Development Of Glass-ceramics Research Articles

Development of glass-ceramics from Soda lime silica glass waste with addition of kaolin and coloring oxide for Turquoise’s imitation

Turquoise, a hydrated phosphate of copper and aluminum, is an opaque, blue-to-green mineral with the chemical formula CuAl6(PO4)4(OH)80.4 H2O. Owing to its unique hue, turquoise is rare and valuable, and it has been appraised as a gemstone for thousands of years. However, with high porosity, low specific gravity, fracturable, and low hardness of just under six or slightly more than window glass, treatments are required before use as jewelry. Nowadays, imitations, and synthetics from glass, plastic, or pressed turquoise powder bonded with resin, are generally found in the market. In our present study, we aim to investigate an alternative method to form glass-ceramic for turquoise imitation by using a direct sintering method based on the soda-lime-silica glass waste with kaolin mixer and coloring oxide additives. In the preparation, the pre-mixed powders were poured into a stainless-steel die, then, the die was brought to the pressing machine for sample forming. A conventional furnace was applied for heating the samples to ∼1000 °C with a soaking time of 4 h. The obtained ingots were characterized by several techniques. The chemical compositions were determined by the Energy Dispersive X-ray Fluorescence (ED-XRF), and their chemical structures were evaluated by the X-ray diffractometer. Meanwhile, their chemical fingerprints were obtained by Raman spectroscopy. As for comparison, the natural turquoise, as well as the commercial imitation samples, selected from the local market were undergone the same characterization. We have found that with the proper content of the metal oxide additives, the products in unique blue and brown-turquoise appearances can be formed and cut to decorate the jewelry set for the niche market. Thus, an alternative method for recycling soda lime-silica waste glass based on a single-step sintering process at relatively low temperature enabled jewelry applications.

Development of Glass-Ceramics and Their Application

Development of Glass-Ceramics and Their Application

Development of Glass-Ceramics from Soda Lime Silica Glass Waste by Direct Sintering Method for Opal Imitation

Natural opal, an amorphous, hydrous form of silica (SiO2-n-H2O), has been one of the favored precious gemstones for many centuries. Though beautiful, opal is very fragile and is damaged quite easily. Thus, opals of all varieties have been synthesized experimentally and commercially. The objective of this project was to synthesize and to compare crystalline opals. In this work, the development of powder sintered glass ceramics process based on soda lime silica glass waste with metal oxide powder enable jewelry applications. The substantial viscous flow of the glass led to dense products for rapid treatments at relatively low temperatures (900–1,000°C), whereas glass/metal powder interactions resulted in the formation of color agent crystals, provide enhancing optical properties. Several techniques were applied for characterization of the ingots. The chemical analysis was performed by Energy Dispersive X-ray Fluorescence (ED-XRF). The mineralogical compositions of the samples were determined by X-ray diffraction analysis. Raman spectroscopy was applied for optical characterization. The results were compared with a natural common opal. The present investigation demonstrated that the common opal with both color and colorless appearance can be synthesized by the technique, as the crystalline phase of opal structure was identified by XRD measurement. There is a great potential for such materials with novel functionalities for artificial gemstone application, i.e. opal forming.

Glass-ceramics for nuclear-waste immobilization

Abstract

Development of glass-ceramics from soda lime silica glass waste by sintering method for opal imitation

Natural opal, an amorphous, hydrous form of silica (SiO2-n-H2O), has been one of the favored precious gemstones for many centuries. Though beautiful, opal is very fragile and is damaged quite easily. Thus, opals of all varieties have been synthesized experimentally and commercially. The objective of this project was to synthesize and to compare crystalline opals. In this work, the development of powder sintered glass ceramics process based on soda-lime-silica glass waste with silica powder enable jewelry applications. The substantial viscous flow of the glass led to dense products for rapid treatments at relatively low temperatures (900–1,000°C), whereas glass/metal powder interactions resulted in the formation of color agent crystals, provide enhancing optical properties. There is a great potential for such materials with novel functionalities for artificial gemstone application, i.e. opal forming. Several techniques were applied for characterizing the ingots. The chemical analysis was performed by Energy Dispersive X-ray Fluorescence (ED-XRF). The mineralogical compositions of the samples were determined by X-ray diffraction analysis. Raman spectroscopy was applied for optical characterization. The results were compared with a natural common opal. The present experiments demonstrated that the common milky opal can be synthesized by the technique, as the crystalline phase of opal structure was identified by XRD measurement.

