Changsha has played a pioneering role in reshaping cross-continental trade and cooperation.From the 50,000 pieces of Changsha Kiln ceramics recovered from the Tang Dynasty shipwreck“Black Stone”to today’s weekly ca...Changsha has played a pioneering role in reshaping cross-continental trade and cooperation.From the 50,000 pieces of Changsha Kiln ceramics recovered from the Tang Dynasty shipwreck“Black Stone”to today’s weekly cargo flights between China and Africa,Changsha’s trade with the African continent has spanned over a thousand years.This historic cultural city is playing an increasingly vital role in China-Africa economic and trade cooperation,with a spirit of innovation and openness.展开更多
This is a historical compilation and analysis of the world-wide development of kilns and furnaces, covering those ones ranging from ancient earthenware kilns to modern high-tech furnaces、 including nuclear reactors a...This is a historical compilation and analysis of the world-wide development of kilns and furnaces, covering those ones ranging from ancient earthenware kilns to modern high-tech furnaces、 including nuclear reactors and fuel cells. Special emphasis is on energy conservation and environmental protection. the historical lessons from which can be applied to future activities.展开更多
JC 497-92 (96)1 Contents and Applied ScopeThis standard specifies the classification, shapes and dimensions, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and qualit...JC 497-92 (96)1 Contents and Applied ScopeThis standard specifies the classification, shapes and dimensions, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and quality certificate of direct-bonded magnesite-chrome bricks for building materials industry. This standard is applicable to the direct-bonded magnesite-chrome bricks for cement kiln, glass melting tank and other industrial furnaces.2 Normative ReferencesGB 2997: Test method for the apparent porosity, water absorption, bulk density and true porosity of dense shaped refractory productsGB 5070: Chemical analysis method for magnesite-Chrome refractoriesGB 5072: Test method for cold crushing strength of dense shaped refractory productsGB 5989: Test method for refractoriness under load of dense shaped refractory products (Differential, with rising temperature)GB 7320: Test method for thermal expansion of refractory productsGB 7321: Sample preparation for testing of dense shaped refractory productsGB 10324: Type definition of refractory productsGB 10325: Piling, sampling, acceptance, storage and transportation of refractory products展开更多
Cement raw meal with MSS and different heavy metals was blended to examine the fixation ratios, chemical species, and cement crystalline phases in clinkers. The results showed that blending MSS could decrease the fixa...Cement raw meal with MSS and different heavy metals was blended to examine the fixation ratios, chemical species, and cement crystalline phases in clinkers. The results showed that blending MSS could decrease the fixation ratio of Cr, Ni, Cu, and Zn in the produced clinker by 5% to 25%. And Cr, Cu, and Zn were mainly incorporated into clinkers as metal silicates, Ni was mainly solubilized in Mg O to form magnesium nickel oxides, and the transition phases were mainly metal aluminum oxides as indicated by X-ray diffraction. The reduction of fixation ratios was likely attributed to the presence of impure elements, such as sodium and phosphorus in MSS. In addition, high concentrations（eg, 1.7 wt%） of chlorine in MSS led to metal chloride formation that could vaporize Cu, Cr, Ni, and Zn. To summarize, introducing MSS would decrease the fixation ratios of heavy metals due to the presence of impure elements, such as sodium and phosphorus and chlorine.展开更多
The behavior of the active layer of material bed within rotary kilns plays a key role in industrial applications.To obtain its influences on industrial process,different regimes of particle motion have been simulated ...The behavior of the active layer of material bed within rotary kilns plays a key role in industrial applications.To obtain its influences on industrial process,different regimes of particle motion have been simulated by discrete element method(DEM) in three dimensions under variant rotation speeds,filling degree,based on the background of induration process of iron ore pellets.The influences of the mentioned factors on the maximum thickness of the active layer and the average velocity of particles have been investigated.The average velocity of particles increases with Froude number following the power function over a wide range,and the maximum thickness rises with increasing rotation speed in a way of logarithm.The influence of the filling degree f on the maximum thickness exhibits a good linearity under two classic regimes,but the increasing of the average velocity of the active layer is limited at f=0.4.This basic research highlights the impact of the active layer within rotary kilns,and lays a good foundation for the further investigation in mixing and heat transfer within the particle bed inside rotary kilns.展开更多
