CN111999138B - Fly ash grading and heavy metal scale distribution analysis method and device - Google Patents

Fly ash grading and heavy metal scale distribution analysis method and device Download PDF

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CN111999138B
CN111999138B CN202010676644.8A CN202010676644A CN111999138B CN 111999138 B CN111999138 B CN 111999138B CN 202010676644 A CN202010676644 A CN 202010676644A CN 111999138 B CN111999138 B CN 111999138B
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fly ash
heavy metal
particles
size distribution
particle size
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CN111999138A (en
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胡红云
龚泓宇
姚洪
付彪
黄永达
李帅
罗光前
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Huazhong University of Science and Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00—Magnetic separation
    • B03C1/02—Magnetic separation acting directly on the substance being separated
    • B03C1/30—Combinations with other devices, not otherwise provided for
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
    • B04C9/00—Combinations with other devices, e.g. fans, expansion chambers, diffusors, water locks
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/34—Purifying; Cleaning
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/38—Diluting, dispersing or mixing samples
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/02—Investigating particle size or size distribution
    • G01N15/0272—Investigating particle size or size distribution with screening; with classification by filtering
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/38—Diluting, dispersing or mixing samples
    • G01N2001/386—Other diluting or mixing processes
    • G01N2001/387—Other diluting or mixing processes mixing by blowing a gas, bubbling

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Abstract

The invention belongs to the field of combustion pollutant detection, and particularly discloses a method and a device for classifying fly ash and analyzing heavy metal scale distribution. The method comprises the following steps: primarily screening the fly ash to obtain the fly ash with the particle size of less than 100 mu m; adding a Fe-based dispersing agent into the screened fly ash, and uniformly mixing the fly ash by utilizing the heated carrier gas to obtain mixed particles; separating the mixed particles, and separating out the mixed particles with the particle size of more than 10 mu m; grading the mixed particles with the particle size of less than 10 mu m to obtain the size distribution characteristic of the fly ash, and then analyzing the heavy metal content of each grade of fly ash to further obtain the size distribution characteristic of the heavy metal. The invention utilizes the Fe-based dispersing agent to reduce the electrostatic interaction among the fly ash particles and simultaneously reduce the adhesive force and the cohesive force among the particles, thereby promoting the dispersion of the fly ash; in addition, the heated carrier gas is used for weakening the acting force among particles, so that the accuracy of fly ash classification and heavy metal scale distribution analysis is effectively improved.

Description

Fly ash grading and heavy metal scale distribution analysis method and device
Technical Field
The invention belongs to the field of combustion pollutant detection, and particularly relates to a method and a device for classifying fly ash and analyzing heavy metal size distribution.
Background
Thermal power generation is a main power generation mode in China, and SO is removed along with release of a large amount of pollutants in the fuel combustion process2、NOxIn addition to conventional pollutants, the release of heavy metal pollutants has also attracted a great deal of attention. Under the high-temperature environment of combustion, part of heavy metal elements can be released in a gaseous state and then transferred to fly ash particles, and most of the particles can be captured by the dust removal device. However, the existence of the escape window of the dust removal device can cause the particles with the particle size of 0.1-1 μm to escape more easily, and the fine particles are easy to enrich heavy metal elements. Heavy metals discharged into the atmosphere can directly enter the human body or the animal body through the respiratory tract, and damage the respiratory system, the digestive system, the nervous system and the like. Therefore, the distribution characteristics of heavy metals on the fly ash with different scales directly influence the trapping effect of the dust removal device, and in order to strengthen the cooperative removal of the heavy metals and particles, the scale distribution of the heavy metals is explored, and the development of the fly ash classification technology is particularly important.
