To solve soil shortage in reclaiming subsided land of coal mines, the principal chemical properties of artificial soil formed by mixing organic furfural residue and inorganic fly ash were examined. The results indicat...To solve soil shortage in reclaiming subsided land of coal mines, the principal chemical properties of artificial soil formed by mixing organic furfural residue and inorganic fly ash were examined. The results indicated that the artificial soil was suitable for agriculture use after irrigation and desalination, the available nutrients in the artificial soil could satisfy the growth demand of plants, and the pH tended to the neutrality.展开更多
The focus of this study is to critically review the physiochemical and engineering properties of the fly ash and its applications in various fields.The utilization of fly ash has become a widespread area,but the amoun...The focus of this study is to critically review the physiochemical and engineering properties of the fly ash and its applications in various fields.The utilization of fly ash has become a widespread area,but the amount of utilization is still a serious issue.It has many beneficial qualities(such as pozzolanic property,fineness,spherical shape,lightweight,etc.),which enhance its properties and make it suitable for its utilization as a new construction material.For the bulk utilization of fly ash,it should be employed in the areas independent of any other parameters.So that,the disposal problem can be reduced significantly.The knowledge of its physiochemical characteristic helps in the judgment of appropriate fly ash for any particular type of work.Fly ash can be utilized in other areas such as asphalt concrete,geopolymer concrete,ground improvement,agricultural sector,roller compacted concrete,brick,etc.that will reduce the existing ashes,and also the disposal problem can be solved appreciably.The implementation of fly ash must be avoided below the natural ground water level and below 4°C temperature conditions.展开更多
In the cemented paste backfill(CPB)method,which can also be used for fortification purposes in mines,different additive materials with pozzolanic properties can be employed as substitutes instead of cement that is the...In the cemented paste backfill(CPB)method,which can also be used for fortification purposes in mines,different additive materials with pozzolanic properties can be employed as substitutes instead of cement that is the main binder.One of the most popular pozzolanic materials that can be employed instead of cement is fly ash,which is thermal power plant tailings.But the compositions of fly ash and tailings used in high amounts in the CPB method,as well as the chemical structures that these materials form by interacting with the cement binder,affect the mechanical properties of the material depending on time.In this study,fly ash with 4 different chemical compositions(TFA,SFA,YFA,and CFA)was used as a cement substitute in CPB.By substituting fly ash with different chemical compositions in different proportions,CPB samples were created and their strength was elucidated according to 28,56,and 90-day curing times.The results of the study revealed that TFA with the highest CaO/SiO_(2) and SO_(3) ratios remained stable at the strength values of 6 MPa(total 9% binder)and 10 MPa(total 11% binder)in the long term.However,CFA with the lowest CaO/SiO_(2),SO_(3),and the highest SiO_(2)+Al_(2)O_(3)+Fe_(2)O_(3) ratios resulted in the greatest strength increase at a 20%substitution rate(11% of the total binder).Nevertheless,it was found that the SFA,which is in Class F,increased its strength in the early period based on the CaO rate.展开更多
Fly Ash Cenospheres(FACs)are obtained from the coal power plants in the form of hollow spherical particles by burning the coal.FAC was started to use in early 1980-1985 as lightweight filler material in producing comp...Fly Ash Cenospheres(FACs)are obtained from the coal power plants in the form of hollow spherical particles by burning the coal.FAC was started to use in early 1980-1985 as lightweight filler material in producing composites of cementitious and at present many researchers are focusing on use of FAC as filler in polymer and metals.In this paper,the systematic review on research activities and application of FAC in manufacturing light weight products are done.The influence of FAC on the physical and mechanical properties of incorporated polymer and alloy-based composites were summarized.Prospects of future for its use were also suggested and summarized in this paper.展开更多
The rapidly increasing demand for energy in China leads to the construction of new power plants all over the country. Coal, as the main fuel resource of those power plants, results in increasing problems with the disp...The rapidly increasing demand for energy in China leads to the construction of new power plants all over the country. Coal, as the main fuel resource of those power plants, results in increasing problems with the disposal of solid residues from combustion and off gas cleaning. This investigation describes chances for the utilization of fly ash from coal-fired power plants in China. After briefly comparing the situation in China and Germany, the status of aluminum recycling from fly ash and the ad- vantages for using fly ash in concrete products are introduced. Chemical and physical analyses of Chinese fly ash samples, e.g., X-ray diffraction (XRD), ICP (Inductive Coupled Plasma) and particle size analysis, water requirement, etc. are presented. Rea- sonable amounts of aluminum were detected in the samples under investigation, but for recovery only sophisticated procedures are available up to now. Therefore, simpler techniques are suggested for the first steps in the utilization of Chinese fly ash.展开更多
For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass co...For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of（K） were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO3-4was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were： mass median diameter 4.3 ± 0.8 μm, spread of particle size distribution19 ± 11, particle density 2620 ± 80 kg/m^3 and angle of repose 50°± 1°. The density of the straw fly ashes is lower（2260 ± 80 kg/m^3） and the spread of the size distribution is higher（72 ± 24）.For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller,surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.展开更多
文摘To solve soil shortage in reclaiming subsided land of coal mines, the principal chemical properties of artificial soil formed by mixing organic furfural residue and inorganic fly ash were examined. The results indicated that the artificial soil was suitable for agriculture use after irrigation and desalination, the available nutrients in the artificial soil could satisfy the growth demand of plants, and the pH tended to the neutrality.
