Metallurgical plants require a wide range of specialized pumps beyond standard centrifugal and slurry types — from high-pressure descaling pumps to magnetic drive chemical pumps, from vertical sump pumps to peristaltic hose pumps for sludge. Selecting the right pump type for each application is critical for reliability, safety, and total cost of ownership. This guide covers special pump types and their selection criteria for metallurgical applications.
Pump Type Overview for Metallurgy
| Pump Type | Flow Range | Head Range | Best For | Limitations |
|---|---|---|---|---|
| API 610 process pump | 5-500 m³/h | 20-300m | Refinery, hydrocarbon, acid | Not for slurry |
| Horizontal slurry pump | 20-2000 m³/h | 10-80m | Ore, tailings, FGD | Low efficiency, wear |
| Vertical sump pump | 5-500 m³/h | 5-50m | Pits, sumps, wastewater | Shaft length limit |
| Magnetic drive pump | 1-100 m³/h | 5-80m | Acid, toxic, zero leakage | No dry run, no slurry |
| Fluoroplastic pump | 1-200 m³/h | 5-60m | Strong acid, corrosive | Temp < 150°C |
| Multistage centrifugal | 5-500 m³/h | 50-2000m | Boiler feed, descaling, RO | Complex, high cost |
| Peristaltic hose pump | 0.1-100 m³/h | 5-20m | Sludge, filter feed, dosing | Pulsating, hose wear |
| Diaphragm metering pump | 0.001-10 m³/h | 10-200m | Chemical dosing, precise | Low flow, pulsating |
| Gear pump (internal) | 0.5-50 m³/h | 10-100m | Oil, viscous, lubricating | Not for abrasive |
| Screw pump | 1-200 m³/h | 10-100m | Viscous, multiphase | Not for abrasive |
| Self-priming pump | 5-300 m³/h | 5-50m | Sumps, transfer, drainage | Limited suction lift |
| High-temp pump | 5-300 m³/h | 20-150m | Thermal oil, hot acid | Special materials, cooling |
Selection by Application
1. Acid and Corrosive Chemicals
- Strong acid (HCl, H₂SO₄ dilute hot): Fluoroplastic pump (PTFE/PFA lined) or magnetic drive pump. Zero leakage, excellent corrosion resistance.
- Concentrated H₂SO₄ (>90%): Cast iron or high-silicon iron pump. Passivates in concentrated acid.
- HF (hydrofluoric): Monel or PTFE lined magnetic drive. Never use glass/ceramic.
- Toxic (cyanide): Magnetic drive or double mechanical seal (Plan 53B). Zero leakage mandatory.
- High chloride (FGD water): Duplex or super duplex stainless pump. 316SS pits in high chloride.
2. Slurry and Solids-Laden Fluids
- Ore/tailings (high abrasion): Horizontal slurry pump with rubber-lined casing and 27% Cr impeller.
- Sumps/pits (slurry): Vertical sump pump — submerged impeller, no priming.
- Filter feed (high solids, variable): Peristaltic hose pump — handles high solids, variable flow, no seal.
- Fine slurry (FGD): Rubber-lined slurry pump with expeller seal.
- Acidic slurry (pickling): Rubber-lined or duplex slurry pump — corrosion + abrasion.
3. High-Pressure Applications
- Descaling (150-250 bar): Horizontal multistage ring-section pump. 6-10 stages, 500-5000 kW.
- Boiler feed (10-200 bar): Multistage centrifugal pump or horizontal multistage boiler feed pump. Hot water, NPSH critical.
- RO feed (15-80 bar): Vertical or horizontal multistage. Duplex for seawater.
- Chemical injection (high pressure): Diaphragm metering pump — precise, high pressure.
4. High-Temperature Applications
- Thermal oil (150-350°C): API 610 hot oil pump, centerline support, Plan 23 seal cooling.
- Hot acid (50-90°C): High-temperature chemical pump or high-temp sulfuric acid pump. PTFE lined or high-silicon iron.
- Hot caustic (100-280°C): Duplex or super duplex multistage. Plan 23 seal cooling.
- Jacketed (crystallizing): Steam or electric jacketed pump. Preheat before startup.
5. Self-Priming and Drainage
- Process water sumps: Stainless steel self-priming pump. Automatic priming.
- Acid transfer (above tank): Fluoroplastic self-priming pump or fluorine-lined self-priming pump.
- Stormwater/drainage: Self-priming trash pump with large passages.
- Deep pits: Vertical sump or submersible — better than self-priming for deep lift.
