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An evaluation of cyclone performance to improve the quality of cyclone underflow material for tailings disposal. By John Wates and Michael Knight Fraser Alexander. Use of cyclones for tailings?. Underflow. Overflow. Self raising configuration Downstream Centreline Upstream
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An evaluation of cyclone performance to improve the quality of cyclone underflow material for tailings disposal By John Wates and Michael Knight Fraser Alexander
Use of cyclones for tailings? Underflow Overflow Self raising configuration Downstream Centreline Upstream Location of cyclones Off wall cyclones trucked into place Off wall cyclones pumped into place On wall cyclones SUITABLE FOR COARSE TAILINGS
The problem Split not achieved Geometry Non compliance Tried! Split increase Specs not achieved Stacking not achieved Non compliance
Cyclone theory Inputs PSD Solids concentration Rheology Parameters influencing underflow properties (PSD & W/C) Diameter Vortex finder Spigot size Pressure/vacuum Operation
Why are underflow properties important? Shear strength 15% passing 75 micron/200 mesh Liquefaction potential (Drainage, PSD and Compaction) Permeability contrast (kuf > 100 x kof) Geometry Stacking Split to underflow Underflow Overflow
What we investigated Spigot/vortex finder combinations Pressure Barrel extension Pressurization Split
Conclusions There is an optimum vortex finder and spigot size 135/65 Feed pressure of 180 kPa is the optimum Barrel extensions and pressurization improve split Splitting u/f discharge improves stacking (1:6 to 1:5) Stacking angle improves with increasing u/f RD and as % passing 75 micron increases (1:5 for 10% passing 1:50 for >25% passing) Split decreases as u/f RD increases and % passing 75 micron decreases
Opportunities Improved efficiency and control in split Refinement of underflow criteria Handling finer tailings Higher rates of rise for finer tailings Reducing water consumption
Acknowledgements Co-author Michael Knight DRD Anglo Gold Ashanti The Fraser Alexander team