3637
Analysis and Improvement of Flotation Circuits for
Polymetallic Ores
Yordana Flores, Yesica L. Botero, Luis A. Cisternas
Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Chile
Advanced Mining Technology Center (AMTC), Chile
ABSTRACT: The plant design for the flotation of polymetallic ores usually consists of a sequence of plants to
separate the valuable elements from the gangue. Usually, the tail or the bulk concentrate from one circuit is the
feed to the second circuit, and so on. More stream connections are rare, especially the stream recycling from
the downstream plant to the upstream plant. This work analyzes the integration of plants in polymetallic ore
flotation. Integration consists of the union between these plants beyond a tail or concentrate stream. First, plant
design is carried out using optimization to select the best alternative from a set of circuit alternatives. Then,
analysis is performed using global sensitivity and uncertainty analyses to identify bottlenecks. The results show
that these integrated plants’ design and analysis would introduce significant improvements. The advantages and
challenges of integrated polymetallic plants are highlighted.
INTRODUCTION
The mining industry faces significant challenges given
the increasing demand for metals under greater environ-
mental restrictions and more complex deposits with lower
grades. The circular economy has been established as a pos-
sible model given the impossibility of continuing with an
economy where resources once used are transformed into
waste. For an adequate application of the circular economy,
it is necessary to reduce material flows using loops to keep
resources in use. However, these loops should be as short
as possible to avoid the use of other materials and energy
resources (Cisternas et al. 2022).
Thus, it is necessary, on the one hand, to valorize all
the materials available in an ore and, on the other, to avoid
the reprocessing of a plant’s solid waste. From this perspec-
tive, any ore should be considered a polymetallic one if it
contains more than one species of value. The most com-
mon way to treat such polymetallic ores is to concentrate
one mineral first and consider the tail as the feed to the
following circuit where a second mineral is concentrated,
and so on. Several of these processes are not very efficient
with pour selectivity or low recoveries. Therefore, other
strategies must be studied to identify new processes, their
challenges, and their advantages.
Recently, a study was conducted on the polymetallic ore
flotation plant design (Botero et al., 2024). It is known that
there are a large number of flotation circuit configurations,
even in cases with few flotation stages. However, Botero et
al. (2024) demonstrated that despite the uncertainty in the
recoveries of each stage, there are few optimal structures for
a given problem, and few structures accumulate the highest
frequencies of occurrence or, in other words, have the great-
est chance of being the optimal structure. They also showed
that integrated design gives better economic, metallurgical,
and environmental results.
This work continues that study with a new case study to
validate some of the results previously found. Additionally,
it introduces global sensitivity analysis (GSA) as a way to
Analysis and Improvement of Flotation Circuits for
Polymetallic Ores
Yordana Flores, Yesica L. Botero, Luis A. Cisternas
Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Chile
Advanced Mining Technology Center (AMTC), Chile
ABSTRACT: The plant design for the flotation of polymetallic ores usually consists of a sequence of plants to
separate the valuable elements from the gangue. Usually, the tail or the bulk concentrate from one circuit is the
feed to the second circuit, and so on. More stream connections are rare, especially the stream recycling from
the downstream plant to the upstream plant. This work analyzes the integration of plants in polymetallic ore
flotation. Integration consists of the union between these plants beyond a tail or concentrate stream. First, plant
design is carried out using optimization to select the best alternative from a set of circuit alternatives. Then,
analysis is performed using global sensitivity and uncertainty analyses to identify bottlenecks. The results show
that these integrated plants’ design and analysis would introduce significant improvements. The advantages and
challenges of integrated polymetallic plants are highlighted.
INTRODUCTION
The mining industry faces significant challenges given
the increasing demand for metals under greater environ-
mental restrictions and more complex deposits with lower
grades. The circular economy has been established as a pos-
sible model given the impossibility of continuing with an
economy where resources once used are transformed into
waste. For an adequate application of the circular economy,
it is necessary to reduce material flows using loops to keep
resources in use. However, these loops should be as short
as possible to avoid the use of other materials and energy
resources (Cisternas et al. 2022).
Thus, it is necessary, on the one hand, to valorize all
the materials available in an ore and, on the other, to avoid
the reprocessing of a plant’s solid waste. From this perspec-
tive, any ore should be considered a polymetallic one if it
contains more than one species of value. The most com-
mon way to treat such polymetallic ores is to concentrate
one mineral first and consider the tail as the feed to the
following circuit where a second mineral is concentrated,
and so on. Several of these processes are not very efficient
with pour selectivity or low recoveries. Therefore, other
strategies must be studied to identify new processes, their
challenges, and their advantages.
Recently, a study was conducted on the polymetallic ore
flotation plant design (Botero et al., 2024). It is known that
there are a large number of flotation circuit configurations,
even in cases with few flotation stages. However, Botero et
al. (2024) demonstrated that despite the uncertainty in the
recoveries of each stage, there are few optimal structures for
a given problem, and few structures accumulate the highest
frequencies of occurrence or, in other words, have the great-
est chance of being the optimal structure. They also showed
that integrated design gives better economic, metallurgical,
and environmental results.
This work continues that study with a new case study to
validate some of the results previously found. Additionally,
it introduces global sensitivity analysis (GSA) as a way to