Unconventionally Made-Cellular Glass Aggregate

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).

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

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.

Tarawera Volcanic Complex

<p>The Tarawera Volcanic Complex is situated on the south eastern side of the Okataina Volcanic Centre, and is an association of rhyolite domes, flows and tephra, and basalt scoria. Twelve rhyolite domes are described, and using evidence obtained from the good internal sections available, the general structure of volcanic domes is discussed. Tephra stratigraphy of the Tarawera-Rerewhakaaitu region is described and by relating stratigraphy on the mountain to this tephra, four major eruptions can be recognized. A sequence of events for the Kaharoa eruption about 1020 A.D. can be postulated. The Tarawera eruption in 1886, however, was observed, and from the eye witness accounts, together with present day field evidence, a detailed account can be written. All the rocks of the Complex are described petrographically, mineralogically, and in some cases petrochemically. Twelve new full analyses; nine partial analyses of plagioclase, and eight partial analyses of residual glass are given, and the relationship of these is illustrated by variation diagrams. Finally, the origins of the acid and basic rocks of the Complex are discussed, and a hypothesis for the occurrence of the two lava types is given.</p>

Tarawera Volcanic Complex

<p>The Tarawera Volcanic Complex is situated on the south eastern side of the Okataina Volcanic Centre, and is an association of rhyolite domes, flows and tephra, and basalt scoria. Twelve rhyolite domes are described, and using evidence obtained from the good internal sections available, the general structure of volcanic domes is discussed. Tephra stratigraphy of the Tarawera-Rerewhakaaitu region is described and by relating stratigraphy on the mountain to this tephra, four major eruptions can be recognized. A sequence of events for the Kaharoa eruption about 1020 A.D. can be postulated. The Tarawera eruption in 1886, however, was observed, and from the eye witness accounts, together with present day field evidence, a detailed account can be written. All the rocks of the Complex are described petrographically, mineralogically, and in some cases petrochemically. Twelve new full analyses; nine partial analyses of plagioclase, and eight partial analyses of residual glass are given, and the relationship of these is illustrated by variation diagrams. Finally, the origins of the acid and basic rocks of the Complex are discussed, and a hypothesis for the occurrence of the two lava types is given.</p>

Effect of Feldspar Substitution by Basalt on Pyroplastic Behaviour of Porcelain Tile Composition

This work aims to evaluate the effects of feldspar substitution by basalt on porcelain tile composition with respect to its porosity, flexural strength, and pyroplastic deformation. Three ceramic formulations with different amounts of feldspar substituted with basalt, 50% (C1), 75% (C2), and 100% (C3), were evaluated at three different temperatures, 1200, 1220, and 1240 °C. Specifically, the effect of replacing feldspar with basalt on the pyroplastic deformation of ceramic bodies was analysed using optical fleximetry. The porosity of C1 at 1200 °C was 19.3 ± 2.9%, while that of composition C3 was 22.2 ± 0.7% at 1240 °C. The flexural strength was strongly influenced by the temperature. For C1 at 1200 and 1240 °C, flexural strengths of 11.1 ± 0.6 and 22.2 ± 1.9 MPa, respectively, were obtained. Regarding fleximetry, thermal deformation decreased with an increase in the amount of feldspar substituted with basalt. It was observed that C2 and C3 deformed less at high temperatures than the other combinations of compositions and temperature, probably owing to the lower amount of residual glass phase present during cooling. Compositions with higher substitution amounts of basalt (i.e., C2 and C3) exhibited more stable thermal behaviour than C0.