CN201810452965.2 discloses a boiler fly ash particle grading sampler, in which a grading device extracts flue gas from a flue, and directly grades particulate matters in the flue gas by using the action of a multi-stage filter screen, so that collected ash sample components are closer to fly ash components in the flue, but the method grades fly ash by using the filter screen, which cannot satisfy analysis of heavy metal content on ultrafine particulate matters, and the collection process causes loss of ash sample, and has a large influence on analysis of heavy metal content; CN200410066002.7 discloses a fluidized bed dry type aerosol generating method and an aerosol generator, which utilize the fluidization state characteristics of solid particles to pulverize and aerosolize powdery multi-particle polymer mixed in a bed material into single particles, and then can measure the concentration and particle size of the generated aerosol, but in the method, the flying ash particles may be broken, and the size distribution of the flying ash particles is affected.
Disclosure of Invention
In view of the above-mentioned disadvantages and/or needs for improvement in the prior art, the present invention provides a method and an apparatus for analyzing fly ash classification and heavy metal size distribution, wherein the method utilizes a Fe-based dispersant to reduce fly ash agglomeration and promote fly ash dispersion, and utilizes a heated carrier gas to weaken the adhesion between particles and further promote fly ash dispersion, thereby effectively improving the accuracy of fly ash classification and heavy metal size distribution analysis.
To achieve the above object, according to one aspect of the present invention, there is provided a fly ash classification and heavy metal size distribution analysis method, comprising the steps of:
s1, carrying out primary screening on the fly ash to obtain the fly ash with the particle size of less than 100 mu m;
s2, adding a Fe-based dispersing agent into the screened fly ash, and uniformly mixing the fly ash with the heated carrier gas to obtain mixed particles;
s3, separating the mixed particles, and separating the mixed particles with the particle size of more than 10 mu m;
s4, carrying out grading treatment on the mixed particles with the particle size of less than 10 μm to obtain the size distribution characteristic of the fly ash, and then carrying out heavy metal content analysis on each level of fly ash to further obtain the size distribution characteristic of the heavy metal.
As a further preferred, the fly ash classification and heavy metal scale analysis method further comprises the following steps:
s5, taking another part of fly ash to carry out primary screening to obtain fly ash with the particle size less than 100 mu m, then adding standard particles into the screened fly ash and repeating the steps S2-S4 to obtain the fly ash size distribution characteristic added with the standard particles, and the fly ash size distribution characteristic is used for verifying the accuracy of the fly ash size distribution characteristic obtained in the step S4.
Further preferably, the mixed particles with the particle size of more than 10 μm obtained in step S3 are subjected to magnetic separation, thereby realizing the recycling of the Fe-based dispersing agent.
As a further preferred, the fly ash is coal burning fly ash, refuse incineration fly ash or biomass incineration fly ash.
More preferably, the addition proportion of the Fe-based dispersing agent is 0.5-2% of the mass of the fly ash; the grain diameter of the Fe-based dispersing agent is 20-40 mu m.
More preferably, the temperature of the carrier gas is 40 to 60 ℃.
More preferably, the standard particulate matter is polystyrene spherical particles, and the addition proportion of the standard particulate matter is 0.5-1% of the mass of the fly ash.
According to another aspect of the present invention, there is provided a fly ash classification and heavy metal size distribution analysis apparatus, comprising a feeding module, a screening module and a testing module, wherein:
the feeding module comprises a vibrating screen, a feeder and an air supply mechanism, wherein the vibrating screen is connected with the feeder and is used for primarily screening the fly ash to obtain the fly ash with the particle size of less than 100 mu m and sending the fly ash into the feeder; while the feeder is also used to place Fe-based dispersant; the air supply mechanism is used for supplying heated carrier gas so as to send the screened fly ash and the Fe-based dispersing agent in the feeder into the screening module;
the screening module comprises a mixing chamber, a cyclone separator and a fly ash grading mechanism, wherein the inlet of the mixing chamber is connected with the outlets of the feeder and the air supply mechanism and is used for uniformly mixing the Fe-based dispersant and the screened fly ash to obtain mixed particles, the outlet of the mixing chamber is connected with the cyclone separator so as to send the mixed particles into the cyclone separator for separation to obtain mixed particles with the particle size of more than 10 mu m and mixed particles with the particle size of less than 10 mu m, and the mixed particles with the particle size of less than 10 mu m are sent into the fly ash grading mechanism for grading treatment to obtain the scale distribution characteristic of the fly ash;
the test module is used for analyzing the heavy metal content of the fly ash after the grading treatment so as to obtain the heavy metal scale distribution characteristic.
