Microbial activation method and application of sintered brick slag powder

Abstract

The invention discloses a microbial activation method and application of sintered brick slag powder, relates to the technical field of resource recycling of building solid wastes, and aims to solve the problems of large composition difference, poor performance, low utilization rate and the like of the sintered brick slag powder. According to the microbial activation method for the sintered brick slag powder, the sintered brick slag powder is activated by adopting AS1.232 bacillus mucilaginosus, so that solubilizing activation treatment is carried out, and the sintered brick slag powder subjected to microbial activation can be used as a substitute of a common active admixture, an admixture and the like; and an efficient and low-carbon regeneration application technical approach is provided for the sintered brick slag powder.

Description

Technical Field

[0001] The invention belongs to the technical field of resource recycling of building solid waste, and specifically relates to a microbial activation method and application of sintered brick slag powder. Background Art

[0002] Sintered brick slag powder is the small-particle residue discharged after the large-particle aggregate is removed from the concrete debris generated during the demolition of old buildings. It has complex composition, low activity, and poor physical properties. It is the most difficult type of material to effectively recycle among construction solid waste. The resource recycling of sintered brick slag powder has always been an engineering and technical problem worldwide. The existing utilization methods mainly include direct backfilling, simple grinding and low-volume blending for roads or civil engineering projects, and even land storage. Its consumption efficiency is insufficient, potential exploration is lacking, and technical and economic efficiency is low. With the advancement of domestic urbanization and the rise of intelligent transformation of the construction industry, the emission pressure of construction solid waste is increasing day by day, and the contradiction between emission and consumption is becoming increasingly intensified. This urgently requires more advanced resource utilization technology and higher regeneration efficiency. In recent years, biotechnology has developed rapidly. Microorganisms can be important decomposers in nature. They play an important role in mineral materials through their own life activities and acidic metabolites. They can effectively decompose and utilize various insoluble minerals and have the effect of promoting the chemical cycle of mineral elements, such as silicon cycle. The main components of sintered brick slag powder are stable silicon and aluminum substances, which have low activity. Traditional mechanical, thermal, and chemical methods have low activation efficiency and high energy consumption, which greatly limits its recycling. Using microbial technology to dissolve and activate sintered brick slag powder, and then using it as a substitute for commonly used active mixed materials and admixtures, can not only effectively alleviate the pressure of solid waste emissions, but also improve the environmental protection and sustainable development of the construction and building materials industries. This will definitely become one of the development trends of solid waste resource utilization.

[0003] In the prior art, the activation of sintered brick slag powder has been studied more than its application, and it has problems such as low activity, high energy consumption, low absorption rate, and poor applicability. For example, Chinese patent application CN202210241659.0 provides a road repair concrete containing construction waste aggregate, and its content only involves the use of ground brick slag as an inert filler to prepare aluminate cement-based concrete materials. Chinese patent application CN201811182801.9 provides a method for preparing aerated bricks, and its content involves adding crushed sintered brick slag powder to the production of aerated bricks, and using the crystal growth of hydration products such as hydrated calcium silicate in the brick slag to form a crystal structure, shortening the time of autoclave curing, thereby improving production efficiency.

[0004] In the document "The Effect of Various Activation Mechanisms on the Activity of Sintered Brick Slag Powder" (Li Xiao et al., China Harbour Construction, 2023, No. 43 (08), 52-57), microwave, heat and chemical excitation were used to effectively improve the activity of sintered brick slag powder and realize its recycling. The literature study used traditional activation methods and did not involve relevant content of microbial activation. In the document "Study on the Preparation of Recycled Concrete Micropowder-Based Masonry Materials Based on Microbial Solubilization and Activation" (Li Xiao et al., New Building Materials, 2023, No. 50 (09), 114-117), recycled concrete micropowder was soaked in different mass concentrations of Bacillus subtilis liquid of bio-51767 for 14 days, and the influence of the strain liquid on its activity was studied. Then, recycled concrete micropowder-based masonry materials were prepared with different proportions. The strain type used in the literature research is different from that of the present invention, and the activation object is recycled concrete micropowder. The microbial activation only involves the primary strain liquid, which is a relatively basic study. There are huge differences between sintered brick slag powder and recycled concrete powder in terms of chemical composition, mineral composition and elemental existence forms. There are significant differences in the mechanism of molecular structure decomposition and destruction by microbial metabolism and activated enzymes, which cannot be achieved through simple empirical inferences, and the literature does not involve the effect of secondary reproduction on activation. In the master's thesis "Research on the Synergistic Improvement of Cementitious Properties of Circulating Fluidized Bed Fly Ash by Microbial Mineralization and Activation" (Liu Yunqi, Taiyuan University of Technology, January 2023), the activation and mineralization of circulating fluidized bed fly ash (CFA) by colloidal Bacillus (Pm) was used, and the dissolution rate of SiO2 and Al2O3 of CFA in an alkaline environment and its Ca2+ in saturated lime water were improved by carbonic anhydrase. 2+ Absorption capacity indicates that the activity of CFA volcanic ash is improved. 40% Pm is conducive to promoting CFA hydration, accelerating the early formation of calcium sulfonate and inducing biomineralization. It utilizes the high calcium characteristics of CFA and the characteristics of volcanic ash activity to improve the gelling properties of CFA-based cementitious materials, and at the same time, it can alleviate the stability problem caused by high calcium to a certain extent. The microbial strain used in this document is different from that of the present invention, and the activation object is circulating fluidized bed fly ash. Since this is a high-calcium fly ash, the activation effect of the strain liquid focuses more on accelerating Ca 2+ Consumption. The volcanic ash activity of sintered brick slag powder is much lower than that of circulating fluidized bed fly ash, and the forms of calcium in the two are very different. The crystal stability of calcium silicate and calcium aluminosilicate in sintered brick slag powder is much greater than that of calcium oxide and calcium sulfate in circulating fluidized bed fly ash, and the solubility is also lower. Therefore, the microbial solubilization and activation mechanisms of the two are quite different, and the activation difficulty of sintered brick slag powder is much greater than that of circulating fluidized bed fly ash.

