scholarly journals Effect of different sources of alumina on the microstructure and mechanical properties of the triaxial porcelain

Cerâmica ◽  
2014 ◽  
Vol 60 (356) ◽  
pp. 471-481 ◽  
Author(s):  
G. Gralik ◽  
A. L. Chinelattot ◽  
A. S. A. Chinelatto
Keyword(s):  
Mechanical Properties ◽  
Aluminum Hydroxide ◽  
Raw Materials ◽  
Primary Aluminum ◽  
Mechanical Resistance ◽  
Alternative Source ◽  
X Ray ◽  
Alternative Materials ◽  
Alumina Refractory ◽  
Different Sources

Porcelains composed of kaolin-quartz-feldspar are called triaxial porcelains. The use of alumina as a substitute for quartz in porcelains has been developed for some time. The results show a significant improvement in their mechanical properties, but alumina has a high cost. The possibility of using alternative materials as a source of alumina with lower cost was investigated. In this work, alternative raw materials were used as a source of alumina: refractory bauxite, primary aluminum hydroxide, reprecipitated aluminum hydroxide. Compositions with commercial alumina and quartz were also formulated to better understand the effects of adding these alternative materials. The raw materials were milled, dried, and characterized by analysis of the particle size distribution, X-ray diffraction, and X-ray fluorescence. The compositions were formulated by replacing the different sources of alumina in the formulation of porcelain. The compositions studied were shaped by pressing and sintered at different temperatures (1150-1400 ºC). The results showed that the use of bauxite and aluminum hydroxide as an alternative source of Al2O3 is viable. The impurities contained in refractory bauxite contributed to the lower values of flexural strength found in compositions having refractory bauxite as a source of alumina. The compositions with reprecipitated aluminum hydroxide showed a high mechanical resistance at low sintering temperatures, while compositions with aluminum hydroxide obtained by the Bayer process achieved good results of mechanical strength in a wide temperature range.

Papers as Functional Green Materials

2013 ◽  
Vol 747 ◽  
pp. 715-718 ◽  
Author(s):  
Jean Francis Bloch ◽  
Imtiaz Ali ◽  
Raphael Passas ◽  
Sabine Rolland du Roscoat
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Fluid Transport ◽  
Natural Fibers ◽  
Mechanical Resistance ◽  
X Ray ◽  
Fibrous Network ◽  
Green Materials ◽  
Micro Tomography ◽  
Recycled Fibers

Paper is constituted of natural fibers and represents a perfect example of structural multifunctional materials. Indeed, its fibrous structure is engineered to fit the different end use properties: both optical and mechanical properties are usually required. These requirements may lead to contradictory needs in terms of structure. The influence of the structure on the physical properties is classically tackled based on standard methods such as the estimation of the porosity. However, this macroscopic property is not sufficient in terms of optimization of the fibrous network. For example, fluid transport has to be controlled either in the bulk of the material or only at its surface in the case of health or printing applications. Consequently, the characterization at the macro-level of the structure has to be complemented with an experimental measurement at the fiber level. The X-ray synchrotron micro-tomography, an imaging technique, is based on X-ray transmission. It allows the structure to be analyzed in 3D. It was carried in a large instrument (ESRF, France). The characterization of samples containing different recycled fibers was carried out. In particular, the influence of the number of cycles of drying-pulping is studied. Both qualitative and quantitative characterizations are obtained. The use of recycled fibers may also be included in the elaboration of materials, taking into account the modification of the fibers in terms of morphology and mechanical properties, essentially flexibility. Mechanical properties (tensile and deformation) constitute the main examples of the analysis showing the effect of the recycling of natural fibers: the decrease in mechanical resistance of the fibrous network is explained in terms of the increase of the global porosity, essentially in the bulk of the materials. The profile of porosity in the thickness direction is found to be essential to understand the evolution of physical properties.

scholarly journals Preparation of Xylan-g-/P(AA-co-AM)/GO Nanocomposite Hydrogel and its Adsorption for Heavy Metal Ions

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 621 ◽  
Author(s):  
Weiqing Kong ◽  
Minmin Chang ◽  
Chunhui Zhang ◽  
Xinxin Liu ◽  
Bei He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Adsorption Capacity ◽  
Heavy Metal Ions ◽  
Raw Materials ◽  
Ammonium Persulfate ◽  
Maximum Adsorption Capacity ◽  
Nanocomposite Hydrogel ◽  
X Ray ◽  
Nanocomposite Hydrogels

