Method for removal of unburned carbon in fly ash

Abstract

The object is to remove unburned carbon in a fly ash in a stable and economically advantageous manner. A fly ash, water and a trapping agent are mixed together in a hybrid mixer (2), a shearing force is applied to the mixture to prepare a slurry containing surface-modified unburned carbon within a short time, a foaming agent is added to the slurry, and then the unburned carbon is separated by performing flotation separation in a flotator (11).

Description

technical field [0001] The present invention relates to a method for removing unburned carbon in fly ash, and particularly relates to a method for removing unburned carbon contained in fly ash discharged from coal-fired power plants and the like. Background technique [0002] Coal can be used stably over a long period of time as an energy source with confirmed recoverable reserves of more than 200 years. Therefore, the proportion of coal thermal power generation is increasing year by year, and the production of coal ash (hereinafter referred to as "fly ash") is expected to further increase in the future. [0003] Under such circumstances, it is necessary to effectively utilize fly ash in large quantities from the viewpoint of environmental protection and effective utilization of resources. [0004] At present, fly ash is used as a cement admixture after removing unburned carbon. By improving the removal rate of this unburned carbon and improving the quality of fly ash, its u...

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Problems solved by technology

[0008] Specifically, there is the following problem: in the mixing tank 62 shown in FIG. 9, if fly ash 87 and water 88 are to be stirred to generate slurry 89, fly ash 87 will adhere around the rotating shaft 81 of the stirring blade 82 and cannot In addition, the water or water vapor in the mixing tank 52 wets the fly ash 87 and blocks the fly ash supply pipe 84

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