Sludge incineration ash treatment method based on mineralization reaction, mineralized product and application

Abstract

The invention discloses a sludge incineration ash treatment method based on mineralization reaction, a mineralization product and application, and belongs to the technical field of solid waste treatment and resource utilization. The method comprises the following steps: crushing and screening sludge incineration ash, carrying out acid leaching activation on the ash by using diluted hydrochloric acid, adjusting the pH value to 3-5, and filtering to obtain a pretreated ash solution; and carrying out mineralization reaction on the pretreated ash solution and CO2, and carrying out solid-liquid separation to obtain a carbonate mineralizer. The sludge incineration ash is used for replacing traditional natural minerals to serve as a CO2 mineralization reaction raw material, the purpose of treating waste with waste is achieved, calcium and magnesium ions in the ash are efficiently extracted through an acid leaching activation technology, heavy metal impurities are synchronously removed, and the problems of high raw material cost, large mining energy consumption and solid waste landfill pollution of a traditional mineralization technology are solved; the defects of an existing sludge incineration ash residue resource utilization method in the aspects of heavy metal solidification and harmlessness are overcome, the CO2 storage amount of a single ton of ash residues reaches 0.2-0.3 ton, and the cost is reduced by 40%-50%.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste treatment and resource utilization, and specifically relates to a sludge incineration ash treatment method based on a mineralization reaction, and a mineralized product and application thereof. Background Art

[0002] With the acceleration of urbanization and the booming industrial production, the scale of urban wastewater treatment continues to expand. The resulting sewage sludge incineration ash, as a solid waste, faces increasingly prominent challenges in its treatment and disposal. Sludge incineration ash is rich in heavy metals (such as lead, mercury, and cadmium) and organic pollutants (such as polycyclic aromatic hydrocarbons and dioxins). If these hazardous substances are directly landfilled without proper treatment, they not only consume valuable land resources but also enter the soil and groundwater systems through infiltration and leaching, posing a long-term threat to the ecological environment and human health. Therefore, achieving the harmlessness, reduction, and resource utilization of sewage sludge incineration ash has become a key issue in environmental science and engineering. Currently, the main treatment method for sewage sludge incineration ash is landfill, which poses problems of land resource utilization and the risk of heavy metal leaching. Furthermore, traditional carbon dioxide mineralization technologies rely on natural mineral raw materials such as olivine and serpentine, which have drawbacks such as high raw material costs and high energy consumption in mining.

[0003] CO2 capture and storage (CCS) has garnered widespread attention as a key means of reducing greenhouse gas emissions. Among these technologies, CO2 mineralization, which can permanently store CO2 in a stable carbonate form within geological structures or industrial products, demonstrates significant potential. This technology utilizes natural minerals rich in alkaline metals such as calcium and magnesium (such as olivine, serpentine, and dolomite) to react with CO2 gas to form stable carbonate minerals, thereby achieving CO2 sequestration. In recent years, researchers both domestically and internationally have conducted extensive research on the reaction mechanism, process optimization, and economic evaluation of CO2 mineralization, achieving significant progress. Despite its significant theoretical environmental benefits and potential economic value, CO2 mineralization technology faces numerous challenges in its large-scale commercial application. Conventional CO2 mineralization technology relies heavily on natural mineral raw materials, whose mining, processing, and transportation are energy-intensive and costly, severely hindering the technology's economic viability and widespread application. Landfill remains the primary method for disposing of solid wastes such as sludge incineration ash, exacerbating land resource constraints. The long-term dissolution risk of heavy metals and organic pollutants in the ash poses a potential threat to the surrounding ecological environment. The integration of CO2 mineralization technology and sludge incineration ash resource utilization is still in its early stages, lacking systematic process optimization and integrated innovation, making it difficult to achieve efficient conversion of sludge incineration ash and stable CO2 storage. The low added value of the mineralized products and the lack of effective application pathways have resulted in limited overall economic benefits for the technology, making it difficult to develop a sustainable business model.

