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A Copper SX-EW slurry pump serves the hydrometallurgical process that extracts copper from oxide ores through sulfuric acid leaching, solvent extraction with organic reagents, and electrowinning. No single pump serves all three stages. Key selection factors:
- Leaching demands wear resistance: Pregnant leach solution (PLS) carries fine ore particles in sulfuric acid. This combined abrasion and acid attack requires UHMWPE-lined or high-chrome alloy pumps that resist both erosion and corrosion.
- Solvent extraction demands zero leakage: The organic phase — kerosene-based diluent with oxime extractant — is flammable, expensive, and regulated. Sealless magnetic drive pumps or double mechanical seals are the standard for preventing fire hazard and reagent loss.
- Electrowinning demands purity: Copper-rich electrolyte must remain free of metal ion contamination. Pumps that leach iron, nickel, or chromium degrade cathode quality. Fluoroplastic-lined pumps are required for this stage.
SX-EW accounts for approximately 20% of global copper production. Plants operate continuously in remote locations where equipment reliability determines profitability. A pump failure in leaching stops production. A seal leak in solvent extraction triggers a safety incident. A contamination event in electrowinning degrades cathode purity.
After reading this guide, you will understand the pumping demands of each SX-EW stage, which materials resist acid corrosion and solids abrasion, how to specify leak-free pumps for organic phase, what purity requirements apply to EW electrolyte pumps, and which pump types deliver the lowest total cost of ownership. With over 20 years of pump manufacturing experience, Changyu Pump presents this selection guide for copper hydrometallurgy.
1. What Are the Key Stages in Copper SX-EW?
Cuivre solvent extraction-electrowinning produces high-purity copper cathode through three stages, each with distinct pumping requirements.
Leaching: Crushed copper oxide ore is irrigated with dilute acide sulfurique. The acid dissolves copper, producing PLS (1–5 g/L Cu, pH 1.5–2.0) with fine suspended ore particles. PLS pumps transfer this abrasive, acidic solution to the SX plant. After copper extraction, the depleted raffinate returns to the leach pad.
Solvent Extraction (SX): PLS contacts an organic phase — kerosene diluent with oxime extractant — that selectively binds copper. The loaded organic is stripped with highly acidic spent electrolyte (180–200 g/L H₂SO₄, 30–35 g/L Cu), producing copper-rich electrolyte for electrowinning. Three fluids require pumping: aqueous PLS/raffinate, organic phase, and rich electrolyte. The organic phase pump demands particular attention — reagents are flammable and volatile.
Electrowinning (EW): Copper-rich electrolyte flows through electrolytic cells where direct current deposits pure copper onto cathode blanks. After harvesting, depleted electrolyte returns to SX stripping.
SX-EW Fluid Characteristics
| Étape du processus | Fluide | Cuivre | Acid / Chemistry | Solides | Température |
|---|---|---|---|---|---|
| Leaching | PLS / Raffinate | 1–5 g/L | pH 1.5–2.0 H₂SO₄ | Fine ore particles | Ambient to 40°C |
| SX Extraction | Organic phase | Loaded with Cu | Kerosene + oxime | None in design; may contain crud | 25–35°C |
| SX Stripping | Rich electrolyte | 30–35 g/L | 180–200 g/L H₂SO₄ | Aucun | 35–45°C |
| EW | Electrolyte | 30–35 g/L | 180–200 g/L H₂SO₄ | Aucun | 40–50°C |
2. What Materials Are Compatible with SX-EW Fluids?
Material selection is complex because the three stages expose pumps to fundamentally different challenges.
Material Compatibility Matrix
| Matériau | PLS / Raffinate | Organic Phase | EW Electrolyte |
|---|---|---|---|
| Acier inoxydable 316L | Not recommended — rapid erosion-corrosion | Acceptable | Limited — may leach trace metals |
| Duplex 2205 | Better than 316L | Acceptable | Acceptable |
| High-Chrome (Cr27–33) | Good — excellent abrasion | Not for organic contact | Not recommended — may leach chromium |
| Doublure en UHMW-PE | Optimal — combines acid + abrasion resistance | Limited — slight swelling possible with kerosene | Not recommended — temperature limit 90°C |
| Revêtement FEP / PFA | Good — excellent acid resistance | Excellent — universal organic resistance | Excellent — zero metal leaching |
| PP | Good — economic choice | Acceptable | Acceptable — temperature limit ~80°C |
Material Selection by Stage
| Stade | Défi primaire | Matériau recommandé | Alternative |
|---|---|---|---|
| Leaching (PLS/Raffinate) | Abrasion + acid | Centrifugeuse à revêtement UHMW-PE | Alliage à haute teneur en chrome |
| SX Organic Phase | Flammable — zero leak | FEP/PFA-lined magnetic drive | 316L with double seal + ATEX/IECEx motor |
| EW Electrolyte | High purity | FEP/PFA-lined centrifugal | PVDF centrifugal |
Les ingénieurs de Changyu Pump recommandent : For PLS and raffinate, specify UHMW-PE lined centrifugal pumps as the baseline — the optimal combination of acid and abrasion resistance at copper mining cost points. For organic phase, specify sealless magnetic drive pumps with FEP/PFA lining and ATEX- or IECEx-certified motors. For EW electrolyte, specify FEP/PFA-lined pumps to prevent metal ion contamination of cathode-quality copper.
