Production is based on pioneering standards and in accordance with our aims of best possible environmental compatibility and sustainability. Already during the planning phase, all the structures required for production were also assessed and shaped according to ecological aspects.

Further information is available under: Dülmen

At the time of delivery and installation into the respective furnace, all carbon-bonded products are in an “unfinished” state. The actual properties in the magnesia carbon bricks do not become active until they are used in steel works and come into contact with liquid steel. Due to the high temperatures during the application, the bricks go through a process in which many application-related properties change.

All mechanical and physical properties in the magnesia carbon bricks depend on the thermal history, meaning their working temperature. In the furnaces, temperature profiles develop from the hot face to the cold side of the lining. Accordingly, the properties of the magnesia carbon wear lining change constantly, from pre-heating until the last charging in the furnace, which causes inhomogeneous properties inside the bricks to be distributed. Different emissions can be released particularly during the pre-heating phase of a furnace lined with magnesia carbon bricks. In contrast to the pitch-bonded products, REFRAFLEX^® bonded bricks produce non-poisonous emissions, though they are frequently perceived as unpleasant due to the smoke and odors they emit.
After the successful introduction of the REFRAFLEX^® bonding system, Refratechnik developed thermally treated MgO-C-bricks:
The CERAMAC^® product line.

Pre-firing, which occurs in the range of the working temperatures, causes a partial ceramic bond to form that endows the bricks with completely new
properties. This ceramic bond is based on the reduction and oxidation of MgO or Mg:
Reduction: MgO + C ➞ Mg (g) + CO
Reoxidation: 2 Mg (g) + O2 ➞ 2 MgO

The CERAMAC^® brick stands out due to its unique combination of a flexible carbon bond with a stable ceramic bond. In the process, the bond matrix is graphitized, which has a positive impact on the mechanical properties and the oxidation behavior of the products. Thermal pre-treatment removes all of the volatile components from the bricks so that when they are pre-heated or used, no smoke or odors are released.

The CERAMAC^® product line has undergone comprehensive testing and been tried in different standard applications, thus proving its benefits, which include service life increases of up to 10%.

Emission-free pre-heating as well as the increased service life make the CERAMAC^® brick one of the most intelligent refractory solutions in steel production.

In order to solve this problem, Refratechnik has come up with its own innovative solution in the form of an anti-wetting system. This unique feature of REFRALUMAX 87 forms a protective layer on the hot face of the brick lining, protecting the wear lining against infiltration and corrosion. This new and patented system can withstand temperatures of up to 1200 °C.

REFRALUMAX 87 is a new kind of refractory brick which has been specially developed for use in secondary aluminium production. The brick has already proven its worth in various leading institutes over the world. Research organisations such as SINTEF and CIR have attested to its high level of corrosion resistance when in contact with liquid aluminium and aluminous alloys.

The high-quality aluminium refractory brick REFRALUMAX 87 is the first choice for the lining of aluminium smelting furnaces.

* > 85% Al; Si < 0.15%; Fe < 0.20%; Cu 1.7-2.1%; Mg 2.7-3.0%; Zn 6.8-7.2%;



REFRALUMAX 25 – The refractory brick for the reduction cell

The refractory lining of the base of electrolysis cells for primary aluminium production is subjected to major stress. Contact with the different salts and fluorides in particular requires a high-quality refractory product which is able to guarantee as high a durability as possible for the lining. Over the past few years, fireclay or aluminium silicate bricks have prevailed here.

The REFRALUMAX 25 is a refractory brick made from specially selected raw materials. Thanks to its low aluminium oxide content and optimised pore structure, the barrier brick boasts an excellent resistance to cryolite. The effects of infiltration and corrosion are minimised and superb heat resistance is guaranteed thanks to a vitreous, hot face barrier layer.

As a result, REFRAFLEX^® offers all the advantages of pitch bonding while eliminating its main disadvantages: Because of the characteristic polycyclic aromats pitch is no longer tolerable in the steel industry.

For Refratechnik Steel it was important to meet the technical challenge and develop a process that combines the advantages of both bonding systems while eliminating their disadvantages. With REFRAFLEX^® we have been successful.


The before and after effect:
Classic resin bonding versus REFRAFLEX^® bonding
The following pictures show the macroscopic and structural differences between resin bonding and a REFRAFLEX^® bond based on the same resin using macro pictures and scanning electron microscope pictures. For this, suitable samples were coked for six hours each at differing temperatures in the coking bed.

Even at the macroscopic level, the difference between the glass carbon shining like paint and the scaly, metallic shine of the graphite from the REFRALEX^® bond can be recognized.

Through the heat treatment at 1500 °C spherical areas can be seen with the normal resin bonding next to amorphous phases, which indicate the beginning of the crystalization or vaporization processes. With the REFRAFLEX^® bond on the other hand, these amorphous structures are no longer present. The lamellar layered structure of a well graphitized carbon is much more recognizable, which makes the refractory brick so flexible that it does not crack from stresses.