[0004] To address the above problems, a new CO2 mineralization technology has been developed, using sludge incineration ash instead of natural minerals as the raw material for the mineralization reaction. This can not only effectively reduce the cost of raw materials, but also realize the resource utilization of sludge incineration ash, while solving the dual goals of solid waste landfill pollution and CO2 emission reduction. It has important research significance and application value. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a sludge incineration ash treatment method based on mineralization reaction, as well as mineralized products and applications, so as to solve the technical problems of low resource utilization rate of existing sludge incineration ash, incomplete harmless treatment of heavy metals, high raw material cost of CO2 mineralization technology and low added value of products.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a method for treating sludge incineration ash based on a mineralization reaction, comprising: After the sludge incineration ash is crushed and screened, the ash is acid-leached and activated with dilute hydrochloric acid, and the pH value is adjusted to 3-5. After filtration, a pretreated ash solution is obtained; the pretreated ash solution is subjected to a mineralization reaction with CO2, and after solid-liquid separation, carbonate mineralization is obtained.

[0007] Preferably, the particle size of the sludge incineration ash after crushing and screening is ≤100 μm.

[0008] Preferably, the mass concentration of dilute hydrochloric acid is 5%-10%.

[0009] Preferably, the pretreated ash solution is Ca-rich 2+ and Mg 2+ of solution.

[0010] Preferably, the pH value of the mineralization reaction is 7-9; the temperature of the mineralization reaction is 50-80° C.; and the pressure of the mineralization reaction is 0.1-0.5 MPa.

[0011] Preferably, the mineralization reaction time is 1-3 hours, and the mineralization rate is ≥85%.

[0012] The present invention also discloses a carbonate mineralized product, which is prepared by adopting the above-mentioned sludge incineration ash treatment method based on mineralization reaction. The carbonate mineralized product is a calcium carbonate / magnesium carbonate precipitate.

[0013] The present invention also discloses the use of carbonate mineralized products obtained by the above-mentioned sludge incineration ash treatment method based on mineralization reaction in engineering materials, and the carbonate mineralized products are directly used as engineering materials after being dried.

[0014] The present invention also discloses the use of carbonate mineralized material obtained by the above-mentioned sludge incineration ash treatment method based on mineralization reaction in underground filling, wherein the carbonate mineralized material is mixed with a cementitious material in a mass ratio of 1:(1-3) to prepare an underground filling body with a compressive strength ≥15MPa.

[0015] The present invention also discloses the application of carbonate mineralized products obtained by the above-mentioned sludge incineration ash treatment method based on mineralization reaction in the production of building materials, and adopts carbonate mineralized products to replace 20%-30% of natural sand and gravel building material raw materials.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method for treating sludge incineration ash based on mineralization reaction, in which sludge incineration ash is used to replace traditional natural minerals as raw materials for CO2 mineralization reaction, thus achieving waste treatment with waste, avoiding the occupation of land resources by ash landfill and the risk of heavy metal dissolution pollution. Calcium and magnesium ions in the ash are efficiently extracted through an acid leaching activation process, and heavy metal impurities such as arsenic and lead are removed simultaneously, ensuring a low concentration of heavy metal leaching in the product, thus blocking the secondary pollution chain at the source. This method solves the problems of high raw material cost, high mining energy consumption and solid waste landfill pollution in traditional mineralization technology, and solves the shortcomings of existing sludge incineration ash resource utilization methods in terms of heavy metal solidification and harmlessness. The CO2 storage capacity per ton of ash reaches 0.2-0.3 tons, and the mineralization efficiency is ≥85%, breaking through the traditional static reaction rate limit, increasing the reaction rate by 20%-30%, and significantly reducing the atmospheric CO2 concentration. It replaces traditional high-carbon building materials such as cement and lime, indirectly reducing carbon emissions in the building materials production process, and reducing raw material costs by 40%-50%. Mineralized products, as high-value-added engineering materials, enhance product value, form a "waste-to-waste" circular economy model, promote green transformation in the building materials industry, and reduce ecological damage from natural sand and gravel mining. They can be connected to municipal sludge treatment plants, solving the ash disposal problem and reducing its disposal costs. They provide low-carbon raw materials for the building materials and mining industries, promoting the green upgrade of traditional industries. Mineralized products are converted into fill in mining areas, achieving both ecological restoration and carbon sequestration in goafs. This not only achieves high-value utilization of sludge incineration ash and permanent storage of CO2, but also provides a solution for solid waste treatment and carbon emission reduction through the synergy of technical, economic, environmental, and social benefits.