Selective catalytic reduction(SCR)is a technology by which nitrogen oxides are converted with the aid of a catalyst into diatomic nitrogen and water.It is known that the catalyst can be easily eroded if a cement kiln ...Selective catalytic reduction(SCR)is a technology by which nitrogen oxides are converted with the aid of a catalyst into diatomic nitrogen and water.It is known that the catalyst can be easily eroded if a cement kiln with a high-dust content is considered.To understand this process,numerical simulations have been carried out considering a single catalyst channel in order to study the collision and erosion of fly ash and catalysts at meso scale.Based on a response surface methodology,the effects of five factors on the erosion rate have been studied,namely,the catalyst particle velocity,the particle size,the particle concentration,the incidence angle and the catalyst porosity.The results show that the influence of particle velocity,particle size and particle concentration is statistically significant and the particle size and incidence angle have a significant effect on the erosion rate.A quadratic polynomial prediction model for the erosion rate of honeycomb catalysts in cement kiln SCR reactors is finally proposed to support the future optimization of these systems.展开更多
The magnesia -hercynite bricks offer a new lining to rotary cement kiln. They are well adopted and widely used in the high temperature zone of cement kiln, and have obtained good performance at rigorous and severe wor...The magnesia -hercynite bricks offer a new lining to rotary cement kiln. They are well adopted and widely used in the high temperature zone of cement kiln, and have obtained good performance at rigorous and severe working conditions. The synthesis of hercynite requires a suitable atmosphere with proper O2 partial pressures which makes sure FeO can stably exist at the synthesizing temperature. Current industrial production of hercynite mainly adopts fused method. The other method, sinte- ring method, is not mature and needs further research. The magnesia - hercynite brick shows high hot toughhess, high adhesion strength to kiln crust, and good corrosion resistance to alkali salt in cement kilns. The mismatching of thermal expansion between magnesia and hercynite can improve the thermal shock resistance of the bricks, but the oxidation of partial Fe^2＋ , the high temperature solution, and low temperature exsolution of transgranular secondary spinel lead to cubical expansion, .formation of more cracks, and poor thermal shock resistance of the bricks.展开更多
There are many factors affecting the monolithic lining engineering of rotary kilns,resulting in the difficult quality control.In this paper,the key points of the whole lining engineering were discussed from the aspect...There are many factors affecting the monolithic lining engineering of rotary kilns,resulting in the difficult quality control.In this paper,the key points of the whole lining engineering were discussed from the aspects of lining structure design,personnel preparation,site construction management,maintenance and baking.展开更多
Corrosion of burning urban domestic wastes to alkali-resistant bricks and spalling-resistant high alumina bricks was researched by static crucible method and SEM in order to choose refractories for cement rotary kilns...Corrosion of burning urban domestic wastes to alkali-resistant bricks and spalling-resistant high alumina bricks was researched by static crucible method and SEM in order to choose refractories for cement rotary kilns for collaboratively disposing wastes. The result indicates that the main corrosion mechanism is slag permeation and corrosion ; the emitted high temperature gases containing alkali, sulfur and chlorine during burning the wastes re- act with refractories forming low melting point sulfate, chloride and compound salts, which metamorphose the refractories, and the loose metamorphic layer is easy to spall under thermal stress. So, corrosion resistance and spaUing resistance shall be taken into account when choosing refractories for cement rotary kilns for collaboratively disposing wastes. It is suggested that decomposition furnaces should adopt spaUing resistant high alumina bricks and anti-coating SiC castables, and preheating equipment should adopt high strength alkali-resistant bricks and castables.展开更多
This paper introduces the refractories used in various nonferrous metal smelting equipment in China and the existing problems, and puts forward suggestions on the material of refractories, application of new technolog...This paper introduces the refractories used in various nonferrous metal smelting equipment in China and the existing problems, and puts forward suggestions on the material of refractories, application of new technologies and production management of refractories, etc.展开更多
