XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 107
range of applications where it would be advantageous to
preserve the properties of the particle. In breakage charac-
terization, for example, insights into breakage mechanisms
are being investigated using XRT by measuring liberation
before and after the breakage of an intact rock mass (Zhang
et al, 2024).
Much work has to be performed, however, before XRT
can be used routinely for mineral liberation analysis. The
biggest challenge is to develop methods of differentiating
minerals of similar density. Spectral analysis and Advanced
Intelligence (AI) techniques are being explored as methods
to achieve this objective.
Ultimately flotation is a surface-driven phenomenon,
and it is important in flotation diagnosis to be able to mea-
sure the chemical speciation on particle surfaces. Time-of-
Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a
technique which measures the chemical species of the top
2–3 atomic layers of the mineral surfaces in the form of
secondary ions (elements, organic and inorganic ions, mol-
ecules, etc.) with high sensitivity (i.e., down to ppb). This is
critical information as it enables identification of the chem-
istry drivers affecting flotation.
One novel application of ToF-SIMS is the compari-
son of reagent or ion species on particle surfaces in flota-
tion concentrate and tailing streams. Advanced statistical
analysis (e.g., Principal Component Analysis) is applied to
analyze the mass spectra and identify the major surface spe-
cies differing between the concentrate and tailing streams,
providing insights into what is promoting or inhibiting
flotation (Brito e Abreu et al., 2010). In an industrial case-
study conducted by Runge et al. (2021), for example, it
was used to determine that unwanted copper recovery dur-
ing a pre-flotation stage was occurring due to a flotation
mechanism rather than entrainment. It was concluded that
residual collector in the process water was responsible for
the presence of collector on the surfaces of chalcopyrite in
the concentrate streams. This knowledge enabled strategies
to be devised for decontamination of the process water to
reduce chalcopyrite flotation in the pre-flotation stage and
thus reduce losses to the tailings (Forbes et al., 2022).
The application of this type of analysis in flotation cir-
cuit diagnostic studies offers a step forward as it allows for
the definitive determination of underlying mechanisms and
enables solutions for improving flotation efficiency to be
discovered. It has many applications in flotation and poten-
tially other processes like comminution and dewatering.
For example, it can be used to:
• Understand the effect of different breakage technolo-
gies on the mineral particle surfaces (e.g., dry vs wet)
• Understand the effect of different grinding condi-
tions (grinding media, Eh/pH) on the oxidation of
mineral particles
• Identify the chemistry drivers for the flotation of
valuable minerals or gangue
• Understand the impact of process water on the flo-
tation performance and recycling of process streams
Techniques such as XRT and ToF-SIMS also have potential
for use in geometallurgical studies, providing information
that could be used to predict and optimize future perfor-
mance of different ores. Use of these techniques, however, is
currently restricted to the research community and are too
expensive and time consuming to perform in conjunction
with routine diagnostic programs. To bridge this gap, there
is a need for more automation during measurement and the
development of better software tools to analyze and process
the data to provide meaningful information more quickly
and accurately.
There are also other complementary technologies
that provide an opportunity for a more in-depth analy-
sis of particle mineralogy. Techniques such as Laser
Ablation Inductively Coupled Plasma Mass Spectrometry
(LA-ICP-MS) and synchrotron radiation X-ray microprobe
(SRXRF) now enable the measurement of small inclusions
of elements within a mineral matrix (Chew et al, 2021
Li and Li, 2016). Jefferson et al, 2024, for example, did
SRXRF measurements showing that copper present in the
pyrite mineral grains was likely responsible for the floatabil-
ity of pyrite in the Mt Isa Copper concentrator, rather than
the previously held belief that it was carbonaceous pyrite
association.
With the development of analytical tools with greater
levels of resolution and accuracy, the industry now has a
greater ability to definitively determine mechanisms of
flotation recovery. Improved understanding opens the
doorway for industry to develop the solutions required to
improve flotation recovery and selectivity and make step
changes in circuit performance.
Online Characterization
An autonomous process operates as much as practicable
with minimal direct human intervention. To do this well, it
needs not only to reliably perform its functions predictably
and deal successfully with unexpected and complex events,
but it also needs to clearly communicate its behavior and
decisions that are perceived to be rational. The system also
needs to be accepted and understood by the human opera-
tor and any human or cultural biases or disincentives for
its use should be managed (Abbass, Scholz &Reid, 2018).
range of applications where it would be advantageous to
preserve the properties of the particle. In breakage charac-
terization, for example, insights into breakage mechanisms
are being investigated using XRT by measuring liberation
before and after the breakage of an intact rock mass (Zhang
et al, 2024).
