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Flotation cells: Sludge level and foaminterface
measurementMining Prosonic M FMU40
Flotation cell
arrangement
Flotation cell
arrangement
Installed Prosonic M
FMU40
Features
Prosonic M FMU40 ultrasonic level de-vice with plug in display
for on site set-up
Compact 2-wire, HART device enablesalso remote programming
Robust IP68/NEMA 4X aluminiumhousing with R/NPT 1 sensor
processconnection
Benefits
Quick on-site setup via a plain languagedisplay -time and cost
saving due touniform operating philosophy
Excellent 2 mm (0,08) accuracy up to1 m (3 ft) measuring range
(otherwise0,2 % of adjusted measuring range)
Robust non plastic housing Wide measuring range of the Prosonic
M
series measuring from 25 cm (10) to15 m (50 ft)
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Instruments International
Endress+Hauser GmbH+Co. KG
Instruments International
P.O. Box 2222
79574 Weil am Rhein
Germany
Tel. +49 7621 975 02
Fax +49 7621 975 345
http://www.endress.com
[email protected]
CS 008B/11/en/01.05
55001830
IMPR/INDD 2.0
Typical copper mine separation
process
Flotation is used in gold, copper, lead, zinc
and coal to recover fine mineral particlesfiner than 0.5 mm
(0,02)Cell size ranges from 5 m3 to 200 m3
(178 - 7142 ft3) Cell Control parametersinclude:
Level & interface measurement Slurry pH control Flow meters
for frothing agent dosing Slurry flow and valve control using
elec-
tromagnetic flow meters
Application and process description
The copper processing area may consist of
both oxide and sulphide plants. Oxide andmixed ores are treated
by heap-leaching,solvent extraction and electro-winning(SX-EW).
Sulphide ore is crushed, groundand treated by flotation.
Run-of-minesulphide ore enters the primary gyratorycrusher prior to
transport to two parallelgrinding circuits, each consisting of a
SAGmill and a ball mill. Secondary closed circuitgrinding includes
cyclone classifiers, from
which the overflow feeds the flotationcircuit.
Flotation concentrate is thickened to 50 %
solids for slurry transport in a pipelineto the refinery where
it is thickened andfiltered before shipment world-wide. Airis blown
into the tanks and agitated like agiant blender, producing a foamy
froth. Thechalcopyrite grains become coated withxanthate molecules
with their hydrophobicends waving around trying desperately toget
out of the water.
Optimize your Flotation Cells Instrumentsfor control
They attach themselves to the oily airbubbles which become
coated with chal-copyrite grains as they rise to the surface
and flow over the edge of the tank. In thismanner through a
series of steps the copperore is concentrated to an eventual value
ofover 28 % copper. Waste rock particles donot adhere to the
bubbles and drop to thebottom of the tank. The waste material
thatcomes out of the bottom of the tanks at thetail end of this
process is called tailings. Itis nothing more than ground-up rock
withthe copper minerals removed.
Ultrasonic measurement at the flotati-
on cells
In flotation, the finely ground ore is mixed
with water to form a slurry. Certainchemicals or reagents that
only coat thedesired copper minerals are added in smallamounts.
Rising air bubbles capture thecoated mineral particles and float
them tothe surface where they are skimmed off anddried. This dried
material is called copperconcentrate and is approximately 30
%copper, 27 % iron and 33 % sulphur.
Measuring the slurry to bubble interfaceis important to control
the quality of theprocess. The density of the foam bubblesis high
enough to reflect ultrasonic pulses
from a continuous ultrasonic level sensor.Using a two channel
Prosonic S level trans-mitter called an FMU90, one FDU91
sensormeasures the distance to the bubble surfaceand the 2nd. FDU91
sensor is measuringthe distance to a disk. A float is swimmingon
the interface slurry / foam. A rod witha disk at the top is fixed
on the float. Theultrasonic device is measuring the distance
to the disk and so actually measuring theinterface. Fig. 1 shows
the float and diskarrangement.
The operating mode Difference h1/h2on the Prosonic S FMU90 is
reading thethickness of the bubble layer.
Fig. 1
