A waste incineration fly ash pretreatment modifier

Abstract

The present application belongs to the technical field of harmless resource disposal of garbage and solid waste, and particularly relates to a garbage incineration fly ash pretreatment modifier. The modifier is composed of more than 90% of cementing material as the strength core, and less than 10% of colorant and solubilizer. The modifier can be mixed with garbage incineration fly ash in gradient proportion, and after water granulation and wet heat curing, homogeneous and strengthened particles are formed, which have the characteristics of "three non-decomposition" of soaking in water, mechanical water washing, high temperature calcination and high temperature rapid cooling. The present application can adapt to the temperature disposal conditions of room temperature-600 DEG C and room temperature-1200 DEG C through differential formula, effectively solves the industry pain points of existing fly ash disposal process, such as pollution overflow, equipment failure, incomplete disposal, low product strength and poor process stability, and has excellent modification effect, wide adaptability, large-scale application, and high environmental and economic value.

Description

Technical Field

[0001] This invention belongs to the field of harmless and resource-based disposal technology of solid waste, specifically relating to a pretreatment modifier for fly ash from waste incineration. Background Technology

[0002] Municipal solid waste incineration for power generation is currently the mainstream technology for the harmless disposal of urban municipal solid waste, with advantages such as volume reduction, harmlessness, and resource recovery. However, the incineration process generates a large amount of fly ash. Fly ash has a complex composition, enriched with highly toxic dioxins, heavy metal ions, and high concentrations of chloride and sulfate salts, and is classified as hazardous solid waste. Improper disposal can cause serious soil, water, and air pollution.

[0003] Currently, the mainstream fly ash treatment process in the industry mainly relies on high-temperature calcination combined with water washing and desalination for resource recovery, supplemented by stabilization and solidification technologies. However, existing processes and supporting modification technologies suffer from several insurmountable technical challenges: First, during high-temperature calcination of salt-containing fly ash, residual chlorides and sulfates in the fly ash easily melt and form scale, leading to ring formation and kiln blockage in the calcination equipment, causing production interruptions and extremely poor process stability. Second, the high-temperature corrosion-resistant materials used in the equipment require high-grade materials, necessitating frequent replacements and resulting in high maintenance costs. Third, high-temperature calcination of fly ash requires high-quality equipment sealing, and the production environment is harsh. Fourth, conventionally modified fly ash particles have low structural strength and poor resistance to water, mechanical erosion, high temperatures, and rapid cooling, making them prone to disintegration during water washing and high-temperature treatment, severely affecting the quality of the resource-recovered products and resulting in substandard product strength. Fifth, existing fly ash modifier formulations are highly homogenized and have limited functions, often only providing single solidification or desalination auxiliary effects, failing to meet the processing needs of all operating conditions from ambient temperature to high temperature, thus limiting their adaptability and practicality.

[0004] In summary, existing technologies for the pretreatment and modification of fly ash from waste incineration suffer from drawbacks such as pollutant leakage, equipment malfunctions, incomplete treatment, poor product performance, weak process stability, and insufficient versatility. There is an urgent need to develop a multifunctional fly ash pretreatment modifier that is adaptable to all operating conditions and has excellent modification effects to solve common technical problems in the industry.

[0005] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventors studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0006] This invention belongs to the field of harmless and resource-based disposal technology of solid waste, specifically relating to a pretreatment modifier for fly ash from waste incineration.

[0007] To address the aforementioned technical problems, one objective of this invention is to provide a waste incineration fly ash pretreatment modifier, comprising, by mass percentage, no more than 10% functional additives and no less than 90% binding materials, wherein the binding materials are one or more of blast furnace slag powder, fly ash, yellow phosphorus slag powder, lithium slag powder, steel slag powder, silica fume, calcined clay, and calcined kaolin; and the functional additives are one or more of colorants and co-solvents.

[0008] According to a preferred embodiment, the fluxing agent is one or more of the following: dolomite, albite, red granite powder, laterite, iron oxide or hydroxide powder, iron ore powder, cuprous oxide, lithium ore powder, wood ash, lithium slag powder, and coal powder.

