosage from 0.5 to 1.5 kg/t %, at lower level of solid concentration (% 5 solids) from 71% to 55% while at higher level of solid concentration (% 15 solids) the recovery was decreased from 67% to 49%. The decrease in flotation recovery at the high collector dosage is probably because of overdosing the collector.
30. On the other hand, the lower grade and recovery for pine oil as compared with kerosene as a collector may be due to the wetting effect of kerogen during grinding to the associated gangue minerals which make them hydrophobic and reduce their flotation selectivity. It was confirmed by the higher contact angle of kerogen-kerosene particle of 136 as compared with kerogen-pine oil particle of 113.
31. The ramp report that summarizes the optimum reaction factors leading to a predicted maximum kerogen grade of 52.35% and kerogen recovery of 78.41%. The calculated optimum parameters were 15% solid concentration, 0 cm/s superficial wash water velocity, 0.49 cm/s feed superficial velocity, 40 ppm frother concentration, 40 cm froth depth, 0.67 cm/s superficial air velocity, 0.5 kg/ton collector dosage, and kerosene as a collector.
32. Two suggested flow sheets for upgrading Egyptian oil shale are presented as follows:The first flow sheet includes crushing, wet grinding to less than 50 musing rod mill followed by wet grinding to less than 25 musing attritor ball mill. It was upgraded by enhanced gravity separation using Falcon Concentrator. At the optimum operating parameters of Falcon Concentrator a concentrate of 51.26 % kerogen with 81.53 % recovery was achieved.
33. The second flow sheet includes crushing, wet grinding to less than 50 m using rods mill followed by wet grinding to less than 20 m using attritor ball mill. The ground oil shale was employed as a feed for column flotation. At the optimum operating parameters of column flotation a concentrate of 52.3 % kerogen with 78.4 % recovery was achieved.