3552 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
et al., 2022], which is a big gap compared with the utiliza-
tion rate of 60% in western countries[Lemos et al., 2023].
Thus, the issue of GT and DT disposal is imminent.
The effective and sustainable utilization of tailings has
long been a subject of research and development[Barcelos
et al., 2020, Lyu et al., 2020]. Many experts have confirmed
that the utilization of those tailings is feasible. Ince used
GT to produce cement mortar, monitored its compressive
strength, porosity, and freeze-thaw cycle resistance over nine
months, significantly improving the performance of cement
mortar containing gold tailings[Ince, 2019]. Kuranchie has
reported that the utilization of iron tailings, GT, fly ash,
and slag in Western Australia, where the nature of some
of the waste is conducive to cost-effective and sustainable
use as road and rail embankment materials[Kuranchie et
al., 2013]. Çelik uses GT as a admixture of up to 25%
can enchance the properties of Portland cement[Çelik et
al., 2006]. Zhu et al. use GT to replace magnesium oxide
magnesia (MgO, M) in Magnesium potassium phosphate
cement (MKPC) instead of M. Processing properties, den-
sification, and compressive strength are improved. When
the substitution ratio is 10%, the compressive strength of
the cement increased by 114.94%[Zhu et al., 2022]. The
use of GT as the primary raw material to prepare auto-
claved aerated concrete (ACC) is proposed by Yang et al.
The results reveals that when the specific surface area of
GT is 367 m2/kg, the bulk density of the ACC designed
with 62% of the additive is 584 kg m–3, and the compres-
sive strength is 5.85 MPa[Yang et al., 2019]. However,
low-threshold and poor value-added product technologies
mainly dominate the comprehensive utilization of tailings,
and utilization technologies need to be further developed.
In this paper, preparation of novel permeable bricks
with GT and DT as the primary raw materials is pro-
posed. The process involves in combining GT and DT
with kaolin to prepare recycled aggregate, then wrapping it
with medium-low temperature binder and preparing per-
meable bricks by pressing and sintering. The main factors
affecting the mechanical and water permeability proper-
ties of permeable bricks were highlighted. Meanwhile, the
microforms and pore structures were characterized using
XRD, SEM, and industrial CT analyses, and the optimal
process and the principle of constructing microforms and
pore structures of permeable bricks using GT and DT as
the primary raw materials were obtained. The study results
provide a new way for the high-value consumption of GT
and DT and broaden the scope of selecting raw materials
for permeable bricks, which can help construct a “sponge
city” at a lower cost.
EXPERIMENT
Raw Materials
The GT and GT used in this experiment were from South
Africa. Those are the by-products obtained after the benefi-
ciation of gold and diamond ores and without pre-treated
before use. The kaolin and binder used in this experiment
are commonly available commercial products. The main
chemical compositions of GT, DT, and kaolin were shown
in Table 1. The mineral phases of GT, DT, and kaolin were
shown in Figure 1. As revealed in Table 1, the chemical
composition of GT mainly includes SiO2, Al2O3, Fe2O3,
SO3, K2O, in addition to a small amount of MgO, CaO,
Na2O. Notably, GT contained less impurities, and with
simple composition, which is suitable for sintered prod-
ucts chemical composition of DT mainly includes SiO2,
MgO, Fe2O3, etc. DT has a complex composition, thus
it can be used as auxiliary materials to adjust the content
of the required components in the material. The physical
composition of GT is relatively simple, the main phases
are quartz, muscovite, and kaolinite, which is conducive to
the preparation of sintered building materials. DT has a
complex physical composition, the main phases are quartz,
kaolinite, albite, phengite, calcite and katophorite of DT
are also a good complement to the preparation of sintered
building materials.
Based on the results of chemical and physical composi-
tion analyses of GT, DT and kaolin, a base mix ratio with
DT, GT and kaolin as the main raw materials was designed
according to the molar ratio of SiO2:CaO:Al2O3 of 12:1:2
to prepare recycled aggregate, and then binder was wrapped
around the surface of recycled aggregate to prepare perme-
able bricks, as shown in Table 2.
Firstly, GT, DT, and kaolin were mixed well in pro-
portion, placed in a drum granulator, granulated, and
Table 1. Main chemical composition of GT, DT and kaolin (wt%)
Chemical
Composition Na
2 O MgO Al
2 O
3 SiO
2 P
2 O
5 SO
3 K
2 O CaO TiO
2 Fe
2 O
3 LOI
DT 0.91 18.06 8.89 48.47 0.29 0.14 1.69 7.60 0.67 9.16 3.51
GT 0.37 0.86 10.30 78.84 0.11 1.68 1.47 0.58 0.30 3.12 2.19
Kaolin 0.07 0.17 37.63 43.16 0.07 — 0.13 0.23 1.39 0.43 16.62
et al., 2022], which is a big gap compared with the utiliza-
tion rate of 60% in western countries[Lemos et al., 2023].
