XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2085
reverse course as they move towards the vortex finder, even-
tually reaching the overflow. Since this operation involves
the separation of solids, various blocking issues are associ-
ated with it. Roping is one such problem that can restrict
underflow discharge, resulting in the overlap of overflow
and underflow particles. Identifying spray discharge, rop-
ing or near-roping conditions is crucial for maintaining
separation efficiencies (Neesse and Dueck 2007). Air core
studies play a significant role in detecting the near roping or
roping conditions in operation (Pérez et al., 2018).
The formation and stability of air-core are explained
in detail in literature (Diddi, Jampana, and Mangadoddy
2022 Rakesh, Kumar Reddy, and Narasimha 2014).
During the flow separation process, a radial pressure gra-
dient occurs from the wall of the hydrocyclone to the
central part. As a result, a low-pressure zone occurs at
the central part of the hydrocyclone. Atmospheric air or
entrapped air in conduits enters the low-pressure area from
the vortex finder and spigot openings and forms the air
core. Understanding air core stability and geometry gives
insights into the system’s operating state and helps identify
the roping phenomena in operation (Diddi, Jampana, and
Mangadoddy 2022 Pathak et al. 2022 Pérez et al., 2018).
Therefore, continuous monitoring of the air core dynam-
ics is crucial for maintaining stable and efficient operation
(Diddi, Jampana, and Mangadoddy 2022).
Electrical Resistance Tomography (ERT) is a non-inva-
sive technique used for in-situ measurement of the air core
and flow visualization in hydrocyclones. Given the lower
conductivity of air in comparison to water, the ERT system
allows for visualization of air core formation in the hydro-
cyclone (Reddy 2016). The ERT process involves deploying
conductive sensors on the wall of the process vessel to intro-
duce smaller AC currents (in milli Amperes) and then record
the voltage differences. This data allows for reconstructing
the conductivity distribution of the process fluids within
the hydrocyclone by solving forward and inverse problems.
The mathematical formulations and challenges of the for-
ward and inverse problems are explained elsewhere (Diddi,
Jampana, and Mangadoddy 2022). The image reconstruc-
tion algorithm converts the recorded voltage measurements
to interpretable images (Dickin and Wang 1996 Williams,
Ilyas, and Dyakowski 1995).
Previous ERT research has generally been accurate in
assessing the form of the air core, especially when it comes
to locating the hydrocyclone’s center of low conductivity
(Williams et al. 1999 Vakamalla et al. 2014 Williams,
Ilyas, and Dyakowski 1995 Gutierrez et al. 2000 Rakesh,
Kumar Reddy, and Narasimha 2014 Diddi, Jampana, and
Mangadoddy 2022). Despite the ERT’s advantages, nota-
bly its higher scanning rate, achieving a precise definition
of phase boundaries is a significant challenge. ERT’s spa-
tial resolution is relatively limited compared to hard-field
tomographic techniques. To be precise, the spatial resolu-
tion of ERT is between 5 and 10% of the equipment diam-
eter (Reddy 2016).
The application of advanced image reconstruction
algorithms can potentially yield substantial improvements
Figure 1. Hydrocyclone schematic design
reverse course as they move towards the vortex finder, even-
tually reaching the overflow. Since this operation involves
the separation of solids, various blocking issues are associ-
ated with it. Roping is one such problem that can restrict
underflow discharge, resulting in the overlap of overflow
and underflow particles. Identifying spray discharge, rop-
ing or near-roping conditions is crucial for maintaining
separation efficiencies (Neesse and Dueck 2007). Air core
studies play a significant role in detecting the near roping or
roping conditions in operation (Pérez et al., 2018).
The formation and stability of air-core are explained
in detail in literature (Diddi, Jampana, and Mangadoddy
2022 Rakesh, Kumar Reddy, and Narasimha 2014).
During the flow separation process, a radial pressure gra-
dient occurs from the wall of the hydrocyclone to the
central part. As a result, a low-pressure zone occurs at
the central part of the hydrocyclone. Atmospheric air or
entrapped air in conduits enters the low-pressure area from
the vortex finder and spigot openings and forms the air
core. Understanding air core stability and geometry gives
insights into the system’s operating state and helps identify
the roping phenomena in operation (Diddi, Jampana, and
Mangadoddy 2022 Pathak et al. 2022 Pérez et al., 2018).
Therefore, continuous monitoring of the air core dynam-
ics is crucial for maintaining stable and efficient operation
(Diddi, Jampana, and Mangadoddy 2022).
Electrical Resistance Tomography (ERT) is a non-inva-
sive technique used for in-situ measurement of the air core
and flow visualization in hydrocyclones. Given the lower
conductivity of air in comparison to water, the ERT system
allows for visualization of air core formation in the hydro-
cyclone (Reddy 2016). The ERT process involves deploying
conductive sensors on the wall of the process vessel to intro-
duce smaller AC currents (in milli Amperes) and then record
the voltage differences. This data allows for reconstructing
the conductivity distribution of the process fluids within
the hydrocyclone by solving forward and inverse problems.
The mathematical formulations and challenges of the for-
ward and inverse problems are explained elsewhere (Diddi,
Jampana, and Mangadoddy 2022). The image reconstruc-
tion algorithm converts the recorded voltage measurements
to interpretable images (Dickin and Wang 1996 Williams,
Ilyas, and Dyakowski 1995).
Previous ERT research has generally been accurate in
assessing the form of the air core, especially when it comes
to locating the hydrocyclone’s center of low conductivity
(Williams et al. 1999 Vakamalla et al. 2014 Williams,
Ilyas, and Dyakowski 1995 Gutierrez et al. 2000 Rakesh,
Kumar Reddy, and Narasimha 2014 Diddi, Jampana, and
Mangadoddy 2022). Despite the ERT’s advantages, nota-
bly its higher scanning rate, achieving a precise definition
of phase boundaries is a significant challenge. ERT’s spa-
tial resolution is relatively limited compared to hard-field
tomographic techniques. To be precise, the spatial resolu-
tion of ERT is between 5 and 10% of the equipment diam-
eter (Reddy 2016).
The application of advanced image reconstruction
algorithms can potentially yield substantial improvements
Figure 1. Hydrocyclone schematic design