[0005] In summary, most of the existing research results and papers use traditional mechanical, thermal, and chemical activation methods to enhance the activity of sintered brick slag powder, which consumes a lot of energy, is less environmentally friendly, requires a lot of equipment, and has insufficient activation effect. The objects of microbial activation are mostly recycled concrete powder or circulating fluidized bed fly ash. These substances are significantly different from sintered brick slag powder in terms of chemical composition, mineral composition, elemental form, etc., and sintered brick slag powder has a more stable structure and is more difficult to activate due to the sintering process. There is almost no research on the microbial activation of sintered brick slag powder, and no relevant technical methods have emerged. Therefore, with the resource utilization of construction solid waste and the low-carbon sustainable development of the construction industry, it is urgent to develop a biotechnology-based sintered brick slag powder activity enhancement technology to solve the technical problems of efficient, low-carbon disposal and recycling of construction solid waste. Summary of the invention

[0006] The purpose of the utility model is to provide a microbial activation method and application of sintered brick slag powder in view of the problems existing in the prior art.

[0007] To achieve the above object, the technical solution adopted by the present invention is: The first aspect of the present invention provides a method for microbial activation of sintered brick slag powder, wherein the sintered brick slag powder is activated by using Bacillus subtilis AS1.232.

[0008] The present invention uses AS1.232 Bacillus subtilis to activate sintered brick slag powder. The strain has a significant solubilizing effect on silicon, aluminum, and calcium minerals contained in the sintered brick slag powder. On the one hand, the biological acid produced by its metabolism has a corrosive decomposition effect on minerals such as quartz, feldspar, and kaolinite. On the other hand, the activated enzyme produced by it can effectively accelerate the dissolution of elements such as silicon, aluminum, and calcium. The mechanism for improving the activity of sintered brick slag powder is to transform the stable quartz and other minerals therein into an unstable state, thereby increasing the solubility in the liquid phase, and then increasing the number of them participating in the hydration reaction to form a hardened structure. The present invention also reveals the action mechanism of AS1.232 Bacillus subtilis on silicon, aluminum and calcium substances through basic research, that is, in the early stage of the secondary reproduction of the strain, the silicon, aluminum and calcium substances in the sintered brick slag powder can be effectively decomposed, and part of them are absorbed into the cell fluid. At this time, if the strain dies, its cells rupture, and the soluble silicon, aluminum and calcium elements enter the sintered brick slag powder slurry, and the drying process does not affect its ability to dissolve again; and as the life cycle of the strain progresses, the silicon, aluminum and calcium elements in the cell fluid are reconstructed to form a new cell wall tissue, and after the strain dies, the solubility of the cell wall is low, which is not conducive to increasing the concentration of silicon, aluminum and calcium in the liquid phase.

[0009] Furthermore, the particle size of the sintered brick slag powder is 400 mesh.

