Efficient coal gangue aggregate modification method and device based on microbial mineralization technology

Abstract

The invention relates to an efficient coal gangue aggregate modification method and device based on a microbial mineralization technology. The method comprises the following steps: selecting a mineralized microbial strain: selecting a mixed bacterium of bacillus pasteurii and bacillus coelii as the mineralized microbial strain; forming a microbial mineralization system; pretreating the coal gangue; dynamic mineralization treatment: immersing the coal gangue aggregate into a microbial mineralization system, placing a coal gangue aggregate suspension, and ensuring that the bottom of the coal gangue aggregate is suspended; maintaining the mineralizing solution in a circular flow state, so that the mineralizing solution can be in full contact with the surface of the aggregate and permeate into internal pores, and maintaining the circular flow state of the mineralizing solution for 5-10 days; and cleaning and drying. According to the method, continuous circulating flow of the mineralizing solution on the surface of the coal gangue aggregate and in internal pores is achieved through the power circulating system, formation of a biological membrane in the static soaking process is effectively avoided, the penetration depth and deposition uniformity of the mineralizing solution are improved, and the method has good industrial application prospects.

Description

Technical Field

[0001] The present application belongs to the technical field of comprehensive utilization of solid waste, and specifically relates to a method and device for efficiently modifying coal gangue aggregate based on microbial mineralization technology. Background Art

[0002] Coal gangue is one of the main solid wastes generated during coal mining and washing. Its long-term accumulation not only occupies a large amount of land resources, but also may cause serious pollution to the surrounding ecological environment, such as soil pollution, water pollution and air pollution. In addition, heavy metal elements in coal gangue are easily precipitated under rain erosion or weathering, posing a potential threat to the ecosystem and human health.

[0003] Traditional methods of treating coal gangue mainly include landfill, stockpiling and direct utilization, but these methods have significant drawbacks. Landfill and stockpiling not only occupy land resources, but may also cause soil and groundwater pollution; direct use of coal gangue as concrete aggregate is limited by its physical properties, such as low hardness and high water absorption, which makes it difficult to meet the requirements of building materials.

[0004] With the improvement of environmental awareness and the increasing demand for sustainable development, researchers have gradually turned their attention to the resource utilization and high-value utilization of coal gangue. In recent years, microbial induced calcium carbonate deposition technology (MICP) has gradually attracted attention as a green, environmentally friendly and low-cost modification method. This technology uses the enzyme catalysis produced by microorganisms during metabolism to deposit calcium carbonate on the surface and internal pores of coal gangue to form a hard mineralized layer. This mineralized deposition can not only effectively fix heavy metal elements in coal gangue and reduce environmental risks, but also significantly improve the physical and mechanical properties of coal gangue and broaden its application areas.

[0005] However, there are still many technical bottlenecks in the existing technology when applying microbial mineralization technology to modify coal gangue. First, the mineralization ability and modification efficiency of a single strain of bacteria are low, and its adaptability to environmental conditions is limited, making it difficult to better promote the mineralization deposition process and improve the modification efficiency.

[0006] Secondly, the traditional static immersion method easily forms a biofilm on the surface of coal gangue. This biofilm will gradually thicken as the microbial metabolism proceeds, making it difficult for the subsequent mineralization solution to penetrate into the internal pores of the coal gangue, significantly hindering the deep contact of the bacterial solution, causing calcium carbonate deposition to concentrate on the surface, resulting in uneven mineralization. This limitation affects the thickness and penetration depth of the mineralized deposition layer, making it difficult to effectively improve the overall physical and mechanical properties of coal gangue aggregate.

[0007] Finally, when the gangue is placed directly at the bottom of the container, the bottom of the aggregate has poor contact with the mineralizing solution, especially in a static environment, where the solution in the bottom area is difficult to circulate fully, thus limiting the uniform coverage of the solution on the surface of the aggregate. In addition, poor bottom contact will lead to a weakened mineralization effect in this area and an uneven deposition layer, which will ultimately affect the overall consistency of the modification effect and the structural stability of the aggregate, making it difficult to meet the high performance requirements of building materials for aggregates.

