Quality control system for high-mica granite machine-made sandstone concrete

Abstract

The invention relates to a high-mica granite machine-made sandstone concrete quality control system. The high-mica granite machine-made sandstone concrete quality control system comprises the following steps that S1, pretreated granite aggregate is conveyed into double-cavity type microwave irradiation equipment; s2, the dielectric constant of the granite aggregate is detected through double-cavity microwave irradiation equipment, high-frequency treatment is conducted on the granite aggregate with the dielectric loss factor larger than 0.05, and low-frequency treatment is conducted on the granite aggregate with the dielectric loss factor smaller than or equal to 0.05; s3, the granite aggregate subjected to microwave treatment is conveyed into liquid nitrogen spraying equipment, microcracks are generated between mica layers through thermal shock stress, and mica interlayer stripping is triggered; and S4, the granite aggregate is recovered to the room temperature through temperature recovery equipment, and the granite aggregate is separated from mica on the granite aggregate through winnowing impurity removal equipment. The microwave-liquid nitrogen synergistic stripping technology is adopted, the content of mica in the high-mica granite is reduced, and control over the quality of the granite machine-made gravel concrete is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete production, in particular to a quality control system for high-mica granite machine-made sandstone concrete. Background Art

[0002] The performance of concrete is highly dependent on the quality of its aggregate. Granite is one of the ideal sources of aggregate due to its high hardness and strong weather resistance. However, the mica content in some granites (such as two-mica granite and biotite granite) is as high as 5%-10%, which leads to the following problems in concrete: Strength loss: The mica cleavage surface is smooth, and the bonding strength with cement slurry is weak, resulting in a 20%-30% reduction in 28-day compressive strength. Durability deterioration: Mica expands after absorbing water, causing microcracks, and the chloride ion diffusion coefficient increases by 1-2 orders of magnitude. Workability fluctuations: Flaky mica hinders particle flow, and the slump loss rate increases by more than 40%. Currently, approximately 300 million tons of natural granite aggregates after tunnel excavation are discarded each year worldwide due to excessive mica content.

[0003] Mica is an aluminosilicate mineral with a continuous layered silicon-oxygen tetrahedral structure. Mica, a harmful impurity in granite sand, significantly affects the workability, mechanical properties, and durability of concrete. The interface is the weakest link in concrete and plays a crucial role in its failure. The failure process is closely related to the properties of the aggregate and the strength differences between the aggregates. Aggregate type, strength, shape, surface impurities, pore structure, water absorption, and surface bond strength all have a significant impact on concrete, particularly high-performance concrete.

[0004] The existing technologies for processing mica in granite mainly include mechanical sorting and acid washing. The mechanical sorting method uses the density difference between mica and quartz / feldspar (mica is 2.7-3.1g / cm 3 , quartz 2.65g / cm 3 ) , using airflow or heavy liquid sorting, but this can easily lead to fine particle loss, with a sorting efficiency of only 50%-60% for particles <0.6mm, resulting in a shortage of fine aggregate. Acid treatment uses hydrofluoric acid (HF) to dissolve the Al3+ between mica layers, which can easily corrode the aggregate surface, increase porosity by over 15%, and increase the crushing value by 3-5 percentage points. After mechanical sorting, the mica residue still reaches 3-4%, and 50-80L of fluoride-containing wastewater is generated per ton of aggregate, resulting in high treatment costs.

[0005] To address the shortcomings of existing technologies, the present invention provides a quality control system for high-mica granite manufactured sand and gravel concrete. This system utilizes microwave-liquid nitrogen synergistic stripping technology to reduce the mica content in high-mica granite, thereby effectively controlling the quality of granite manufactured sand and gravel concrete. This system eliminates the need for acid wash wastewater, allows for recyclable liquid nitrogen (recovery rate >85%), and offers high selectivity, with a mica stripping rate >80% and a quartz / feldspar damage rate <3%. Summary of the Invention

[0006] In view of the above problems, the present invention provides a quality control system for high-mica granite machine-made sand and gravel concrete, which adopts microwave-liquid nitrogen synergistic stripping technology to reduce the mica content in high-mica granite to achieve quality control of granite machine-made sand and gravel concrete.