3. How to Select Pumps for the Copper SX-EW Leaching Stage?
Leaching stage pumps handle the largest flow volumes in the most demanding conditions. PLS and raffinate pumps move thousands of cubic meters daily of acidic, abrasive solution.
Leaching Pump Selection
| Type de pompe | Recommandation | Notes |
|---|---|---|
| UHMW-PE Lined Centrifugal | Primary choice | Optimal acid + abrasion resistance; replaceable liners |
| High-Chrome Alloy (Cr27–33) | Coarse solids alternative | Lower acid resistance than UHMW-PE |
| Super Duplex 2507 | Moderate abrasion, higher temp | Higher cost; requires wear plates |
| Entraînement magnétique | Intermittent PLS, zero leak | Not for high solids |
Caractéristiques principales : Size for maximum PLS flow plus 15–20% margin. Specify semi-open impellers for fine solids passage. Protect mechanical seals with external flush (1–2 bar above seal chamber, 2–5 L/min) or closed-loop barrier fluid system in arid regions.
Les ingénieurs de Changyu Pump recommandent : Specify UHMW-PE lined centrifugal pumps with semi-open impellers, seal protection system, and VFD control. The UHMW-PE lining provides the wear life for reliable operation between shutdowns.
4. How to Select Pumps for the Copper SX-EW Solvent Extraction Stage?
The SX stage presents the most diverse pumping challenges: aqueous PLS/raffinate, flammable organic phase, and highly acidic rich electrolyte.
Organic Phase Pump Requirements
Three factors drive organic phase pump specification: fire safety (kerosene is flammable), reagent value (oxime extractant is expensive), and environmental regulation (VOC emissions are restricted). Organic phase pumps must either eliminate the mechanical seal entirely or provide double mechanical seal with barrier fluid and leak detection.
SX Stage Pump Selection
| Application | Pompe recommandée | Key Specification |
|---|---|---|
| Organic phase | Sealless magnetic drive with FEP/PFA lining | ATEX/IECEx motor; PEEK containment shell |
| PLS / Raffinate | Centrifugeuse à revêtement UHMW-PE | Same as leaching stage |
| Rich electrolyte | FEP/PFA-lined centrifugal or magnetic drive | High acid resistance; no metal leaching |
Les ingénieurs de Changyu Pump recommandent : For all organic phase pumping, specify sealless magnetic drive pumps with FEP/PFA lining and ATEX- or IECEx-certified motors. The incremental cost is recovered within the first avoided organic leak.
5. How to Select Pumps for the Copper SX-EW Electrowinning Stage?
Le electrowinning stage produces the final copper product. Electrolyte circulation pumps must deliver continuous flow with absolute purity — metal ion contamination directly degrades cathode quality.
Zero metal ion leaching: Electrolyte (180–200 g/L H₂SO₄, 30–35 g/L Cu) at 40–50°C aggressively attacks standard stainless steel, leaching iron, nickel, and chromium. These ions co-deposit with copper, reducing cathode purity and market value.
Temperature considerations: FEP lining serves standard EW electrolyte at 40–50°C. For circuits where temperature excursions above 80°C are possible, upgrade to PFA lining.
EW Stage Pump Selection
| Application | Pompe recommandée | Key Specification |
|---|---|---|
| Rich electrolyte circulation | FEP/PFA-lined centrifugal | Zero metal leaching; VFD control |
| Spent electrolyte return | FEP/PFA-lined centrifugal | Same model for spare parts commonality |
| Acid mist scrubbing | PP or PVDF centrifugal | Lower cost for non-product-contact |
Les ingénieurs de Changyu Pump recommandent : For all electrolyte-contact pumps, specify FEP or PFA fluoroplastic-lined centrifugal pumps. Standard stainless steel will leach trace metals and should not be used for EW electrolyte service.