[0008] In view of the above technical bottlenecks, the existing modification methods of coal gangue aggregates urgently need to be further optimized. Summary of the invention

[0009] The present application provides a highly efficient gangue aggregate modification method and device based on microbial mineralization technology, aiming to solve the problems of uneven gangue mineralization effect and low modification efficiency in the prior art.

[0010] In order to achieve the above purpose, the technical solution of this application is as follows:

[0011] In a first aspect, the present invention provides an efficient coal gangue aggregate modification method based on microbial mineralization technology, the method comprising:

[0012] Select mineralizing microorganism strains: select a mixed strain of Bacillus pasteurianus and Bacillus coli as mineralizing microorganism strains;

[0013] Forming a microbial mineralization system: fully mixing urea, calcium source and nutrients in pure water to prepare a mineralization solution, inoculating the mineralizing microbial strain into the mineralization solution, adjusting the pH value of the mineralization solution to 8.5-10, and maintaining the temperature of the mineralization solution at 25-35° C. to form a microbial mineralization system suitable for microbial growth;

[0014] Pretreatment of coal gangue: crush the coal gangue into particles with a particle size of 5-20mm and screen them to obtain coal gangue aggregate with uniform particle size;

[0015] Dynamic mineralization treatment: immersing the gangue aggregate in the microbial mineralization system, and placing the gangue aggregate on a suspension rack to ensure that the bottom of the gangue aggregate is suspended; maintaining the mineralization solution in a circulating flow state, so that the mineralization solution can fully contact the aggregate surface and penetrate into the internal pores, avoiding the accumulation of biofilm on the surface of the gangue aggregate, and hindering the subsequent mineralization solution from penetrating into the aggregate; maintaining the circulating flow state of the mineralization solution for 5-10 days, forming calcium carbonate precipitation on the surface of the gangue aggregate and in the internal pores;

[0016] Washing and drying: The calcium carbonate-deposited gangue particles are removed from the mineralizing solution, rinsed with pure water, and then dried to constant weight in a drying equipment.

[0017] Furthermore, the nutrient components include tryptone, yeast powder, sodium chloride and glucose;

[0018] The mass ratio of the nutrients to urea is as follows:

[0019] Tryptone: 5-15 copies

[0020] Yeast powder: 2-8 parts

[0021] Sodium chloride: 2-8 parts

[0022] Glucose: 0.5-3 parts

[0023] Urea: 10-30 parts.

[0024] Furthermore, the calcium source includes calcium nitrate, calcium acetate or calcium chloride, and the calcium ion concentration is 0.15-0.25 mol / L.

[0025] Furthermore, the concentration of the mineralized microbial strain is 2.6×10 8 cells / ml-4.3×10 9 cells / ml.

[0026] Furthermore, in parts by mass, the ratio of tryptone: yeast powder: NaCl: glucose: urea is 10:5:5:1:20.

[0027] Furthermore, the circulation flow direction of the mineralization solution is reversed every 2-5 hours.

[0028] In a second aspect, the present invention provides an efficient coal gangue aggregate modification device based on microbial mineralization technology, the device comprising:

[0029] Container body: The container body is a rectangular structure used to contain mineralizing solution and coal gangue aggregate;

[0030] Gangue aggregate suspension: the gangue aggregate suspension is horizontally arranged in the container body, and a plurality of through holes are evenly distributed on the gangue aggregate suspension. The gangue aggregate suspension is used to suspend the gangue aggregate in the air so that the bottom of the gangue aggregate maintains a distance from the bottom of the container;

[0031] Bacterial liquid power circulation system: including a circulation pipeline and a circulation pump, the bacterial liquid power circulation system is used to drive the mineralization solution to continuously circulate in the container;

[0032] Temperature control system: The temperature control system is arranged in the container body, including a temperature sensor and a heating device, and the temperature control system is used to maintain the temperature of the mineralization solution.

[0033] Furthermore, it also includes:

[0034] Reverse flow control device: The reverse flow control device is arranged in the circulation pump, and includes a timing controller. The timing controller drives the circulation pump to reverse within a preset time interval, changes the flow direction of the mineralizing solution, and realizes the periodic forward and reverse flow of the mineralizing solution in the container body.

