scholarly journals Sinthesis and Properties of Marble-Like Glass-Ceramics Using of Ash from Thermal Power Plants

2019 ◽  
pp. 173-178
Author(s):  
Yancho Hristov Hristov ◽  
Ganka Rumyanova Kolchakova
Keyword(s):  
Glass Ceramic ◽  
Power Plants ◽  
Bending Strength ◽  
Thermal Power ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Isothermal Hold ◽  
Thermal Power Plants ◽  
Secondary Phases ◽  
Glass Ceramic Materials

Color marble-like glass-ceramic materials were obtained through thermal treatment of glasses of the system CaO-Al2O3-SiO2 by using natural materials with the introduction of waste materials - ash from thermal power plants (TPP). The melting of the glass batch was in corundum crucibles at 1450oC with an isothermal hold of 60 min. The glasses obtained was fritted in distilled water and dried for 6 hours at 100oC, then completely crushed and divided into fractions with grain size of 0.8 mm, 1.0 mm, 2 mm, 2.5 mm and over 2.5 mm. It was found that the use of ash from TPP lead to higher values of degree of transformation (crystallization) than using base composition. Values of Avramy parameter’s in the range n=1,0 ÷ 1,6 are showed that crystallization of the glass frit is largely heterogeneous and crystal growing starts from the surface. The introduction of ash from TPP to native glasses carry out to significant reduction of energy of crystallization by Ес=289 kJ/mol to Ec=221 kJ/mol. The glass-ceramic materials were obtained through a one stage crystallization - 1050÷1070оС and an isothermal hold of 60 min., colored white, yellow brown to dark brown. The main crystalline phase in glass-ceramics is β-vollastonite with needle habit, size of crystals - ĺ = 40 ÷ 120 μm and d <5 μm in quantities 37 ÷ 42%. As secondary phases depending on the amount of ash have been identified - the anorthite, gehlenite and α-quartz with prismatic habit were appeared. The obtained glass-ceramic materials have a marble-like effect and technical parameters compared with natural granite and marble and have higher values of density, micro hardness, speed grinding, bending strength and chemical resistance. That’s why they can be used in construction such as lining materials.

New Silicate Glass-Ceramic Materials and Composites

2010 ◽  
Vol 68 ◽  
pp. 1-12 ◽  
Author(s):  
Dachamir Hotza ◽  
Antonio Pedro Novaes de Oliveira
Keyword(s):  
Silicate Glass ◽  
Glass Ceramic ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Crystalline Phases ◽  
Glass Ceramic Materials ◽  
Thermal And Electrical Properties ◽  
Large Production

New silicate glass-ceramic compositions have been investigated due to their interesting chemical, mechanical, thermal, and electrical properties. LZSA glass-ceramics based on -spodumene (Li2O•Al2O3•4-10SiO2) and zircon (ZrSiO4) crystalline phases have shown good chemical resistance, high bending strength as well as high abrasion resistance, when compared with traditional ceramic materials, and coefficient of thermal expansion from 4.6 to 9.110-6 °C-1. These features basically depend on the nature, size and distribution of the formed crystals as well as on the residual glassy phase. The nature of the formed crystalline phases and consequently the final properties can be controlled by modifying the chemical composition of the parent glass and also by adequate selection of the heat-treatment parameters. The classical fabrication of glass-ceramic materials consists on the preparation of monolithic glass components followed by heat treatments for crystallisation. However, this technology requires high investments and can be justified only for large production. A viable alternative could be the production of glass-ceramics processed from glass powders and consolidated by sintering using the same equipments of traditional ceramic plants. This work reports the manufacturing and characterization of glass-ceramic materials and composites processed by pressing, injection moulding, extrusion, casting, replication, and rapid prototyping.