Xylan-g-/P(AA-co-AM)/Graphene oxide (GO) hydrogels were prepared and used in the removal of heavy mental ions. Acrylamide (AM), acrylic acid (AA), and xylan were used as the raw materials to prepare the hydrogels with ammonium persulfate (APS) as the initiator. The prepared hydrogels were characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and energy dispersive X-ray (EDX). Some important properties of nanocomposite hydrogels such as swelling behavior, mechanical property, and adsorption capacity were also examined as well as the regeneration of the hydrogels. The results showed that the prepared hydrogels reached the equilibrium state of swelling after 12 h, and the compressive strength of the hydrogel with 30 mg of GO could reach up to 203 kPa. Compared with traditional hydrogel, the mechanical properties of the hydrogels with GO were obviously improved. The maximum adsorption capacity of hydrogels for Pb2+, Cd2+, and Zn2+ could reach up to 683 mg/g, 281 mg/g, and 135 mg/g, respectively. After five cycles of adsorption and desorption, the recovery rate of the hydrogels on Pb2+, Cd2+, and Zn2+ was still up to 87%, 80%, and 80%, respectively—all above 80%.

Conversion of Bacterial Cellulose to Cellulose Nitrate with High Nitrogen Content as Propellant Ingredient

2021 ◽  
Vol 317 ◽  
pp. 305-311
Author(s):  
Siti Hasnawati Jamal ◽  
Nursyafiqah Jori Roslan ◽  
Noor Aisyah Ahmad Shah ◽  
Siti Aminah Mohd Noor ◽  
Ong Keat Khim ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Bacterial Cellulose ◽  
Raw Materials ◽  
Cellulose Nitrate ◽  
High Nitrogen Content ◽  
X Ray Diffraction ◽  
Surface Electron ◽  
X Ray ◽  
Wide Range ◽  
Different Sources

Cellulose nitrate has attracted great interest amongst researchers due to its uses in wide range of products including paint and gun propellant. Therefore, this work focuses on the synthesis of cellulose nitrate from two different sources of cellulose; plant and bacterial, in order to obtain high percentage of nitrogen content hence suitable for propellant application. The synthesis of cellulose nitrate was carried out via nitration method using nata de coco and kapok (Ceiba pentadra L) as a raw materials of cellulose. The samples were then characterized by elemental analysis, fourier transform infrared (FTIR) spectroscopy, x-ray diffraction and surface electron morphology (SEM). FTIR analysis showed the presence of NO2 groups in both nitrocellulose proving that nitrocellulose was successfully synthesized by nitration method even though it was produced from different sources of cellulose. It is also showed nitrocellulose with high percentage of nitrogen content was obtained from bacterial cellulose, 12.69% rather than plant cellulose.

Preparation of α-Al2O3 Powder by Microwave Pyrolysis

2014 ◽  
Vol 602-603 ◽  
pp. 88-92 ◽  
Author(s):  
Hao Chen ◽  
Bing Bing Fan ◽  
Xin Zhang ◽  
Xiao Xuan Pian ◽  
Rui Zhang
Keyword(s):  
Aluminum Hydroxide ◽  
High Purity ◽  
Raw Materials ◽  
Xrd Analysis ◽  
Fast Method ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
Microwave Pyrolysis ◽  
X Ray ◽  
Thermal Analyzer

A fast method of microwave pyrolysis was provided to prepare α-Al2O3 powders. Aluminum hydroxide and Aluminum ammonium sulfate doclecahydrate were used as raw materials to obtain α-aluminum oxide powder by microwave pyrolysis, respectively. Thermo-Gravimetric/Differential Thermal Analyzer (TG/DTA) and X-ray Diffraction (XRD) analysis were employed to investigate pyrolysis process and the transformation of metastables Al2O3 in the process of heating different precursors. Meanwhile, Flied Emission Scanning Electron Microscopy (FESEM) was applied to observe microstructure and grain growth, and the phase composition was characterized by XRD. The results indicated that the high purity α-Al2O3 was obtained which met the demands of market, and the sample obtained from aluminum hydroxide performed high purity, small particle size and, while the sample from ammonium aluminum sulfate showed lower purity and larger grain size.

