1
25-032
Enrichment of Sphalerite and Hemimorphite in Zinc Tailing for
the Potential Recovery of Gallium and Germanium
Hazal Melis Aytac
Missouri University of Science &Technology,
Rolla, MO, USA
Fardis Nakhaei
Missouri University of Science &Technology,
Rolla, MO, USA
Lana Alagha
Missouri University of Science &Technology,
Rolla, MO, USA
ABSTRACT
Gallium (Ga) and Germanium (Ge) are essential strate-
gic elements that are extensively used as semiconductors
in many technological fields. Owing to their essential
uses and supply disruption, Ga and Ge are deemed criti-
cal by the U.S. They are typically found as substitutions
or inclusions in zinc minerals. However, their distribu-
tions within zinc minerals are not well understood. To
address this, trace element and mineralogy analyses of rep-
resentative samples obtained from an old high-zinc-grade
tailing were performed using various qualitative and quan-
titative techniques. These techniques included Inductively
Coupled Plasma Mass Spectrometry (ICP-MS), Tescan
Integrated Mineralogical Analysis (TIMA) with Scanning
Electron Microscopy (SEM) and X-ray Diffraction (XRD).
Moreover, bench-scale froth flotation tests were conducted
to enrich zinc minerals, the major hosts of Ga and Ge,
using PAX as a collector, Na2S as a sulfidizer, Pb(NO3)2 as
an activator, and MIBC as a frother. Comprehensive char-
acterization analyses of the flotation products showed
significant enrichment of Zn, Ga and Ge in the flotation
concentrates.
Introduction
Gallium (Ga) and germanium (Ge) have been categorized
as critical and strategic elements by the U.S. and many other
countries owing to their unique semiconductor properties
utilized in renewable energy, telecommunications and
defense systems [1]. Ga, a soft metal, is primarily used in
essential micro-electronic components, laser diodes, light-
emitting diodes (LEDs), digital integrated circuits, semi-
conductors and transistors either in the forms of gallium
arsenide (GaAs) and gallium nitride (GaN). Germanium,
meanwhile, plays a key role particularly in the manufactur-
ing of fiber optics cables (GeCl₄), optical lens and plastic
polyethylene terephthalate (PET) resin (GeO₂) [2,3]. The
limited reserves and geopolitical dependencies have led
to potential supply risk. Therefore, ensuring a stable and
domestic supply of Ga and Ge has become an urgent prior-
ity for the U.S. to decrease the import rates and meet the
increasing demand for these elements.
Ga and Ge can be recovered as byproducts from metal-
lurgical processing of base metal sulfides, bauxite ores, and
steelmaking wastes. Ga is currently recovered as a by-prod-
uct from the bauxite processing for aluminum production,
with less amounts also produced from sphalerite rich ore
processing during zinc production. Similarly, zinc residues
serve as sources for Ge production as well as fly ash from
coal burning [3–5]. The growing demand for these criti-
cal elements has led to the exploration of non-traditional
sources such as metallurgical slags, and sulfide tailings [6,7].
This study aims to enrich Ga and Ge in sulfide tail-
ing by concentrating zinc (Zn) minerals (major hosts of Ga
and Ge) using froth flotation process. Prior to the flotation
25-032
Enrichment of Sphalerite and Hemimorphite in Zinc Tailing for
the Potential Recovery of Gallium and Germanium
Hazal Melis Aytac
Missouri University of Science &Technology,
Rolla, MO, USA
Fardis Nakhaei
Missouri University of Science &Technology,
Rolla, MO, USA
Lana Alagha
Missouri University of Science &Technology,
Rolla, MO, USA
ABSTRACT
Gallium (Ga) and Germanium (Ge) are essential strate-
gic elements that are extensively used as semiconductors
in many technological fields. Owing to their essential
uses and supply disruption, Ga and Ge are deemed criti-
cal by the U.S. They are typically found as substitutions
or inclusions in zinc minerals. However, their distribu-
tions within zinc minerals are not well understood. To
address this, trace element and mineralogy analyses of rep-
resentative samples obtained from an old high-zinc-grade
tailing were performed using various qualitative and quan-
titative techniques. These techniques included Inductively
Coupled Plasma Mass Spectrometry (ICP-MS), Tescan
Integrated Mineralogical Analysis (TIMA) with Scanning
Electron Microscopy (SEM) and X-ray Diffraction (XRD).
Moreover, bench-scale froth flotation tests were conducted
to enrich zinc minerals, the major hosts of Ga and Ge,
using PAX as a collector, Na2S as a sulfidizer, Pb(NO3)2 as
an activator, and MIBC as a frother. Comprehensive char-
acterization analyses of the flotation products showed
significant enrichment of Zn, Ga and Ge in the flotation
concentrates.
Introduction
Gallium (Ga) and germanium (Ge) have been categorized
as critical and strategic elements by the U.S. and many other
countries owing to their unique semiconductor properties
utilized in renewable energy, telecommunications and
defense systems [1]. Ga, a soft metal, is primarily used in
essential micro-electronic components, laser diodes, light-
emitting diodes (LEDs), digital integrated circuits, semi-
conductors and transistors either in the forms of gallium
arsenide (GaAs) and gallium nitride (GaN). Germanium,
meanwhile, plays a key role particularly in the manufactur-
ing of fiber optics cables (GeCl₄), optical lens and plastic
polyethylene terephthalate (PET) resin (GeO₂) [2,3]. The
limited reserves and geopolitical dependencies have led
to potential supply risk. Therefore, ensuring a stable and
domestic supply of Ga and Ge has become an urgent prior-
ity for the U.S. to decrease the import rates and meet the
increasing demand for these elements.
Ga and Ge can be recovered as byproducts from metal-
lurgical processing of base metal sulfides, bauxite ores, and
steelmaking wastes. Ga is currently recovered as a by-prod-
uct from the bauxite processing for aluminum production,
with less amounts also produced from sphalerite rich ore
processing during zinc production. Similarly, zinc residues
serve as sources for Ge production as well as fly ash from
coal burning [3–5]. The growing demand for these criti-
cal elements has led to the exploration of non-traditional
sources such as metallurgical slags, and sulfide tailings [6,7].
This study aims to enrich Ga and Ge in sulfide tail-
ing by concentrating zinc (Zn) minerals (major hosts of Ga
and Ge) using froth flotation process. Prior to the flotation