[0035] Furthermore, a longitudinal grid is provided in the container body, and the longitudinal grid divides the container body into a guide area and a reaction area, and the gangue aggregate suspension is arranged in the reaction area.

[0036] Furthermore, the distance between the gangue aggregate suspension and the bottom of the container body is 1 / 4 of the height of the container.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present application adopts a mixed bacterial liquid system of Bacillus pasteurianus and Bacillus coli to give full play to the synergistic effect of the two bacterial species in mineralization efficiency, environmental adaptability and heavy metal fixation ability, and significantly improve the efficiency and uniformity of calcium carbonate deposition; the power circulation system is used to realize the continuous circulation flow of the mineralized solution on the surface and internal pores of the gangue aggregate, effectively avoiding the formation of biofilm during static immersion, and improving the penetration depth and deposition uniformity of the mineralized solution; the suspended placement design is adopted to separate the gangue aggregate from the bottom of the container, ensuring that the mineralized solution can cover the aggregate surface at multiple angles and penetrate into the internal pores, solving the problem of poor bottom contact; combined with the temperature control system and the reverse flow control device, the temperature and pH value of the mineralization environment are further stabilized, the uniformity and controllability of the solution flow are enhanced, and finally the physical and mechanical properties of the mineralized gangue aggregate are significantly improved, its water absorption rate and porosity are reduced, and the heavy metal elements therein are effectively fixed, which has good prospects for industrial application.

[0039] Of course, the implementation of the various technical solutions of the present application does not necessarily require achieving all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, drawings of other embodiments can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 It is a method flow chart of an embodiment of the present application.

[0042] Figure 2 This is a schematic diagram of a power bacteria liquid circulation device according to an embodiment of the present application;

[0043] In the figure, 1-container body, 101-longitudinal grid, 2-coal gangue aggregate suspension, 301-circulation pump, 302-circulation pipeline, 303-diversion nozzle device, 4-coal gangue aggregate. DETAILED DESCRIPTION

[0044] The present application is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0045] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0046] Embodiment 1:

[0047] An efficient method for modifying gangue coarse aggregate based on microbial mineralization technology, the steps are as follows:

[0048] Step 1: Select the mineralizing microorganisms

[0049] A mixed strain of Bacillus pasteurianus and Bacillus coli was selected as the mineralizing microbial strains, and the urease produced during their metabolism was used to catalyze the decomposition of urea to generate ammonia and carbon dioxide, which further reacted with calcium ions to form calcium carbonate deposits.

[0050] In this embodiment, the mixed bacteria of Bacillus pasteurianus and Bacillus columbinis have significant synergistic advantages in the microbial mineralization process; Bacillus pasteurianus is known for its efficient urease activity, which can quickly catalyze the decomposition of urea to generate carbonate ions, providing sufficient carbonate sources for calcium carbonate deposition; Bacillus columbinis has excellent adaptability in high salinity and high alkalinity environments, and can maintain stable activity when the conditions of the mineralization solution fluctuate; in addition, Bacillus columbinis has good adsorption and fixation capabilities for heavy metal ions, and its metabolites can form stable mineral precipitations with heavy metal ions, further improving the environmental protection and safety of the coal gangue modification process; the mixed use of the two strains can simultaneously exert the high mineralization efficiency of Bacillus pasteurianus and the environmental tolerance and heavy metal fixation capabilities of Bacillus columbinis, thereby forming a synergistic effect and significantly optimizing the uniformity, density and mechanical properties of the mineralized sediment layer.

[0051] Step 2: Formation of microbial mineralization system

[0052] Urea, tryptone, yeast powder, sodium chloride and glucose were dissolved in pure water in the proportion of 30 parts, 15 parts, 8 parts, 8 parts and 3 parts by mass, respectively, and 0.25 mol / L calcium acetate was added to prepare a mineralization solution; the mixed bacteria were inoculated into the mineralization solution, and the bacterial solution concentration was 2.6×10 8 The pH value of the mineralization solution was adjusted to 10 and the temperature was controlled at 35°C.

[0053] The optimal ratio of mixed bacteria was determined by mass measurement and microstructural analysis of the deposited calcium carbonate. In this embodiment, the ratio of Bacillus pasteurianus and Bacillus coli was 1:1, and the two strains were inoculated in the mineralization solution. The concentration of the two strains was 1.3×10 8 cells / ml.