In order to improve the service performance and explore the damage mechanism of silicon carbide-mullite bricks for the transition zone of cement rotary kilns,the phase composition and the microstructure of a used bric...In order to improve the service performance and explore the damage mechanism of silicon carbide-mullite bricks for the transition zone of cement rotary kilns,the phase composition and the microstructure of a used brick in the transition zone of a cement rotary kiln were analyzed by XRD,SEM and EDS.The results show that the liquid and alkali vapor phases generated by the reaction between cement materials and the silicon carbide-mullite brick mostly enter the silicon carbide-mullite brick through the pores;meanwhile,Ca+and K+in the cement penetrate through the liquid maintaining a high chemical potential energy to dissolve Al2O3 and SiO2 at the top of the liquid phase thus enhancing the phase penetration;with the decreasing temperature,crystals such as gehlenite,potassium feldspar and potassium chloride are precipitated,which destroy the original structure and increase the difference of thermal expansion coefficient between the high temperature dense end and the metamorphic layer thus resulting in cracks,spalling,and rupture.展开更多
To provide a material with excellent comprehensive properties for the glass kiln melting pools,zirconia powder and alumina powder were fully mixed according to the ratio of m(ZrO_(2)):m(Al_(2)O_(3))=4:1 and fused in a...To provide a material with excellent comprehensive properties for the glass kiln melting pools,zirconia powder and alumina powder were fully mixed according to the ratio of m(ZrO_(2)):m(Al_(2)O_(3))=4:1 and fused in an arc furnace.The obtained fused zirconia-corundum eutectic material was processed into different particle sizes,batched according to a certain particle size distribution and mixed evenly.After pressure molding and firing at 1750℃,new zirconia-based composites were prepared.The phase composition and microstructure of the composites were analyzed.The molten glass corrosion resistance of the composites was compared with that of zirconia corundum bricks 33#and 41#.The results show that the new zirconia-based composites have a dense structure,high chemical purity without low melting point components,and good thermal shock resistance.Compared with zirconia corundum bricks 33#and 41#,after being corroded by high temperature molten glass,the new composites have no corrosion cavities,needle-like pores,defects or liquid phase infiltration,and no reaction with molten glass,showing good corrosion resistance to molten glass.展开更多
The digital manufacturing theory is applied to the special manufacturing equipments——industrial kilns and furnaces;the concept of digital kilns&furnaces is put forward.The present status of research and applicat...The digital manufacturing theory is applied to the special manufacturing equipments——industrial kilns and furnaces;the concept of digital kilns&furnaces is put forward.The present status of research and application for digital technologies in fuel industrial kilns&furnaces is also introduced.Then,take the case of gas fuel kilns&furnaces,their main key technical issues are discussed.Digital kilns&furnaces as an important constituent of the digital equipments are the crucial base of the digital manufacturing.The value of research on digital kilns&furnaces and the application prospect are undoubted.It will improve product quality,reduce the manpower cost,enhance product market competitive ability,promote comprehensively tradition industries such as ceramics,metallurgy industry,and so on.展开更多
From the 50,000 pieces of Changsha Kiln ceramics recovered from the Tang Dynasty(618-907)shipwreck Black Stone to today's weekly cargo flights between China and Africa,Changsha's trade with the African contine...From the 50,000 pieces of Changsha Kiln ceramics recovered from the Tang Dynasty(618-907)shipwreck Black Stone to today's weekly cargo flights between China and Africa,Changsha's trade with the African continent has spanned over 1,000 years.This historic cultural city,capital of Hunan Province,is playing an increasingly vital role in China-Africa economic and trade cooperation,with a spirit of innovation and openness.展开更多