[0007] The specific technical solutions are as follows:

[0008] A high-mica granite machine-made sandstone concrete quality control system comprises the following steps:

[0009] S1, transporting the pre-treated granite aggregate to a double-cavity microwave irradiation device, utilizing the sensitivity of water molecules between mica layers to microwaves, inducing the expansion of the mica crystal layers through microwave radiation, thereby weakening the interlayer bonding force;

[0010] S2, dual-cavity microwave irradiation equipment is used to test the dielectric constant of granite aggregates. Granite aggregates with a dielectric loss factor greater than 0.05 are subjected to high-frequency treatment, and granite aggregates with a dielectric loss factor less than or equal to 0.05 are subjected to low-frequency treatment;

[0011] S3, transporting the microwave-treated granite aggregate to a liquid nitrogen spraying device, spraying liquid nitrogen on the surface of the granite aggregate, causing micro cracks between mica layers through thermal shock stress, and inducing delamination of the mica layers;

[0012] S4, returning the granite aggregate to room temperature through a temperature return device, and separating the granite aggregate from the mica thereon through an air separation and impurity removal device.

[0013] Furthermore, the method further comprises the following steps:

[0014] S5, soaking the air-selected granite aggregate in a mixture of a silane coupling agent and nano-SiO2 sol, and drying at 120°C to form a composite layer with a thickness of 250-350 nm, thereby reducing the porosity of the mica-cement interface transition zone;

[0015] S6, the granite aggregate is pre-coated with the MgO-KH2PO4 system, and the generated struvite phase seals the mica cleavage surface and then participates in the preparation of concrete.

[0016] Furthermore, in step S1, the pretreatment of the granite aggregate includes the following steps:

[0017] S11, crushing the granite aggregate and separating the crushed granite aggregate into two grades of 5-10 mm and 10-20 mm through a vibrating screen;

[0018] S12, the granite aggregate is transported to the vibrating feeder in a graded manner, and the vibrating feeder evenly transports the granite aggregate to the pulse airflow cleaning device to remove dust on the surface of the granite aggregate.

[0019] Furthermore, in step S2, the dielectric constant detection of the granite aggregate includes the following steps:

[0020] S21, intermittently detecting the granite aggregates transported to the double-cavity microwave irradiation equipment through a plurality of dielectric constant sensors;

[0021] S22, obtaining dielectric loss factors detected by a plurality of dielectric constant sensors each time, and calculating an average value of the plurality of dielectric loss factors as an ideal value for this detection;

[0022] S23, performing corresponding high-frequency processing or low-frequency processing on the granite aggregate tested this time according to the ideal value of this time.

[0023] Furthermore, in step S2, the high frequency treatment is performed at a frequency of 2450 MHz, a power density of 3.5 kW / t, and lasts for 50-60 seconds.

[0024] Furthermore, in step S2, the low-frequency treatment has a frequency of 915 MHz and a power density of 1.8 kW / t, and lasts for 80-90 seconds.

[0025] Furthermore, in step S3, spraying liquid nitrogen includes the following steps:

[0026] S31, the microwave-treated granite aggregate is alternately temporarily stored in a dual-station buffer bin. When one buffer bin is in a collecting state, the other is in a feeding state to the liquid nitrogen spraying device. The internal temperature of the buffer bin is tested before each feeding.

[0027] S32, the aggregate after temperature detection flows into the liquid nitrogen spraying equipment, and several nozzles are individually controlled to spray liquid nitrogen onto the granite aggregate;

[0028] S33, opening a corresponding number of nozzles according to the temperature of the buffer bin before feeding. The higher the temperature, the more nozzles are opened.

[0029] Furthermore, in step S5, the forming of the composite layer includes the following steps:

[0030] S51, ethyl orthosilicate, ethanol, and water were mixed in a molar ratio of 1:8:2, and 3-3.5 wt% of a silane coupling agent was added. The pH was adjusted to 9.0-9.8 with ammonia catalyst, and hydrolyzed for 4 h.

[0031] S52, soaking the air-selected granite aggregate for 30 minutes, centrifugally dehydrating for 30 seconds, and then thermally curing at 120°C for 1 hour;

[0032] S53, the film thickness is measured by ellipsometer and controlled at 300±50nm.

