Properties and Sintering Mechanism of Lightweight Sludge-Flyash-Clay Ceramics

2011 ◽  
Vol 383-390 ◽  
pp. 3346-3351
Author(s):  
Min Yue ◽  
Qin Yan Yue ◽  
Yuan Feng Qi ◽  
Bao Yu Gao ◽  
Hui Yu

This study investigated the properties of lightweight sludge-flyash-clay ceramic by different sintering temperature. Different ratios of dry sewage sludge and fly ash with 50 wt% of clay were mixed and pressed into raw pellets. After drying and preheating treatment, the raw pellets were sintered at temperatures ranging from 1050 to 1150 °C, in 25 °C increments for 10 min. The physical properties (bulk density, grain density, water absorption and rate of expansion) were the indexes used to determine the technical parameters for the preparation of lightweight sludge-fly ash ceramic pellets. The results suggested that temperature was the key control factor of sintering process, and 1150 °C was the starting point of the bloating reaction. In the case of a small fraction in the raw material configuration, the mass ratios of sludge to fly-ash had little effect on the properties.

2010 ◽  
Vol 150-151 ◽  
pp. 1068-1072
Author(s):  
Min Yue ◽  
Qin Yan Yue ◽  
Yuan Feng Qi

The object of this study is to investigate the sintering mechanism of lightweight ceramic by different sintering temperature. The raw materials were sewage sludge and fly-ash, and clay was added as cementing agents (by ratio of 50wt% in each sample). The raw materials were mixed and pressed into raw pellets. After drying and preheating treatment, the raw pellets were sintered at temperatures ranging from 1050 to 1150 , in 25 increments for 10min. The physical properties (bulk density, grain density, water absorption and rate of expansion) were the indexes used to determine the technical parameters for the preparation of lightweight ceramic pellets and investigate the sintering mechanism of bloating. The results suggested that temperature was the key control factor of sintering process, and 1150 was the starting point of bloating reaction. Observation of the microstructure by SEM indicated that a higher flux content in the raw materials could lower the melt point during sintering process.


2014 ◽  
Vol 540 ◽  
pp. 225-228 ◽  
Author(s):  
Long Ma ◽  
Guo Zhong Li ◽  
Ji Rui Hu

The red mud lightweight insulation brick was prepared by the sintering process as red mud, fly ash, bentonite as the main raw material, adding a certain amount of pore forming agent and fluxing agent. The sintering heat preservation time of red mud insulation brick on the properties was studied. The red mud lightweight insulation brick damage fracture microstructure was analyzed using scanning electron microscope (SEM) and the sintering mechanism was discussed preliminarily. The results show that with sintering temperature of 1100°C heating for 180 minutes, the performance of thermal insulation brick is better. When the heat preservation time extends to continue, the performances of sample remain stable basically.


2019 ◽  
Vol 295 ◽  
pp. 105-109
Author(s):  
Ye Li ◽  
Heng Ze Zhao ◽  
Xu Dong Cheng

Adiabatic foam was fabricated successfully using sodium silicate as the raw material with pre-sintered fly ash as additive. Fly ash was pre-sintered at 500 to 900 oC and the effect of the pre-sintering temperature on the performance, including the thermal conductivity, density, compressive strength and microstructure, was researched. The results show that the pre-sintering process effectively reduces the density of the samples while the thermal conductivity and compressive strength are higher than those of the samples fabricated by the fly ash without being pre-sintered. Moreover, the samples exhibit tri-modal spherical pore structure with macropores and mesopores. The pore size remains unchanged until the pre-sintering temperature exceeds 700 oC, and then starts to increase.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3363
Author(s):  
Jolanta Latosińska ◽  
Maria Żygadło ◽  
Przemysław Czapik

Wastewater treatment processes produce sewage sludge (SS), which, in line with environmental sustainability principles, can be a valuable source of matter in the production of lightweight expanded clay aggregate (LECA). The literature on the influence of SS content and sintering temperature on the properties of LECA is scarce. This paper aims to statistically evaluate the effects of SS content and sintering temperature on LECA physical properties. Total porosity, pore volume, and apparent density were determined with the use of a density analyzer. A helium pycnometer was utilized to determine the specific density. Closed porosity was calculated. The test results demonstrated a statistically significant influence of the SS content on the specific density and water absorption of LECA. The sintering temperature had a significant effect on the specific density, apparent density, total porosity, closed porosity, total volume of pores, and water absorption. It was proved that a broad range of the SS content is admissible in the raw material mass for the production of LECA.