In this study, a mathematical model based on the segregation-induced ring-core structure was developed to predict the residence time and axial velocity of particles of different sizes within a rotary kiln. Validation ...In this study, a mathematical model based on the segregation-induced ring-core structure was developed to predict the residence time and axial velocity of particles of different sizes within a rotary kiln. Validation experiments were conducted using a pilot-scale rotary kiln with bidisperse particle systems comprising particle sizes of 0.7 mm, 2 mm, and 4 mm. The entire process was recorded using video analysis, which enabled the tracking of tracer particle movement from the inlet to the outlet. Based on the recorded data, the average axial velocity for each particle size across different kiln regions was determined. At the outlet, the tracer particles were analyzed using statistical methods and diffusion theory, allowing for the calculation of the residence time distribution (RTD), mean residence time (MRT), variance, axial dispersion coefficient (Dz), and Peclet number (Pe). The experimentally obtained MRT exhibited strong agreement with the predictions of the mathematical ring-core structure model, confirming its accuracy and reliability. Additionally, the influence of particle size and mixing behavior was systematically evaluated by varying particle size ratios and mass concentrations.展开更多
Aiming at the characteristics of carbon black,a new method of controlling the black smoke from the industrial coal-burning ceramic kilns by wetting was brought forward.The carbon black in the flue of coal-burning cera...Aiming at the characteristics of carbon black,a new method of controlling the black smoke from the industrial coal-burning ceramic kilns by wetting was brought forward.The carbon black in the flue of coal-burning ceramic kiln was collected for the experiments,and its physical and chemical properties were studied in detail.In order to change the sedimentation and wettabil-ity state of the carbon black,the complex solution of the coagulant and surfactant was applied.After a series of orthogonal experiments,the complex solutions with bet-ter effects were chosen.Then,the sedimentation percent-age of carbon black treated by the selected complex solutions was measured.The optimized complex solutions included Na 2 SO 4(100 mmol/L),sodium dodecylbenzene-sulfonate(SDBS)(1.2 mmol/L)and polyacrylamide(PAM)(40 mg/L).After carbon black was absorbed,the complex solutions were clear and colorless.The complex solutions can be recycled,and the sedimentation percent-age of carbon black is 94%.展开更多
Brick kiln is well known as one of the main sources of air pollution;however,the pollutants produced from it do not remain in the air,they ultimately fall down to the soil and pollute the surroundings,therefore,this s...Brick kiln is well known as one of the main sources of air pollution;however,the pollutants produced from it do not remain in the air,they ultimately fall down to the soil and pollute the surroundings,therefore,this study was carried out to assess the status of macro(N,P,K and S)and micro nutrients(Fe,Mn and Zn,Cu)in the agricultural environment near the brick kilns of Young Brahmaputra and Jamuna Floodplain soils.Composite soil and plant samples were collected from four distances such as 250 m,500 m,1000 m,and 1500 m in three different sites.Sulphur(2352-3378 mg kg^-1),Zn(86-156 mg kg^-1)and Cu(24.7-46.9 mg kg^-1)are found in the elevated levels near brick kiln soils that is released due to burning of poor quality coal and fire woods.The alarming news is that plant uptake of S and micro nutrients in the nearest areas of the brick kilns are significantly higher than the areas far from the brick production and their concentration ranges from 23 mg kg^-1 to 101 mg kg^-1 for Zn,10-41 mg kg^-1 for Cu,35-1309 mg kg^-1 for Fe,26-126 mg kg^-1 for Mn and 2590-mg kg^-1 for S.Data indicates both soil and plant received maximum amount of micronutrients and S concentrations within 500-1000 m distances from brick kilns.Iron and Mn concentrations vary within a permissible limit but the plant uptake is high.Nitrogen concentrations is increasing with the distance from the brick kilns in both soils and plants but no definite pattern of P and K accumulation was found.Research suggested avoiding agricultural practice nearby brick kiln soils due to micronutrient contamination in order to preserve adjoined agricultural environment.展开更多
Charcoal kilns,old structures used for charcoal production in the forest,preserve a charcoal-enriched topsoil representing a suitable proxy for studying the long-term effect of biochar addition to soil.Two kiln platfo...Charcoal kilns,old structures used for charcoal production in the forest,preserve a charcoal-enriched topsoil representing a suitable proxy for studying the long-term effect of biochar addition to soil.Two kiln platforms located at Gelbison and Vesole mountain sites in Southern Italy were selected due to their comparable climates but distinct parent rocks.We conducted standard soil chemical analyses and used next-generation sequencing to explore bacterial and fungal microbiome.Anthracology identified charcoal species,while scanning