[0033] Furthermore, in step S6, the pre-wrapping includes the following steps:

[0034] S61, setting the molar ratio of MgO and KH2PO4 to 3:1, the water-cement ratio to 0.10, and the amount of borax retarder added to 1.5%, and performing the first coating of the granite aggregate using a twin-shaft forced mixer;

[0035] S62, setting the molar ratio of MgO and KH2PO4 to 5:1, the water-cement ratio to 0.15, and the addition amount of borax retarder to 2.5%, and performing a second coating on the granite aggregate using a twin-shaft forced mixer.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The present invention provides a quality control system for high-mica granite machine-made sand and gravel concrete. The system utilizes the sensitivity of water molecules between mica layers to microwaves, induces the expansion of mica crystal layers through microwave radiation, weakens the interlayer bonding force, and then sprays liquid nitrogen onto the surface of the granite aggregate. The thermal shock stress causes microcracks between the mica layers, triggering the delamination of the mica layers. The microwave-liquid nitrogen synergistic delamination technology is used to reduce the mica content in the high-mica granite, thereby achieving quality control of the granite machine-made sand and gravel concrete.

[0038] (2) The present invention provides a high-mica granite machine-made sand and gravel concrete quality control system, which detects the dielectric constant of the high-mica granite aggregate before microwave irradiation, performs high-frequency treatment on the granite aggregate with a dielectric loss factor greater than 0.05, and performs low-frequency treatment on the granite aggregate with a dielectric loss factor less than or equal to 0.05, thereby using different irradiation methods to irradiate the mica on the granite aggregate, thereby facilitating the stripping of the mica.

[0039] (3) The present invention provides a high-mica granite machine-made sand and gravel concrete quality control system, which further enhances the bonding strength with cement by immersing the granite aggregate after microwave-liquid nitrogen synergistic stripping in a mixture of silane coupling agent and nano-SiO2 sol, and pre-coating the granite aggregate with a MgO-KH2PO4 system.

[0040] (4) The present invention provides a high-mica granite machine-made sand and gravel concrete quality control system, which is equipped with a dual-cavity microwave irradiation device. The dielectric constant detection component is used to detect the dielectric loss factor of the aggregate in each detection area, and the aggregate is distributed to the corresponding high-frequency irradiation cavity or low-frequency irradiation cavity through the material distribution component, so as to facilitate the classification and treatment of different aggregates and improve the mica stripping effect.

[0041] (5) The present invention provides a high-mica granite machine-made sand and gravel concrete quality control system. By setting an alternating caching component, a driving component can make the first station cache bin and the second station cache bin alternately move to a position directly below the second discharge port, which is used for alternately caching the granite aggregate heated from the microwave box. The upper ports of the first station cache bin and the second station cache bin are flush with the upper end surface of the alternating plate, and the upper end surface of the alternating plate is in contact with the lower port of the second discharge port. This arrangement can prevent the microwaves in the microwave box from overflowing from the second discharge port, and is convenient for temperature detection of the aggregate after microwave heating, and is convenient for subsequent regulation of the liquid nitrogen spraying amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of the method of the present invention.

[0043] Figure 2 It is a schematic diagram of the overall equipment location distribution of the present invention.

[0044] Figure 3 It is a structural schematic diagram of the dual-cavity microwave irradiation equipment of the present invention.

[0045] Figure 4 This invention Figure 3 A local enlarged schematic diagram of point A.

[0046] Figure 5 It is a schematic diagram of the structure of the alternating cache component of the present invention.

[0047] Figure 6 It is a schematic diagram of the driving component structure of the present invention.

[0048] Figure 7 It is a structural schematic diagram of the liquid nitrogen spraying equipment of the present invention.

[0049] Figure 8 It is a schematic structural diagram of the temperature recovery equipment of the present invention.

