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Optimizing the Flocculation Efficiency of Fine Phosphate
Tailings: A Response Surface Methodology Investigation
Abdelilah Bergani, Yassine Taha, Yassine Ait Khouia, Mostafa Benzaazoua
Mohammed VI Polytechnic University (UM6P), Morocco
Rachid Hakkou
Cadi Ayyad University (UCA) &Mohammed VI Polytechnic University (UM6P), Morocco
ABSTRACT: Escalating global water stress and the extensive processing of phosphate ores require the
development of sustainable water management solutions. This study aims to improve water recovery from
fine phosphate tailings (FPTs) generated at the Youssoufia processing plant in Morocco. Comprehensive
characterization of FPTs revealed their composition, comprising silicates, carbonates, alumino-silicates, and
residual fluorapatite. Flocculation and sedimentation experiments with various flocculants determined anionic
polyacrylamides as most effective in enhancing flocculation and achieving water recovery rates above 80%.
The main factors influencing flocculation performance included flocculant dose, pH, mixing rate and time.
Employing an experimental design approach, the effects of those factors on solid-liquid separation of FPTs were
assessed, providing insights into their dewatering performance and interactions. The findings of this study will
contribute to the development of sustainable solutions for water management in phosphate processing plants,
addressing the dual challenges of water scarcity and efficient resource utilisation.
Keywords: water recycling flocculation dewatering optimization polyacrylamides.
INTRODUCTION
In the context of phosphate beneficiation operations, water
recovery from fine phosphate tailings, which are often
slurry-like residues containing a mixture of water, fine par-
ticles and residual reagents, is a critical aspect of environ-
mental sustainability (Eskanlou &Huang, 2021 Liu et al.,
2020). Flocculation can be strategically employed as a piv-
otal technique in this process, and it stands out as the most
widely utilized method due to its cost-effectiveness. In most
industrial applications this process is used as a pretreatment
step prior to the solid–liquid separation to recover water
by sedimentation of phosphate slurry (Mamghaderi et al.,
2021).
Flocculants are introduced into the slurry to enhance
the aggregation of fine particles, facilitating the formation
of larger and settleable flocs. As these flocs settle, they effec-
tively capture suspended the solids, leading to the clarifica-
tion of the supernatant (Boshrouyeh Ghandashtani et al.,
2022). The clarified water can then be recycled for various
mining processes such as grinding, wet classification, flota-
tion, or safely (in same cases) released into the environment
(Gunson et al., 2012 Luukkanen et al., 2022). Meanwhile,
the dewatered tailings can undergo further processing
(recovery of valuable elements, uses in the construction
sector, etc.), revalorization, or secured storage in tailings
impoundments (Kossoff et al., 2014). The implementation
Optimizing the Flocculation Efficiency of Fine Phosphate
Tailings: A Response Surface Methodology Investigation
Abdelilah Bergani, Yassine Taha, Yassine Ait Khouia, Mostafa Benzaazoua
Mohammed VI Polytechnic University (UM6P), Morocco
Rachid Hakkou
Cadi Ayyad University (UCA) &Mohammed VI Polytechnic University (UM6P), Morocco
ABSTRACT: Escalating global water stress and the extensive processing of phosphate ores require the
development of sustainable water management solutions. This study aims to improve water recovery from
fine phosphate tailings (FPTs) generated at the Youssoufia processing plant in Morocco. Comprehensive
characterization of FPTs revealed their composition, comprising silicates, carbonates, alumino-silicates, and
residual fluorapatite. Flocculation and sedimentation experiments with various flocculants determined anionic
polyacrylamides as most effective in enhancing flocculation and achieving water recovery rates above 80%.
The main factors influencing flocculation performance included flocculant dose, pH, mixing rate and time.
Employing an experimental design approach, the effects of those factors on solid-liquid separation of FPTs were
assessed, providing insights into their dewatering performance and interactions. The findings of this study will
contribute to the development of sustainable solutions for water management in phosphate processing plants,
addressing the dual challenges of water scarcity and efficient resource utilisation.
Keywords: water recycling flocculation dewatering optimization polyacrylamides.
INTRODUCTION
In the context of phosphate beneficiation operations, water
recovery from fine phosphate tailings, which are often
slurry-like residues containing a mixture of water, fine par-
ticles and residual reagents, is a critical aspect of environ-
mental sustainability (Eskanlou &Huang, 2021 Liu et al.,
2020). Flocculation can be strategically employed as a piv-
otal technique in this process, and it stands out as the most
widely utilized method due to its cost-effectiveness. In most
industrial applications this process is used as a pretreatment
step prior to the solid–liquid separation to recover water
by sedimentation of phosphate slurry (Mamghaderi et al.,
2021).
Flocculants are introduced into the slurry to enhance
the aggregation of fine particles, facilitating the formation
of larger and settleable flocs. As these flocs settle, they effec-
tively capture suspended the solids, leading to the clarifica-
tion of the supernatant (Boshrouyeh Ghandashtani et al.,
2022). The clarified water can then be recycled for various
mining processes such as grinding, wet classification, flota-
tion, or safely (in same cases) released into the environment
(Gunson et al., 2012 Luukkanen et al., 2022). Meanwhile,
the dewatered tailings can undergo further processing
(recovery of valuable elements, uses in the construction
sector, etc.), revalorization, or secured storage in tailings
impoundments (Kossoff et al., 2014). The implementation