scholarly journals Unconventionally Made-Cellular Glass Aggregate

2021 ◽  
Vol 2 (6) ◽  
pp. 21-31
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Felicia Cosmulescu
Keyword(s):  
Calcium Carbonate ◽  
Sodium Silicate ◽  
Electromagnetic Waves ◽  
Microwave Field ◽  
Industrial Processes ◽  
Sodium Borate ◽  
Residual Glass ◽  
Cellular Glass ◽  
Glass Aggregate ◽  
Fluxing Agent

Improving the original manufacturing process in microwave field of a cellular glass aggregate using a recipe containing colored consumed drinking bottle, calcium carbonate (CaCO3) as an expanding agent, sodium borate (borax) as a fluxing agent and sodium silicate (Na2SiO3) as a binder is shown in the work. The main adopted technological measures were the advanced mechanical processing of residual glass at a grain dimension below 100 μm and especially the use of a high electromagnetic wave susceptible ceramic tube with a wall thickness reduced from 3.5 to 2.5 mm for the protection of the pressed glass-based mixture against the aggressive effect of microwave field and, in the same time, to achieve a preponderantly direct heating with electromagnetic waves. Of the tested variants, a recipe with 1.6 % calcium carbonate, 6 % borax, 8 % sodium silicate and the rest residual glass was determined to be optimal. The cellular glass aggregate had the bulk density of 0.22 g/cm3, heat conductivity of 0.079 W/m·K and compression strength of 5.9 MPa. The specific consumption of energy was very low (0.71 kWh/kg) below the range of reported values of the industrial processes consumption (between 0.74-1.15 kWh/kg).  

scholarly journals Cellular Glass Manufactured by Microwave Irradiation of Residual Glass, Eggshell and Borax

2021 ◽  
Vol 2 (5) ◽  
pp. 37-46
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Felicia Cosmulescu
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Compression Strength ◽  
Specific Energy Consumption ◽  
Sodium Borate ◽  
Insulation Material ◽  
Residual Glass ◽  
Cellular Glass ◽  
Heat Insulation Material ◽  
Added Water

The paper presents an improved method of manufacturing cellular glass using residual glass (91 %), sodium borate (5 %), eggshell waste (4 %) and added water (9 %). Compared to methods using eggshell as an expanding agent producing cellular glass with low compression strength, the technique adopted by the authors is original by the addition of sodium borate, which contributes to increasing the compression strength and the use of the unconventional electromagnetic wave heating method, which ensures very economical specific energy consumption. The optimal variant of cellular glass had the following characteristics: density of 0.40 g/cm3, porosity of 81 %, heat conductivity of 0.086 W/m·K, compression strength of 4.3 MPa and the cell dimension between 0.3-0.9 mm. The specific energy consumption of the process was 0.80 kWh/kg. The product has adequate features for using as a heat insulation material under conditions of quite high mechanical loading.  

Leaching Studies of Cement-Glass Package Containing Sodium Borate

1986 ◽  
Vol 84 ◽  
Author(s):  
Masahiro Okamoto ◽  
Koichi Chino ◽  
Tsutomu Baba ◽  
Tatsuo Izumida ◽  
Fumio Kawamura ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Liquid Waste ◽  
Sodium Borate ◽  
Pressurized Water Reactor ◽  
X Ray Diffraction ◽  
Adsorption Ability ◽  
Pressurized Water ◽  
X Ray ◽  
Solidification Reaction ◽  
Main Components

AbstractA new solidification technique using cement-glass, which is a mixture of sodium silicate, cement, additives, and initiator of the solidification reaction, was developed for sodium borate liquid waste generated from pressurized water reactor (PWR) plants. The cement-glass could solidify eight times as much sodium borate as cement could, because the solidifying reaction of the cement-glass is not hindered by borate ions.The reaction mechanism of sodium silicate and phosphoric silicate (initiator), the main components of cement-glass, was studied through X-ray diffraction and compressive strength measurements. It was found that three- dimensionally bonded silicon dioxide was produced by polymerization of the two silicates. The leaching ratio of cesium from the cement-glass package was one-tenth that of the cement one. This low value was attributed to a high cesium adsorption ability of the cement-glass and it could be theoretically predicted accordingly.

scholarly journals MICROWAVE MANUFACTURE OF GLASS FOAM BY COMBINED USE OF GRAPHITE AND CALCIUM CARBONATE AS FOAMING AGENTS

2021 ◽  
Vol 27 (1) ◽  
pp. 110-119
Author(s):  
LUCIAN PAUNESCU ◽  
SORIN MIRCEA AXINTE ◽  
MARIUS FLORIN DRAGOESCU ◽  
BOGDAN VALENTIN PAUNESCU ◽  
FELICIA COSMULESCU
Keyword(s):  
Calcium Carbonate ◽  
High Strength ◽  
Industrial Processes ◽  
Glass Waste ◽  
Foaming Agents ◽  
Combined Use ◽  
Variable Weight ◽  
Low Energy Consumption ◽  
Experimental Variant ◽  
Glass Foam