[0050] In the figure: 1. Vibrating feeder; 2. Pulse airflow cleaning equipment; 3. Dual-cavity microwave irradiation equipment; 31. Microwave box; 32. Dielectric constant detection component; 321. Dielectric constant detection box; 322. Second feed port; 323. Third discharge port; 324. Third conveyor belt; 325. Dielectric constant sensor; 33. Partition; 34. High-frequency irradiation cavity; 35. Low-frequency irradiation cavity; 36. Feed pipe; 37. Distributor assembly; 371. Distributor plate; 372. Distributor shaft; 38. First feed port; 39. First discharge port; 310. Second discharge port; 311. First magnetron; 312. Second magnetron; 313. First conveyor belt; 314. Second conveyor belt; 4. Alternating buffer component; 41. Rectangular Frame; 42. Alternating plate; 43. First station cache bin; 44. Second station cache bin; 45. First groove; 46. First guide support rod; 47. First telescopic cylinder; 48. Second telescopic cylinder; 49. Temperature sensor; 410. Hinge block; 5. Liquid nitrogen spraying equipment; 51. Spray box; 52. Spray chamber; 53. Fourth conveyor belt; 54. Third feed port; 55. Fourth feed port; 56. Spray main pipe; 57. Nozzle; 58. Recovery pipe; 59. Fourth discharge port; 6. Temperature return equipment; 61. Temperature return box; 62. Fifth feed port; 63. Fifth conveyor belt; 64. Sixth conveyor belt; 65. Hot air box; 66. Heating rod; 67. Supply fan; 68. Fifth discharge port; 7. Air separation and impurity removal equipment. DETAILED DESCRIPTION

[0051] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0052] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0053] Example 1

[0054] The present invention provides a high mica granite machine-made sandstone concrete quality control system, referring to Figure 1 , including step S1, transporting the pre-treated granite aggregate to the double-cavity microwave irradiation equipment 3, utilizing the sensitivity of water molecules between mica layers to microwaves (dielectric loss tanδ = 0.03-0.05), inducing the expansion of the mica crystal layer through microwave radiation, thereby weakening the interlayer bonding force. Mica (KAl2(AlSi3O 10The interlayer hydroxyl groups (-OH) and adsorbed water in the mica (OH)2) exhibit high dielectric loss (tan δ ≈ 0.04) to microwaves (2450 MHz), while quartz and feldspar barely absorb microwaves. This targeted heating of the water between the mica interlayers can locally raise the temperature to 110-150°C, while the granite matrix temperature is <80°C. Microwave heating causes the mica interlayers to expand, while liquid nitrogen (-196°C) spraying causes them to shrink instantaneously, generating shear stress.

[0055] The pretreatment of the granite aggregate comprises the following steps:

[0056] S11, crushing the granite aggregate and separating the crushed granite aggregate into two grades of 5-10 mm and 10-20 mm using a vibrating screen (removing fine powder and drying with hot air at 80°C to a moisture content of less than 0.5% to prevent free water from interfering with microwave heating);

[0057] S12, the granite aggregate is transported to the vibrating feeder 1 in a graded manner. The vibrating feeder 1 evenly transports the granite aggregate to the pulse airflow cleaning device 2 to remove dust from the surface of the granite aggregate. Pulse airflow cleaning (pressure 0.6MPa, gas consumption 3m 3 / t), remove surface powder (<0.075mm particles).

[0058] In step S2, the dual-cavity microwave irradiation equipment 3 detects the dielectric constant of the granite aggregate, performs high-frequency treatment on the granite aggregate with a dielectric loss factor greater than 0.05, and performs low-frequency treatment on the granite aggregate with a dielectric loss factor less than or equal to 0.05.

[0059] In step S2, the dielectric constant detection of the granite aggregate includes the following steps:

[0060] S21, intermittently detecting the granite aggregate delivered to the dual-cavity microwave irradiation device 3 through a plurality of dielectric constant sensors 325;

[0061] S22, obtaining the dielectric loss factors detected by the plurality of dielectric constant sensors 325 each time, and calculating an average value of the plurality of dielectric loss factors as an ideal value for this detection;

[0062] S23, performing corresponding high-frequency processing or low-frequency processing on the granite aggregate tested this time according to the ideal value of this time.

