Microbial-based multi-source solid waste aggregate for carbon sequestration in industrial flue gas and its preparation method

Abstract

This invention belongs to the field of solid waste resource utilization and dual-carbon technology, and relates to microbial-based multi-source solid waste aggregate for industrial flue gas carbon sequestration and its preparation method. Sulfuric acid slag and / or phosphorus mud are dried and ball-milled to obtain powder. The powder, alkali activator, and microbial powder are mixed evenly, and then water is added for granulation to obtain modified aggregate preforms. The modified aggregate preforms are then cultured and cured at a temperature of 20–60°C. The cultured and cured modified aggregate preforms are placed in industrial flue gas containing CO2 and mineralized and cured at a temperature of 80–200°C to obtain aggregate. The microbial powder is *Vibrio ammoniagenicus*. The aggregate prepared by this invention has excellent compressive strength and can simultaneously achieve solid waste resource utilization and efficient CO2 absorption during the preparation process, offering advantages such as high carbon sequestration efficiency and short production cycle.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization and dual carbon technology, and relates to microbial-multi-source solid waste-based aggregates for industrial flue gas carbon sequestration and their preparation methods. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Industrial solid waste containing heavy metals (lead, zinc, copper, chromium, etc.) can cause significant pollution to the ecological environment if it enters water and soil. Both sulfuric acid slag and phosphorus sludge are industrial solid wastes. Current methods for treating sulfuric acid slag include high-temperature chlorination to recover non-ferrous metals and iron resources, and hydration to recover precious metals. Phosphorus sludge is treated using physical methods to recover phosphorus. These methods are insufficient for completely treating sulfuric acid slag and phosphorus sludge. Aggregates, as essential building materials, are generally made from natural sand, crushed stone, or pebbles. However, natural sand, crushed stone, and pebbles are non-renewable natural resources; therefore, artificial aggregates are needed as alternatives. Currently, there are no records regarding the preparation of aggregates from sulfuric acid slag and phosphorus sludge. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide microbial-multi-source solid waste-based aggregates for industrial flue gas carbon sequestration and their preparation method. The aggregates prepared by the present invention have excellent compressive strength and can simultaneously achieve solid waste resource utilization and efficient CO2 absorption during the preparation process, with advantages such as high carbon sequestration efficiency and short production cycle.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] On one hand, a method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas involves drying and ball milling multi-source solid waste to obtain powder, mixing the powder, alkali activator, and microbial powder evenly, then adding water for granulation to obtain modified aggregate preforms, culturing and curing the modified aggregate preforms at a temperature of 20–60°C, and placing the cultured and cured modified aggregate preforms in industrial flue gas containing CO2 for mineralization curing at a temperature of 80–200°C to obtain aggregate.

[0007] The multi-source solid waste is sulfuric acid residue and / or phosphorus mud; the microbial powder is Thermovibrio ammonificans.

[0008] Artificial aggregates are generally prepared using a firing and vitrification method. However, research has found that the strength of aggregates made from sulfuric acid slag and / or phosphorus mud using conventional firing methods needs improvement. Furthermore, directly adding alkali activators to sulfuric acid slag and / or phosphorus mud results in low strength after gelation, which is detrimental to aggregate preparation. Therefore, this invention utilizes the alkaline earth metal oxides in sulfuric acid slag and / or phosphorus mud, which can chemically react with CO2 to form highly stable inorganic carbonates. This results in aggregates with higher strength, achieving high-value building materials while simultaneously absorbing CO2 and reducing greenhouse gas emissions. However, the natural carbonation process of minerals is extremely slow, with low carbon sequestration efficiency and a long production cycle, which is unfavorable for industrial production. This invention adds an alkaline activator and Thermovibrio ammonificans. After cultivation and mineralization, Thermovibrio ammonificans secretes carbonic anhydrase in the material system of this invention to catalyze the reaction of CO2 with alkaline components such as silicates and alkaline earth metal oxides in the aggregate embryo to generate calcium carbonate with higher strength. This calcium carbonate fills the pores in the aggregate embryo, giving the prepared multi-source solid waste-based carbon-fixing aggregate higher compressive strength.

[0009] On the other hand, a microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas is obtained by the above preparation method.

[0010] The beneficial effects of this invention are as follows:

[0011] (1) The raw materials of the microbial-multi-source solid waste-based carbon fixation aggregate prepared by this invention are all from solid waste. Alkali-activated solid waste can be used to replace traditional quicklime, sodium hydroxide and other alkali activators, which can greatly dispose of solid waste, realize the high-value resource utilization of solid waste and greatly save natural resources.

[0012] (2) The method of the present invention uses industrial flue gas containing CO2 gas for mineral curing. Compared with traditional natural curing, the surface of carbonized aggregate is more dense and the compressive strength is also improved.