[0017] The present invention also discloses a carbonate mineralization product obtained by a sludge incineration ash treatment method based on a mineralization reaction. The main component is calcium carbonate / magnesium carbonate, and the chemical composition is stable and controllable, which avoids the problem of fluctuations in the composition of natural mineral raw materials, provides high-quality raw materials for engineering applications, and can be used directly as engineering materials without secondary purification. The mineralized product has high crystallinity and regular morphology. When used as an engineering material, the underground filling body prepared in combination with cementitious materials has high compressive strength, which meets the strict requirements of mining on the strength of the filling body. In the production of building materials, it can be used as a concrete aggregate or sintered brick additive to replace natural sand and gravel, significantly improving the mechanical properties and durability of building materials. The carbonate mineralization product has excellent thermal stability and is suitable for engineering applications in high temperature environments. The product has a dense surface, low porosity, high chemical stability, and resistance to acid and alkali corrosion, which extends the service life of the material and reduces maintenance costs.

[0018] The present invention also discloses the application of carbonate mineralization products of the sludge incineration ash treatment method based on mineralization reaction in engineering materials. Through the coordinated regulation of pH-temperature-pressure and optimization of dynamic reaction time, the carbonate mineral content is ≥90%, which can be directly used as an engineering material without the need for secondary purification, simplifying the process flow and reducing costs. The CO2 storage capacity of a single ton of sludge ash reaches 0.2-0.3 tons, and the mineralization efficiency is ≥85%, breaking through the traditional static reaction rate limit, and the reaction rate is increased by 20%-30%, achieving the dual goals of solid waste treatment and carbon emission reduction. Replacing natural minerals such as olivine and serpentine with sludge incineration ash can reduce the cost of raw materials by 40%-50%, while solving the problem of solid waste landfill pollution, with significant economic and environmental benefits.

[0019] The present invention also discloses the application of carbonate mineralization products of the sludge incineration ash treatment method based on mineralization reaction in underground filling. The mineralization product is mixed with a cementitious material (such as cement, slag powder) in a mass ratio of 1: (1-3), and an underground filling body with a compressive strength of ≥15MPa is successfully prepared, which meets the mining filling needs of the mine, effectively supports the goaf, and reduces the risk of geological disasters. The use of mineralization products to prepare the filling body reduces the use of traditional filling materials, reduces the cost of goaf management, and improves resource utilization efficiency. The acid leaching activation process synergistically removes heavy metal impurities such as arsenic and lead, ensuring that the heavy metal leaching concentration in the filling body is lower than the standard, thereby protecting the safety of underground operations and the ecological environment.

[0020] The present invention also discloses the application of carbonate mineralization products from a sludge incineration ash treatment method based on a mineralization reaction in building materials production. As concrete aggregate or sintered brick additives, the mineralized products can replace 20%-30% of natural sand and gravel, reducing the pressure on natural resource exploitation in the building materials industry and lowering carbon emissions. Converting sludge incineration ash into building material raw materials realizes the resource utilization of waste and promotes the development of a circular economy. Acid leaching and solidification treatment ensures that the heavy metal leaching concentration in building materials products meets standards, avoiding the risk of secondary pollution and improving the environmental safety of building materials products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the sludge incineration ash treatment method based on mineralization reaction disclosed in the present invention. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] In the present invention, unless otherwise specified, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0024] In the present invention, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0025] In the present invention, unless otherwise specified, percentages (%) or parts refer to percentages by weight or parts by weight relative to the composition.

