Zinc Plant Expansion and Modification for Increased Metals …
369
(2) cobalt, nickel, and cadmium removal, and (3) polishing. All steps utilize zinc
powder for the cementation reaction, whereas antimony trioxide is added as activator to the second stage for efficient cobalt removal. To control the chloride leached
from concentrates, a chloride removal step is integrated to the new solution purification plant. The chloride removal is based on Outotec technology utilizing cuprous
oxide formed in the copper removal step. After the polishing stage, there is a gypsum
removal step for lowering the Ca concentration in solution by cooling and precipitation [3]. The last step in the expanded process is a new zinc electrowinning plant. The
zinc cathodes from the new electrowinning are transported to the Aleazin facility of
Peñoles for melting and casting.
Some nominal flow figures are given for reference: The concentrate feed to DL
is around 31 ton/h of dry mass, and the total flow to solution purification is around
450 m
3 /h. The calcine feed, being approx. 53 ton/h, was not affected by the expansion.
Implementation
Peñoles consulted Outotec for the conceptual and basic engineering of the total leaching and solution purification expansion. Leaching tests both in batch and continuous
mode with several concentrates of Peñoles proved the suitability of DL and formed
the basis for the design. Several stages of conceptual process engineering were executed, focusing mainly on how to integrate the new sections optimally in the existing
plant. The basic engineering including process, equipment, layout, piping, electrification, instrumentation, and automation design provided data for cost calculations
and offers, leading finally to the investment decision by Peñoles.
All the key process equipment of the new leaching and purification areas were in
Outotec delivery scope; 57 reactors, five thickeners, 15 filter presses, eight vacuum
belt filters, three cooling towers. In addition, off-gas scrubbers, chemical analyzers
and certain tanks, pumps, and feeders were delivered by Outotec. The delivery scope
included detail engineering, manufacturing, and erection supervision, whereas the
construction activities were carried out by other contractors. Figure 2 shows two
photographs of the installed equipment.
Along with completing installations, wet commissioning activities started gradually during 2018. These included water tests, instrument and loop testing, calibrations, field training, etc. The leaching and purification process areas were started up
late 2018 and ramped up towards nominal production during the first half of 2019.
Outotec was present with mechanical, process, and automation support at the plant
during the start-up and ramp-up periods.
369
(2) cobalt, nickel, and cadmium removal, and (3) polishing. All steps utilize zinc
powder for the cementation reaction, whereas antimony trioxide is added as activator to the second stage for efficient cobalt removal. To control the chloride leached
from concentrates, a chloride removal step is integrated to the new solution purification plant. The chloride removal is based on Outotec technology utilizing cuprous
oxide formed in the copper removal step. After the polishing stage, there is a gypsum
removal step for lowering the Ca concentration in solution by cooling and precipitation [3]. The last step in the expanded process is a new zinc electrowinning plant. The
zinc cathodes from the new electrowinning are transported to the Aleazin facility of
Peñoles for melting and casting.
Some nominal flow figures are given for reference: The concentrate feed to DL
is around 31 ton/h of dry mass, and the total flow to solution purification is around
450 m
3 /h. The calcine feed, being approx. 53 ton/h, was not affected by the expansion.
Implementation
Peñoles consulted Outotec for the conceptual and basic engineering of the total leaching and solution purification expansion. Leaching tests both in batch and continuous
mode with several concentrates of Peñoles proved the suitability of DL and formed
the basis for the design. Several stages of conceptual process engineering were executed, focusing mainly on how to integrate the new sections optimally in the existing
plant. The basic engineering including process, equipment, layout, piping, electrification, instrumentation, and automation design provided data for cost calculations
and offers, leading finally to the investment decision by Peñoles.
All the key process equipment of the new leaching and purification areas were in
Outotec delivery scope; 57 reactors, five thickeners, 15 filter presses, eight vacuum
belt filters, three cooling towers. In addition, off-gas scrubbers, chemical analyzers
and certain tanks, pumps, and feeders were delivered by Outotec. The delivery scope
included detail engineering, manufacturing, and erection supervision, whereas the
construction activities were carried out by other contractors. Figure 2 shows two
photographs of the installed equipment.
Along with completing installations, wet commissioning activities started gradually during 2018. These included water tests, instrument and loop testing, calibrations, field training, etc. The leaching and purification process areas were started up
late 2018 and ramped up towards nominal production during the first half of 2019.
Outotec was present with mechanical, process, and automation support at the plant
during the start-up and ramp-up periods.