Much work has to be performed, however, before XRT
can be used routinely for mineral liberation analysis. The
biggest challenge is to develop methods of differentiating
minerals of similar density. Spectral analysis and Advanced
Intelligence (AI) techniques are being explored as methods
to achieve this objective.
Ultimately flotation is a surface-driven phenomenon,
and it is important in flotation diagnosis to be able to mea-
sure the chemical speciation on particle surfaces. Time-of-
Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a
technique which measures the chemical species of the top
2–3 atomic layers of the mineral surfaces in the form of
secondary ions (elements, organic and inorganic ions, mol-
ecules, etc.) with high sensitivity (i.e., down to ppb). This is
critical information as it enables identification of the chem-
istry drivers affecting flotation.
One novel application of ToF-SIMS is the compari-
son of reagent or ion species on particle surfaces in flota-
tion concentrate and tailing streams. Advanced statistical
analysis (e.g., Principal Component Analysis) is applied to
analyze the mass spectra and identify the major surface spe-
cies differing between the concentrate and tailing streams,
providing insights into what is promoting or inhibiting
flotation (Brito e Abreu et al., 2010). In an industrial case-
study conducted by Runge et al. (2021), for example, it
was used to determine that unwanted copper recovery dur-
ing a pre-flotation stage was occurring due to a flotation
mechanism rather than entrainment. It was concluded that
residual collector in the process water was responsible for
the presence of collector on the surfaces of chalcopyrite in
the concentrate streams. This knowledge enabled strategies
to be devised for decontamination of the process water to
reduce chalcopyrite flotation in the pre-flotation stage and
thus reduce losses to the tailings (Forbes et al., 2022).
The application of this type of analysis in flotation cir-
cuit diagnostic studies offers a step forward as it allows for
the definitive determination of underlying mechanisms and
enables solutions for improving flotation efficiency to be
discovered. It has many applications in flotation and poten-
tially other processes like comminution and dewatering.
For example, it can be used to:
• Understand the effect of different breakage technolo-
gies on the mineral particle surfaces (e.g., dry vs wet)
• Understand the effect of different grinding condi-
tions (grinding media, Eh/pH) on the oxidation of
mineral particles
• Identify the chemistry drivers for the flotation of
valuable minerals or gangue
• Understand the impact of process water on the flo-
tation performance and recycling of process streams
Techniques such as XRT and ToF-SIMS also have potential
for use in geometallurgical studies, providing information
that could be used to predict and optimize future perfor-
mance of different ores. Use of these techniques, however, is
currently restricted to the research community and are too
expensive and time consuming to perform in conjunction
with routine diagnostic programs. To bridge this gap, there
is a need for more automation during measurement and the
development of better software tools to analyze and process
the data to provide meaningful information more quickly
and accurately.
There are also other complementary technologies
that provide an opportunity for a more in-depth analy-
sis of particle mineralogy. Techniques such as Laser
Ablation Inductively Coupled Plasma Mass Spectrometry
(LA-ICP-MS) and synchrotron radiation X-ray microprobe
(SRXRF) now enable the measurement of small inclusions
of elements within a mineral matrix (Chew et al, 2021
Li and Li, 2016). Jefferson et al, 2024, for example, did
SRXRF measurements showing that copper present in the
pyrite mineral grains was likely responsible for the floatabil-
ity of pyrite in the Mt Isa Copper concentrator, rather than
the previously held belief that it was carbonaceous pyrite
association.
With the development of analytical tools with greater
levels of resolution and accuracy, the industry now has a
greater ability to definitively determine mechanisms of
flotation recovery. Improved understanding opens the
doorway for industry to develop the solutions required to
improve flotation recovery and selectivity and make step
changes in circuit performance.
Online Characterization
An autonomous process operates as much as practicable
with minimal direct human intervention. To do this well, it
needs not only to reliably perform its functions predictably
and deal successfully with unexpected and complex events,
but it also needs to clearly communicate its behavior and
decisions that are perceived to be rational. The system also
needs to be accepted and understood by the human opera-
tor and any human or cultural biases or disincentives for
its use should be managed (Abbass, Scholz &Reid, 2018).