[0054] Step 3: Pre-treating the gangue

[0055] The coal gangue is crushed into particles with a particle size range of 20 mm using a crusher, and then sieved to obtain coal gangue aggregate with uniform particle size.

[0056] Step 4: Dynamic mineralization treatment

[0057] Aggregate suspension placement: Suspend the gangue aggregate on the aggregate rack, keeping a distance of 1 / 4 of the container height from the bottom of the container.

[0058] Power circulation system: The mineralizing solution is kept flowing continuously on the aggregate surface and in the pores through the circulation pipe and circulation pump, and the flow direction is reversed every 2 hours.

[0059] Temperature control system: The temperature of the mineralization solution is maintained at 35°C and the mineralization time is 5 days.

[0060] Step 5: Wash and Dry

[0061] After the mineralization treatment is completed, the gangue aggregate is taken out from the mineralization solution, rinsed with pure water to remove the residual solution and bacterial liquid on the surface, and then dried to constant weight in a drying equipment to obtain modified gangue.

[0062] Embodiment 2:

[0063] An efficient method for modifying gangue coarse aggregate based on microbial mineralization technology, the steps are as follows:

[0064] Step 1: Select the mineralizing microorganisms

[0065] A mixed strain of Bacillus pasteurianus and Bacillus coli was selected as the mineralizing microorganisms. Bacillus pasteurianus produces urease during metabolism, which can catalyze the decomposition of urea to produce ammonia and carbon dioxide, and the carbon dioxide further reacts with calcium ions to form calcium carbonate precipitation.

[0066] Step 2: Formation of microbial mineralization system

[0067] Urea, tryptone, yeast powder, sodium chloride and glucose were dissolved in pure water in the proportion of 20 parts, 10 parts, 5 parts, 5 parts and 1 part by mass, and 0.20 mol / L calcium nitrate (calcium source) was added to prepare a mineralization solution; the mixed bacteria were inoculated into the mineralization solution, and the bacterial solution concentration was controlled at 3.2×10 7 The pH value of the mineralization solution was adjusted to 9.5 and the temperature was controlled at 30°C to form an environment suitable for microbial growth and mineralization deposition.

[0068] The optimal ratio of mixed bacteria was determined by mass measurement and microstructural analysis of the deposited calcium carbonate. In this embodiment, the ratio of Bacillus pasteurianus to Bacillus coli was 3:1, and the concentration of Bacillus pasteurianus in the mixed bacteria inoculated in the mineralization solution was 2.4×10 8 cells / ml, the concentration of Bacillus spp. is 0.8×10 8 cells / ml.

[0069] Step 3: Pre-treating the gangue

[0070] Coal gangue from coal mines in Ordos City, Inner Mongolia was selected and crushed into particles with a size of 10 mm using a jaw crusher. The particles were then sieved to obtain coal gangue aggregate with uniform particle size.

[0071] Step 4: Dynamic mineralization treatment

[0072] The pretreated gangue aggregate is placed in a power bacterial liquid circulation device, which comprises a suspended gangue aggregate rack, a bacterial liquid power circulation system and a temperature control system.

[0073] Aggregate suspension placement: Suspend the gangue aggregate horizontally on the aggregate rack to keep a distance between the bottom of the aggregate and the bottom of the container to avoid direct contact with the bottom.

[0074] Power circulation system: The mineralizing solution is continuously circulated on the surface and internal pores of the gangue aggregate through the circulation pipe and circulation pump to avoid the formation of biofilm during static immersion, while promoting the bacterial solution to evenly cover the surface of the aggregate and penetrate into the internal pores; the flow direction of the mineralizing solution is reversed every 3 hours.

[0075] Temperature control system: The temperature of the mineralization solution is maintained at 30°C by a temperature control device. The mineralization treatment time is 7 days.

[0076] Step 5: Wash and Dry

[0077] After the mineralization treatment is completed, the gangue aggregate is taken out from the mineralization solution, rinsed with pure water to remove the residual solution and bacterial liquid on the surface, and then dried to constant weight in a drying equipment to obtain modified gangue.

