XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 93
principally water supply but also other material specific
characteristics. A prime example requiring dry grinding
is Portland cement which cannot be ground wet as it will
begin the setting process.
Air-swept SAG mills and ball mills, hammer mills,
roll mills, and HPGRs are examples of the equipment
used for dry grinding (Bearman, 2019). The advantages of
dry grinding include saving water, lower consumption of
grinding media and liners, elimination of expensive drying
equipment, and easier shut-down and restart. The disad-
vantages of dry grinding include higher noise, dust control
and higher energy consumption (Chelgani, 2022).
Magnetic
Magnetic separation is used to separate minerals that exhibit
sufficiently different magnetic susceptibilities as shown in
Table 1. Magnetite (Fe2O3·FeO, simplified to Fe3O4) is a
magnetic iron ore that is usually separated from its silica
(SiO2) host rock using magnetic separators (Ripke, 2019).
Dry magnetic cobbing was implemented at Cleveland-
Cliffs Northshore mine that simultaneously upgraded the
feed and generated a gravel byproduct used to build their
tailings dam.
Gravity
Gravity separation exploits the specific gravity differences
between the liberated minerals. Dry gravity separation
equipment includes the air jig, air table, air-dense medium
fluidized bed separator, Knelson concentrator, and the reflux
concentrator. Each of these pieces of equipment are con-
cisely described in Dry Mineral Processing (Chelgani, 2022).
While dry (pneumatic) gravity separation is possible, it has
become increasingly rare compared to wet (hydraulic) grav-
ity separation. Aplan (Fuerstenau M. C. and K. Han, eds.
Figure 2. Approximate range of applicability of various concentrating devices, after Aplan (Fuerstenau M. C. and K. Han, eds.
2003)
principally water supply but also other material specific
characteristics. A prime example requiring dry grinding
is Portland cement which cannot be ground wet as it will
begin the setting process.
Air-swept SAG mills and ball mills, hammer mills,
roll mills, and HPGRs are examples of the equipment
used for dry grinding (Bearman, 2019). The advantages of
dry grinding include saving water, lower consumption of
grinding media and liners, elimination of expensive drying
equipment, and easier shut-down and restart. The disad-
vantages of dry grinding include higher noise, dust control
and higher energy consumption (Chelgani, 2022).
Magnetic
Magnetic separation is used to separate minerals that exhibit
sufficiently different magnetic susceptibilities as shown in
Table 1. Magnetite (Fe2O3·FeO, simplified to Fe3O4) is a
magnetic iron ore that is usually separated from its silica
(SiO2) host rock using magnetic separators (Ripke, 2019).
Dry magnetic cobbing was implemented at Cleveland-
Cliffs Northshore mine that simultaneously upgraded the
feed and generated a gravel byproduct used to build their
tailings dam.
Gravity
Gravity separation exploits the specific gravity differences
between the liberated minerals. Dry gravity separation
equipment includes the air jig, air table, air-dense medium
fluidized bed separator, Knelson concentrator, and the reflux
concentrator. Each of these pieces of equipment are con-
cisely described in Dry Mineral Processing (Chelgani, 2022).
While dry (pneumatic) gravity separation is possible, it has
become increasingly rare compared to wet (hydraulic) grav-
ity separation. Aplan (Fuerstenau M. C. and K. Han, eds.
Figure 2. Approximate range of applicability of various concentrating devices, after Aplan (Fuerstenau M. C. and K. Han, eds.
2003)