Mineral Processing
N. Khorasanizadeh; M. Karamoozian; H. Nouri-Bidgoli
Abstract
The bubble diameter effect on the bubble rise velocity profile in a flotation column is studied by the two-phase computational fluid dynamics (CFD) method. The simulations are done in the ANSYS® Fluent® software using a two-phase volume of fluid model. The computational domain is a square cross-section ...
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The bubble diameter effect on the bubble rise velocity profile in a flotation column is studied by the two-phase computational fluid dynamics (CFD) method. The simulations are done in the ANSYS® Fluent® software using a two-phase volume of fluid model. The computational domain is a square cross-section column with a 10 cm width and a 100 cm height, in which air is interred as a single bubble from the lower part of the column by an internal sparger. An experimental test is also performed, the hydrodynamics parameters are recorded, and the simulated results are validated using the values obtained for the bubble rise velocity. The simulation results obtained indicate that CFD can predict the bubble rise velocity profile and its value in the flotation column with less than 5% difference in comparison with the experimental results. Then the simulations are repeated for the other initial bubble diameter in the bubbly flow regime in order to study the bubble diameter effect on the rise velocity profile. The results obtained demonstrate that the larger bubbles reach the maximum velocity faster than the small ones, while the value of maximum velocity decreases by an increase in the bubble diameter. These results can be used to improve the flotation efficiency.
Mineral Processing
M. R. Khani; M. Karamoozian
Abstract
In the present work, we investigated and optimized the digestion efficiency, A/S (Al2O3/SiO2 in red mud), and N/S (Na2O/SiO2 in red mud) of mixed bauxite in Iran Alumina Company using the Bayer process. Digestion experiments were carried out in an induction rotary autoclave on a mix of Jajarm, Yazd, ...
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In the present work, we investigated and optimized the digestion efficiency, A/S (Al2O3/SiO2 in red mud), and N/S (Na2O/SiO2 in red mud) of mixed bauxite in Iran Alumina Company using the Bayer process. Digestion experiments were carried out in an induction rotary autoclave on a mix of Jajarm, Yazd, Tash, and Shirin Cheshmeh bauxites. A 4-factor 3-level response surface methodology was applied for the design and analysis of the experiment with the optimization of Na2O concentration, digestion temperature, residence time, and amount of lime addition. Towquadratics and one linear model were derived for the prediction of digestion efficiency, and A/S and N/S responses. The results obtained showed that the optimum amounts for Na2O concentration, temperature, amount of lime addition and residence time were 180 g/L, 275°C, 7.73%, and 50 minutes, respectively, in which the digestion efficiency, A/S, and N/S reached 72.05%, 1.169, and 0.27, respectively. Validation experiment showed that the digestion efficiency, A/S, and N/S were 72.24%, 1.162, and 0.28% respectively, which meant a 2% increase in digestion efficiency and a 0.09 and 0.02 decrease in A/S and N/S, respectively, compared to the current operating condition.
Mineral Processing
S. Shahraki; M. Karamoozian; A. Azizi
Abstract
Sulfur is one of the most significant impurities in coal, which reduces the quality of coal and also results in environmental pollution. This work was aimed to investigate the removal of sulfur from coal by the leaching method employing parameters expected to affect the removal rate such as acid concentration ...
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Sulfur is one of the most significant impurities in coal, which reduces the quality of coal and also results in environmental pollution. This work was aimed to investigate the removal of sulfur from coal by the leaching method employing parameters expected to affect the removal rate such as acid concentration (10-30%), temperature (40-80 °C), and reaction time (40-100 min). A response surface methodology using Box-Behnken design was employed to maximize, model, and evaluate the factors affecting the desulfurization process. The results obtained indicated that the desulfurization value increased with increase in the acid concentration, temperature, and reaction time. A quadratic model with a high correlation coefficient (R2=0.98) is proposed and developed for the relationship between the removal value and the influential factors. The modeling results demonstrated that the significance degree of factors was in the order of acid concentration>temperature>reaction time. It was also found that the maximum desulfurization (about 87%) could be obtained under the optimal conditions of acid concentration=25%, temperature=80 °C, and leaching time=84 minutes.
Ali Entezari; Mohammad Karamoozian; M Eskandari Nasab
Abstract
The possibility of selective leaching process was investigated during molybdenite flue dust leaching to recover its rhenium content. The results show that addition of alcohols to water makes the medium less favorable for molybdenum transfer into aqueous phase. On the other hand, addition of small amounts ...
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The possibility of selective leaching process was investigated during molybdenite flue dust leaching to recover its rhenium content. The results show that addition of alcohols to water makes the medium less favorable for molybdenum transfer into aqueous phase. On the other hand, addition of small amounts of alcohols (5-15%) makes a noticeable separation of rhenium over molybdenum, but by increasing the alcohol content recovery of both metals decreases. More than 90% of Re transferred into leach solution but the corresponding amount for Mo was only about 0.5%.
