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First-Principles Study on the Decisive Role of Electronic
Structure in the Flotation of Cu-Activated Sphalerite
Chongjun Liu, Yangge Zhu, Guiye Wu, Tong Lu, Huinan Liu, Yanhong Ma
State Key Laboratory of Mineral Processing, BGRIMM Technology Group
ABSTRACT: In this study, Density Functional Theory (DFT) was employed to investigate the adsorption of
xanthate on the sphalerite (110) surface and copper-activated sphalerite (110) surface. Results show that copper
has fewer electrons in anti-bonding orbits than zinc during bonding with xanthate, resulting in better stability.
The d- band center of copper is higher than that of zinc, therefore copper has better adsorption ability than zinc.
Thermodynamic studies show that the adsorption of xanthate on the mineral surface conforms to the Langmuir
isothermal equation, and the adsorption enthalpy of xanthate on the surface of copper-activated sphalerite is
larger than that on the surface of sphalerite.
Keywords: sphalerite Cu-activated d-band centre DFT
INTRODUCTION
Zinc is a vital industrial material that plays a pivotal role
in contemporary society. Sphalerite serves as a significant
source of Zn. Froth flotation is one of the most extensively
employed methods for selectively recovering sphalerite. The
hydrophobicity of minerals can be enhanced, leading to an
increased flotation recovery, by incorporating appropriate
collectors into the pulp. However, it is widely acknowl-
edged that the recovery of sphalerite is difficult to enhance
solely through the use of conventional collectors such as
xanthate during flotation. To enhance the flotation recov-
ery of sphalerite, it is necessary to introduce an activator
(such as CuSO4) during the flotation process.
To further improve the flotation recovery of sphaler-
ite and establish a theoretical foundation for the flotation
reagent molecular design, the mechanism of sphalerite acti-
vated by copper sulfate has been deeply studied[1–4]. Most
researchers believe that the substitution of the Zn atom with
the Cu atom is the main mechanism for Cu activation of the
sphalerite surface. After activation, the xanthate collector
interacts with the Cu atoms [5–7] .In the past decade, the
quantum chemistry theory was given more attention in
the fundamental research of mineral processing due to its
advantage in acquiring the micro information of minerals
and their interaction with flotation reagents. It has been
used extensively to simulate un-activated and Cu-activated
sphalerite and their interactions with xanthate [8–10] .The
results of these simulations provide a deep understanding
of the atomic and molecular mechanism related to sphal-
erite flotation. However, these simulations mainly focused
on the differences in the interactions between xanthate and
metal atoms, which remain unexplained from an electronic
structure perspective.
The interaction between xanthate and metal ions on
mineral surfaces is determined by the electron distribu-
tion of metal ions. According to molecular orbital theory
(MOT), the distribution of electrons in bonding and anti-
bonding orbitals can have a huge impact on interatomic
bonding. Therefore, a detailed study of the electronic struc-
ture of mineral surface-active sites is necessary to investigate
First-Principles Study on the Decisive Role of Electronic
Structure in the Flotation of Cu-Activated Sphalerite
Chongjun Liu, Yangge Zhu, Guiye Wu, Tong Lu, Huinan Liu, Yanhong Ma
State Key Laboratory of Mineral Processing, BGRIMM Technology Group
ABSTRACT: In this study, Density Functional Theory (DFT) was employed to investigate the adsorption of
xanthate on the sphalerite (110) surface and copper-activated sphalerite (110) surface. Results show that copper
has fewer electrons in anti-bonding orbits than zinc during bonding with xanthate, resulting in better stability.
The d- band center of copper is higher than that of zinc, therefore copper has better adsorption ability than zinc.
Thermodynamic studies show that the adsorption of xanthate on the mineral surface conforms to the Langmuir
isothermal equation, and the adsorption enthalpy of xanthate on the surface of copper-activated sphalerite is
larger than that on the surface of sphalerite.
Keywords: sphalerite Cu-activated d-band centre DFT
INTRODUCTION
Zinc is a vital industrial material that plays a pivotal role
in contemporary society. Sphalerite serves as a significant
source of Zn. Froth flotation is one of the most extensively
employed methods for selectively recovering sphalerite. The
hydrophobicity of minerals can be enhanced, leading to an
increased flotation recovery, by incorporating appropriate
collectors into the pulp. However, it is widely acknowl-
edged that the recovery of sphalerite is difficult to enhance
solely through the use of conventional collectors such as
xanthate during flotation. To enhance the flotation recov-
ery of sphalerite, it is necessary to introduce an activator
(such as CuSO4) during the flotation process.
To further improve the flotation recovery of sphaler-
ite and establish a theoretical foundation for the flotation
reagent molecular design, the mechanism of sphalerite acti-
vated by copper sulfate has been deeply studied[1–4]. Most
researchers believe that the substitution of the Zn atom with
the Cu atom is the main mechanism for Cu activation of the
sphalerite surface. After activation, the xanthate collector
interacts with the Cu atoms [5–7] .In the past decade, the
quantum chemistry theory was given more attention in
the fundamental research of mineral processing due to its
advantage in acquiring the micro information of minerals
and their interaction with flotation reagents. It has been
used extensively to simulate un-activated and Cu-activated
sphalerite and their interactions with xanthate [8–10] .The
results of these simulations provide a deep understanding
of the atomic and molecular mechanism related to sphal-
erite flotation. However, these simulations mainly focused
on the differences in the interactions between xanthate and
metal atoms, which remain unexplained from an electronic
structure perspective.
The interaction between xanthate and metal ions on
mineral surfaces is determined by the electron distribu-
tion of metal ions. According to molecular orbital theory
(MOT), the distribution of electrons in bonding and anti-
bonding orbitals can have a huge impact on interatomic
bonding. Therefore, a detailed study of the electronic struc-
ture of mineral surface-active sites is necessary to investigate