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The incombustible portion of coal that remains after burning is known as bottom or fly ash, and it has a detrimental influence on the environment. One of the possible alternatives for reducing the amount of ash deposited in landfills might be the production of useful glass–ceramic from vitrified fly ash. Glass–ceramic was synthesized using fly ash from the thermal power plant "Nikola Tesla" and fluxing additives. Sinter crystallization of the parent glass resulted in glass ceramics. The glass was created by melting a combination of coal fly ash (CFA), Na2CO3, and CaCO3 at T = 1500 °C and quenching the melt in the air. Glass powders were sintered at temperatures 850 and 900 °C. The resulting glass–ceramics were characterized microstructurally, physically, and mechanically. The cavitation erosion of samples was evaluated. The cavitation rate was 0.015 mg/min for the sample sintered at 850 °C and 0.0053 mg/min for the sample sintered at 900 °C. The leaching of heavy metals in glass–ceramic samples was determined using Toxicity Characteristic Leaching Procedure. A low concentration of heavy metals in the leaching solution showed that heavy metals were successfully incorporated in the glass matrix and that obtained glass–ceramics are ecologically safe for usage. Both samples exhibit good resistance to cavitation erosion, suggesting their potential as possible replacements for structural ceramics commonly employed components of hydraulic machinery.

In order to preserve the environment, the strategy of economic development in the world is based on the use of waste as a raw material for obtaining new products. Waste can be used in the same industry in which it was produced or in other industries. This paper presents an examination of the chemical durability of glass-ceramics obtained by sintering fly ash glass at characteristic temperatures (850 and 900°C). The chemical stability of the glass-ceramics was tested in three solvents, distilled water, HCl (0.01 mol/dm3) and NaOH (0.01 mol/dm3). The results indicate that the chemical durability of glass sintered at 900°C is slightly lower than glass-ceramic sintered at 850°C. The higher chemical durability of the glass-ceramic sintered at 850°C can be attributed to the presence of wollastonite, which was not detected in the glass-ceramic sintered at 900°C. The obtained glassceramics has a high chemical durability, with mass changes below 1%. FTIR and SEM analysis of the samples after dissolution revealed that there was no disruption of the structure.

The crystal growth rate of LiGe2(PO4)3 phase from lithium germanium-phosphate glass was studied. The glass have been homogenized using the previously established temperature-time conditions, which make it possible to remove volatile substances from the glass melt. The atomic absorption spectrophotometry (AAS) was used to determine the chemical content of the obtained glass and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth. The crystal growth rates were determined experimentally and theoretically.

Foam glass is a lightweight and high-strength material that can be used for thermal and acoustic insulation. Foam glass with suitable properties for use as an insulating material was prepared using waste flat glass, a glass waste not normally used for the production of glass foam, and sugar beet factory lime (S), a CaCO3-rich waste, as a novel foaming agent.Three mixtures were prepared: Glass powder mixed with S (FG-S), glass powder mixed with S and borax (FG-S-B), and glass powder mixed with S and water glass (FG-S-WG). The mixtures were homogenized, pressed into pellets in a hydraulic press, and foamed at 800 °C for 30 min. The prepared samples were characterized mechanically, thermally, and microstructurally. All samples exhibit very low crystallinity. FG-B has the lowest total porosity but much higher compressive strength than FG-S and FG-S-WG. In addition to the total porosity, the pore size distribution of the samples also has a strong influence on the compressive strength. FG-S-B has smaller pores compared to FG-S and FG-S-WG, where the intense foaming of S and water glass leads to the rupture of the pore walls and their coalescence. The thermal conductivity follows the same trends as the total porosity. FG-S and FG-S- WG have a thermal conductivity of 0.044 W/m.K and FG-B has 0.059 W/m.K. All samples have good thermal properties as insulators, but FG-S-WG has poor mechanical properties.

The crystal growth rate of LiGe2(PO4)3 phase from lithium germanium-phosphate glass was studied. The glass have been homogenized using the previously established temperature-time conditions, which make it possible to remove volatile substances from the glass melt. The atomic absorption spectrophotometry (AAS) was used to determine the chemical content of the obtained glass and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth. The crystal growth rates were determined experimentally and theoretically.

