scholarly journals Effects of microsilica content on microstructure and strength of lightweight castable refractories containing porous corundum-spinel aggregate

2009 ◽  
Vol 41 (3) ◽  
pp. 275-281 ◽  
Author(s):  
W. Yan ◽  
N. Li ◽  
B.Q. Han
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
Average Pore Size ◽  
Mercury Porosimetry ◽  
High Strength ◽  
Apparent Porosity ◽  
Liquid Content ◽  
Average Pore ◽  
Crushing Strength ◽  
Liquid Sintering

High-strength, lightweight castable refractories based on spinel were prepared by introducing porous corundum-spinel aggregate and appropriate microsilica. The effects of microsilica content on microstructure and properties of lightweight castable refractories were investigated using SEM, XRD, mercury porosimetry measurements and FactSage thermochemical software. It's found that microsilica was almost dissolved into a liquid phase at high temperature, which promoted liquid sintering. With increasing microsilica content, the matrices became denser and average pore size of matrices increased, then apparent porosity decreased, crushing strength increased and content of liquid phase in castables at 1600?C increased. The appropriate microsilica content is 0.65 to 1.95 wt%, which reaches to a compromise among apparent porosity (33-38%), crushing strength (82-125MPa) and liquid content (1.80~4.97 wt%).

The Preparation of High-Strength and Micropore Lightweight Bauxite Aggregate by In Situ Polymerization and Decomposition

2011 ◽  
Vol 194-196 ◽  
pp. 2135-2139
Author(s):  
Yi Neng Fang ◽  
Hua Zhi Gu ◽  
Yun Sheng Fen ◽  
Lin Jun Wang ◽  
Yan Jing Li
Keyword(s):  
Phase Composition ◽  
Pore Size ◽  
Aluminium Hydroxide ◽  
Average Pore Size ◽  
High Strength ◽  
Organic Polymer ◽  
Low Grade ◽  
Pore Former ◽  
Average Pore

High-strength and micropore lightweight bauxite aggregate was fabricated by low grade raw bauxite powder, aluminium hydroxide powder and organic polymer (OP). OP was used as consolidator, binder and pore former and aluminium hydroxide was used as pore former. The influence of OP and aluminium hydroxide content on the property of the samples was studied. The phase composition and the microstructure of the sintered samples were characterized by XRD, SEM and the pore size distribution was measured by mercury porosimety. The results demonstrate that the bulk density of the samples decreases linearly and the apparent porosity of the samples increases gradually with the addition of OP. The lowest density reached 1.13g/cm3when adding 35% OP and 10% Al(OH)3. The average pore size is around 5μm, and increases with the addition of OP increased. The XRD showed the main phase of the sample is mullite and some little amount of corundum.

scholarly journals Improving High-Alumina Iron Ores Processing via the Investigation of the Influence of Alumina Concentration and Type on High-Temperature Characteristics

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 802
Author(s):  
Yuxiao Xue ◽  
Jian Pan ◽  
Deqing Zhu ◽  
Zhengqi Guo ◽  
Congcong Yang ◽  
...  
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
High Strength ◽  
Free State ◽  
High Alumina ◽  
Iron Ores ◽  
Alumina Concentration ◽  
Temperature Characteristics ◽  
Al2o3 Concentration ◽  
Iron Grade

Aiming at the effective utilization of the abundant high-alumina iron ores with low iron grade, the influence of alumina concentration and type on high-temperature characteristics was clarified based on the analyses of eight typical iron ores. The results indicate that high-temperature characteristics of iron ores in various alumina types are different. Higher Al2O3 concentration is deleterious to assimilability and liquid phase fluidity, but the influence extent of each alumina type is substantially different. Kaolinite (Al2O3·2SiO2·2H2O) contributes to correspondingly better assimilability, followed by hercynite (Fe(Fe, Al)2O4), gibbsite (Al(OH)3), diaspore (AlO(OH)), and free state alumina (Al2O3) in turn. Diaspore promotes relatively higher liquid phase fluidity, followed by kaolinite, free state alumina, and hercynite, while gibbsite possesses the maximum adverse impact. Kaolinite and hercynite are more beneficial to form dendritic or acicular silico-ferrite of calcium and alumina (SFCA) with high strength due to the better reactivity, and gibbsite and diaspore lead to more formation of relatively lower strength lamellar or tabular SFCA, while free state alumina is preferable to form disseminated SCFA with rather poorer strength. Kaolinite and hercynite are the most desirable alumina types for sintering rather than free state alumina.

