FOAM GLASS GRAVEL MADE OF RECYCLED GLASS WASTE AND SILICON CARBIDE BY MICROWAVE HEATING

2020 ◽  
Vol 26 (3) ◽  
pp. 173-180
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE
Keyword(s):  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Mechanical Characteristics ◽  
Foam Glass ◽  
Specific Energy Consumption ◽  
Conventional Heating ◽  
Industrial Processes ◽  
Glass Waste ◽  
Recycled Glass ◽  
Physical And Mechanical Characteristics

The paper presents recent achievements in the microwave use for manufacturing foam glass gravel from recycled glass waste and silicon carbide. The aim was to obtain a product with physical and mechanical characteristics almost similar to those of industrially manufactured materials by conventional heating techniques, but with a higher energy efficiency. A foam glass with the thermal conductivity of 0.075 W/m·K and the compressive strength of 7.5 MPa was experimentally obtained. The specific energy consumption was of 1.0 kWh/kg comparable with the industrial processes and it could reach values up to 25% lower by using a high power industrial microwave equipment.

scholarly journals Microwave Heat Treatment to Manufacture Foam Glass Gravel

2021 ◽  
Vol 2 (1) ◽  
pp. 20-28
Author(s):  
Lucian Paunescu
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Foam Glass ◽  
Specific Energy Consumption ◽  
Sodium Borate ◽  
Water Addition ◽  
Glass Waste ◽  
Recycled Glass ◽  
Thermal Insulating ◽  
Microwave Heat

Abstract                                                         The paper aimed at the experimental manufacture of a foam glass gravel type by sintering at over 900 ºC a powder mixture composed of recycled glass waste (92%), sodium borate (6%), kaolin (0.3%), silicon carbide (1.7%) and water addition (12%). The originality of the work was the application of the unconventional technique of microwave heating through a predominantly direct heating procedure. The product foamed at 908 ºC had a very fine porous structure (pore size between 0.05-0.20 mm) and a compressive strength above the usual level of foam glass gravels (7.8 MPa). The apparent density of 0.28 g/cm3 corresponding to a bulk density of 0.20 g/cm3 and the thermal conductivity of 0.075 W/m·K ensures the thermal insulating character of the material required for use in the specific field of applications of foam glass gravel. The manufacturing process had an excellent energy efficiency, the specific energy consumption decreasing up to 0.70 kWh/kg.

scholarly journals Development of lightweight structural concrete with the use of aggregates based on foam glass

2021 ◽  
Vol 1205 (1) ◽  
pp. 012014
Author(s):  
J Zach ◽  
J Bubeník ◽  
M Sedlmajer
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Foam Glass ◽  
Research Work ◽  
Acoustic Properties ◽  
Added Value ◽  
Glass Waste ◽  
Recycled Glass ◽  
Foamed Glass

Abstract Lightweight concretes are increasingly being used in the construction industry, either for the overall lightweighting of the structure itself, reducing material consumption for construction and thus CO2 emissions, or for specific reasons such as improving the thermal insulation properties of the structure or acoustic properties. Today, lightweight concretes with lightweight expanded aggregates (expanded clay, agloporite) are most commonly used. This paper deals with the production of lightweight concretes lightweighted with foamed glass-based aggregates. Foamed glass is a lightweight material characterised by a very good ratio of thermal insulation and mechanical properties. Foamed glass is made of approximately 90% recycled glass waste (mostly mixed), which cannot be used in any other way, as well as water glass and glycerine. When concrete is lightened with foamed glass, these concretes achieve unique properties while conserving primary aggregate resources, avoiding landfilling of glass waste and efficiently using the waste material to produce lightweight concrete with higher added value. The paper discusses the possibilities of developing lightweight structural concretes using glass foam-based aggregates to achieve higher strength classes while reducing the weight and thermal conductivity of the concrete. As part of the research work, new types of lightweight concrete with a bulk density in the range of 1750–1930 kg/m3 and a thermal conductivity from 0.699 to 0.950 W/(m·K) were developed.

scholarly journals Physico-Mechanical Properties and Microstructure of Polymer Concrete with Recycled Glass Aggregate

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1213 ◽  
Author(s):  
Bartosz Zegardło ◽  
Maciej Szeląg ◽  
Paweł Ogrodnik ◽  
Antoni Bombik
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Mechanical Characteristics ◽  
Polymer Concrete ◽  
Glass Waste ◽  
Recycled Glass ◽  
Glass Aggregate ◽  
Basic Features ◽  
Scanning Electron ◽  
Physical And Mechanical Characteristics

The paper presents an analysis of the possibility of using glass waste from worn out lighting materials as an aggregate for a polymer concrete. Glass waste was obtained from the company utilizing glass lighting elements, which was then subjected to crushing. The aggregate obtained was subjected to the tests of basic features, which were compared with aggregates that are traditionally applied to concretes. The next stage of the research program was the production of a polymer concrete that contained glass aggregate. Several types of mixtures were prepared in which glass waste was combined in various proportions with traditional sand–gravel aggregate. As a part of the research, the basic physical and mechanical characteristics of polymer concretes were determined. The microstructure of composites was also analyzed using a scanning electron microscope. The results of the research have shown that the aggregate obtained from glass waste can be successfully used for the production of a polymer concrete. The most beneficial physico-mechanical properties were obtained for a composite in which glass waste was used as a 50% substitute for traditional aggregate.