[0063] Several dielectric constant sensors 325 for testing are arranged sequentially along the conveying direction of the granite aggregate. The dielectric constant sensors 325 operate synchronously and perform intermittent testing. The area between the two dielectric constant sensors 325 that are farthest apart is the testing area, and the time it takes for the granite aggregate to pass through this testing area is the intermittent wake-up time of the dielectric constant sensors 325. In other words, the dielectric constant sensors 325 perform centralized testing on several aggregates passing through the testing area. After the tested aggregates flow into the dual-cavity microwave irradiation device 3, the aggregates to be tested subsequently flow through the testing area via the third conveyor belt 324 for testing, and this cycle continues.

[0064] The high-frequency treatment frequency is 2450MHz, the power density is 3.5kW / t, and the duration is 50-60 seconds. The surface temperature of the granite aggregate is raised to 110±5℃ (infrared temperature feedback control). The water molecules between the mica layers (structural formula KAl2(AlSi3O 10 )(OH)2) dielectric heating causes the interlayer spacing to expand from 1.0 nm to 1.8 nm (XRD detection).

[0065] The low-frequency treatment has a frequency of 915MHz, a power density of 1.8kW / t, and lasts for 80-90 seconds. It heats the granite aggregate to 80-90°C in the deep layer and increases the penetration depth by three times.

[0066] The transmission system adopts high temperature resistant alumina ceramic conveyor belt, which can continuously transport aggregates, with a temperature resistance of -200 to 300℃ and an adjustable speed of 0.2-2m / min.

[0067] In step S3, the microwave-treated granite aggregate is transported to a liquid nitrogen spraying device 5, where liquid nitrogen is sprayed onto the surface of the granite aggregate. This thermal shock stress causes microcracks between the mica layers, triggering delamination. The liquid nitrogen is stored in a Dewar tank (5000L capacity, 1.2MPa operating pressure). The granite aggregate is cooled from 110°C to -196°C, creating microcracks (5-20μm wide) between the mica flakes, achieving a delamination efficiency of 82-87%. After the spraying, the liquid nitrogen becomes gaseous, and a condensation recovery tower collects volatile organic compounds. The residual gas is treated by catalytic oxidation.

[0068] Spraying liquid nitrogen includes the following steps:

[0069] S31, the microwave-treated granite aggregate is alternately temporarily stored in a double-station buffer bin, with one buffer bin in a collecting state while the other is feeding the liquid nitrogen spraying device 5. The internal temperature of the buffer bin is tested before each feeding.

[0070] S32, the aggregate after temperature detection flows into the liquid nitrogen spraying equipment 5, and a plurality of nozzles 57 are individually controlled to spray liquid nitrogen onto the granite aggregate;

[0071] S33, opening a corresponding number of nozzles 57 according to the temperature of the buffer bin before feeding. The higher the temperature, the more nozzles 57 are opened.

[0072] Several spraying nozzles 57 in the liquid nitrogen spraying device 5 are arranged in sequence along the conveying direction of the granite aggregate, and each nozzle 57 is controlled individually; the nozzles 57 spray liquid nitrogen (-196°C) with a flow rate of ≥2L / min·t for 20 seconds. The thermal shock stress causes micro cracks >5μm between the mica layers.

[0073] S33, according to the temperature of the buffer bin before feeding, corresponding number of nozzles 57 are opened. The higher the temperature, the more nozzles 57 are opened. The nozzles 57 are fan-shaped vacuum insulation nozzles with a spray angle of 60 degrees and a spray distance of 150 mm.

[0074] Step S4: The granite aggregate is returned to room temperature by the temperature return device 6, and the granite aggregate is separated from the mica by the air separation and impurity removal device 7. The granite aggregate is returned to room temperature (25°C) by 40°C hot air to avoid condensation water adsorption, and the mica flakes (2.7-3.1g / cm 3 ) and granite particles (2.6-2.8g / cm 3 ) density difference, multi-stage air flow sorting (wind speed 8-12m / s, inclination angle 25°) is used to separate the flat particles (mica-enriched part) in 5-20mm aggregate, which can reduce the mica content to less than 2%.

[0075] Example 2

[0076] There are three major defects in the interface transition zone between high-mica granite aggregate and cement matrix: physical defects: smooth cleavage surface of mica (contact angle>100°), weak mechanical bite force; chemical inertness: mica (KAl2(AlSi3O 10 )(OH)2) The surface hydroxyl density is low (only 1.2-1.5 / nm 2 ), it is difficult to bond with cement hydration products; pore concentration: the porosity of the interface transition zone is 3-5 times higher than that of the cement matrix.

