Synthesis of Mullite Using Low-Grade Bauxite and Coal Gangue

2014 ◽  
Vol 602-603 ◽  
pp. 331-334 ◽  
Author(s):  
Chun Yan Zeng ◽  
Zhao Hui Huang ◽  
Ming Hao Fang ◽  
Yan Gai Liu
Keyword(s):  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Coal Gangue ◽  
Alumina Content ◽  
Low Grade ◽  
Microscopic Morphology ◽  
Industrial Alumina

The total bauxite reserves of China are about 3.7 billion tons, however the principal and the first-class bauxite reserves account for only about 20%. A large number of coal gangue was accumulated on the surface of earth, which not only encroaches land but also pollutes the environment. In this study, low-grade bauxite with alumina content of 53.18 wt.% originating from Shanxi Yangquan and coal gangue with alumina content of 38.07 wt.% originating from Shanxi Datong were used to synthesize mullite materials. Bauxite and gangue were mixed by the ratio of 1 to 1. The ingredients were prepared according to the alumina content of 45.63 wt.% and 70 wt.%, by adding a certain amount of industrial alumina, respectively. The samples were sintered at 1350°C to 1600°C after being milled, dried and formed. The influence of alumina content and sintering temperature on the phase, microscopic morphology and properties of samples were discussed. The results show that, the main phases of the sample with the alumina content of 70 wt.% were mullite (more than 60 %) and corundum after being sintered for 4h at 1600 °C. The phenomenon of columnar mullite and granular corundum staggering had been observed. The bulk density and the bending strength of sample is 3.21 g/cm3and of 220.73 MPa respectively.

scholarly journals Effect of Sintering Temperature on Property of Low-Density Ceramic Proppant Adding Coal Gangue

2019 ◽  
Vol 26 (1) ◽  
pp. 94-98
Author(s):  
Jianying HAO ◽  
Huilan HAO ◽  
Yunfeng GAO ◽  
Xianjun LI ◽  
Mei QIN ◽  
...  
Keyword(s):  
Solid Waste ◽  
Bulk Density ◽  
Apparent Density ◽  
Sintering Temperature ◽  
Coal Gangue ◽  
Low Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sintering Method ◽  
Waste Coal

Calcined flint clay (45.6 wt.% Al2O3) and solid waste coal gangue were used to prepare low-density ceramic proppant by solid state sintering method. The density and breakage ratio of the ceramic proppant were systematically investigated as a function of sintering temperature. The morphology and phase composition of the ceramic proppant were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the ceramic proppant is composed of rod-like mullite and granular cristobalite. Bulk density and apparent density of the proppant first rise and then slightly decrease with increasing the sintering temperature, while breakage ratios under 35 MPa and 52 MPa pressure gradually decrease and then increase. As the sintering temperature increases up to 1400 °C, the ceramic proppant shows denser microstructure. The proppant sintered at 1400 °C have the best performance with 1.27 g/cm3 of bulk density, 2.79 g/cm3 of apparent density, 3.27 % of breakage ratio under 35 MPa closed pressure and 8.36 % of breakage ratio under 52 MPa closed pressure, which conform to the requirement of low-density ceramic proppant. The addition of solid waste can greatly reduce the preparation cost of the ceramic proppant.

scholarly journals Si3N4-SiCpComposites Reinforced byIn SituCo-Catalyzed Generated Si3N4Nanofibers

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Juntong Huang ◽  
Zhaohui Huang ◽  
Shaowei Zhang ◽  
Minghao Fang ◽  
Yan’gai Liu
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Network Connection ◽  
Opposite Trend ◽  
Low Sintering Temperature ◽  
Co Addition

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.

Research of Thermal Shock Resistance of Si3N4 and SiC

2012 ◽  
Vol 549 ◽  
pp. 691-694
Author(s):  
Fang Zhang ◽  
Zhi Liang Huang
Keyword(s):  
Bulk Density ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Silicon Powder ◽  
Nitrogen Atmosphere ◽  
Production Practice ◽  
Shock Resistance ◽  
Powder Content

The study is carried out combing with the production practice in Danjiangkou Hongyuan SiC limited. Si3N4 and SiC were prepared successfully from SiC and Silicon power in nitrogen atmosphere at 1425°C and 1375°C sintering temperature by the serial of techniques, such as ingredients, mixing, molding and drying, respectively. In the actual production, silicon powder content and sintering temperature will directly influence the products of the bending strength and thermal shock resistance. By measuring bending strength, porosities, bulk density, XRD and FESEM, the bending strength and thermal shock resistance of samples were studied mainly by changing sintering temperature and silicon powder content. The results show that bending strength and thermal shock resistance of sample which was added 16% Si powder is best. And bending strength and thermal shock resistance of sample of 1425°C sintering temperature is higher than that of 1375°C sintering temperature.

