Waelz slag-based construction ceramics: effect of the trial scale on technological and environmental properties

Abstract

The construction industry has already begun the transition to circular economy and intensive research has been conducted over the last decades at laboratory scale to assess the potential use of waste in ceramic applications. However, industrial trials to prove its scale up have been performed to a lesser extent. This work studies the effect of trial scale on the technological and environmental properties of high quality ceramic products incorporating Waelz slag (WS), an industrial by-product from the recovery of electric arc furnace dust. To this aim, three groups of ceramics have been produced varying the WS content and the process parameters, moulding water and pressure, at laboratory and industrial scale. Preliminary laboratory scale tests were used to optimize WS content and process conditions using the software GAMS (General Algebraic Modeling System). Optimum ceramic products were processed at both laboratory and industrial scale and tested for their technological and environmental properties. Results from the laboratory and industrial trials were compared to evaluate the scale effect on the ceramic properties. The introduction of WS in clay bricks seems to be easily scaled-up for additions of WS ≤ 10wt%, but higher percentages of WS promotes relevant differences in the properties of the laboratory and industrial bricks.