[0077] The present invention provides a quality control system for high-mica granite machine-made sandstone concrete. Based on Example 1, the system further includes step S5, wherein the air-selected granite aggregate is immersed in a mixture of a silane coupling agent and a nano-SiO2 sol (particle size 20 nm, solid content 15%), followed by drying at 120°C to form a composite layer 250-350 nm thick. This reduces the porosity of the mica-cement interface transition zone by more than 40%. The nano-SiO2 network penetrates between the mica layers (to a depth of 2-5 μm), providing physical anchoring points. The nano-SiO2 sol is recovered using an ethanol recovery system.

[0078] The formation of the composite layer comprises the following steps:

[0079] S51, ethyl orthosilicate, ethanol, and water were mixed in a molar ratio of 1:8:2, and 3-3.5 wt% of a silane coupling agent was added. The pH was adjusted to 9.0-9.8 with ammonia catalyst, and hydrolyzed for 4 h.

[0080] S52, soaking the air-selected granite aggregate for 30 minutes, centrifugally dehydrating (speed 800 rpm, 30 seconds), and then thermally curing at 120°C for 1 hour;

[0081] S53, the film thickness is measured by ellipsometer and controlled at 300±50nm.

[0082] Film formation mechanism: hydrolysis condensation reaction to form ≡Si-O-Si≡ network, infrared spectrum detection 1080cm -1 The intensity of the characteristic peak at the pore size is increased by 2.3 times.

[0083] In step S52, the aggregate soaking step includes: preheating the aggregate to 60±5°C (to reduce surface tension); immersing the aggregate in the sol (liquid-solid ratio 3:1), and ultrasonically treating for 15 minutes; centrifugal dehydration (800 rpm, 30 seconds, residual liquid rate <5%); and thermal curing at 120°C for 1 hour to form a porous SiO2 gel film.

[0084] The method further includes step S6, wherein the granite aggregate is pre-coated with a MgO-KH2PO4 system, and the struvite phase formed seals the mica cleavage plane, and then participates in the preparation of concrete. The coating thickness is 150±20 μm (controlled by an eddy current thickness gauge).

[0085] The pre-wrapping comprises the following steps:

[0086] In step S61, a MgO / KH2PO4 molar ratio of 3:1, a water-cement ratio of 0.10, a borax retarder addition amount of 1.5%, and an optional pore former (polystyrene microspheres, particle size 20-50 μm) were set. The granite aggregate was coated with a first layer using a biaxial forced mixer. During curing, steam curing at 80°C for 2 h was used to form a transition layer with a porosity of 35 ± 3%.

[0087] S62, with a MgO / KH2PO4 molar ratio of 5:1, a water-cement ratio of 0.15, and a borax retarder addition of 2.5%, and an optional 1% nano-Al2O3 (to enhance wear resistance), is coated with a second layer of granite aggregate using a twin-shaft forced mixer. After pore filling, the surface hardness reaches HV450. After 24 hours of room temperature curing, the surface hardness reaches HV450 (determined by microindentation).

[0088] Example 3

[0089] Based on Example 1, the dual-cavity microwave irradiation equipment 3 includes a microwave box 31, and the upper end of the microwave box 31 is provided with a dielectric constant detection component 32 for conveying and detecting granite aggregate. The interior of the microwave box 31 is divided into a high-frequency irradiation cavity 34 and a low-frequency irradiation cavity 35 by a partition 33. A feeding pipe 36 is also vertically provided at one end of the interior of the microwave box 31, and a material distribution component 37 for distributing granite aggregate to the high-frequency irradiation cavity 34 or the low-frequency irradiation cavity 35 is also provided at the lower port position of the feeding pipe 36.

