VDM Metals adopts Henkel's nitric acid-free pickling process

A German manufacturer of nickel alloys and specialty stainless steel, VDM Metals Group, has adopted Henkel's next-generation, nitric acid (HNO3)-free Bonderite C-CP ("Cleanox") pickling process for specialty wire products. The Bonderite C-CP product range meets market requirements in the metals industry to significantly enhance the sustainability value of production processes. Cleanox technology has been used for decades across many sectors worldwide, including wires, tubes, coils, rods and components. It is suitable for all stainless steel grades and can be used in numerous applications including immersion, spray, continuous line or batch solution processes. VDM Metals, based in Werdohl, uses Henkel's Cleanox technology to clean rolled wires of high-alloy materials to comply with NOx limits. Bjoern Lorenz, West Europe Metal Coil Sales Manager at Henkel, stated, "Henkel is committed to playing a decisive role in environmental protection, in line with our company strategy, by offering our customers reliable, flexible and sustainable pickling processes for stainless steel in the metal coil industry. Customers like VDM Metals benefit from competitive production costs while making a significant contribution to both ecological improvement and production safety. Together with our chemical and electric pickling systems paired with equipment to automatically control and dose chemicals, we can offer our customers focused on increasing sustainability a systematic package." High-alloy nickel-chromium alloys are widely used in many industries including automotive, petrochemical, aerospace, power generation and electrical, chemical and domestic appliances sectors. However, challenges exist in commonly used mixed acid pickling systems due to nitric acid use. These cleaning techniques typically result in the discharge of large volumes of nitrate ions during intermediate and final rinsing stages. Nitrate and nitrite contamination is subject to legal regulations and must comply with wastewater treatment directives. Another disadvantage of common mixed acid pickling processes is the necessity to treat nitrogen oxide (NOx) fumes to prevent air pollution. While it is technically possible to clean nitrogen oxides through different procedures, it requires equipment, process control and maintenance investments.

Both factors determine the productivity of the pickling process, wastewater treatment and waste disposal.

Henkel's Bonderite C-CP, with the latest innovations in its nitric acid-free cleaning technology series, overcomes these environmental and cost barriers. Another sustainability advantage is that the amount of sludge generated by the new technology is lower compared to the conventional process. Moreover, when this fully automatic technology is used, global process costs are equal to or lower than conventional processes. The Bonderite C-CP process can be used in spray or immersion lines. It is suitable for austenitic, ferritic, martensitic, duplex or superduplex-based stainless steel of any grade or specialty qualities, including high-chromium AISI/SAE 4XX grades. Olaf Kazmierski, Senior Vice President responsible for production at VDM Metals in Werdohl, is very positive about both the sustainability potential of the new technology and the cooperation with Henkel. "Adopting Bonderite C-CP enabled us to optimize our pickling process. Henkel's advice on how to manage the process and how to optimize consumption formed the basis for a seamless transition from mixed acids to Bonderite technology. The problem of nitrate loads has been clearly reduced. Meanwhile, the process is running smoothly, the new pickling procedure is well established."

The latest innovation in the Cleanox series is the use of acid recovery pickling machines that make the technology more cost-effective and sustainable.

This equipment is provided by Henkel to fulfill multiple purposes, but primarily to further reduce sludge remaining in the production system and to recycle spent Bonderite C-CP products. By using these machines, customers can achieve significant savings in product consumption costs and further reduce their ecological footprint. Henkel began offering its range of Bonderite C-CP technologies in the 1990s to meet growing market demand for nitric acid-free pickling technologies for stainless steel. Since that beginning, legislation governing this field in the EU has been tightened in accordance with the European Community Directive (96/82/EC) (known as "Seveso"), which further restricts the use and storage of hydrofluoric acid. Henkel's latest generation Bonderite C-CP is fully compliant with these legal requirements. VDM Metals is among the first high-alloy non-ferrous metal producers to adopt the process in their production. Aziz Mabrouki, Head of Metal Coil Europe at Henkel, frames the issue: "Cleanox technology has become widespread not only in Europe, but throughout the world. We can provide integrated solutions ranging from chemistry to expertise and equipment to support stainless steel producers and users in complying with new directives, such as regulations from China's central government regarding nitrite emissions." IMAGE CAPTION VDM Metals adopts Henkel's nitric acid-free pickling process. (Photo: VDM Metals, PR087)