As a further preference, the feeder is also used for placing standard particulate matter to obtain the fly ash size distribution characteristics after adding the standard particulate matter, thereby verifying the accuracy of the original fly ash size distribution characteristics.
As a further preference, the fly ash classification mechanism is an ELPI charged low-pressure particulate impactor, an LPI low-pressure impactor or an anderson eight-stage impactor.
Generally, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:
1. the invention provides a method for analyzing grading of fly ash and size distribution of heavy metals, which can effectively reduce the influence of fly ash aggregates on size analysis, wherein the fly ash is mixed with a Fe-based dispersing agent, the electrostatic charge accumulated by fly ash particles is reduced by utilizing the conductivity of the Fe-based dispersing agent, and the electrostatic action among the fly ash particles is further reduced; meanwhile, after the Fe-based dispersing agent is added, the collision among the fly ash particles is reduced, and the adhesive force and the cohesive force among the particles are reduced, so that the fly ash dispersion is promoted; in addition, due to the moisture absorption effect of the fly ash particles, the water on the surfaces of the particles can greatly increase the adhesive force among the particles, and the heated carrier gas is used for mixing the particles, so that the acting force among the particles can be effectively weakened, the fly ash dispersion is further promoted, and the accuracy of the fly ash classification and the heavy metal scale distribution analysis is further effectively improved;
2. in addition, the recovery rate of the standard substance is obtained by comparing the fly ash scale distribution difference obtained before and after the addition of the standard particulate matter, the accuracy of the grading result can be verified, the fly ash scale distribution obtained in each experiment and the actual fly ash scale distribution are obtained, and the accurate heavy metal scale distribution characteristic is further obtained;
3. the invention also provides a device for analyzing the grading of the fly ash and the size distribution of the heavy metal, which utilizes the Fe-based dispersing agent and the heated carrier gas to disperse the fly ash particles to obtain mixed particles, simultaneously utilizes the mixing chamber to provide a space for buffering, diffusing and mixing for the mixed particles, can simulate the environment of flue sampling as much as possible, reduces the flow velocity of fluid by adjusting the size of the mixing chamber, can effectively inhibit air flow turbulence, reduces the influence of fly ash agglomeration on the analysis of the size distribution of the heavy metal, and ensures that the size distribution of the obtained heavy metal is close to the actual size distribution.
Drawings
Fig. 1 is a schematic structural diagram of a fly ash classification and heavy metal size distribution analysis apparatus according to a preferred embodiment of the present invention.
The same reference numbers will be used throughout the drawings to refer to the same elements or structures, wherein:
1-a first blower, 2-a first filter, 3-a first heater, 4-a nozzle, 5-a dispersing brush, 6-a feeder, 7-a vibrating screen, 8-a second blower, 9-a mixing chamber, 10-a cyclone separator, 11-a vacuum pump, 12-a fly ash grading mechanism, 13-a testing module, 14-a second filter and 15-a second heater.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in fig. 1, an embodiment of the present invention provides a fly ash classification and heavy metal size distribution analysis method, which includes the following steps:
s1, primarily screening the fly ash by using a vibrating screen 7 to obtain fly ash with the particle size of less than 100 microns, and sending the fly ash into a feeder 6, wherein the fly ash is coal-fired fly ash, waste incineration fly ash or biomass incineration fly ash;
s2, adding Fe-based dispersing agent into the screened fly ash, mixing and quantitatively conveying the fly ash to a nozzle 4 through a dispersing brush 5, reducing the electrostatic action among fly ash particles by utilizing the conductivity of the Fe-based dispersing agent to promote the dispersion of the fly ash particles, then sending the fly ash particles into a mixing chamber 9 by utilizing heated carrier gas to be further uniformly mixed to obtain mixed particles, reducing the moisture on the surfaces of the particles by utilizing the temperature of the carrier gas to further weaken the adhesive force among the particles and promote the dispersion of the fly ash, and on the other hand, further promoting the dispersion of the fly ash by utilizing the buffer diffusion and mixing action of the mixing chamber 9 and reducing the influence of fly ash agglomeration on the size distribution;
