GRK 2802: CHARACTERIZATION OF COMMERCIAL MgO-C REFRACTORY BRICKS BASED ON MgO-C RECYCLATE WITH VARYING TOTAL CARBON CONTENTS

Abstract

In light of the increasing focus on the recycling of refractories, the properties of commercial MgO-C refractory bricks containing MgO C recyclate are of significant economic and ecological importance. It is essential to consider that incorporating MgO-C recyclate can lead to increased variation in the material composition and, consequently, in the properties of MgO-C grades. In the present study, two commercially available grades of MgO-C bricks containing 47.5 wt.% MgO-C recyclate were characterized. The MgO-C recyclates of both grades were taken from different sources and differed particularly in their carbon content, which resulted in different total carbon contents of both MgO-C brick grades. In addition to determining fundamental properties of both MgO-C brick grades (e. g., total carbon content, bulk density, open porosity, and cold crushing strength), XRD analysis, refractoriness under load (RUL) tests, and four-point bending tests at 1000 °C in an argon atmosphere were conducted. A lower total carbon content resulted in an increased bulk density, higher thermal expansion and increased strength. Compared to a commercial MgO-C grade made from entirely fresh raw materials, the results of the RUL and bending tests revealed no detrimental effects through the incorporation of MgO-C recyclate. Despite different total carbon contents, both MgO-C grades with recyclate exhibited improved refractoriness in the RUL tests compared to the material containing only fresh raw materials.