Continuous design improvements have resulted in a flotation technology with high availability, long component life and low operating costs.
20 years of development
The first Jameson Cells were a big improvement on columns though further refinement of the design was required to create a technology that consistently performed under demanding operating conditions. Xstrata Technology’s operation and engineering personnel have worked with Jameson Cell users for 20 years to continuously improve the robustness and reliability of the Jameson Cell. Two decades of significant advances have culminated in the latest model, the Mark IV Cell. The Mark IV Jameson Cell incorporates:
- Feed recycle system to ensure stable cell and downcomer operation, maintaining optimum performance independent of feed fluctuations.
- Low wear, high discharge coefficient, slurry lens orifice.
- Flexible feed nozzle allowing quick and easy inspection and precise alignment of the plunging jet to maximise metallurgical performance.
- Improved above froth or in-froth wash water system.
Evolution of Downcomers
The introduction of the Mark III downcomer in 2000 halved the number of downcomer parts and re-located all maintenance parts to the outside of the downcomer thus allowing for easier and faster maintenance access. The Mark IV downcomer consists of two primary components – the slurry lens and the AISE valve.
The Slurry Lens
With the release of the Mark III downcomer the original ceramic orifice plates were replaced with a slurry lens. The benefits included a shallow slurry entry angle which optimised slurry flow and maximised component wear life, a high discharge coefficient which reduced feed pump power by 10-15%, and improved slurry jet formation resulting in less splashing, improved vacuum and higher air entrainment. Additionally the location of the slurry lens compared to the orifice plate meant that the effective downcomer length was increased improving mixing zone residence time and air-to-pulp ratios.
From a maintenance perspective the slurry lens is less prone to breaking and significantly easier to replace than orifice plates. If a lens becomes blocked or needs replacing it is now a ten minute job that can be performed “on-the-run”. The downcomer in question is isolated, the slurry lens removed and either cleaned or replaced, and then the downcomer is brought back on line.
The AISE Valve
The introduction of the proprietary Air Isolating – Slurry Eliminating Valve introduced automatic air isolation on downcomer shutdown. This eliminates slurry build-up in air lines and reduces air line wear and blockages.