[0078] Embodiment 3:

[0079] An efficient method for modifying gangue coarse aggregate based on microbial mineralization technology, the steps are as follows:

[0080] Step 1: Select the mineralizing microorganisms

[0081] A mixed strain of Bacillus pasteurianus and Bacillus coli was selected as the mineralizing microbial strains. During their metabolism, urease was produced to catalyze the decomposition of urea to generate ammonia and carbon dioxide, which further combined with calcium ions to form calcium carbonate deposits.

[0082] Step 2: Formation of microbial mineralization system

[0083] Urea, tryptone, yeast powder, sodium chloride and glucose were dissolved in pure water in the proportion of 10 parts, 5 parts, 2 parts, 2 parts and 0.5 parts by mass, and 0.15 mol / L calcium chloride was added to prepare a mineralization solution; the mixed bacteria were inoculated into the mineralization solution, and the bacterial solution concentration was 4.3×10 9 The pH value of the mineralization solution was adjusted to 8.5 and the temperature was controlled at 25°C.

[0084] The optimal ratio of mixed bacteria was determined by mass measurement and microstructural analysis of the deposited calcium carbonate. In this embodiment, the ratio of Bacillus pasteurianus to Bacillus coli was 3:2, and the concentration of Bacillus pasteurianus in the mixed bacteria inoculated in the mineralization solution was 2.58×10 8 cells / ml, the concentration of Bacillus spp. was 1.72×10 8 cells / ml. Step 3: Pretreatment of coal gangue

[0085] The coal gangue is crushed into a particle size range of 5 mm using a crusher, and then sieved to obtain coal gangue aggregate with uniform particle size.

[0086] Step 4: Dynamic mineralization treatment

[0087] Aggregate suspension placement: Suspend the gangue aggregate on the aggregate rack, keeping a distance of 1 / 4 of the container height from the bottom of the container.

[0088] Power circulation system: The mineralizing solution is kept flowing on the aggregate surface and in the pores through the circulation pipe and circulation pump, and the flow direction is reversed every 5 hours.

[0089] Temperature control system: The temperature of the mineralization solution is maintained at 25°C and the mineralization time is 10 days.

[0090] Step 5: Wash and Dry

[0091] After the mineralization treatment is completed, the gangue aggregate is taken out from the mineralization solution, rinsed with pure water to remove the residual solution and bacterial liquid on the surface, and then dried to constant weight in a drying equipment to obtain modified gangue.

[0092] The surface of the coal gangue aggregate after mineralization treatment forms a uniform calcium carbonate deposition layer, which significantly reduces the porosity, reduces the water absorption rate, and significantly improves the mechanical properties. At the same time, the heavy metal elements in the coal gangue are effectively fixed. The modified aggregate has good physical properties and environmental friendliness and can be used as a high-performance building material.

[0093] Test example:

[0094] The unmodified coal gangue aggregate in Example 1 was used as a control group.

[0095] Table 1 shows the test results of water absorption, crushing index, apparent density and solidification rate of heavy metal elements of the embodiment and the control group.

[0096] Table 1 Water absorption, crushing index, apparent density and solidification rate of heavy metal elements of the embodiment and the control group

[0097]

[0098]

[0099] According to the test results in Table 1, the modification according to the scheme of the present invention can significantly improve the apparent density of the gangue, the solidification rate of heavy metal elements, and reduce the water absorption rate and crushing index.

[0100] Embodiment 4:

[0101] See also Figure 2This embodiment discloses a high-efficiency gangue aggregate modification device based on microbial mineralization technology, referred to as a power bacterial liquid circulation device; the device mainly includes a container body 1, a gangue aggregate suspension 2, and a bacterial liquid power circulation system.

[0102] Container body 1: The container body adopts a rectangular structure, which is used to contain the mineralized solution and the coal gangue aggregate 4; the container is made of corrosion-resistant material, which is suitable for the reaction environment of the microbial mineralization process. The container body 1 is provided with a diversion area and a reaction area, which are separated by a longitudinal grid 101. In this embodiment, the longitudinal grid 101 is located at 1 / 3 of the length of the container body; the diversion area and the reaction area are connected through the gap of the longitudinal grid 101 to ensure that the mineralized solution can flow freely during the circulation process. In this embodiment, the total length of the container body 1 is 450 units in length, the total width is 150 units in length, and the total height is 200 units in length; the length of the diversion area is 150 units in length, and the length of the reaction area is 300 units in length.