[0026] In the present invention, unless otherwise specified, the components involved or their preferred components can be combined with each other to form a new technical solution.

[0027] In this disclosure, unless otherwise specified, the numerical range "ab" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "6-22" indicates that all real numbers between "6-22" are listed herein, and "6-22" is merely an abbreviation for these numerical combinations.

[0028] The "range" disclosed in the present invention is in the form of lower limit and upper limit, which can be one or more lower limits, and one or more upper limits respectively.

[0029] In the present invention, the term "and / or" used herein refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0030] In the present invention, unless otherwise specified, each reaction or operation step can be carried out sequentially or in accordance with the order. Preferably, the reaction method herein is carried out sequentially.

[0031] Unless otherwise indicated, the professional and scientific terms used herein are the same as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied to the present invention.

[0032] The present invention provides a method for treating sludge incineration ash based on a mineralization reaction, comprising: Step 1, ash pretreatment; Step 101: crushing and screening the sludge incineration ash to control the particle size to ≤100 μm to improve the reaction activity; Step 102: Use 5%-10% dilute hydrochloric acid to acid-activate the ash, adjust the pH value of the system to 3-5, dissolve the calcium and magnesium metal ions therein, and remove heavy metal impurities such as arsenic and lead by filtration to obtain Ca-enriched 2+ Mg 2+solution; by pre-treating the ash, its reactivity is improved, and calcium and magnesium ions are dissolved through acid leaching activation, while heavy metal impurities are removed.

[0033] Step 2, CO2 mineralization reaction; Step 201: contacting and reacting the pretreated ash solution with CO2 gas in a closed reaction system; Step 202: Improve mineralization efficiency by dynamically controlling the following conditions: pH control: An automatic dosing system is used to maintain the pH value of the reaction system in the range of 7-9, with a pH value of 8-8.5 being preferred to balance the reaction rate and product stability; Temperature control: The reaction temperature is maintained at 50-80°C through a jacket heat exchanger to accelerate ion migration and carbonate crystallization; Pressure control: Introduce CO2 gas and control the system pressure to 0.1-0.5MPa to enhance the CO2 dissolution and mass transfer efficiency; The residence time is dynamically adjusted to 1-3 hours according to the solution ion concentration to ensure that the mineralization rate is ≥85%. After the reaction, the solid-liquid separation is performed to obtain carbonate mineralization, namely calcium carbonate / magnesium carbonate precipitate.

[0034] The product is a mixture of magnesium carbonate and calcium carbonate. The longer the reaction time, the more impurities it contains. The order of cation precipitation in the solution is magnesium ions, calcium ions and other cations.

[0035] To address the bottleneck of gas-liquid-solid multiphase mass transfer in traditional CO2 mineralization reactions, this invention establishes a pH-temperature-pressure coordinated optimization system. By establishing a process system with dynamic pH-temperature-pressure coordinated optimization, reaction conditions and residence time are adjusted in real time, overcoming the bottleneck of gas-liquid-solid multiphase mass transfer. During the CO2 mineralization reaction, an automatic dosing system maintains the reaction system pH within the range of 7-9 (preferably 8-8.5 to balance reaction rate and product stability). A jacketed heat exchanger precisely controls the reaction temperature between 50-80°C, accelerating ion migration and carbonate crystallization. Simultaneously, CO2 gas is introduced and the system pressure is controlled at 0.1-0.5 MPa to enhance CO2 dissolution and mass transfer efficiency. Furthermore, the reaction residence time is dynamically adjusted by 1-3 hours based on the solution ion concentration to ensure a mineralization rate of ≥85%. Compared to traditional static reactions, this dynamic control process increases the reaction rate by 20%-30% and achieves a carbonate mineralization content of ≥90%, significantly improving mineralization efficiency and product quality.

