Production of Refractory Bricks through Combustion Synthesis from Metallurgical Wastes and the Thermo-Physical Properties of the Products

Industrial symbiosis is one of the key approaches to meet sustainable and low carbon production targets. Thus, through circular approaches, it is possible to reduce the use of natural crude materials and make production processes waste-free in the metallurgical industry. The purpose of this study was to study the possibility of using various metallurgical waste and low-grade semi-finished products, which do not have a direct application area, in the production of heat-resistant carbon-containing refractory bricks through the combustion synthesis (CS) method. In the experiments, used metallurgical wastes were wet filter cake (FC), sludge (S), and refractory magnesite scrap (MS) while semi-products were rich and poor dust of chrome spinel (Cr-S). Simultaneously with the experiments, thermochemical simulation studies were carried out using the HSC Chemistry 6.12 to predict the thermodynamic properties of the reactions and possible reaction products. Thermal conductivity coefficients were determined in products in terms of thermal properties of composite samples, they were between 0.511 and 1.020 Wm/K. The phase compositions of the produced samples were determined via XRD technique. The TG-DTA technique was used to characterize thermal behavior of products. In addition, mechanical properties were determined by compression strength test. As a result of experiments, it was observed that Cr-S-rich-based samples showed a promising result in comparison to others: increasing amount of useful carbide phases were formed and demonstrated a high value of mechanical properties. Compression strength was increased from 2.7 MPa (sample 4) to 15.8 MPa (sample 1) with increasing chromite-containing phases in the green samples.