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Assessment of Depression Methods of Activated Pyrite
Yesica L Botero, Luis A. Cisternas
Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Chile
Advanced Mining Technology Center (AMTC), Chile
Ruth Salazar
Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Chile
ABSTRACT: The pyrite depression of activated pyrite is of interest in several situations. For example, separation
of pyrite by depression from the concentrate is required in desulfurization processes that include a bulk
concentrate. This work presents an analysis of three ways to depress activated pyrite. Those methods include
regrinding, ultrasonic, and hydrogen peroxide treatment. The research includes physicochemical studies such as
FTIR, adsorption, SEM, zeta potential, and microflotation tests. Two collectors were analyzed Potassium amyl
xanthate (PAX) and Sodium Dialkyl DithioPhosphate (DTP). The results indicate that ultrasonic treatment
allows the decomposition of PAX on the pyrite surface but does not decompose DTP. Hydrogen peroxide
decomposes both PAX and DTP that have been adsorbed on the pyrite surface. Finally, flotation results allowed
us to get the optimal parameters to run the depression of activated pyrite. All the procedures proposed seem
to work. Nevertheless, the most suitable methodology was the H2O2 treatment since the recovery went down
around 7% for PAX (68% less) and around 5.4% for DTP (70% less). All this information gives us insights into
the depression of pyrite that has been first activated and could be successfully depressed, which enables us to face
the future challenges of integrating the desulfurization process in the flotation plant.
INTRODUCTION
Porphyry copper deposits have relatively low ore grades
Therefore, high tonnage exploitation is necessary. One
consequence is that significant quantities of solid waste are
produced (approximately 98% of the extracted material)
compared to the copper units recovered. These wastes can
be subdivided into waste rock and tailings. Around eight
billion tons of tailings are generated annually, of which,
according to Global Tailing Review, 46% is due to cop-
per production (Oberle et al., 2020). Tailings are gener-
ated after the copper ore beneficiation process and end up
containing minerals such as pyrrhotite, arsenopyrite, and
pyrite. The last one is present in a significant proportion
in these wastes. These minerals can have a large environ-
mental impact because in the presence of oxygen and water,
they oxidize and can produce acid mine drainage (AMD)
(Texeira et al., 2023). The potential generation of AMD
depends on the mineralogical waste and mineral dissolution
rates. Therefore, the behavior of this type of waste can be
very different. For this reason, waste assessment and man-
agement are a challenge for the mining industry (Blowes et
al., 2014 Paktunc &Davé, 2000).
The current strategy implemented for waste manage-
ment is known as End-of-Pipe technology, which consists
of AMD mitigation. These methodologies are focused on
waste that already contains acidifying species. Reprocessing
Assessment of Depression Methods of Activated Pyrite
Yesica L Botero, Luis A. Cisternas
Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Chile
Advanced Mining Technology Center (AMTC), Chile
Ruth Salazar
Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Chile
ABSTRACT: The pyrite depression of activated pyrite is of interest in several situations. For example, separation
of pyrite by depression from the concentrate is required in desulfurization processes that include a bulk
concentrate. This work presents an analysis of three ways to depress activated pyrite. Those methods include
regrinding, ultrasonic, and hydrogen peroxide treatment. The research includes physicochemical studies such as
FTIR, adsorption, SEM, zeta potential, and microflotation tests. Two collectors were analyzed Potassium amyl
xanthate (PAX) and Sodium Dialkyl DithioPhosphate (DTP). The results indicate that ultrasonic treatment
allows the decomposition of PAX on the pyrite surface but does not decompose DTP. Hydrogen peroxide
decomposes both PAX and DTP that have been adsorbed on the pyrite surface. Finally, flotation results allowed
us to get the optimal parameters to run the depression of activated pyrite. All the procedures proposed seem
to work. Nevertheless, the most suitable methodology was the H2O2 treatment since the recovery went down
around 7% for PAX (68% less) and around 5.4% for DTP (70% less). All this information gives us insights into
the depression of pyrite that has been first activated and could be successfully depressed, which enables us to face
the future challenges of integrating the desulfurization process in the flotation plant.
INTRODUCTION
Porphyry copper deposits have relatively low ore grades
Therefore, high tonnage exploitation is necessary. One
consequence is that significant quantities of solid waste are
produced (approximately 98% of the extracted material)
compared to the copper units recovered. These wastes can
be subdivided into waste rock and tailings. Around eight
billion tons of tailings are generated annually, of which,
according to Global Tailing Review, 46% is due to cop-
per production (Oberle et al., 2020). Tailings are gener-
ated after the copper ore beneficiation process and end up
containing minerals such as pyrrhotite, arsenopyrite, and
pyrite. The last one is present in a significant proportion
in these wastes. These minerals can have a large environ-
mental impact because in the presence of oxygen and water,
they oxidize and can produce acid mine drainage (AMD)
(Texeira et al., 2023). The potential generation of AMD
depends on the mineralogical waste and mineral dissolution
rates. Therefore, the behavior of this type of waste can be
very different. For this reason, waste assessment and man-
agement are a challenge for the mining industry (Blowes et
al., 2014 Paktunc &Davé, 2000).
The current strategy implemented for waste manage-
ment is known as End-of-Pipe technology, which consists
of AMD mitigation. These methodologies are focused on
waste that already contains acidifying species. Reprocessing