Effect of Calcined-Bauxite Quality and Secondary Mullitization Reaction on Firing and Properties of Ceramic Plates

2019 ◽  
Vol 960 ◽  
pp. 207-213
Author(s):  
Li Biao Xiao ◽  
Xiao Qing Hua ◽  
Qun Hu Xue

Addition of different types of calcined bauxites to the ceramic plate formulation was performed to study effects on the firing and properties of the resulting ceramic plates. The physical and chemical characteristics, high-temperature reaction degree, thermochemical behavior, mineral composition, and microstructure of the calcined bauxites were analyzed. The results showed that lightly calcined bauxite could minimize the linear shrinkage rate. However, incomplete high-temperature secondary mullitization reaction could inhibit completion of product sintering and result in a loose microstructure, high water absorption index, and low modulus of rupture. Application of GAL-85 high-temperature calcined bauxite yielded a product with good sintering performance and low water absorption; increased amounts of mullite reinforcement phase also increased the strength of the plate. The degree of secondary mullitization was the main factor affecting the performance of the ceramic plate.

Author(s):  
Adegbenle Bukunmi O

Laterite samples from Ede area with particle components of 19.7% clay, 32.8% silt and 47.5% sand was stabilized with combined cement, lime and bitumen and test for Compressive strength, Linear Shrinkage, Permeability and Water Absorption. The stabilizers were mixed with laterite soil in different ratios and percentage. The laterite carried 90% which is constant while the three stabilizers shared the remaining 10% in varying form. After 28 days of curing, laterite stabilizer with 90% of laterite, 8% of cement, 1% lime and 1% bitumen (LCLB1) possessed compressive strength of 2.01N/mm2. It Water Absorption Capacity was 3.05%. LCLB4 stabilizer (90% laterite, 6% cement, 2% lime and 2% bitumen) has the same compressive strength with LCLB1 stabilizer but with a high Water Absorption Capacity of 4.2%. The stabilizer of 90% laterite, 3.33% cement, 3.33% lime and 3.33% of bitumen (LCLB8) has the lowest compressive strength of 0.74N/mm2 and the highest Water Absorption Capacity of 5.39%. The results shows that LCLB1 stabilizer is a better stabilizer for strength and blocks made from laterite stabilized with it stand a good alternative to sand Crete blocks in building constructions. The combination of these stabilizers in order to determine a most economical volume combination for optimum performance is highly possible and economical.


2015 ◽  
Vol 820 ◽  
pp. 449-454
Author(s):  
Alline Sardinha Cordeiro Morais ◽  
Thais Mardegan Louzada ◽  
Veronica Scarpini Candido ◽  
Sergio Neves Monteiro ◽  
Carlos Mauricio Fontes Vieira

The incorporation of industrial wastes into clayey ceramics used in civil construction is becoming a worldwide procedure not only to provide an environmentally correct destination for the waste but, in some cases, to improve the ceramic properties. The objective of the present work was to evaluate the effect of incorporation of a glass powder waste from decontamination process of fluorescent lamps into clayey ceramics. This evaluation was performed based on the technological properties of water absorption, linear shrinkage ad flexural strength. The properties evaluation was complemented by optical microscopy structural observation. The glass waste was incorporated in up to 30 wt% and specimens were uniaxially pressed at 20 MPa and fired at a relatively higher temperature of 1000°C. The results confirmed a substantial improvement of both the water absorption and the strength with glass waste incorporation into clayey ceramics.


2014 ◽  
Vol 775-776 ◽  
pp. 69-74 ◽  
Author(s):  
Monica Castoldi Borlini Gadioli ◽  
Mariane Costalonga de Aguiar ◽  
Carlos Maurício Fontes Vieira ◽  
Verônica Scarpini Candido ◽  
Sérgio Neves Monteiro

Brazil is currently one of the world leading producers and exporters of ornamental stones. The increasing production also generates a proportionally huge amount of wastes. Depending on stones such as granite, these wastes may be composed of relatively high content of alkaline oxides. This is a low melting point flux with advantage for a potential addition of the waste into common clay ceramic. Thus, the present work investigated the addition of a granite waste, generated during the sawing stage using the multi-wire technology, into clayey ceramics fired at 1200oC. This ceramic added with up to 30 wt% waste were evaluated in terms of linear shrinkage, water absorption and flexural strength. It was found that the waste fluxing compounds promoted a reduction in water absorption and increase in strength that are associated with an improved clayey ceramic.


