scholarly journals Role of Sparger Configuration in Determining Flotation Performance under Oscillatory Air Supply

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 638
Author(s):  
Yiming Ji ◽  
Ajuan Song ◽  
Chao Li ◽  
Yijun Cao
Keyword(s):  
Bubble Size ◽  
Plate Thickness ◽  
Nonlinear Relationship ◽  
Chamber Volume ◽  
Flotation Recovery ◽  
Air Supply ◽  
Flotation Performance ◽  
Orifice Size

Bubble size is crucial for determining flotation efficiency. Fine bubbles can be cost-effectively generated using a multi-orifice sparger with oscillatory air supply. Sparger configuration is defined by the orifice size, the plate thickness and the chamber volume. To date, the effect of sparger configuration on bubble size with oscillatory air supply is not clear yet. To facilitate the control of bubble size formed with oscillatory air supply, the present work investigated the dependence of bubble size on sparger configuration. It was found that bubble size was positively correlated with the chamber volume and the orifice size, while a nonlinear relationship was observed with the plate thickness. Besides, it was found that flotation recovery decreased over increasing bubble size when changing the sparger configuration. The results indicated that sparger configuration exhibited a significant effect on flotation performance via influencing bubble size when oscillatory air supply was applied.

scholarly journals Flotation of Carbonaceous Matter from a Double Refractory Gold Ore: The Effect of MIBC on Flotation Performance and Kinetics

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1021
Author(s):  
Sugyeong Lee ◽  
Charlotte E. Gibson ◽  
Ahmad Ghahreman
Keyword(s):  
Bubble Size ◽  
Gold Recovery ◽  
Carbonaceous Matter ◽  
Flotation Kinetics ◽  
Pressure Oxidation ◽  
Gold Ore ◽  
Refractory Gold ◽  
Flotation Performance ◽  
Thiosulfate Leaching

The use of alkaline pressure oxidation to pretreat refractory gold ore often results in insufficient gold recovery (<60%) in downstream thiosulfate leaching. To improve gold recovery, flotation was considered for the separation of carbonaceous matter (C-matter). In this study, the effect of MIBC on C-matter flotation was investigated to understand the role of the frother in bubble and froth formation and on flotation kinetics. MIBC dosages between 30 and 150 g/t were used in combination with 500 g/t of kerosene as a collector. The results showed that the recovery and selectivity of C-matter were improved with increasing MIBC dosages. Improved selectivity at higher MIBC dosages was attributed to faster C-matter recovery as bubble size decreased to the critical coalescence concentration (CCC) and to changes to the foam structure. Analysis of flotation kinetics showed that the flotation rate increased as the MIBC dosage increased due to the decreasing bubble size and the reduced induction time caused by the interaction between the collector and the frother. The results of this study explain the role of MIBC in C-matter flotation and can be used as a design basis for scavenger-cleaner flotation testing. Overall, the results show the potential for flotation as a means to improve gold recovery in thiosulfate leaching through the removal of C-matter.

scholarly journals Development of Bubble Characteristics on Chute Spillway Bottom

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1129
Author(s):  
Ruidi Bai ◽  
Chang Liu ◽  
Bingyang Feng ◽  
Shanjun Liu ◽  
Faxing Zhang
Keyword(s):  
Size Distribution ◽  
Bubble Size ◽  
Dissipation Rate ◽  
Bubble Diameter ◽  
Bubble Size Distribution ◽  
Impact Zone ◽  
Air Bubble ◽  
Air Supply ◽  
Bubble Characteristics ◽  
The Impact

Chute aerators introduce a large air discharge through air supply ducts to prevent cavitation erosion on spillways. There is not much information on the microcosmic air bubble characteristics near the chute bottom. This study was focused on examining the bottom air-water flow properties by performing a series of model tests that eliminated the upper aeration and illustrated the potential for bubble variation processes on the chute bottom. In comparison with the strong air detrainment in the impact zone, the bottom air bubble frequency decreased slightly. Observations showed that range of probability of the bubble chord length tended to decrease sharply in the impact zone and by a lesser extent in the equilibrium zone. A distinct mechanism to control the bubble size distribution, depending on bubble diameter, was proposed. For bubbles larger than about 1–2 mm, the bubble size distribution followed a—5/3 power-law scaling with diameter. Using the relationship between the local dissipation rate and bubble size, the bottom dissipation rate was found to increase along the chute bottom, and the corresponding Hinze scale showed a good agreement with the observations.

