Large quantities of heavy metal-containing sludge are generated every year by the electroplating, printed circuit board (PCB) manufacturing, and metal surface treatment industries. Among them, copper (Cu) and nickel (Ni) are two of the most valuable metals for recovery. Recovering copper and nickel from electroplating sludge in a green and efficient manner is no longer merely an environmental compliance requirement; it has become an important way for enterprises to reduce costs, improve efficiency, and extend their industrial value chains.

Liquid-liquid extraction (solvent extraction) technology, with its advantages of excellent selectivity, high separation efficiency, and continuous operation capability, has become the preferred process for extracting high-purity copper and nickel from complex sludge leach solutions. The core equipment of this process—the CWL-M Centrifugal Extractor—directly determines recovery rates, product quality, and operating costs.

Technical Challenges: Limitations of Traditional Extraction Equipment

In acid leaching or ammonia leaching systems for electroplating sludge, copper and nickel often coexist with impurity ions such as iron, zinc, and chromium. Traditional mixer-settlers or extraction columns commonly suffer from the following drawbacks:

Severe entrainment: Incomplete phase separation leads to high organic phase losses and increases the burden on subsequent scrubbing and stripping processes.
Low mass transfer efficiency: Stage efficiency is affected by flow fluctuations, making it difficult to maintain stable extraction performance.
Large footprint: Multi-stage operations require extensive plant space and high civil construction investment.
Poor adaptability: Sensitive to solids content in the feed solution, prone to clogging, and requires frequent maintenance.

These shortcomings make it difficult for many enterprises to achieve long-term stable operation even after building extraction production lines, let alone realize satisfactory economic benefits.

CWL-M Series Centrifugal Extractor: A Solution for Efficient Copper and Nickel Recovery

The CWL-M Series Centrifugal Extractor independently developed by Zhengzhou Tiei Extraction Technology Co., Ltd. is a highly efficient liquid-liquid extraction and separation equipment specifically designed for hydrometallurgy and hazardous waste resource recovery. This series has demonstrated outstanding performance in the industrial recovery of copper and nickel from electroplating sludge, effectively addressing the limitations of traditional equipment.

Key Advantages

1.Ultra-High Separation Factor Ensures High-Purity Copper and Nickel Products
The CWL-M centrifugal extractor adopts a high-speed rotating drum structure that generates a centrifugal force field hundreds of times greater than gravity, enabling rapid mixing and precise phase separation of the organic and aqueous phases within a very short time. Compared with gravity-settling equipment, its separation performance is improved several times over, significantly reducing organic phase entrainment. This greatly lowers impurity carryover in the loaded organic phase and ensures that the stripped copper or nickel salt solutions meet high-purity standards suitable for electrowinning or crystallization processes.

2.Stable Stage Efficiency and Adaptability to Large Flow Variations
The internal structure has been optimized through CFD analysis. Mixing intensity and residence time can be adjusted to maintain a stable stage efficiency of ≥95% under varying flow rates and phase ratios. Regardless of fluctuations in copper and nickel concentrations within the sludge leachate, stable recovery performance can be achieved.

3.Closed Operation for Safety and Environmental Protection
The fully enclosed design prevents the volatilization and leakage of organic solvents (such as sulfonated kerosene and extraction reagents), improving the operating environment while reducing solvent losses. This design complies with internationally recognized EHS (Environment, Health, and Safety) management requirements.

4.Corrosion Resistance, Particle Tolerance, and Long-Term Continuous Operation
Key components are manufactured from high-quality stainless steel or special alloys. To accommodate trace suspended solids in electroplating sludge leach solutions, the feed distributor and rotor clearance have been specially optimized. The equipment offers excellent anti-clogging and wear-resistant performance, significantly extending cleaning intervals and enabling annual operating times of more than 8,000 hours.

5.Modular Design and Flexible Configuration
The CWL-M centrifugal extractor supports single-stage or multi-stage configurations (including counter-current washing and complete extraction–scrubbing–stripping processes). Process layouts can be flexibly designed according to the actual copper, nickel, and impurity contents of the feed solution. The equipment is compact and lightweight, significantly reducing plant space requirements while facilitating upgrades and capacity expansions of existing production lines.

Application Process: CWL-M Centrifugal Extractor in Copper and Nickel Extraction

Using the sulfuric acid leaching–solvent extraction–electrowinning/crystallization route for electroplating sludge as an example:

Leaching: The sludge undergoes acid leaching or bioleaching to produce a solution containing Cu²⁺, Ni²⁺, and impurities.

Copper Extraction: Using copper extractants (such as the LIX series), the feed solution is mixed with the extractant in the CWL-M centrifugal extractor extraction stage. Copper ions are selectively transferred into the organic phase, while the raffinate proceeds to the nickel recovery stage.

Scrubbing: The loaded organic phase containing copper enters the scrubbing stage, where dilute acid is used to remove entrained impurities.

Copper Stripping: After scrubbing, the organic phase is mixed with a high-acidity stripping solution in the CWL-M centrifugal extractor stripping stage. Copper ions are transferred back into the aqueous phase, producing a high-concentration, high-purity copper sulfate solution for electrowinning to produce cathode copper.

Nickel Extraction: The raffinate from the copper extraction stage is adjusted to the appropriate pH and treated with nickel extractants (such as P204 or Cyanex series extractants) in another CWL-M centrifugal extractor extraction cascade. A similar extraction, scrubbing, and stripping process is carried out to produce nickel sulfate solution for nickel salt production or nickel electrowinning.

In every extraction, scrubbing, and stripping stage described above, the CWL-M centrifugal extractor provides rapid and clear phase separation along with high mass transfer efficiency, ensuring high overall recovery rates (copper recovery exceeding 98% and nickel recovery exceeding 96%) while minimizing reagent consumption.

Zhengzhou Tiei Extraction Technology Co., Ltd. is a high-tech enterprise integrating R&D, design, manufacturing, and sales, specializing in liquid-liquid extraction and separation technology and equipment. The company offers the complete CWL-M Series centrifugal extractor product line, ranging from laboratory-scale units to large industrial systems. These systems have been successfully applied in numerous domestic and international projects involving non-ferrous metal smelting, spent lithium battery recycling, and electroplating sludge treatment, accumulating extensive process expertise and commissioning data.

If you are facing pressure from electroplating sludge disposal or looking to improve the efficiency and profitability of your existing copper and nickel recovery operations, welcome to contact us for CWL-M centrifugal extractor technical information, equipment selection recommendations, or sample testing support.
Email: sales@tieiextraction.com
Whatsapp: +86 19069612820