[0010] The present invention adopts biotechnology to recycle and utilize sintered brick slag powder, which is significantly different from other activation process methods. Among the existing activation methods: mechanical activation can improve the activity of sintered brick slag powder to a certain extent, but it is mainly a filling mechanism after particle refinement, and the efficiency of destroying its crystal structure is low. When the particle size reaches 400 mesh, the activity improvement effect of sintered brick slag powder is far lower than the application requirement, and when the particles continue to be refined, the grinding energy consumption is significantly increased. Thermal activation destroys the stable Si-O bond energy through thermal energy, thereby converting stable silicon-oxygen tetrahedrons into unsaturated structures. Minerals such as quartz in sintered brick slag powder have high chemical bond energy, and the energy required to destroy these stable structures is huge. Therefore, although thermal activation can effectively improve the activity of sintered brick slag powder, its energy consumption is huge, and the equipment requirements are relatively high, which is not conducive to low-carbon requirements. Chemical excitations such as acids, alkalis, and salts can only act on unstable active silicon and aluminum substances, but have no obvious effect on stable minerals such as quartz. Therefore, under the condition that the activity of sintered brick slag powder itself is low, chemical excitation has little effect on improving activity, and it also has pollution problems to the environment. Compared with the above activation methods, microbial activation has low requirements for equipment conditions and does not require complex and precise machinery and facilities; the secondary reproduction of microorganisms themselves can quickly increase the strain content in the liquid phase by increments, thereby improving the solubilization effect of elements such as silicon, aluminum, and calcium. Therefore, the initial strain liquid concentration is not required to be high, and the process adaptability is strong. Microbial activation completely relies on microbial reproduction, destroys bond energy through cell metabolism, has reliability and universality, and can effectively solve the problem of large differences in the composition and content of non-homologous sintered brick slag powder, and does not generate a lot of noise, and has low energy consumption. AS1.232 Bacillus subtilis itself is harmless to the human body and beneficial to the environment. It is killed in the final drying stage of sintered brick slag powder activation and converted into active substances. There is no excess emission and no other pollution to the environment.

[0011] The microbial activation method of sintered brick slag powder comprises the following steps: Step S1: Under sterile conditions, fully dissolve the AS1.232 gelatinous Bacillus lyophilis powder with a nutrient base solution, and inoculate the dissolved gelatinous Bacillus lyophilis into the nutrient base solution; Step S2: adding glass powder and culturing under constant temperature and sterile conditions to obtain a strain liquid; Step S3: after mixing the sintered brick slag powder and the strain liquid, shaking and sieve under a constant temperature condition to obtain a solid-liquid mixture; Step S4: drying the solid-liquid mixture to obtain microbially activated sintered brick slag powder.

[0012] Furthermore, in the method for microbial activation of sintered brick slag powder, the raw materials used include the following components in parts by weight: 18-22 parts of sintered brick slag powder, 78-82 parts of nutrient base liquid, 0.0005-0.0010 parts of glass powder, and 0.002-0.004 parts of AS1.232 Bacillus subtilis freeze-dried powder.

[0013] Furthermore, the nutrient base solution includes the following components in parts by weight: 0.045-0.050 parts of MgSO4•7H2O, 0.009-0.010 parts of CaSO4•2H2O, 0.18-0.20 parts of Na2HPO4, 0.00045-0.00050 parts of FeCl3, 0.45-0.50 parts of glucose, and 99.2-99.4 parts of distilled water.

[0014] Preferably, in step S1, the pH value of the nutrient base solution is 7.0±0.1.

[0015] Furthermore, in step S2, glass powder is added to make the mass concentration of AS1.232 Bacillus subtilis reach 15-25 mg / L, and culture is carried out for 3 days to obtain a strain liquid.

[0016] Furthermore, in step S3, the sintered brick slag powder and the strain solution diluted 5 to 10 times are mixed in a mass percentage ratio of 1: (4 to 5).

[0017] Furthermore, in step S3, the rotation speed of the oscillating screen is 190-230 r / min, and the oscillating screen is shaken every 4 hours for 20 minutes each time for 8 days.

[0018] Furthermore, in step S4, the solid-liquid mixture is dried at 120±5° C. to a moisture content of less than 2%, thereby completing the microbial activation of the sintered brick slag powder.

[0019] Preferably, the glass powder is soda-lime-silica glass fine powder with a particle size of 200 meshes.

[0020] Furthermore, in step S2, a portion of the strain liquid is retained to obtain the inoculated strain An, and multiple generations of inoculation are performed to obtain the strain liquid An+1, where n≤4.

[0021] It should be noted that AS1.232 Bacillus subtilis can be activated for multiple generations. After each inoculation, activation and cultivation, the inoculated strain An is retained for microbial activation for the next generation of strain inoculation. Considering the contamination and variation during the inoculation of strain generations, it is recommended that n≤4 to ensure the microbial activation effect on sintered brick slag powder.

[0022] Preferably, the above-mentioned constant temperature is 30°C.

[0023] The second aspect of the present invention provides the application of the sintered brick slag powder activated by the above method. The application scope of the sintered brick slag powder activated by microorganisms includes but is not limited to active admixtures, mineral admixtures, and raw materials for cement-based products.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses AS1.232 mucilaginous Bacillus to activate sintered brick slag powder. Compared with other mucilaginous Bacillus, the strain has a significant effect on the mineral composition and chemical composition of sintered brick slag powder. The present invention determines the microbial activation cycle to obtain the optimal solubilization and activation effect, thereby providing a new biotechnology-based activation technology approach for sintered brick slag powder.

