Kurzfassung

The main problem for SMEs in the refractory sector, on which this CORNET project focuses, is that refrac- tory producers want to, need or must increase the use of secondary raw materials. They may be forced to do so by economic, ecologic or even legal causes. It is unclear, however, how impurities which are being carried over into refractory materials from secondary raw materials influence the behaviour of those re- fractory materials, either during the processing state or during their use in...The main problem for SMEs in the refractory sector, on which this CORNET project focuses, is that refrac- tory producers want to, need or must increase the use of secondary raw materials. They may be forced to do so by economic, ecologic or even legal causes. It is unclear, however, how impurities which are being carried over into refractory materials from secondary raw materials influence the behaviour of those re- fractory materials, either during the processing state or during their use in high temperature environ- ments.
The research objective of this CORNET project is to increase the knowledge about the influence of small amounts of impurities (Σ < 2 wt.-%) from secondary raw materials onto the processing behaviour (worka- bility, setting, hardening) and the high temperature behaviour/performance of monolithics.
The research shall be carried out using primary high alumina raw materials that will be selectively “impuri- fied” using typical elements found in secondary raw materials. Those raw materials shall be processed into monolithics. Extensive examination of the nature/amount of the impurities and the processing and high- temperature behaviour is expected to reveal the correlation between the two. These examinations will be facilitated by a new testing setup, which will be designed to simulate the exact conditions under which monolithics are subjected in use, i.e. a temperature gradient and thermal stress concurrently (strain or stress-controlled loading). The high-temperature behaviour shall be examined using standardised (refrac- toriness under load, creep in compression) and non-standardised (Method of Monotonic Heating MMH, RFDA, FE-SEM) methods.
The research also aims at improving the definition of “refractoriness”. What is understood as a limiting temperature for the use of a refractory product is indeed a temperature range, in which melt phases are being formed and refractories undergo a transition from brittle to ductile behaviour. These effects are ac- tually able to drastically improve the high temperature behaviour of refractories. However, they are not well understood and the effects of impurities from secondary raw materials onto this behaviour is widely unknown.
The main result will be new knowledge about the influence of impurities from raw materials on the behav- iour of refractories, and a new testing setup to test refractories in conditions under which they are sub- jected in use. A further result will be a better definition of “refractoriness”.
The new knowledge shall enable SMEs from the refractory sector to use more secondary raw materials, while guaranteeing the performance of the refractory materials they produce.» weiterlesen» einklappen