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Hydrometallurgical treatment of non-sulfide zinc ore for precipitation of zinc oxide nanoparticles

Abdel-Aal E.-S. A., Rashad M. M., El-Shazly A. N., Ibrahim I. A., El-Shahat M. F.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 2

729--737

EN

Acid leaching of Egyptian zinc ore from the Um Gheig area was carried out with sulfuric acid. This study determines the optimum conditions for dissolution of non-sulfide zinc ore. The optimum conditions are 25% -74m particle size, 45 °C temperature, 2 h leaching time, 1.1 stoichiometric molar ratio of H2SO4 to Zn, 1:3 solid/liquid ratio. The maximum filtration rate is 1.6 Mg Zn•m-2•day-1at pressure difference of 0.80 bar. The zinc recovery is about 90%. As the zinc ore contains zinc silicate, some additives were tested to enhance filtration and prevent formation of silica gel. To increase the added value of the product, zinc oxide was precipitated by a co-precipitation method in a nanosize powder with average particle size ~ 20 nm. Photocatalytic degradation of methylene blue dye under UV light using ZnO nanopowders produced at different conditions was investigated. Photocatalytic efficiency with methylene blue (MB) concentration was reduced as much as 85% in 240 min with the produced nanoparticles.

2

Enhancing filtration rate of new valley oxidized phosphate concentrate with additives

Abdel-Aal E.-S., Abdel Rahman E., Kandil A.-H.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

124--135

EN

Phosphoric acid is utilized for production of fertilizers. It is mainly produced by wet processes, in which phosphate concentrate, produce by several operations including crushing, scrubbing, classification, attritioning, and desliming, is leached with sulfuric acid with coproduction of calcium sulfate dihydrate (phosphogypsum). The New Valley oxidized phosphate concentrate was processed for phosphoric acid production by addition of certain additives to improve gypsum filtration through modifying its morphology and particle size distribution. The additives used were cetylpyridinium chloride (CPC) as a cationic surfactant, sodium dodecyl sulfate (SDS) as an anionic surfactant and sulfonic acid (SA). The applied dosages ranged from 0.25 to 2.5 kg additive/Mg P2O5 in the phosphate concentrate. The filtration rate of the New Valley oxidized phosphate concentrate is 3.6 Mg P2O5 /m2day without additives. The filtration rate was increased by 33% and 31% with 1 and 0.8 kg/Mg P2O5 doses of CPC surfactant and sulfonic acid (SA), respectively. On the other hand, the filtration rate was decreased by 33% with addition of 1 kg/Mg P2O5 dose of SDS. The aspect ratios of gypsum crystals were 6:1, 3:1, 3:1 and 12:1 without additive, with CPC, SA and SDS surfactant, respectively. Reaction efficiencies without and with 0.8 kg/Mg P2O5 of CPC, SA and SDS dose of additives were 95.0%, 97.9%, 97.9% and 94.7%, respectively. The P2O5 recoveries without and with 0.8 kg/Mg P2O5 of CPC, SA and SDS dose of additives were 92.6%, 95.5%, 95.8% and 90.8%, respectively.

3

Upgrading the effluent quality of an aerated lagoon with horizontal roughing filtration

Nabizadeh R., Naddafi K., Khazaei M., Fard R. F., Izanloo H., Yavari Z.

Environment Protection Engineering

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2015

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Vol. 41, nr 3

121--136

EN

Removal of suspended solids and microorganisms from an aerated lagoon effluent with a horizontal roughing filter (HRF) was investigated. The aerated lagoon receives Qom municipal wastewater. The HRF was operated at three filtration rates of 0.5, 1.0 and 1.5 m3/(m2·h) during four month operation period. The measured values of turbidity, TSS, COD, pH, temperature and flow rate of HRF at the former filtration rate were 79±12 NTU, 100±11 mg/dm3, 190±12 mg/dm3, 7±0.1 °C, 17±8 °C and 0.82 dm3/min, respectively. The differences between inlet and outlet values of pH and temperature were not significant (P > 0.05). Measures turbidity, TSS and COD in HRF final effluent were 15±13.7 NTU, 37±295 mg/dm3, 64±39.7 mg/dm3, respectively, which corresponds to 81.1%, 63% and 66.3% removal efficiencies, respectively. A decrease of removal efficiency was observed upon increasing filtration rates. The Spearman correlation coefficients between the head-loss and removal efficiencies ranged from 0.578 to 0.968 pointing to a direct relationship. Results of modeling approach revealed appropriate compliance between the values of the observed and predicted TSS for higher filtration rates.