electron microscopy(SEM)with energy dispersive X-ray spectroscopy(EDS)characterized charcoal particles.Reflectance Fourier transform infrared spectroscopy(DRIFTS)assessed biochar surface oxidation.Additionally,a bioassay with soybean,maize,and Tomato investigated the impact of kiln soil on plant performance.Our results showed that kiln soils did not exhibit higher pH,cation exchange capacity,or greater richness in cations.EDS and FTIR analyses showed that charcoal buried in forest soil for decades undergoes significant oxidation,with increased O/C ratio and the presence of oxygenated functional groups.Charcoal surfaces were selectively enriched with Ca^(2+)on limestone substrate sites but with Al and Si over sedimentary(flysch)substrate.While differences in the kiln soil and its surroundings were noticeable,they were not drastic in terms of microbial diversity and composition.Surprisingly,the bioassay indicated that the kiln microbiota had a more positive impact on plant growth compared to external forest soil.In conclusion,this study highlights the unique nature of kiln microsites and begins to unveil the enduring effects of charcoal accumulation on soil chemistry and microbiota in forest soil.展开更多
A television documentary and better transportation have brought illegal treasure hunters to Minqing County with devastating results for the region’s ancient kilns In Yiyou Village,Minqing County in south China’s Fuj...A television documentary and better transportation have brought illegal treasure hunters to Minqing County with devastating results for the region’s ancient kilns In Yiyou Village,Minqing County in south China’s Fujian Province ancient ceramic bowls,kettles and cups fitter the ground.The ancient treasures are relics from the Song and Yuan dynasties and date back almost a thousand years.展开更多
文摘Changsha has played a pioneering role in reshaping cross-continental trade and cooperation.From the 50,000 pieces of Changsha Kiln ceramics recovered from the Tang Dynasty shipwreck“Black Stone”to today’s weekly cargo flights between China and Africa,Changsha’s trade with the African continent has spanned over a thousand years.This historic cultural city is playing an increasingly vital role in China-Africa economic and trade cooperation,with a spirit of innovation and openness.
文摘This is a historical compilation and analysis of the world-wide development of kilns and furnaces, covering those ones ranging from ancient earthenware kilns to modern high-tech furnaces、 including nuclear reactors and fuel cells. Special emphasis is on energy conservation and environmental protection. the historical lessons from which can be applied to future activities.
文摘JC 497-92 (96)1 Contents and Applied ScopeThis standard specifies the classification, shapes and dimensions, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and quality certificate of direct-bonded magnesite-chrome bricks for building materials industry. This standard is applicable to the direct-bonded magnesite-chrome bricks for cement kiln, glass melting tank and other industrial furnaces.2 Normative ReferencesGB 2997: Test method for the apparent porosity, water absorption, bulk density and true porosity of dense shaped refractory productsGB 5070: Chemical analysis method for magnesite-Chrome refractoriesGB 5072: Test method for cold crushing strength of dense shaped refractory productsGB 5989: Test method for refractoriness under load of dense shaped refractory products (Differential, with rising temperature)GB 7320: Test method for thermal expansion of refractory productsGB 7321: Sample preparation for testing of dense shaped refractory productsGB 10324: Type definition of refractory productsGB 10325: Piling, sampling, acceptance, storage and transportation of refractory products
基金the National Major Science and Technology Project of Water Pollution Control and Management,China(No.2010ZX07319-001-02)
文摘Cement raw meal with MSS and different heavy metals was blended to examine the fixation ratios, chemical species, and cement crystalline phases in clinkers. The results showed that blending MSS could decrease the fixation ratio of Cr, Ni, Cu, and Zn in the produced clinker by 5% to 25%. And Cr, Cu, and Zn were mainly incorporated into clinkers as metal silicates, Ni was mainly solubilized in Mg O to form magnesium nickel oxides, and the transition phases were mainly metal aluminum oxides as indicated by X-ray diffraction. The reduction of fixation ratios was likely attributed to the presence of impure elements, such as sodium and phosphorus in MSS. In addition, high concentrations（eg, 1.7 wt%） of chlorine in MSS led to metal chloride formation that could vaporize Cu, Cr, Ni, and Zn. To summarize, introducing MSS would decrease the fixation ratios of heavy metals due to the presence of impure elements, such as sodium and phosphorus and chlorine.