[0036] Traditional CO2 mineralization technology relies on natural mineral raw materials such as olivine and serpentine, which has problems such as high cost and high energy consumption in mining. At the same time, sludge incineration ash is mostly disposed of by landfill, which occupies a large amount of land resources and has the risk of heavy metal dissolution. This invention proposes for the first time to use sludge incineration ash to replace natural minerals as raw materials for CO2 mineralization reaction. The particle size is controlled by crushing and screening (≤100μm) to improve the reaction activity. Then, 5%-10% concentration of dilute hydrochloric acid is used for acid leaching activation. The pH value of the system is adjusted to 3-5, which successfully dissolves the calcium and magnesium metal ions in the ash. At the same time, the filtration process is used to effectively remove heavy metal impurities such as arsenic and lead, and obtain Ca-enriched ash. 2+ Mg 2+ This innovation not only solves the dual challenges of high raw material costs and solid waste landfill pollution in traditional mineralization technology, but also enables a single ton of ash to store 0.2-0.3 tons of CO2, reducing raw material costs by 40%-50%, achieving waste resource utilization and effective cost control.

[0037] The present invention also discloses carbonate minerals obtained by the above-mentioned sludge incineration ash treatment method based on mineralization reaction, and the calcium carbonate / magnesium carbonate precipitate is directly used as an engineering material after drying. By expanding the resource application scenarios of the mineralized products, the mineralized products are directionally converted into high-value-added engineering materials, such as underground fillings with a compressive strength of ≥15MPa or building materials that replace 20%-30% of natural sand and gravel, forming a "solid waste treatment-carbon sequestration-material regeneration" closed-loop chain. At the same time, through acid leaching and solidification, the heavy metal leaching concentration is reduced to below the standard value, achieving a deep coupling of environmental and economic benefits.

[0038] The carbonate mineralization product is mixed with a cementitious material (such as cement, slag powder) in a mass ratio of 1: (1-3) to prepare an underground filling body with a compressive strength ≥ 15 MPa.

[0039] This invention expands the application of mineralized products into a deep resource, transforming them into high-value-added engineering materials. In the field of underground filling, the mineralized products are mixed with cementitious materials (such as cement and slag powder) in a mass ratio of 1:(1-3), successfully producing a filling material with a compressive strength of ≥15 MPa, providing an effective filling solution for mining.

[0040] The mineralized products can be used as concrete aggregates or sintered brick additives to replace 20%-30% of natural sand and gravel, reducing carbon emissions from building materials production.

[0041] In building materials production, the mineralized products can be used as concrete aggregates or sintered brick additives, replacing 20%-30% of natural sand and gravel. This reduces carbon emissions from building materials production while enabling resource recycling. Furthermore, through acid leaching and solidification, heavy metal leaching concentrations are reduced to below national standards, ensuring environmental safety during application. This creates a complete closed-loop chain of "solid waste treatment-carbon sequestration-material regeneration," achieving a deep coupling of environmental and economic benefits and providing a new technical path and development model for sludge incineration ash treatment and CO2 emission reduction.

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention shown here can generally be arranged and designed through various different configurations. Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] Example 1 A method for treating sludge incineration ash based on a mineralization reaction, comprising: 1000g of sewage sludge incineration ash (CaO content 32%) was crushed to an average particle size of 80μm, mixed with 8% dilute hydrochloric acid, and the pH adjusted to 4.2. Filtering removed impurities to obtain a calcium-rich solution with a calcium ion dissolution rate of 92%. CO2 gas was introduced into the solution, and the reaction pressure was controlled at 0.3MPa, temperature at 65°C, and pH 8.3 for 2.5 hours. After solid-liquid separation, the resulting calcium carbonate product showed a CO2 sequestration capacity of 0.23kg, a mineralization rate of 91%, and a compressive strength of 20MPa. This product was mixed with cement in a ratio of 1:2 to prepare a backfill material. After 28 days, the compressive strength reached 18MPa, meeting mine backfill requirements.

[0044] Example 2 A method for treating sludge incineration ash based on a mineralization reaction, comprising: By comparing different acid leaching conditions in Example 1, it was found that when 10% hydrochloric acid (pH 3.5) was used to activate the ash, the calcium ion dissolution rate was increased by 10% compared with the 8% dilute hydrochloric acid system, and the mineralization reaction rate was increased by 7%, confirming the process advantage of hydrochloric acid activation.

