Circular Economy for Municipal Solid Waste Incineration Bottom Ash (MSWIBA) Management in Mortars with CSA and CEM I, MSWIBA Glassy Phase, and DTG

The increase in frequency and intensity of natural disasters is related to the changing global average temperature. Reducing greenhouse gas emissions and the extraction of natural resources is one of the solutions proposed by the European Green Deal and the 17 Sustainable Development Goals (SDGs) approved by the United Nations. The article presents research on municipal solid waste incineration bottom ash (MSWIBA), which is the basis for its circulation in the idea of the circular economy. The MSWIBA study presents differential thermogravimetry (DTG), glassy phase, and mortars using CSA and CEM I. The management of MSWIBA contributes to reducing greenhouse gas emissions and the extraction of natural resources.

Nano Silicate Ceramic Coating Material Applied to Increase the Emissivity and Efficiency of Primary Reformer Radiant

Nano silicate ceramic material prepared in this research for coating the walls of the primary reformer unit in the state company of fertilizers. It is applied to increase the emissivity and thermal efficiency to improve the properties of insulation materials. Moreover, it is increasing the working operation time for catalyst tubes and reducing the carbon dioxide emissions. Nano coating materials were prepared by using different refractory materials that include silica, filed spar, alumina, manganese dioxide and magnesium oxide. The preparation method was done by, calcination and firing these materials then crashing to get extremely fine powder. The results show that coating materials consist mainly from quartz crystalline and glassy phase structure with a grain size of 158 nm and penetration between 10 to 20 mm when using different concentration 0.5 to 1.0 % for total mix. The emissivity of primary reformer insulation materials was increased with 30 % comparing with insulation materials without coating.

Microstructure Evolution Mechanism of Geopolymers with Exposure to High-Temperature Environment

The investigation on geopolymers has intrigued broad interests in the past decades, due to the requirements for the recycling of aluminosilicate solid wastes, such as red mud, slags, sludges and demolished concrete. Previous studies have demonstrated the feasibility of reusing this Aluminosilicate as a resource to prepare cementitious materials and indicated their promising properties at ambient temperature. However, when this material was exposed to high temperatures, especially above 1000 °C, the microstructure evolution mechanisms were not systematically investigated. In this study, the microstructural evolution process of metakaolin-based K geopolymer (molar ratio of K:Al:Si was 1:1:4) is investigated. The crystalized leucite originated from the geopolymer precursor was detected above 1000 °C. The SEM results indicate that the microstructure of the geopolymer before heating was composed of non-reacted metakaolin with a typical layered structure and reacted amorphous binder phase. As the geopolymer heated to 1000 °C, the microstructure of the geopolymer changed to a porous structure with an average pore size from 10 to 30 μm. When the heating temperature reached 1100 °C, the pores started to close along with the leucite crystallization process. As the heating temperature reached 1200 °C, most of the pores were closed. The TEM results show that the microstructure of the geopolymer, after being heated to 1400 °C, was composed of an amorphous glassy phase and crystallized leucite phase. The crystallized leucite grains originated from the nano-sized crystal nuclei, with an average size of 2–3 nm. The TEM-EDS results indicate that the chemical composition of the glassy phase was complicated. It varied from area to area because of the movement and uneven distribution of K.

Utilization of Porcelain Tile Polishing Residue

The research focuses on the properties of by-products formed in the production of porcelain stoneware: polishing residue and residue of the mixture-preparation shop. The polishing residue consists of glassy phase (80%), quartz (14%), mullite (5%). Residue of the mixture-preparation shop consists of quartz (~ 18%), muscovite (~ 6.9%), kaolinite (~ 20.5%), calcium-sodium feldspar (~ 51.4%), diopside (~ 2.98%). Polishing residue occurs when polishing porcelain stoneware to create a glossy surface and when polishing the side faces of porcelain stoneware to obtain accurate tile geometry. The particle size of the polishing residue is less than 0.2 mm, and the residue of the mixture-preparation shop is less than 40 microns. Residue of the mixture-preparation shop is formed when cleaning equipment: mills, mixers, slipways, etc. The ways of utilization of by-product are follows: as a filler for the silicate production; for polymer-cement, water-dispersion and oil paints; as a filler for the production of roofing materials, bituminous roofing mastics based on organic binders; raw materials for the production of foam glass materials and products.

Felsite in Ceramic Materials Production

This project is devoted to the study of the felsite properties for the purpose of its application in the production of various types of fine ceramics: ceramic tiles, acid-resistant tiles, aluminosilicate proppants, etc. Felsite is a mixture of quartz (about 40%) and feldspars. In the compositions of ceramic masses, felsite can play the role of both nonplastic due to the quartz content, and flux due to the content of feldspars, that reduces the amount of mixture components. When felsite is fired, the melt appears at a temperature above 950°C. The felsite has a sintering effect when fired at a temperature of 1000°C. Glass phase enriched with SiO2 ensures the absence of material deformation after firing. Also, glassy phase provides high-acid and chemical resistance of materials based on it. In addition, after firing above 1150°C, felsite has a light color, which is a great advantage in comparing it as a melt with other iron-alkali-containing materials. Ceramics based on felsite does not require the use of opacified glazes.

The potential of chemical bonding to design crystallization and vitrification kinetics

Controlling a state of material between its crystalline and glassy phase has fostered many real-world applications. Nevertheless, design rules for crystallization and vitrification kinetics still lack predictive power. Here, we identify stoichiometry trends for these processes in phase change materials, i.e. along the GeTe-GeSe, GeTe-SnTe, and GeTe-Sb2Te3 pseudo-binary lines employing a pump-probe laser setup and calorimetry. We discover a clear stoichiometry dependence of crystallization speed along a line connecting regions characterized by two fundamental bonding types, metallic and covalent bonding. Increasing covalency slows down crystallization by six orders of magnitude and promotes vitrification. The stoichiometry dependence is correlated with material properties, such as the optical properties of the crystalline phase and a bond indicator, the number of electrons shared between adjacent atoms. A quantum-chemical map explains these trends and provides a blueprint to design crystallization kinetics.

Synthesis and Properties of Thermotropic Copolyesters Based on Poly(ethylene terephthalate) and 4′-Acetoxy-4-biphenyl-carboxylic Acid

A series of novel copolyesters based on polyethylene terephthalate (PET) and 4′-hydroxy-biphenyl-4-carboxylic acid (HBCA) was obtained by melt polycondensation of bis(2-hydroxyethyl) terephthalate and 4’-acetoxybiphenyl-4-carboxylic acid (ABCA) as co-monomers with Sb2O3 as a catalyst. Using this synthetic procedure, a set of copolymers containing 20–80 mol% of HBCA units was prepared. According to NMR spectroscopy, the copolymers were of random composition. Copolyesters comprising 60–80 mol% of HBCA possessed increased heat resistance and formed nematic melts at 270 °C and higher. The liquid crystal (LC) phase formation was accompanied by transition to non-Newtonian characteristics of the melt flow, as well as an equalization of storage and loss moduli values. According to XRD and polarizing microscopy, the LC glassy phase of the copolyesters coexists with crystalline regions of poly-(4’-hydroxy-4-biphenylcarboxylate), non-melting up to 400 °C and above. The mechanical characteristics of these LC copolyesters showed similar or better values than those of well-known LC polymers. These novel copolyesters can be useful in obtaining heat-resistant materials with an ordered structure and, as a consequence, improved performance.