基金Project(FRF-AS-10-0058) supported by the Fundamental Research Funds for the Central Universities,China
文摘The behavior of the active layer of material bed within rotary kilns plays a key role in industrial applications.To obtain its influences on industrial process,different regimes of particle motion have been simulated by discrete element method(DEM) in three dimensions under variant rotation speeds,filling degree,based on the background of induration process of iron ore pellets.The influences of the mentioned factors on the maximum thickness of the active layer and the average velocity of particles have been investigated.The average velocity of particles increases with Froude number following the power function over a wide range,and the maximum thickness rises with increasing rotation speed in a way of logarithm.The influence of the filling degree f on the maximum thickness exhibits a good linearity under two classic regimes,but the increasing of the average velocity of the active layer is limited at f=0.4.This basic research highlights the impact of the active layer within rotary kilns,and lays a good foundation for the further investigation in mixing and heat transfer within the particle bed inside rotary kilns.
基金supported by the Eco-Environment Project of the Key Research and Development Program of Anhui Province(No.202104i07020016).
文摘Selective catalytic reduction(SCR)is a technology by which nitrogen oxides are converted with the aid of a catalyst into diatomic nitrogen and water.It is known that the catalyst can be easily eroded if a cement kiln with a high-dust content is considered.To understand this process,numerical simulations have been carried out considering a single catalyst channel in order to study the collision and erosion of fly ash and catalysts at meso scale.Based on a response surface methodology,the effects of five factors on the erosion rate have been studied,namely,the catalyst particle velocity,the particle size,the particle concentration,the incidence angle and the catalyst porosity.The results show that the influence of particle velocity,particle size and particle concentration is statistically significant and the particle size and incidence angle have a significant effect on the erosion rate.A quadratic polynomial prediction model for the erosion rate of honeycomb catalysts in cement kiln SCR reactors is finally proposed to support the future optimization of these systems.
文摘The magnesia -hercynite bricks offer a new lining to rotary cement kiln. They are well adopted and widely used in the high temperature zone of cement kiln, and have obtained good performance at rigorous and severe working conditions. The synthesis of hercynite requires a suitable atmosphere with proper O2 partial pressures which makes sure FeO can stably exist at the synthesizing temperature. Current industrial production of hercynite mainly adopts fused method. The other method, sinte- ring method, is not mature and needs further research. The magnesia - hercynite brick shows high hot toughhess, high adhesion strength to kiln crust, and good corrosion resistance to alkali salt in cement kilns. The mismatching of thermal expansion between magnesia and hercynite can improve the thermal shock resistance of the bricks, but the oxidation of partial Fe^2＋ , the high temperature solution, and low temperature exsolution of transgranular secondary spinel lead to cubical expansion, .formation of more cracks, and poor thermal shock resistance of the bricks.
文摘There are many factors affecting the monolithic lining engineering of rotary kilns,resulting in the difficult quality control.In this paper,the key points of the whole lining engineering were discussed from the aspects of lining structure design,personnel preparation,site construction management,maintenance and baking.
文摘Corrosion of burning urban domestic wastes to alkali-resistant bricks and spalling-resistant high alumina bricks was researched by static crucible method and SEM in order to choose refractories for cement rotary kilns for collaboratively disposing wastes. The result indicates that the main corrosion mechanism is slag permeation and corrosion ; the emitted high temperature gases containing alkali, sulfur and chlorine during burning the wastes re- act with refractories forming low melting point sulfate, chloride and compound salts, which metamorphose the refractories, and the loose metamorphic layer is easy to spall under thermal stress. So, corrosion resistance and spaUing resistance shall be taken into account when choosing refractories for cement rotary kilns for collaboratively disposing wastes. It is suggested that decomposition furnaces should adopt spaUing resistant high alumina bricks and anti-coating SiC castables, and preheating equipment should adopt high strength alkali-resistant bricks and castables.
文摘This paper introduces the refractories used in various nonferrous metal smelting equipment in China and the existing problems, and puts forward suggestions on the material of refractories, application of new technologies and production management of refractories, etc.
