Refratechnik Cement GmbH

Göttingen, Germany

Refratechnik Cement GmbH

Göttingen, Germany
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Klischat H.-J.,Refratechnik Cement GmbH | Wirsing H.,Refratechnik Cement GmbH
Proceedings of the Unified International Technical Conference on Refractories, UNITECR 2013 | Year: 2014

As response to frequent wear by clinker melt attack on the elastifying component of magnesia bricks used in cement rotary kilns, a novel brick generation was created. By introducing the alumina-free mineral forsterite into the brick structure, the desired thermomechanical properties are combined with advantageous thermochemical behaviour. This new type of magnesia forsterite brick is characterised by a superior resistance to cement clinker melt attack and increased alkali resistance. Thanks to the adjusted amount of iron oxides and silica, this brick facilitates coating build-up by formation of magnesium silicates by reaction between the brick’s forsterite component and calcium silicates from the kiln feed. © 2014 The American Ceramic Society.

Groger P.,Refratechnik Cement GmbH | Klischat H.-J.,Refratechnik Cement GmbH | Puntke S.,Refratechnik Cement GmbH
Cement International | Year: 2017

The sales of cement, lime, steel and aluminium continue to provide an indication of the wealth of society. Together with some other industries their production stands at the start of the value-added chain and, as energy-intensive industries, they are always trying to reduce the use of energy without compromising the properties and quality of the products. The characteristics variables here are essentially the CO2 emissions, the carbon footprint and the energy efficiency. Numerous process engineering measures have been taken in the past to lower the energy usage. Moving the calcination of the limestone to the preheater, the use of a pre-calciner or the use of alternative, biogenic, raw materials and fuels can be mentioned here as examples. Efficiencies were achieved that are exemplary for thermal processes. Refractory products, which are located further along the value-added chain, are indispensable for the production of cement and lime [1]. The installation of thermally insulating refractory bricks in rotary kilns and the backing of brickwork with insulating materials have therefore also been known for a long time [2 to 4]. However, new developments offer further potential for lowering the use of energy and increasing the energy efficiency still further. Processes are coming increasingly to the fore that were formerly not considered because their energy-saving potential seemed low but will have to be taken into account in the future. This includes, for example, the heating procedure after a kiln stoppage. The examples of new developments in refractory technology that are described in this article are representative of the intensive interchange between customers and refractory developers and underline the potential for innovation.

Klischat H.-J.,Refratechnik Cement GmbH | Zielinski U.,Refratechnik Cement GmbH
Cement International | Year: 2010

The progressive use of secondary fuels in the cement industry has also increasingly necessitated the development of the requisite refractories. This paper gives an overview of recent developments in the basic, non-basic and monolithic refractory products used to cope with the thermochemical stresses that act on the linings in cement kiln systems. The combined efforts of cement producers and refractory suppliers have meant that the use of secondary fuels has had no significant negative influence on the performance of the linings [1].

Groger P.,Refratechnik Cement GmbH | Krause A.,Refratechnik Cement GmbH
Cement International | Year: 2013

In the course of the historical development of cement plant technology, Refratechnik Cement GmbH at Göttingen created in the 1960s a mechanically optimized basic refractory brick with high pyroplasticity for application in large diameter rotary kilns. Even today, this brick grade, that is well-known under the name PERILEX®, belongs to the core products of the company. Analyses carried out throughout the world show that 74% of the refractory consumption, in average of various kiln systems, takes place in the rotary kiln and that a substantial part thereof is fully or in part due to mechanical influences. Under the impression of steadily increasing thermochemical loads, an increased number of kiln revolutions and also of governmental regulations imposed concerning environmental protection, Refratechnik developed the first chrome orefree, superelastic magnesiaspinel brick grade that was launched as ALMAG® A1 in 1996. Quite soon, this brick grade proved to be a genuine trouble shooter in rotary kilns, particularly when serving as refractory lining in the coating-free upper transition zone and in the area of the second tyre. Triggered by the increased use of alternative fuels, cement raw materials and also lower-grade primary energy resources, the chemically/mechanically induced wear to traditional refractory materials kept on increasing dramatically in the subsequent years. Again, Refratechnik Cement GmbH responded to this scenario by further developing existing products accordingly and expanded its range by a complete product line comprising the AF products ALMAG® AF, TOPMAG® AF, REFRAMAG® AF as well as the highly elastif ied A1 and CF products ALMAG® A1, TOPMAG® A1 and PERILEX ® CF.

Thomas S.,Refratechnik Cement GmbH | Beimdiek K.,Refratechnik Cement GmbH
Cement International | Year: 2014

Thermal recycling of waste coupled with the explicit use of specially selected secondary fuels presents operators with a number of challenges, not only in terms of process engineering. For some years now, signs of corrosion have been observed in the preheater tower in many plants, and this has necessitated a response from the operators. In the field of wear materials, Refratechnik Cement GmbH offers a wide range of matched solutions for both rotary kilns and static plant units. However, an optimum refractory lining for plant units is not just a matter of selecting the wear material; a suitable insulation material is also of great significance in order to prevent corrosion of the steel shell. Thus, when planning new linings and repairs, it is vital to be aware not only of the process parameters, but also of the local aspects such as temperature and wind conditions, and take due account of these.

Klischat H.-J.,Refratechnik Cement GmbH | Vellmer C.,Refratechnik Cement GmbH | Wirsing H.,Refratechnik Cement GmbH
ZKG International | Year: 2013

Regarding their performance characteristics in cement rotary kilns - particularly under thermomechanical loads - magnesia chromite bricks of the PERILEX® 80 type have set new standards. Although this brick grade already features a reduced chrome ore content, the formation of chromates under corresponding conditions cannot be excluded. With PERILEX® CF a product is available now, which exhibits the same positive thermomechanical properties as PERILEX® 80, but without the use of chrome ore. Further improvements were also achieved by increasing infiltration resistance, coating formation, and even thermoplastic stress relaxation. The concept of the chrome ore free PERILEX® has been confirmed in numerous applications, so that a new, innovative and future-proof basic product for the lining of cement rotary kilns is available now.

Beimdiek K.,Refratechnik Cement GmbH | Klischat H.-J.,Refratechnik Cement GmbH
Proceedings UNITECR 2011 Congress: 12th Biennial Worldwide Conference on Refractories - Refractories-Technology to Sustain the Global Environment | Year: 2011

Corrosion by alkali attack has become one of the major reasons for refractory wear. This paper shows the monolithic development to counteract this corrosion mechanism by a graded alkali resistance which offers a superior thermochemical performance as a function of temperature up to 1500 °C. Furthermore the positive influence of various installation techniques is shown which contribute to a superior refractory performance of these monolithic linings in cement kiln systems.

Zielinski U.,Refratechnik Cement GmbH | Kassau K.,Refratechnik Cement GmbH
ZKG International | Year: 2014

The kiln hood of a rotary kiln in a cement plant connects the hot area of the kiln with the clinker cooler. The continuously increasing capacities of modern cement plants also gave rise to larger kiln hood volumes, which require specially engineered refractory concepts, too. Apart from alkali attack and salt infiltration, growth effects induced by raw materials also play a considerable role with products based on andalusite. A frequently heard argument against basic linings is the expansion behavior of magnesia spinel bricks mentioned previously, as well as their higher thermal conductivity compared with alumina products. Hereby, the bricks rest over their entire width on the tongue of the adjoining brick.

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