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During our visit, plant manager Holger Friedrich drinks his coffee from a mug featuring the periodic table of elements. This is a small detail that says a lot. Because when the manager of the reduction plant talks about the LAUX process, it certainly doesn’t sound like business as usual. “It’s almost like alchemy,” he says. Solid iron is machined; liquids flow; gases are produced; heat is released. Substances change their form—and a muddy, dark mass transforms into vibrant pigments of red, black, or yellow. “Such a wide variety of processes—especially the combination of inorganic and organic chemistry—is rarely found today, particularly within a single facility,” he explains.

That is precisely what makes the LAUX process unique—it directly intertwines organic and inorganic chemistry. In a joint reaction, metallic iron is converted into iron oxide—in conjunction with the reaction of an organic starting material.

The fact that the facility is still referred to as a reduction plant has historical reasons. “Actually, we produce iron oxide pigments—in other words, we oxidize iron,” explains Friedrich. “The name comes from the fact that, through this oxidation, we simultaneously reduce nitrobenzene to aniline.” Because in the beginning, the focus wasn’t on the pigment at all. When the process was developed in the early 20th century, aniline—which was needed to produce synthetic dyes—was considered a valuable substance. The iron oxide accumulated as sludge, and for a long time no one knew what to do with it. It wasn’t until the mid-1920s that chemist Julius Laux recognized the potential of this byproduct—thereby laying the foundation for industrial iron oxide production.

Reduction Plant – Where Iron Is Turned into Pigment
The most important raw material for a reduction plant comes from the automotive industry—which, at first glance, has little to do with pigments. Iron shavings and metal scrap generated during the machining of castings are used. “So we were already committed to the circular economy even before the term officially existed,” says Christian Schütte, who has worked at the company for more than three decades and is in charge of raw materials procurement. "Sustainability has always been an integral part of our process."

However, not all waste is the same: “The quality of the iron we receive clearly plays a key role in determining the quality of the pigment,” explains the expert. In a huge warehouse, varieties with different grain sizes and qualities are therefore mixed together to produce the best possible raw material. The material is then mechanically processed in the grinding mills, graded, and prepared for the production process. In the reduction plant, the actual reaction then proceeds almost entirely automatically. This reaction is highly exothermic—meaning it releases large amounts of heat. This energy is put to good use: to generate steam and hot water for the plant’s own processes, as well as for other plants on the site. “In a sense, we’re IPG’s boiler room,” says Schütte.

From a Liquid Substance to a Solid Pigment
At the end of the process, the iron oxide leaves the reduction plant as an aniline-free paste—thick and completely free of any harmful substances. It is then transported via pipe bridges to the next facility: pastes and calcination. “This is where the product takes shape,” says plant manager Bartholomäus Luczak. “We turn the sludgy mass into a solid material.”

In terms of area, pastes and calcination is the largest facility in the Chempark: six large main buildings, five control rooms, and an extensive network of pipelines covering an area of about 5 hectares. Here, the thick paste is cleaned of iron residues, thickened, washed, and then dried. Then the next step depends on the color: Black or yellow pigments are produced directly from the process. To produce the red pigments, the black paste is then calcined—in other words, heat-treated.

This process takes place in the massive rotary kilns located in a separate section of the building, where temperatures reach up to 900 degrees Celsius. Regina Müller, assistant shift supervisor, is currently making her rounds there. It’s not just the scale that’s impressive—the entire atmosphere is striking as well. Over the years, the massive furnaces, pipes, and equipment have taken on the red color of the pigment calcined here. “It’s usually much warmer here,” she explains. “But our kilns are currently being serviced.”

Not Clean, but Colorful
Maintenance is generally an important issue for the Uerdingen team. The pigment is highly abrasive—screw conveyors, pipes, and equipment are subjected to enormous levels of stress during continuous operation. Equipment must therefore be inspected, serviced, and maintained on a regular basis. “Despite automation, you spend a lot of time moving around the plant, switching lines, and sometimes intervening manually,” says Müller. “That’s what makes the job so interesting to me.”

It goes without saying that the pigments don’t just color the hall and its surroundings—by the end of their shift, workers’ clothes bear visible traces of the product. “You don’t leave our plant clean,” says Müller, “but you do leave colorful.”

A Strong Whole — for 100 Years
After passing through the paste and calcination stages, the pigment’s journey still isn’t over. “We hand it off to our colleagues in the grinding department,” explains Müller. Here, the pigment undergoes further processing—it is mixed and either finely ground for its intended application or compacted into a low-dust form, depending on how and for what purpose it will later be used by the customer.

The closely integrated production network is one of the reasons why the process remains successful even after 100 years—and why it isn’t used anywhere else in the world. "Many process steps, long distances, large quantities. Material flows must be coordinated, and turnaround times must be met—around the clock. “It would be hard to imagine a single plant being able to handle this,” says Luczak. For Friedrich, too, close, collaborative partnership is crucial: “No matter which plant—we always say we make iron oxide together.” This team spirit, combined with 100 years of experience, isn’t something you can just copy.”

Mr. Ertl, LANXESS has been producing iron oxide pigments in Krefeld-Uerdingen using the LAUX process for 100 years. Why is it so successful?
The inventor of the process, Julius Laux, asked a surprisingly modern question some 100 years ago: What if waste wasn’t waste? It all began with the production of aniline from nitrobenzene and scrap iron—a process that generated large quantities of iron oxide as a byproduct. Laux realized that, under certain conditions, this iron oxide is particularly colorful and pure and is suitable as a high-quality pigment. To this day, the process is considered one of the most sustainable methods for producing iron oxide pigments. The combination of recycling metal waste and energy-efficient process steps has made the LAUX process a key factor in our success.

But you don’t just produce pigments in Germany, do you? How important is the global production network to IPG?
Extremely important. We have locations on all five continents. Here in Europe, we still process pigments in Spain and England, as well as in the United States, Brazil, China, and Australia. This geographic diversification is a key advantage, as it enables us to improve our delivery capabilities and makes us more resilient to trade conflicts, sanctions, export restrictions, political instability, or regional crises. At the same time, it is important that Germany remains a competitive location for businesses—especially when it comes to energy costs, which play a key role in our energy-intensive production. That’s why we’re further advancing energy optimization through targeted investments in our plants and processes.

100 years of tradition—where are innovations emerging right now?
We need a wide range of applications to keep our plants running at full capacity. That’s why we’re constantly tapping into new markets—even beyond traditional coloring applications. Battery technology is a perfect example. In addition to iron oxides, iron phosphates can also be used in the manufacture of lithium iron phosphate batteries. Following the successful production of iron phosphate at the pilot plant, IPG is now developing the large-scale process that will be implemented in the production facility. This market is growing rapidly worldwide, so we are actively advancing research in this area. Currently, LFP cathode materials and the corresponding batteries are primarily produced in China. So far, there hasn’t been enough capacity in Europe —and we want to change that.