文摘In order to improve the service performance and explore the damage mechanism of silicon carbide-mullite bricks for the transition zone of cement rotary kilns,the phase composition and the microstructure of a used brick in the transition zone of a cement rotary kiln were analyzed by XRD,SEM and EDS.The results show that the liquid and alkali vapor phases generated by the reaction between cement materials and the silicon carbide-mullite brick mostly enter the silicon carbide-mullite brick through the pores;meanwhile,Ca+and K+in the cement penetrate through the liquid maintaining a high chemical potential energy to dissolve Al2O3 and SiO2 at the top of the liquid phase thus enhancing the phase penetration;with the decreasing temperature,crystals such as gehlenite,potassium feldspar and potassium chloride are precipitated,which destroy the original structure and increase the difference of thermal expansion coefficient between the high temperature dense end and the metamorphic layer thus resulting in cracks,spalling,and rupture.
文摘To provide a material with excellent comprehensive properties for the glass kiln melting pools,zirconia powder and alumina powder were fully mixed according to the ratio of m(ZrO_(2)):m(Al_(2)O_(3))=4:1 and fused in an arc furnace.The obtained fused zirconia-corundum eutectic material was processed into different particle sizes,batched according to a certain particle size distribution and mixed evenly.After pressure molding and firing at 1750℃,new zirconia-based composites were prepared.The phase composition and microstructure of the composites were analyzed.The molten glass corrosion resistance of the composites was compared with that of zirconia corundum bricks 33#and 41#.The results show that the new zirconia-based composites have a dense structure,high chemical purity without low melting point components,and good thermal shock resistance.Compared with zirconia corundum bricks 33#and 41#,after being corroded by high temperature molten glass,the new composites have no corrosion cavities,needle-like pores,defects or liquid phase infiltration,and no reaction with molten glass,showing good corrosion resistance to molten glass.
文摘The digital manufacturing theory is applied to the special manufacturing equipments——industrial kilns and furnaces;the concept of digital kilns&furnaces is put forward.The present status of research and application for digital technologies in fuel industrial kilns&furnaces is also introduced.Then,take the case of gas fuel kilns&furnaces,their main key technical issues are discussed.Digital kilns&furnaces as an important constituent of the digital equipments are the crucial base of the digital manufacturing.The value of research on digital kilns&furnaces and the application prospect are undoubted.It will improve product quality,reduce the manpower cost,enhance product market competitive ability,promote comprehensively tradition industries such as ceramics,metallurgy industry,and so on.
文摘From the 50,000 pieces of Changsha Kiln ceramics recovered from the Tang Dynasty(618-907)shipwreck Black Stone to today's weekly cargo flights between China and Africa,Changsha's trade with the African continent has spanned over 1,000 years.This historic cultural city,capital of Hunan Province,is playing an increasingly vital role in China-Africa economic and trade cooperation,with a spirit of innovation and openness.
基金funded by the European Regional Development Fund(ERDF)through the EU-ERDF Saxony-Anhalt program,within the project“Competence Network for Applied and Transfer-Oriented Research”(KAT)ZS/2023/12/182020the project“Thermal Recycling of Lithium Batteries”ZS/2023/12/182014.
文摘In this study, a mathematical model based on the segregation-induced ring-core structure was developed to predict the residence time and axial velocity of particles of different sizes within a rotary kiln. Validation experiments were conducted using a pilot-scale rotary kiln with bidisperse particle systems comprising particle sizes of 0.7 mm, 2 mm, and 4 mm. The entire process was recorded using video analysis, which enabled the tracking of tracer particle movement from the inlet to the outlet. Based on the recorded data, the average axial velocity for each particle size across different kiln regions was determined. At the outlet, the tracer particles were analyzed using statistical methods and diffusion theory, allowing for the calculation of the residence time distribution (RTD), mean residence time (MRT), variance, axial dispersion coefficient (Dz), and Peclet number (Pe). The experimentally obtained MRT exhibited strong agreement with the predictions of the mathematical ring-core structure model, confirming its accuracy and reliability. Additionally, the influence of particle size and mixing behavior was systematically evaluated by varying particle size ratios and mass concentrations.
基金This work was supported by the Trans-Century Training Program Foundation for the Talent of China(Grant No.NCET-04-0769)the Key Program of the Ministry of Education of China(Grant No.105126)the Key Program of the Natural Science Foundation of Hunan Province,China(Grant No.03JJY2002).