scholarly journals Preparation of basalt-based glass ceramics

2003 ◽  
Vol 68 (6) ◽  
pp. 505-510 ◽  
Author(s):  
Branko Matovic ◽  
Snezana Boskovic ◽  
Mihovil Logar
Keyword(s):  
Optical Microscopy ◽  
Phase Analysis ◽  
Glass Ceramic ◽  
Glassy Phase ◽  
Raw Materials ◽  
Glass Ceramics ◽  
High Strength ◽  
Ceramic Materials ◽  
X Ray ◽  
Glass Ceramic Materials

Local and conventional raw materials?massive basalt from the Vrelo locality on Kopaonik mountain?have been used as starting materials to test their suitability for the production of glass-ceramics. Crystallization phenomena of glasses of the fused basalt rocks were studied by X-ray phase analysis optical microscopy and other techniques. Various heat treatments were used and their influences, on controlling the microstructures and properties of the products were studied with the aim of developing high strength glass-ceramic materials. Diopside CaMg(SiO3)2 and hypersthene ((Mg,Fe)SiO3) were identifies as the crystalline phases. The final products contained considerable amounts of a glassy phase. The crystalline size was in range of 8?480 ?m with plate or needle shape. Microhardness, crashing strength and wears resistence of the glass-ceramics ranged from 6.5?7.5, from 2000?6300 kg/cm2 and from 0.1?0.2 g/cm, respectively.

scholarly journals Utilization of discarded foundry sand (DFS) and inorganic waste from cellulose and paper industry for the manufacture of glass-ceramic materials

Cerâmica ◽  
2020 ◽  
Vol 66 (380) ◽  
pp. 413-420
Author(s):  
L. M. S. e Silva ◽  
R. S. Magalhães ◽  
W. C. Macedo ◽  
G. T. A. Santos ◽  
A. E. S. Albas ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Raw Materials ◽  
Paper Industry ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Foundry Sand ◽  
X Ray ◽  
Glass Ceramic Materials

Abstract Recycling has been pointed out as an alternative to the disposal of waste materials in industrial landfills. In the present study, the transformation of residues (discarded foundry sand - DFS, grits, and lime mud) in glass-ceramic materials is shown. The glasses were obtained by the melting/cooling method. The precursor materials, glasses, and glass-ceramics were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA). The glassy materials were milled, pelleted, and thermally treated at the crystallization temperatures given by DSC data to obtain the glass-ceramics (885, 961, and 1090 ºC). The main formed phases were cristobalite, α-wollastonite (parawollastonite), and β-wollastonite (pseudowollastonite). The glass-ceramics showed very low water absorption and apparent porosity (0.26 to 0.88 wt% and 0.66 to 1.77 vol%, respectively). The results confirmed that the studied residues can be used as raw materials for the manufacture of vitreous and glass-ceramic materials.

Crystallization and Mechanical Properties of Glass-Ceramic from Silicon Slag

2014 ◽  
Vol 953-954 ◽  
pp. 1643-1648
Author(s):  
Hang Li ◽  
Li Qiang Liu ◽  
Min Jing ◽  
Zhi Gang Wang ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Mechanical Performance ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Talcum Powder ◽  
X Ray ◽  
Glass Ceramic Materials ◽  
Spherical Grains

The glass-ceramic materials were produced from silicon slag with the addition of talcum powder and TiO2 by melting them in an electrically heated furnace and subsequent heat treatment at various temperatures and time. The microstructure and crystallization behaviors of glass–ceramics have been investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). With the increase of silicon slag content, the sequent precipitate phase is: krinovite Na (Mg1.9Fe0.1)Cr (SiO)3O, pseudobrookite Fe2TiO5 and anorthite Ca (Al2Si2O8), enstatite ferroan MgFeSi2O6, and albite Na (AlSi3O8). The shape of crystals was spherical grains. The glass–ceramic sample obtained from 70% silicon slag had the excellent mechanical performance including flexural strength of 200.45 MPa and Vickers micro hardness of 909.72 MPa.

scholarly journals Preparation and properties of Li2O-BaO-Al2O3-SiO2 glass-ceramic materials

