Imerys Refractory Minerals launched a new product called Randalusite™ Premium, which is the highest quality andalusite available on the market. Indeed, Randalusite™ Premium is the purest product in terms of chemical and mineral composition. It allows refractory producers to use andalusite applications where high creep resistance are mandatory. A study comparing the performance of different types of andalusite raw materials was presented during the 2016 Aachen Refractory Colloquium. In this study, a broad range of andalusite was characterised, in particular regarding chemical and mineralogical composition. Specific attention was given to the distribution of impurities across the different size fractions.
Refractory bricks and castables were produced from each type of andalusite on a laboratory scale in order to establish a correlation between the raw material purity and the refractory performance. Thermo-mechanical properties such as Refractoriness under Load (RuL) and Creep in Compression (CiC) were investigated, with a particular focus on the impact of impurity level, its enrichment in the matrix and its influence on the microstructure.
The outcome of the study allowed Imerys Refractory Minerals to launch Randalusite™ Premium. Its alkalis are lower than 0.35% and its alumina higher than 60%. It is obtained by advanced processing designed for high performance bricks & castables thus opening doors to new applications for andalusite based refractory solutions. Find out more about Randalusite™ Premium