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Online Elemental Analysis of Copper Concentrator Feed
Utilizing PGNAA Technology
Garry Noble, Tom Strombotne, Kevin Gordon
Thermo Fisher Scientific
ABSTRACT: The elemental composition of plant feed at copper concentrators is critical data to have available on
a real-time basis. Having this critical data can provide feedback control for mine management and feedforward
control for grinding and flotation. Due to the difficulty in actual sampling and obtaining a true representative
sample at this point in the process, a robust analysis technique is required to measure a coarse bulk sample on a
moving conveyor. PGNAA (Prompt Gamma Neutron Activation Analysis) technology is a deeply penetrating
measuring technique that is independent of particle size and sample heterogeneity in geological materials. Results
from an actual PGNAA analyzer operating on a copper stockpile feed in comparison to existing elemental
analysis data sources will be presented in this paper.
INTRODUCTION
Prompt Gamma Neutron Activation Analysis (PGNAA) is
a nuclear analytical technique that has been widely used for
decades in various applications. The history of this technol-
ogy can be traced back to the 1960s when scientists began
to explore the possibility of using nuclear reactions to deter-
mine the elemental composition of various materials.
PGNAA technology has since emerged as a power tool
used for process control in various industries predominantly
in cement, coal, sinter as well as other process control appli-
cations. The principle of PGNAA lies in the interaction of
neutrons with atomic nuclei. When a sample is bombarded
with neutrons, elements within the material will undergo
nuclear interactions, resulting in the emittance of gamma
rays. These gamma rays can then be detected, resulting in a
spectrum allowing for analysis to determine the elemental
content of the material.
Employing PGNAA technology, most often on a con-
veyor belt, offers several advantages to other technologies
that have also been used for online analysis. One of the
advantages of this technology is its penetrating nature of
analysis. Neutron and resultant gamma ray penetration
depth is well documented (e.g., Shue, and Singh 2014)
allowing the entire material flow to be analyzed versus other
techniques that can offer minimal penetration or simply
surface measurements. This allows for a true understanding
of the entire material’s elemental composition.
Another key factor is uniformity of analysis that ensures
the analyzer is measuring all of the material on the conveyor
belt and not just the center of the material. It’s key that
any PGNAA analyzer is designed to maximize uniformity
in most applications. PGNAA analyzer design, including
neutron source and detector configuration, can have a sig-
nificant impact on the analytical performance and derived
value to customers (e.g., Noble 2020). Calibration meth-
odology is also critical to ensure accuracy is maintained
under variable mass flow conditions typically present on
feed conveyors.
BACKGROUND
While wider adoption of on-line analysis and advanced pro-
cess control has been achieved in the past several decades,
Online Elemental Analysis of Copper Concentrator Feed
Utilizing PGNAA Technology
Garry Noble, Tom Strombotne, Kevin Gordon
Thermo Fisher Scientific
ABSTRACT: The elemental composition of plant feed at copper concentrators is critical data to have available on
a real-time basis. Having this critical data can provide feedback control for mine management and feedforward
control for grinding and flotation. Due to the difficulty in actual sampling and obtaining a true representative
sample at this point in the process, a robust analysis technique is required to measure a coarse bulk sample on a
moving conveyor. PGNAA (Prompt Gamma Neutron Activation Analysis) technology is a deeply penetrating
measuring technique that is independent of particle size and sample heterogeneity in geological materials. Results
from an actual PGNAA analyzer operating on a copper stockpile feed in comparison to existing elemental
analysis data sources will be presented in this paper.
INTRODUCTION
Prompt Gamma Neutron Activation Analysis (PGNAA) is
a nuclear analytical technique that has been widely used for
decades in various applications. The history of this technol-
ogy can be traced back to the 1960s when scientists began
to explore the possibility of using nuclear reactions to deter-
mine the elemental composition of various materials.
PGNAA technology has since emerged as a power tool
used for process control in various industries predominantly
in cement, coal, sinter as well as other process control appli-
cations. The principle of PGNAA lies in the interaction of
neutrons with atomic nuclei. When a sample is bombarded
with neutrons, elements within the material will undergo
nuclear interactions, resulting in the emittance of gamma
rays. These gamma rays can then be detected, resulting in a
spectrum allowing for analysis to determine the elemental
content of the material.
Employing PGNAA technology, most often on a con-
veyor belt, offers several advantages to other technologies
that have also been used for online analysis. One of the
advantages of this technology is its penetrating nature of
analysis. Neutron and resultant gamma ray penetration
depth is well documented (e.g., Shue, and Singh 2014)
allowing the entire material flow to be analyzed versus other
techniques that can offer minimal penetration or simply
surface measurements. This allows for a true understanding
of the entire material’s elemental composition.
Another key factor is uniformity of analysis that ensures
the analyzer is measuring all of the material on the conveyor
belt and not just the center of the material. It’s key that
any PGNAA analyzer is designed to maximize uniformity
in most applications. PGNAA analyzer design, including
neutron source and detector configuration, can have a sig-
nificant impact on the analytical performance and derived
value to customers (e.g., Noble 2020). Calibration meth-
odology is also critical to ensure accuracy is maintained
under variable mass flow conditions typically present on
feed conveyors.
BACKGROUND
While wider adoption of on-line analysis and advanced pro-
cess control has been achieved in the past several decades,