[0103] Gangue aggregate suspension 2: The gangue aggregate suspension 2 is horizontally arranged in the reaction zone of the container body, and is used to place the gangue aggregate 4; the gangue aggregate suspension 2 is made of corrosion-resistant material, and a plurality of through holes are evenly distributed thereon; the gangue aggregate suspension 2 is arranged in the reaction zone, and maintains a spacing of 50 units of length from the bottom of the container body to ensure that the mineralized solution can cover the gangue aggregate 4 from all angles, including the bottom area of ​​the gangue aggregate 4, to avoid the problem of poor contact due to static placement.

[0104] Bacterial liquid power circulation system: The bacterial liquid power circulation system includes a circulation pump 301, a circulation pipeline 302 and a diversion nozzle device 303; the circulation pump 301 is located at the bottom of the diversion area, and the mineralized solution is pumped from the bottom of the container to the top through the circulation pipeline 302, and the solution is evenly distributed around the gangue aggregate 4 in the reaction area through the diversion nozzle device 303; the circulation pipeline 302 connects the diversion area and the reaction area, and is connected to the diversion nozzle device 303 through the top outlet to achieve efficient transportation and uniform distribution of the mineralized solution; the diversion nozzle device 303 is located above the aggregate rack, which ensures that the mineralized solution can continue to flow on the surface and internal pores of the gangue aggregate 4, fully covering the gangue aggregate 4, forming a dynamic circulation flow environment, thereby significantly improving the uniformity and efficiency of mineralization deposition; the entire bacterial liquid power circulation system is completely immersed in the mineralized solution, and through the power drive of the circulation pump, the closed circulation flow of the solution between the diversion area and the reaction area is achieved, avoiding the problem of biofilm accumulation under static conditions.

[0105] The diversion nozzle device 303 adopts a porous diversion design, and its structure consists of a plurality of evenly distributed nozzles to achieve uniform distribution of the mineralizing solution; the aperture and number of the nozzles are optimized according to the particle size and laying area of ​​the gangue aggregate 4 to ensure that the sprayed solution can cover the surface of the gangue aggregate and penetrate into the internal pores; in order to enhance the flow performance, the diversion nozzle device 303 is made of corrosion-resistant and low-friction materials, and the smooth inner wall design reduces the flow resistance of the solution, effectively preventing microbial deposition or particles in the mineralizing solution from clogging the nozzle, thereby ensuring the long-term stable operation of the nozzle.

[0106] Temperature control system: The temperature control system is arranged in the container body, including a temperature sensor and a heating device, and the temperature control system is used to maintain the temperature of the mineralization solution.

[0107] Through the above structural design and the functional realization of the bacterial liquid power circulation system, the device of this embodiment can significantly improve the mineralization efficiency and deposition uniformity of coal gangue aggregate, and is suitable for large-scale coal gangue aggregate modification and treatment scenarios.

[0108] Embodiment 5:

[0109] This embodiment discloses a high-efficiency gangue aggregate modification device based on microbial mineralization technology, referred to as a power bacterial liquid circulation device; the device mainly includes a container body, a gangue aggregate suspension, a bacterial liquid power circulation system, a temperature control system and a reverse flow control device.

[0110] Container body: The container body adopts a rectangular structure to contain mineralized solution and coal gangue aggregate. The container is made of corrosion-resistant material, suitable for the reaction environment of microbial mineralization process. The container is provided with a diversion area and a reaction area, which are separated by a longitudinal grid; the diversion area and the reaction area are connected through the grid gap to ensure that the mineralized solution can flow freely during the circulation process.

[0111] Gangue aggregate suspension: The gangue aggregate suspension is horizontally arranged in the reaction zone of the container body and is used to place the gangue aggregate; the suspension is made of corrosion-resistant material and has multiple through holes evenly distributed on it; the bottom of the suspension is kept at a distance of 1 / 4 of the container height from the bottom of the container body to ensure that the mineralizing solution can cover the gangue aggregate from all angles and avoid the problem of poor contact caused by static placement.

