Wyniki wyszukiwania - BazTech

1

Comparison of Jameson cell and jet diffuser flotation column

Bilir K., Ucar A., Sahbaz O., Gursoy H., Oteyaka B.

Physicochemical Problems of Mineral Processing

|

2018

|

Vol. 54, iss. 1

174--181

EN

A Jet Diffuser Flotation Column (JDFC) is a newly designed flotation device which resembles the Jameson cell (JFC) in terms of operational principles, but it has an important difference regarding to the structural characteristics in the downcomer. The main difference of JDFC is the diffuser type of downcomer which has been designed using the hydrodynamic consideration and fluid mechanics principles. The aim of the design was to increase the device efficiency for coarse particle flotation. Therefore, the turbulence occurring at the end of the downcomer was reduced, and the detachment probability of the coarse particle decreased. In addition, a homogenous and stable foam zone in the cell was obtained. According to the experimental results carried out in a pilot scale showed that not only higher flotation performance in comparison to the Jameson cell was obtained specifically for the coarse particles but also the quiescent froth layer was acquired under the given conditions. In these experiments, a vertical pipe of JDFC having an inlet diameter of 60 mm and outlet diameters of 115, 125 and 135 mm was used with the separation tank with the diameter of 390 mm. By using the data, the pilot scale JDFC with the 4100 mm vertical pipe integrated with the separation tank was produced, and the flotation tests were carried out by using a talc ore. Finally, the talc recovery of 90% was obtained using the JDFC for the particle size of 350 μm.

2

Effects of air-to-pulp ratio and bias factor on flotation of complex cu-zn sulphide ore in the Jameson cell

Gursoy Y. H., Oteyaka B.

Physicochemical Problems of Mineral Processing

|

2015

|

Vol. 51, iss. 2

511--519

EN

The air-to-pulp ratio and bias factor are important operating parameters in the Jameson flotation cell. These parameters have significant effect on micro-events taking place between particles and bubbles in flotation, and hence on flotation performance. In this study, the possibilities of obtaining a Cu-Zn rich bulk concentrate from complex sulphide ore from the Cayeli region (Turkey) were investigated using the lab-scale Jameson cell. The effect of air-to-pulp ratio and bias factor on flotation recovery were also studied. The ore has problematic flotation behaviour due to very fine liberation size and oxidation. The results showed that the Cu-Zn rich bulk concentrate can be obtained from the ore with satisfactory grade and recovery. It was determined that the air-to-pulp ratio and bias factor have significant effect on the flotation recovery. The optimum values of air-to-pulp ratio and bias factor in flotation of rather fine sized minerals were determined to be within the range of 1-1.5 and 0.70-0.95, respectively.

3

Recycling of colemanite tailings using the Jameson flotation technology

Ucar A., Sahbaz O., Kerenciler S., Oteyaka B.

Physicochemical Problems of Mineral Processing

|

2014

|

Vol. 50, iss. 2

645--655

EN

In this study, beneficiation of colemanite minerals from tailings of the Emet Boron Processing Plant using a laboratory scale Jameson flotation cell was investigated in detail. Effect of some working parameters of the Jameson cell such as jet length, plunging depth of downcomer, and bias factor was studied for the flotation performance of colemanite. The results showed that all parameters showed a significant effect on colemanite flotation using the Jameson cell which was the first time used in boron flotation with a negative bias factor. The results also indicated that a high recovery could be obtained with a worthy grade values by the negative bias factor. According to the results obtained at the bias factor of -0.3, jet length of 3 cm, and plunging depth of 20 cm, B2O3 content of the sample increased to approximately 46% from 36.8% with a recovery of 98.47%.

4

Determination of turbulence and upper size limit in Jameson flotation cell by the use of computational fluid dynamic modelling

Sahbaz O., Ercetin U., Oteyaka B.

Physicochemical Problems of Mineral Processing

|

2012

|

Vol. 48, iss. 2

533-544

EN

In the coarse particle flotation, turbulence which can be treated as energy dissipation rate, is one of the most significant parameters effecting the recovery and grade. Therefore, determination of energy dissipation rate is very beneficial for delineation of coarse particle flotation and determining the maximum floatable particle size in any cell. In this study, Computational Fluid Dynamic (CFD) modelling for the Jameson cell has been carried out to determine the high turbulent regions and the effect on the upper floatable size limit. The CFD modelling has been utilized for determining the flow characteristics and hydrodynamic behaviour of the Jameson flotation cell. In parallel with this purpose the turbulence map of the cell has been determined and energy dissipation rate determined by using the CFD modelling. According to the result acquired from the CFD modelling, there are two main turbulent regions which are mixing zone in the upper part of the downcomer and critical region at the separation tank. While the high turbulence at the mixing zone supplies fine bubbles and fast collection of particles, the turbulence at the separation tank causes the main detachment of the bubble-particle aggregate. Then, the increase in turbulence in the tank causes the decrease of the maximum floatable size of particles. In addition, the average energy dissipation rate in the critical region has been determined and used for estimation of the maximum floatable particle size in the Jameson cell. Moreover, the effect of hydrophobicity has been discussed.

5

Gas entrainment rate and flow characterization in downcomer of a Jameson cell

Tasdemir T., Tasdemir A., Oteyaka B.

Physicochemical Problems of Mineral Processing

|

2011

|

Vol. 47

61-78

EN

The Jameson cell which is a new type of gas-liquid contacting device and can be considered as a type of plunging jet column, has been in use worldwide for the separation of fine minerals, coal particles and wastewater treatment etc. Flow characteristics in the downcomer of a Jameson cell are very important since the hydrodynamics of the cell is largely depends on the flow conditions. The hydrodynamics influences flow regimes in the downcomer and hence the gas holdup and bubble diameter are strongly affected by flow conditions. Depending on the air entrainment rate entered to the system, different flow regimes are observed in the downcomer. Bubbly flow which is observed at less air quantities is desired instead of churn-turbulent flow where the gas entrainment rate increase. In this research, the effect of operating conditions including nozzle diameter, downcomer diameter, jet velocity and jet length on gas entrainment rate, Qg , was evaluated experimentally for an air-water system for the bubbly and churn-turbulent flow. Between these factors, downcomer diameter was found to have very little effect on gas entrainment rate while increasing values of other factors had an increasing effect on it. The results were evaluated by forward stepwise linear regression (MLR) and a piecewise regression with Quasi-Newton estimation of breakpoint (PLR) to estimate the flow conditions and gas entrainment rates. The model by PLR was useful to understand the boundary of the flow characteristics since the two equations were valid in a certain air entrainment ranges, i.e. different flow conditions. The model developed was successful to determine the transition region from bubbly flow to churn-turbulent flow. Experimental data were in good agreement with theoretically predicted value.