基金Science and Engineering Research Board(ECR/2015/000580).
文摘The focus of this study is to critically review the physiochemical and engineering properties of the fly ash and its applications in various fields.The utilization of fly ash has become a widespread area,but the amount of utilization is still a serious issue.It has many beneficial qualities(such as pozzolanic property,fineness,spherical shape,lightweight,etc.),which enhance its properties and make it suitable for its utilization as a new construction material.For the bulk utilization of fly ash,it should be employed in the areas independent of any other parameters.So that,the disposal problem can be reduced significantly.The knowledge of its physiochemical characteristic helps in the judgment of appropriate fly ash for any particular type of work.Fly ash can be utilized in other areas such as asphalt concrete,geopolymer concrete,ground improvement,agricultural sector,roller compacted concrete,brick,etc.that will reduce the existing ashes,and also the disposal problem can be solved appreciably.The implementation of fly ash must be avoided below the natural ground water level and below 4°C temperature conditions.
文摘In the cemented paste backfill(CPB)method,which can also be used for fortification purposes in mines,different additive materials with pozzolanic properties can be employed as substitutes instead of cement that is the main binder.One of the most popular pozzolanic materials that can be employed instead of cement is fly ash,which is thermal power plant tailings.But the compositions of fly ash and tailings used in high amounts in the CPB method,as well as the chemical structures that these materials form by interacting with the cement binder,affect the mechanical properties of the material depending on time.In this study,fly ash with 4 different chemical compositions(TFA,SFA,YFA,and CFA)was used as a cement substitute in CPB.By substituting fly ash with different chemical compositions in different proportions,CPB samples were created and their strength was elucidated according to 28,56,and 90-day curing times.The results of the study revealed that TFA with the highest CaO/SiO_(2) and SO_(3) ratios remained stable at the strength values of 6 MPa(total 9% binder)and 10 MPa(total 11% binder)in the long term.However,CFA with the lowest CaO/SiO_(2),SO_(3),and the highest SiO_(2)+Al_(2)O_(3)+Fe_(2)O_(3) ratios resulted in the greatest strength increase at a 20%substitution rate(11% of the total binder).Nevertheless,it was found that the SFA,which is in Class F,increased its strength in the early period based on the CaO rate.
文摘Fly Ash Cenospheres(FACs)are obtained from the coal power plants in the form of hollow spherical particles by burning the coal.FAC was started to use in early 1980-1985 as lightweight filler material in producing composites of cementitious and at present many researchers are focusing on use of FAC as filler in polymer and metals.In this paper,the systematic review on research activities and application of FAC in manufacturing light weight products are done.The influence of FAC on the physical and mechanical properties of incorporated polymer and alloy-based composites were summarized.Prospects of future for its use were also suggested and summarized in this paper.
文摘The rapidly increasing demand for energy in China leads to the construction of new power plants all over the country. Coal, as the main fuel resource of those power plants, results in increasing problems with the disposal of solid residues from combustion and off gas cleaning. This investigation describes chances for the utilization of fly ash from coal-fired power plants in China. After briefly comparing the situation in China and Germany, the status of aluminum recycling from fly ash and the ad- vantages for using fly ash in concrete products are introduced. Chemical and physical analyses of Chinese fly ash samples, e.g., X-ray diffraction (XRD), ICP (Inductive Coupled Plasma) and particle size analysis, water requirement, etc. are presented. Rea- sonable amounts of aluminum were detected in the samples under investigation, but for recovery only sophisticated procedures are available up to now. Therefore, simpler techniques are suggested for the first steps in the utilization of Chinese fly ash.
文摘For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of（K） were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO3-4was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were： mass median diameter 4.3 ± 0.8 μm, spread of particle size distribution19 ± 11, particle density 2620 ± 80 kg/m^3 and angle of repose 50°± 1°. The density of the straw fly ashes is lower（2260 ± 80 kg/m^3） and the spread of the size distribution is higher（72 ± 24）.For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller,surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.
