Published 21st May, 2024 by Catherine Hill
The international refractories manufacturer RATH recently conducted a broad-based comparative corrosion study to investigate the effects of hydrogen on the refractory materials used in hydrogen-based direct reduction plants and which ones withstand the changed stresses particularly well – and gained groundbreaking findings. High Alumina Bricks Properties
Global steel production contributes significantly to global warming and climate change. However, there are promising approaches towards decarbonization in the steel industry and therefore more sustainable steel production: Hydrogen-based direct reduction plants are going to play an important role in the future.
The use of hydrogen in steel production means that the refractory material is exposed to different stresses. How do these new operating conditions affect corrosion behaviour and corrosion dynamics? How strong is the influence of temperature? And how do refractory materials have to be formulated to meet the individual requirements of a customer, thereby enabling optimal and cost-effective performance in direct-reduction systems? To this end, RATH has carried out comprehensive comparative corrosion tests and recently presented pioneering study results at the 5th Freiberg Refractory Symposium, which took place from 22–24 April in Freiberg, Germany. Investigations into aluminosilicate and high-alumina refractory materials
In the course of this study, RATH’s extensive non-basic product portfolio with a composition of 40–99 % Al2O3 was exposed to an H2 atmosphere. Samples of lightweight refractory bricks, dense bricks, monolithic products, mats made of high-temperature wool and vacuum-formed parts were evaluated. The corrosion tests were carried out at the German Institute for Refractories and Ceramics (DIFK).
The temperature exposure was 1250°C and 1400°C in a 100-% H2 atmosphere, with an exposure time of 200 hours. In addition, aging at 1100°C under a typical mixed gas atmosphere was performed specifically for use in direct reduction plants. Corrosion was assessed by determining the mass loss in order to be able to make statements about temperature dependency and corrosion rate. In addition to determining the physical properties, further chemical analyses and X-ray diffractometry measurements were carried out before and after exposure to provide further information on phase stability and new mineral formation.
Important findings from the study:
In summary, RATH’s study results are highly relevant for future material selection in the respective application. The targeted further development of refractory materials and systems is particularly important for the transition to direct-reduction plants with additional hydrogen admixture and the goal of producing steel in a completely climate-neutral way in the future.
Alumina Silica Fire Brick http://www.rath-group.com/metals