In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositio...In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositions and microstructures were tested by XRD,SEM and EPMA.The experimental results show that the water absorption is 45.64%,the porosity is 58.91%,bulk density is 1.29 g·cm-3,compressive strength is 54.91 MPa,bending strength is 29.52 MPa,freeze-thaw resistance is 29.28 MPa,specific heat capacity at constant pressure is 1.31 J·g-1·K-1,thermal diffusivity is 5.89×10-3 cm2·s-1,and thermal conductivity is 1.15×10-2 W·cm-1·K-1.These effects of additives and preparation process to the properties and microstructures were discussed in detail.The reaction mechanism was also discussed.The results of the reaction mechanism show that there has wollastonite and feldspar generated during the process of firing while Ca gathered around the feldspar,and then Ca would displace K and generated cacoclasite.展开更多
A ceramic gas turbine can save energy because of its high thermal efficiency at high turbine inlet temperatures. This paper deals with the thermodynamic and economic aspects of a ceramic gas turbine cogeneration syste...A ceramic gas turbine can save energy because of its high thermal efficiency at high turbine inlet temperatures. This paper deals with the thermodynamic and economic aspects of a ceramic gas turbine cogeneration system. Here cogeneration means the simultaneous production of electrical en-ergy and useful thermal energy from the same facility. The thermodynamic performance of a ceramic gas turbine cycle is assessed using a computer model. This model is used in parametric studies of performance under partial loads and at various inlet air temperatures. The computed performance is compared to the measured performance of a conventional gas turbine cycle. Then, an economic evaluation of a ceramic gas turbine cogeneration system is investigated. Energy savings provided by this system are estimated on the basis of the distributions of heat/power ratios. The computed economic evaluation is compared to the actual economic performance of a conventional system in which boilers produce the required thermal energy and electricity is purchased from a utility.展开更多
1 Scope This standard specifies the classification, brand, technical requirements, shape and dimension, test method, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of e...1 Scope This standard specifies the classification, brand, technical requirements, shape and dimension, test method, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of eordierite bricks for ceramic burner of blast furnace and hot blast stove.展开更多
In order to utilize solid wastes, ceramic facing brick was made form East-lake sediment and some additives. The strength and freeze-thaw resistance of the samples were tested, and the crystal phases and microstructure...In order to utilize solid wastes, ceramic facing brick was made form East-lake sediment and some additives. The strength and freeze-thaw resistance of the samples were tested, and the crystal phases and microstructures were studied by XRD and SEM. The results indicate that the samples have a wide firing temperature range. The main crystal phases are CaA12SizOs, a-Al203, Fe203, which distribute uniformly in the samples. The sample have the best properties in the series ＇Ca-A1-Si＇, and water absorption （Wa）, porosity （Pa）, bulk density （D）, bending strength and compressive strength are 7.24%, 15.82%, 2.19 g.cm＂3, 45.57 MPa and 56.81 MPa respectively, when the addition amount of East-lake sediment is 80% and the firing temperature is 1 100 ~C. In the series ＇K-A1-Si＇, the sample with the best properties was obtained when addition amount of East-lake sediment was 70% and firing temperature was 1 060 ~C. The water absorption, porosity, bulk density, bending strength and compressive strength are 7.62%, 16.37%, 2.15 g ~ cm＂3, 39.26 MPa, and 50.81 MPa respectively. They all come up to the national standardization, and meet the needs of manufacturing production.展开更多
Particle size analysis, Atterberg limits, X-ray diffraction, X-ray fluorescence and firing tests were used to determine physico-chemical, mineralogical and technological characteristics of residual lateritic (K1M, Ma2...Particle size analysis, Atterberg limits, X-ray diffraction, X-ray fluorescence and firing tests were used to determine physico-chemical, mineralogical and technological characteristics of residual lateritic (K1M, Ma2) and alluvial (KB3, KG3) clays from Foumban (West-Cameroon). For technological properties, the samples were pressed and fired over a temperature range of 900°C - 1200°C to determine the open porosity, linear shrinkage, bulk density and compressive strength. Kaolinite (31% - 65%) and quartz (35% - 50%) are dominant in Foumban clays with accessory K-feldspar, plagioclase, illite, smectite, rutile, and goethite. But their proportion changes from one sample to another, having a significant effect on the behaviour of the clay materials: highest