scholarly journals Glass Foam Made with Silicon Nitride and Manganese Oxide by Microwave Irradiation

2021 ◽  
Vol 2 (2) ◽  
pp. 1-9
Author(s):  
Marius Florin Dragoescu ◽  
Lucian Paunescu ◽  
Sorin Mircea Axinte
Keyword(s):  
Flat Glass ◽  
Morphological Characteristics ◽  
Raw Material ◽  
Conventional Heating ◽  
Insulation Material ◽  
Glass Waste ◽  
High Mechanical Strength ◽  
Foaming Agent ◽  
Optimal Sample ◽  
Glass Foam

A high mechanical strength (6.1 MPa) glass foam was produced by sintering/foaming at 830 ºC in an experimental 0.8 kW-microwave oven. The basic raw material was a colorless flat glass waste and the foaming agent was Si3N4 powder (2 wt.%). As an oxygen supplying agent, a MnO2 powder (3.1 wt.%) was used. The main physical, mechanical, thermal and morphological characteristics of the optimal sample were: apparent density of 0.47 g/cm3, porosity of 77.6%, thermal conductivity of 0.105 W/m·K, compressive strength of 6.1 MPa and pore size between 0.15-0.40 mm. The optimal glass foam sample has the required characteristics of a thermal insulation material usable under mechanical stress conditions in civil engineering. The originality of the paper is the application of the unconventional microwave heating technique, faster and more economical, unlike the other papers in the same area published in the literature, followers of the traditional conventional heating technique.

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 NONCONVENTIONAL TECHNIQUE FOR PRODUCING HIGH MECHANICAL STRENGTH GLASS FOAM FROM GLASS WASTE

2019 ◽  
Vol 25 (2) ◽  
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE ◽  
ANA CASANDRA SEBE
Keyword(s):  
Thermal Conductivity ◽  
Energy Source ◽  
Mechanical Strength ◽  
Electromagnetic Waves ◽  
Building Materials ◽  
Glass Waste ◽  
High Mechanical Strength ◽  
Foaming Agent ◽  
Heating Efficiency ◽  
Glass Foam

In the work experimental results on the manufacture of glass foam with high mechanical strength from glass waste are presented. By replacing the usual conventional energy source with a nonconventional energy (electromagnetic waves) the heating efficiency allows a fast and economical manufacturing process. Calcium carbonate as a foaming agent and an addition of sodium silicate (aqueous solution) as a binder were used. By their physico-mechanical and morphological features (0.40-0.66 g/ cm<sup>3 </sup>the apparent density, 0.054-0113 W/ m·K the thermal conductivity, 2.2-6.3 MPa the compressive strength, below 1.2 % the water absorption and under 2 mm the pore size), the foams are appropriate for their use as replacer of existing similar building materials on the market.

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>

NONCONVENTIONAL TECHNIQUE FOR PRODUCING HIGH MECHANICAL STRENGTH GLASS FOAM FROM GLASS WASTE

2019 ◽  
Vol 25 (2) ◽  
pp. 48-55
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE ◽  
ANA CASANDRA SEBE
Keyword(s):  
Thermal Conductivity ◽  
Energy Source ◽  
Mechanical Strength ◽  
Electromagnetic Waves ◽  
Building Materials ◽  
Glass Waste ◽  
High Mechanical Strength ◽  
Foaming Agent ◽  
Heating Efficiency ◽  
Glass Foam

In the work experimental results on the manufacture of glass foam with high mechanical strength from glass waste are presented. By replacing the usual conventional energy source with a nonconventional energy (electromagnetic waves) the heating efficiency allows a fast and economical manufacturing process. Calcium carbonate as a foaming agent and an addition of sodium silicate (aqueous solution) as a binder were used. By their physico-mechanical and morphological features (0.40-0.66 g/ cm3 the apparent density, 0.054-0113 W/ m·K the thermal conductivity, 2.2-6.3 MPa the compressive strength, below 1.2 % the water absorption and under 2 mm the pore size), the foams are appropriate for their use as replacer of existing similar building materials on the market.