scholarly journals Development and Properties of New Mullite Based Refractory Grog

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 779
Author(s):  
David Zemánek ◽  
Karel Lang ◽  
Lukáš Tvrdík ◽  
Dalibor Všianský ◽  
Lenka Nevřivová ◽  
...  
Keyword(s):  
Raw Materials ◽  
High Alumina ◽  
Firing Process ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Microscopies ◽  
Alumina Refractory ◽  
Refractory Aggregate

The presented study is focused on optimization and characterization of a high-alumina refractory aggregate based on natural raw materials—kaolins, claystone, and mullite dust by-product (used to increase the alumina and mullite contents, respectively). In total, four individual formulas with the Al2O3 contents between 45 and 50 wt.% were designed; the samples were subsequently fired, both in a laboratory oven and an industrial tunnel furnace. The effects of repeated firing were examined during industrial pilot tests. Mineral and chemical compositions and microstructures, of both the raw materials and designed aggregates, were thoroughly investigated by the means of X-ray fluorescence spectroscopy, powder X-ray diffraction, and optical and scanning electron microscopies. Porosity, mineral composition, and mullite crystal-size development during the firing process were also studied. Based on the acquired results, the formula with the perspective to be used as a new mullite grog, featuring similar properties as the available commercial products, however, with reduced production expenses, was selected. The quality of grog determines to a large extent the properties of the final product. Hence, optimization of aggregates for specific refractories is of a great importance. The production of engineered aggregates provides the opportunity to utilize industrial by-products.

Mechanical Properties of Bioactive Glass Fabricated Using Natural Resources Materials

2020 ◽  
Vol 1010 ◽  
pp. 620-625
Author(s):  
Ahmad Kamil Fakhruddin ◽  
Hasmaliza M. Mohamad
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Natural Resources ◽  
Bioactive Glass ◽  
Rice Husk Ash ◽  
Raw Materials ◽  
Control Sample ◽  
Glass Frit ◽  
X Ray Diffraction ◽  
X Ray

Bioactive glass use silica (SiO2), calcium carbonate (CaCO3), sodium carbonate (Na2CO3), phosphorus pentoxide (P2O5) as raw materials. In this work, bioactive glass (BG); 45S5 bioactive glass was synthesized using natural resources materials; rice husk ash (RHA) as silica (SiO2) source and seashell (SS) as calcium carbonate (CaCO3) source through melt derived method. All raw materials were melted at 1400 °C and water quenched. The glass frit obtained was milled and sieved then analyzed using X-ray diffraction (XRD), Fourier Transform Infrared spectroscope (FTIR) and Scanning Electron Microscope (SEM). The mechanical properties 45S5 BG pellet was observed through diametral tensile stress (DTS). The XRD and FTIR pattern for all sample synthesized using natural resources raw materials show similar pattern with control sample 45S5 synthesis using pure raw materials. The mechanical properties for all samples also have not significantly different with control samples

Soil-Lime Blocks Using Construction Residues - Durability Study

2012 ◽  
Vol 727-728 ◽  
pp. 1422-1427
Author(s):  
Suélen Silva Figueiredo ◽  
Cibelle Guimarães Silva ◽  
Izabelle Marie Trindade Bezerra ◽  
Suellen Lisboa Dias ◽  
Gelmires Araújo Neves ◽  
...  
Keyword(s):  
Construction Industry ◽  
Raw Materials ◽  
Raw Material ◽  
Partial Replacement ◽  
Distribution Analysis ◽  
X Ray Diffraction ◽  
New Techniques ◽  
X Ray ◽  
Curing Period ◽  
Alternative Materials

The construction industry in addition to being considered one of the biggest natural resources consumers is still responsible for generating large quantities of residues. The impacts caused by these residues have motivated research aimed at developing new techniques for reuse and recycling this material by using as raw material to make alternative materials. The introduction of demolition residues (DR) in soil-lime bricks replacing part of the pozzolan becomes possible due to the cementing properties that these residues may present when finely grounded. This study aims to evaluate the durability of soil-lime blocks embedded with demolition residues. For this study the raw materials were characterized by particle size distribution analysis, X-ray diffraction and chemical analysis. Then test specimens were prepared using mixes in a 1:10 ratio of lime:soil and embedded with residue in partial replacement of lime, in the proportions of 25%, 50% and 75% with curing period of 90 days. Later, the test specimens were evaluated for durability. The results showed that soil-lime bricks embedded with contents above 50% of residues had their durability affected.

