Copper Leaching Process & Plant Setup for Low-Grade Ore | Hengtai

Copper Leaching Process: Highly Efficient Recovery for Low-Grade Copper Ore

The copper leaching process is a globally recognized method for processing low-grade copper ore, oxidized copper ore, or complex polymetallic ores. The core objective is to dissolve copper from the ore into a solution using chemical solvents, followed by extraction and electrodeposition to produce high-purity cathode copper.

Depending on the ore characteristics, common leaching methods include heap leaching, vat leaching, in-situ leaching, and bio-leaching. Today, Hengtai shares the most typical Heap Leaching-Solvent Extraction-Electrowinning (SX-EW) full process flow, showing you how low-grade mines can achieve maximum economic returns with the right equipment setup.

1. Ore Preparation (Crushing, Screening & Agglomeration)

Before heap leaching, the mined copper ore must undergo strict physical preparation to ensure optimal permeability and maximum chemical contact area.

• •            Crushing: The run-of-mine (ROM) copper ore is crushed to the target particle size (typically P80 = 10–30 mm). This increases the exposure of copper minerals to the leaching agent. For high-capacity and reliable size reduction, you can explore Hengtai's premium Crushing Equipment solutions.

• •            Screening: This step separates fine particles from coarse aggregates, preventing fine dust from clogging the percolation channels within the heap. Ensuring accurate particle distribution requires high-efficiency sorting, such as Hengtai's durable Screening Equipment.

• •            Agglomeration (Optional): For fine-grained ores or clay-rich ores, a rolling agglomeration process with water, sulfuric acid, or binders is used to form porous pellets. To produce uniform, high-strength granules and handle fine fines, Hengtai's high-performance Sand Making & Agglomeration Machine is widely utilized in modern production lines.

2. Heap Construction and Pad Preparation

• Pad Line & Drainage: A reliable anti-seepage layer (typically HDPE geomembrane) is laid out to prevent environmental leakage, equipped with a comprehensive pregnant leach solution (PLS) collection pipe network.

• Stacking: The prepared ore is stacked into heaps, usually 4 to 8 meters high. Continuous conveyors or mobile trippers are used to minimize compaction and maintain uniform bulk density.

• Irrigation System: Drip emitters or wobbler sprinklers are installed across the top of the heap to ensure a highly uniform distribution of the lixiviant.

3. Leaching Reaction (Sulfuric Acid System)

• Lixiviant: A diluted sulfuric acid solution (pH 1.0–2.0, with a concentration of 10–30 g/L H₂SO₄) is continuously applied.

• Chemical Reactions (Oxidized Copper Ore):
             CuO + H₂SO₄ → CuSO₄ + H₂O            *(For chalcopyrite/sulfide copper ores, acidophilic bacteria like Acidithiobacillus ferrooxidans are introduced for bio-oxidation).*

• Process Dynamics: The typical irrigation rate ranges from 5 to 20 L/(h·m²) with a cycle of 30 to 180 days. The resulting copper-rich solution (PLS) flows into the collection ponds.

4. Solvent Extraction (SX)

Because the copper concentration in the heap leach PLS is generally low (1–6 g/L), it must be enriched through solvent extraction before entering the electrowinning stage.

• Extraction: The PLS is mixed with an organic extractant (e.g., LIX 984N). Copper ions are selectively transferred into the organic phase:
             Cu²⁺(aq) + 2RH(org) → CuR₂(org) + 2H⁺(aq)

• Stripping: The loaded organic phase is then contacted with a highly acidic spent electrolyte (150–180 g/L H₂SO₄). Copper re-enters the aqueous phase, generating an advanced electrolyte with 35–50 g/L Cu²⁺.

5. Electrowinning (EW)

• Cell Setup: High-purity copper is deposited using insoluble anodes (lead alloy or DSA) and stainless steel permanent cathode blanks.

• Parameters: Electrowinning operates at 35–45°C with a current density of 200–350 A/m².

• Cathode Reaction: Cu²⁺ + 2e⁻ → Cu(s) (Yielding 99.99%+ pure copper cathodes after a 5–10 day cycle).

6. Tailings Remediation & Environmental Control

• Rinsing & Neutralization: Post-leaching, the spent heap is rinsed with water or alkaline solutions to neutralize residual acidity. Lime or limestone is added to the raffinate treatment ponds to precipitate heavy metals before safe discharge or recycling.

• Reclamation: The site undergoes reshaping, topsoil layering, and revegetation to ensure environmental compliance.

Custom Leaching and Processing Lines by Ore Type

Get Your Customized Processing Layout from Hengtai

Every mining asset possesses unique mineralogy and site conditions. Shandong Hengtai Intelligent Manufacturing Equipment Technology Co., Ltd. specializes in complete stationary and mobile crushing, screening, and mineral processing plant engineering.

Contact Our Engineers Today