[0112] Bacterial liquid power circulation system: The bacterial liquid power circulation system includes a circulation pipe and a circulation pump. One end of the circulation pipe is connected to the water inlet of the diversion area of ​​the container body, and the other end is connected to the water outlet of the reaction area to form a closed circulation loop; the circulation pump is arranged in the middle of the pipe to drive the continuous circulation of the mineralized solution in the container; by adjusting the flow rate of the circulation pump, the mineralized solution can fully flow on the surface of the coal gangue aggregate and in the internal pores, preventing the formation of biofilm and improving the uniformity and depth of mineralized deposition.

[0113] Temperature control system: The temperature control system includes a temperature sensor and a heating device, which are installed inside the container body; the temperature sensor detects the temperature of the mineralization solution in real time, and the heating device performs heating control according to the feedback of the temperature sensor to ensure that the temperature of the mineralization solution is always maintained within the range of 25-35°C, providing a stable environment for the microbial mineralization process.

[0114] Reverse flow control device: The reverse flow control device is arranged in the bacterial liquid power circulation system, and includes a timing controller and a circulation pump; the timing controller is connected to the circulation pump, and can drive the circulation pump to reverse at a fixed time, automatically changing the flow direction of the mineralized solution every 2-5 hours, thereby realizing periodic forward and reverse flow in the container, and further improving the coverage uniformity of the mineralized solution on the aggregate surface and internal pores.

[0115] Through the synergistic effect of the partition design in the container, the aggregate suspension structure and the power circulation system, the device achieves sufficient coverage and flow of the mineralized solution on the surface and in the pores of the gangue aggregate; the temperature control system provides a suitable mineralization environment, and the reverse flow control device further enhances the uniform distribution of the solution, making the mineralization deposition more uniform and efficient; the device is suitable for large-scale modification of gangue aggregates and has significant environmental protection and economic benefits.

[0116] Embodiment 6:

[0117] This embodiment discloses an efficient gangue aggregate modification device based on microbial mineralization technology. The bacterial liquid power circulation system is further optimized on the basis of Embodiment 4 or Embodiment 5. The bacterial liquid power circulation system adopts a layered circulation design, which significantly enhances the dynamic regulation ability of the mineralized solution. The other parts of this embodiment, including the basic structure and function of the container body, the gangue aggregate suspension, the temperature control system and the reverse flow control device are consistent with those of Embodiment 5, and only the different parts are described below.

[0118] The bacterial liquid dynamic circulation system of this embodiment adopts a layered circulation design, dividing the reaction area into an aggregate surface area, a middle-layer pore area and a bottom-layer flow area, and driving the mineralized solution flow in each layer through independent pipes and circulation pumps; the flow rate is set according to the mineralization demand, the flow rate in the aggregate surface area is 1L per minute, the flow rate in the middle-layer pore area is 0.5L per minute, and the flow rate in the bottom-layer flow area is 2L per minute, ensuring that the mineralized solution can evenly cover the aggregate surface and penetrate into the internal pores; at the same time, using a reverse flow control device, the flow direction of the mineralized solution is switched every 3 hours, further enhancing the solution's coverage ability inside the aggregate and avoiding insufficient local deposition.

[0119] By combining layered circulation and dynamic regulation, this embodiment achieves precise control of the mineralized solution in different circulation areas, significantly optimizes the uniformity and depth of the deposition layer, effectively improves the efficiency and effect of coal gangue aggregate modification, and is suitable for high-demand large-scale processing scenarios.

[0120] The above specific examples are used to illustrate the present application, which is only used to help understand the present application and is not intended to limit the present application. For technicians in the technical field to which the present application belongs, they can also make some simple deductions, deformations or substitutions based on the ideas of the present application.