s3, separating the mixed particles by using a cyclone separator, separating the mixed particles with the particle size of more than 10 mu m, and performing magnetic separation on the mixed particles so as to recover and reuse the Fe-based dispersing agent;
s4, because the grain sizes of the Fe-based dispersing agents are all larger than 10 microns, the mixed particles with the grain sizes smaller than 10 microns are all fly ash, the mixed particles with the grain sizes smaller than 10 microns are subjected to grading treatment, so that the fly ash scale distribution characteristic is obtained, and then heavy metal content analysis is carried out on each level of fly ash, so that the heavy metal scale distribution characteristic is obtained;
s5, taking another part of fly ash to carry out primary screening to obtain fly ash with the particle size less than 100 mu m, then adding standard particles into the screened fly ash and repeating the steps S2-S4 to obtain the fly ash size distribution characteristic added with the standard particles, and the fly ash size distribution characteristic is used for verifying the accuracy of the fly ash size distribution characteristic obtained in the step S4.
Furthermore, the addition proportion of the Fe-based dispersing agent is 0.5-2% of the mass of the fly ash, and the particle size of the Fe-based dispersing agent is 20-40 μm, so that the acting force among fly ash particles is weakened to the maximum extent, the fly ash dispersion is promoted, and the increase of the inter-particle resistance caused by overhigh addition proportion is avoided.
Furthermore, the temperature of the heated carrier gas is 40-60 ℃, thereby ensuring that the moisture on the surface of the fly ash is fully evaporated, reducing the adhesive force among fly ash particles, promoting the dispersion of the fly ash, and avoiding the increase of the acting force among the fly ash particles due to the enhancement of the electrostatic action caused by overhigh temperature.
Furthermore, the standard particulate matters are spherical polystyrene particles, the spherical polystyrene particles do not contain heavy metals, the detection result of the heavy metal scale distribution characteristic of the fly ash is not influenced, and the addition proportion of the standard particulate matters is 0.5-1% of the mass of the fly ash, so that the accuracy of the classification of the fly ash is verified under the condition that the analysis of the heavy metal content of the fly ash below 10 microns is not influenced.
According to another aspect of the present invention, there is provided a fly ash classification and heavy metal size distribution analysis apparatus, comprising a feeding module, a screening module and a testing module, wherein:
the feeding module comprises a vibrating screen 7, a feeder 6 and an air supply mechanism, wherein the vibrating screen 7 is connected with the feeder 6 and is used for primarily screening the fly ash to obtain the fly ash with the particle size of less than 100 mu m and sending the fly ash into the feeder 6; meanwhile, the feeder 6 is also used for placing Fe-based dispersing agent, the screened fly ash and the Fe-based dispersing agent are quantitatively conveyed to a nozzle through a dispersing brush 5 after being mixed in the feeder 6, and are conveyed to a screening module under the action of heated carrier gas generated by a first blower 1, a first filter 2 and a first heater 3 which are connected in sequence in an air supply mechanism; meanwhile, the air supply mechanism also comprises a second air supply blower 8, a second filter 14 and a second heater 15, and the generated heated carrier gas is directly introduced into the mixing chamber 9 and is used for controlling the air volume entering the mixing chamber 9;
the screening module comprises a mixing chamber 9, a cyclone separator 10 and a fly ash grading mechanism 12, wherein the inlet of the mixing chamber 9 is connected with the outlet of the feeder 6 and the outlet of the air supply mechanism and is used for uniformly mixing the Fe-based dispersing agent and the screened fly ash to obtain mixed particles, the outlet of the mixing chamber 9 is connected with the cyclone separator 10 so as to send the mixed particles into the cyclone separator 10 for separation to obtain the mixed particles with the particle size of more than 10 microns and the mixed particles with the particle size of less than 10 microns, and the mixed particles with the particle size of less than 10 microns are sent into the fly ash grading mechanism for grading treatment to obtain the fly ash size distribution characteristic;
the test module 13 is used for analyzing the heavy metal content of the fly ash after the grading treatment, so as to obtain the heavy metal scale distribution characteristic.
