Preparation and characterization of ceramic foams from chromium slag and coal bottom ash

Abstract Chromium slag and coal bottom ash (CBA) were used as raw materials to prepare the closed-pore ceramic foam. The effect of chromium slag content on the bulk density, compressive strength, pore structure, and crystalline phase of ceramic foams was systematically studied. The results show that a small amount of chromium slag incorporation significantly promotes the formation of pores, and the bulk density gradually drops with the chromium slag content increase. A good correlation between compressive strength and bulk density was observed. Furthermore, the compressive strength was also affected by the pore structure (i.e., pore size and distribution). Ceramic foam with 30 wt% chromium slag was found to possess excellent properties, such as lower bulk density (0.191 g/cm 3 ), superior compressive strength (1.3 MPa), smaller pore size (0.73 mm) and an extremely low leached concentration of Cr (0.004 mg/L).