[0090] The partition 33 is horizontally arranged inside the microwave box 31, and a high-frequency irradiation cavity 34 is formed between the upper end of the partition 33 and the inner wall of the microwave box 31, and a low-frequency irradiation cavity 35 is formed between the lower end of the partition 33 and the inner wall of the microwave box 31. The left end of the partition 33 is provided with a first feed port 38 that passes through the upper and lower parts, and the right end of the partition 33 is provided with a first discharge port 39 that passes through the upper and lower parts. A second discharge port 310 is provided at the right end of the lower end surface of the microwave box 31, a plurality of first magnetrons 311 are provided at the top of the high-frequency irradiation cavity 34, a first conveyor belt 313 is provided at the bottom of the high-frequency irradiation cavity 34, a plurality of second magnetrons 312 are provided at the top of the low-frequency irradiation cavity 35, and a second conveyor belt 314 is provided at the bottom of the low-frequency irradiation cavity 35. The first magnetron 311 generates microwaves with a frequency of 2450 MHz and a power density of 3.5 kW / t. The first conveyor belt 313 operates to move granite aggregate with a dielectric loss factor greater than 0.05 from the high-frequency irradiation chamber 34 and heats the granite aggregate for 50-60 seconds, raising the surface temperature of the granite aggregate to 110±5°C before the aggregate is discharged from the first discharge port 39 and the second discharge port 310. The second magnetron 312 generates microwaves with a frequency of 915 MHz and a power density of 1.8 kW / t. The second conveyor belt 314 operates to move granite aggregate with a dielectric loss factor less than or equal to 0.05 from the low-frequency irradiation chamber and heat the granite aggregate for 80-90 seconds, heating the granite aggregate to a depth of 80-90°C before the aggregate is discharged from the second discharge port 310.

[0091] The dielectric constant detection component 32 includes a dielectric constant detection box 321 arranged at the upper end of the microwave box 31, and a second feed port 322 for communicating with the discharge end of the pulse dust removal equipment 2 is provided at the right end of the upper end surface of the dielectric constant detection box 321, and a third discharge port 323 for communicating with the upper end of the feed pipe 36 is provided at the left end of the lower end surface of the dielectric constant detection box 321. A third conveyor belt 324 for conveying granite aggregate is provided in the left and right directions at the lower interior of the dielectric constant detection box 321, and a plurality of dielectric constant sensors 325 are provided in the left and right directions at the upper end of the interior of the dielectric constant detection box 321.

[0092] The material distribution component 37 includes a material distribution shaft 372, the front and rear ends of the material distribution shaft 372 are respectively connected to the front and rear sides of the microwave box 31 through bearings, and a material distribution plate 371 that swings left and right is provided on the material distribution shaft 372 at the port position of the feed pipe 36, and a servo motor for driving the material distribution shaft 372 is provided on the rear end face of the microwave box 31. When the dielectric constant sensor 325 detects that the dielectric loss factor of the granite aggregate is greater than 0.05, the servo motor controls the dividing plate 371 to swing to the left, and makes the upper end of the dividing plate 371 contact the left inner wall of the feed pipe 36, so that the granite aggregate in the feed pipe 36 flows to the high-frequency irradiation chamber 34; when the dielectric constant sensor 325 detects that the dielectric loss factor of the granite aggregate is less than or equal to 0.05, the servo motor controls the dividing plate 371 to swing to the right, and makes the upper end of the dividing plate 371 contact the right inner wall of the feed pipe 36, so that the granite aggregate in the feed pipe 36 flows to the low-frequency irradiation chamber 35.

[0093] The alternating buffering component 4 includes a rectangular frame 41 disposed on the lower end surface of the microwave box 31. An alternating plate 42 is disposed within the rectangular frame 41. A first workstation buffer compartment 43 and a second workstation buffer compartment 44 are symmetrically disposed on the left and right ends of the alternating plate 42. Temperature sensors 49 are disposed on the inner walls of the first workstation buffer compartment 43 and the second workstation buffer compartment 44, respectively. First grooves 45 are disposed on the front and rear inner walls of the rectangular frame 41, respectively. A driving member for moving the alternating plate 42 left and right is disposed within the first grooves 45. The first workstation buffer compartment 43 and the second workstation buffer compartment 44 are alternately moved to a position directly below the second discharge port 310 to alternately buffer the granite aggregate heated from the microwave box 31. Discharge valves are disposed at the lower ports of the first workstation buffer compartment 43 and the second workstation buffer compartment 44, respectively. The upper ports of the first station cache bin 43 and the second station cache bin 44 are flush with the upper end surface of the alternating plate 42 , and the upper end surface of the alternating plate 42 is in contact with the lower port of the second discharge port 310 . This arrangement can prevent the microwaves in the microwave box 31 from overflowing from the second discharge port 310 .