[0045] Example 3 A method for treating sludge incineration ash based on a mineralization reaction, comprising: Take 1000g of sludge incineration ash, crush and screen it, and control the average particle size to 100μm to improve the reaction activity. Use 8% dilute hydrochloric acid to acid-activate the ash, adjust the pH value of the system to 4.0, dissolve the calcium and magnesium metal ions therein, and remove heavy metal impurities such as arsenic and lead by filtration to obtain Ca-enriched 2+ Mg 2+ The pretreated ash solution is contacted with CO2 gas in a closed reaction system for reaction. An automatic dosing system is used to maintain the pH value of the reaction system within the range of 8.2 to balance the reaction rate and product stability. The reaction temperature is maintained at 65°C by a jacketed heat exchanger to accelerate ion migration and carbonate crystallization. CO2 gas is introduced and the system pressure is controlled at 0.3 MPa to enhance the CO2 dissolution and mass transfer efficiency. The residence time is dynamically adjusted to 2 hours according to the solution ion concentration to ensure a mineralization rate of 90%.

[0046] After the reaction is complete, solid-liquid separation is performed to obtain a calcium carbonate / magnesium carbonate precipitate, which is dried and used directly as an engineering material. This mineralized product is mixed with cement in a mass ratio of 1:3 to prepare an underground filling material with a compressive strength of 18 MPa.

[0047] Example 4 A method for treating sludge incineration ash based on a mineralization reaction, comprising: 1200g of sludge incineration ash was crushed and sieved to control the average particle size to 80μm to improve the reaction activity. The ash was acid-leached and activated with 10% dilute hydrochloric acid, and the pH value of the system was adjusted to 3.5 to dissolve the calcium and magnesium ions therein. At the same time, heavy metal impurities such as arsenic and lead were removed by filtration to obtain Ca-enriched 2+ Mg 2+ The pretreated ash solution is contacted with CO2 gas in a closed reaction system for reaction. An automatic dosing system is used to maintain the pH value of the reaction system within the range of 8.5 to balance the reaction rate and product stability. The reaction temperature is maintained at 70°C by a jacketed heat exchanger to accelerate ion migration and carbonate crystallization. CO2 gas is introduced and the system pressure is controlled at 0.4 MPa to enhance the CO2 dissolution and mass transfer efficiency. The residence time is dynamically adjusted to 2.5 hours according to the solution ion concentration to ensure a mineralization rate of 95%.

[0048] After the reaction is complete, solid-liquid separation is performed to obtain a calcium carbonate / magnesium carbonate precipitate, which is then dried and used directly as an engineering material. This mineralized product can be used as concrete aggregate, replacing 25% of natural sand and gravel, reducing carbon emissions from building material production.

[0049] Example 5 A method for treating sludge incineration ash based on a mineralization reaction, comprising: 1500g of sludge incineration ash was crushed and sieved to control the average particle size to 90μm to improve the reaction activity. The ash was acid-leached and activated with 6% dilute hydrochloric acid, and the pH value of the system was adjusted to 4.5 to dissolve the calcium and magnesium ions therein. At the same time, heavy metal impurities such as arsenic and lead were removed by filtration to obtain Ca-enriched 2+ Mg 2+ The pretreated ash solution is contacted with CO2 gas in a closed reaction system for reaction. An automatic dosing system is used to maintain the pH value of the reaction system within the range of 7.8 to balance the reaction rate and product stability. The reaction temperature is maintained at 60°C by a jacketed heat exchanger to accelerate ion migration and carbonate crystallization. CO2 gas is introduced and the system pressure is controlled at 0.2MPa to enhance the CO2 dissolution and mass transfer efficiency. The residence time is dynamically adjusted to 3h according to the solution ion concentration to ensure a mineralization rate of 85%.

