2358
Switchable Frother Technology For Improved Plant Operations
T. Bhambhani, E. Arinaitwe, C.McMillan
Syensqo Mineral Processing Research and Innovation, Stamford, CT USA
ABSTRACT: Base metal (particularly Cu) operations are continually increasing throughput due to lower grade
ore bodies, and to capitalize on high metal prices. Increasing throughput invariably results in a coarser particle
size distribution for the feed, resulting in a greater proportion of poorly liberated particles. Floating these
requires strong frothers, which carry over to the cleaners causing problems such as deep froths, overfrothing, and
poor dewatering. Solutions to these problems often include mixtures or “blends” of strong and weak frothers,
invariably leading to compromises in either the rougher or cleaner circuits. Syensqo has developed a novel
frother technology that can be strong in the rougher circuit, but switch to a weaker frother in the cleaner
circuit. The benefits of this include the potential for higher throughput, improved recovery of coarse particles,
reduced circulating loads, improved thickener overflow clarity and higher overall recoveries. This reagent has
been studied at pilot and full plant scale, and results from piloting are discussed. In addition, critical coalescence
concentration (CCC95) values were generated using bubble size measurements on both rougher and cleaner pH
ranges, which show the increase in CCC95 with time.
Keywords: Frothers, Switchable, Cleaner Recovery, coarse particle flotation
BACKGROUND AND UNMET NEEDS
With ever increasing metal prices, mines are always look-
ing to increase throughput. The increased throughput in
the same flowsheet invariably results in the feed having a
coarser particle size distribution. In order to recover the
coarse values, plants need to use stronger flotation reagents
to ensure acceptable rougher recoveries.
In particular, strong frothers are critical to float coarse
particles they create a froth that drains water more slowly,
enabling more support for coarse particles that have
detached from bubbles. Although strong frothers (typically
glycols and glycol ethers) work well in the roughers to aid
the recovery of these particles, the froth is too persistent for
the cleaner circuit because the cleaner particle size distri-
bution is much finer (than rougher). The persistent froth
makes the cleaning process inefficient as insolubles and
other hydrophilic gangue minerals are unable to drain from
this type of froth. The persistent froth also causes problems
during transport or pumping of the slurry, and downstream
in the dewatering stages. Weak frothers, on the other hand,
work well to drain the froth in the cleaner circuit to remove
the hydrophilic gangue, but they do not support the coarse
particles in the rougher.
The typical compromise approach to manage this is to
use formulations (mixtures) of strong and weak frothers.
However, the amount of “strong” frother that is typically
added to the mixture is such that the downstream froth
can be managed without overfrothing and without desta-
bilizing the cleaning circuits, which is typically 5 to 20%
of the total amount of frother. Even with this approach,
with some ores (typically containing problematic non-sul-
fide gangue) they will see overfrothing in the cleaners or
Switchable Frother Technology For Improved Plant Operations
T. Bhambhani, E. Arinaitwe, C.McMillan
Syensqo Mineral Processing Research and Innovation, Stamford, CT USA
ABSTRACT: Base metal (particularly Cu) operations are continually increasing throughput due to lower grade
ore bodies, and to capitalize on high metal prices. Increasing throughput invariably results in a coarser particle
size distribution for the feed, resulting in a greater proportion of poorly liberated particles. Floating these
requires strong frothers, which carry over to the cleaners causing problems such as deep froths, overfrothing, and
poor dewatering. Solutions to these problems often include mixtures or “blends” of strong and weak frothers,
invariably leading to compromises in either the rougher or cleaner circuits. Syensqo has developed a novel
frother technology that can be strong in the rougher circuit, but switch to a weaker frother in the cleaner
circuit. The benefits of this include the potential for higher throughput, improved recovery of coarse particles,
reduced circulating loads, improved thickener overflow clarity and higher overall recoveries. This reagent has
been studied at pilot and full plant scale, and results from piloting are discussed. In addition, critical coalescence
concentration (CCC95) values were generated using bubble size measurements on both rougher and cleaner pH
ranges, which show the increase in CCC95 with time.
Keywords: Frothers, Switchable, Cleaner Recovery, coarse particle flotation
BACKGROUND AND UNMET NEEDS
With ever increasing metal prices, mines are always look-
ing to increase throughput. The increased throughput in
the same flowsheet invariably results in the feed having a
coarser particle size distribution. In order to recover the
coarse values, plants need to use stronger flotation reagents
to ensure acceptable rougher recoveries.
In particular, strong frothers are critical to float coarse
particles they create a froth that drains water more slowly,
enabling more support for coarse particles that have
detached from bubbles. Although strong frothers (typically
glycols and glycol ethers) work well in the roughers to aid
the recovery of these particles, the froth is too persistent for
the cleaner circuit because the cleaner particle size distri-
bution is much finer (than rougher). The persistent froth
makes the cleaning process inefficient as insolubles and
other hydrophilic gangue minerals are unable to drain from
this type of froth. The persistent froth also causes problems
during transport or pumping of the slurry, and downstream
in the dewatering stages. Weak frothers, on the other hand,
work well to drain the froth in the cleaner circuit to remove
the hydrophilic gangue, but they do not support the coarse
particles in the rougher.
The typical compromise approach to manage this is to
use formulations (mixtures) of strong and weak frothers.
However, the amount of “strong” frother that is typically
added to the mixture is such that the downstream froth
can be managed without overfrothing and without desta-
bilizing the cleaning circuits, which is typically 5 to 20%
of the total amount of frother. Even with this approach,
with some ores (typically containing problematic non-sul-
fide gangue) they will see overfrothing in the cleaners or