Preparation of Bauxite-Based Homogenized Mullite Grogs with Bauxite and Coal Gangue

2011 ◽  
Vol 199-200 ◽  
pp. 1940-1944 ◽  
Author(s):  
Zhong Zheng Yang ◽  
Zhen Xian Xing ◽  
Zhan Fang Gai ◽  
Huan Qiang Liu

The sintering behavior, physical properties and heat processing changes of bauxite-based homogenized grogs prepared by homogenization process and high temperature sintering using bauxite as starting material were investigated. Results show that the bauxite-based mullite can be synthesized by the method, sintering temperature with and without MgO/CeO2sintering aids are 1600°C and 1700°C separately, the mullite with apparent porosity of<1.0% and 2.5%, bulk density of ≥2.87g•cm-3and 2.75g•cm-3, Refracteriness-Under-Load(RUL) 1600°C and 1620С; changes in the heat processing is divided into three stages: dehydration stage(400°С~900°С ), primary mullitization stage(1000°С ~1200°С) and secondary mullitization stage(>1200°С).

2011 ◽  
Vol 399-401 ◽  
pp. 834-837
Author(s):  
Chun Hui Cao ◽  
Jun Cong Wei ◽  
Jian Kun Huang ◽  
Jun Bo Tu

MgAl2O4-SiC composites were prepared by using MgAl2O4 and SiC powder as main starting materials, being pressed to cylindrical specimens of Φ30mm×30mm at 200 MPa and heated respectively at 1400°C and 1500°C for 3 hours in air atmosphere. The room temperature physical properties of sintered samples were tested according to related national standards. The phase compositions were analyzed by XRD. The microstructure of the fracture of the samples was observed by SEM. The results showed that MgAl2O4-SiC materials could sintered well in air atmosphere. The mechanism is that SiC was oxidized to form active SiO2, which reacted with MgAl2O4 to produce liquid cordierite promoting the sintering of the materials. The sinterability of MgAl2O4-SiC materials was overall improved with increasing the sintering temperature. When the content of SiC of MgAl2O4-SiC materials was 10%, the cold crushing strength and bulk density of the samples reached maximums and apparent porosity reached a minimum; the content of SiC was more than 10%, the sinterability of samples deteriorated.


2019 ◽  
Vol 805 ◽  
pp. 65-70
Author(s):  
Suchittra Inthong ◽  
Denis Russell Sweatman ◽  
Sukum Eitssayeam ◽  
Tawee Tunkasiri

This research is concerned with the effect of sintering temperature on physical and mechanical properties. This Hydroxyapatite-calcium titanate (HA-CT) composites were synthesized using conventional route technique. The HA-CT composites were sintered between 1200 up to 1300 °C. The effect of sintering temperature on the physical and mechanical properties of HA-CT composites was discussed. The physical properties were studied in term of densification and apparent porosity. As well as, the mechanical properties were determined in term of Vickers microhardness. The increasing of the sintering temperature increased both of the bulk density and the Vickers microhardness properties. However, the apparent porosity was decreased with increasing sintering temperature. The highest bulk density was found at 0.15 mol.% of CT in HA-CT composites which was sintered at 1300 °C for 3 h. Moreover, the mechanical properties as a function of the sintering temperature and the CT contents were also discussed and compared with other related work.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Juntong Huang ◽  
Zhaohui Huang ◽  
Shaowei Zhang ◽  
Minghao Fang ◽  
Yan’gai Liu

Si3N4-SiCpcomposites reinforced byin situcatalytic formed nanofibers were prepared at a relatively low sintering temperature. The effects of catalyst Co on the phase compositions, microstructures, and physicochemical-mechanical properties of samples sintered at 1350°C–1450°C were investigated. The results showed that the catalyst Co enhanced the nitridation of Si. With the increase of Co addition (from 0 wt% to 2.0 wt.%), the apparent porosity of as-prepared refractories was initially decreased and subsequently increased, while the bulk density and the bending strength exhibited an opposite trend. TheSi3N4-SiCpcomposites sintered at 1400°C had the highest strength of 60.2 MPa when the Co content was 0.5 wt.%. The catalyst Co facilitated the sintering ofSi3N4-SiCpcomposites as well as the formation of Si3N4nanofibers which exhibited network connection and could improve their strength.


2013 ◽  
Vol 315 ◽  
pp. 349-353 ◽  
Author(s):  
Norhayati Ahmad ◽  
Nurhanna Binti Mohd Zaidan

Sayong ball clay membrane can be fabricated as a cheap membrane material and available commonly at Malaysia. This work was concerned with the study of Sayong ball clay membrane as a water filtration by gel casting technique. Gel casting involves mixing process of Sayong ball clay with the solvent, monomer, dispersant, initiator and catalyst in a certain composition. Tubular membrane was fabricated by controlling the sintering temperature (1000, 1100, 1200, 1300°C). The physical measurements (shrinkage, apparent porosity, and bulk density), microstructure analysis, filtration process (flow rate) and water quality assessments (pH, color, Chemical Oxygen Demand (COD), solid suspended (SS)) were carried out at different sintering temperature. Apparent porosity and bulk density of the samples were measured by using Archimedes method. The effect of sintering temperature on microstructure of the membranes has been investigated using SEM. The experimental results showed that the shrinkage and bulk density increase with increasing sintering temperature. It gives the improvement in water quality with the lowest SS (192 mg/L), lowest COD (4 mg/L) and most colorless (1.1 Gardner units) filtered wastewater as compared to others.


2020 ◽  
Author(s):  
Jianquan Qi ◽  
Yan Li ◽  
Mengyin Li ◽  
Jiahui Xie ◽  
Tianchi Yu ◽  
...  