6. Changyu Pump’s Copper SX-EW Slurry Pump Solutions
Three pump series serve copper SX-EW applications:
SX-EW Pump Selection
| SX-EW Stage | Application | Série | Caractéristique principale |
|---|---|---|---|
| Leaching | PLS / Raffinate | Série UHB | UHMW-PE lined; abrasion + acid resistant |
| SX Organic Phase | Organic transfer | Série CQZ | Sealless magnetic drive; zero leak; ATEX/IECEx |
| SX / EW Electrolyte | Rich / Spent electrolyte | Série CYB-ZKJ | FEP/PFA-lined; zero metal leaching |
UHB Series — UHMW-PE Lined Pump for PLS and Raffinate
Steel-reinforced UHMW-PE lining provides optimal acid and abrasion resistance. Semi-open impeller handles fine solids. Replaceable wear liners extend casing life.
| Paramètres | Spécifications |
|---|---|
| Débit | 3-2 600 m³/h |
| Tête | 5-100 m |
| Température | De -20°C à 90°C |
CQZ Series — Magnetic Drive Pump for Organic Phase
Sealless magnetic drive eliminates mechanical seal. FEP/PFA lining resists kerosene and oxime reagents. ATEX/IECEx motors available.
| Paramètres | Spécifications |
|---|---|
| Débit | 3-800 m³/h |
| Tête | 12,5–130 m |
| Température | -120°C à 320°C |
CYB-ZKJ Series — FEP/PFA-Lined Pump for Electrolyte
Fluoroplastic lining isolates electrolyte from metal casing, preventing metal ion leaching. Universal acid resistance across full electrolyte range.
| Paramètres | Spécifications |
|---|---|
| Débit | 3-2 600 m³/h |
| Tête | 5-100 m |
| Température | De -80°C à 120°C |
7. Case Study of Copper SX-EW Slurry Pump: Solving a PLS Pump Wear Failure
A copper SX-EW plant in South America used 316L stainless steel centrifugal pumps for PLS transfer. The PLS carried 2 g/L copper in sulfuric acid at pH 1.8 with fine ore particles.
Within four months, pump casings and impellers showed severe wear. Impeller wear rings eroded, reducing flow by 30%. Mechanical seals failed every 6–8 weeks from solids intrusion. Each pump required rebuilding three times per year.
Root cause analysis confirmed that 316L had insufficient hardness to resist fine ore particle erosion. The combined erosion-corrosion mechanism made 316L uneconomical.
Changyu Pump replaced the 316L pumps with UHB Series UHMW-PE lined pumps. The UHMW-PE lining provided acid resistance equal to or exceeding 316L, with significantly superior abrasion resistance. External mechanical seal flush eliminated solids intrusion.
Two years after replacement: zero casing or impeller replacements. Mechanical seal life extended from 6–8 weeks to over 18 months. The plant standardized on UHB Series for all PLS and raffinate applications.
Key takeaway: For PLS and raffinate in copper SX-EW, stainless steel is not the optimal material. UHMW-PE lined pumps provide both chemical resistance and abrasion resistance for continuous leaching operations.
FAQs about Copper SX-EW Slurry Pumps
Q: What pump type is recommended for PLS transfer in copper SX-EW?
A: UHMW-PE lined centrifugal pumps provide the optimal combination of sulfuric acid resistance and abrasion resistance. High-chrome alloy pumps are an alternative for coarse solids.
Q: Can I use stainless steel pumps for copper SX-EW?
A: For PLS and raffinate, 316L is not recommended — combined acid and solids cause rapid erosion-corrosion. For EW electrolyte, stainless steel is not recommended due to metal ion leaching.
Q: Why are magnetic drive pumps used for SX organic phase?
A: The organic phase is flammable, expensive, and VOC-regulated. Sealless magnetic drive pumps eliminate the mechanical seal, preventing fire hazard and reagent loss.
Q: What material prevents metal ion contamination in EW electrolyte?
A: FEP or PFA fluoroplastic-lined pumps provide zero metal ion leaching, protecting cathode purity.
Q: How do I size a PLS pump for heap leach?
A: Size for maximum PLS flow plus 15–20% margin with VFD control. Install multiple pumps in parallel for larger operations.
Liste de contrôle des mesures de prévention pour les ingénieurs en pompes chez Changyu
- Do not specify 316L for PLS or raffinate — combined acid and solids erosion destroys pumps within months.
- Specify sealless magnetic drive pumps for all SX organic phase service.
- Use FEP/PFA-lined pumps for all EW electrolyte contact to protect cathode purity.
- Protect PLS pump seals with external flush or closed-loop barrier fluid system.
- Specify ATEX- or IECEx-certified motors for SX building pumps.
- Size PLS pumps with VFD control for variable flow conditions.
- Keep spare impellers, wear rings, and mechanical seals in inventory.
- Verify material compatibility with the specific organic reagent used in your plant.
Conclusion
A copper SX-EW plant depends on pumps matched to each process stage. Leaching requires UHMW-PE lined pumps that resist both acid and abrasion. Solvent extraction demands sealless magnetic drive pumps that eliminate organic leaks. Electrowinning requires fluoroplastic-lined pumps that protect cathode purity.
The cost of the wrong pump is measured in lost production, safety incidents, and degraded product value. Correct specification at each stage is an investment in reliability, safety, and copper quality.
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