Refractory Core-Shell Powders for Additive Industries

2017 ◽  
Vol 265 ◽  
pp. 529-534 ◽  
Author(s):  
Sergey P. Bogdanov ◽  
A.P. Garshin
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Composite Materials ◽  
Boron Nitride ◽  
Tungsten Carbide ◽  
Mechanical Characteristics ◽  
Core Shell ◽  
Refractory Materials ◽  
Iodide Transport ◽  
Physical And Mechanical Characteristics

The finished products obtained when the surfaces of powders of refractory materials (diamond, boron nitride, silicon carbide, tungsten carbide, tungsten) were coated with thin films by the method of iodide transport are presented. The developed method enables to obtain powder composite materials of core-shell type that have surface thickness varying in the range from 1 nm to several micrometers. From the powders modified by the films of metals and thier compounds composite materials were developed, their physical and mechanical characteristics were studied. The characteristics turned out to be substantially higher in comparison to materials sintered from the same powders but without coating. The probable fields of use of the composites in question were determined.

scholarly journals Unconventional Technique for Producing Borosilicate Glass Foam

2021 ◽  
Vol 1 (6) ◽  
pp. 12-22
Author(s):  
Lucian Paunescu ◽  
Marius Florin Dragoescu ◽  
Sorin Mircea Axinte ◽  
Felicia Cosmulescu
Keyword(s):  
Thermal Conductivity ◽  
Borosilicate Glass ◽  
Specific Energy Consumption ◽  
Microwave Oven ◽  
Experimental Equipment ◽  
Glass Waste ◽  
Homogeneous Microstructure ◽  
Advanced Technique ◽  
The World ◽  
Glass Foam

The study aims to test an advanced technique but insufficiently valued in the world in the process of experimental manufacture of borosilicate glass foam. It is about the unconventional technique of heating solids by using the microwave radiation converted into heat. The experimental equipment on which the tests were performed was a 0.8-kW microwave oven commonly used in the household with constructive adaptations to be operational at high temperature. The adopted manufacturing recipe was composed of borosilicate glass waste with the addition of calcium carbonate, boric acid and water in different weight proportions. The material was sintered at 829-834 ºC by predominantly direct microwave heating and the optimal foamed product had characteristics similar to those manufactured by conventional techniques (apparent density of 0.33 g/cm3, thermal conductivity of 0.070 W/m•K, compressive strength of 3.1 MPa and a homogeneous microstructure with pore size between 0.7-1.0 mm). The energy efficiency of the unconventional manufacturing process was remarkable, the specific energy consumption being only 0.92 kWh/kg.

scholarly journals FLUORO​AN​HYDRITE COMPOSITIONS PLASTICIZED BY POLYCARBOXYLATE ESTERS

2020 ◽  
Vol 11 (3) ◽  
pp. 101-105
Author(s):  
Daria A. Kalabina ◽  
Grigorij I. Yakovlev ◽  
Zdenek Dufek ◽  
Grigoriy N. Pervushin ◽  
Kirill A. Bazhenov ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Mechanical Characteristics ◽  
Water Resistance ◽  
Microstructural Analysis ◽  
High Strength ◽  
Expanded Perlite ◽  
Fluid Mixtures ◽  
Water Base ◽  
Physical And Mechanical Characteristics

The influence of a plasticizer based on polycarboxylate esters on the properties of a high-strength fluoroanhydrite composition and a lightweight composition with expanded perlite sand is investigated. It was shown that the addition of 2% polycarboxylate esters on water base to compositions has increased compressive strength and a flexural strength up to 46% and 20% respectively compare to composite without any additives. Due to the structure’s compaction of the compositions, water absorption decreased and the water resistance of the material increased. Microstructural analysis of the compositions confirmed the improvement of physical and mechanical characteristics by changing the morphology of crystallohydrate formations, increasing the contact area between new formations and modifying the structure by carbon nanotubes. The developed mixtures are supposed to be apply for self-leveling fluid mixtures for floors with reduced thermal conductivity.

scholarly journals Experimental Use of Microwaves in the High Temperature Foaming Process of Glass Waste to Manufacture Heat Insulating Material in Building Construction

2020 ◽  
Vol 1 (3) ◽  
pp. 17-26
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Marius Florin Dragoescu ◽  
Felicia Cosmulescu
Keyword(s):  
Thermal Conductivity ◽  
Energy Consumption ◽  
High Temperature ◽  
Specific Energy Consumption ◽  
Coal Ash ◽  
Building Construction ◽  
Raw Material ◽  
High Porosity ◽  
Glass Waste ◽  
Cellular Glass

