Products and solutions, 2011-04-01, 04:18 PM
Two major projects secure ThyssenKrupp VDM entry into zirconium market
The production of high-performance materials for heat exchangers has long been part of the core business of ThyssenKrupp VDM. Now the production of zirconium sheet and plate is opening up a highly attractive market for the Werdohl-based company. Two lucrative contracts from the chemical industry are contributing to this: a heat exchanger for an acrylic acid plant and a reactor for an acetic acid plant. Organic acrylic and acetic acid are highly corrosive and extremely aggressive but at the same time important feedstocks for the chemical industry. Demand for acrylic acid has increased rapidly in recent decades. The steep rise in demand is mainly due to the use of superabsorbent polymers in the hygiene industry. These are employed among other things to control moisture in food packaging and cable sheathing. Acetic acid is mainly used in the food industry and in the production of paints and dyes.
The production of these two acids requires extremely corrosion-resistant materials. Apart from zirconium, which ThyssenKrupp VDM recently added to its product range, no other material is able to meet this challenge in certain parts of chemical plants. Zirconium is used in chemical technology as a material for process equipment, heat exchangers, pumps, fittings and piping, especially when sulfuric and hydrochloric acids are involved.
The mineral zircon has been known as a gemstone since ancient times. Today the industrial use of zirconium plays a much more important role. It is a strong, ductile, shiny silver metal with a much lower density than steel and nickel alloys, and offers great resistance in highly corrosive environments. Zirconium owes its outstanding corrosion resistance to a passivating oxide coating which forms very quickly on its surface upon contact with aqueous media. The use of this material is therefore recommended both technically and economically in terms of its price to lifetime ratio. It protects equipment and piping in chemical plants reliably against most organic and inorganic acids as well as against strong alkali and saline solutions. Zirconium has high chemical stability, can be readily machined, is easy to weld and is fully recyclable. These properties make the material suitable for a variety of uses.
In the middle of last year ThyssenKrupp VDM installed a completely new spray pickling line at its Altena plant to enable it to produce zirconium sheet and plate. The Werdohl-based company produces zirconium in different alloys, the conventional one being Zr702. Zr 700 is a low oxygen alloy which because of its higher ductility is even used for explosive cladding. This is a process in which two different metals are bonded together by the use of explosives. Usually, a less costly, thicker base material, e.g. steel, is clad with a more valuable corrosion-resistant material, in this case zirconium. Explosive cladding creates a metallic bond between the two materials.
ThyssenKrupp VDM’s particular expertise lies firstly in its excellent materials know-how and secondly in its longstanding knowledge of the processing of high-performance materials. This has now enabled the company to add to its material portfolio and gain access to the important zirconium market, with a global demand of roughly 6,000 metric tons per year.