Jameson cell
The Jameson Cell is a high-intensity froth flotation cell that was invented by Laureate Professor Graeme Jameson of the University of Newcastle (Australia) and developed in conjunction with Mount Isa Mines Limited ("MIM", a subsidiary of MIM Holdings Limited and now part of the Glencore group of companies).
The slurry is introduced at the top of the downcomer as a jet that draws in air through a second pipe to form a stable two-phase mixture (see Figure 3).
[18] The target minerals, with their collector-coated surfaces, attach to the bubbles and this mixture travels down the downcomer, driven by hydrostatic forces,[19] before it is discharged into the tank portion of the Jameson Cell (see Figure 4).
[20] The Cell is operated by initially closing the air inlet at the top of the downcomer and feeding the flotation pulp in through the nozzle.
[4] The Jameson Cell grew out of a long-term research program aimed at improving the recovery of fine particles by flotation.
The work started at Imperial College London, and continued when Jameson moved in 1978 to the University of Newcastle, NSW, Australia, where he is Laureate Professor (2015).
The device needed to be simple to construct and operate, capable of running for long periods with minimal maintenance, and should be resistant to blockage by stray large particles in the feed.
Lewis and Davidson[24] had recently published a theory to predict the maximum size of bubbles in a well-characterised flow environment.
Jameson then looked for simple and practical ways of generating the required shear rates, and found inspiration in the kitchen sink.
He led a further plant trial with a small cell in the lead-zinc concentrator at Mt Isa Mines Ltd in Queensland, initially working alone.
In 1989 a worldwide exclusive license was negotiated between Tunra Ltd on behalf of the University of Newcastle, Jameson, and MIM Holdings Limited, for the use of the Cell for metallurgical purposes.
The commercial development of the Cell occurred indirectly as a result of problems being experienced in MIM's Mount Isa lead–zinc concentrator (sometimes referred to as a "mill" in the mining industry).
[30] Instead, he developed the concept of using a jet in a downcomer to create the bubbles and eliminate the need for a sparger in conventional flotation columns.
[30] The concept of the Cell followed when further investigations showed that most of the bubble–particle interactions were occurring in the downcomer, rendering unnecessary the collection zone of flotation columns.
[31][32] A pilot two tonne per hour (t/h) Jameson Cell with a 100 mm downcomer and using an orifice plate to create the jet was tested in MIM's lead–zinc concentrator.
[10] Subsequently, a full-scale plant was commissioned at Newlands in the 1988–89 financial year, with six rectangular Cells (1.5 m × 3.5 m) installed in a two-stage arrangement.
[1] The objective was to determine the Jameson Cell's performance in cleaning copper concentrate to improve its grade by removing gangue minerals, including pyrite, magnetite, hematite and quartz.
Following the test work, Peko Mines installed two full-scale, 1.4 m diameter Jameson Cells in the concentrator, each with three downcomers.
[37] In the late 1980s, MIM built an SX–EW plant at Mount Isa to recover copper leached from low grade ore stockpiled while mining its Black Rock open cut in the 1960s.
[7] The installation by Phelps Dodge (now Freeport-McMoRan) for electrolyte cleaning at its Morenci operation in Arizona was notable for having a large cell 6.5 m in diameter with 30 downcomers.
[6] Toward the end of the period, Cells were installed in coal preparation plants operated by the BHP Mitsubishi Alliance and by Peabody for fines recovery.
[30] The orifice plate used to generate the slurry jet was a high-wear item and its materials of construction were also a focus of the development effort.
[30] This interaction could reduce overall cell recovery by causing particles collected by bubbles in the downcomer to detach in the pulp tank.
[39] The motivation for installing Jameson Cells was, in part, to take advantage of their space-saving capabilities and to improve copper recovery at a minimum cost.
[39] The Cell circuit occupied 60% less floor area and achieved equivalent results to the mechanical banks with 40% of their residence time.
It included the following improvements: The earlier models of the Jameson Cell used orifice plates to generate the downcomer jet.
[3] The new slurry lens design had a smooth, shallow entry angle that created an optimum flow regime over the ceramic, reducing wear and extending its life.
[38] It has subsequently been applied at Israel Chemicals Limited's Dead Sea Works and by an unnamed producer in the Saskatchewan province of Canada.
[40] Phosphate processing operations that use flotation as the principal mechanism to concentrate the phosphate-bearing minerals usually discard particles smaller than 20 μm in diameter.
[12] In response, Legend developed a process based on using the Jameson Cell in a rougher-scavenger-cleaner configuration to recover at least 80% of the phosphate at a grade of at least 32% P2>O5 from a feed with a particle size distribution of up to 80% less than 20 μm.