Development of glass-ceramics from boron containing waste and meat bone ash combinations with addition of waste glass

Glass-ceramic materials represent a great resource for environmental cleanup, because they can stabilize pollutants by vitrification and, at the same time, they may present remarkable mechanical and functional properties enabling novel applications. In this paper, different mixes of three different industrial wastes, namely boron waste (BW), meat bone and meal ash (MBM) and recycled soda lime silica glass (SLG) were prepared by considering the combined effects of thermal cycle requirement, particle sizes of the selected wastes and amount (content) of boron waste. Glass-ceramics were prepared from selected waste mixtures and the physical and mechanical properties of the obtained glass-ceramics were measured. The results underline that boron containing waste-derived glass-ceramics are attractive for applications as gas concrete blocks or as an additive in new generation insulation ceramics.

Glass-ceramics obtained by the recycling of end of life cathode ray tubes glasses

This work is concerned with open-loop recycling of end of life Cathode Ray Tubes glass (an unsolved problem when considering that in Europe almost 90% of EOL electronic goods is disposed of in landfills), focusing on the development of glass-ceramics from panel or funnel glass with dolomite and alumina, and the evaluation of the tendency towards crystallisation with particular attention on composition and thermal treatment. Glasses were melted at a temperature of about 1500 °C and transformed into glass-ceramics by different thermal treatments (900 °C to ∼1100 °C temperature range and 0.5 to ∼8 h soaking time). By using the evaluation of thermal, mineralogical and microstructural data it has been pointed out that a good degree of crystallisation is reached at about 1000 °C and with a high proportion of waste glass (50–75%) if 40–45% of CaO and MgO bearer (dolomite) is introduced. In this way alkaline and alkaline-earth silicate and aluminosilicate mainly develop probably with a surface mechanism.

Development of glass-ceramics by sintering and crystallization of fine powders of calcium-magnesium-aluminosilicate glass : Tulyaganov, D. U. et al. Ceramics International, 2002, 28, (5), 515–520. (In Japanese)

Development of glass-ceramics by sintering and crystallization of fine powders of calcium-magnesium-aluminosilicate glass : Tulyaganov, D. U. et al. Ceramics International, 2002, 28, (5), 515–520. (In Japanese)

Development of glass-ceramics by sintering and crystallization of fine powders of calcium-magnesium-aluminosilicate glass

Natural raw materials normally used in the ceramic and glass industry were studied for the production of calcium–magnesium–aluminosilicate glass or glass-ceramic materials. Sintering and crystallization processes of fine powders of parent glass with chemical composition (wt.%) 46.00 SiO 2, 15.90 Al 2O 3, 1.20 Fe 2O 3, 0.42 TiO 2, 23.50 CaO, 9.37 MgO, 0.04 Na 2O, 0.98 K 2O, 1.95 P 2O 5 and 0.35 CaF 2 were studied. Crystallization kinetics of glass-ceramics was carefully examined by DTA, XRD, and SEM techniques and by dilatometric studies. The desired sequence of events, i.e. nucleation, sintering and devitrification occurred by heat-treating the glassy powder. However, crystallization of the parent glass did not follow phase diagram predictions, since anomalous appearance of akermanite phase was detected along with expected anorthite and diopside precipitation. A reasonable explanation for this unexpected observation is given.