Experimental Study of Chamber Volume Effect on Bubble Formation From Orifice Plates Submerged in Water

2018 ◽  
Author(s):  
Omkar S. Gokhale ◽  
Milind A. Jog ◽  
Raj M. Manglik
Keyword(s):  
Experimental Study ◽  
Bubble Size ◽  
Bubble Formation ◽  
Orifice Plate ◽  
Orifice Diameter ◽  
Equilibrium Contact Angle ◽  
Growth Time ◽  
Size And Shape ◽  
Chamber Volume ◽  
Gas Chamber

Experimental study of air bubble formation from orifice plates submerged in water pools has been carried out. Air is forced through the orifice by supplying it to a chamber connected to the orifice plate. The chamber volume plays an important role in determining the bubble growth time as well as bubble size and shape at departure. The effect of chamber volume is generally correlated in term of a dimensionless parameter, capacitance number (Nc), which is proportional to the chamber volume and is inversely proportional to the square of the orifice diameter. To better understand and characterize this effect, an experimental study is performed using ten orifice plates of diameter ranging from 0.61 mm to 2.261 mm with six different chamber volumes between 12 cc and 59 cc with the corresponding capacitance numbers varying from 0.2 to 19. The shape and size of the bubble are captured using high speed videography. The orifice plate material is acrylic glass which has an equilibrium contact angle of 38° with pure water. It was observed that the value of critical capacitance number or Nc above which the bubble evolution is affected by the gas chamber volume, is around 0.85. The bubbles are more spherical in shape, and the growth time is significantly smaller. Also, at high capacitance number (Nc > 7), the air flow in the bubble is so high that the bubble departs with a sharp apex and has a large volume. Above Nc > 10, the chamber effects plateau and further increase in gas chamber volume does not alter bubble size and shape at departure.

scholarly journals Role of Steel Plate Thickness on the Residual Stress Formation and Cracking Behavior During Flame Cutting

2019 ◽  
Vol 50 (9) ◽  
pp. 4178-4192 ◽  
Author(s):  
Tuomas Jokiaho ◽  
Suvi Santa-aho ◽  
Pasi Peura ◽  
Minnamari Vippola
Keyword(s):  
Residual Stress ◽  
Steel Plate ◽  
Plate Thickness ◽  
Cracking Behavior ◽  
Stress Formation

Hip Joint Control of PGO for Paraplegics

2006 ◽  
Vol 326-328 ◽  
pp. 735-738 ◽  
Author(s):  
Sung Jae Kang ◽  
Jei Cheong Ryu ◽  
Gyoo Suk Kim ◽  
Mu Seong Mun
Keyword(s):  
Hip Joint ◽  
Joint Control ◽  
Hip Joints ◽  
Driving System ◽  
Air Supply ◽  
Air Muscle ◽  
The Right ◽  
And Control ◽  
Flexion And Extension

In this study, we developed a fuzzy-logic-controlled PGO (Power Gait Othosis) that controls the flexion and extension of each PGO joint using bio-signals and an FSR sensor. The PGO driving system works to couple the right and left sides of the orthosis by specially-designed hip joints and pelvic section. This driving system consists of the orthosis, sensor, and control system. An air supply system for muscle action is composed of an air compressor, 2-way solenoid valve (MAC, USA), accumulator and pressure sensor. The role of this system is to provide constant “air muscle” with compressed air at the hip joint. With the output signal of the EMG and foot sensors, air muscles assist the flexion of the hip joint during the PGO gait.

scholarly journals A Novel Method for Improving Low-Temperature Flotation Performance of Nonpolar Oil in the Molybdenite Flotation

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 609 ◽  
Author(s):  
Wan ◽  
Qu ◽  
Li ◽  
He ◽  
Bu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Surface Tension ◽  
Low Temperature ◽  
Interfacial Tension ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Maximum Surface ◽  
Flotation Recovery ◽  
Flotation Performance ◽  
The Magnetic Field

Nonpolar hydrocarbon oil (NHO) is one of the most extensively used collectors in the flotation of molybdenite due to its excellent selectivity. However, NHO has low sensibility at pulp temperature. At low temperatures (<283 K), although more kerosene is used, the recovery of molybdenite flotation is still lower than at room temperature. In this study, magnetizing treatment, which is an efficient, low-cost, innovative, and environmentally friendly emulsification method, was used to improve the flotation performance of NHO in low-temperature molybdenite flotation. The test results showed that, compared with unmagnetized kerosene (UMK), the optimum dosage of magnetized kerosene (MK) could be reduced by 11% at 298 K. At the same dosage of kerosene, the flotation recovery of MK was 3% higher than UMK at 278 K. The surface tension measurement results showed that the surface tension of MK rose periodically as the magnetic field intensity increased, and there was a maximum surface tension within each period. Further, the magnetic field intensity had the maximum flotation recovery of molybdenite at the maximum surface tension of MK. Combined with the analysis based on the Girifalco–Good theory and the static drop volume method of interfacial tension, the interfacial tension of kerosene–water was shown to decrease with the increase of the surface tension of kerosene. This finding indicates that the dispersibility of kerosene in pulp could be improved by reducing the size of oil droplets, thereby improving the molybdenite flotation recovery of kerosene at low-temperature pulp. It is helpful to improve the flotation recovery of molybdenite using NHO as a collector for low-temperature pulp (<283 K).

The role of Cu ion activation and surface oxidation for polymorphic pyrrhotite flotation performance in Strathcona Mill

2019 ◽  
Vol 134 ◽  
pp. 87-96 ◽  
Author(s):  
Chao Qi ◽  
Jing Liu ◽  
Jonathan Malainey ◽  
Lori J. Kormos ◽  
Julie Coffin ◽  
...  
Keyword(s):  
Surface Oxidation ◽  
Ion Activation ◽  
Flotation Performance
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