scholarly journals EFFECT OF AGAR-KAOLIN INTERACTION IN GELCASTING MIXTURES ON FORMING OF ALUMINA MEMBRANE SUPPORT

2018 ◽  
Vol 80 (3-2) ◽  
Author(s):  
Kowit Lertwittayanon
Keyword(s):  
Optimum Condition ◽  
Relative Density ◽  
Pore Size ◽  
Rough Surface ◽  
Sintering Temperature ◽  
Average Pore Size ◽  
High Strength ◽  
Asymmetric Membrane ◽  
Alumina Membrane ◽  
Average Pore

Disc alumina membrane supports were formed through agar gelcasting method. The agar gelcasting was expected to be environmentally-friendly forming technique using simple equipment. Final agar amounts (0.25 – 0.75wt%) in gelcasting mixtures were varied to find the optimum condition of shaping and the desired microstructure of sintered supports. The gelcasting mixtures were prepared from non-reactive grade Al2O3 and porcelain at the ratio of 98.5:1.5 by weight. The porcelain addition allowed the membrane support to have high strength at lower sintering temperature. When the final agar amounts increased from 0.25 to 0.75wt%, the dried, gelcast supports tended to have rough surface and subsequently resulting in crack. TGA profiles confirmed that there was interaction between agar chains and kaolin particles on cooling the gelcast supports leading to different microstructures after sintering. The final agar amount of 0.5 wt% provided the highest porosity of 48.9% and the highest relative density of 61.5%. Additionally, the average pore size of 1.5 µm was obtained at the final agar amount of 0.5 wt% suitable for using as asymmetric membrane support or microfiltration membrane.   

Obtaining Ceramic Filter from Rice Husk and Kaolinitic Clay

2014 ◽  
Vol 802 ◽  
pp. 232-238 ◽  
Author(s):  
R.P.A. Souza ◽  
F.V. Motta ◽  
R.G. Carvalho ◽  
W. Acchar ◽  
E. Harima ◽  
...  
Keyword(s):  
Pore Size ◽  
Rice Husk ◽  
Average Pore Size ◽  
Mercury Porosimetry ◽  
Standard Technique ◽  
Ceramic Filter ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Kaolinitic Clay

In this study, different compositions based on rice husk carbon and kaolinitic clay aimed at obtaining ceramic filter were studied. Three compositions of 40, 60 and 80% rice husk of the total mass were prepared. The specimens were uniaxially compressed in rectangular shape at pressure of 28 MPa and were sintered at temperatures of 1100oC, 1150oC and 1200oC for 1 h. The sintered samples were characterized according to standard technique for linear shrinkage, water absorption, apparent porosity and flexural strength. Scanning Electron Microscopy (SEM) was also performed to check the average pore size, and X-Ray Diffraction (XRD) to verify existing crystalline phases, chemical analysis and mercury porosimetry. The X-ray diffraction results showed mostly alpha quartz peaks and mullite after sintering. Mercury porosimetry showed porosity of 44.33% and average pore size of approximately 8.33 μm for sample with 60% rice husk sintered at 1200°C.

scholarly journals Synthesis of Porous Biomimetic Composites: A Sea Urchin Skeleton Used as a Template

2021 ◽  
Vol 11 (19) ◽  
pp. 8897
Author(s):  
Nikolay P. Shapkin ◽  
Evgeniy K. Papynov ◽  
Alexandr E. Panasenko ◽  
Irina G. Khalchenko ◽  
Vitaly Yu. Mayorov ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Raw Materials ◽  
Average Pore Size ◽  
Mercury Porosimetry ◽  
Ceramic Composites ◽  
Original Method ◽  
Original Structure ◽  
Average Pore ◽  
Inverted Structure ◽  
Porous Composites

The paper presents an original method for the template synthesis of biomimetic porous composites using polyferrophenylsiloxane (PFPS) and the skeleton of the sea urchin Strongylocentrotus intermedius as a structuring template. The study aimed to form an organosilicon base of a composite with an inverted structure relative to the original structure of the sea urchin shell with a period of structure movement of about 20 µm and ceramic composites fabrication with the silicate base with an average pore size distribution of about 10 μm obtained by the reaction of PFPS with the inorganic base of the sea urchin test under conditions of calcination at 1000 °C followed by acid etching. The composition and morphology of the obtained composites were investigated by IR, XRD, XPS, EDX, and SEM techniques and by mercury porosimetry; the parameters of the porous structures depend on the selected methods of their synthesis. The proposed method is of fundamental importance for developing methods for the chemical synthesis of new biomimetics with a unique porosity architecture based on environmentally friendly natural raw materials for a vast practical application.