Waste glass can be transformed into a foam by addition of suitable substance (foaming agent) which generated gaseous products by decomposition or reaction at temperatures above its softening temperature (corresponding to a viscosity of 106.6 Pas). This paper provides a concise overview of the latest research in the field of improving the glass foam production process. Some of the possibilities for reducing the environmental impact of glass foam production are also presented. Some of the new production techniques, new foaming agents as well as the possibility of including other solid waste in the composition of glass foams are presented. At the end, the glass foam produced in the Laboratory for glass and ceramics, Institute for Technology of Nuclear and other Mineral Raw Materials, was shown.

This paper presents the effect of K2O content on phase composition of the nanocrystallized niobium germanate glasses. It was shown that the exothermal peak temperature, Tp, shifted toward the higher temperatures with increasing content of K2O. Such increase of K2O content causes a decrease of GeO2 content in the primary phases. The crystals below 100 nm were detected in the samples.

This paper shows the dissolution behavior of polyphosphate glass in demineralized water and 2% citric acid solution at temperatures: 15, 20, 30, 37 and 50 °C. The influence of the solvent type on the diffusion coefficients of the modifying cations, under static conditions, is also presented. The diffusion coefficients, determined from concentration profiles of the modifying cations, are calculated to be in the range of 0.27 to 350x10-14 m2/h for dissolution in demineralized water, and in the range of 3.6 to 148x10-12 m2/h for the dissolution in 2% citric acid solution. The values of activation energy of cations diffusion in demineralized water are in the range from 68.32 to 105.41 kJ/mol, while for 2% citric acid solution they are in the range from 39.28 to 55.34 kJ/mol.

Open loop glass recycling is a process where the glass is recycled into a new product. Glass recycling helps reduce landfill waste. Glass takes up significant space in landfills and does not decompose. In many countries, landfills are filling up faster than we can create new ones. Recycling glass reduces the volume of waste, and increases the lifespan of landfills. One of examples of open loop recycling of glass is glass foam produciton. Glass foam production is a process that involves the creation of a light-weight glass material with a foam-like consistency. This type of glass is made by mixing a foaming agent with glass powder and heating to temperatures where decomposition of a foaming agent and sintering of glass happens. This results in the creation of a material that is light, strong, and has thermally-insulating properties. Milled flat glass was mixed with sugar beet factory lime, a CaCO3 – rich waste wich has role of a foaming agent, in order to enter 5% CaCO3 in mixture and pressed at 20 MPa in hydraulic press. Raw pellets were sintered at 800 °C for 30 min. In obtained glass foam phase composition, pore size distribution, compressive strength and thermal conducitivity were determined. Glass foam is emerging as a flexible, cost-effective, and sustainable material that can be utilized in numerous applications to promote sustainable development. Its features such as high insulation capacity, lightweight, and durability make it an ideal material for a wide range of industries.

The main goal of agricultural production should be the production of a sufficient amount of agricultural products with the least possible impact on the environment. In traditional agricultural production, in order to obtain a satisfactory yield, artificial fertilizers are used, which have multiple negative impacts on the environment. Glassy fertilizers are a type of fertilizer that, at least according to previous research, do not have a negative impact on the environment and the same time the use of these fertilizers yields not less than when using traditional fertilizers. Glassy fertilizers are fertilizers with controlled dissolution, they do not pollute groundwater or surface water, the pH of the soil does not change with their use, by changing the composition they can adapt to the requirements of each crop individually, etc. The paper presents three phosphate glassy fertilizers of different chemical composition, obtained at the Center for Inorganic Technologies, ITNMS. The method of obtaining of glassy fertilizers, their dissolution rates in a medium that simulates soil conditions, the changes in pH values of solutions for different dissolution times and the effect of temperature on dissolution rates are shown. Also, the results of the influence of glass fertilizers on plant cultures in real conditions are presented.