[0025] 2. The microbial activation of the present invention has low requirements for equipment conditions and does not require complex and precise machinery and facilities; the secondary reproduction of the microorganisms themselves can quickly increase the strain content in the liquid phase by exponential increments, thereby improving the solubilization effect on elements such as silicon, aluminum, and calcium. Therefore, the initial strain liquid concentration is not required to be high, and the process adaptability is strong. Microbial activation is completely dependent on microbial reproduction, and the bond energy is destroyed through cell metabolism. It has reliability and universality, and can effectively solve the problem of large differences in the composition and content of non-homologous sintered brick slag powder, and does not generate a lot of noise, and has low energy consumption. AS1.232 Bacillus subtilis itself is harmless to the human body and beneficial to the environment. It is killed in the final drying stage of the activation of sintered brick slag powder and converted into active substances. There is no excess emission and no other pollution to the environment. Therefore, the present invention has significant advantages in terms of technical cost compared with the existing activation process, and provides a highly efficient recycling technology approach for the resource utilization of sintered brick slag powder, with significant environmental and social benefits.

[0026] 3. The present invention activates the sintered brick slag powder through biotechnology, so that its activity is reliably improved, and the technical requirements of existing active mixed materials and admixtures are met. The present invention has low requirements for the raw materials of sintered brick slag powder, good and stable activation effect, and the activated sintered brick slag powder has no deterioration effect on the technical indicators such as the setting time and stability of cement-based materials, so it can be widely used in various cement, concrete and other materials and products, solving the problem of its low activity and application limitation that it can usually only be used as a low-grade raw material filling, and has significant economic and technical benefits. DETAILED DESCRIPTION

[0027] The following will be used in conjunction with examples to explain the implementation of the present invention in detail, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention proposes a microbial activation method and application of sintered brick slag powder, using AS1.232 Bacillus subtilis, targeting the main chemical composition, mineral composition and material form of sintered brick slag powder. The sintered brick grades used in old buildings cover MU5~MU20, and their sintering raw materials include clay, shale, coal gangue, etc., and their main chemical components include silicon, aluminum, calcium and other elements, but the mineral composition and element morphology are quite different, which leads to significant differences in the composition and performance of brick slag produced by demolition, which is not conducive to direct application, and when it is activated by conventional processes such as mechanical, thermal, and chemical, the product performance fluctuates greatly. AS1.232 Bacillus subtilis was selected for microbial activation of sintered brick slag powder. On the one hand, its effect is closely related to the content of silicon, aluminum and calcium, but is not significantly affected by the existence form of silicon, aluminum and calcium. This overcomes the problem of large fluctuations in the mineral composition of sintered brick slag powder to the greatest extent; on the other hand, the biological acid and activation enzyme produced by the metabolism of this strain have a significant solubilization effect on elements such as silicon, aluminum, calcium in crystalline and amorphous forms, which can effectively improve the reaction activity of sintered brick slag powder; at the same time, this strain has strong reproduction, low variability, stable transmission, is harmless to the human body, and is beneficial to the environment.

[0029] The particle size of the sintered brick slag powder is selected to be 400 mesh. The sintered brick slag selected from the old building demolition can be ground to the required fineness by a disc crusher or a ball mill. During the crushing and preparation process of the sintered brick slag, a large number of micropores and mesopores are generated inside, and its specific surface area is significantly increased, which increases the contact area with microorganisms, thereby increasing the solubilization and activation effect. The hardness of sintered bricks is not high, so the energy consumption required to grind it to 400 mesh is relatively low, and it can meet the requirements of microbial activation. When the fineness is further increased, the particles are more likely to agglomerate, their elastic tendency increases, and the grinding efficiency is significantly reduced. Although the microbial activation effect is improved, the energy consumption is too high, which is not worth the loss.

[0030] The culture container is sterilized at 121°C for 20 minutes in a pressure steam sterilizer and cooled to room temperature for use. The culture container can be made of glass, plastic, or stainless metal.

[0031] MgSO4•7H2O, CaSO4•2H2O, Na2HPO4, FeCl3, glucose and distilled water were prepared into nutrient solution at room temperature in proportion. The pH value of the nutrient solution was adjusted to 7.0±0.1. Under a sterile environment, the nutrient solution was evenly poured onto the freeze-dried powder of AS1.232 Bacillus colloids using a pipette until the freeze-dried bacteria were fully dissolved and milky white. Then, the dissolved Bacillus colloids were inoculated into the nutrient solution, and glass powder was added to prepare a strain solution with a mass concentration of 20 mg / L in the culture container. In the strain activation stage, ordinary sodium-lime-silica glass powder was used as the source of silicon for its metabolic intake. In this process, AS1.232 Bacillus colloids was activated, and it is an aerobic bacterium with an optimal survival environment temperature of 30°C. The culture container does not need to be sealed, and can be sealed with a plastic film to prevent the entry of pollution sources and cause strain mutations. The film should be pierced with sharp objects such as toothpicks, with 1-2 holes per square centimeter. The prepared strain liquid was placed in a constant temperature sterile environment at 30°C and cultured for 3 days to obtain strain liquid I, wherein the constant temperature environment can be obtained by a constant temperature water bath and is also maintained by an air conditioning system.

