XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 597
mitigating measures for this type of equipment, it is impor-
tant to address the rate of evaporation from open body sur-
faces of mineral processing equipment.
The Dalton equation (1) is typically used to estimate
water loss (m
evap )from open bodies of water. However,
some of these equipment slurry surface conditions deviate
from that of a pond or a lake on which the Dalton equa-
tion was developed. In the case of flotation cells and col-
umn cells, the evaporation surface is not only defined by
the open area of the cell, but also by the size and number of
air bubbles being pushed through the cell. Consequently,
potential water loss from flotation cells would be greater
than what the Dalton equation would predict.
It was suggested that covering water reservoirs would
reduce the evaporation of recycled plant water, reducing
the need for the use mineralised ground make-up water.
This could in turn reduce corrosive wear of grinding media
significantly (Radziszewski, 2004). Today, covering water
reservoirs, flotation cells, thickeners, and any open body of
plant water is seen as a viable avenue to reduce water lost
through evaporation in mineral processing (Gunson et al.,
2012).
However, the covers for equipment with open bodies of
water should be designed as heat exchange surfaces where
water vapor condenses and falls back into the slurry or is
collected and pumped elsewhere in the process. In order
to increase the rate of condensation and the associate heat
transfer (Q
heat
o ),the outside of the cover would need to be
finned in a similar fashion as stationary equipment.
5. Trommels and Screens
This type of equipment has the potential to have high
evaporation rates (m
evap )as they are found at the discharge
of SAG mills where the slurry temperature is potentially
high. Assuming that the whole ore size distribution is now
“wetted,” the potential evaporation surface is undoubtedly
quite high. Consequently, trommels and screens need cov-
ers similar to those used for open body of water equipment
to reduce evaporation and increase heat loss (Q
heat
o ).
6. Pipes
Pipes do not present any risk of water loss through evapora-
tion. However, similar to tall stationary equipment, pipes
provide a lot of heat transfer area. Consequently, adding
Figure 3. A generic 50000 t/day mineral processing plant (Gunson et al., 2012)
mitigating measures for this type of equipment, it is impor-
tant to address the rate of evaporation from open body sur-
faces of mineral processing equipment.
The Dalton equation (1) is typically used to estimate
water loss (m
evap )from open bodies of water. However,
some of these equipment slurry surface conditions deviate
from that of a pond or a lake on which the Dalton equa-
tion was developed. In the case of flotation cells and col-
umn cells, the evaporation surface is not only defined by
the open area of the cell, but also by the size and number of
air bubbles being pushed through the cell. Consequently,
potential water loss from flotation cells would be greater
than what the Dalton equation would predict.
It was suggested that covering water reservoirs would
reduce the evaporation of recycled plant water, reducing
the need for the use mineralised ground make-up water.
This could in turn reduce corrosive wear of grinding media
significantly (Radziszewski, 2004). Today, covering water
reservoirs, flotation cells, thickeners, and any open body of
plant water is seen as a viable avenue to reduce water lost
through evaporation in mineral processing (Gunson et al.,
2012).
However, the covers for equipment with open bodies of
water should be designed as heat exchange surfaces where
water vapor condenses and falls back into the slurry or is
collected and pumped elsewhere in the process. In order
to increase the rate of condensation and the associate heat
transfer (Q
heat
o ),the outside of the cover would need to be
finned in a similar fashion as stationary equipment.
5. Trommels and Screens
This type of equipment has the potential to have high
evaporation rates (m
evap )as they are found at the discharge
of SAG mills where the slurry temperature is potentially
high. Assuming that the whole ore size distribution is now
“wetted,” the potential evaporation surface is undoubtedly
quite high. Consequently, trommels and screens need cov-
ers similar to those used for open body of water equipment
to reduce evaporation and increase heat loss (Q
heat
o ).
6. Pipes
Pipes do not present any risk of water loss through evapora-
tion. However, similar to tall stationary equipment, pipes
provide a lot of heat transfer area. Consequently, adding
Figure 3. A generic 50000 t/day mineral processing plant (Gunson et al., 2012)