Fosfatna stakla imaju jedinstveno svojstvo da se mogu potpuno rastvoriti u vodenim rastvorima, a brzina rastvaranja može da se kontroliše. Proces rastvaranja stakla počinje razmenom katjona sa površine stakla sa protonima iz rastvora (H+ ili H3O+) i hidratacijom staklene mreže. Početna brzina rastvaranja je osnovna karakteristika rastvaranja stakla. Analiza početnih brzina rastvaranja fosfatnog stakla, koje je dobijeno topljenjem, pokazuje da su brzine značajno veće u kiseloj sredini u odnosu na brzine rastvaranja u neutralnoj. Granulacija uzorka ima veći uticaj na početne brzine u neutralnoj sredini. Granulacija uzorka ne utiče na vrednost energije aktivacija početnih brzina rastvaranja u obe sredine. U neutralnoj sredini temperatura manje utiče na hidrolizu, a više na difuziju katjona, dok je u kiseloj sredini suprotno.

Global trends are moving towards a circular economy to replace the deeply grounded one linear economics and waste management. Circular economy implies and the protection of human rights through sustainable development, global security natural resources, combating climate change, energy security, insurance sufficient amounts of food, reducing inequalities, preservation of health and a cleaner environment and the rights of future generations to resources, etc. The policy of procurement of raw materials in the circular economy is focused on the use of secondary raw materials. A big challenge for modern production is to use different types of waste to obtain new products without the use of raw materials. This kind of production requires new knowledge, adaptation of existing technologies or new technologies, new jobs, etc. Large amounts of vegetative residues are produced annually by agriculture. Agricultural waste is very often incinerated or disposed of on land and is still not used. Most of the agricultural waste ashes consist of silicon dioxide along with other oxides which may vary according to region and atmosphere of the local conditions. This paper gives an overview of the possibilities of using agricultural waste for obtaining glass and glass ceramics. Previous research has shown that various types of glass and glass-ceramics can be successfully obtained from agricultural waste, which can be used in construction, medicine, various composites, etc.

The purpose of this study is to investigate the influence of La2O3 addition on the crystallization characteristics of polyphosphate glasses. Differential scanning calorimetry (DSC), and X-ray diffraction (XRD) methods were used to investigate the crystallization behavior of glasses. The addition of La2O3 (1-5%), at the expense of phosphate mole fraction in polyphosphate glass, raises the characteristic temperature of glasses, and resistance to crystallization. The glasses show complex crystallization leading to the formation of several crystalline phases

The increasing production of coal fly ash waste from thermal power plants has compounded environmental and economical problems worldwide. In this research coal fly ash was mixed with glass cullet and CaCO3 and melted at T= 1500 °C. The glass was milled, pressed and sintered at T= 900 °C to obtain glass- ceramic. Obtained glass- ceramic was well sintered with low crystallinity. This material, produced from secondary raw materials, could find potential application in building industry as substitute for commercial wall and floor tiles.

The crystal growth rate of lithium germanium-phosphate glass was studied. The glasses have been homogenized using the previously established temperature-time conditions, which make it possible to remove a volatile substances from the glass melt. The AAS was used to determine the chemical content of obtained glass, the differential thermal analysis (DTA), and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth, respectively. It has been found that the experimental determined crystal growth rate has a tendency toward of exponentially increase with an increase the temperature.

Potassium germanate glass with the molar ratio 30K2O·34Nb2O·36GeO2 have been synthesized by the standard melt-quenching method. The crystallization behavior under the non-isothermal crystallization conditions was investigated by the DTA and XRD methods. The results showed that this glass exposed a complex primary crystallization.

The nucleation process of lithium germanium-phosphate glass was studied to determine the temperature range of nucleation and the temperature of the maximum nucleation rate. The differential thermal analysis (DTA), and scanning electron microscope (SEM) were used to reveal the nonisothermal and isothermal process of nucleation, respectively. The crystallization process occurred at a high homogeneous nucleation rate and the spherulitic crystal growth morphology. Nanostructured samples were obtained.

The crystal growth rate of lithium germanium-phosphate glass was studied. The glasses have been homogenized using the previously established temperature-time conditions, which make it possible to remove a volatile substances from the glass melt. The AAS was used to determine the chemical content of obtained glass, the differential thermal analysis (DTA), and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth, respectively. It has been found that the experimental determined crystal growth rate has a tendency toward of exponentially increase with an increase the temperature.