September 2020

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Use of Site Blocking Agent for Removal of Silica from Egyptian Iron Ore through Bio-flocculation

K.A. Selim, N.A. Abdel-Khalek and El-Sayed R.E. Hassan

Abstract: This paper is devoted to study the different physico-chemical interrelations of the system iron oxide-quartz in presence of microorganisms. Growing, isolation and selecting of tailored microorganisms to selectively adsorb onto the mineral surfaces of iron oxide or quartz, to be used as the sole flocculating agent or as a surface modifier to enhance the selectivity of the separation process is also one of the main objectives of the present work. The presence of microorganisms enhanced the settling rate of both iron oxide particles but they caused a significant dispersion for the quartz particles. The microorganisms have hydrophobic nature over the entire range of pH (2.0 - 12). The presence of these microorganisms on the surface of minerals changes the zeta potential of mineral surface gradually to reach that of the microorganisms. However, addition of (2.0 X108 cells) microorganisms as the sole flocculating agent for the binary mixture of iron oxide and quartz in absence of dispersing agent at different pH values yielded products of ~ 94.5 - 97.1 % Fe2O3 and 4.37 – 6.4 % silica with recovery of 60.9 – 79.6 %. The best grade (97.1 % Fe2O3 and 4.37 % silica) is obtained at the acidic pH of 3.5. The selectivity can be greatly improved in presence of (6X10-5 M) SHMP, as a dispersing agent, where a product of better grade (of ~99.2 % Fe2O3 and 1.3 % silica) was obtained at the expense of recovery. The grade of the product can also be increased to 99.9 % Fe2O3 when the microorganisms was used as a surface modifier during the selective flocculation process while using 6X10-5 M SHMP and 80 ppm of PAM at pH range of 3.5 – 5.8. Applying the microorganisms (about 1.0 X 108 cells) for bio-flocculation of an iron ore sample, a product of high grade (95.81 % Fe2O3 and only ~ 2.0 % silica with a total recovery of 50.38 %) was obtained from a feed assaying about 55.77 % Fe2O3.

[ FULL TEXT PDF 1-11 ] DOI: 10.22587/ajbas.2020.14.9.1

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A Study on the Beneficiation of Low Grade Ilmenite Ore for Industrial Applications

El-Sayed R.E. Hassan, M.A. Youssef, M.A. Abdel-Khalek, K.A. Selim and N.A. Abdel-Khalek

Abstract: Ilmenite is a very important source for titanium. Egyptian ilmenite ore contains 26.20 % TiO2, 50.09 % Fe2O3 and 14.35 % SiO2. Ore contaminates of silica and iron oxides should be removed to achieve a suitable ilmenite grade. This study aims at upgrading Abu Ghouson ilmenite deposits at the Eastern Desert of Egypt. Beneficiation of fine low grade ilmenite ore was successfully performed using Falcon SB40 concentrator. Falcon SB40 was tested for different ilmenite size fractions. It is displayed that falcon separation efficiency increased with decreasing feed size as well as with narrow size fractions while falcon is limited to size fraction less than 25 micron. Results of ilmenite feed -80+25 micron showed that a concentrate of 40.60 % TiO2 with 86.00 % recovery and 2.43 % SiO2 was achieved. Applying magnetic separation on the falcon heavy fraction, a final concentrate with 46.31 % TiO2 and 1.78 % SiO2 was obtained. The produced ilmenite concentrate coincide the standard specifications required for different industrial applications.

[ FULL TEXT PDF 12-21 ] DOI: 10.22587/ajbas.2020.14.9.2

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Effects of Different Household Treatment Methods on Minimizing Pesticide Residue Levels in Apple and Strawberry Fruits

Sarah S. Aggad, Tolessa Deksissa and Thomas V. Fungwe

Abstract: Consumption of fruits with detectable pesticides residues is rising various human health concerns including endocrine disruption, cancer and Parkinson’s disease. The purpose of this study was to assess the effectiveness of different household processes in reducing pesticide residues from two different types of fruits: apple and strawberry. Samples were spiked with known concentrations of commonly used eight fungicides and insecticides including vinclozoline, metalaxyl, methiocarb, cyprodinil, thiabendazole, myclobutanil, bifenthrin, and fenpropathrin. In apple fruit samples, the effectiveness of soaking in tap water, and soaking in Zamzam water (alkaline water) were tested in reducing eight pesticides. For the strawberry samples, three household processes including soaking in tap water, tap water + baking soda, and tap water + lemon juice were tested in reducing bifenthrin insecticide. Samples were blended and extracted using QuEChER. The extracted and concentrated samples were finally analyzed using Gas Chromatography Mass Spectrophotometer (GC-MS). Different household processes were compared based on the processing factor. The results revealed that soaking in Zamzam water reduced more pesticide residues compared with tap water. In case of washing strawberry fruits, tap water were most effective in reducing bifenthrin by more than 50% as compared to tap water with baking soda or tap water with lemon juice. This findings confirm that washing of fruits can remove pesticide residues, but the effectiveness depends on the physicochemical properties of a pesticide compound and type of fruits.

[ FULL TEXT PDF 22-28 ] DOI: 10.22587/ajbas.2020.14.9.3

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