Structure Of Foam Glass Research Articles

Fabrication of granular foam glass aggregates from soda lime silicate glass waste

Granular foam glass aggregates were fabricated from a soda lime silicate glass waste which utilized crude glycerol as a foaming agent and sodium silicate as a binder. The granulation and the foaming process were carried out by a granulator and an electric rotary furnace. The study investigated at first the foaming behavior of different foam glass formulations at various sintering temperatures. Three compositions were formulated which utilized glass powder at 85 wt%, 90 wt%, and 95 wt%, respectively. Sintering was carried out at temperatures from 800℃ to 1200℃ to evaluate for the foaming and melting characteristics. Foam glass with 90% glass powder showed overall uniform pore size distribution and small pores at 800℃ to 900℃ while heating above 1000℃ resulted in sample distortion caused by glass melting and the collapse of foam glass structure. Foam glass composition with 90% glass powder was selected for the fabrication of foam glass granules at the sintering temperatures of 850℃ and 900℃ in rotary furnace. The best result was obtained at 850℃ where the granules did not melt and stick together whereas at 900℃ glass melting on the surface of the foam glass granules occurred significantly.

Foam Glass Fabrication from End-of-Life Blended LCD Screen, Photovoltaic Glass Cullet and Flat Glass

End-of-life LCD screens from various waste steam have been used to formulate foam glass, aiming for use as light weight, high compressive strength, and insulation purposes. Via conventional ball milling, the foam glass powder was mixed with a binder and fabricated through compaction under 5-10 MPa using stainless steel press moulds to give green samples in cubic and plate shapes. Firing the samples at 1000 – 1050 °C for 0.5-4 hours allowed the construction of foam glass structure, giving low densities of 0.15-0.23 g/cm3. Additions of cordierite, calcium carbonate, graphite and borax determined the phases and composition of the final recycling products. Cristobalite appeared as the main phase along with anorthite were found to give high compressive strength of 1.10-4.22 MPa to the foam glass. The foam glass possessed thermal conductivity in a range of 0.1004-0.1183 W/m K, which can be used for insulation purposes. Different foam glass formulation and geometries required different firing temperature and time to acquire suitable foam glass structure for specific purposes of compressive and thermal insulation properties.

Dynamics of foam glass structure formation using glass waste and liquid foaming mixture

Foam glass, a sustainable insulation material, enhances building energy efficiency and glass waste recycling. Liquid foaming agents allow achieving uniform pore distribution and reducing production energy costs. This study explored liquid “waterglass-glycerol” mixtures in foam glass synthesis, studying foaming dynamics from room temperature and 600 °C. It reveals waterglass inhibits glycerol evaporation, while glycerol suppresses waterglass foaming. The interaction between the foaming mixture and glass powder was examined. It was found that glycerol decomposition occurs regardless of the atmosphere, but it can be intensified in oxygen. he foaming process comprises pore nuclei formation (640–770 °C), pore growth (700–840 °C), and pore coalescence (840–900 °C). A comprehensive model for “glass powder-waterglass-glycerol” foaming was developed, describing processes in liquid mixture (water evaporation, structural changes in waterglass, glycerol liquid-to-gas transition and decomposition) and thermal changes in glass (sintering, melting, foaming, and foam collapse). Insights for industrial foam glass optimization were provided, emphasizing glycerol and waterglass by-product utilization and glycerol content reduction to enhance sustainability and efficiency.

Influence of Liquid Porophore Distribution on the Formation of the Porous Structure of Foam Glass

Influence of Liquid Porophore Distribution on the Formation of the Porous Structure of Foam Glass

The Effect of Technological Additives on the Structure of Foam Glass

The Effect of Technological Additives on the Structure of Foam Glass

The influence of the annealing mode on stress elimination in a foam glass structure

The purpose of this work was to establish the influence of features of the annealing mode on the value of residual stresses in the structure of porous inorganic materials using foam glass as an example. A single-stage uniform cooling mode at three different speeds was considered. The study was performed using a mathematical model. The algorithm for analyzing the stress?strain state of the foam glass sample consisted in solving a system of equations by the finite element method. The calculation results are presented in graphic form. The graphics show the changes in stress in the foam glass upon cooling at speeds of 100, 10 and 1?C min-1. The temperature difference and the viscosity values of the foam glass subsurface and central layers in dependency on different temperatures of the cooling onset are presented. It was concluded that it is necessary to carry out the annealing mode of foam glass in three stages: initial, glass transition step and stabilization step, meaning different cooling rates have to be applied in different stages.