2014 ◽  
Vol 8 (4) ◽  
pp. 203-210 ◽  
Author(s):  
Gamal Khater ◽  
Maher Idris
Keyword(s):  
Solid Solution ◽  
Water Absorption ◽  
Glass Ceramic ◽  
Density Measurement ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
Glass Ceramic Materials

The crystallization of some glasses, based on celsian-spodumene glass-ceramics, was investigated by different techniques including differential thermal analysis, optical microscope, X-ray diffraction, indentation, microhardness, bending strengths, water absorption and density measurement. The batches were melted and then cast into glasses, which were subjected to heat treatment to induce controlled crystallization. The resulting crystalline materials were mainly composed of ?-eucryptite solid solution, ?-spodumene solid solution, hexacelsian and monoclinic celsian, exhibiting fine grains and uniform texture. It has been found that an increasing content of celsian phase in the glasses results in increased bulk crystallization. The obtained glass-ceramic materials are characterized by high values of hardness ranging between 953 and 1013 kg/mm2, zero water absorption and bending strengths values ranging between 88 and 126MPa, which makes them suitable for many applications under aggressive mechanical conditions.

Transformation toughening of glass ceramics

1987 ◽  
Vol 2 (6) ◽  
pp. 801-804 ◽  
Author(s):  
D. R. Clarke ◽  
B. Schwartz
Keyword(s):  
Glass Ceramic ◽  
Tetragonal Zirconia ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Nucleation Event ◽  
Transformation Toughening ◽  
Glass Ceramic Materials ◽  
Polycrystalline Ceramic ◽  
Cordierite Glass ◽  
Processing Techniques

The utilization of transformation toughening has hitherto been restricted to increasing the fracture resistance of polycrystalline ceramic materials. Although a number of investigators have attempted to extend the concept to toughening glasses and glass ceramics with tetragonal zirconia, no successful reports have been published. It is argued that the approaches employed are inevitably limited primarily because they do not take into account the necessity of nucleating the tetragonal-to-monoclinic transformation away from the crack tip itself. By concentrating on the nucleation event and using standard ceramic processing techniques, it has been demonstated that transformation toughening can be used to increase the toughness of glass-ceramic materials, and this approach is illustrated by increasing the fracture toughness of a cordierite glass ceramic.

scholarly journals Cutting inserts made of glass and glass ceramics

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Bernd Breidenstein ◽  
Dominik Müller-Cramm ◽  
Nils Vogel
Keyword(s):  
Glass Ceramic ◽  
Raw Materials ◽  
Cutting Tools ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Glass Ceramic Materials ◽  
First Results ◽  
Cutting Inserts ◽  
The Way

AbstractAgainst the background of the increasing cost and scarcity of raw materials that are required for the manufacture of cutting tools, the question of alternative cutting materials arises. Glasses and glass ceramics represent a possibility for this, the use of which has hardly been considered so far. This thesis is devoted to the question of whether cutting tools can be made from glass and glass ceramic materials at all. In addition, the question of how such tools can be used for which purposes is dealt with. First results on both questions are presented. The grinding of indexable inserts from the materials examined was possible without breaking corners and edges. Plastics can be easily machined with the tools produced. When machining aluminum, however, the tools made of glass fail completely, while those made of glass–ceramic show good results here too. These first results are intended to pave the way for further research in this area.

scholarly journals Application of the final flotation waste for obtaining the glass-ceramic materials

2017 ◽  
Vol 49 (4) ◽  
pp. 431-443
Author(s):  
Mira Cocic ◽  
Mihovil Logar ◽  
Suzana Eric ◽  
Visa Tasic ◽  
Snezana Devic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Glass Ceramic ◽  
Construction Materials ◽  
Glass Ceramics ◽  
Propagation Speed ◽  
Ceramic Materials ◽  
Time Duration ◽  
Good Thermal Stability ◽  
Glass Ceramic Materials ◽  
Main Component

