Clinker from the
Steam kiln

Gray-fired clinker

through a second firing in the steam kiln.

As with all ring kiln clinkers, the first firing for our steamed clinkers takes place in our ring kiln. The second firing, the so-called “steaming,” is carried out in a finishing kiln.

The color of the clinkers after the first firing is crucial for the final gray shade. The darker the clinkers are when they come out of the ring kiln, the darker the result after the second firing in the steam kiln.

For example, a light, cream-white firing from the ring kiln will turn into a light gray after steaming.

more objects with steamed clinkers (DE only)

Refinement through
second firing

since 2020 with our own steam kiln in Erkelenz.

The fired ring kiln clinkers are heated again in the steam kiln to 900 to 1,000 °C and then reduced with gas.

Afterward, the goods are cooled with nitrogen.

The clay materials contained in the clinker change color in this atmosphere, depending on the undertone, to grayish, bluish, or black.

No firing is like the other

As in the ring kiln, the same applies to steaming: Each firing is subject to fluctuations. For example, it can happen that the color of the first firing shows through. This phenomenon often occurs on the backside.

The same characteristics apply to the steamed clinkers as to the ring kiln clinkers. The bricks are set by hand in the kiln and later packed by hand again. Cracks and chipped edges are always part of the appearance. Since the gray color runs through the entire clinker, it is also visible in possible cracks and chipped edges.

Coal firing marks from the firing in the ring kiln are still present after the steaming process.

Processing-
instructions

for steamed
clinkers

To achieve a uniform facade appearance, it is important to take the clinkers from several pallets on the construction site and mix them accordingly.

Furthermore, the use of acid, especially hydrochloric acid, should be expressly avoided during processing. This can lead to discolorations on the clinker, which are difficult to remedy.

Processing instructions for clinkers

Processing instructions for clinker slips

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