Pickling is an essential process in the metal processing, electroplating, and steel industries. However, the resulting pickling wastewater, rich in hydrochloric acid and heavy metals, has long been a major environmental challenge and financial burden for companies. Traditional lime neutralization methods not only waste valuable ferrous chloride resources but also generate large amounts of iron-containing sludge that is difficult to treat. Today, a new efficient solution is emerging as a favorite in the industry: the solvent extraction method combined with centrifugal extractor enables the efficient extraction of high-purity ferric chloride (FeCl₃) from pickling wastewater.
Outstanding Features of the Tiei Extraction CWL-M Centrifugal Extractor
Although the solvent extraction method is highly effective, its industrial application has long been constrained by the limitations of traditional extraction equipment such as mixer settlers and column equipment—which often suffer from low efficiency, large footprint, emulsion formation, and difficulty in achieving continuous operation. The emergence of the centrifugal extractor perfectly addresses these challenges, making it the ideal partner for this technology.
1.High mass transfer efficiency: The high centrifugal force generates an extremely large interfacial area, resulting in outstanding extraction and stripping efficiency, with a single-stage extraction efficiency exceeding 95%.
2.Rapid phase separation: The powerful centrifugal force enables liquid-liquid two phases with similar density to be completely separated within seconds, effectively solving the problems of slow separation and easy emulsification in traditional mixer-settlers.
3.Short residence time: The feed solution remain inside the machine for only a few seconds, reducing FeCl₃ corrosion on the equipment and avoiding the degradation of certain substances.
4.Continuous and automated operation: The CWL-M centrifugal extractor is designed for continuous production and can be easily integrated with DCS or PLC systems, enabling full-process automatic control suitable for modern large-scale production.
5.Compact footprint: A single centrifugal extractor can replace an entire set of mixer settlers, significantly saving plant space.
6.Sealed operation: The fully enclosed system prevents solvent evaporation, improves the working environment, protects operator health, and reduces solvent losses.
Process Flow for Extracting Ferric Chloride from Pickling Wastewater
1.Pretreatment: The pickling wastewater is first filtered to remove solid suspended particles.
2.Extraction: The pretreated wastewater is brought into countercurrent contact with a specific extractant in the CWL-M centrifugal extractor. The extractant selectively “captures” the iron ions from the wastewater, achieving effective separation of iron from impurities.
3.Stripping: The extractant loaded with iron ions (the loaded organic phase) enters the stripping section, where it contacts dilute hydrochloric acid. The iron ions are stripped into the aqueous phase, forming a high-purity ferric chloride solution.
4.Regeneration: The stripped extractant is reactivated and recycled back to the extraction section for reuse, with minimal loss.
5.Post-treatment: The resulting high-purity ferric chloride solution can be sold directly as a liquid product or further concentrated and crystallized into solid ferric chloride. The raffinate (extracted wastewater) is then sent to a subsequent treatment system for discharge in compliance with environmental standards.
Recovering ferric chloride from pickling wastewater using the CWL-M centrifugal extractor is a technologically advanced and economically viable resource recovery technology. It transforms hazardous waste into valuable products while simultaneously reducing wastewater treatment costs and environmental pollution at the source, perfectly aligning with the concepts of clean production and a circular economy.
For more details, please contact Tiei Extraction.
Email: sales@tieiextraction.com
Whatsapp: +86 19069612820