The paper presents experimental results obtained in the manufacturing process of high-strength glass foam by combined use of two solid foaming agents (calcium carbonate and graphite) in variable weight ratios. The originality of the work is applying the unconventional microwave heating method, unlike the conventional techniques currently used in similar industrial processes. The optimal experimental variant, composed of 89.1 % glass waste, 0.9% calcium carbonate, 1 % graphite and other additives, was sintered at 828 ºC with a very low energy consumption (0.73 kWh/kg). The main characteristics of the optimal product were apparent density of 0.39 g/cm3, thermal conductivity of 0.088 W/m·K and compressive strength of 3.6 MPa, being usable in fields that requires resistance to mechanical stress and relatively difficult environmental conditions.

scholarly journals Comparison of the Properties of Natural Sorbents for the Calcium Looping Process

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 548
Author(s):  
Krzysztof Labus
Keyword(s):  
Calcium Carbonate ◽  
Conversion Rate ◽  
Carbonate Rocks ◽  
Global Temperature ◽  
Industrial Processes ◽  
Thermal Pretreatment ◽  
Dsc Analysis ◽  
Natural Sorbents ◽  
Calcium Looping

Capturing CO2 from industrial processes may be one of the main ways to control global temperature increases. One of the proposed methods is the calcium looping technology (CaL). The aim of this research was to assess the sequestration capacity of selected carbonate rocks, serpentinite, and basalt using a TGA-DSC analysis, thus simulating the CaL process. The highest degrees of conversion were obtained for limestones, lower degrees were obtained for magnesite and serpentinite, and the lowest were obtained for basalt. The decrease in the conversion rate, along with the subsequent CaL cycles, was most intense for the sorbents with the highest values. Thermally pretreated limestone samples demonstrated different degrees of conversion, which were the highest for the calcium-carbonate-rich limestones. The cumulative carbonation of the pretreated samples was more than twice as low as that of the raw ones. The thermal pretreatment was effective for the examined rocks.

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 Effect of Sand Base Grade and Density of Moulding Sands with Sodium Silicate on Effectiveness of Absorbing Microwaves

2016 ◽  
Vol 16 (3) ◽  
pp. 103-108
Author(s):  
M. Stachowicz
Keyword(s):  
Relative Density ◽  
Sodium Silicate ◽  
Microwave Power ◽  
Power Loss ◽  
Electromagnetic Waves ◽  
Slot Line ◽  
Absorbed Power ◽  
High Silica ◽  
Sand Base ◽  
Reflected Power

Abstract In the paper, presented is a research on effectiveness of absorbing electromagnetic waves at frequency 2.45 GHz by unhardened moulding sands prepared of three kinds of high-silica base and a selected grade of sodium silicate. Measurements of power loss of microwave radiation (Pin) expressed by a total of absorbed power (Pabs), output power (Pout) and reflected power (Pref) were carried-out on a stand of semiautomatic microwave slot line. Values of microwave power loss in the rectangular waveguide filled with unhardened moulding sands served for determining effectiveness of microwave heating. Balance of microwave power loss is of technological and economical importance for manufacture of high-quality casting moulds and cores of various shapes and sizes. It was found that relative density influences parameters of power output and power reflected from samples of moulding sand placed in a waveguide. Absorption expressed by the parameter Pabs is not related to granularity of high-silica base: fine, medium and coarse. It was found that the semiautomatic microwave slot line supports evaluation of effectiveness of microwave absorption on the grounds of power loss measurements and enables statistic description of influence of relative density of the sandmix on penetration of electromagnetic waves in unhardened moulding sands.

scholarly journals A hydrated crystalline calcium carbonate phase: Calcium carbonate hemihydrate

Science ◽  
2019 ◽  
Vol 363 (6425) ◽  
pp. 396-400 ◽  
Author(s):  
Zhaoyong Zou ◽  
Wouter J. E. M. Habraken ◽  
Galina Matveeva ◽  
Anders C. S. Jensen ◽  
Luca Bertinetti ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Cement Industry ◽  
Industrial Processes ◽  
Magnesium Ions ◽  
Monoclinic Structure ◽  
Ambient Conditions ◽  
Amorphous Calcium Carbonate ◽  
Hydrated Crystal ◽  
Global Carbon

As one of the most abundant materials in the world, calcium carbonate, CaCO3, is the main constituent of the skeletons and shells of various marine organisms. It is used in the cement industry and plays a crucial role in the global carbon cycle and formation of sedimentary rocks. For more than a century, only three polymorphs of pure CaCO3—calcite, aragonite, and vaterite—were known to exist at ambient conditions, as well as two hydrated crystal phases, monohydrocalcite (CaCO3·1H2O) and ikaite (CaCO3·6H2O). While investigating the role of magnesium ions in crystallization pathways of amorphous calcium carbonate, we unexpectedly discovered an unknown crystalline phase, hemihydrate CaCO3·½H2O, with monoclinic structure. This discovery may have important implications in biomineralization, geology, and industrial processes based on hydration of CaCO3.

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