Synthesis of Ceramics in Different Colors from Industrial Waste

The synthesis of arsenic-free ceramics from industrial waste is studied. Samples of waste containing siliceous material passed the exploitation leap-guard layer shift reactor whose main oxide is -Al2O3 and, with the addition of natural raw materials and pure oxide, arsenic-free ceramics were synthesized with thermal and electrical properties related to the main phase of spinel group minerals; solid solutions were also formed in the process of synthesis. Insulating properties were established by successive heating and cooling of the specimen for six cycles. Electrical insulating properties were established by the method of resistance to arcing. The relative density was determined by hydrostatic method and diffusion lines of molecules at the main phase were characterized by X-ray diffraction analysis. The experimental procedures followed in this study allowed mixing on a molecular level due to the small dimensions of the crystallite which in turn explains the relatively high density. 1. Introduction The wastes from our daily household, commercial activities, and industrial operations are treated at sewage treatment plants and most of the sewage sludge is landfilled after reducing the volume. Rapid growth of industrial activities and urbanization in recent years led to increase of wastes and difficulties in securing sites for landfill disposal. Thus, the conversion of sewage sludge and processing of raw materials into resources are an emerging research topic area. To date, catalysts are used in the petroleum industry to refine processes such as the catalytic cracking, catalytic reforming, desulphurization, and the production of petrochemicals dealkylation processes. Silicate materials are also used as adsorbents and molecular sieves in the processes of gas desulphurization [1]. Several technologies have been developed to use effectively sewage sludge. In Russia, for example, colored glass (Sigran) is produced from condensed sewage sludge phosphorus. The composition of the slag system includes CaO, Al2O3, and SiO2 [2]. The molten glass crystallizes at 950°C. X-ray diffraction analysis shows that the main phases are α- and β-wollastonite and fluorite. The pigments used include Cr2O3, Co2O3, Cu2O, NiO, and Sb2O3 [3–5]. Green color ceramics have been synthesized from slag directly from the furnace metallurgical furnaces [5–7]. The chemical composition of slag was in %e: SiO2—50,6; CaO—14,9; MgO—4,4; MnO—15,6; Na2O + K2O—3–5,5; Al2O3—8 ÷ 10; FeO—0,3 ÷ 0,6; S2？—0,6 ÷ 12. Up to now, a number of reports have been published on glass-ceramics using waste materials