Further, the feeder 6 is also used for placing standard particles to obtain the fly ash size distribution characteristic after the standard particles are added, and then the accuracy of the original fly ash size distribution characteristic is verified.
Further, the fly ash grading mechanism is an ELPI charged low-pressure particle impactor, an LPI low-pressure impactor or an Anderson eight-grade impactor, and is connected with the vacuum pump 11 and used for adjusting the inlet flow rate of the impactor and meeting the rated working condition requirement of the impactor.
The present invention will now be described in further detail by taking a specific fly ash classification device and a heavy metal size distribution analysis method as examples.
Example 1
S1, carrying out primary screening on the fly ash to obtain the fly ash with the particle size of less than 100 mu m;
s2, adding 2% of Fe-based dispersing agent (the grain diameter is 20-40 μm) into the screened fly ash, and uniformly mixing the materials by using carrier gas at 45 ℃ to obtain mixed particles;
s3, separating the mixed particles, and separating the mixed particles with the particle size larger than 10 mu m;
s4, carrying out classification treatment on the mixed particles with the particle size of less than 10 μm to obtain the size distribution characteristic of the fly ash, and then carrying out heavy metal content analysis on each level of fly ash to further obtain the size distribution characteristic of the heavy metal;
s5, another part of fly ash is taken to be primarily screened to obtain fly ash with the particle size of less than 100 μm, then 1% of standard particulate matters are added into the screened fly ash, and the steps S2-S4 are repeated to obtain the fly ash scale distribution characteristic after the standard particulate matters are added, the recovery rate of the standard particulate matters reaches 95%, and the fly ash is proved to be more accurate in classification.
Example 2
S1, carrying out primary screening on the fly ash to obtain the fly ash with the particle size of less than 100 mu m;
s2, adding 0.5% of Fe-based dispersing agent into the screened fly ash, and uniformly mixing the materials by using carrier gas at 60 ℃ to obtain mixed particles;
s3, separating the mixed particles, and separating the mixed particles with the particle size larger than 10 mu m;
s4, carrying out classification treatment on the mixed particles with the particle size of less than 10 μm to obtain the size distribution characteristic of the fly ash, and then carrying out heavy metal content analysis on each level of fly ash to further obtain the size distribution characteristic of the heavy metal;
s5, taking the other part of fly ash to carry out primary screening to obtain fly ash with the particle size less than 100 mu m, then adding 0.75% of standard particulate matters into the screened fly ash, and repeating the steps S2-S4 to obtain the fly ash scale distribution characteristic after the standard particulate matters are added, wherein the recovery rate of the standard particulate matters reaches 94%, and the classification of the fly ash is proved to be more accurate.
Example 3
S1, carrying out primary screening on the fly ash to obtain the fly ash with the particle size of less than 100 mu m;
s2, adding 1% of Fe-based dispersing agent into the screened fly ash, and uniformly mixing the materials by using carrier gas at 40 ℃ to obtain mixed particles;
s3, separating the mixed particles, and separating the mixed particles with the particle size larger than 10 mu m;
s4, carrying out classification treatment on the mixed particles with the particle size of less than 10 μm to obtain the size distribution characteristic of the fly ash, and then carrying out heavy metal content analysis on each level of fly ash to further obtain the size distribution characteristic of the heavy metal;
s5, taking the other part of fly ash to carry out primary screening to obtain fly ash with the particle size less than 100 mu m, then adding 0.5% of standard particulate matters into the screened fly ash, and repeating the steps S2-S4 to obtain the fly ash scale distribution characteristic after the standard particulate matters are added, wherein the recovery rate of the standard particulate matters reaches 96%, and the fly ash classification is proved to be more accurate.