2016 ◽  
Vol 881 ◽  
pp. 383-386 ◽  
Author(s):  
Raimundo J.S. Paranhos ◽  
Wilson Acchar ◽  
Vamberto Monteiro Silva

This study evaluated the potential use of Sugarcane Bagasse Ashes (SBA) as a flux, replacing phyllite for the production of enamelled porcelain tile. The raw materials of the standard mass components and the SBA residue were characterized by testing by XRF, XRD, AG, DTA and TGA. Test samples were fabricated, assembled in lots of 3 units and sintered at temperatures of 1150 ° C to 1210 ° C. The results of the physical properties, mechanical properties and SEM of the sintered samples, showed that the formulation, G4 - in which applied 10% of SBA replacing phyllite, sintering temperature 1210 ° C showed better performance as the previously mentioned properties due to the formation of mullite crystals, meeting the prerequisites of standards for enamelled porcelain tile, while reducing the environmental impact and the cost of production.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 596 ◽  
Author(s):  
Andrei Shishkin ◽  
Janis Baronins ◽  
Viktors Mironovs ◽  
František Lukáč ◽  
Igor Štubňa ◽  
...  

A mixture of an illitic clay and waste glass was prepared and studied during the sintering process. The illitic clay, from the Liepa deposit (Latvia), and green glass waste (GW) were disintegrated to obtain a homogeneous mixture. The addition of disintegrated GW (5–15 wt% in the mixture) led to a reduction in the intensive sintering temperature, from 900 to 860 °C, due to a significant decrease in the glass viscosity. The addition of GW slightly decreased the intensities of the endo- and exothermic reactions in the temperature range from 20 to 1000 °C due to the reduced concentration of clay minerals. GW reduced the plasticity of the clay and reduced the risk of structural breakage. The increase in sintering temperature from 700 to 1000 °C decreased the apparent porosity and water uptake capacity of the ceramics from 35% and 22%, down to 24% and 13%, respectively. The apparent porosities of all the sintered mixtures showed a decrease of between 6% to 9% after the addition of GW with concentrations from 5 up to 15 wt% respectively, while the water uptake capacities decreased from between 4% and 10%. The addition of GW led to an increase in the apparent density of the ceramic materials, up to 2.2 g/cm3. Furthermore, the compressive strength increased by more than two times, reaching a highest value of 240 MPa after the sintering of the 15 wt% GW-containing mixture at 1000 °C.


2007 ◽  
Vol 336-338 ◽  
pp. 1130-1132
Author(s):  
Qiang Ren ◽  
Xiu Lan Wu ◽  
Xuan Meng He

High-purity alumina ceramics was prepared using high-purity α-Al2O3 powder as raw material, nitrates or oxides of magnesium, chromium and copper as additives by a wet ball milling with a later dry pressing forming and normal pressure sintering process. The influence of additives on the sintering temperature, microstructure and bending strength of the prepared alumina ceramics was studies. The results showed that the additive doped with nitrate can be dispersed uniformly in the body with molecule scale, and the oxides obtained by decomposing of nitrates have the higher reactivity. Thus, the nitrate additives have better capacity than oxide additives in reducing the sintering temperature and inhibiting the abnormal grain growth, and the alumina ceramics prepared by adding of nitrate additives have higher density and bending strength.


2011 ◽  
Vol 236-238 ◽  
pp. 1523-1527 ◽  
Author(s):  
Xiao Meng Zhang ◽  
Shu Feng Ye ◽  
Li Hua Xu ◽  
Peng Qian ◽  
Lian Qi Wei ◽  
...  

The SiC/FexSiycomposites were synthesized by reaction sintering process with iron tailings as raw material and carbon as reductant. The room and high temperature flexural strengths and fracture toughness of composites were studied in this paper. Fracture surfaces were observed by means of a scanning electron microscope (SEM). The results showed that the room temperature flexural strength of SiC/FexSiycomposites changed along with the different contents of FexSiyand sintering temperature. The flexural strength of composites reaches the maximum at 900°C. The correlation between flexural strength and temperature is consistent with curveⅠ.The fracture toughness of composites is related to the content of FexSiy. The fracture behavior of composites is mainly transcrystalline in room temperature and intercrystalline in high temperature.


2011 ◽  
Vol 295-297 ◽  
pp. 969-973 ◽  
Author(s):  
Jin Hong Li ◽  
Ling Xin Tong ◽  
Lei Hou ◽  
Jie Shen

The effects of MgO and temperature on the properties and microstructure of mullite ceramics synthesized from high-aluminium coal fly ash and bauxite are investigated in this paper. The results show that when the batch containing 4 wt% MgO is heated from 1100 °C to 1500 °C, the bulk density and flexural strength increase obviously with the sintering temperature rising, mullite ceramics with flexural strength as high as 169 MPa can be obtained at 1500 °C with the addition of 2 wt% MgO. According to the XRD results, the corundum, cordierite and cristobalite phases disappear completely upon 1400 °C, it indicates that MgO addition may effectively promote sintering process. The results of SEM indicate that the prepared ceramics mainly exist in the shape of long parallelepipeds with the aspect ratio of about 7-10.


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