2018 ◽  
Vol 15 (1) ◽  
pp. 59-69
Author(s):  
K.G. Akpomie ◽  
C.C. Ezeofor ◽  
O.L. Alum ◽  
U.A. Augustine ◽  
F.N. Ibeanu

The effect of Dioscorea rotundata peel environmental waste as an insulating additive for local clay was studied. The potential of a low cost indigenous clay mineral obtained from Akpugu-Ezedike in Nigeria for industrial application was also evaluated. The clay was characterized by the Fourier transform infrared spectroscopy, X-ray diffraction and Scanning electron microscopy (SEM). Prepared slurry mixture of the clay and peels were shaped, dried and fired. The chemical composition of the clay was determined by classical methods. Physical properties such as linear shrinkage, total shrinkage, modulus of rupture, apparent density, bulk density, apparent porosity,s welling index and water absorption, modulus of plasticity and refractoriness of the fired samples were determined. The clay was found to have a refractoriness of 12000C. SEM analysis revealed an increase in porosity of the fired clay bodies with increase in dosage of Dioscorea rotundata added. This result was corroborated by the high apparent porosity 49.67 – 60.02% and water absorption recorded 30.92 – 48.44% for the mixed fired samples. The result of this study clearly indicated the potential of Dioscorea rotundata peel as additive in enhancing insulating properties of fired clay as well as the usefulness of the local clay mineral for industrial purposes.


1970 ◽  
Vol 45 (4) ◽  
pp. 387-392 ◽  
Author(s):  
Shahnaj Parveen ◽  
Shirin Akter Jahan

The cost of producing sanitary ware in Bangladesh is substantially low as compared to the advanced countries, because of low labour cost and abundance of basic raw materials. Ten sanitary ware compositions were prepared using Bijoypur clay, black clay, red clay, ball clay and china clay with fluxes and filler materials. Chemical compositions of the raw materials and the formulated batch compositions were determined. Physical properties (linear shrinkage, bulk density, apparent porosity, water absorption etc) and the modulus of rupture (MOR) of the prepared body compositions were also determined. The sample specimens were fired at 1150°C and 1200°C. Compositions S-3, S-4, S- 5, S-7, S-8 and S-10 at 1150°C were found to be of good quality. Key words: Linear shrinkage; Bulk density; Water absorption; MOR; Red clay; Black clay. DOI: 10.3329/bjsir.v45i4.7386 Bangladesh J. Sci. Ind. Res. 45(4), 387-392, 2010


Clay Minerals ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 165-175 ◽  
Author(s):  
M. Medhioub ◽  
W. Hajjaji ◽  
M. Hachani ◽  
A. Lopez-Galindo ◽  
F. Rocha ◽  
...  

AbstractThis study aims to find alternatives to some overexploited deposits in the north of Tunisia. The clays of the Sidi Khalif formation, of Uppermost Jurassic to Lower Cretaceous age, seem suitable to support this strategy, due to their abundance. In terms of mineralogy, they can be divided into two distinct groups, related to their palaeogeographic and eustatic contexts. The clays of the Sidi Khalif formation from Jebel Houareb (JH) and Jebel Meloussi (JM) are richer in clay minerals, while those of Jebel Rhouis (JR) and Jebel Boudinar (JB) zones are dolomite-rich. The compositional differences between the two groups influenced their technological behaviour in production of ceramic tiles. Upon firing, forsterite and gehlenite crystallized in the carbonate-rich JR and JB clays, whereas mullite formed in the JH and JM clays. Concerning their ceramic properties, the tiles made from JR or JB clays showed low bending strength and high water absorption. For JH and JM, the tiles had slightly greater mechanical resistance, but exhibited considerable linear shrinkage. These defects were partially corrected by introducing new formulations based on the same clays and by altering the firing cycles (HM1, HM2, RB1 and RB2). With these modifications, “Porcelanico” and “Monoporosa” technologically conforming tiles were obtained from HM2 and RB2 formulations, respectively.


2020 ◽  
Vol 10 (10) ◽  
pp. 59-67
Author(s):  
Victor N. ANTIPOV ◽  
◽  
Andrey D. GROZOV ◽  
Anna V. IVANOVA ◽  
◽  
...  