Sintering Properties of Fused Silica/Nano-Zirconia Composite Ceramic

2013 ◽  
Vol 750-752 ◽  
pp. 81-84
Author(s):  
Yong Wu He ◽  
Jing Long Bu ◽  
Rui Sheng Wang ◽  
Dong Mei Zhao ◽  
Jun Xing Chen ◽  
...  
Keyword(s):  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Composite Ceramic ◽  
High Energy ◽  
Fused Silica ◽  
Raw Material ◽  
Composite Powders ◽  
Wet Chemical Synthesis ◽  
Sintering Properties

Zirconyl chloride was used as zirconium source and fused silica particles were used as main raw material. First of all, the composite powders were prepared by wet chemical synthesis using ammonia as the precipitator and polyethylene glycol as the dispersant. Then, fused silica nanozirconia composite ceramic containing nanometer particle zirconia with different contents (5%, 15%, 25% and 35%) were fabricated in reduction atmosphere at 1300°C, 1350°C and 1400°C for 1 h. The bulk density and bending strength were measured, microstructure was observed by SEM. The result indicated bulk density and bending strength of composite ceramic increase and microstructure becomes denser with content of zirconia increasing. Bulk density of composite ceramic increases and bending strength which reaches maximum at 1350°C firstly increases then decreases with the increase of sintering temperature. Both high sintering temperature and nanozirconia possessing high energy interface can improve the composite ceramic sintering.

Preparation of Calcium Hexaluminate Using Al2O3 and White Beach Sand from Western Australia

2012 ◽  
Vol 512-515 ◽  
pp. 940-944 ◽  
Author(s):  
Chun Yan Zeng ◽  
Zhao Hui Huang ◽  
Jun Tong Huang ◽  
Yan Li ◽  
You Guo Xu ◽  
...  
Keyword(s):  
Western Australia ◽  
High Stability ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Beach Sand ◽  
High Melting ◽  
High Melting Point ◽  
Calcium Hexaluminate ◽  
Calcium Source ◽  
Industrial Alumina

Calcium hexaluminate (CA6) because of its high stability, high melting point and low thermal conductivity properties make it as a new high-temperature insulation materials are valued. In this paper, chemical analysis and XRD were used to investigate the composition of the white beach sand mineral from Perth coast of Western Australia. The main composition of it was carbonate. White beach sand as calcium source respectively, and industrial alumina as aluminum source synthesized CA6 at 1550°C-1650°C for 3h. The results showed that: synthetic CA6 shapes in platelet crystalline. Influence of different amounts of alumina and sintering temperature on synthesis of calcium hexaluminate are studied.The main phase of the samples with different amounts of alumina which decrease or increase 5%, 10% and 15% alumina around theory are CA6. The porosity of the samples obtained is about 53%. The bending strength of Sample S-0 of theoretical ratio values up to 7.73Mpa. Sintering temperature from 1500°C to 1650°C is not conductive to the improvement of apparent porosity of CA6 materials.

Effect of Sintering Aids on the Densification of Andalusite Ceramics

2013 ◽  
Vol 842 ◽  
pp. 78-82
Author(s):  
Jian Feng Wu ◽  
Hao Cheng ◽  
Xiao Hong Xu ◽  
Teng Fei Deng
Keyword(s):  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Potassium Feldspar ◽  
Optimal Composition ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Large Bulk ◽  
Dry Pressing

The ceramics with large bulk density and high bending strength were fabricated via semi-dry pressing and pressureless sintering in the air. Andalusite and calcined bauxite were used as the raw materials, sintering aids such as potassium feldspar, albite, talc, spodumene and borax were added to promote the densification and decrease the sintering temperature of the samples. The best physical properties were obtained on a sample of optimal composition (the addition of sintering aid was talc) sintered at 1500 °C for 3 h, i.e. a bending strength of 138.52 MPa and bulk density of 2.61gcm-3, the sintering temperature was lower than sample without addition of sintering aid.

scholarly journals Utilization of both Electronical Manganese Slag and Silicate Tailings as Raw Materials for Fabrication of Cost-effective Porous Ceramics

2021 ◽  
Author(s):  
Hongfu Lin ◽  
Mengke Li ◽  
Zhiguo He ◽  
Hui Zhong ◽  
Liang Hu ◽  
...  
Keyword(s):  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Cost Effective ◽  
Porous Ceramics ◽  
Waste Utilization ◽  
High Porosity ◽  
Electrolytic Manganese ◽  
Manganese Slag

Abstract Herein, porous wollastonite ceramics with high porosity and low density were successfully fabricated with silicate tailings and electrolytic manganese slag (MS) as primary raw materials. The influences of calcination temperature, SiC and MS addition amounts on porosity, water adsorption, pore distribution, bulk density and bending strength were systematically studied. The results showed that 0.4 wt% of SiC was optimal for the ceramic foaming at the sintering temperature of 1140 ℃. The addition of MS promoted the foaming of ceramic matrix at low temperature. The porosity of ceramics reduced from 78.4–63.7%, bulk density elevated from 0.96 to 1.13 g/cm3, and bending strength increased from 8.43 to 11.22 MPa as the MS increased from 8.33 wt% to 46.67 wt%. Moreover, the best corrosion resistance performance reached to 99.55% with 8.33 wt% MS content and sintering temperature of 1160 ℃. This work is of significance for the solid waste utilization.