Abstract The powders of the Ba0.75Sr0.25TiO3 (BST) nanoparticles were directly synthesized by milling of Ba(OH)2·8H2O, Sr(OH)2·8H2O and Ti(BuO)4 in ethanol at room temperature. They have homogenous grains of ~15 nm and the high sintering activity. The dense ceramics with the density >90% can be obtained at a sintering temperature of ≤950 oC by them with adding 3 wt% sintering aids of Bi2O3 and Li2CO3. The sintering behavior of the BST nanoparticles by adding the aids of Bi2O3 and Li2CO3 is studied carefully. Several Bi-related compounds are involved in the sintering procedure at a different temperature. They enhance the mass transfer and promote the sintering densification. These compounds such as Ba2BiO4 and SrBiO4 appear at 800 oC, LiBa4Bi3O11 and Sr1.2Bi0.8O3 appear over 830 oC, and Bi8.11Ba0.89O13.05 appears at 950 oC. The cation Bi in the ceramics has mixture valences of 3+ and 5+. It makes the ceramics as semiconducting state with the dark gray color and decreases the ceramics resistivities. With the sintering temperature increase, especially at 950 oC, the cation Bi tends back to single valence of +3 in the ceramics. The most of alkaline earth cations in Bi-related compounds will release and resorb into the lattice of BST and drive the densification of the nanoparticles. The BST ceramics can have a peak dielectric constant >6500 at 53 oC, loss <0.025, and resistivity >1012 W·cm when sintered at a temperature of ≥900 oC with 3 wt% sintering aids. They have a potential application for multiple layer ceramic capacitors (MLCC) with silver inner-electrodes.


2020 ◽  
Vol 55 (1) ◽  
pp. 43-52 ◽  
Author(s):  
NB Bohara ◽  
DB Ghale ◽  
YP Chapagain ◽  
N Duwal ◽  
J Bhattarai

Effect of firing temperature on some physico-mechanical properties of ten brick samples, those were composed by feldspars, quartz, alumina-rich spinel, primary mullite and hematite phases, was investigated in accordance with ASTM standards. The brick samples fired between 700° to 1100° C showed 11-23 % water adsorptivity (WA), 19-37 % apparent porosity (AP) and 1.50-1.65 g/cm3 bulk density (BD) indicate good physical properties. The maximum compressive strength (CS) of the fired-bricks at 950° to 1000° C was found to be between 15.6 and 17.1 MPa. At 700°-1000° C firing temperatures, the CS of these bricks is found to be increased exponentially with decreasing of both WA and AP, however it is found to be increased with increasing the BD. Consequently, it can be said that there is good correlation between mechanical and physical properties of the fired-brick samples up to the firing temperature of 1000° C. Bangladesh J. Sci. Ind. Res.55(1), 43-52, 2020


2007 ◽  
Vol 336-338 ◽  
pp. 1062-1064 ◽  
Author(s):  
Fa Qiang Yan ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang

In this study, spark plasma sintering (SPS) was applied to prepare α-Si3N4 ceramics of different densities with magnesia, silicon dioxide, alumina as the sintering aids. The sintering behavior and liquid phase sintering (LPS) mechanism were discussed and the factors influencing the density of the prepared samples were analyzed. Microstructures of sintered samples were observed and the phase compositions were analyzed. The results showed that α-Si3N4 ceramics can be sintered by SPS based on the reaction among α-Si3N4 and sintering additives which lead to the liquid phase and the density can be well controlled from 2.48 to 3.09 g/cm3 while the content of the sintering aids changes from 10% to 28.5% and sintering temperature from 1400°C to 1500°C.


2013 ◽  
Vol 849 ◽  
pp. 3-7
Author(s):  
Song Chen ◽  
De Gui Zhu

In this work, the energy-saving LTCC composite ceramics containing quartz, fused quartz and zirconia ceramic particles, respectively based on the binary system BaO-B2O3 were prepared by traditional solid-state preparation process at a sintering temperature of 900°C. Sintering mechanism and physical properties of the LTCC composite ceramics are investigated and discussed in detail in terms of their mineral phase composition. The results indicate that the introduction of α-alumina to the binary system BaO-B2O3 can improve the sintering behavior whereas the presence of the functional ceramic particles in the composite ceramics is important to achieve the peculiar physical characterlistics, which consequently supply more possibilities to regulate on the physical properties of the composite ceramics.


Alloy Digest ◽  
1989 ◽  
Vol 38 (7) ◽  

Abstract CALCARB is a rigid, high-temperature composite made from discontinuous lengths of carbon fibers, vacuum formed and bonded by a carbonized resin. It is a relatively strong, high-purity carbon material with low bulk density that is readily machinable. This datasheet provides information on composition, physical properties, and compressive strength. It also includes information on high temperature performance and corrosion resistance as well as machining and surface treatment. Filing Code: Cp-1. Producer or source: Calcarb Inc..


2016 ◽  
Vol 697 ◽  
pp. 591-594
Author(s):  
Shao Hua Wang ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu ◽  
Wen Jie Yuan

The in situ nitrides bonded MgAl2O4-C refractories were prepared by using high quality fused spinel (MgAl2O4≥ 97%), natural flake graphite (C ≥ 96%) and silicon powder (Si ≥ 98%) as raw materials and the liquid calcium lignosulfonate with a concentration of 1.25 g/ml was used as binder (4 wt%). The effect of sintering temperatures on physical properties and phase compositions were investigated. The results show that β-sialon and α-Si3N4were formed in the samples sintered at 1400°C, 1450°C and 1500°C, and AlON and AlN were formed in the samples sintered at 1550°C. The sample that sintered at 1450°C exhibits the best bulk density and apparent porosity of 2.84 g/cm3 and 14.73%, respectively, and the highest compressive strength


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