Claims

1. An efficient coal gangue aggregate modification method based on microbial mineralization technology, characterized in that: include: Select mineralizing microorganism strains: select a mixed strain of Bacillus pasteurianus and Bacillus coli as mineralizing microorganism strains; Forming a microbial mineralization system: fully mixing urea, calcium source and nutrients in pure water to prepare a mineralization solution, inoculating the mineralizing microbial strain into the mineralization solution, adjusting the pH value of the mineralization solution to 8.5-10, and maintaining the temperature of the mineralization solution at 25-35° C. to form a microbial mineralization system suitable for microbial growth; Pretreatment of coal gangue: crush the coal gangue into particles with a particle size of 5-20mm and screen them to obtain coal gangue aggregate with uniform particle size; Dynamic mineralization treatment: immersing the gangue aggregate in the microbial mineralization system, and placing the gangue aggregate on a suspension rack to ensure that the bottom of the gangue aggregate is suspended; maintaining the mineralization solution in a circulating flow state, so that the mineralization solution can fully contact the surface of the aggregate and penetrate into the internal pores, avoiding the accumulation of biofilm on the surface of the gangue aggregate, and hindering the subsequent mineralization solution from penetrating into the aggregate; Maintain the circulating flow state of the mineralizing solution for 5-10 days to form calcium carbonate precipitation on the surface and internal pores of the coal gangue aggregate; Washing and drying: The calcium carbonate-deposited gangue particles are removed from the mineralizing solution, rinsed with pure water, and then dried to constant weight in a drying equipment.

2. The efficient coal gangue aggregate modification method based on microbial mineralization technology according to claim 1 is characterized in that: The nutrient components include tryptone, yeast powder, sodium chloride and glucose; The mass ratio of the nutrients to urea is as follows: Tryptone: 5-15 copies Yeast powder: 2-8 parts Sodium chloride: 2-8 parts Glucose: 0.5-3 parts Urea: 10-30 parts.

3. The efficient coal gangue aggregate modification method based on microbial mineralization technology according to claim 1 is characterized in that: The calcium source includes calcium nitrate, calcium acetate or calcium chloride, and the calcium ion concentration is 0.15-0.25 mol / L.

4. The efficient coal gangue aggregate modification method based on microbial mineralization technology according to claim 1 is characterized in that: The concentration of the mineralized microbial strain is 2.6×10 8 cells / ml-4.3×10 9 cells / ml.

5. The efficient coal gangue aggregate modification method based on microbial mineralization technology according to claim 2 is characterized in that: In parts by mass, the ratio of tryptone: yeast powder: NaCl: glucose: urea is 10: 5：5：1：20。 6. The efficient coal gangue aggregate modification method based on microbial mineralization technology according to claim 1 is characterized in that: The circulation flow direction of the mineralizing solution is reversed every 2-5 hours.

7. An efficient coal gangue aggregate modification device based on microbial mineralization technology, characterized in that: include: Container body: The container body is a rectangular structure used to contain mineralizing solution and coal gangue aggregate; Gangue aggregate suspension: the gangue aggregate suspension is horizontally arranged in the container body, and a plurality of through holes are evenly distributed on the gangue aggregate suspension. The gangue aggregate suspension is used to suspend the gangue aggregate in the air so that the bottom of the gangue aggregate maintains a distance from the bottom of the container; Bacterial liquid power circulation system: including a circulation pipeline and a circulation pump, the bacterial liquid power circulation system is used to drive the mineralization solution to continuously circulate in the container; Temperature control system: The temperature control system is arranged in the container body, including a temperature sensor and a heating device, and the temperature control system is used to maintain the temperature of the mineralization solution.

8. The high-efficiency coal gangue aggregate modification device based on microbial mineralization technology according to claim 7 is characterized in that: Also includes: Reverse flow control device: The reverse flow control device is arranged in the circulation pump, and includes a timing controller. The timing controller drives the circulation pump to reverse within a preset time interval, changes the flow direction of the mineralizing solution, and realizes the periodic forward and reverse flow of the mineralizing solution in the container body.

9. The high-efficiency coal gangue aggregate modification device based on microbial mineralization technology according to claim 7 is characterized in that: The container body is provided with a longitudinal grid, which divides the container body into a guide area and a reaction area, and the gangue aggregate suspension is arranged in the reaction area.

10. The high-efficiency coal gangue aggregate modification device based on microbial mineralization technology according to claim 6, characterized in that: The distance between the gangue aggregate suspension frame and the bottom of the container body is 1 / 4 of the height of the container.

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