Computer Modeling of the Process of Synthesis of Porous Glass-Composite Materials

The operational properties of thermal insulation materials directly depend on their structure. The processes of pore formation occur inside the material after high-temperature treatment, which makes their studying more expensive and complicated. On the basis of experimental data, a computer simulation program for the process of pore formation has been developed, which makes it possible to simulate the processes of changing the structure of foam glass during heat treatment without repeated laboratory experiments.

Fabrication of Lightweight Foam Glasses for Thermal Insulation Applications

Abstract Foam glasses were fabricated using glass powder obtained from consumable waste glass bottles as the main raw material. Sodium silicate was used as the binder in all mixtures. Yellow glycerol obtained from biodiesel production (contained ∼80% glycerol, 10% water, 10% methanol, fatty acids and other materials) and sodium carbonate were used as foaming agents. Factors which influenced the foaming behavior included type of foaming agent, amount of foaming agent and heating rate. These factors affected pore formation within the foam glass structure which in turn affected physical, mechanical and thermal properties of the synthesized foam glass. In this study foam glass with the most outstanding properties had thermal conductivity value of 0.260 W/mK, which was fabricated with a composition of 92 wt.% glass powder, 3.5 wt.% sodium silicate, 3.5 wt.% glycerol and 1.0 wt.% sodium carbonate. The mixture was heated at 850°C using a heating rate of 10°C /min and 30 min holding time at maximum temperature. This composition showed the average bulk density value of 0.67 g/cm3 and the highest average compressive strength value of 166 kg/cm2. Foam glasses using waste glass bottles in this study may provide a promising way to fabricate lightweight construction materials with excellent thermal insulating property.

STUDY AND SIMULATION OF HEAT TRANSFER PROCESSES DURING FOAM GLASS HIGH TEMPERATURE PROCESSING

The paper presents basic aspects of simulation of pores formation and growth in the foam glass structure process during raw material mixture high temperature processing. The key mathematical approaches to heat transfer processes simulation and the dynamics of the pores radius growth in the raw material mixture structure are presented. The key assumptions and restrictions allowing representing the most adequate research outcomes at this stage of the subject development are outlined.

KINETICS OF STRUCTURAL TRANSFORMATIONS AT PORES FORMATION DURING HIGH-TEMPERATURE TREATMENT OF FOAM GLASS

The work shows the key points used in the simulation of pores formation and growth in the foam glass structure. Pore is represented as a separate radius growth center with the outer boundary of a spherical shape and with a specified value of the initial radius surrounded by a finite volume of molten glass that is a part of foam glass charge stock. Solution of three-dimensional problem is reduced to one-dimensional setting in spherical coordinates. The presented model takes into consideration kinetics of pores radius growth, taking into account the influence of glass viscosity and surface tension, as well as the effect of moving (stretching) glass cladding when pores radius increases.

Analysis of Influence of Foaming Mixture Components on Structure and Properties of Foam Glass

It is recommended to use high-quality thermal insulation materials to increase the energy efficiency of buildings. One of the best thermal insulation materials is foam glass - durable, porous material that is resistant to almost any effect of substance. Glass foaming is a complex process depending on the foaming mode and the initial mixture composition. This paper discusses the influence of all components of the mixture – glass powder, foaming agent, enveloping material and water - on the foam glass structure. It was determined that glass powder is the basis of the future material. A foaming agent forms a gas phase in the process of thermal decomposition. This aforementioned gas foams the viscous glass mass. The unreacted residue thus changes a colour of the material. The enveloping agent slows the foaming agent decomposition preventing its premature burning out and, in addition, helps to accelerate the sintering of glass particles. The introduction of water reduces the viscosity of the foaming mixture making it evenly distributed and also promotes the formation of water gas that additionally foams the glass mass. The optimal composition for producing the foam glass with the density of 150 kg/m3 is defined according to the results of the research.

