The Jameson Cell is a high-intensity froth flotation cell that was invented by Laureate Professor Graeme Jameson of the University of Newcastle and developed in conjunction with Mount Isa Mines (MIM), a subsidiary of MIM Holdings and now part of Glencore.G J Jameson, G Harbort and N Riches, "The development and application of the Jameson Cell," in: Fourth Mill Operators' Conference, Burnie, Tasmania, 10–14 March 1991 (The Australasian Institute of Mining and Metallurgy: Melbourne, 1991), 45–50.
The high intensity of the Jameson Cell means that it is much shorter than conventional column flotation cells (see Figure 1), and it does not require air compressors to aerate the suspension of ground ore particles and water (known as a slurry or pulp) in the flotation cell.G J Jameson, "Flotation cell development," in: The AusIMM Annual Conference, Broken Hill, New South Wales, 17–21 May 1992 (The Australasian Institute of Mining and Metallurgy: Melbourne, 1992), 25–31. The lack of a requirement for compressed air and the lack of moving parts means that power consumption is less than for the equivalent mechanical or conventional column flotation cell.M F Young, K E Barnes, G S Anderson and J D Pease, "Jameson Cell: the 'comeback' in base metals applications using improved design and flow sheets," in: Proceedings of the 38th Annual Canadian Mineral Processors Conference, Ottawa, Ontario, 17–19 January 2006, (Canadian Institute of Mining, Metallurgy and Petroleum), 311–332. Accessed 23 May 2013.
In contrast to most types of flotation cell, the Cell introduces the feed and the air to the Cell in a combined stream via one or more cylindrical columns referred to as "downcomers". Other types of flotation cell typically introduce the feed and the air separately to the cell.
The Cell produces fast mineral flotation rates, especially for very fine mineral particles. It produces high concentrate grades from fast floating liberated particles K E Barns, P J Colbert and P D Munro, "Designing the optimal flotation circuit – the Prominent Hill case," in: Tenth Mill Operators' Conference, Adelaide, South Australia, 12–14 October 2009 (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 173–182. and is able to do this from a single stage of flotation. The high carrying capacity of the Jameson Cell is particularly beneficial when high yields (mass pulls) are required, such as in recleaning in metals flotation and in the flotation of metallurgical coal, where yields can exceed 80%.R Araya, L Huynh, M Young and K Arburo, "Solving challenges in copper cleaning circuits with the Jameson Cell," to be presented at: Procemin 2013, Santiago, Chile, 15–18 October 2013.
The Cell was initially developed as a lower-cost alternative to conventional column flotation cells for recovering fine particles, and was first used in the Mount Isa lead–zinc concentrator in 1988.D Readett and B Clayton, "Cleaning hydrometallurgical liquor using Jameson Cells," in: Flotation Plants – Are They Optimized? Ed. Deepak Malhotra (Society of Mining, Metallurgy and Exploration: Littleton, Colorado, 1993), 164–170. . Since then, use of the technology has spread to include coal flotation, base and precious metal flotation, potash flotation, oil sands flotation, molybdenum flotation, graphite flotation and cleaning solvent extraction liquors.Xstrata Technology, "Jameson Cell installations," Accessed 29 May 2013. Xstrata Technology, Glencore Xstrata's technology marketing arm, listed 328 Jameson Cell installations in May 2013. Cells have been installed by 94 companies in 27 countries. Today, the technology is the standard in the Australian Coal IndustryB A Firth, "Australian coal flotation practice," in: Advances in Flotation Technology (The Society of Mining, Metallurgy and Exploration: Littelton, Colorado, 1999), 289–307. . where well over one hundred Cells have been installed to recover coal fines.Xstrata Technology, "Jameson Cell Applications." Accessed 1 July 2013.D Osborne, L Huynh, I Kohli, M Young and F Mercuri, "Two decades of Jameson Cell installations in coal," to be presented at The 17th International Coal Preparation Congress, Istanbul, 1–6 October 2013. It is mainly used in metals applications to solve final grade and capacity issues from conventional cell cleaner circuits. It has found a niche in transforming traditional circuit designs where its inclusion allows cleaner circuits to be designed with fewer cells in a smaller footprint, while achieving cleaner and/or higher grade concentrates. It has also made possible the recovery of previously discarded fine materials, such as coalR Q Honaker, A Patwardhan, M K Mohanty and K U Bhaskar, "Fine coal cleaning using Jameson Cells: the North American experience," in: Advances in Flotation Technology (The Society of Mining, Metallurgy and Exploration: Littelton, Colorado, 1999), 331–341. . and phosphate fines,A J Teague and M C Lollback, "The beneficiation of ultrafine phosphate," Minerals Engineering, 27–28, (2012), 52–59. thereby increasing the efficiency and extending the life of the world's non-renewable natural resources.
Operating principles
Froth flotation is achieved by mixing chemicals known as collectors with the ore slurry. The collectors adsorb onto the surfaces of the particles of select minerals (usually the valuable mineral that is targeted for concentration), making these minerals hydrophobic. Air is passed through the slurry in a tank known as a flotation cell. The air is broken into tiny bubbles by various mechanisms (depending on the design of the flotation cell), and the now-hydrophobic minerals attach to the bubbles, rising with them to the surface of the flotation cell, where they form a froth. The froth flows over the top edge (or "lip") of the flotation cell and forms the flotation concentrate. Ideally, none of the unwanted mineral particles float, and they remain behind as the flotation tailings.