[0013] (3) By introducing microorganisms that can secrete carbonic anhydrase, this invention can significantly accelerate the carbonation process and increase the amount of CO2 fixed, thereby improving the performance of aggregates and having significant carbon emission reduction significance. Detailed Implementation

[0014] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0015] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0016] Given that existing methods for preparing artificial aggregates are not conducive to the preparation of aggregates from sulfuric acid slag and phosphorus mud, this invention proposes a microbial-multi-source solid waste-based aggregate and its preparation method for carbon sequestration in industrial flue gas.

[0017] A typical embodiment of the present invention provides a method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas. The method involves drying and ball milling the multi-source solid waste to obtain powder; mixing the powder, an alkali activator, and microbial powder evenly; adding water and granulating to obtain modified aggregate preforms; culturing and curing the modified aggregate preforms at a temperature of 20–60°C; and placing the cultured and cured modified aggregate preforms in industrial flue gas containing CO2 and mineralizing them at a temperature of 80–200°C to obtain the aggregate.

[0018] The multi-source solid waste is sulfuric acid residue and / or phosphorus mud; the microbial powder is Thermovibrio ammonificans.

[0019] Experiments show that the aggregate prepared by the above method has higher strength, with a compressive strength of up to 9.6 MPa.

[0020] In some embodiments, the drying temperature for multi-source solid waste is 110–120°C, and the drying time is 10–14 hours.

[0021] In some embodiments, the parameters for ball milling the dried multi-source solid waste are: ball mill speed set to 180-220 r / min, tumbling speed set to 4-6 times / min, and ball milling time set to 20-40 min.

[0022] In some embodiments, the alkali activator is one or more of carbide slag, steel slag, and fly ash.

[0023] In some embodiments, the mass ratio of powder, alkali activator and microbial powder is 55-80:15-35:5-10.

[0024] In some embodiments, the powder is mixed with an alkali activator to obtain a mixture, and the mixture is then mixed evenly with microbial powder and granulated with water.

[0025] In one or more embodiments, during the granulation process, the mass ratio of the mixture to water is 1:0.05 to 0.8, preferably 1:0.50 to 0.8. In this invention, the above-mentioned mixture is thoroughly mixed with water, resulting in good strength and the formation of uniform CO2 channels. During the curing process, microorganisms multiply and secrete carbonic anhydrase, which can better react with CO2 in the subsequent mineralization process.

[0026] In some embodiments, the cultivation and maintenance time is 6 to 18 hours.

[0027] In some embodiments, the CO2-containing industrial flue gas is one or more of cement kiln tail gas, coal gasification tail gas, and chemical tail gas.

[0028] In some embodiments, the volume concentration of carbon dioxide in the mineralization process is 20-25%.

[0029] In some embodiments, the mineralization curing time is 4 to 10 hours.

[0030] Another embodiment of the present invention provides a microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas, obtained by the above preparation method.

[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0032] In the following examples, the microbial powder was *Thermovibrio ammonificans*, purchased from Ningbo Taisto Biotechnology Co., Ltd.

[0033] The compressive strength of the cylinder was tested in accordance with the standard "Lightweight aggregates and their test methods - Part 1: Lightweight aggregates" (GB / T 17431.1-2010).

[0034] Carbon dioxide curing amount: Thermogravimetric analysis was used, and the DTA / TG curve was used to calculate the amount using the following formula:

[0035]

[0036] In the formula: E is the carbon fixation rate, %; m 550℃ The mass of the sample at 550℃; m 1000℃ m0 represents the sample mass at 1000℃; m0 represents the original sample mass.

[0037] Example 1

[0038] A method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas, comprising the following specific steps:

[0039] (1) Preparation of phosphorus mud powder: The phosphorus mud was dried at 115℃ for 12 hours, and then ball-milled (ball mill speed set to 200r / min, turning speed set to 5 times / min) for 30 minutes to obtain 80-100 mesh phosphorus mud powder.

[0040] (2) Weigh 70 kg of phosphorus mud powder, 25 kg of carbide slag and 5 kg of microbial powder, mix them evenly, and granulate them with 70 kg of water to obtain modified aggregate blanks containing microbial components.

[0041] (3) The modified aggregate preform containing microbial components was cultured at 40°C for 12 hours.

[0042] (4) After the modified aggregate blanks are grown, they are placed in a mineralization curing box, and coal gasification tail gas is introduced. The temperature is 120℃ and the CO2 concentration is 20%. After mineralization curing for 7 hours, carbon-fixed aggregate is obtained.

[0043] The compressive strength of the carbon-fixed aggregate prepared in this embodiment is 7.6 MPa, and the CO2 solidification amount is 6.7 kg.