proportion of quartz (50%) in sample K1M;relative high feldspars (20%) and illite contents (10%) in KB3 and MA2;high smectite content in KG3 (up to 20%). Chemical analyses indicate high SiO2 (49% - 77%) and low Al2O3 (14% - 23%) contents in the four samples, with comparatively low contents of iron oxides (4% - 7% in samples KB3 and KG3, 2.5% in MA2 and ~1.5% in sample K1M). The particle size distribution of the alluvial clays (KG3 and KB3) differs considerably: 7% to 37% of clay fraction, 20% to 78% of silt, and 15% to 58% of sand, while residual clays (K1M and MA2) present on average 12% of clay, 51% of silt and 37% of sand. Two raw clays (KB3 and MA2) can be used for bricks/tiles production without beneficiation or addition. K1M requires some flux addition to decrease the sintering temperature while KG3 presents poor properties due to the combined occurrence of smectite and a high clayey fraction (37%). Such mineralogical composition is responsible for very high plasticity (PI: 50), high shrinkage (LS: 5% - 16%), low porosity (OP: up to 21%) and high flexural strength (FS: 16 - 23 N/mm2) above 1050°C. This last clay is therefore less appropriate for bricks and roofing tiles production since degreasers must be added to the raw material.展开更多
The effect of compositions of saw dust admixture on thermal conductivity and other mechanical/refractory properties of Ifon Clay was investigated. The raw clay gotten from Ifon in Ondo state was first processed to ver...The effect of compositions of saw dust admixture on thermal conductivity and other mechanical/refractory properties of Ifon Clay was investigated. The raw clay gotten from Ifon in Ondo state was first processed to very fine particles and characterized using SEM/EDX, XRD and XRF. Sawdust from mahogany tree procured from a saw mill in Akure the State capital of Ondo State was also dried to remove moisture present. A composite mixture of this dried saw dust with the processed clay was made at various proportions of the saw dust, with a little addition of water for plasticity. Sam- ples of cylindrical dimensions were then produced from the mounting press by the process of compaction with a very high pressure. The samples were dried and then finally fired in the furnace at 1000?C for a final curing. Properties which include thermal shock resistance, bulk density, cold crushing strength, thermal conductivity and porosity were obtained by the appropriate standard test methods. The microstructures of the fired samples were also characterized with SEM using back scattered secondary imaging. The results show that the amount of sawdust admixture affects the properties variously;porosity increases with percentage increase in sawdust admixture while the thermal conductivity and other properties of the sample reduce with percentage increase in sawdust admixture. It was concluded that for structural insulating bricks where compressive strength is important the sawdust admixture should not exceed 10 to 15 percent.展开更多
基金Funded by the 11th Five-Year National Key Technology R&D Program(2008BAC41B00)
文摘In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositions and microstructures were tested by XRD,SEM and EPMA.The experimental results show that the water absorption is 45.64%,the porosity is 58.91%,bulk density is 1.29 g·cm-3,compressive strength is 54.91 MPa,bending strength is 29.52 MPa,freeze-thaw resistance is 29.28 MPa,specific heat capacity at constant pressure is 1.31 J·g-1·K-1,thermal diffusivity is 5.89×10-3 cm2·s-1,and thermal conductivity is 1.15×10-2 W·cm-1·K-1.These effects of additives and preparation process to the properties and microstructures were discussed in detail.The reaction mechanism was also discussed.The results of the reaction mechanism show that there has wollastonite and feldspar generated during the process of firing while Ca gathered around the feldspar,and then Ca would displace K and generated cacoclasite.
文摘A ceramic gas turbine can save energy because of its high thermal efficiency at high turbine inlet temperatures. This paper deals with the thermodynamic and economic aspects of a ceramic gas turbine cogeneration system. Here cogeneration means the simultaneous production of electrical en-ergy and useful thermal energy from the same facility. The thermodynamic performance of a ceramic gas turbine cycle is assessed using a computer model. This model is used in parametric studies of performance under partial loads and at various inlet air temperatures. The computed performance is compared to the measured performance of a conventional gas turbine cycle. Then, an economic evaluation of a ceramic gas turbine cogeneration system is investigated. Energy savings provided by this system are estimated on the basis of the distributions of heat/power ratios. The computed economic evaluation is compared to the actual economic performance of a conventional system in which boilers produce the required thermal energy and electricity is purchased from a utility.
