Predicting the long-term refractoriness of high-alumina refractory concretes under high thermal load conditions, with particular emphasis on impurities from secondary raw materials
Project title
Predicting the long-term refractoriness of high-alumina refractory concretes under high thermal load conditions, with particular emphasis on impurities from secondary raw materials
Name of Beneficiary/Beneficiaries
Association of Refractory Materials' Producers
Łukasiewicz Research Network – Institute of Ceramics and Building Materials
Forschungsgemeinschaft Feuerfest e.V.
Hochschule Koblenz
Name of programme
International programmes
Competition
CORNET 29
Project value
PLN 2,134,271.23
Funding value
PLN 1,135,936.28
Project delivery period
from 02.01.2021 to 30.04.2023
See the results of our work
The head of the research team from Łukasiewicz ICIMB, dr hab. J. Podwórny, presents the project results at the "20th International Conference on Refractory Materials: Manufacturing, Testing Methods, Application" in Wisła (24-26.05.2023) during the special session "Monolithic Materials – International Cooperation." Representatives of the project team gave presentations under one common title: An insight into the impact of impurities, typical in secondary raw materials, on the behaviour of high alumina castables
Project manager dr inż. Jerzy Czechowski presenting the paper The refractory industry in the EU - as it stands and in view of future expectations at the session of the 9th International Congress on Ceramics during the "Ceramics in Europe 2022" conference in Kraków, 10 – 14.07.2022 (presentation covered, among other things, the importance of recycling and the RefraPredict project).
What problem does our project solve?
Refractory monolithic materials, i.e. those that are not moulded and fired prior to insertion into a heating device but instead come in the form of masses and concretes with compositions ensuring high-temperature resistance, are gaining increasing interest from manufacturers and users. A key advantage of these materials is that their strength and resistance properties are shaped directly in the lining at the user’s facility during the heat treatment process, and their uniform form, free of joints common in moulded refractory linings, enhances their resistance to corrosion caused by destructive factors (e.g., alloy components, atmosphere). The goal of refractory material manufacturers is to provide users with materials that ensure appropriate durability under operational conditions. Achieving this goal requires the use of high-quality raw materials. In the EU, including Poland, high-quality raw materials are primarily supplied from China, and their availability is becoming increasingly scarce. At the same time, there is a growing focus on a closed-loop economy, prompting greater use of secondary raw materials. These secondary raw materials introduce impurities, which may negatively affect the thermomechanical properties of refractory materials. The project aimed to better understand the relationship between the composition of raw materials, the presence, and nature of impurities in the matrix, and the thermomechanical properties of monolithic corundum materials. It also aimed to provide manufacturers with guidelines for optimising the composition of refractory concretes to ensure the desired properties. The scope of the research is presented below:
Legenda:
Opracowanie modelowych betonów ogniotrwałych z systematycznie zanieczyszczaną osnową - Development of model refractory concretes with systematically contaminated matrix
Badania wpływu zanieczyszczeń na własności "na zimno" betonów modelowych - Study of the impact of impurities on the "cold" properties of model concretes
Skoncentrowanie się na preparatyce betonów modelowych – Focusing on the preparation of model concretes
Betony modelowe ze spinelem - Model concretes with spinel
Betony modelowe bez spinelu - Model concretes without spinel
Badania mikrostruktury, własności termomechanicznych i opracowanie metody badania prędkości pełzania w oparciu o koncepcję Norton'a-Bailey'a - Studies of microstructure, thermomechanical properties and development of a creep rate test method based on the Norton-Bailey concept
Skoncentrowanie się na strategii prowadzenia badań, które umożliwią lepsze przewidywanie maksymalnej temperatury pracy betonów modelowych i generalnie materiałów ogniotrwałych – Focusing on the research strategy that will enable better prediction of the maximum working temperature of model concretes and, in general, refractory materials
Opracowanie innowacyjnego urządzenia umożliwiającego równoczesne badanie wpływu gradientu temperaturowego i obciążenia mechanicznego - Development of a novel device enabling the simultaneous testing of the effects of temperature gradient and mechanical load
Badania własności wysokotemperaturowych betonów modelowych, w tym z zastosowaniem testu "wedge split" i metody monotonicznego ogrzewania - Study of the high-temperature properties of model concretes, including the use of the "wedge split" test and the monotonic heating method
Skoncentrowanie się na symulowaniu obciążenia termomechanicznego w próbkach modelowych betonów z kontrolowaną ilością zanieczyszczeń, podobnego do tego, jakiemu są poddawane materiały ogniotrwałe w warunkach pracy - Focusing on simulating thermomechanical loading in model concrete samples with controlled levels of impurities, similar to the conditions that refractory materials are subjected to during service
Wnioski będą identyfikować i definiować parametry krytyczne umożliwiające w sposób jasny przewidywanie zachowania ogniotrwałych materiałów monolitycznych z zanieczyszczeniami pochodzącymi z surowców wtórnych w rzeczywistych warunkach stosowania – The conclusions shall identify and define critical parameters that clearly predict the behaviour of monolithic refractory materials with impurities from secondary raw materials under actual operating conditions
The research focused on combinations of impurities that represented the most unfavourable conditions in terms of their impact on thermomechanical properties, particularly due to the formation of a liquid phase. However, the results showed that it is possible to determine impurity ratios that do not critically degrade thermomechanical properties. These findings shed new light on the potential for the deliberate use of secondary raw materials in the technology of monolithic refractory materials. It is feasible to maintain the properties of corundum concretes at a satisfactory level for industrial processes where they may be applied.
Furthermore, it was found that the grain growth process in the matrix of materials with active alumina bonding, which increases the mechanical strength of the tested materials, does not keep pace with the effects caused by the applied load. This is a valuable insight for manufacturers and users, indicating that such materials, with active alumina bonding, should not be used in applications where high mechanical loads occur during the heat treatment of the installed lining.
Who will benefit from the project's results?
The results of the project will benefit refractory material manufacturers, particularly small and medium-sized enterprises that do not produce fired materials but focus on the production of refractory masses and concretes. The guidelines included in the conclusions will enable the development of corundum concrete formulations using secondary raw materials while ensuring properties that meet user expectations. All members of the Association of Refractory Materials' Producers (SPMO) received reports from the project. Moreover, the research results were published (in “Open Ceramics”) and presented in papers at national and international conferences (including the “International Colloquium on Refractories ICR 2022”, “Ceramics in Europe 2022”, the “19th and 20th International Conference on Refractory Materials: Manufacturing, Testing Methods, Application” in 2022 and 2023, and the Unified International Technical Conference on Refractories (UNITECR 2023) 18th Biennial Worldwide Congress on Refractories in Frankfurt, Germany).
The conclusions from the research will also be useful for suppliers of refractory secondary raw materials and users of refractory materials, particularly regarding guidelines for the heat treatment of linings.