scholarly journals Synthesis and characterization of innovative insulation materials

2018 ◽  
Vol 149 ◽  
pp. 01078
Author(s):  
Aggeliki Skaropoulou ◽  
Afroditi Ntziouni ◽  
Dimitris Kioupis ◽  
Sotiris Tsivilis ◽  
Glikeria Kakali
Keyword(s):  
Raw Materials ◽  
Raw Material ◽  
Synthesis And Characterization ◽  
Insulation Material ◽  
Foaming Agent ◽  
Insulation Materials ◽  
Major Disadvantage ◽  
Reinforcing Agent ◽  
By Products

Insulation elements are distinguished in inorganic fibrous and organic foamed materials. Foamed insulation materials are of great acceptance and use, but their major disadvantage is their flammability. In case of fire, they tend to transmit the flame producing toxic gases. In this paper, the synthesis and characterization of innovative inorganic insulation materials with properties competitive to commercial is presented. Their synthesis involves the mixing of inorganic raw material and water with reinforcing agent or/and foaming agent leading to the formation of a gel. Depending on raw materials nature, the insulation material is produced by freeze drying or ambient drying techniques of the gel. The raw material used are chemically benign and abundantly available materials, or industrial by-products and the final products are non-toxic and, in some cases, non-flammable. Their density and thermal conductivity was measured and found 0.02-0.06 g/cm3 and 0.03-0.04 W/mK, respectively.

THERMAL INSULATING MATERIAL WITH HIGH MECHANICAL STRENGTH MADE FROM CLAY BRICK WASTE AND COAL ASH USING THE MICROWAVE ENERGY

2020 ◽  
Vol 26 (2) ◽  
pp. 28-34
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE
Keyword(s):  
Mechanical Strength ◽  
Coal Ash ◽  
Microwave Energy ◽  
Raw Material ◽  
Clay Brick ◽  
High Mechanical Strength ◽  
Foaming Agent ◽  
Insulating Material ◽  
Thermal Insulating ◽  
Foaming Process

The paper presents the results of experimental research for manufacture a high mechanical strength thermal insulating material using the microwave energy. Clay brick waste (75 - 83 mass %) and coal ash (15 - 23 mass %) as raw material and silicon carbide (2%) as a foaming agent have been used as a powder mixture. The porous product obtained by a sintering/ foaming process at 1115 - 1145 ºC had relatively low density and thermal conductivity (0.50 - 0.68 g/cm3 and 0.078 - 0.095 W/mK, respectively) and high compressive strength (up to 7.5 MPa). This remarkable combination of some physical and mechanical characteristics of the insulating material allows its use in applications involving mechanical stress resistance.

DENSE GLASS FOAM PRODUCED IN MICROWAVE FIELD

2018 ◽  
Vol 24 (1) ◽  
pp. 30-35
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE ◽  
BOGDAN VALENTIN PAUNESCU
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Building Materials ◽  
Microwave Field ◽  
Microwave Energy ◽  
Glass Waste ◽  
Foaming Agent ◽  
Mechanical Feature ◽  
Glass Foam ◽  
Fluxing Agent

Experimental results obtained in the process of manufacturing dense glass foam using the microwave energy are presented in the work. The glass foam is produced from bottle glass waste, calcium carbonate as foaming agent and borax as fluxing agent. The high compressive strength (2.5 - 6.2 MPa) is the main mechanical feature of this product, which together with other physical and morphological features (apparent density 0.60 – 0.90 g/cm3, porosity 59.1 – 72.7%, thermal conductivity 0.081 – 0.105 W m K, water absorption 0.5 – 1.0%, pore size 0.5 – 3 mm), are appropriate for using as a substitute for similar building materials existing on the market.

scholarly journals New Manufacturing Method of Glass Foam by Cold Expansion of Glass Waste