Development of glass-ceramics from glass cullet and concrete sludge

Development of glass-ceramics from glass cullet and concrete sludge

Influence of P 2O 5, AgNO 3, and FeCl 3 on color and translucency of lithia-based glass-ceramics

Objectives. The objective of this study was to characterize the influence of various metals, metal compounds, and P 2O 5 as a nucleating agent on the color and translucency of a Li 2OAl 2O 3CaOSiO 2 glass-ceramic. Methods. Glass frits of Li 2OAl 2O 3CaOCaOSiO 2 (LACS), LACS with 1 mol% P 2O 5 (LACSP), and/or LACS with one of 16 colorants were melted, poured into a cylindrical graphite mold, cut into disks, annealed, nucleated, crystallized, and annealed again. Ten translucency measurements of each of five disks were made using a tristimulus colorimeter and a D65 standard CIE illuminant. The color of each disk was analyzed using the CIE L ★a ★b ★ color space system (1976) as a function of colorant, colorant concentration, and P 2O 5. Results. Mean L ★ values of glass-ceramic disks ranged from 63.5 for LACS containing 6.2 mmol% FeCl 3 (LACSP-6.2Fe) to 84.1 for LACS. No significant difference (p > 0.05) was found between the mean L ★ values for LACS, LACSP, and LACS with 0.19 mmol% AgNO 3 (LACS-0.19Ag). The mean contrast ratio of glass-ceramic specimens ranged from 0.42 (LACS and LACS-1.0Fe) to 0.98 (LACS-0.78Ag). Mean color difference values varied from 5.8 (LACSP-1.0Fe vs. LACS) to 36.3 (LACSP-0.78Ag vs. LACSP). Significance. The results of this study indicate that, because certain colorants in glass-ceramics affect opacity as well as hue and chroma, the development of glass-ceramics should be simplified by: 1) employing a nucleating agent that does not affect hue or chroma significantly, 2) controlling fixed levels of translucency consistent with mechanical and physical property requirements, and 3) varying the hue and chroma by means of colorants that do not affect the crystallization process. This implies that the volume fraction and mean size of crystals must be controlled, since the translucency or opacity of glass-ceramics is associated with scattering of light at the interfaces between adjacent crystals, and between crystals and the glass phase because of differences in refractive indices (McMillan, 1979a).

Development of glass ceramics in China

A historical review of glas ceramics in China is given. Glass ceramics in the systems including Li 2OAl 2O 3SiO 2, BaOAl 2O 3SiO 2, MgOAl 2O 3SiO 2, CaOMgOAl 2O 3SiO 2, ZnOAl 2O 3SiO 2, Na 2OAl 2O 3SiO 2, R 2OCaOMgOAl 2O 3SiO 2, LiO 2K 2OMgOAl 2O 3SiO 2F, CaOP 2O 5, etc. were investigated by many Chinese scientists. As a result, the progress of modern techniques and engineering was promoted. The mechanism of crystallization, the internal friction change in crystallization, and the relationship between phase separation and crystallization, were also attended to in order to approach the theoretical rule in different production processes. Various articles of glass ceramics were manufactured. The properties and applications of two different glass ceramics, fluoro-lepidolite glass ceramics and PbTiO 3-based ferroelectric glass ceramics, were introduced. The author investigated the current situation of research work concerned with the comprehensive utilization of minerals in glass ceramics making. Lepidolite-based glass ceramics is a modern material which was prepared by using refined lithium mica as the major raw material. The physico-chemical properties were described and the unique machinable properties were discussed. In another case, a new type of piezoelectric and pyroelectric material made from glass ceramics was reported. According to the properties, it shows that the material which is comparable to corresponding ceramics open positive prospects concerning future applications. It is predicted that the investigation of inorganic composites related to glass ceramics may be of great significance in the future.

Perspective of the development of bioactive glass ceramics for biomedical applications

The development of new materials for application in human medicine, especially for replacement of bones or other tissue, is a young field of research in the world. New results lead to extra-ordinary progress in human medicine. Necessary lines of development of bio-materials are mentioned. As an example, the development of a glass ceramic, which is both machinable and highly bioactive, is described.