[0009] According to a preferred embodiment, the colorant is one or more of the following: red granite powder, calcined laterite, iron oxide or hydroxide powder, iron ore powder, potassium feldspar, cuprous oxide, and coal powder.

[0010] One of the objectives of this invention is to provide the use of the above-mentioned waste incineration fly ash pretreatment modifier in the harmless treatment of solid waste.

[0011] According to a preferred embodiment, the fly ash from waste incineration is dry ash from a waste-to-energy plant that has not undergone chelation treatment.

[0012] According to a preferred embodiment, by weight fraction, 80 parts of waste incineration fly ash pretreatment modifier are prepared for every 100 parts of waste incineration fly ash.

[0013] One of the objectives of this invention is to provide a method for using a pretreatment modifier for waste incineration fly ash, which includes the following steps: By weight fraction, for every 100 parts of waste incineration fly ash, add 30-80 parts of the aforementioned waste incineration fly ash pretreatment modifier, and mix in 8-20% water by weight of the total powder, then perform fly ash treatment. Grayish-white powder (corresponding to potassium feldspar, dolomite, and sodium feldspar) and black powder (corresponding to magnetite powder, coal powder, and wood ash) are suitable for medium and low temperature fly ash treatment from room temperature to 600℃. Red (corresponding to ferric oxide, ferric hydroxide, or limonite derivatives), yellow (corresponding to ferrous oxide or ferrous hydroxide), and green (cuprous oxide) powders are suitable for fly ash treatment at temperatures ranging from room temperature to 1200℃.

[0014] Preferably, grayish-white and black powders are suitable for medium-low temperature fly ash treatment at 600℃. Red, yellow, and green powders are suitable for high-temperature fly ash treatment at 1200℃.

[0015] According to a preferred embodiment, by weight fraction, 30 parts of the above-mentioned waste incineration fly ash pretreatment modifier are added to 100 parts of waste incineration fly ash. Alternatively, by weight fraction, 40 parts of the above-mentioned waste incineration fly ash pretreatment modifier are added to 100 parts of waste incineration fly ash. Alternatively, by weight fraction, 50 parts of the above-mentioned waste incineration fly ash pretreatment modifier are added to 100 parts of waste incineration fly ash. Alternatively, by weight fraction, 60 parts of the above-mentioned waste incineration fly ash pretreatment modifier are added to 100 parts of waste incineration fly ash. Alternatively, by weight fraction, 70 parts of the above-mentioned waste incineration fly ash pretreatment modifier are added to 100 parts of waste incineration fly ash. Alternatively, by weight fraction, 80 parts of the above-mentioned waste incineration fly ash pretreatment modifier are added to 100 parts of waste incineration fly ash.

[0016] According to a preferred embodiment, water is added at 8% of the total mass of the powder. Water is added at 11% of the total mass of the powder. Water is added at 13% of the total mass of the powder. Water is added at 15% of the total mass of the powder.

[0017] According to a preferred embodiment, the fly ash treatment time is 6 to 48 hours. Preferably, the fly ash treatment time is 6 hours. Preferably, the fly ash treatment time is 36 hours. Preferably, the fly ash treatment time is 48 hours.

[0018] According to a preferred embodiment, before fly ash treatment, the mixture is compressed into particles of 1-5 mm. Preferably, the mixture is compressed into particles of 1 mm. The mixture is also compressed into particles of 2 mm, 3 mm, 4 mm, or 5 mm.

[0019] According to a preferred embodiment, the fly ash-treated particles do not crack when calcined at a high temperature of 400~1200℃; the fly ash-treated particles do not break when immersed in room temperature water at a high temperature of 800℃.