However, the selectivity of the collection mechanism is not perfect. Some unwanted ("gangue") minerals are also carried into the froth, largely by entrainment with the water rising with the bubbles. This is particularly the case for particles less than 10 μm in size.N W Johnson and P D Munro, "Overview of flotation technology and plant practice for complex sulphide [sic] ores," in: Mineral Processing Plant Design, Practice and Control, Eds A L Mular, D N Halbe and D J Barratt (Society for Mining, Metallurgy and Exploration: Littleton, Colorado, 2002), 1097–1123. Some of the gangue particles follow the water between the bubbles as it drains back to the underlying pulp. This process can be assisted by the application of sufficient "wash water" to the froth to displace the water entrained with the bubbles and the fine gangue particles brought with them. Column flotation cells, invented in Canada by Boutin and Tremblay in 1961,B V Clingan and D R McGregor, "Column flotation experience at Magma Copper Company, with related experience of other mineral processors," presented at the SME Annual Meeting, Denver, Colorado, 24–27 February 1987. Preprint 87-91. grew increasingly popular in the 1980s and 1990s as a way of reducing entrainment of fine gangue particles during "cleaning" of flotation concentrates.G S Lane and R C Dunne, "Column flotation – an Australian perspective," in: The AusIMM Kalgoorlie Branch, Equipment in the Minerals Industry: Exploration, Mining and Processing Conference, Kalgoorlie, Western Australia, October 1987 (The Australasian Institute of Mining and Metallurgy: Melbourne, 1987), 81–93. With heights usually between 6 and 14 meters,G Dobby, "Column Flotation," in: Mineral Processing Plant Design, Practice and Control, Eds A L Mular, D N Halbe and D J Barratt (Society for Mining, Metallurgy and Exploration: Littleton, Colorado, 2002), 1239–1252. they could have froth depths up to 2 m, providing more residence time than conventional cells and more stable froth surfaces that enable better froth washing.
Froth flotation efficiency is determined by a series of probabilities: those of particle–bubble contact, particle–bubble attachment, transport between the pulp and the froth, and froth collection into the product launder.B W Atkinson, C J Conway and G J Jameson, "Fundamentals of Jameson Cell operation including size–yield response," in: Sixth Australian Coal Preparation Conference, Mackay, Queensland, 6–9 September 1993 (The Australasian Institute of Mining and Metallurgy: Melbourne, 1993).
In a conventional mechanically agitated cell, the void fraction is low (5–10%) and the bubble size is large (2–3 mm), which results in a low interfacial area with a low probability of particle–bubble contact. In a conventional flotation column, the void fraction is similarly low, and so the probability of particle–bubble contact is increased by increasing the height of the column to provide greater residence time.
Traditionally, the ore slurry and the air are introduced separately to the flotation cell (see Figure 2). The Jameson Cell differs from this traditional approach by mixing the slurry with the air in the downcomers.
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). The plunging slurry jet shears and then entrains the air.G Harbort, J Cowburn and E V Manlapig, "Recovery interactions between the froth zone, pulp zone and downcomer within a Jameson Cell," in: 10th Australian Coal Preparation Conference, Pokolbin, New South Wales, 17–21 October 2004 (The Australasian Institute of Mining and Metallurgy: Melbourne, 2004). Accessed: 23 May 2013. The target minerals, with their collector-coated surfaces, attach to the bubbles and this mixture travels down the downcomer, driven by hydrostatic forces,G M Evans, B W Atkinson and G J Jameson, "The Jameson Cell," In: Flotation Science and Engineering, Ed. K A Matis (Marcel Dekker: New York, 1995), 331–363. Accessed 24 May 2013. before it is discharged into the tank portion of the Jameson Cell (see Figure 4). The downcomer is designed to provide high-intensity mixing of the air and the slurry to generate a dense foam of fine bubbles and maximise the contact between the target mineral particles and the bubbles.G J Jameson and E V Manlapig, "Flotation cell design – experiences with the Jameson Cell," in: Extractive Metallurgy Conference, Perth, Western Australia, 2–4 October 1991 (The Australasian Institute of Mining and Metallurgy: Melbourne, 1991), 1–6. The probability of particle–bubble contact is "virtually 100%" with a slurry residence time in the downcomer of 5–10 seconds.
The high probability of particle–bubble contact, and subsequent short residence times (five to ten seconds in the downcomer, allows for a much more compact column design than conventional column flotation cells (see Figure 1). The fine nature of the bubbles (0.3 to 0.5 mm in diameter) gives them enhanced carrying capabilities for fine mineral particles. Fine bubbles also improve the separation of minerals, as they intensify the difference in the flotation kinetics of the valuable minerals from the gangue minerals, thus allowing higher grade concentrates to be produced.
The foam in the downcomer is about 50–60% air. Because of this, the pulp is distributed in the form of thin interfacial slurry films between the bubbles, providing an ideal environment for particle–bubble contact. Collection occurs by migration of the particles within the thin films, which are not much thicker than the diameter of the particles.
The best collection occurs when the volume of air roughly equals that of the injected slurry.