Abstract                                                         The aim of the paper was the experimental manufacture of cellular glass from glass waste and coal ash as raw material and silicon carbide as a foaming agent, using the unconventional microwave heating technique. This heating technique, although known since the last century and recognized worldwide as fast and economical, is not yet industrially applied in high temperature thermal processes. The cellular glass manufacturing process requires high temperatures and the use of microwaves in this process is the originality of the work. The experiments aimed at producing thermal insulating materials with high porosity and low thermal conductivity for building construction similar in terms of quality to those manufactured industrially by conventional techniques, but with lower energy consumption. The obtained samples had adequate characteristics (apparent density 0.22-0.32 g/cm3, porosity 85.5-90.0%, thermal conductivity 0.043-0.060 W/m·K, compressive strength 1.23-1.34 MPa), and the specific energy consumption was low (0.84-0.89 kWh/kg). Theoretically, given the use of microwave equipment on an industrial scale, this consumption comparable in value to that industrially achieved by conventional techniques could decrease by up to 25%.

USE OF NATURAL DOLOMITE AS A CHEAP FOAMING AGENT FOR PRODUCING GLASS FOAMS FROM GLASS WASTE IN THE MICROWAVE FIELD

2020 ◽  
Vol 26 (1) ◽  
pp. 57-64
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE
Keyword(s):  
Thermal Conductivity ◽  
Microwave Field ◽  
Specific Energy Consumption ◽  
Morphological Characteristics ◽  
Microwave Energy ◽  
Glass Waste ◽  
Foaming Agent ◽  
Insulating Material ◽  
The World ◽  
Glass Foam

The paper presents experimental results obtained in the process of making glass foam from glass waste using a cheap foaming agent (natural dolomite). The originality of the work is the application of the microwave energy, unlike the conventional techniques commonly used in the world. The main advantage highlighted by the experiments is the very low specific energy consumption (below 1.5 kWh/kg), due to the peculiarities of the microwave heating technique. The foamed product has physical, mechanical and morphological characteristics (density between 0.30-0.32 g/cm3, thermal conductivity between 0.064-0.067 W/m·K, compressive strength in the range 2.2-2.6 MPa), which are similar to those of foams made by conventional methods and are suitable for its use as insulating material in construction.

scholarly journals Manufacture of Glass Foam by Predominantly Direct Microwave Heating of Recycled Glass Waste

2019 ◽  
Vol 7 (4) ◽  
pp. 37-45
Author(s):  
Sorin Mircea AXINTE ◽  
Lucian Paunescu ◽  
Marius Florin Dragoescu ◽  
Ana Casandra Sebe
Keyword(s):  
Microwave Heating ◽  
Foam Glass ◽  
Weight Ratio ◽  
Original Method ◽  
Microwave Energy ◽  
Waste Glass ◽  
Conventional Heating ◽  
Thin Wall ◽  
Glass Waste ◽  
Materials Used

The paper presents authors’ contribution to the improvement of the manufacturing technique of foam glass using the microwave energy. Due to the physical and mechanical characteristics, this material, obtained by the sintering process of waste glass at high temperature, constitutes a viable replacer of existing similar materials, used especially in construction. Unlike the conventional heating methods used worldwide, the company Daily Sourcing & Research SRL Bucharest tested lately microwave heating techniques in the manufacturing process of foam glass. In the paper it is presented an original method based on the feature of the powder mixture composed by waste glass (over 97 wt.%) and the foaming agent (calcium carbonate) to absorb the microwave energy and convert it to heat since the ambient temperature, using a silicon carbide and silicon nitride (80/ 20 weight ratio) crucible with thin wall (2.5 mm), which allows both a preponderantly direct heating and partially an indirect heating of the material. The main parameters of the process (specific consumption of energy, heating speed, process temperature and duration) were significant improved compared to the previous experiments.

Development of a porous catalytic converter for the dehydrogenation of cumene to α-methylstyrene

2020 ◽  
pp. 8-13
Author(s):  
V. I. Uvarov ◽  
R. D. Kapustin ◽  
A. O. Kirillov ◽  
A. S. Fedotov ◽  
M. V. Tsodikov
Keyword(s):  
Silicon Carbide ◽  
Open Porosity ◽  
Eutectic Composition ◽  
Mechanical Characteristics ◽  
Catalytic Properties ◽  
Catalytic Converter ◽  
Initial Mixture ◽  
Combustion Mode ◽  
Catalytically Active ◽  
Physical And Mechanical Characteristics

A porous catalytically active membrane based on α-Al2O3 has been synthesized. Powdered additives of the eutectic composition of magnesium oxide and silicon carbide were introduced with the initial corundum filler to synthesize the membrane frame with high open porosity and physical and mechanical characteristics. Then, pressing was carried out at a pressure of 40 to 70 MPa, followed by sintering in the process combustion mode. Additives Re2O7 and WO3 up to 4 wt. % was introduced into the initial mixture by a simple technological method to impart catalytic properties to the synthesized membrane. The scientific foundations have been developed for creating a technology for one-stage production of catalytically active ultraporous membrane converters effective for the processes of cumene dehydrogenation to α-methylstyrene.

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