Iron ore and copper ore processing involves pumping highly abrasive slurries through grinding, classification, flotation, thickening, and tailings circuits. These operations require slurry pumps that can handle high solids concentrations, coarse particles, and corrosive process chemicals. This guide covers slurry pump selection for iron ore and copper ore processing.
Ore Processing Overview
Iron Ore
- Mining: open pit (hematite, magnetite)
- Crushing: jaw/cone crusher to <150mm
- Grinding: SAG/ball mill to <150μm
- Beneficiation: magnetic separation (magnetite) or flotation
- Thickening: concentrate to 60-70% solids
- Filtering: dewater to <10% moisture
- Pelletizing (optional): produce pellets for direct reduction
- Tailings: disposal (dam or paste fill)
Copper Ore
- Mining: open pit or underground (chalcopyrite, bornite, chalcocite)
- Crushing: jaw/cone crusher
- Grinding: SAG/ball mill to <100μm (liberate copper minerals)
- Flotation: separate copper sulfide from gangue (collectors, frothers)
- Thickening: concentrate to 60-70% solids
- Filtering: dewater
- Smelting: concentrate → matte (copper sulfide + iron sulfide)
- Converting: matte → blister copper (98.5% Cu)
- Electrorefining: blister → cathode (99.99% Cu)
- Tailings: disposal
Slurry Applications
| Application | Solids % | SG | Abrasion | Corrosion | Particle Size |
|---|---|---|---|---|---|
| Grinding circuit | 30-60% | 1.5-2.0 | Very high | Low | <150μm |
| Cyclone feed | 30-50% | 1.5-1.9 | Very high | Low | <150μm |
| Flotation feed | 30-40% | 1.4-1.7 | High | Moderate (reagents) | <100μm |
| Concentrate | 50-70% | 1.8-2.5 | High | Moderate | <75μm |
| Tailings | 30-60% | 1.4-1.8 | Very high | Low | <150μm |
| Paste fill | 60-80% | 1.8-2.2 | Very high | Low | <150μm |
| Acid leach (copper) | 20-40% | 1.3-1.6 | High | Very high | <150μm |
| Scrubber (SO2) | 10-30% | 1.1-1.3 | Moderate | High (acid) | <100μm |
Pump Type Selection
Horizontal Centrifugal Slurry Pump
- Most common for grinding, cyclone feed, tailings (high abrasion, large flow)
- Flow: 100-30,000 m³/h, head: 30-200 m
- Large passages, thick volute, hard metal or rubber-lined
- Material: high-chrome iron (HCCI), Ni-hard, or rubber-lined
- Advantages: high flow, handles large solids, replaceable wear parts
- Iron ore: high SG (1.5-2.0) requires robust design
Vertical Slurry Pump
- For sumps, tanks, flotation cells, tailings ponds
- Flow: 50-10,000 m³/h, head: 20-100 m
- Submerged or semi-submerged, no priming
- Material: HCCI, rubber-lined, or 316 (acid)
- Advantages: handles variable level, no priming, compact
Positive Displacement (PD) Pump
- For paste fill and high-solids concentrate (high viscosity, high pressure)
- Types: piston, peristaltic, progressive cavity
- Flow: 10-300 m³/h, pressure: 20-200 bar
- For paste fill: piston pump (underground placement)
- Advantages: handles high viscosity, high pressure, consistent flow
Chemical Process Pump
- For acid leach, scrubber slurry, reagent (corrosive, low-medium solids)
- Flow: 10-500 m³/h, head: 20-150 m
- Material: 316, duplex, or fluoroplastic-lined
- Seal: mechanical with flush or magnetic drive
Material Selection
Wetted Parts
| Service | Casing | Impeller | Shaft | Seal |
|---|---|---|---|---|
| Grinding/cyclone | HCCI/rubber | HCCI | 4140/316 | Expeller/packing |
| Flotation | HCCI/rubber | HCCI | 4140/316 | Expeller/packing |
| Concentrate | HCCI/rubber | HCCI | 4140 | Expeller/mechanical |
| Tailings | HCCI/rubber | HCCI | 4140 | Expeller/packing |
| Paste fill | HCCI/steel | HCCI | 4140 | Packing/PD |
| Acid leach | 316/PTFE/rubber | 316/HCCI | 316 | Double mechanical |
| Scrubber | 316/rubber | 316 | 316 | Mechanical |
Abrasion Resistance
- Iron ore: high silica, hematite (hard, abrasive)
- Copper ore: pyrite, silica, chalcopyrite (abrasive)
- High SG (1.5-2.0) increases impact and wear
- Wear rate ∝ velocity³ — keep velocity low (1.5-3 m/s)
- Material: HCCI for coarse/hard solids, rubber for fine solids
- Iron ore plants: pump wear is a major operating cost
Corrosion Considerations
- Flotation reagents: mild corrosion (xanthates, frothers)