The overall dimensions and mass of wind power units with capacities larger than 10 MW can be improved and their cost can be decreased by developing and constructing superconducting synchronous generators. The article analyzes foreign conceptual designs of superconducting synchronous generators based on different principles: with the use of high- and low-temperature superconductivity, fully superconducting or only with a superconducting excitation system, and with the use of different materials (MgB2, Bi2223, YBCO). A high cost of superconducting materials is the main factor impeding commercial application of superconducting generators. In view of the state of the art in the technology for manufacturing superconductors and their cost, a conclusion is drawn, according to which a synchronous gearless superconducting wind generator with a capacity of 10 MW with the field winding made of a high-temperature superconducting material (MgB2, Bi-2223 or YBCO) with the «ferromagnetic stator — ferromagnetic rotor» topology, with the stator diameter equal to 7—9 m, and with the number of poles equal to 32—40 has prospects for its practical use in the nearest future.


2021 ◽  
Vol 11 (10) ◽  
pp. 4635
Author(s):  
Marcel Ulrich Ahrens ◽  
Maximilian Loth ◽  
Ignat Tolstorebrov ◽  
Armin Hafner ◽  
Stephan Kabelac ◽  
...  

Decarbonization of the industrial sector is one of the most important keys to reducing global warming. Energy demands and associated emissions in the industrial sector are continuously increasing. The utilization of high temperature heat pumps (HTHPs) operating with natural fluids presents an environmentally friendly solution with great potential to increase energy efficiency and reduce emissions in industrial processes. Ammonia-water absorption–compression heat pumps (ACHPs) combine the technologies of an absorption and vapor compression heat pump using a zeotropic mixture of ammonia and water as working fluid. The given characteristics, such as the ability to achieve high sink temperatures with comparably large temperature lifts and high coefficient of performance (COP) make the ACHP interesting for utilization in various industrial high temperature applications. This work reviews the state of technology and identifies existing challenges based on conducted experimental investigations. In this context, 23 references with capacities ranging from 1.4 kW to 4500 kW are evaluated, achieving sink outlet temperatures from 45 °C to 115 °C and COPs from 1.4 to 11.3. Existing challenges are identified for the compressor concerning discharge temperature and lubrication, for the absorber and desorber design for operation and liquid–vapor mixing and distribution and the choice of solution pump. Recent developments and promising solutions are then highlighted and presented in a comprehensive overview. Finally, future trends for further studies are discussed. The purpose of this study is to serve as a starting point for further research by connecting theoretical approaches, possible solutions and experimental results as a resource for further developments of ammonia-water ACHP systems at high temperature operation.


Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1204
Author(s):  
Mengna Chen ◽  
Xuelong Chen ◽  
Caiyan Zhang ◽  
Baozheng Cui ◽  
Zewen Li ◽  
...  

One type of low-cost and eco-friendly organic‒inorganic superabsorbent composite (SAPC) was synthesized by free radical polymerization of acrylic acid (AA), starch (ST), sodium alginate (SA) and kaolin (KL) in aqueous solution. The structure and morphology of the SAPC were characterized by Fourier transform infrared spectrometer (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The influence of different reaction conditions on water absorption of SAPC, i.e., SA and KL contents, AA neutralization degree (ND), potassium persulfate (KPS) and N, N′-methylenebisacrylamide (MBA) loading were systematically studied. Under the optimal synthesis conditions, very high water absorption of 1200 g/g was achieved. The swelling kinetic mechanism of SAPC was studied by pseudo-second order swelling kinetics model and Ritger‒Peppas model. The performances of SAPC under different environments were tested and results revealed that this new SAPC had excellent swelling capacity, high water retention, good salt tolerance in monovalent salt solution (NaCl solution) and good pH tolerance between 4 and 10.


Gels ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 5
Author(s):  
Samuel Mandin ◽  
Samuel Moreau ◽  
Malika Talantikite ◽  
Bruno Novalès ◽  
Jean-Eudes Maigret ◽  
...  

Bio-based aerogels containing cellulose nanofibrils (CNFs) are promising materials due to the inherent physical properties of CNF. The high affinity of cellulose to plant hemicelluloses (xyloglucan, xylan, pectin) is also an opportunity to develop biomaterials with new properties. Here, we prepared aerogels from gelled dispersions of CNFs and xyloglucan (XG) at different ratios by using a freeze-casting procedure in unidirectional (UD) and non-directional (ND) manners. As showed by rheology analysis, CNF and CNF/XG dispersions behave as true gels. We investigated the impact of the freezing procedure and the gel’s composition on the microstructure and the water absorption properties. The introduction of XG greatly affects the microstructure of the aerogel from lamellar to cellular morphology. Bio-based aerogels showed high water absorption capacity with shape recovery after compression. The relation between morphology and aerogel compositions is discussed.


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