[0032] The strain liquid I that has been cultured is examined under an optical microscope to confirm that the strain grows well and has no contamination or variation. A portion of the strain liquid I is retained and divided into a certain number of sterile glass or stainless metal containers according to the stock volume, and packaged with a 1:1 mass percentage glycerol-physiological saline mixture, and frozen at -18°C to obtain the inoculated strain A1, which is used for the next generation of inoculation and activation of the strain in the next round of microbial activation. AS1.232 Bacillus subtilis can be activated for multiple generations. After each inoculation, activation and cultivation, the inoculated strain An (n=1,2,3...) is retained while being used for microbial activation, so as to inoculate the next generation of strains. Considering the contamination and variation during the inoculation process of the strain generations, in order to ensure the microbial activation effect of the sintered brick slag powder, it is recommended that n≤4. If the inoculation operation environment has a high degree of sterilization, the contamination and variation of the strain can be reliably avoided, and the inoculation generation can be increased. It is recommended that the number of generations of inoculation should not exceed 4 times, because it is necessary to ensure that the strain does not produce obvious mutations and does not affect the activation effect after 4 inoculations. In this way, the sterility requirements for the working environment will not be too high, thereby reducing equipment investment.

[0033] The strain liquid I is diluted 5-10 times in a plastic or stainless metal storage tank using a nutrient base liquid to obtain a strain liquid II. After dilution with the nutrient base liquid, sufficient nutrients are provided for the strain during the required reproduction cycle. Too high a dilution multiple will lead to insufficient nutrition of the strain and reduced activity, while too low a dilution multiple will cause eutrophication, resulting in residual components of the culture medium after activation, affecting the application performance of the sintered brick slag powder. Glass powder is not added during the dilution process because the elements such as silicon required for the metabolism of the strain will be provided by the sintered brick slag powder, thereby increasing the dissolution rate of elements such as silicon, aluminum, and calcium in the sintered brick slag powder.

[0034] Mix the sintered brick slag powder and strain liquid II in a trough at a mass percentage of 1:5-1:4. At this ratio, a better microbial action efficiency and activation rate of sintered brick slag powder can be guaranteed. If the ratio is too high, the utilization efficiency of the strain liquid will be reduced, and due to the reduction in the content of silicon elements, the strain activity will be reduced, and the nutrient base liquid components will remain; if the ratio is too low, the sintered brick slag powder will settle and aggregate at the bottom of the trough, which is not conducive to the effective contact between the strain and the sintered brick slag powder, thereby reducing the activation efficiency. The shape and capacity of the trough are selected according to the equipment conditions, and the surface is sealed with gauze. Then fix it on the shaking screen machine, according to the working system of 190-230 r / min, shaking and sieving once every 4 hours, 20 minutes each time, and 30°C ambient temperature, intermittent shaking and sieving for 8 days to obtain a solid-liquid mixture. If the intermittent oscillation and shaking cycle is too short, it will not be conducive to the effective decomposition of silicon, aluminum and calcium substances in the sintered brick slag powder by the secondary reproduction of the strain, and the solubilization and activation effect will be poor; if the cycle is too long, the silicon, aluminum and calcium elements in the cell fluid of the strain will reconstruct into new cell wall tissue, and after the strain dies, the solubility of the cell wall will be low, thereby reducing the effective dissolution rate of silicon, aluminum and calcium elements.

[0035] The solid-liquid mixture is dried at 120±5℃ to a moisture content of less than 2% to complete the microbial activation of the sintered brick slag powder. At this point, the components in the nutrient base liquid are basically consumed and will not affect the performance of the sintered brick slag powder. During the drying process, the strain dies at high temperature, its cell wall ruptures and shrinks, and the soluble silicon, aluminum, and calcium elements it absorbs precipitate into the liquid phase with the cell fluid, increasing the ion concentration in the liquid phase. As the drying proceeds, the silicon, aluminum, and calcium elements in the liquid phase reprecipitate, but when water is added and mixed again, they can still be dissolved, thereby increasing the reactivity of the sintered brick slag powder. When the moisture content of the sintered brick slag powder is lower than 2%, it is not easy to agglomerate, which is convenient for its storage and transportation.

[0036] In some examples, the raw materials used in the method for microbial activation of sintered brick slag powder include the following components in parts by weight: 18-22 parts of sintered brick slag powder, 78-82 parts of nutrient base liquid, 0.0005-0.0010 parts of glass powder, and 0.002-0.004 parts of AS1.232 Bacillus subtilis freeze-dried powder.

[0037] In some examples, the nutrient base solution includes the following components in parts by weight: 0.045-0.050 parts of MgSO4•7H2O, 0.009-0.010 parts of CaSO4•2H2O, 0.18-0.20 parts of Na2HPO4, 0.00045-0.00050 parts of FeCl3, 0.45-0.50 parts of glucose, and 99.2-99.4 parts of distilled water.

