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.

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 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 Evaluation of Physical Properties of a Metakaolin-Based Alkali-Activated Binder Containing Waste Foam Glass

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5458
Author(s):  
Petra Mácová ◽  
Konstantinos Sotiriadis ◽  
Zuzana Slížková ◽  
Petr Šašek ◽  
Michal Řehoř ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Physical Properties ◽  
Foam Glass ◽  
Glass Production ◽  
Alkali Activation ◽  
Activation Process ◽  
X Ray ◽  
Thermal Insulating ◽  
The Matrix ◽  
Alkali Activated

Foam glass production process redounds to large quantities of waste that, if not recycled, are stockpiled in the environment. In this work, increasing amounts of waste foam glass were used to produce metakaolin-based alkali-activated composites. Phase composition and morphology were investigated by means of X-ray powder diffraction, Fourier-transform infrared spectroscopy and scanning electron microscopy. Subsequently, the physical properties of the materials (density, porosity, thermal conductivity and mechanical strength) were determined. The analysis showed that waste foam glass functioned as an aggregate, introducing irregular voids in the matrix. The obtained composites were largely porous (>45%), with a thermal conductivity coefficient similar to that of timber (<0.2 W/m∙K). Optimum compressive strength was achieved for 10% incorporation of the waste by weight in the binder. The resulting mechanical properties suggest the suitability of the produced materials for use in thermal insulating applications where high load-bearing capacities are not required. Mechanical or chemical treatment of the waste is recommended for further exploitation of its potential in participating in the alkali activation process.

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 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 Foam Glass Gravel Experimentally Made in a 10 kW-Microwave Oven

2021 ◽  
Vol 2 (2) ◽  
pp. 37-46
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Felicia Cosmulescu
Keyword(s):  
Water Glass ◽  
Foam Glass ◽  
Specific Energy Consumption ◽  
Microwave Oven ◽  
Small Extent ◽  
Glass Waste ◽  
Foaming Agent ◽  
Internal Volume ◽  
Made In

Abstract                                                         The experimental manufacture of foam glass gravel from glass waste has been quantitatively extended by increasing the power of the microwave oven from 0.8 to10 kW, the authors' interest being focused on the quality of the foamed product. The work equipment was rather improvised, the existing used oven not being adequate except to small extent for the requirements of the experiment, but it allowed obtaining a product similar to those industrially manufactured by conventional techniques. Using a recipe previously tested on the 0.8 kW-microwave oven composed of 1 wt.% glycerol as a liquid foaming agent together with 8 wt.% water glass as an enveloping agent and 8 wt.% water as a binder, the main features of the foam glass gravel lumps were: bulk density of 0.22 g/cm3, porosity of 88.9%, thermal conductivity of 0.057 W/m·K, compressive strength of 5.9 MPa and pore size between 0.10-0.30 mm. The specific energy consumption was negatively influenced by the excessive internal volume of the oven, but even under these conditions its value was relatively low (between 1.53-1.69 kWh/kg).

scholarly journals USING SECONDARY RAW MATERIALS IN LIGHTWEIGHT OPEN-STRUCTURE CONCRETE WITH GOOD UTILITY PROPERTIES

2019 ◽  
Vol 22 ◽  
pp. 94-98
Author(s):  
Martin Sedlmajer ◽  
Jiří Zach ◽  
Jan Bubeník
Keyword(s):  
Mechanical Properties ◽  
Lightweight Concrete ◽  
Raw Materials ◽  
Foam Glass ◽  
Acoustic Properties ◽  
Recycled Pet ◽  
Open Structure ◽  
Recycled Glass ◽  
Thermal Insulating ◽  
Glass Aggregate

The paper presents the results of research in lightweight concrete with open structure made using a lightweight porous foam-glass aggregate produced from recycled glass powder. The goal was to develop lightweight concrete. In order to achieve the best possible properties while reducing binder content, the concrete was reinforced with by-product fibres, which helped reduce the weight of the concrete while delivering satisfactory mechanical properties. In the paper are proposed lightweight concrete with open structure made using foam-glass aggregate. Mechanical, thermal-insulating and acoustic properties were determined on lightweight concrete. Designed concrete is only made of crushed lightweight foam-glass aggregate with a combination of Portland cement with the option of adding recycled PET fibres. The new concretes possess a very good ratio of thermal insulation to mechanical properties as well as good sound absorption.

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

2020 ◽  
Vol 26 (1) ◽  
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

<p>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/cm<sup>3</sup>, 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.</p>

CMW 100

Alloy Digest ◽  
2000 ◽  
Vol 49 (10) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Copper Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Age Hardening ◽  
High Tensile Strength ◽  
Electrical Components ◽  
Flash Welding ◽  
Hardening Heat Treatment

Abstract CMW 100 is a copper alloy that combines high tensile strength with high electrical and thermal conductivity. It responds to age-hardening heat treatment. It is used for flash welding dies, springs, electrical components, high-strength backing material for brazed assemblies, and wire guides. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CU-29. Producer or source: CMW Inc. Originally published as Mallory 100, August 1955, revised October 2000.

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