[0050] After the reaction is complete, solid-liquid separation is performed to obtain a calcium carbonate / magnesium carbonate precipitate, which is dried and used directly as an engineering material. This mineralized product is mixed with slag powder in a mass ratio of 1:1 to prepare an underground filling material with a compressive strength of 15 MPa.

[0051] Example 6 A method for treating sludge incineration ash based on a mineralization reaction, comprising: Take 1000g of sludge incineration ash, crush and screen it, and control the average particle size to 100μm to improve the reaction activity. Use 5% dilute hydrochloric acid to acid-activate the ash, adjust the pH of the system to 3.0, dissolve the calcium and magnesium metal ions therein, and remove heavy metal impurities such as arsenic and lead by filtration to obtain Ca-enriched 2+ Mg 2+ The pretreated ash solution is contacted with carbon dioxide gas in a closed reaction system for reaction. An automatic dosing system is used to maintain the pH of the reaction system within the range of 7 to balance the reaction rate and product stability. The reaction temperature is maintained at 50°C using a jacketed heat exchanger to accelerate ion migration and carbonate crystallization. Carbon dioxide gas is introduced and the system pressure is controlled at 0.1 MPa to enhance the carbon dioxide dissolution and mass transfer efficiency. The residence time is dynamically adjusted to 1 hour based on the solution ion concentration to ensure a mineralization rate of ≥88%.

[0052] After the reaction is complete, solid-liquid separation is performed to obtain a calcium carbonate / magnesium carbonate precipitate, which is then dried and used directly as an engineering material. This mineralized product can be used as concrete aggregate, replacing 22% of natural sand and gravel, reducing carbon emissions from building material production.

[0053] Example 7 A method for treating sludge incineration ash based on a mineralization reaction, comprising: Take 1200g of sludge incineration ash, crush and screen it, and control the average particle size to 80μm to improve the reaction activity. Use 7% dilute hydrochloric acid to acid-activate the ash, adjust the pH of the system to 5, dissolve the calcium and magnesium metal ions therein, and remove heavy metal impurities such as arsenic and lead by filtration to obtain Ca-enriched 2+ Mg 2+ The pretreated ash solution is contacted with carbon dioxide gas in a closed reaction system for reaction. An automatic dosing system is used to maintain the pH of the reaction system within the range of 9 to balance the reaction rate and product stability. The reaction temperature is maintained at 80°C using a jacketed heat exchanger to accelerate ion migration and carbonate crystallization. Carbon dioxide gas is introduced and the system pressure is controlled at 0.5 MPa to enhance the carbon dioxide dissolution and mass transfer efficiency. The residence time is dynamically adjusted to 1.5 hours based on the solution ion concentration to ensure a mineralization rate of ≥92%.

[0054] After the reaction is complete, solid-liquid separation is performed to obtain a calcium carbonate / magnesium carbonate precipitate, which is then dried. The dried calcium carbonate / magnesium carbonate mineralization product is used as concrete aggregate, replacing 30% of natural sand and gravel, reducing carbon emissions from building material production.

[0055] Figure 1 This is a schematic diagram of the sludge incineration ash treatment method based on mineralization reaction disclosed in the present invention; as can be seen from the figure, the present invention discloses a sludge incineration ash treatment method based on mineralization reaction, including: crushing the sludge incineration ash, screening out ash with a particle size of ≤100μm, using a dilute hydrochloric acid solution to acid-activate the ash, adjusting the pH value to 3-5, and filtering to obtain a pretreated ash solution; after the pretreated ash solution is subjected to a mineralization reaction with CO2, after solid-liquid separation, carbonate mineralization is obtained, which can be used for engineering materials, underground filling and building materials production.