scholarly journals Influence of Local Mineral Raw Materials On The Commercial Success of Aveiro Production of Ancient Ceramic Sugar Jars

2021 ◽  
Author(s):  
Rocha Fernando ◽  
Paulo Morgado
Keyword(s):  
Upper Cretaceous ◽  
Raw Materials ◽  
Production Cycle ◽  
Mechanical Resistance ◽  
Sugar Production ◽  
Local Production ◽  
Mineralogical Analysis ◽  
X Ray ◽  
Ancient Ceramic ◽  
Production Areas

Abstract Sugar forms were conic ceramic jars having a hole at the bottom, being used specifically for the stage of the purge of the sugar cake. These pieces played a paramount role in sugar production cycle, being used for the maturation of the sugar, and since the 15th until the beginning of the 19th centuries, the old pottery centres from Aveiro and Lisbon regions, produced heavily these “formas de açúcar” (“sugar jars”) which were exported to sugar production areas, at places as diverse as Madeira, Canaries, Cape Verde, Cuba and Brazil. Mineralogical analysis by x-ray powder diffraction was carried out on bulk samples. Chemical composition was assessed by X-Ray fluorescence. The obtained results gave important information about the composition of the studied materials, and also about their raw materials. Mineralogical and chemical data obtained in samples from Aveiro point to a local production, using the upper Cretaceous (Maastrichian) marly (dolomitic) clays and clayey sands as main raw materials. Ceramics from Barreiro (Lisbon) are in general more silicated and less carbonated, composition close to the Tagus Cenozoic Basin clays. The higher iron content of Aveiro clays favours the glazing of ceramic paste at lower temperatures, giving better mechanical resistance which can justify "their best quality", as referred to in ancient documents.

scholarly journals Study of the effect of diatomite on physico-mechanical properties of concrete

Cerâmica ◽  
2020 ◽  
Vol 66 (377) ◽  
pp. 50-55
Author(s):  
A. R. S. Macedo ◽  
A. S. Silva ◽  
D. S. da Luz ◽  
R. L. S. Ferreira ◽  
C. S. Lourenço ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Silica Content ◽  
Mass Concrete ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Specific Mass ◽  
X Ray ◽  
Alternative Materials ◽  
Fine Particle Size

Abstract Concretes present great potential to be used in many areas of civil construction. Their properties can be improved by substitution or addition of alternative materials to the Portland cement. The diatomite is a sedimentary material composed mainly by silica and amorphous impurities, presenting very fine particle size, high porosity, and low specific mass. Concrete was produced in a ratio of 1:1:2 (cement: sand: gravel) with the addition of diatomite at contents of 5% and 10% by cement weight and a water/cement ratio of 0.54. The physico-mechanical properties of the concretes were evaluated by tests of compressive strength and water absorption by immersion. Also, X-ray diffraction and scanning electron microscopy were carried out to analyze the main phases in the cement paste. The results indicated that the addition of diatomite in the concrete increased the compressive strength due to the silica content in the material and reduced slightly the porosity.

Effects of the Addition Amount of Silica Aerogels on Mechanical Properties and Microstructure of Insulating Materials

2011 ◽  
Vol 374-377 ◽  
pp. 803-806
Author(s):  
Lin Ma ◽  
Jia Bin Wang ◽  
Gui Yan Xin ◽  
Qi Yao She
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Water Glass ◽  
Raw Materials ◽  
Silica Aerogels ◽  
X Ray Diffraction ◽  
Insulating Materials ◽  
X Ray ◽  
Addition Amount ◽  
Scanning Electron

Insulating materials were prepared by microsilica, silica aerogels and quartz fibers as raw materials, water glass as binder, and molded by the semi-dry method. In this paper, the effects of the addtion amount of silica aerogels on mechanical properties and microstructure of insulating materials were studied. X-ray diffraction (XRD) was used to characterize the phase composition and scanning electron microscope (SEM) was used to characterize the microstructure of the materials. The results show that when the silica aerogels content was at 40%, the material had the best properties in present study of true porosity of 45.9%, flexural strength of 5.0MPa and compressive strength of 37.9MPa, respectively.

Sign in / Sign up

Export Citation Format

Share Document