DISPOSAL OF CERAMIC CASTING MOLDS AS A FILTERING MATERIAL

Abstract

Wastes generated by metallurgical and steelmaking plants constitute a significant volume and represent potential for application as filtering media for the treatment of industrial wastewater. This article presents the results of studies of granular filtering material obtained from crushed ceramic molds, which are technological wastes from casting using burnt models at an industrial facility in the South Ural Region. The casting molds are made from local fireclaykaolin raw materials and are fired at a temperature of 900–1000 °С for 40–60 minutes. When the casting is removed, the mold is broken and discarded. The utilization of this waste as a granular filtering material or adsorbent is the primary objective of this study. For this purpose, the samples have been crushed and sieved, and the material samples have been tested for compliance with the requirements for granular filtering materials. The sorption properties are studied on samples of two fractions of 0.315–0.8 mm and 0.63–1.4 mm. The chemical composition of the samples are studied using energy-dispersive spectrometry; the silicate modulus of the material has been found to be 0.75, which is characteristic of adsorbents. Morphological analysis of the grain surface, performed using scanning electron microscopy, showed high roughness and porosity of the material, which decrease with decreasing grain size. The material samples showed high mechanical resistance. However, low chemical resistance of the material in acidic and alkaline environments has been observed. Fourier-transform infrared spectroscopy has shown the similarity between the spectra of the granular filtering material samples obtained from crushed ceramic forms and those of Absorbent AS, indicating that they belong to the same group of materials – silicates.