[0056] In summary, the present invention provides a mineralization-based sewage sludge incineration ash treatment method, mineralized products, and applications. This method first pre-treats the sewage sludge incineration ash by crushing and acid leaching to dissolve calcium and magnesium ions from the ash and remove heavy metal impurities. Then, a carbon dioxide mineralization reaction is carried out under dynamically controlled conditions (pH 7-9, temperature 50-80°C, pressure 0.1-0.5 MPa, and reaction time 1-3 hours) to produce calcium carbonate / magnesium carbonate mineralized products. Finally, the mineralized products are directly applied to engineering materials, such as underground filling materials with a compressive strength ≥15 MPa or building materials that replace 20%-30% of natural sand and gravel. This method innovatively utilizes sewage sludge incineration ash as a raw material in place of natural minerals for the mineralization reaction. The acid leaching activation process efficiently extracts calcium and magnesium ions, addressing the dual challenges of high raw material costs and solid waste landfill pollution associated with traditional mineralization technologies. Sludge incineration ash is used to replace traditional natural minerals (such as olivine and serpentine) as the raw material for CO2 mineralization. The acid leaching activation process is used to efficiently extract calcium and magnesium ions and remove heavy metal impurities, realizing raw material innovation and solid waste pollution resolution. The CO2 storage capacity per ton of ash reaches 0.2-0.3 tons and the cost is reduced by 40%-50%; a pH-temperature-pressure synergistic optimization system is established to dynamically control the reaction conditions and residence time, breaking through the bottleneck of gas-liquid-solid multiphase mass transfer, and the mineralization efficiency is increased to more than 85%, the reaction rate is increased by 20%-30%, and the carbonate mineralization content is ≥90%; the mineralization products are converted into high-value-added engineering materials, forming a closed-loop chain of "solid waste treatment-carbon storage-material regeneration", while achieving the standard heavy metal leaching concentration, and achieving a deep coupling of environmental and economic benefits.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating sludge incineration ash based on mineralization reaction, characterized in that: include: After the sludge incineration ash is crushed and screened, the ash is acid-leached and activated with dilute hydrochloric acid, the pH value is adjusted to 3-5, and the pretreated ash solution is obtained after filtering; The pretreated ash solution is subjected to a mineralization reaction with CO2 and then solid-liquid separation is performed to obtain carbonate mineralization.

2. The method for treating sludge incineration ash based on mineralization reaction according to claim 1, characterized in that: The particle size of the sludge incineration ash after crushing and screening is ≤100 μm.

3. The method for treating sludge incineration ash based on mineralization reaction according to claim 1, characterized in that: The mass concentration of the dilute hydrochloric acid is 5%-10%.

4. The method for treating sludge incineration ash based on mineralization reaction according to claim 1, characterized in that: The pretreated ash solution is Ca-enriched 2+ and Mg 2+ of solution.

5. The method for treating sludge incineration ash based on mineralization reaction according to claim 1, characterized in that: The pH value of the mineralization reaction is 7-9; the temperature of the mineralization reaction is 50-80° C.; and the pressure of the mineralization reaction is 0.1-0.5 MPa.

6. The method for treating sludge incineration ash based on mineralization reaction according to claim 1, characterized in that: The mineralization reaction time is 1-3 hours, and the mineralization rate is ≥85%.

7. A carbonate mineralization, characterized in that: It is prepared by the sludge incineration ash treatment method based on mineralization reaction according to any one of claims 1 to 8, wherein the carbonate mineralized product is a calcium carbonate / magnesium carbonate precipitate.

8. Use of the carbonate mineralized product obtained by the sludge incineration ash treatment method based on mineralization reaction according to any one of claims 1 to 7 in engineering materials, characterized in that: The carbonate mineralization is directly used as an engineering material after drying.

9. The use of carbonate mineralized products obtained by the sludge incineration ash treatment method based on mineralization reaction according to any one of claims 1 to 7 in underground filling, characterized in that: The carbonate mineralization and the cementitious material are mixed in a mass ratio of 1:(1-3) to prepare an underground filling body with a compressive strength ≥15MPa.

10. Use of the carbonate mineralized product obtained by the sludge incineration ash treatment method based on mineralization reaction according to any one of claims 1 to 7 in the production of building materials, characterized in that: Carbonate minerals are used to replace 20%-30% of natural sand and gravel as building materials.

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