Copper Leaching Defoamer: Expert Foam Control Solutions for Hydrometallurgy

In the evolving landscape of hydrometallurgical copper recovery, leaching technology has emerged as a critical method for extracting copper from low-grade ores and oxide resources. However, one increasingly prominent operational challenge is persistent foam formation during the leaching process. This foam, although not generated by traditional foaming agents, can severely affect equipment performance, copper recovery rates, and operational safety.

This expert-level guide provides a comprehensive overview of copper leaching defoamer selection, performance criteria, and application strategies—empowering operators to manage foam effectively and ensure consistent process stability.

Copper Leaching Defoamer

Why Foam Control Matters in Copper Leaching?

What is Copper Leaching?

Copper leaching is a hydrometallurgical process where copper is dissolved from ore into solution using acidic lixiviants such as sulfuric acid. Depending on the ore type and operation design, common methods include:

  • Heap Leaching – for large-particle ores, involving acid spray over ore piles;

  • Agitated Leaching – for fine-particle ores, using mechanical mixing;

  • In-situ Leaching – injecting lixiviants directly into the ore body underground.

Following leaching, the copper-rich pregnant leach solution (PLS) is processed via Solvent Extraction and Electrowinning (SX-EW) to recover pure copper.

Where Does the Foam Come From?

Though no foaming agents are added deliberately, foam becomes problematic due to the following factors:

  • Strong acid environment (pH 1–3): increases solution viscosity and surface tension;

  • High ionic strength: ions like Cu²⁺, Fe³⁺, SO₄²⁻, and Cl⁻ stabilize foam;

  • Air entrainment: from agitation, pumping, or spraying operations;

  • Surface-active impurities: residual flotation agents, ore fines, and oils;

  • Foam accumulation: due to recycling of pregnant solutions without foam dissipation.

The Impact of Foam on Copper Leaching Operations

Operational Hazards and Efficiency Losses

  • Overflow risks: foam accumulation can lead to tank spills or pipeline blockages;

  • Process disruption: excessive foam interferes with flow control and sensor accuracy;

  • Copper losses: foam carries valuable copper ions, reducing overall yield;

  • SX-EW interference: foam may destabilize phase separation in solvent extraction, impacting final purity;

  • Increased maintenance: cleaning and downtime caused by foam-related issues.

Thus, implementing a reliable copper leaching defoamer becomes essential to maintain safe, efficient, and profitable operations.

Key Performance Criteria for Copper Leaching Defoamers

An effective defoamer for copper leaching must withstand extreme conditions and remain compatible with downstream processes. The six core performance attributes include:

Attribute Description
Acid Resistance Stable in pH 1–3; no decomposition or phase separation
Oxidation Stability Withstands oxidative species like Fe³⁺ and Cl⁻
Rapid Foam Knockdown Breaks foam instantly under high agitation and air entrainment
Long-Lasting Suppression Prevents reformation of foam for 4–8 hours or more
SX-EW Compatibility Does not chelate copper ions or interfere with solvent extraction
Water Dispersibility Easily emulsifies or disperses in aqueous systems; no sedimentation

Recommended Types of Copper Leaching Defoamers

1. Modified Polyether-Based Defoamers (Silicone-Free)

  • Composition: EO/PO block copolymers, often end-capped for acid resistance

  • Advantages:

  1. Excellent compatibility with acidic environments
  2. Fast defoaming action
  3. Non-silicone: ideal for SX-EW systems

  • Use Cases: Pregnant leach solutions (PLS), agitation tanks, recirculation loops

Polyether-Modified Silicone Defoamers

  • Composition: Silicone oils grafted with polyether chains, plus hydrophobic silica
  • Advantages:
  1. Powerful and durable defoaming and anti-foaming action
  2. Ideal for persistent, surface foam
  • Use Cases: Foam overflow control, PLS storage tanks, acid wash loops

Powdered Defoamer Formulations

  • Composition: Polyether defoamer absorbed on inorganic carriers like silicates
  • Advantages:

    1. Solid form for easy storage and transport

    2. Suitable for pre-treatment stages

  • Use Cases: Heap leaching ore pre-wetting, dry blending with ore before stacking

Application Strategies for Maximum Defoaming Efficiency

To ensure optimal performance and cost-efficiency, copper leaching defoamers should be applied based on process locations and foam severity:

Application Area Method Suggested Dosage & Notes
Spray Irrigation Inline Liquid Dosing 30–50 ppm continuous dosing via metering pump
PLS Tanks Drip Addition 0.1–0.3 L per hour, adjusted by foam observation
Ore Pre-treatment Dry Mixing / Spraying 1–2 kg per ton of ore, use powdered defoamer if applicable

Pro tip: Use foam height sensors or manual checks to optimize dosage and avoid overdosing, which can lead to reduced process reactivity (“defoamer poisoning”).

Your Expert Solution for Copper Leaching Foam Control

Foam control in copper leaching is not a secondary issue—it’s a critical component of operational stability and profitability. By selecting a well-formulated, acid-resistant copper leaching defoamer, you can reduce process disruptions, protect downstream SX-EW operations, and enhance copper recovery.

Whether you’re managing heap leaching, stirred tank systems, or in-situ recovery, the right defoamer strategy makes all the difference. At INVINO,  we offer a full portfolio of defoamer. 

Looking for a  defoamer solution tailored to your site conditions?
Contact our technical team today for expert consultation, sample requests, or on-site foam control programs.

Q&A: Optimizing the SX-EW Process

Q: Will the defoamer increase the phase separation time in SX settlers?
No. This is the most critical parameter. Our specialized metallurgical grade is formulated to break foam without acting as an emulsifier. It has been tested to ensure it does not increase the "Phase Disengagement Time" (PDT), ensuring the organic and aqueous phases separate rapidly and cleanly.
Q: Is it compatible with common extractants (e.g., LIX, Acorga)?
Yes. We understand that the extractant (oxime) is the most expensive chemical in your circuit. Our defoamers are chemically inert towards phenolic oximes and do not cause degradation or loss of extraction efficiency (loading capacity).
Q: Can it help reduce organic entrainment losses?
Yes. Foam at the settler interface often traps organic droplets, leading to expensive solvent loss into the raffinate. By eliminating this "Crud" layer (interfacial sludge), our defoamer helps recover the organic phase and reduces the organic load sent to the electrowinning tank.
Q: Will it cause "burning" or contamination of the Copper Cathode?
No. Any chemical entering the Electrowinning (EW) cell must be non-contaminating. Our product is designed to be stable in the electrolyte and does not deposit on the cathode surface, ensuring you maintain LME Grade A purity without "sticky stripping" issues.
Q: Is it stable in strong Sulfuric Acid leaching solutions?
Absolutely. The leaching solution (PLS) is highly acidic (pH < 2). Our defoamer is engineered with an acid-resistant molecular structure that prevents hydrolysis, ensuring consistent performance from the agitation leach tanks through to the thickeners.