文摘Aiming at the characteristics of carbon black,a new method of controlling the black smoke from the industrial coal-burning ceramic kilns by wetting was brought forward.The carbon black in the flue of coal-burning ceramic kiln was collected for the experiments,and its physical and chemical properties were studied in detail.In order to change the sedimentation and wettabil-ity state of the carbon black,the complex solution of the coagulant and surfactant was applied.After a series of orthogonal experiments,the complex solutions with bet-ter effects were chosen.Then,the sedimentation percent-age of carbon black treated by the selected complex solutions was measured.The optimized complex solutions included Na 2 SO 4(100 mmol/L),sodium dodecylbenzene-sulfonate(SDBS)(1.2 mmol/L)and polyacrylamide(PAM)(40 mg/L).After carbon black was absorbed,the complex solutions were clear and colorless.The complex solutions can be recycled,and the sedimentation percent-age of carbon black is 94%.
文摘Brick kiln is well known as one of the main sources of air pollution;however,the pollutants produced from it do not remain in the air,they ultimately fall down to the soil and pollute the surroundings,therefore,this study was carried out to assess the status of macro(N,P,K and S)and micro nutrients(Fe,Mn and Zn,Cu)in the agricultural environment near the brick kilns of Young Brahmaputra and Jamuna Floodplain soils.Composite soil and plant samples were collected from four distances such as 250 m,500 m,1000 m,and 1500 m in three different sites.Sulphur(2352-3378 mg kg^-1),Zn(86-156 mg kg^-1)and Cu(24.7-46.9 mg kg^-1)are found in the elevated levels near brick kiln soils that is released due to burning of poor quality coal and fire woods.The alarming news is that plant uptake of S and micro nutrients in the nearest areas of the brick kilns are significantly higher than the areas far from the brick production and their concentration ranges from 23 mg kg^-1 to 101 mg kg^-1 for Zn,10-41 mg kg^-1 for Cu,35-1309 mg kg^-1 for Fe,26-126 mg kg^-1 for Mn and 2590-mg kg^-1 for S.Data indicates both soil and plant received maximum amount of micronutrients and S concentrations within 500-1000 m distances from brick kilns.Iron and Mn concentrations vary within a permissible limit but the plant uptake is high.Nitrogen concentrations is increasing with the distance from the brick kilns in both soils and plants but no definite pattern of P and K accumulation was found.Research suggested avoiding agricultural practice nearby brick kiln soils due to micronutrient contamination in order to preserve adjoined agricultural environment.
文摘Charcoal kilns,old structures used for charcoal production in the forest,preserve a charcoal-enriched topsoil representing a suitable proxy for studying the long-term effect of biochar addition to soil.Two kiln platforms located at Gelbison and Vesole mountain sites in Southern Italy were selected due to their comparable climates but distinct parent rocks.We conducted standard soil chemical analyses and used next-generation sequencing to explore bacterial and fungal microbiome.Anthracology identified charcoal species,while scanning electron microscopy(SEM)with energy dispersive X-ray spectroscopy(EDS)characterized charcoal particles.Reflectance Fourier transform infrared spectroscopy(DRIFTS)assessed biochar surface oxidation.Additionally,a bioassay with soybean,maize,and Tomato investigated the impact of kiln soil on plant performance.Our results showed that kiln soils did not exhibit higher pH,cation exchange capacity,or greater richness in cations.EDS and FTIR analyses showed that charcoal buried in forest soil for decades undergoes significant oxidation,with increased O/C ratio and the presence of oxygenated functional groups.Charcoal surfaces were selectively enriched with Ca^(2+)on limestone substrate sites but with Al and Si over sedimentary(flysch)substrate.While differences in the kiln soil and its surroundings were noticeable,they were not drastic in terms of microbial diversity and composition.Surprisingly,the bioassay indicated that the kiln microbiota had a more positive impact on plant growth compared to external forest soil.In conclusion,this study highlights the unique nature of kiln microsites and begins to unveil the enduring effects of charcoal accumulation on soil chemistry and microbiota in forest soil.
文摘A television documentary and better transportation have brought illegal treasure hunters to Minqing County with devastating results for the region’s ancient kilns In Yiyou Village,Minqing County in south China’s Fujian Province ancient ceramic bowls,kettles and cups fitter the ground.The ancient treasures are relics from the Song and Yuan dynasties and date back almost a thousand years.
