Lead Metal Production at Paroo Station Mine Using …
155
outcomes of the test work program in shaping the final DFS flowsheet include the
following:
• Changes to the flotation regime to increase overall Pb recoveries from ore to
concentrate;
• Inclusion of a flotation columns to limit slimes entrainment and ensure fast filtration and efficient washing of the concentrate prior to introduction into the
hydrometallurgical facility;
• Inclusion of a concentrate drying step to overcome frothing issues during the MSA
leach;
• Significant variations in mineralogy between variability samples (% Pb in cerrusite
ranged between 59 and 90%) resulting in overall predicted lead recoveries from
the variability concentrates of 96–99% (Average 98%);
• Introduction of a vacuum degassing step after MSA leach to overcome issues with
settling
• Replacing MSA filters with CCD’s to ensure good washing efficiency;
• Replacing DeS leach residue filtration with flotation to recover Pb minerals and discard gangue to tailings and reintroduction of the DeS Residue flotation concentrate
to the concentrate thickener;
• Optimization of electrowinning performance based on bench scale testing at
University of British Columbia, by increasing current density to 400 A/m
2 and
optimizing smoothing agent regime and dosing rates; and
• Demonstration of electrowinning on pilot scale and casting of ingots for lead ingot
analyses.
The Demonstration Plant operation provided additional confidence on all aspects
of the design. A total of 35.5 t of ore was prepared and floated to make 2.95 t of
concentrate with 958 kg of lead metal recovered by electrowinning.
In addition, corrosion coupon testing, optimization of desulfurization and acid
leach, boiling point elevation, flotation of galena and sulfur and further studies of
smoothing agents were investigated.
Three Metsim models comprising a base, and minimum and maximum anglesite
cases have been developed by SNC-L. The models have been used to generate heat
and mass balances required to size the equipment. Process design criteria have been
developed by SNC-L from a combination of test work results and SNC-L experience
with similar processing plants. Test work data from the completed programs has been
used in the models and other engineering data to verify the equipment selected.
The recovery of lead from concentrate to final ingot has been estimated for the
various annual composites using test results, mineralogical analyses, and the Metsim
model. An average recovery of 98% is expected across the range of ores to be treated.
The hydrometallurgical facility includes:
• Feed Preparation, Leaching and solid/liquid separation
• Impurity removal and electrolyte preparation
• Lead electrowinning
• Bleed treatment
155
outcomes of the test work program in shaping the final DFS flowsheet include the
following:
• Changes to the flotation regime to increase overall Pb recoveries from ore to
concentrate;
• Inclusion of a flotation columns to limit slimes entrainment and ensure fast filtration and efficient washing of the concentrate prior to introduction into the
hydrometallurgical facility;
• Inclusion of a concentrate drying step to overcome frothing issues during the MSA
leach;
• Significant variations in mineralogy between variability samples (% Pb in cerrusite
ranged between 59 and 90%) resulting in overall predicted lead recoveries from
the variability concentrates of 96–99% (Average 98%);
• Introduction of a vacuum degassing step after MSA leach to overcome issues with
settling
• Replacing MSA filters with CCD’s to ensure good washing efficiency;
• Replacing DeS leach residue filtration with flotation to recover Pb minerals and discard gangue to tailings and reintroduction of the DeS Residue flotation concentrate
to the concentrate thickener;
• Optimization of electrowinning performance based on bench scale testing at
University of British Columbia, by increasing current density to 400 A/m
2 and
optimizing smoothing agent regime and dosing rates; and
• Demonstration of electrowinning on pilot scale and casting of ingots for lead ingot
analyses.
The Demonstration Plant operation provided additional confidence on all aspects
of the design. A total of 35.5 t of ore was prepared and floated to make 2.95 t of
concentrate with 958 kg of lead metal recovered by electrowinning.
In addition, corrosion coupon testing, optimization of desulfurization and acid
leach, boiling point elevation, flotation of galena and sulfur and further studies of
smoothing agents were investigated.
Three Metsim models comprising a base, and minimum and maximum anglesite
cases have been developed by SNC-L. The models have been used to generate heat
and mass balances required to size the equipment. Process design criteria have been
developed by SNC-L from a combination of test work results and SNC-L experience
with similar processing plants. Test work data from the completed programs has been
used in the models and other engineering data to verify the equipment selected.
The recovery of lead from concentrate to final ingot has been estimated for the
various annual composites using test results, mineralogical analyses, and the Metsim
model. An average recovery of 98% is expected across the range of ores to be treated.
The hydrometallurgical facility includes:
• Feed Preparation, Leaching and solid/liquid separation
• Impurity removal and electrolyte preparation
• Lead electrowinning
• Bleed treatment