Challenges and Performance of Filter Dusts as a Supplementary Cementitious Material.

Global industry relies on a linear approach for economic growth. One step towards transformation is the implementation of a circular economy and the reclamation of anthropogenic deposits. This study examines two filter dusts, one German and one Argentinian, from the production of calcined clays, representing such deposits. Investigations and comparisons of untreated and calcined filter dust and the industrial base product pave the way for using waste product filter dust as supplementary cementitious material (SCM). In the future, some twenty thousand tons of contemporary waste could potentially be used annually as SCM. The results confirm the suitability of one material as a full-fledged SCM without further treatment and a measured pozzolanic reactivity on par with fly ash. Sample materials were classified into two groups: one was found to be a reactive pozzolanic material; the other was characterized as filler material with minor pozzolanic reactivity. Additionally, important insights into the physical properties of oven dust and heat-treated oven dust were obtained. For both material groups, an inversely proportional relationship with rising calcination temperatures was found for the specific surface area and water demand. The impact of the calcination temperature on both the particle size distribution and the potential to optimize the reactivity performance is presented.