This work describes the investigation of the final flotation waste (FFW), originating from the RTB Bor Company (Serbia), as the main component for the production of glass-ceramic materials. The glass-ceramics was synthesized by the sintering of FFW, mixtures of FFW with basalt (10%, 20%, and 40%), and mixtures of FFW with tuff (20% and 40%). The sintering was conducted at the different temperatures and with the different time duration in order to find the optimal composition and conditions for crystallization. The increase of temperature, from 1100 to 1480?C, and sintering time, from 4 to 6h resulted in a higher content of hematite crystal in the obtained glass-ceramic (up to 44%). The glass-ceramics sintered from pure FFW (1080?C/36h) has good mechanical properties, such as high propagation speed (4500 m/s) and hardness (10800 MPa), as well as very good thermal stability. The glass-ceramics obtained from mixtures shows weaker mechanical properties compared to that obtained from pure FFW. The mixtures of FFW with tuff have a significantly lower bulk density compared to other obtained glass-ceramics. Our results indicate that FFW can be applied as a basis for obtaining the construction materials.

Production of the Aluminosilicate Ceramic Materials Using Fly Ash from Thermal Power Plants (TPP)

2020 ◽  
Vol 61 (3) ◽  
pp. 281-284
Author(s):  
M. Kh. Rumi ◽  
Sh. K. Irmatova ◽  
Sh. A. Fayziev ◽  
E. M. Urazaeva ◽  
E. P. Mansurova ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Ceramic Materials ◽  
Thermal Power Plants

scholarly journals Innovative directions of development of ceramic materials for dentistry

2021 ◽  
pp. 19-25
Author(s):  
O.V. Savvova ◽  
G.K. Voronov ◽  
O.I. Fesenko ◽  
Yu.O. Smirnova ◽  
E. Bairamov
Keyword(s):  
High Temperature ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Oxide Glass ◽  
Lithium Silicate ◽  
Silicate System ◽  
Advantages And Disadvantages ◽  
Glass Ceramic Materials

The need to improve the level of dental health of the population of Ukraine was identified. The prospects for the use of ceramic prostheses to provide quality medical care in dentistry have been established. An analytical review of various types of ceramic and glass-ceramic materials used as dental prostheses for tooth replacement: porcelain, alumina, zirconium oxide, glass-ceramics based on leucite and lithium disilicate and mica with the addition of fluorides. Peculiarities of the structure and operational properties of ceramic and glass-ceramic materials for dentistry have been identified, their advantages and disadvantages have been established. The effectiveness of the use of glass-ceramic materials based on lithium disilicate for dental prosthetics is substantiated. The basic lithium silicate system was selected and glasses for obtaining glass-ceramic crowns based on lithium disilicate by the method of high-temperature pressing and calcium phosphate-silicate system for obtaining glass-ceramic coatings were synthesized. The methodological approach to the development of glass-ceramic prostheses based on lithium disilicate is determined. The limits of the compositions of oxide components are determined and raw materials for the synthesis of the glass matrix are selected. The technological parameters of melting (T = 1350 – 1400ºС) and heat treatment with simultaneous formation of products (stage of nucleation T = 600 – 650ºС, τ = 30 – 60 min; stages of formation T = 900ºС, τ ≈ 20 min) are selected. The composition of fluoroapatite glass-ceramic coating for glazing of glass-ceramics and the mode of its firing (T = 800 – 850ºС, τ ≈ 1,0 – 1,5 min) were determined. The serviceability of the developed glass-ceramic samples DL st.glass, which were obtained by the technology of high-temperature pressing, are determined. The comparative analysis of glass-ceramic prostheses for dentistry allowed to establish that the operational properties of the developed glass-ceramic prostheses according to ISO 6872:2015 are at the level of world analogues. This will allow them to successfully compete in the Ukrainian market with well-known foreign counterparts and help ensure the social priorities of the state in the field of health care.

Sign in / Sign up

Export Citation Format

Share Document