[0038] In the following examples and comparative examples, the raw material types and parameters used are as follows: P.O42.5 grade cement: 28d compressive strength is 45.3 MPa, purchased from Liaoning Shanshui Cement Co., Ltd.; Sintered brick slag powder: Made from construction waste bricks generated from the demolition site of old houses in the old city of Shenyang, Liaoning Province, after crushing, screening and processing, purchased from Shenyang Zhongcheng Urban Mineral Resources Development Group Co., Ltd.; AS1.232 Bacillus mucilaginosus lyophilized powder: purchased from Shanghai Preservation Biotechnology Center; bio-51767 Bacillus mucilaginosus: purchased from Zhili Zhongte (Wuhan) Biotechnology Co., Ltd.; Glass powder: Made by grinding ordinary soda-lime-silica flat glass; MgSO4•7H2O: chemical reagent, analytical grade, purchased from Shenyang Jindu Laboratory Equipment Company; CaSO4•2H2O: chemical reagent, analytical grade, purchased from Shenyang Jindu Laboratory Equipment Company; FeCl3: chemical reagent, analytical grade, purchased from Shenyang Jindu Laboratory Equipment Company; Glucose: chemical reagent, analytical grade, purchased from Shenyang Jindu Laboratory Equipment Company; Distilled water: purchased from Shenyang Jindu Laboratory Equipment Company; K2HPO4: chemical reagent, analytical grade, purchased from Shenyang Jindu Laboratory Equipment Company; NaCl: chemical reagent, analytical grade, purchased from Shenyang Jindu Laboratory Equipment Company; Beef paste: purchased from Shenyang Jindu Laboratory Equipment Company; Yeast extract: purchased from Beijing Aoboxing Biotechnology Co., Ltd.; Peptone: purchased from Beijing Aoboxing Biotechnology Co., Ltd.

[0039] The 28d activity index test of microbially activated sintered brick slag powder in the implementation and comparative examples was determined according to the method requirements in Appendix D of GB / T1596-2005 "Fly ash used in cement and concrete"; the setting time and volume stability tests of cement-sintered brick slag powder slurry were determined according to the requirements of GB / T 1346 "Test methods for water consumption, setting time and stability of cement standard consistency", wherein the cement-sintered brick slag powder slurry included the following components by weight: 53.8 parts of P.O42.4 grade cement, 23.1 parts of sintered brick slag powder, and 23.1 parts of water; the water demand ratio test of sintered brick slag powder was determined according to the requirements of GB / T 1596 "Fly ash used in cement and concrete". Example 1

[0040] The raw materials used in the microbial activation method of sintered brick slag powder provided in this embodiment include the following components in parts by weight: 18 parts of 400-mesh sintered brick slag powder, 81.995 parts of nutrient base liquid, 0.0008 parts of 200-mesh glass powder, and 0.004 parts of AS1.232 gelatinous Bacillus freeze-dried powder.

[0041] The glass powder is soda-lime-silica glass powder.

[0042] The nutrient base solution includes the following components in parts by weight: 0.050 parts of MgSO4•7H2O, 0.010 parts of CaSO4•2H2O, 0.18 parts of Na2HPO4, 0.00050 parts of FeCl3, 0.50 parts of glucose, and 99.2595 parts of distilled water.

[0043] The steps of microbial activation of sintered brick slag powder are: Step S1: The culture container is first sterilized at 121°C for 20 minutes in a pressure steam sterilizer and cooled to room temperature. The pH value of the nutrient solution is adjusted to 7.0. Under a sterile environment, the nutrient solution is evenly poured into the AS1.232 gelatinous Bacillus freeze-dried powder using a pipette until the freeze-dried bacteria are fully dissolved and milky white. The dissolved gelatinous Bacillus is inoculated into the nutrient solution; Step S2, adding glass powder to make the mass concentration of AS1.232 Bacillus mucilaginosus reach 20 mg / L, and culturing in a 30°C constant temperature sterile environment for 3 days to obtain strain liquid I; Step S3, retaining part of the strain liquid I, encapsulating it with a glycerol-physiological saline mixture with a mass percentage of 1:1, and freezing it at -18°C to obtain the inoculated strain A1 for the next generation of secondary strain inoculation, and diluting the remaining strain liquid I by 10 times with a nutrient base liquid to obtain strain liquid II; Step S4, after mixing the sintered brick slag powder and the strain liquid II in a mass percentage of 1:4, intermittently shaking and sieving at a constant temperature of 30° C. at a speed of 190 r / min, 4 h / time, each time for 20 min for 8 days to obtain a solid-liquid mixture; Step S5, drying the solid-liquid mixture at 120±5° C. to a moisture content of 1.9%, completing the microbial activation of the sintered brick slag powder, and obtaining microbial activated sintered brick slag powder. Example 2

[0044] The microbial activation method of sintered brick slag powder uses raw materials including the following components in parts by weight: 22 parts of 400-mesh sintered brick slag powder, 77.9975 parts of nutrient base liquid, 0.0005 parts of 200-mesh glass powder, and 0.002 parts of AS1.232 gelatinous Bacillus freeze-dried powder.