Physical Characteristics of Foam Glass Modified with Zirconium Dioxide

The paper examines physical properties of foam glass material modified with 0.3 mass% nano-sized zirconium dioxide. It presents experimental data on the foam glass structure on micro- and meso-levels. The authors make a conclusion about influence and mutual subordination of structural levels in the glass materials. The presence of nanocrystallites (25 nm) located in the amorphous matrix in an ordered fashion and the pore packing that is correct from the symmetry standpoint provide for the enhanced strength of the porous structure. Findings show that the introduction of nano-sized zirconium dioxide leads to the emergence of a hierarchical and mutually subordinate system. The paper concludes that small additions of zirconium oxide have a positive effect on physical and mechanical properties of foam glass material.

Effect of Auxiliaries on Pore Structure of Foam Glass

In this paper, foam glass as thermal insulation material was prepared from alkali-free glass powder, and silicon carbide was used as foaming agent in the process. The effect of silicon carbide and sodium carbonate was investigated. Thermal performance of the batch was investigated by using the TG/DSC simultaneous thermal analyzer. The morphology of the glass foams was evaluated by the scanning electron microscopy. The phase of the sample was studied through X-ray diffraction, and chemical composition of the samples was estimated by using X-ray fluorescence spectrum. The results show that, the pore diameter of sample increases gradually at first and then stabilizes with the increasement of silicon carbide. Sodium carbonate not only improves the foaming ability by reducing the glass viscosity but also influences the crystallization of the sample. The bulk density and compressive strength are decreasing while the content of sodium carbonate increasing.

Fractal Analysis in Assessing the Porous Structure of Foam Glass

It is shown that fractal analysis can be used to describe the structure of foam glass. It is proposed that the fractal dimension be used for quantitative assessment of foam-glass structure with fixed action of different technological factors. The interrelation of between the fractal dimension and the main technical characteristics of foam glass is determined.

Effect of Carbon as Foaming Agent on Pore Structure of Foam Glass

Insulation effect and mechanical performance of foam glass depend, to a large extent, on foam structure. Hence understanding foam formation is not only a problem of significant fundamental interest but also of tremendous practical impact. In this paper, foam growth was modeled comparing to grain growth theory in sintering. TG-DTG analysis of carbon black indicated that pre-oxidation took place prior to foaming temperature. Furthermore effects of heating rate and particle size of carbon black on foam structure have been taken into account. Several borosilicate foam glasses were fabricated by powder sintering process at different heating rates using carbon black of different particle sizes as foaming agent, respectively. It was found that increasing the heating rate tended to decrease the pre-oxidation of carbon black resulting in inhomogeneous foam distribution. Foam structure of sample heated at a rate of 8°C/min using carbon black with particle size of 0.15mm was optimal.

Study of the structure of foam glass with different characteristics

The results of a study of the micro-and macroscopic structure of foam glass with different characteristics are reported.

Characterisation of porous glasses prepared from Cathode Ray Tube (CRT)

Display tubes such as those used in TV receivers and computer monitors have an evacuated glass envelope, which consists mainly of a screen (front component) and a funnel (back component hidden inside the TV set or monitor). These two components have different compositions: the screen is composed of lead-free glass with strontium and barium oxides, whereas the funnel is composed of glass with lead oxides. In order to comply with future government measures, a method is required for the recycling or re-utilisation of CRT (Cathode Ray Tube) glasses in end-of-life electronic goods. One open-loop recycling method is to create foam glasses from CRTs using a reducing agent. The results for the chemical compositions of these glasses and their physical properties showed that foam glasses can be prepared from glasses from various CRT glassmakers. In this paper, we use several methods to determine the structures of these foam glasses. We use helium pycnometry, Hg porosimetry, specific surface area measurements and scanning electron microscopy as direct methods for determining foam glass structure. These methods provide information about the morphologies and reactivities of these porous materials. Densities, porosities and pore size distributions were measured, which enable us to suggest some potential applications for the fabricated foam glasses.