Acid recovery and metal removal

Maximise your process efficiency

Acid recovery is an innovative membrane technology that converts contaminated pickling acid into a reusable pickling solution and a metal-rich concentrate. By recovering valuable free acid and selectively removing metal salts, you lower your operating costs and maintain the quality of your pickling bath.

What is it?

What is acid recovery and metal removal?

Acid recovery is mainly used in steel pickling and also in aluminium anodising, for example in galvanising plants and wire drawing mills.

During the pickling process, an acid reacts with a metal, forming metal salts.

This technology continuously removes those metal salts from the bath, so the acid can be recovered.

Stability: Keeps both the acid and iron concentration in your pickling bath constant.
Recovery: Achieves acid recovery rates of 80% to 95%.
Efficiency: Eliminates the need to periodically dispose of and replace large portions of your pickling bath.

When should you choose acid recovery?

Acid recovery is the ideal solution when you aim for a more stable production process, lower operating costs and a smaller environmental footprint.

Operational benefits

Consistent process quality

By keeping the metal concentration low, the pickling rate remains constant. This ensures reproducible quality of your treated products and prevents process delays.

Less maintenance and downtime

Since the pickling bath no longer needs to be fully replaced at regular intervals, you reduce line downtime and the risks involved in handling large volumes of fresh and contaminated acid.

Economic & sustainable benefits

Savings on chemicals You need to purchase significantly less fresh acid, because the free acid present is continuously recovered. Only the consumed acid and a minimal loss fraction need to be topped up.

Lower disposal costs The volume of contaminated acid to be disposed of drops drastically. The metal-rich waste stream can often be treated more efficiently in your own wastewater treatment plant or disposed of at a lower cost.

How does the system work?

The principle is based on a selective, positively charged membrane. The system uses two incoming streams that are pumped along the membrane in counterflow: the contaminated acid (feed) and demineralised water (DI water).

The separation

The positively charged membrane repels the positive metal ions, while negative chloride ions and small hydrogen ions (free HCl) can migrate through it.

Recovery

The free acid returns to your pickling bath.

Waste

The metal salts remain in a stream that goes to wastewater treatment or disposal.

In which sectors is acid recovery essential?

Our acid recovery and iron removal solutions are widely used in industries that rely on high-quality surface treatment and metalworking.

Galvanising plants

When pickling steel prior to hot-dip galvanising, acid recovery helps keep the iron concentration in the hydrochloric acid (HCl) bath stable.

Wire drawing mills

In continuous pickling processes, the technology ensures a consistent pickling bath quality, which is crucial for further mechanical processing of the wire.

Steel industry & tube manufacturing

By continuously removing iron salts such as FeCl₂ en FeCl₃, the pickling rate remains optimal and the loss of valuable acid is kept to a minimum.

Anodising & surface treatment

The technology is the ideal choice for any process bath where metal contamination reduces efficiency and periodic discharge of contaminated acid used to be the only option.

Certainty through measurement: pilot tests and lab analysis

No two pickling processes are the same. That's why at PCA Water, we don't guess at results. Before designing an installation, we make performance tangible by thoroughly testing your specific process fluid.

Our in-house lab

Through precise titrations and chemical analyses, we map the exact ratio between free acid and metal salts. This data forms the foundation for correct, customer-specific sizing.

On-site pilot installation

Want to experience the efficiency in your own production environment? PCA has a mobile pilot installation.

Validation: we determine the optimal parameters for the highest recovery rate of your bath.
Rapid analysis: immediate lab results allow settings to be optimised on the spot.

Interested?

FAQ: frequently asked questions about acid recovery & iron removal

Does PCA offer a complete solution?

Absolutely. PCA offers a tailor-made turnkey solution, with the membrane unit at its core and, depending on the application, additional components such as a heat exchanger, an RO installation for DI water and the necessary dosing equipment.

What if the temperature of my pickling bath is high?

The membranes can withstand temperatures of up to 35–40 °C. If your bath is warmer, we provide a heat exchanger to cool the acid safely before treatment.

Can the consumed acid be topped up automatically?

Yes, we recommend integrating a continuous dosing system. This system, which we can supply, guarantees a constant acid concentration throughout the entire production cycle.

Experience the difference with PCA Water.

Want to know how much acid you can save in your process? Contact us.

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