文摘1 Scope This standard specifies the classification, brand, technical requirements, shape and dimension, test method, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of eordierite bricks for ceramic burner of blast furnace and hot blast stove.
文摘In order to utilize solid wastes, ceramic facing brick was made form East-lake sediment and some additives. The strength and freeze-thaw resistance of the samples were tested, and the crystal phases and microstructures were studied by XRD and SEM. The results indicate that the samples have a wide firing temperature range. The main crystal phases are CaA12SizOs, a-Al203, Fe203, which distribute uniformly in the samples. The sample have the best properties in the series ＇Ca-A1-Si＇, and water absorption （Wa）, porosity （Pa）, bulk density （D）, bending strength and compressive strength are 7.24%, 15.82%, 2.19 g.cm＂3, 45.57 MPa and 56.81 MPa respectively, when the addition amount of East-lake sediment is 80% and the firing temperature is 1 100 ~C. In the series ＇K-A1-Si＇, the sample with the best properties was obtained when addition amount of East-lake sediment was 70% and firing temperature was 1 060 ~C. The water absorption, porosity, bulk density, bending strength and compressive strength are 7.62%, 16.37%, 2.15 g ~ cm＂3, 39.26 MPa, and 50.81 MPa respectively. They all come up to the national standardization, and meet the needs of manufacturing production.
文摘Particle size analysis, Atterberg limits, X-ray diffraction, X-ray fluorescence and firing tests were used to determine physico-chemical, mineralogical and technological characteristics of residual lateritic (K1M, Ma2) and alluvial (KB3, KG3) clays from Foumban (West-Cameroon). For technological properties, the samples were pressed and fired over a temperature range of 900°C - 1200°C to determine the open porosity, linear shrinkage, bulk density and compressive strength. Kaolinite (31% - 65%) and quartz (35% - 50%) are dominant in Foumban clays with accessory K-feldspar, plagioclase, illite, smectite, rutile, and goethite. But their proportion changes from one sample to another, having a significant effect on the behaviour of the clay materials: highest proportion of quartz (50%) in sample K1M;relative high feldspars (20%) and illite contents (10%) in KB3 and MA2;high smectite content in KG3 (up to 20%). Chemical analyses indicate high SiO2 (49% - 77%) and low Al2O3 (14% - 23%) contents in the four samples, with comparatively low contents of iron oxides (4% - 7% in samples KB3 and KG3, 2.5% in MA2 and ~1.5% in sample K1M). The particle size distribution of the alluvial clays (KG3 and KB3) differs considerably: 7% to 37% of clay fraction, 20% to 78% of silt, and 15% to 58% of sand, while residual clays (K1M and MA2) present on average 12% of clay, 51% of silt and 37% of sand. Two raw clays (KB3 and MA2) can be used for bricks/tiles production without beneficiation or addition. K1M requires some flux addition to decrease the sintering temperature while KG3 presents poor properties due to the combined occurrence of smectite and a high clayey fraction (37%). Such mineralogical composition is responsible for very high plasticity (PI: 50), high shrinkage (LS: 5% - 16%), low porosity (OP: up to 21%) and high flexural strength (FS: 16 - 23 N/mm2) above 1050°C. This last clay is therefore less appropriate for bricks and roofing tiles production since degreasers must be added to the raw material.
文摘The effect of compositions of saw dust admixture on thermal conductivity and other mechanical/refractory properties of Ifon Clay was investigated. The raw clay gotten from Ifon in Ondo state was first processed to very fine particles and characterized using SEM/EDX, XRD and XRF. Sawdust from mahogany tree procured from a saw mill in Akure the State capital of Ondo State was also dried to remove moisture present. A composite mixture of this dried saw dust with the processed clay was made at various proportions of the saw dust, with a little addition of water for plasticity. Sam- ples of cylindrical dimensions were then produced from the mounting press by the process of compaction with a very high pressure. The samples were dried and then finally fired in the furnace at 1000?C for a final curing. Properties which include thermal shock resistance, bulk density, cold crushing strength, thermal conductivity and porosity were obtained by the appropriate standard test methods. The microstructures of the fired samples were also characterized with SEM using back scattered secondary imaging. The results show that the amount of sawdust admixture affects the properties variously;porosity increases with percentage increase in sawdust admixture while the thermal conductivity and other properties of the sample reduce with percentage increase in sawdust admixture. It was concluded that for structural insulating bricks where compressive strength is important the sawdust admixture should not exceed 10 to 15 percent.