[0020] The beneficial effects of this technical solution are: 1. Achieving the core performance of "three no-decay" in fly ash particles, with extremely high stability. The modifier of this invention forms a dense and stable three-dimensional network structure inside the fly ash particles through hydration and curing of the cementing material. The modified particles have excellent characteristics such as not disintegrating after long-term water immersion, not being damaged by mechanical water washing, not cracking after high-temperature calcination at 400~1200℃, and maintaining structural integrity without damage after direct immersion in water and rapid cooling at 800℃. This completely solves the problems of easy disintegration and poor tolerance of traditional fly ash particles, and significantly improves the strength and qualification rate of resource-based products.

[0021] 2. This invention prevents the leakage of pollutants during washing and purifies the wash brine. During the granulation and compaction process, the activated carbon loaded with pre-adsorbed dioxins and heavy metals from fly ash, along with unburned solid organic matter, is completely encapsulated within the granules. This prevents pollutants from precipitating and leaking out during the washing and desalination process, resulting in a clear wash brine free of colored impurities, containing only a small amount of the inherent white flocculent leaching from fly ash. This significantly reduces the difficulty and cost of subsequent wash brine treatment.

[0022] 3. Solving the problem of ring formation and kiln blockage in high-temperature calcination equipment. The compounded fluxing components of this invention can optimize the high-temperature sintering characteristics of fly ash, reduce the risk of chloride and sulfate melting and scaling, avoid ring formation and kiln blockage failures under high-temperature conditions, ensure continuous and stable operation of the production line, and improve process stability and production efficiency.

[0023] 4. Adaptable to all temperature ranges and highly versatile. This invention controls the color of four powders through differentiated formulations, corresponding to different temperature processing processes. Grayish-white and black powders are suitable for medium and low temperature treatments at 600℃ and below, while red and yellow powders are suitable for high temperature treatments at 1200℃ and below. This can comprehensively cover the entire process of fly ash stabilization, desalination, calcination, and resource recovery.

[0024] 5. Synergistic treatment of multiple pollutants for thorough harmlessness. Through the synergistic effect of physical encapsulation and solidification combined with chemical stabilization, dioxins are sealed and blocked, and heavy metals are fixed and passivated, preventing heavy metal leaching and dioxin diffusion. The harmlessness treatment effect far exceeds that of traditional single modification technologies.

[0025] 6. Wide process adaptability and simple operation. The modifier of this invention is in powder form, which has good mixing uniformity with fly ash. It can be adapted to gradient ratio and gradient granulation particle size requirements. The curing process is simple. After modification, the particles are stable in color and have no performance degradation after water washing, high temperature and water quenching treatment. It can be promoted and applied on a large scale.

[0026] 7. By using a cement-free modifier, the sulfate mineral components in fly ash are transformed, while the particle strength is enhanced. The activated carbon loaded with dioxins and heavy metals originally adsorbed in the fly ash, as well as the unburned solid organic matter, are completely encapsulated inside the particles. During the water washing and desalination process, pollutants cannot be released or leaked out. The final wash brine is clear and free of colored impurities, containing only a small amount of the white flocculent leaching inherent in fly ash. This significantly reduces the difficulty and cost of subsequent wash brine treatment. It also increases the melting temperature of the particles, solving the problem of melting and ring formation during high-temperature treatment of fly ash. At the same time, it achieves the core performance of "three non-rotten" particles, forming a synergistic effect.

[0027] 8. Adaptable to all temperature ranges and highly versatile. This invention controls the color of four powders through differentiated formulations. The colorant can also act as a melting point regulator, thereby creating material formulations suitable for different processing temperatures, which is beneficial for material performance selection in industrial applications. Attached Figure Description

[0028] Figure 1 Microstructure analysis of the compressed particles; Figure 2 Microstructure analysis of particles after high-temperature curing; Figure 3 Energy dispersive spectroscopy (EDS) analysis of needle-like and rod-shaped products inside the particles after high-temperature curing. Detailed Implementation

[0029] In the description of this invention, terminology is used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0030] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials, reagents or instruments used, unless otherwise specified by the manufacturer, are all commercially available reagents and materials; the conditions not specified in the examples are all carried out according to conventional conditions or conditions recommended by the manufacturer. At the same time, the present invention does not limit the source of the raw materials used. Unless otherwise specified, the raw materials used in the present invention are all commercially available products in this technical field.

