Industrial pickling facility

Service center – cutting facility

Promostal has expanded its offering with a state-of-the-art industrial pickling facility, providing comprehensive surface treatment for stainless steel. Our innovative technological solution enables effective chemical processing that meets the highest quality and environmental standards.

Our pickling facility allows for the treatment of large-scale components, such as tanks, steel structures, and other advanced elements.

Chamber dimensions:

length: 18 m,
width: 8,5 m,
height: 6 m.

Maksimum dimensions of pocessed components:

length: 13 m,
width: 4,8 m,
height: 4,5 m.

Advanced Chemical Processing Technology

I. Pre-cleaning

Pre-cleaning (degreasing) involves the removal of contaminants from metal surfaces, including soluble salts, grease residues, and remnants of mechanical processing. Contaminants can cause inconsistencies in pickling and passivation, so pre-cleaning is performed every time.

II. Pickling

The pickling process aims to achieve a metallurgically clean surface by removing the surface layer of iron from the base metal, as well as discoloration, oxidation, and other metals. This process is carried out using localized spraying with nitric acid HNO₃ (V), hydrofluoric acid HF, and phosphoric acid H₃PO₄.

III. Passivation

To accelerate and stabilize the protective coating, after pickling, the processed item undergoes passivation. Passivation results in the formation of a thin oxide layer on the metal surface, which provides high resistance to chemical agents and environmental conditions. This process is crucial for corrosion protection of acid-resistant steel. It is performed locally using a spray application of an aqueous nitric acid (V) solution with a concentration of 30-55%, or a mixture of chromic acid (H₂CrO₄) and sulfuric acid (H₂SO₄). After completion, steel components are rinsed with a water jet.

IV. Rinsing

Rinsing is performed after each pickling and passivation process, regardless of whether the processes were conducted using immersion or spraying. High-pressure water is used for this step, which takes place in a designated area within the processing facility.

V. Neutralization and Precipitation of Residues

Wastewater from chemical metal processing is acidic and contains heavy metals (primarily steel and nickel as byproducts of steel dissolution). Initially, wastewater is neutralized by an alkaline agent. Then, in a filter press, through decantation, heavy metal residues are separated from neutralized wastewater. The separated residues are disposed of properly. Continuous pH monitoring at the discharge point ensures the quality and safety of wastewater disposal, with real-time measurements recorded in a log.

Each stage of the process complies with the highest standards of quality and safety.

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