Pulverized fly ash (PFA) is produced about 500 billions tons every year in the world in a result of coals combustion. Most of the fly ash collected in power plants is disposed by deposition in landfills, situated as a...Pulverized fly ash (PFA) is produced about 500 billions tons every year in the world in a result of coals combustion. Most of the fly ash collected in power plants is disposed by deposition in landfills, situated as a rule near big cities with well developed infrastructure and high cost of land. Moreover, the pollution of environmental by fine solid wastes is inevitable and takes place in area of residing of a basic part of the population. The only solution is a complex processing of fine wastes with a production of value added materials. New conception of complex processing of PFA is proposed on the base of facilities of Electro-mass-classifier (EMC) and other techniques. The characterization of separated fractions was carried out by SEM and optic microscopy, XRD, laser diffraction, M?ssbauer spectroscopy and other methods. A fine fraction of glass microspheres presents the main interest as filler in various materials.展开更多
Low-grade fly ash (rejected fly ash,rFA),a significant portion of the pulverized fuel ash (PFA) produced from coal-fired power plants and rejected from the ash classifying process,remains unused due to its high carbon...Low-grade fly ash (rejected fly ash,rFA),a significant portion of the pulverized fuel ash (PFA) produced from coal-fired power plants and rejected from the ash classifying process,remains unused due to its high carbon content and large particle size (>45μm).But it is thought that the rejected ash may have potential uses in chemical stabilization/solidification (S/S) processes which need relatively lower strengths and a lower chemical reactivity.Flue Gas Desulphurisation (FGD) sludge is a by-product of air pollution control equipment in coal fired power plants whose chemical composition is mainly gypsum.As there is no effective usage of both of these two materials,it is of interest to research on the possible activation of rFA using FGD.This paper presents experimental results of a study on the properties of rFA activated by the FGD in rFA-cement pastes.Different percentages of FGD were added into the mix to study the effects of the FGD on the reaction of the rFA blended cement pastes.The results show that FGD takes effect as an activator only at late curing ages.Adding Ca(OH) 2 enhances the effect of FGD on activating the hydration of rFA.Also,10% FGD by weight of rFA is the optimal addition in the rFA-cement pastes.The results of the compressive strength measurements correlate well with the porosity results.展开更多
文摘Pulverized fly ash (PFA) is produced about 500 billions tons every year in the world in a result of coals combustion. Most of the fly ash collected in power plants is disposed by deposition in landfills, situated as a rule near big cities with well developed infrastructure and high cost of land. Moreover, the pollution of environmental by fine solid wastes is inevitable and takes place in area of residing of a basic part of the population. The only solution is a complex processing of fine wastes with a production of value added materials. New conception of complex processing of PFA is proposed on the base of facilities of Electro-mass-classifier (EMC) and other techniques. The characterization of separated fractions was carried out by SEM and optic microscopy, XRD, laser diffraction, M?ssbauer spectroscopy and other methods. A fine fraction of glass microspheres presents the main interest as filler in various materials.
文摘Low-grade fly ash (rejected fly ash,rFA),a significant portion of the pulverized fuel ash (PFA) produced from coal-fired power plants and rejected from the ash classifying process,remains unused due to its high carbon content and large particle size (>45μm).But it is thought that the rejected ash may have potential uses in chemical stabilization/solidification (S/S) processes which need relatively lower strengths and a lower chemical reactivity.Flue Gas Desulphurisation (FGD) sludge is a by-product of air pollution control equipment in coal fired power plants whose chemical composition is mainly gypsum.As there is no effective usage of both of these two materials,it is of interest to research on the possible activation of rFA using FGD.This paper presents experimental results of a study on the properties of rFA activated by the FGD in rFA-cement pastes.Different percentages of FGD were added into the mix to study the effects of the FGD on the reaction of the rFA blended cement pastes.The results show that FGD takes effect as an activator only at late curing ages.Adding Ca(OH) 2 enhances the effect of FGD on activating the hydration of rFA.Also,10% FGD by weight of rFA is the optimal addition in the rFA-cement pastes.The results of the compressive strength measurements correlate well with the porosity results.