[0031] Example 1 (Medium and Low Temperature Operating Conditions - Grayish-white Modifier) This embodiment provides a grayish-white waste incineration fly ash pretreatment modifier suitable for ambient temperature to 600℃. The formula is as follows by mass percentage: 92% cementing material (20% silica fume, 10% fly ash, 62% mineral powder), and 8% colorant + co-solvent (5% dolomite powder, 3% albite).

[0032] Application process: Take 100 parts of waste incineration fly ash, add 45 parts of the modifier of this embodiment, mix evenly, add 8% of the total mass of the powder with water, stir and mix evenly, press into 2 mm homogeneous particles, and cure at 60℃ for 6 hours to obtain grayish-white homogeneous reinforced particles.

[0033] Performance testing: The granules did not disintegrate after soaking in water at room temperature for 72 hours, and were not damaged after intermittent mechanical washing for 240 minutes; the granules did not change color after washing and desalting, and the washing brine was clear and free of colored impurities; the granules remained intact without cracking after calcination at 600℃ for 2 hours; the granules turned slightly white after high-temperature cooling, with no pollutant leaching, and the dioxin residue met the national environmental protection standards.

[0034] Example 2 (Medium and Low Temperature Operating Conditions - Black Modifier) This embodiment provides a pretreatment modifier for black waste incineration fly ash that is suitable for temperatures from room temperature to 600℃. The formula is as follows by mass percentage: 95% cementing material (55% blast furnace slag powder, 25% yellow phosphorus slag powder, 15% lithium slag powder), and 5% colorant + co-solvent (1% oxide powder, 4% lithium ore powder).

[0035] Application process: Take 100 parts of waste incineration fly ash, add 50 parts of the modifier in this embodiment, mix evenly, add 13% of the total mass of the powder with water, press into 4 mm homogeneous particles, and cure at 45℃ for 36 h to obtain black homogeneous reinforced particles.

[0036] Performance testing: The granules are high-strength and resistant to erosion, do not disintegrate after mechanical washing, and maintain structural integrity after prolonged immersion in water; the granules remain intact after high-temperature calcination at 600℃, and do not crack after rapid cooling in water at 500℃; no pollutants leak out during the washing process, the heavy metal solidification rate is ≥98%, and the washing salt water is clear and transparent.

[0037] Example 3 (High Temperature Condition - Red Modifier) This embodiment provides a pretreatment modifier for red waste incineration fly ash that is suitable for temperatures from room temperature to 1200℃. The formula is as follows by mass percentage: 91% cementing material (50% lithium slag powder, 25% mineral powder, 16% calcined kaolin), and 9% total percentage of colorant and co-solvent (3% iron hydroxide powder, 3% calcined red clay, 3% dolomite).

[0038] Application process: Take 100 parts of waste incineration fly ash, add 60 parts of the modifier in this embodiment, mix evenly, add 15% of the total mass of the powder with water, press into 3 mm homogeneous particles, and cure at 40℃ for 48 h to obtain red homogeneous reinforced particles.

[0039] Performance testing: After washing and desalination, the color remained unchanged; the particles withstood calcination at 1200℃ without damage; and the structure remained intact after direct immersion in water and rapid cooling at 800℃. After high-temperature cooling, the color turned slightly lighter red. There was no equipment ring formation or kiln blockage during the calcination process. Dioxins were completely sealed without leakage, and heavy metals did not leach out. The product exhibited excellent mechanical strength.

[0040] Example 4 (High Temperature Condition - Light Red Modifier) This embodiment provides a pink waste incineration fly ash pretreatment modifier suitable for ambient temperature to 1200℃. The formula is as follows by mass percentage: 93% cementing material (48% blast furnace slag powder, 30% lithium slag powder, 15% yellow phosphorus slag powder), and 7% total percentage of colorant and co-solvent (3% red granite powder, 1% cuprous oxide, 1% iron oxide powder, and 2% wood ash).