[0045] The glass powder is soda-lime-silica glass powder.

[0046] The nutrient base solution includes the following components in parts by weight: 0.045 parts of MgSO4•7H2O, 0.009 parts of CaSO4•2H2O, 0.20 parts of Na2HPO4, 0.00045 parts of FeCl3, 0.45 parts of glucose, and 99.29555 parts of distilled water.

[0047] The method for activating sintered brick slag powder microorganisms provided in this embodiment is different from that in Example 1 in that in step S3, the remaining strain liquid I is diluted 5 times with a nutrient base liquid to obtain strain liquid II; in step S4, the sintered brick slag powder and strain liquid II are mixed in a mass percentage of 1:5, and the intermittent oscillation speed is 200 rpm / min; in step S5, the solid-liquid mixture is dried at 120±5°C to a moisture content of 1.5%. Example 3

[0048] The method for activating sintered brick slag powder microorganisms provided in this embodiment is different from that in Example 1 in that the nutrient base liquid in step S1 of this embodiment activates the inoculated strain A1, and the intermittent oscillation speed in step S4 is 200 rpm / min. Example 4

[0049] The method for microbial activation of sintered brick slag powder provided in this embodiment is different from that in Embodiment 1 in that the nutrient base liquid in step S1 activates the inoculated strain A2, and the intermittent oscillation speed in step S4 is 210 rpm / min. Example 5

[0050] The method for microbial activation of sintered brick slag powder provided in this embodiment is different from that in Embodiment 1 in that the nutrient base liquid in step S1 activates the inoculated strain A3, and the intermittent oscillation speed in step S4 is 220 rpm / min. Example 6

[0051] The method for microbial activation of sintered brick slag powder provided in this embodiment is different from that in embodiment 1 in that the nutrient base liquid in step S1 activates the inoculated strain A4, and the intermittent oscillation speed in step S4 is 230 rpm / min. Comparative Example 1

[0052] The raw materials used in the microbial activation method of sintered brick slag powder provided in this comparative example include the following components in parts by weight: 18 parts of 400-mesh sintered brick slag powder, 81.9952 parts of nutrient base liquid, 0.0008 parts of 200-mesh glass powder, and 0.004 parts of bio-51767 Bacillus subtilis.

[0053] The glass powder is soda-lime-silica glass powder.

[0054] The nutrient base solution includes the following components in parts by weight: 0.050 parts of MgSO4•7H2O, 0.010 parts of CaSO4•2H2O, 0.18 parts of Na2HPO4, 0.00050 parts of FeCl3, 0.50 parts of glucose, and 99.2595 parts of distilled water.

[0055] The sintered brick slag powder microbial activation step provided in this comparative example is different from that in Example 1 in that the nutrient base liquid in step S1 of this comparative example activates Bacillus subtilis bio-51767, and the other raw material components and weights remain unchanged. Comparative Example 2

[0056] The raw materials used in the microbial activation method of sintered brick slag powder provided in this comparative example include the following components in parts by weight: 18 parts of 400-mesh sintered brick slag powder, 81.9952 parts of nutrient base liquid, 0.0008 parts of 200-mesh glass powder, and 0.004 parts of AS1.232 gelatinous Bacillus freeze-dried powder.

[0057] The nutrient base liquid comprises the following components in parts by weight: 0.5 parts of yeast extract, 3 parts of beef extract, 0.2 parts of K2HPO4, 5 parts of NaCl, 10 parts of peptone, and 76.8 parts of distilled water, and other raw material components and weights remain unchanged.

[0058] The other steps of the method for microbial activation of sintered brick slag powder provided in this comparative example are the same as those in Example 1. Comparative Example 3

[0059] The method for microbial activation of sintered brick slag powder provided in this comparative example is different from that in Example 1 in that the nutrient base liquid in step S1 of this comparative example activates the inoculated strain A5, and the intermittent oscillation speed in step S4 is 230 rpm / min. Application Examples

[0060] Performance evaluation of the sintered brick slag powder activated by microorganisms in the above examples and comparative examples: The test results of its 28d activity index, cement-sintered brick slag powder paste setting time, cement-sintered brick slag powder volume stability, and water demand ratio are shown in Table 1 below:

[0061] Combined with the test results in the above table, by comparing Examples 1-2, it can be seen that within the range, changing the dosage of AS1.232 Bacillus colloidalis freeze-dried powder and the dilution multiple of the nutrient base liquid will affect the 28d activity index of sintered brick slag powder and the setting time of cement-sintered brick slag powder slurry. By comparing Examples 1, 3, 4, 5, and 6, it can be seen that changing the AS1.232 Bacillus colloidalis generation has a significant effect on the 28d activity index of sintered brick slag powder.

