The Jameson Cell consistently produces fine bubbles and intense mixing between air and slurry. This means fast, efficient flotation. While the principle of using air bubbles to recover particles is the basis of the technology, it is the way air bubbles are generated and how the bubbles and particles interact that make Jameson Cells unique.
In the Jameson Cell, particle-bubble contact takes place in the downcomer. The tank's role is froth-pulp separation and may incorporate froth washing to assist in obtaining product grade. With no agitators, blowers or compressors Jameson Cell installation is simple and operation is extremely energy efficient. As the energy for flotation is delivered by a conventional pump power consumption is significantly lower than the equivalent mechanical or column flotation cell. Optimal Jameson Cell performance is maintained by delivering a constant volumetric flowrate of pulp to each downcomer. While operating plants experience fluctuating process flows, the Jameson Cell is equipped with a tailings recycle system that automatically compensates for feed variations. In addition to maintaining consistent and optimal downcomer operation, the tailings recycle improves metallurgical performance by giving particles multiple 'passes' through the downcomer contacting zone. The Jameson Cell's ability to provide better selectivity and to control entrainment means product grade is not affected.
The Downcomer is the heart of the Jameson Cell where intense contact between air bubbles and particles occurs. Feed is pumped into the downcomer through the slurry lens orifice creating a high-pressure jet. The jet of liquid shears and entrains air from the atmosphere. Removal of air inside the downcomer creates a vacuum, causing a liquid column to be drawn up inside the downcomer. The jet plunges into the liquid column where the kinetic energy of impact breaks the air into fine bubbles which collide with the particles. The very high interfacial surface area and intense mixing results in rapid particle attachment to the air bubbles, and high cell carrying capacities.
The Tank Pulp Zone is where mineral laden bubbles disengage from the pulp. The design velocities and operating density in this zone keep particles in suspension without the need for mechanical agitation. Due to the rapid kinetics and separate contact zone in the downcomer, the tank is not sized for residence time therefore tank volumes are much smaller than equivalent mechanical or column cells. Jameson Cells are contact dependent, not residence time dependent.
In the Tank Froth Zone the grade of the concentrate is controlled by froth drainage and froth washing. Cells are designed to ensure an efficient, quiescent zone that maximises froth recovery. Froth travel distance and concentrate lip loadings are integral to the tank design.
The downcomer is where bubble-particle collision, attachment and collection occur. The different hydrodynamic regions of the downcomer are the Free Jet, Induction Trumpet, Plunging Jet, Mixing Zone and Pipe Flow Zone.
Induction Trumpet: The Free Jet impinges on the slurry in the downcomer. The impact creates a depression on the liquid surface and results in air being channelled into the area at the base of the Free Jet.
Pipe Flow Zone: Beneath the Mixing Zone, a region of uniform multiphase flow exists. The downward liquid velocity counteracts the upward flow of mineral laden air bubbles. The air bubbles and particles pack together to form a downward moving expanded bubble-particle bed. The dense mixture of bubbles and pulp discharge at the base of the downcomer and enters the tank pulp zone where the mineral laden bubbles disengage from the pulp.
The Australian Coal Industry served as a rigorous testing ground for the Jameson Cell in the 1980s culminating in the first full scale Jameson Cell coal installation at Newlands in 1990. The Jameson Cell is now the industry standard with over 100 coal cells installed by 2010 in Australia alone.
In a Coal Handling and Preparation Plants (CHPP) gravity separation techniques are used to separate coal from ash. At fine particle sizes (below 500 m) gravity separation is inefficient and flotation is required. Early coal operations used conventional flotation technology however high throughputs and strict product ash specifications made these circuits complex and inefficient with inconsistent performance.
The Jameson Cell is now the industry standard with over 100 coal cells installed by 2010 in Australia alone. The fine bubble size, high intensity and froth washing ability offers major advantages over conventional cells for recovery of highly hydrophobic, fast floating coal fines. These advantages provide superior, more consistent flotation performance, lower ash concentrates and high recovery in a single stage of flotation. Coupled with high throughputs, small footprint, simple installation and high availability the Jameson Cell has set the standard for installations in the coal industry. The largest installation at Curragh (Australia) treats over 5 Mtpa of coal fines using only twelve cells. Jameson Cells are also installed in coal operations in Africa, North America, Asia and Europe. Their simple integration into modular plants has allowed the benefits of Jameson Cell Technology to be utilised in the recovery of coal fines from tailings dams.
The Jameson flotation cell was developed jointly by Mount Isa Mines Limited and Professor G.J. Jameson of the University of Newcastle. The cell has been used in a number of cleaning applications within Mount Isa Mines Limited, and other mines within Australia. In 1990 the cell was tested in a number of flotation plants treating a variety of ores around the world.
This paper describes testwork at two medium sized concentrators in Arizona and at the Kidd Creek Concentrator. In these cases Jameson Cell testwork involved treatment of zinc and copper in roughing and cleaning stages.
A performance optimization study has been conducted using a laboratory Jameson Flotation Cell, which resulted in the development of empirical models for four key response parameters, such as product ash content, product total sulfur content, combustible recovery and separation efficiency. The empirical models were utilized to identify an appropriate experimental region to achieve a target set of metallurgical performances from the treatment of a flotation feed sample. The separation performance obtained from the treatment of three additional coal samples used in this investigation indicate that a high positive bias factor of about 0.6, which translates to a wash water ratio of 2.5, is required to produce superior quality coal especially from the treatment of high ash coals. The separation performance obtained using the same orificedowncomer combination with various size separation chambers indicate that the diameter of the separation chamber of the Jameson Cell can be potentially reduced without affecting the separation performance. In other words, more number of downcomers can be used with the same size cell, which will significantly improve the throughput capacity of the Jameson flotation technology without sacrificing the separation performance.