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Impact of a Residual Anionic Polyacrylamide and Its Mechanical
Degradation Level on Chalcopyrite Flotation
Felipe Arcos
Department of metallurgical engineering, University of Concepcion, Chile
Leopoldo Gutierrez
Department of metallurgical engineering, University of Concepcion, Chile
Water Research Center for Agriculture and Mining (CRHIAM), Universidad de Concepcion, Chile
ABSTRACT: Water recirculation in mineral processing plants is an effective solution to water scarcity. However,
this causes some operational challenges. In this work, the depressing effect of a residual anionic polyacrylamide
(PAM) on chalcopyrite flotation under different conditions of mechanical degradation, pH and concentration is
presented. Tests of micro-flotation, reagent adsorption and induction time were performed. The results showed
an inverse relationship between PAM degradation and chalcopyrite depression at pH values of 7 and 9. On
the other hand, for the highly sheared flocculant, the chalcopyrite depression increased with pH, reaching the
greatest impact at pH 11. These effects have not been previously studied and may be important for the industry.
INTRODUCTION
Currently, the mining industry and especially the process-
ing of copper minerals has two great challenges. The first
of them is related to the progressive decrease in the metal-
lic grade in the minerals extracted from the mine and to
the increase in demand for copper worldwide (Peng and
Bhambhani, 2021). On the other hand, the protagonist
of the second challenge is precisely the water resource
since conventional water or fresh water, which is increas-
ingly scarce, today also has a series of environmental and
social limitations for its use, especially in arid areas such as
northern Chile (Wang and Peng, 2014). In many mining
regions, water scarcity is crucial, so managing and reducing
freshwater consumption is a necessity. In Chile, the highest
levels of water scarcity are reached in the Antofagasta and
Atacama regions (Alvez et al., 2020), which are the main
mining areas in the north of the country.
Within this framework, the main measures used as a
solution to these problems have been both the recirculation
and reuse of process water (Witecki et al., 2022) and the use
of seawater (Jeldres et al., 2016). According to the Chilean
Copper Commission (Cochilco), it is expected that by
2030 continental water will represent less than 40% of the
total water required in mining (Cochilco, 2020). The recir-
culation of water and its reuse in other unit operations in
the processing plant can generate the presence of unwanted
residual reagents that affect the efficiency of these processes
(Castro and Laskowski, 2015 Muzinda and Schreithofer,
2018). Additionally, recirculated water may contain solid
particles due to imperfections in thickening and/or filtra-
tion technologies (Le, Schreithofer, et al., 2020). In this
sense, water quality has a significant impact on the flota-
tion process, however, no specific studies are carried out on
this variable for the design and operation of concentration
plants (Suyantara et al., 2018). Therefore, copper produc-
tion may be even more affected considering the low grades
currently managed.
Impact of a Residual Anionic Polyacrylamide and Its Mechanical
Degradation Level on Chalcopyrite Flotation
Felipe Arcos
Department of metallurgical engineering, University of Concepcion, Chile
Leopoldo Gutierrez
Department of metallurgical engineering, University of Concepcion, Chile
Water Research Center for Agriculture and Mining (CRHIAM), Universidad de Concepcion, Chile
ABSTRACT: Water recirculation in mineral processing plants is an effective solution to water scarcity. However,
this causes some operational challenges. In this work, the depressing effect of a residual anionic polyacrylamide
(PAM) on chalcopyrite flotation under different conditions of mechanical degradation, pH and concentration is
presented. Tests of micro-flotation, reagent adsorption and induction time were performed. The results showed
an inverse relationship between PAM degradation and chalcopyrite depression at pH values of 7 and 9. On
the other hand, for the highly sheared flocculant, the chalcopyrite depression increased with pH, reaching the
greatest impact at pH 11. These effects have not been previously studied and may be important for the industry.
INTRODUCTION
Currently, the mining industry and especially the process-
ing of copper minerals has two great challenges. The first
of them is related to the progressive decrease in the metal-
lic grade in the minerals extracted from the mine and to
the increase in demand for copper worldwide (Peng and
Bhambhani, 2021). On the other hand, the protagonist
of the second challenge is precisely the water resource
since conventional water or fresh water, which is increas-
ingly scarce, today also has a series of environmental and
social limitations for its use, especially in arid areas such as
northern Chile (Wang and Peng, 2014). In many mining
regions, water scarcity is crucial, so managing and reducing
freshwater consumption is a necessity. In Chile, the highest
levels of water scarcity are reached in the Antofagasta and
Atacama regions (Alvez et al., 2020), which are the main
mining areas in the north of the country.
Within this framework, the main measures used as a
solution to these problems have been both the recirculation
and reuse of process water (Witecki et al., 2022) and the use
of seawater (Jeldres et al., 2016). According to the Chilean
Copper Commission (Cochilco), it is expected that by
2030 continental water will represent less than 40% of the
total water required in mining (Cochilco, 2020). The recir-
culation of water and its reuse in other unit operations in
the processing plant can generate the presence of unwanted
residual reagents that affect the efficiency of these processes
(Castro and Laskowski, 2015 Muzinda and Schreithofer,
2018). Additionally, recirculated water may contain solid
particles due to imperfections in thickening and/or filtra-
tion technologies (Le, Schreithofer, et al., 2020). In this
sense, water quality has a significant impact on the flota-
tion process, however, no specific studies are carried out on
this variable for the design and operation of concentration
plants (Suyantara et al., 2018). Therefore, copper produc-
tion may be even more affected considering the low grades
currently managed.