[0044] Example 2

[0045] A method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas, comprising the following specific steps:

[0046] (1) Preparation of sulfuric acid residue powder: The sulfuric acid residue was dried at 115℃ for 12h, and then ball-milled (ball mill speed set at 200r / min, turning speed set at 5 times / min) for 40min to obtain sulfuric acid residue powder of 80-100 mesh.

[0047] (2) Weigh 55 kg of sulfuric acid slag powder, 20 kg of steel slag, 15 kg of fly ash and 10 kg of microbial powder, mix them evenly, and granulate them with 50 kg of water to obtain modified aggregate blanks containing microbial components.

[0048] (3) The modified aggregate preform containing microbial components was cultured at 50°C for 10 h.

[0049] (4) After the modified aggregate blanks are grown, they are placed in a mineralization curing box, and cement kiln exhaust gas is introduced. The temperature is 150℃ and the CO2 volume concentration is 22%. The mineralization curing is carried out for 10 hours.

[0050] The compressive strength of the carbon-fixed aggregate prepared in this embodiment is 8.1 MPa, and the CO2 solidification amount is 7.3 kg.

[0051] Example 3

[0052] A method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas, comprising the following specific steps:

[0053] (1) Preparation of solid waste powder: sulfuric acid residue and phosphorus mud were dried at 115℃ for 12h, and then ball milled (ball mill speed set at 200r / min, turning speed set at 5 times / min) for 30min to obtain sulfuric acid residue powder and phosphorus mud powder of 80-100 mesh.

[0054] (2) Weigh 30 kg of sulfuric acid slag powder, 25 kg of phosphorus mud powder, 12 kg of carbide slag, 25 kg of steel slag, and 8 kg of microbial powder, mix them evenly, and granulate them with 60 kg of water to obtain modified aggregate blanks containing microbial components.

[0055] (3) The modified aggregate preform containing microbial components was cultured at 40°C for 18 hours.

[0056] (4) After the modified aggregate blanks are grown, they are placed in a mineralization curing box, chemical tail gas is introduced, the temperature is 160℃, the CO2 volume concentration is 25%, and the mineralization curing is carried out for 8 hours.

[0057] The compressive strength of the carbon-fixed aggregate prepared in this embodiment is 9.6 MPa, and the CO2 solidification amount is 7.8 kg.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas, characterized in that, Multi-source solid waste is dried and ball-milled to obtain powder. The powder, alkali activator, and microbial powder are mixed evenly, and then water is added for granulation to obtain modified aggregate preforms. The modified aggregate preforms are then cultivated and cured at a temperature of 20~60 ℃. The cultivated and cured modified aggregate preforms are placed in industrial flue gas containing CO2 and mineralized and cured at a temperature of 120~200 ℃ to obtain aggregate. The multi-source solid waste is sulfuric acid residue and / or phosphorus mud; the microbial powder is *Vibrio ammoniagenicus*. Thermovibrio ammonificans The alkaline activator is one or more of carbide slag and steel slag. The mass ratio of powder, alkali activator and microbial powder is 55~80:15~35:5~10.

2. The method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas as described in claim 1, characterized in that, The drying temperature for multi-source solid waste is 110~120 ℃, and the drying time is 10~14 h.

3. The method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas as described in claim 1, characterized in that, The parameters for ball milling the dried multi-source solid waste are as follows: ball mill speed set to 180~220 r / min, turning speed set to 4~6 times / min, and ball milling time set to 20~40 min.

4. The method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas as described in claim 1, characterized in that, The powder is mixed with an alkali activator to obtain a mixture. The mixture is then mixed evenly with microbial powder and granulated with water.

5. The method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas as described in claim 4, characterized in that, During the granulation process, the mass ratio of the mixture to water is 1:0.05~0.

8.

6. The method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas as described in claim 5, characterized in that, The mass ratio of the mixture to water is 1:0.50~0.

8.

7. The method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas as described in claim 1, characterized in that, The cultivation and maintenance time is 6-18 hours.

8. The method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas as described in claim 1, characterized in that, CO2-containing industrial flue gas includes one or more of the following: cement kiln tail gas, coal gasification tail gas, and chemical tail gas.

9. The method for preparing microbial-multi-source solid waste-based aggregate for carbon sequestration in industrial flue gas as described in claim 1, characterized in that, In the aforementioned mineralization curing process, the volume concentration of carbon dioxide is 20-25%. Alternatively, the mineralization curing time is 4~10 h.

10. A microbial-based multi-source solid waste aggregate for carbon sequestration in industrial flue gas, characterized in that, Obtained by the preparation method according to any one of claims 1 to 9.

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