Thus, the issue of GT and DT disposal is imminent.
The effective and sustainable utilization of tailings has
long been a subject of research and development[Barcelos
et al., 2020, Lyu et al., 2020]. Many experts have confirmed
that the utilization of those tailings is feasible. Ince used
GT to produce cement mortar, monitored its compressive
strength, porosity, and freeze-thaw cycle resistance over nine
months, significantly improving the performance of cement
mortar containing gold tailings[Ince, 2019]. Kuranchie has
reported that the utilization of iron tailings, GT, fly ash,
and slag in Western Australia, where the nature of some
of the waste is conducive to cost-effective and sustainable
use as road and rail embankment materials[Kuranchie et
al., 2013]. Çelik uses GT as a admixture of up to 25%
can enchance the properties of Portland cement[Çelik et
al., 2006]. Zhu et al. use GT to replace magnesium oxide
magnesia (MgO, M) in Magnesium potassium phosphate
cement (MKPC) instead of M. Processing properties, den-
sification, and compressive strength are improved. When
the substitution ratio is 10%, the compressive strength of
the cement increased by 114.94%[Zhu et al., 2022]. The
use of GT as the primary raw material to prepare auto-
claved aerated concrete (ACC) is proposed by Yang et al.
The results reveals that when the specific surface area of
GT is 367 m2/kg, the bulk density of the ACC designed
with 62% of the additive is 584 kg m–3, and the compres-
sive strength is 5.85 MPa[Yang et al., 2019]. However,
low-threshold and poor value-added product technologies
mainly dominate the comprehensive utilization of tailings,
and utilization technologies need to be further developed.
In this paper, preparation of novel permeable bricks
with GT and DT as the primary raw materials is pro-
posed. The process involves in combining GT and DT
with kaolin to prepare recycled aggregate, then wrapping it
with medium-low temperature binder and preparing per-
meable bricks by pressing and sintering. The main factors
affecting the mechanical and water permeability proper-
ties of permeable bricks were highlighted. Meanwhile, the
microforms and pore structures were characterized using
XRD, SEM, and industrial CT analyses, and the optimal
process and the principle of constructing microforms and
pore structures of permeable bricks using GT and DT as
the primary raw materials were obtained. The study results
provide a new way for the high-value consumption of GT
and DT and broaden the scope of selecting raw materials
for permeable bricks, which can help construct a “sponge
city” at a lower cost.
EXPERIMENT
Raw Materials
The GT and GT used in this experiment were from South
Africa. Those are the by-products obtained after the benefi-
ciation of gold and diamond ores and without pre-treated
before use. The kaolin and binder used in this experiment
are commonly available commercial products. The main
chemical compositions of GT, DT, and kaolin were shown
in Table 1. The mineral phases of GT, DT, and kaolin were
shown in Figure 1. As revealed in Table 1, the chemical
composition of GT mainly includes SiO2, Al2O3, Fe2O3,
SO3, K2O, in addition to a small amount of MgO, CaO,
Na2O. Notably, GT contained less impurities, and with
simple composition, which is suitable for sintered prod-
ucts chemical composition of DT mainly includes SiO2,
MgO, Fe2O3, etc. DT has a complex composition, thus
it can be used as auxiliary materials to adjust the content
of the required components in the material. The physical
composition of GT is relatively simple, the main phases
are quartz, muscovite, and kaolinite, which is conducive to
the preparation of sintered building materials. DT has a
complex physical composition, the main phases are quartz,
kaolinite, albite, phengite, calcite and katophorite of DT
are also a good complement to the preparation of sintered
building materials.
Based on the results of chemical and physical composi-
tion analyses of GT, DT and kaolin, a base mix ratio with
DT, GT and kaolin as the main raw materials was designed
according to the molar ratio of SiO2:CaO:Al2O3 of 12:1:2
to prepare recycled aggregate, and then binder was wrapped
around the surface of recycled aggregate to prepare perme-
able bricks, as shown in Table 2.
Firstly, GT, DT, and kaolin were mixed well in pro-
portion, placed in a drum granulator, granulated, and
Table 1. Main chemical composition of GT, DT and kaolin (wt%)
Chemical
Composition Na
2 O MgO Al
2 O
3 SiO
2 P
2 O
5 SO
3 K
2 O CaO TiO
2 Fe
2 O
3 LOI
DT 0.91 18.06 8.89 48.47 0.29 0.14 1.69 7.60 0.67 9.16 3.51
GT 0.37 0.86 10.30 78.84 0.11 1.68 1.47 0.58 0.30 3.12 2.19
Kaolin 0.07 0.17 37.63 43.16 0.07 — 0.13 0.23 1.39 0.43 16.62