scholarly journals Quality Assessment of SCGPC using Ultra-Sonic Pulse Velocity at High Temperature

2019 ◽  
Vol 8 (12) ◽  
pp. 810-815
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Pore Size ◽  
Average Pore Size ◽  
Pulse Velocity ◽  
Moisture Loss ◽  
Geopolymer Concrete ◽  
Lower Strength ◽  
Average Pore ◽  
Significant Decrement

This paper presents the effect of high temperature on compressive strength and ultra-sonic pulse velocity of self compacting geopolymer concrete (SCGPC) mixes with varying molarities viz., 8M, 10M and 12M. At different ages, the specimens were kept at a high temperature (100, 200, 400, 600 and 800oC) for 2 hours and then testing of the specimens was carried out. Prior to compressive strength of test specimens, ultra-sonic pulse velocity (UPV) test was performed after 7, 28 and 56 days of curing. From the results, it is revealed that the compressive strength and UPV results of SCGPC were decreased with the increase in temperature from 1000C to 8000C in all curing periods. Finally, it is concluded that the significant decrement in compressive strength and UPV up to 8000C is mainly due to continuous moisture loss from the specimens and increase in the average pore size, which produce the lower strength and pulse velocity of the concrete.

Production and Characterization of Porous Titanium Applied in Biomaterial

2017 ◽  
Vol 899 ◽  
pp. 179-184 ◽  
Author(s):  
Pâmela Karina S. Bomfim ◽  
Israel A. Cruz ◽  
Cátia Fredericci ◽  
Maurício David Martins das Neves
Keyword(s):  
Average Pore Size ◽  
High Strength ◽  
Porous Titanium ◽  
Alpha Phase ◽  
High Reactivity ◽  
Tissue Growth ◽  
Bending Test ◽  
Average Pore ◽  
Three Point Bending ◽  
Relevant Fact

The development of materials with a porous titanium surface has been widely studied in the field of biomaterials due to the excellent biocompatibility, high corrosion resistance and combination of high strength with low density. Another relevant fact is that porosity allows bone tissue growth. However, the high reactivity in liquid state ends up hindering titanium fusion, so an alternative is the powder metallurgy (PM).The aim of this work was to produce porous titanium samples by conventional PM. Porous samples was characterized by porosity and microstructure (optical microscopy - OP and scanning electron microscopy SEM), crystaline phase (X-ray diffraction –XRD), mechanical properties (three point bending test) and cytotoxic test. The results showed the presence of alpha phase, a decrease in the elasticity modulus, increase in average pore size and samples exhibited no toxic effects.

INFLUENCE OF FORCED CONVECTION IN LIQUID INSIDE THE TIN ON DURATION OF STERILIZATION IN THE COURSE OF FISH PROCESSING

2017 ◽  
pp. 137-144
Author(s):  
Gennadiy Valentinovich Alexeev ◽  
Elena Igorevna Verboloz
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
Forced Convection ◽  
Thermal Process ◽  
Processing Time ◽  
Fish Processing ◽  
Study Results ◽  
Equipment Modernization ◽  
Bottom To Top

The article focuses on the process of intensive mixing of liquid phase in the tin during high-temperature sterilization, i.e. sterilization when temperature of the heat carrier reaches 150-160°C. It has been stated that for intensification of the thermal process during sterilization of tinned fish with liquid filling it is preferable to turn a tin from bottom to top. This operation helps to increase the driving power of the process and to shorten warming time. Besides, high-temperature sterilization carried out according to experimental modes, where the number of tin turnovers is calculated, greatly shortens processing time and improves quality of the product. In this case there is no superheating, all tins are evenly heated. The study results will contribute to equipment modernization and to preserving valuable food qualities.

PYROTOOL A

Alloy Digest ◽  
1971 ◽  
Vol 20 (4) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Good Ductility ◽  
Extrusion Dies ◽  
Temperature Performance

Abstract PYROTOOL A has been designed to display high strength and good ductility at temperatures up to 1200 F. It is used for high-temperature tooling, extrusion dies, liners, dummy blocks, forging dies, mandrels, holders, etc. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-47. Producer or source: Carpenter.

INCONEL ALLOY 722

Alloy Digest ◽  
1965 ◽  
Vol 14 (4) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Base Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Age Hardening ◽  
Nickel Base Alloy ◽  
Inconel Alloy ◽  
Temperature Performance ◽  
Nickel Base

Abstract INCONEL Alloy 722, formerly Inconel W alloy, is a high strength, high-temperature nickel-base alloy responding to age hardening heat treatments for maximum properties. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-100. Producer or source: Huntington Alloy Products Division, An INCO Company.

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