With the rapid development of the PCB manufacturing industry, alkaline etching solution has become one of the largest sources of wastewater generated during the production process. This wastewater contains a high concentration of copper ions. Direct discharge not only causes environmental pollution but also results in the loss of valuable metal resources. Therefore, achieving efficient copper recovery and recycling of alkaline etching solution has become an important approach for PCB manufacturers to reduce production costs and promote green manufacturing.

At present, the Solvent Extraction–Stripping–Electrowinning (SX-EW) process has become a mature and widely adopted technology for copper recovery from alkaline etching solution. This process efficiently separates copper ions from the wastewater and recovers them as high-purity electrolytic copper, while simultaneously regenerating the etching solution for reuse, improving resource utilization and reducing wastewater treatment costs.

Copper Recovery Process from Alkaline Etching Solution

The copper recovery system from alkaline etching solution mainly consists of three process stages: solvent extraction, stripping, and electrowinning.

During the extraction stage, the alkaline etching solution comes into full contact with a specialized copper extractant, allowing copper ions to be selectively transferred into the organic phase and separated from the etching solution. The copper-loaded organic phase then enters the stripping stage, where it is contacted with sulfuric acid to produce a copper sulfate solution. The copper sulfate solution is subsequently fed into the electrowinning system, where electrolytic copper with a purity of over 99.95% is produced. Sulfuric acid generated at the anode can be recycled back to the stripping stage for reuse.

Application of the CWL-M Centrifugal Extractor Copper Recovery from Alkaline Etching Solution

Extraction equipment plays a critical role in determining copper recovery efficiency and the stable operation of the entire process. Developed by Zhengzhou Tiei Extraction Technology Co., Ltd., the CWL-M Series Centrifugal Extractor integrates liquid-liquid mixing and mass transfer with phase separation into a single unit by utilizing a high-speed centrifugal force field, enabling continuous solvent extraction.

Compared with conventional mixer settlers, the CWL-M Series Centrifugal Extractor offers higher mixing efficiency, faster phase separation, lower extractant loss, a smaller footprint, and a higher degree of automation. These advantages help improve copper recovery efficiency, reduce operating costs, and support continuous production.

During operation, the alkaline etching solution and the extractant are fed separately into the centrifugal extractor. After multistage counter-current extraction, the copper-loaded organic phase enters the stripping stage, where copper ions are transferred and concentrated, forming a stable and efficient closed-loop process.

Zhengzhou Tiei Extraction Technology Co., Ltd. specializes in the research, development, and manufacturing of liquid-liquid extraction equipment. The CWL-M Series Centrifugal Extractor is widely used in applications such as copper recovery from alkaline etching solution, hydrometallurgy, and valuable metal recovery.

The equipment can be selected and configured according to the customer's processing capacity and operating conditions. Featuring stable operation, a compact footprint, a high level of automation, and easy maintenance, it meets the requirements of continuous production and provides efficient and reliable liquid-liquid extraction equipment for copper recovery systems from alkaline etching solution.
Email: sales@tieiextraction.com
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