- Acid leach (copper oxide): sulfuric acid (highly corrosive)
- Scrubber (smelter): sulfuric acid, SO2 (corrosive)
- For acid: use 316, duplex, Hastelloy, or fluoroplastic
- Verify material compatibility with actual chemistry and temp
Design Considerations
High SG Slurry
- Iron ore concentrate: SG 1.8-2.5 (very heavy)
- Copper concentrate: SG 1.8-2.2
- High SG increases: pump power, bearing load, shaft stress, piping weight
- Pump: robust design, heavy-duty bearings, large shaft
- Motor: oversized for high SG (power ∝ SG)
- Piping: heavy supports, thick wall (wear + weight)
Grinding Circuit Pumps
- Cyclone feed pump: high flow, medium head, very abrasive
- Material: HCCI or rubber-lined
- Multiple pumps in parallel (match mill capacity)
- VFD: optimize cyclone pressure and classification
- Key: reliability, abrasion resistance, easy maintenance
- Iron ore: large mills (20+ MW) require large pumps
Flotation Pumps
- Flotation feed: moderate abrasion, reagents (mild corrosion)
- Material: HCCI or rubber-lined
- Key: handle air (from flotation), avoid shear (froth)
- Use gas-handling impeller (if air entrainment)
- Maintain velocity above deposition
Concentrate and Tailings
- Concentrate: high SG, high solids, abrasive
- Pump: horizontal slurry pump or PD
- Tailings: large flow, abrasive, lower SG
- Pump: horizontal or vertical slurry pump
- For paste fill: PD pump (piston) for underground placement
- Key: handle high solids, reliable, transport to filter or disposal
System Design
Pump Stations
- Multiple pumps in parallel (N+1 redundancy)
- Suction tank: large, agitated (prevent settling)
- Booster stations: for long tailings pipelines
- Instrumentation: flow, pressure, density, level, vibration
- VFD: optimize speed for variable flow and cyclone pressure
Piping
- Large diameter: minimize velocity (1.5-3 m/s)
- Material: rubber-lined steel, HDPE, or thick-walled steel
- Long radius elbows: reduce wear and blockage
- Slope: for drainability (flush on shutdown)
- For high SG: heavy supports, thick wall
- For tailings: rotatable pipe (even wear)
Common Issues
- Excessive wear: High silica/hard ore, high velocity. Use HCCI/rubber, lower velocity, replaceable parts.
- High SG power: Iron/copper concentrate is heavy. Oversize motor, heavy-duty pump, verify power.
- Settling/blockage: High SG, high solids. Maintain velocity, agitate tanks, flush, large passages.
- Acid corrosion: Acid leach, scrubber. Use 316/duplex/PTFE, verify compatibility, double seal.
- Bearing failure: High SG load, misalignment. Use heavy-duty bearings, align, monitor temp/vibration.
- Seal failure: Abrasive/corrosive slurry. Use expeller/double seal, proper flush, monitor.
- Tailings pipeline wear: High velocity, abrasive. Use rubber-lined/HDPE, lower velocity, rotate pipe.
- Paste fill blockage: High solids, long pipeline. Use PD pump, proper gradation, flush.
Procurement Recommendations
- Provide: ore type, hardness, SG, solids %, particle size, chemistry, flow, head
- For grinding/cyclone/tailings: specify horizontal slurry pump, HCCI or rubber-lined
- For high SG concentrate: specify heavy-duty pump, oversize motor
- For flotation: specify HCCI/rubber-lined pump, gas-handling if needed
- For acid leach: specify fluoroplastic or 316/duplex pump
- For paste fill: specify PD pump (piston/peristaltic)
- For sumps: specify vertical slurry pump
- Specify material per abrasion/corrosion (HCCI, rubber, 316, duplex, PTFE)
- Include replaceable wear parts (impeller, volute, throatbush, wear plate)
- Include instrumentation: flow, pressure, density, vibration
- For high SG: specify heavy-duty bearings and shaft
- Require wear life data from supplier
- Verify supplier has iron/copper mining references
Related Industries
Ore processing slurry pump principles apply to other mining (gold, coal, mineral sands, bauxite), oil and gas (drilling mud), power generation (ash, FGD), chemical processing (corrosive slurry), and wastewater (sludge). The core principle — reliable handling of high-SG abrasive solids-laden fluid with proper materials, wear parts, and heavy-duty design — is consistent across ore processing applications.