[0041] Application process: Take 100 parts of waste incineration fly ash, add 80 parts of the modifier of this embodiment, mix evenly, add 20% of the total mass of the powder with water, press into 3 mm homogeneous particles, and cure at 40℃ for 48 h to obtain light red homogeneous reinforced particles.

[0042] Performance testing: The granules have excellent resistance to high temperature, rapid cooling, and water washing, meeting the core requirements of "three no-rot"; after calcination at 1200℃, the granules have a dense structure and stable color after water quenching; no pollutants overflow during the water washing and desalination process, and the washing water is clean, completely solving the problems of scaling and pollutant residue in traditional process equipment.

[0043] like Figure 1 As shown, it illustrates the pressed granules, with relatively dense internal powder particles. The curing results show that the particle strength meets the core performance requirement of "three no-rot" (meaning the particles are not easily rotten).

[0044] like Figure 2 As shown, the non-dense structure formed inside the particles after high-temperature curing facilitates the rapid dissolution of soluble salts within the dechlorination stage. Results indicate that after multi-stage washing, the chloride content of the particles meets the requirements for building materials.

[0045] like Figure 3 As shown, it displays the energy spectrum of the non-dense structure, and the results show that calcium oxide, calcium sulfate, aluminate and silicate components in fly ash all participate in the reaction, thereby realizing the effective resource utilization of fly ash components.

[0046] It should be noted that the specific embodiments described above are exemplary, and those skilled in the art can devise various solutions inspired by the disclosure of this invention, all of which fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification is illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents.

Claims

1. A pretreatment modifier for waste incineration fly ash, characterized in that, By weight percentage, it contains no more than 10% functional additives and no less than 90% binding materials, wherein the binding materials are one or more of blast furnace slag powder, fly ash, yellow phosphorus slag powder, lithium slag powder, steel slag powder, silica fume, calcined clay, and calcined kaolin; and the functional additives are one or more of colorants and solubilizers.

2. The waste incineration fly ash pretreatment modifier according to claim 1, characterized in that, The fluxing agent is one or more of the following: dolomite, albite, red granite powder, laterite, iron oxide or hydroxide powder, iron ore powder, cuprous oxide, lithium ore powder, wood ash, lithium slag powder, and coal powder.

3. The waste incineration fly ash pretreatment modifier according to claim 1, characterized in that, The colorant is one or more of the following: red granite powder, calcined laterite, iron oxide or hydroxide powder, iron ore powder, potassium feldspar, cuprous oxide, and coal powder.

4. The use of the waste incineration fly ash pretreatment modifier according to any one of claims 1-3 in the harmless treatment of solid waste.

5. The use according to claim 4, characterized in that, The fly ash from waste incineration is dry ash from waste-to-energy plants that has not undergone chelation treatment.

6. The use according to claim 4, characterized in that, By weight fraction, 80 parts of waste incineration fly ash pretreatment modifier are added for every 100 parts of waste incineration fly ash.

7. A method for using a pretreatment modifier for waste incineration fly ash, characterized in that, Includes the following steps: By weight fraction, 100 parts of waste incineration fly ash, with the addition of 30-80 parts of the waste incineration fly ash pretreatment modifier as described in any one of claims 1-3, and 8-20% water by weight of the total powder, are used for fly ash treatment. Grayish-white and black powders are suitable for medium-low temperature fly ash treatment from room temperature to 600℃; Red, yellow, and green powders are suitable for fly ash treatment at temperatures ranging from room temperature to 1200℃.

8. The method of using the waste incineration fly ash pretreatment modifier according to claim 7, characterized in that, The fly ash treatment time is 6~48 hours.

9. The method of using the waste incineration fly ash pretreatment modifier according to claim 7, characterized in that, Before the fly ash is treated, the mixture is compressed into particles of 1-5 mm.

10. The method of using the waste incineration fly ash pretreatment modifier according to claim 9, characterized in that, The fly ash treated particles do not crack when calcined at high temperatures of 400~1200℃; the fly ash treated particles do not break when immersed in room temperature water at 800℃.

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