2021 ◽  
Vol 2 (3) ◽  
pp. 1-9
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Bogdan Valentin Paunescu
Keyword(s):  
Thermal Conductivity ◽  
Aqueous Solution ◽  
Compressive Strength ◽  
High Temperature ◽  
Insulation Material ◽  
Glass Waste ◽  
Foaming Agents ◽  
Manufacturing Method ◽  
Aluminium Powder ◽  
Glass Foam

Abstract                                                         An innovation cold manufacturing method of glass foams is presented in the paper. Traditional foaming agents used in conventional expansion processes of glass waste at high temperature were substituted with aluminium powder in aqueous solution of calcium hydroxide, which releases hydrogen forming gas bubbles in the viscous sludge and then, by solidification, a porous structure typical for the glass foam. The manufactured foam is adequate for using as a thermal insulation material for inner wall of buildings, having the apparent density of 0.31 g·cm-3, the thermal conductivity of 0.070 W/m·K and the compressive strength of 1.32 MPa. The process originality is the use of recycled aluminum waste, melted by an own microwave heating technique and sprayed with nitrogen jets. The process effectiveness is remarkable in economical and energy terms.

scholarly journals Ultra-light Colorless and Green Glass Foam Produced by Microwave Radiation

2021 ◽  
Vol 2 (1) ◽  
pp. 1-12
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Felicia Cosmulescu ◽  
Marius Florin Dragoescu ◽  
Bogdan Valentin Paunescu
Keyword(s):  
High Performance ◽  
Microwave Field ◽  
Specific Energy Consumption ◽  
High Energy ◽  
Glass Waste ◽  
Foaming Agent ◽  
Very High Energy ◽  
Green Glass ◽  
Glass Foam ◽  
Very High

Abstract                                                         According to the research objective that was the basis of the paper, an ultra-light glass foam with an apparent density of 0.14 g/cm3 was experimentally made from 98.9% post-consumer glass bottle and 1% CaCO3 as a foaming agent by sintering/foaming at 823 ºC in microwave field with a very low specific energy consumption (0.70 kWh/kg). A very advanced mechanical processing of glass waste (below 32 μm) and a very fine granulation (below 6.3 μm) of CaCO3 were the solutions adopted to obtain this high-performance product. The originality of the work is the use of the unconventional technique of predominantly direct microwave heating with a very high energy efficiency, applied by authors in recent years and presented in several previous papers.

scholarly journals Manufacture of Cellular Glass Using Oak Leaves as a Foaming Vegetable Agent

2020 ◽  
Vol 1 (4) ◽  
pp. 18-27
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Marius Florin Dragoescu ◽  
Felicia Cosmulescu
Keyword(s):  
Specific Energy Consumption ◽  
Building Construction ◽  
Raw Material ◽  
Conventional Heating ◽  
Insulating Materials ◽  
Foaming Agent ◽  
Thermal Insulating ◽  
Cellular Glass ◽  
Oak Leaves ◽  
Material Powder

Abstract                                                         The manufacture experimentation of a cellular glass exclusively from mineral waste and natural residues using the unconventional technique of microwave irradiation was the objective of the research whose results are presented in the paper. The originality of the paper results from the use of oak leaves as a vegetable foaming agent as well as the use of microwave energy in heating processes of the raw material powder mixture for manufacturing thermal insulating materials for the building construction. Worldwide, these processes use only conventional heating techniques. The experimental results led to the conclusion that both the use of waste and residues, as well as the unconventional heating technique allow to obtain porous materials with structural homogeneity having apparent densities and thermal conductivities that can decrease up to 0.34 g/cm3, and 0.071 W/m·K respectively. The compressive strength corresponding to the materials with the lowest values of density and thermal conductivity has an acceptable value (1.2 MPa) for the field of application. The specific energy consumption is around 1 kWh/kg, being approximately at the same level with the values of industrial consumptions achieved by conventional techniques.

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