Institute of Mineral Engineering

Aachen, Germany

Institute of Mineral Engineering

Aachen, Germany
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Neumann A.,Institute of Mineral Engineering | Wilsmann W.,Institute of Mineral Engineering | Conradt R.,Institute of Mineral Engineering
Glass Technology: European Journal of Glass Science and Technology Part A | Year: 2011

The removal of noxious and air polluting substances from exhaust gases has become a routine procedure in the glass industry. Nevertheless process control is still based on empirical data and on the experience of the plant operators. In the past, the occasional and unexpected occurrence of aggressive fluxes in the electrostatic precipitators (e-filters) has bothered operators. This is unsatisfactory since the occurrence could not be attributed in a clear way to any unfavourable boundary conditions. This paper presents investigations of the thermodynamic and kinetic conditions in Na 2O-H 2O-SO 2-CO 2-N 2-containing flue gases below 500°C. The investigations are particularly focused on the formation of liquid and solid sodium pyrosulphates and sodium bisulphates, as well as on their occurrence and avoidance inside the flue gas filters. It is shown that the formation is strongly dependent on the oxygen and water vapour partial pressure of the system. The measurements show that many different liquid mixed phases are formed within this system at low water vapour pressures. These phases can be avoided by raising the saturated vapour pressures above 200 mbar.

Becker E.,Institute of Mineral Engineering | Prange A.,Institute of Mineral Engineering | Conradt R.,Institute of Mineral Engineering
Materials Research Society Symposium Proceedings | Year: 2010

This paper presents the Chemical-Mechanical Polishing of optical and fine-optical glasses, which is employed to fulfill the optical requirements for the surfaces of optical lenses. We present the effect of chemical interactions in the polishing process of optical lenses and show how these interactions can be influenced by the additions of certain chemicals. Furthermore, we present a thermodynamic simulation tool, by which these interactions can be modeled. Thus it is possible to understand the chemistry in the suspension and to simulate recent polishing processes in advance, with new additives or with various intrinsic glass ions from different glasses. © 2009 Materials Research Society.

Schusser A.,Institute of Mineral Engineering | Pascual M.J.,CSIC - Institute of Ceramics and Glass | Prange A.,Institute of Mineral Engineering | Duran A.,CSIC - Institute of Ceramics and Glass | Conradt R.,Institute of Mineral Engineering
Ceramics International | Year: 2013

In this work, the characterization of a soldering system with wollastonite as filler added as powder to the powdered base glass is shown. A soldering system consisting of the base glass and a coexisting crystalline phase is created which is then pressed to pellets and sintered to maximum density. Wollastonite increases the thermal expansion coefficient of the base glass after sintering the samples. In the present paper, the sintering behavior of the soldering system and possible interactions between glass and filler are analyzed. Also, density and porosity after sintering and the resulting crystalline phases are characterized. The mixtures with wollastonite contents up to 30% showed suitable sintering behavior and good density (low porosity). From 40% wollastonite on, the sintering of the samples was not satisfying and porosity was still high after sintering. The main crystalline phases were anorthite, wollastonite and pseudowollastonite, which occurred in all samples. This shows that all three phases are coexisting phases of the glass composition. © 2012 Elsevier Ltd and Techna Group S.r.l.

News Article | March 11, 2016

The organizers of the International Glass Fiber Symposium, taking place from 17–19 October 2016 in Aachen, Germany, have released details of the event. According to the Institut für Textiltechnik of the RWTH Aachen University (ITA) and the Institute of Mineral Engineering of RWTH Aachen University (GHI), the aim of the conference is to build a bridge from the manufacturing of the glass fibers to the composite material users covering every intermediate step. The conference will feature producers as well as operators to exchange information on the latest developments in the field. Problems can be discussed from the producers as well as the operator’s point-of-view. ‘Many conferences are aligned exclusively to topics like 'carbon fibers' or generally focus on fiber composite structures,’ the organizers said in a press release. ‘The topic 'glass fibers' mostly takes a backseat and is never focused on its own although the market of high modulus fibers consists up to 90% of glass fibers. This is the reason why the conference offers an ideal ground to cover the whole topic from raw material all the way to the end-product.’ This story uses material from RWTH Aachen University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.

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