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The effect of environmental factors on filtration and the oxygen consumption rate of the rotifer Brachionus plicatilis:n a primary exploration of red tide control

Kang K.H., Seon S.C., Brzozowska R., Lee J.Y.

Oceanological and Hydrobiological Studies

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2010

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Vol. 39, No.1

3-9

EN

To evaluate the potential to control red tides using the mass-cultured heterotrophic grazer, rotifer Brachionus plicatilis, the effects of environmental factors (water temperature and salinity) on physical activities (filtration and oxygen consumption rate) of B. plicatilis were estimated. Experiments were conducted at different water temperatures (15, 20, 25, 30 and 35°C) and salinities (20, 25, 30, 35 and 40 PSU), in 25 different combinations (5 temperatures × 5 salinities). Results showed that water temperature and salinity had significant effects on the filtration rate of B. plicatilis (F=41.66, P<0.05). The results of multiple regression analysis yielded the following functional dependence of filtration rate (F) on water temperature (T) and salinity (S): F=-1.658+0.917T+0.63S (R^2=0.769, P<0.001). The highest filtration rate (4.23 š0.74 μl rot-1 h-1) was obtained at 30°C and salinity 35 PSU, and the lowest one (0.869 š0.13 μl rot-1 h-1) was observed at 15°C and salinity 20 PSU. Both water temperature and salinity had significant effects on the oxygen consumption rate of B. plicatilis (F=34.08, P<0.05). The results of multiple regression analysis yielded the following functional dependence of oxygen consumption rate (O) on water temperature (T) and salinity (S): O=-3.133+0.165T+0.81S (R2=0.938, P<0.001). The highest oxygen consumption rate (5.38 š0.66 ng rot^-1 h-1) was observed at 35°C and salinity 40 PSU, and the lowest one (1.01 š0.15 μg rot^-1 h-1) was observed at 15°C and salinity 20 PSU. Results from this present study indicated that the filtration and oxygen consumption rate of the rotifer were significantly influenced by the water temperature and salinity. The utilization of rotifer for red tide control has to consider the influence of environmental factors.

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Dyskusja wpływu zawilgocenia gruntu na prędkość filtracji węglowodorów na podstawie wyników eksperymentalnych

Fąfara Z., Miska W.

Wiertnictwo, Nafta, Gaz

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2007

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T. 24, z. 1

193-203

PL

Przygotowując laboratoryjne stanowisko pomiarowe do analizy migracji węglowodorów w ośrodku gruntowym, w wyniku bezpośrednich badań eksperymentalnych określono głębokościowy profil zawilgocenia fizycznych modeli gruntu. Badając migrację wybranych ropopochodnych substancji zanieczyszczających na przygotowanym stanowisku, obliczono prędkości pionowej filtracji węglowodorów w gruncie. Stwierdzono jej silną zależność od głębokości. Na odcinku około 1 m wartość prędkości filtracji malała ponad dziesięciokrotnie. Celem niniejszych rozważań jest próba wyjaśnienia tego zjawiska. W drodze studiów literaturowych dokonano wyboru modelu matematycznego opisującego filtrację cieczy w zawilgoconym ośrodku gruntowym. Na jego podstawie próbowano wytłumaczyć zaobserwowaną rozbieżność danych eksperymentalnych.

EN

A depth profile of wetting of physical ground models was determined at a laboratory stand for analyzing migration of hydrocarbons in a ground medium. Analyzing the migration of oil product contaminants, the vertical filtration rate was established in the ground. A strong dependence on depth was found. The filtration value decreased over 10 times at a distance of about 1 m. The aim of the paper was explaining this phenomenon. A mathematical model describing fluid filtration in a wetted ground medium was selected on the basis of the literature study. On this basis the authors tried to explain the discrepancy of the experimental results.