In the hot-dip galvanizing and metal processing industries, the treatment and resource recovery of zinc-containing pickling waste liquor is an important issue that requires balancing environmental protection with economic benefits. Conventional methods such as neutralization–precipitation and evaporation–concentration generally suffer from limitations including low separation efficiency, high energy consumption, and a tendency to generate secondary pollution. In particular, the coexistence of high concentrations of iron ions in the waste liquor severely restricts the effective recovery of zinc resources.
To address this industry bottleneck and the selection of suitable equipment for zinc recovery from pickling waste liquor, Zhengzhou Tiei Extraction Technology, based on the CWL-M series centrifugal extractor, has innovatively developed an efficient and environmentally friendly integrated zinc–iron separation process featuring “pretreatment–extraction–scrubbing–stripping.”

In this process, the pickling waste liquor is first subjected to pretreatment, in which iron powder reduction and filtration are employed to obtain a stable zinc-extraction feed solution. Subsequently, in the CWL-M centrifugal extractor, the feed solution is brought into highly efficient contact with a dedicated extractant, enabling rapid mass transfer and the selective enrichment of zinc ions. The loaded organic phase is then scrubbed with an acidic medium to remove impurities, followed by desorption using an alkaline stripping agent to finally obtain a high-purity zinc-rich strip liquor.
Through subsequent operations such as precipitation and calcination, a high-purity anhydrous zinc chloride product with stable quality can be produced. The zinc recovery rate can exceed 99.9%, and the regenerated organic phase can be recycled, significantly reducing overall operating costs.

The Tiei Extraction CWL-M centrifugal extractor, as the core equipment of the process, utilizes a high-speed centrifugal force field to enhance the mixing and phase separation processes. It effectively solves the problems of incomplete zinc-iron separation and severe entrainment encountered in traditional methods, and also offers the following outstanding advantages:

  • 1.High efficiency and stability: A multistage countercurrent configuration enables continuous operation with high extraction efficiency and stable performance.
  • 2.Strong adaptability: The equipment features excellent corrosion resistance and impact resistance, allowing it to accommodate complex acidic systems and fluctuations in flow rate.
  • 3.Environmentally friendly and energy-saving: A fully enclosed design minimizes solvent volatilization, ensures low solvent loss in the system, and reduces overall energy consumption by more than 30% compared with traditional processes.
  • 4.Compact footprint: The modular design significantly saves plant floor space and facilitates retrofit, expansion, and upgrading of existing production lines.

Centrifugal extraction technology has been successfully applied in multiple metal processing enterprises. It not only enables high-value recovery of zinc resources from waste liquor, but also significantly reduces hazardous waste disposal costs and associated environmental risks.
Email: sales@tieiextraction.com
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