This project is about the design of a
Hydrometallurgical Copper Processing Plant
mainly for small scale miners.
The project looks at a paradigm shift from the
conventional large scale processing of copper to
small scale processing of copper affordable to local
The plant to be designed will be able to
process 15 metric tonnes of copper ore per
day with 80% recovery. It will be economical,
cost effective and affordable for average local
The project was aimed at designing a
Hydrometallurgical Copper Processing
Plant on a small scale that would process
about 15 tons of copper oxide ore per day
and recover over 80% of copper.
6. SPECIFIC OBJECTIVES
1. To establish the most economical
hydrometallurgical technique for the treatment of
2. To carry out theoretical material balances of the
plant and to establish the feed rate required.
3. To carry out an energy balance of the
hydrometallurgical plant and establish the power
required to operate the plant.
4. To determine the types and sizes of the equipment
5. To determine the capital cost of the plant.
Part of the design work was based on the
laboratory experiments and the other part was
The work was divided in the following phases:
9. Process design
The work in this stage involved;
• Determination of the appropriate feed rate
for a small scale plant.
• The theoretical material and energy
balances of the overall plant and the
• Recovery, plant attainment and overall
10. Mechanical design
The work involved in this stage included;
• Selection of appropriate equipment.
• Sizing of the equipment
• Selecting the appropriate materials of
construction to be used.
12. Project costing
• Cost of different equipment was obtained
from reliable internet vendors.
• The material costs for the equipment
fabricated on sight was also obtained
from the internet. 40% was added for
14. Summary of material and energy
INPUT OUTPUT EFFICIENCY
Cu ore 1.5t/h (6wt%) 1.34t/h
Fresh water 35m3/hr 0 100%(assuming
Sulphuric acid 1.6m3/hr 0.029m3/hr 98.2%
17m3 0 100% (recycle of
112kW - -
Inlet Size (mm) 150×250
Maximum feeding size (mm) 125
Adjusting range of size (mm) 15-45
Capacity (t/h) 1.2-3.5
Motor (KW) 5.5
Weight (t) 0.8
Overall dimensions (L×W×H) (mm)
FOB Price (USD) 1650.00
Table 4.1 jaw crusher specifications
19. Table 4.5 thickener design results
Diameter of thickener 10.0m
Height of cylindrical section 2.0m
Surface area of cylindrical section (m2) 62.8 63
Outlet diameter 1.0m
Volume of the cone 65.4m3
Surface area of the cone 25.868m2
Volume of the cylindrical section 157.1m3
Total surface are of thickener (m2) 90
Power requirement (kW) 0.12
Material of construction of shell Carbon steel
Thickness of shell 10mm
Material of construction of lining Vulcanized Latex
Thickness of lining (mm) 20
Total volume of shell (m3) 0.9 1
Total dead weight of thickener (t) 7.9 (steel shell) +
1.92 = 9.82 10
Total cost of rubber (mass of rubber (kg) × $2.50 (usd) 5000
Total cost of steel (hot rolled plate)(mass of steel (t) × $700
Total cost of thickener shell manufacture (usd) 15000
Mass of ore (Kg) 1500
Residence time (h) 3
Diameter of leach tank (m) 2
Height of leach tank (m) 2
Power (KW) 0.2
Torque (KW/rps) 0.03
Residue acid mass (pH=2) Kg 40.58
Tank thickness (mm) 9
Plate thickness (mm) 40
Impeller diameter (mm) 700
Table 4.6 Leaching Circuit
Over flow rate (m3/h) 1.5
Under flow rate (m3/h) 2.7
Copper Concentration In Overflow (g/l) 18.1
Average area (m2) 2.2
Diameter (m) 1.7
Cone angle (°) 30
Torque (Nm) 1530.2
Gearbox output speed (rpm) 0.378
Power (KW) 0.12
Clarifier thickness (mm) 10
Rubber lining thickness (mm) 5
Settling pond volume (m3) 302
Table 4.7 Solution Purification
Concentration of copper in PLS(g/l) 18.1
Extractant LIX 984N/LIX 973N
Mixing time (min) 15
Diameter of a mixer (m) 1
Height of a mixer (m) 2
Impeller diameter (mm) 330
Separation time (min) 30
Height of settler (m) 1
Length of settler (m) 6
Breadth of settler (m) 3
Mixer Construction material Carbon steel with PVC paint coating
Settler Construction material Concrete with PVC lining
Table 4.8 Solvent Extraction
Dimensions (L × W × H)m 4.2 × 1.25 × 1.5
Cost per cell K30 000
Total cost (15 cells) K154 000
Cost per stainless steel plate K16 800
Total cost (300 stainless steel plate) K5 040 000
Cost per anode plate K56
Total cost (315 anode plates) K K17 640
Cost of rectifier
Total cost (K) K5 300 000
Cathode production (tonnes /yr.) 518
Total number 80
Construction material Polymer concrete
Length × width × depth(inside), m 4.8 × 1.25 × 1.5
Anodes, cathodes per cell 20/21
Spaces between anodes and cathodes, mm 95
Material % 98.4%Pb, 1.5%Sn, 0.08%Ca, 0.02%Al
Table 4.9 Electrowinning
24. Length × width × thickness, m 1.1 × 0.9 × 0.006
Center – to - center spacing in cell, mm 95
Life, yr. 5
Type Stainless steel
Length × width × thickness, m 1.2 × 1.0 × 0.003
Side edge strip material PVC
Bottom strip material PVC/RUBBER
Plating time, days 10
Mass Cu plated on blank, Kg 60
Stripping method Hand stripping
Power and energy
Cathode current density, A/m2
Cathode current efficiency, % 98
Cell voltage, V 1.98-2
Cell current, kilo amperes 30
Power kW 60
Cu, Kg/m3 45-55
H2SO4, Kg/m3 180-190
Temperature, °C 60-65
Out of cells
Cu, Kg/m3 40
H2SO4, Kg/m3 200
Temperature, °C 65
Addition rates, g/per tonne of cathode
Guar gum, ppm 250
Cobalt sulfate, ppm< 150
Chloride ions, ppm < 30
Electrolyte treatments before entering
Gamet / anthracite filtration, heat exchanger
26. Site location
• The overriding factor when selecting the
site for this plant was the proximity to the
main raw material- copper oxide ores.