6. Viscous and Oily Fluids
- Lubricating oil, hydraulic oil: Internal gear pump — smooth flow, handles viscosity.
- High viscosity (molasses, pitch): Screw pump or progressive cavity pump. Jacketed for heating.
- Fuel oil, diesel: Gear pump or screw pump. Explosion-proof motor.
- Multiphase (oil + gas): Screw pump (twin screw). Handles gas entrainment.
7. Chemical Dosing and Metering
- Acid/base dosing: Diaphragm metering pump. ±1% accuracy, PVDF/PTFE wetted parts.
- Flocculant/polymer: Peristaltic hose pump or progressive cavity. Handles shear-sensitive fluids.
- Solvent dosing: Gear pump or diaphragm metering. Explosion-proof.
- High-pressure injection: Plunger pump or high-pressure diaphragm metering.
Selection Decision Framework
Step 1: Define Fluid Properties
- Composition and concentration
- Temperature and pressure
- Specific gravity and viscosity
- Solids content and particle size
- Vapor pressure (for NPSH)
- Hazard classification (toxic, flammable, corrosive)
Step 2: Define Operating Conditions
- Required flow rate (normal and maximum)
- Required head or discharge pressure
- Suction conditions (flooded, lift, NPSH available)
- Operating hours and duty cycle
- Flow variability (constant, intermittent, variable)
Step 3: Select Pump Type
| If fluid is... | Consider... |
|---|---|
| Clean, low viscosity, non-hazardous | Standard centrifugal (end suction, split case) |
| Corrosive (acid, caustic) | Fluoroplastic, magnetic drive, duplex stainless |
| Toxic/hazardous | Magnetic drive, double mechanical seal |
| Slurry/solids | Slurry pump, vertical sump, peristaltic |
| High pressure (>20 bar) | Multistage centrifugal, PD pump |
| High temperature (>150°C) | API 610 hot oil, jacketed, high-temp magnetic |
| Viscous (>500 cSt) | Gear, screw, progressive cavity |
| Precise dosing | Diaphragm metering, peristaltic |
| Above fluid source | Self-priming, vertical sump, submersible |
Step 4: Select Materials
- Verify material compatibility with exact fluid composition, concentration, and temperature
- For slurry: rubber-lined (fine) or 27% Cr (coarse)
- For acid: PTFE/PFA lined, Hastelloy, high-silicon iron
- For high chloride: duplex or super duplex
- Require material test reports (MTR) for critical applications
Step 5: Select Seal and Auxiliaries
- Clean, non-hazardous: single mechanical seal
- Toxic/hazardous: magnetic drive or double seal (Plan 53B)
- Slurry: expeller seal or mechanical + Plan 32 flush
- Hot fluid: Plan 23 (recirculation with cooler)
- Include seal support system in scope
Common Selection Mistakes
- Using standard centrifugal for slurry: Rapid wear, clogging. Use slurry pump.
- Using 316SS for hot dilute H₂SO₄: Rapid corrosion. Use PTFE/Hastelloy.
- Using magnetic drive for slurry: Bearing wear in months. Use slurry pump with seal.
- Oversizing pumps: Operates off-BEP, wastes energy, causes cavitation. Size for actual requirements.
- Ignoring NPSH for hot fluids: Cavitation damage. Calculate NPSH available, maintain margin.
- Using single seal for toxic fluid: Safety hazard, environmental non-compliance. Use double seal or magnetic drive.
- Ignoring suction conditions: Air entrainment, cavitation, poor priming. Design suction properly.
- Not considering total cost of ownership: Cheap pump has high maintenance/energy cost. Evaluate TCO.
Procurement Recommendations
- Provide complete fluid analysis and operating conditions
- Specify pump type per application (don't accept substitutions without review)
- Require material test reports for wetted components
- Specify seal plan per API 682 for critical pumps
- Include spare parts: rotating assembly, seals, bearings, wear parts
- Require factory performance test (witnessed for critical pumps)
- Verify supplier has metallurgical industry references
- For slurry: require wear life guarantee
- For toxic/hazardous: require zero-leakage design and leak detection
- Specify baseplate, instrumentation, and seal support system in scope
- Consider total cost of ownership, not just purchase price
- Require installation, operation, and maintenance manuals
Related Industries
Special pump selection principles apply to all process industries: oil and gas (API 610, multiphase), chemical manufacturing (magnetic drive, fluoroplastic), pharmaceutical (sanitary, metering), food and beverage (sanitary PD), power generation (boiler feed, FGD), and water treatment (metering, sludge). The core principle — match pump type, material, and seal to fluid properties and operating conditions — is consistent across industries.