Improve Copper Yield in Flotation0 pages

Metals & Mining

Application Data Sheet

Improve Copper Yield in Flotation Tanks
Benefits

Increase product yield
Reduce reagent consumption
Reduced labor requirements

Background
Rich copper concentrate is produced from crude copper sulfide ore
by means of a flotation process that takes advantage of the physical
and chemical properties of small copper ore particles. To maximize
the yield of copper, pH control is necessary in the flotation tanks.

Process
Crushed ore (containing 1 to 2 % copper), along with water and a
lime slurry, is fed into a ball mill. This rotating drum contains steel
balls that further crush the ore to a fine powder. When the ore / lime
slurry emerges from the mill, it is fed to a rake classifier. Particles that
are too large to pass from the classifier are returned to the mill, while
the overflow is discharged to flotation cells.
Air is injected into the flotation cells, and foaming agents are added,
creating a froth. Copper ore particles, due to their relatively light
weight, become a part of this froth, while heavier particles, such as
iron ore, do not. The copper-rich concentrate, containing 20 to 40 %
copper, is then separated from the solution for further processing
(Figure 1).

pH Control
The condition of the froth is directly dependent on pH. The flow
rate of lime slurry is therefore regulated to keep the pH within the
acceptable range. If pH is too low, iron will be entrapped as well as
copper, decreasing the value of the copper ultimately recovered.
If too much lime is added, the result is a dilute froth that requires
additional concentration in later stages, increasing operating costs
and wasting lime.

Instrumentation
The 396P TUpH™ Insertion/Submersion pH/ORP sensor is especially
recommended for pH control in the high solids environment that is
characteristic of lime slurries. Also, the reference junction is rugged
and highly resistant to coating, resulting in reduced maintenance
and process downtime.
The 396P is available both with and without a preamplifier
and is compatible with all Rosemount Analytical analyzers and
transmitters, including the 5081 pH/ORP Smart Two-Wire
Transmitter, and the multi-parameter 1056 and 56 dual input
analyzers.

396P pH/ORP TUpH Sensor

Polypropylene reference junction for
longer sensor life in process solutions
containing heavy solids.
Disposable, one-piece construction
is convenient and economical
where minimal troubleshooting and
maintenance downtime are of prime
importance.
Versatile. Can be used in numerous loop configurations with all
Rosemount Analytical and other manufacturers’ instruments.