• Other factors considered included source
of electricity, water and proximity to acid
• Areas suitable for this plant include
Kasempa, Mufumbwe and Mumbwa
Wet grinding was employed in this plant to reduce
energy usage, facilitate removal of material and to
Three hydrocyclones were used to increase efficiency of
the plant and also to allow room for expansion of the
The thickener serves two purposes; allows the slurry to
be of required density for optimum extraction during
leaching and serves as a recycle line for the water to
minimize fresh water usage.
pH was maintained between 1.8-2 to ensure proper extraction
of copper in the leach tank.
Four tanks in parallel were used to achieve a continuous
Solid-Liquid Separation Circuit
The separation of solids from the metal laden liquid was the
most difficult separation process to achieve. In the lab, the
separation was effectively using a leaf filter and the washing
done using hot water.
However, on a commercial scale, the raffinate will be used to
wash the gangue solids
The thickener will employed to facilitate the continuous
separation of solids from the metal laden liquid.
Solvent Extraction Circuit
The circuit is made up of 2 extraction stages and 1-
The PVC material will be used for lining the settler which
will be made of concrete.
The number of cathodes was determined for a 10 days
standard for electroplating 60 kg of copper on each
cathode to be 22 per cell.
Polymer concrete cells were used.
The total cost of the plant was determined to be $1.1
million (K5.8million). Adding 40% for installation, civil
works and electrical works the total comes to about $1.5
million dollars (K8.5 million).
A material balances and energy balances of the plant was
conducted and the plant was determined to have an
efficiency of at least 90%. The feed rate for the copper ore
was determined to be 1.5 tonnes per hour. The power
requirements of the plant was about 120kW (costing the
plant K2000/day on energy). The total copper output of the
plant is about 1,900kg copper per day giving an annual
output of 583 tonnes.
The capital cost of the plant was determined to be
$1.5million dollars (K8.5 million).
Small scale hydrometallurgical processing is a very viable
project for a developing country like Zambia. It will enable
empowerment of Zambians in an industry dominated by
foreign multinational companies.
Small scale hydrometallurgical processing is a very
viable project. And This can easily be achieved if a team
of different specialists come together to start the plant.
The use of plant design software will help optimize the
plant more accurately.
The structural and mechanical design of the plant should
be carried out by more specialized structural and
Other areas which require specialists include
instrumentation, civil works, electrical works and detailed
1. Brownell, L.E., and Young, E.H. (1959) Process Equipment Design,
New York, John Wiley and Sons, Inc.
2. Chiranjib, K.G. (2003) Chemical Metallurgy, (1sted), Mumbai, India:
John Wiley publishers.
3. Davenport W.G. (2002) extractive metallurgy of copper, (4thed),
university of Missouri, USA.
4. Greenwood, N.N. and Earnshaw, A. (1984) Chemistry of the
Elements, (2nded), U.K., Reed Education and Profession Publishing
5. Kolthoff, Sandell, and Meehan. (1969) Quantitative Chemical Analysis,
(4th edition), U.S.A, The MacMillan Company.
6. Mark, E. eta’l (2004) Extractive Metallurgy of copper, (5thed),
Amsterdam, Netherlands: Elsevier.
7. Martin, R. (2008) Introduction to particle technology, (2nd edition),
Monash university, Australia: John Wiley & sons.
8. Max, S.P., and Klaus D.T. (1991)Plant Design and Economics for
Chemical Engineers, (4thed),New York St. Louis, McGraw-Hill, Inc.
9. McCabe, W.L., Smith, J.C., and Harriott, P., (1987) Unit Operations of
Chemical Engineering, (4thed), Singapore, McGraw-Hill Book Company.
10.Pierce, Haenisch, and Sawyer. (1958) Quantitative Analysis, (4thed),
U.S.A., John Wiley and Sons, Inc.
11.Sinnot, R.K. (2005) Chemical Engineering Design, (volume 6), London,
Elsevier Butterworth Heinemann
12.Speight, J.G. (2002) Chemical and Process Design Handbook, New
York, McGraw - Hill.
13.Steve, M. (2004) The IDC Engineers pocket Guide, (5th edition), West
Perth, Australia: IDC Technologies
14.Strouts, C.R., Wilson, H.N., and Parry, R.T. (1967) Chemical Analysis,
(Vol. 2), U.K., Oxford University Press.
15.Swift, E.N. (1972) Quantitative Measurements and Chemical Equilibria,
USA, W.H. Freeman and Company.