[0062] By comparing Example 1 and Comparative Examples 1-3, it can be determined that the use of Bacillus gelatinus of bio-51767 to replace Bacillus gelatinus of AS1.232 will have a significant adverse effect on the 28d activity index of sintered brick slag powder, and will have a certain effect on the coagulation time and water requirement ratio. The use of different nutrient base liquids will have a significant adverse effect on the 28d activity index of sintered brick slag powder, and will have a certain effect on the coagulation time and water requirement ratio. Under the conditions described in the invention, when the AS1.232 Bacillus gelatinus inoculation generation reaches 5 times, it has a significant adverse effect on the 28d activity index of sintered brick slag powder, and has a greater impact on the coagulation time and water requirement ratio, while the intermittent oscillation speed increase has little effect on the 28d activity index of sintered brick slag powder.

[0063] This all shows that AS1.232 Bacillus mucilaginosus, inoculation generations and nutrient base liquid formula are irreplaceable in the sintered brick slag powder microbial activation method of the present invention. Among them, AS1.232 Bacillus mucilaginosus has a significant solubilization and activation effect on silicon, aluminum and calcium elements in the form of crystals in sintered brick slag powder, thereby having a positive effect on the 28d activity index of sintered brick slag powder, and has no significant adverse effect on indicators such as cement-sintered brick slag powder slurry coagulation time, cement-sintered brick slag powder volume stability, and water demand ratio. The inoculation generations of AS1.232 Bacillus mucilaginosus can affect the degree of contamination and variation of the strain, thereby affecting the solubilization and activation effect of the strain liquid on sintered brick slag powder. The nutrient base liquid can ensure the activation rate and normal metabolic reproduction of AS1.232 Bacillus mucilaginosus, thereby ensuring the solubilization and activation effect of the strain liquid on sintered brick slag powder and improving its 28d activity index.

[0064] Although the embodiments of the present invention have been shown and described, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for microbial activation of sintered brick slag powder, characterized in that: Bacillus subtilis AS1.232 was used to activate sintered brick slag powder.

2. The method for microbial activation of sintered brick slag powder according to claim 1, characterized in that: The following steps are involved: Step S1: Under sterile conditions, fully dissolve the AS1.232 gelatinous Bacillus lyophilis powder with a nutrient base solution, and inoculate the dissolved gelatinous Bacillus lyophilis into the nutrient base solution; Step S2: adding glass powder and culturing under constant temperature and sterile conditions to obtain a strain liquid; Step S3: after mixing the sintered brick slag powder and the strain liquid, shaking and sieve under a constant temperature condition to obtain a solid-liquid mixture; Step S4: drying the solid-liquid mixture to obtain microbially activated sintered brick slag powder.

3. The method for microbial activation of sintered brick slag powder according to claim 2, characterized in that: The raw materials used in the method include the following components in parts by weight: 18-22 parts of sintered brick slag powder, 78-82 parts of nutrient base liquid, 0.0005-0.0010 parts of glass powder, and 0.002-0.004 parts of AS1.232 gelatinous bacillus freeze-dried powder.

4. The method for microbial activation of sintered brick slag powder according to claim 2, characterized in that: In the step S2, after adding glass powder, the mass concentration of AS1.232 Bacillus subtilis is 15-25 mg / L, and the culture is carried out for 3 days to obtain a strain liquid; in the step S3, the sintered brick slag powder and the strain liquid diluted 5 to 10 times are mixed in a mass percentage ratio of 1: (4 to 5).

5. The method for microbial activation of sintered brick slag powder according to claim 2, characterized in that: The nutrient base solution comprises the following components in parts by weight: 0.045-0.050 parts of MgSO4•7H2O, 0.009-0.010 parts of CaSO4•2H2O, 0.18-0.20 parts of Na2HPO4, 0.00045-0.00050 parts of FeCl3, 0.45-0.50 parts of glucose, and 99.2-99.4 parts of distilled water.

6. The method for microbial activation of sintered brick slag powder according to claim 2, characterized in that: The rotation speed of the oscillating screen in step S3 is 190-230 r / min, and the oscillating screen is shaken for 4 hours / time, 20 minutes each time, for 8 days.

7. The method for microbial activation of sintered brick slag powder according to claim 2, characterized in that: In the step S4, the solid-liquid mixture is dried at 120±5° C. to a moisture content of less than 2%, thereby completing the microbial activation of the sintered brick slag powder.

8. The method for microbial activation of sintered brick slag powder according to claim 2, characterized in that: The particle size of the sintered brick slag powder is 400 meshes, and the glass powder is soda-lime-silica glass fine powder with a particle size of 200 meshes.

9. The method for microbial activation of sintered brick slag powder according to claim 2, characterized in that: In the step S2, a portion of the strain liquid is retained to obtain the inoculated strain An, and the strain liquid An+1 is obtained by performing generation inoculation, where n≤4.

10. Application of sintered brick slag powder activated by the method according to any one of claims 1 to 9, characterized in that: The application scope of the microbially activated sintered brick slag powder includes but is not limited to active admixtures, mineral admixtures, and raw materials for cement-based products.

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