Effects of Sintering Temperature on Phases, Microstructures and Properties of Fused Silica Ceramics

2017 ◽  
Vol 726 ◽  
pp. 399-403 ◽  
Author(s):  
Shi Hua Liu ◽  
Peng Chen ◽  
Dan Hua Xu ◽  
Qing Dan Yuan
Keyword(s):  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Fused Silica ◽  
High Density ◽  
Apparent Porosity

Fused silica ceramics, named fused silica articles by means of ceramics fabrication processes, had been widely used in metallurgy, refractory, aviation and many other areas. How to get fused silica ceramics with high density and less cristobalite is on the focus. In this paper, effects of sintering temperature (1150°C, 1200°C, 1250°C, 1300°C, 1350°C) on phases, microstructures and properties of fused silica ceramics were investigated. The results showed that the bulk density of samples increased and the apparent porosity of samples minished gradually, with the increase of sintering temperature. However, the bending strength increased to maximum firstly and then decreased because the emergency of cristobalite at 1300°C. When the sintering temperature was 1250°C, the bulk density, apparent porosity and bending strength was 1.71g·cm-3, 17.6% and 38.87MPa, respectively.

Preparation of Light-Weight Ceramic Microsphere by Dolomite and Gangue

2014 ◽  
Vol 602-603 ◽  
pp. 84-87
Author(s):  
Xiao Wei Cao ◽  
Yan Gai Liu ◽  
Zhao Hui Huang ◽  
Ming Hao Fang ◽  
Rui Long Wen
Keyword(s):  
Bulk Density ◽  
Ball Milling ◽  
Apparent Density ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Coal Gangue ◽  
Light Weight ◽  
Phase Constitution ◽  
Ceramic Microsphere

The ceramic microsphere was prepared by the ball milling and sintering using Dolomite and Coal Gangue as raw materials. The effects of ratio of raw materials, sintering temperature on bulk density and apparent density, phase constitution, microstructure of the ceramic microspheres were studied. The results indicated that the ratio of raw materials, sintering temperature has some effects on the bulk density and apparent density, phase constitution, microstructure of the ceramic microspheres. The bulk density and apparent density of the ceramic microspheres increased with sintering temperature rising. With the increasing of the ratio of dolomite, the bulk density of ceramic microspheres improved firstly and then dropped slightly, the apparent density of ceramic microspheres increased constantly. The bulk densities of the prepared ceramic microspheres were in the range of 0.570 g/cm3to 0.754 g/cm3, the apparent densities of the prepared ceramic microspheres were between 2.419 g/cm3and 2.661 g/cm3.

Fabrication and Properties of Al2O3-SiC/Sialon Composite Refractories

2012 ◽  
Vol 512-515 ◽  
pp. 908-911
Author(s):  
Ding Yun Ye ◽  
Yan Gai Liu ◽  
Zhao Hui Huang ◽  
Ming Hao Fang ◽  
Yang Yang Liu
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Carbothermal Reduction ◽  
Room Temperature ◽  
Bending Strength ◽  
Raw Materials ◽  
Apparent Porosity ◽  
Low Grade ◽  
Sialon Powder ◽  
Aluminate Cement

Sialon powder was synthesized using low grade bauxite as raw materials by carbothermal reduction-nitridation reaction. The influence of synthesizing temperatures (1300°C, 1350°C, 1400°C, 1450°C, 1500°C and 1550°C) on the phases of the final products was studied by XRD technique. β-Sialon (Z=3) formed at 1350°C and decreased when the temperature was higher than 1450°C. The optimizing reaction temperature for preparing Sialon was 1450°C. The Al2O3-SiC/Sialon composite refractories were prepared at 200°C, 400°C and 600°C for 24h with white corundum, brown corundum, SiC, Sialon powders prepared at 1450°C and calcium aluminate cement. The bulk density, apparent porosity, water absorption and bending strength of the Al2O3-SiC/Sialon composite refractories at room temperature were studied. The results show that the bulk density decreased and then increased with the enhancing of the temperature and reached the highest value of 2.43g/cm3 at 200°C. The apparent porosity and water absorption reached the lowest values of 26.68% and 10.99% at 200°C respectively. The bending strength decreased as the temperature increased, reached the highest value of 0.73MPa at 200°C.

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