It will be understood by those skilled in the art that the foregoing is merely a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included within the scope of the present invention.

Claims (7)

1. A fly ash grading and heavy metal size distribution analysis method is characterized by comprising the following steps:
s1, carrying out primary screening on the fly ash to obtain the fly ash with the particle size of less than 100 mu m;
s2, adding a Fe-based dispersing agent into the screened fly ash, and uniformly mixing the fly ash by using heated carrier gas to obtain mixed particles, wherein the temperature of the carrier gas is 40-60 ℃;
s3, separating the mixed particles, and separating out the mixed particles with the particle size of more than 10 mu m;
s4, carrying out grading treatment on the mixed particles with the particle size of less than 10 mu m to obtain the size distribution characteristic of the fly ash, and then carrying out heavy metal content analysis on each level of fly ash to further obtain the size distribution characteristic of the heavy metal;
s5, taking another part of fly ash to carry out primary screening to obtain fly ash with the particle size less than 100 mu m, then adding standard particles into the screened fly ash and repeating the steps S2-S4 to obtain the fly ash size distribution characteristic added with the standard particles, and the fly ash size distribution characteristic is used for verifying the accuracy of the fly ash size distribution characteristic obtained in the step S4.
2. The fly ash classification and heavy metal size distribution analysis method of claim 1, wherein the mixed particles with the particle size of more than 10 μm obtained in step S3 are subjected to magnetic separation, thereby realizing the recycling of the Fe-based dispersing agent.
3. The fly ash classification and heavy metal size distribution analysis method according to claim 1, wherein the fly ash is coal-fired fly ash, waste incineration fly ash or biomass incineration fly ash.
4. The fly ash classification and heavy metal size distribution analysis method according to claim 1, wherein the addition proportion of the Fe-based dispersant is 0.5% to 2% of the mass of the fly ash; the grain diameter of the Fe-based dispersing agent is 20-40 mu m.
5. The fly ash classification and heavy metal size distribution analysis method according to claim 1, wherein the standard particulate matter is polystyrene spherical particles, and the addition ratio of the standard particulate matter is 0.5-1% of the mass of the fly ash.
6. A fly ash classification and heavy metal size distribution analysis device, characterized in that the device comprises a feeding module, a screening module and a testing module (13), wherein:
the feeding module comprises a vibrating screen (7), a feeder (6) and an air supply mechanism, wherein the vibrating screen (7) is connected with the feeder (6) and is used for primarily screening the fly ash to obtain the fly ash with the particle size of less than 100 mu m and sending the fly ash into the feeder (6); while the feeder (6) is also used for placing Fe-based dispersing agent; the air supply mechanism is used for providing heated carrier gas so as to send the fly ash and the Fe-based dispersing agent screened in the feeder into the screening module;
the screening module comprises a mixing chamber (9), a cyclone separator (10) and a fly ash grading mechanism (12), wherein the inlet of the mixing chamber (9) is connected with the outlets of the feeder (6) and the air supply mechanism and is used for uniformly mixing the Fe-based dispersing agent and screened fly ash to obtain mixed particles, the outlet of the mixing chamber (9) is connected with the cyclone separator (10) so as to send the mixed particles into the cyclone separator (10) for separation to obtain mixed particles with the particle size of more than 10 microns and mixed particles with the particle size of less than 10 microns, and send the mixed particles with the particle size of less than 10 microns into the fly ash grading mechanism for grading treatment to obtain the fly ash size distribution characteristic;
the testing module (13) is used for analyzing the heavy metal content of the fly ash subjected to grading treatment so as to obtain the heavy metal scale distribution characteristic; the feeder (6) is also used for placing standard particles so as to obtain the fly ash size distribution characteristic after the standard particles are added, and further, the accuracy of the original fly ash size distribution characteristic is verified.
7. A fly ash classification and heavy metal size distribution analysis apparatus according to claim 6, wherein the fly ash classification mechanism (12) is an ELPI charged low-pressure particulate impactor, an LPI low-pressure impactor or an Anderson eight-stage impactor.
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