[0094] The driving member includes a first guide support rod 46 arranged in the left-right direction. The front and rear end surfaces of the alternating plate 42 are respectively provided with a plurality of guide blocks adapted to the first guide support rod 46. The middle positions of the front and rear end surfaces of the alternating plate 42 are respectively provided with hinge blocks 410. The left and right ends of the hinge blocks 410 are respectively provided with a first telescopic cylinder 47 and a second telescopic cylinder 48. The other end of the first telescopic cylinder 47 is hinged to the left inner wall of the first groove 45, and the other end of the second telescopic cylinder 48 is hinged to the right inner wall of the first groove 45. By extending the first telescopic cylinder 47 and retracting the second telescopic cylinder 48, the alternating plate 42 can be moved to the right, so that the first workstation buffer bin 43 moves to a position directly below the second discharge port 310. By retracting the first telescopic cylinder 47 and extending the second telescopic cylinder 48, the alternating plate 42 can be moved to the left, so that the second workstation buffer bin 44 moves to a position directly below the second discharge port 310.

[0095] The liquid nitrogen spraying equipment 5 includes a spray box 51, with a spray chamber 52 disposed at the right end thereof. A spray assembly is disposed within the spray chamber 52. A fourth conveyor belt 53 is disposed in the left-right direction within the spray box 51. A third feed port 54 for receiving granite aggregate from the first-station buffer bin 43 and a fourth feed port 55 for receiving granite aggregate from the second-station buffer bin 44 are disposed at the left end of the upper end surface of the spray box 51. A fourth discharge port 59 is disposed at the right end of the lower end surface of the spray box 51. When the first-station buffer bin 43 is receiving aggregate, the second-station buffer bin 44 performs an internal temperature detection and then delivers aggregate into the spray box 51 through the fourth feed port 55. When the second-station buffer bin 44 is receiving aggregate, the first-station buffer bin 43 performs an internal temperature detection and then delivers aggregate into the spray box 51 through the third feed port 54.

[0096] The spray assembly includes a spray main pipe 56, which extends in a left-right direction. Several nozzles 57 are positioned along the lower end of the main pipe 56, located above the fourth conveyor belt 53. A recovery pipe 58 for recovering exhaust gas is located at the top of the spray chamber 52. The nozzles 57 are fan-shaped, and their spray range covers the width of the fourth conveyor belt 53. Each nozzle 57 is equipped with a solenoid valve. A corresponding number of nozzles 57 are activated based on the temperature of the aggregate being transported by the first or second station buffer bins 43, 44, to cool aggregates of varying temperatures and bring the cooled aggregates to the same temperature.

[0097] The reheating device 6 includes a reheating box 61. The right end of the upper end surface of the reheating box 61 is provided with a fifth feed port 62 connected to the fourth discharge port 59. A fifth conveyor belt 63 and a sixth conveyor belt 64 for conveying aggregate are inclined inside the reheating box 61. The left end of the reheating box 61 is connected to a hot air box 65. The hot air box 65 is provided with a heating rod 66 and a blower fan 67 for conveying hot air into the reheating box 61. The lower end surface of the reheating box 61 is provided with a fifth discharge port 68 for conveying aggregate to the air separation and impurity removal device 7. After spray cooling, the granite aggregate falls into the fifth conveyor belt 63 through the fifth feed port 62, is transported by the fifth conveyor belt 63, and then falls into the sixth conveyor belt 64. After being transported by the sixth conveyor belt 64, it flows to the air separation and impurity removal device 7 through the fifth discharge port 68. The provision of the fifth conveyor belt 63 and the sixth conveyor belt 64 can slow down the discharge time of the aggregate, so that the aggregate can have sufficient time to return to temperature inside the return temperature box 61 .

[0098] The various technical features of the above-described embodiments can be arbitrarily combined. To make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] The above-described embodiments merely illustrate the implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A high mica granite machine-made sandstone concrete quality control system, characterized in that: The following steps are involved: S1, transporting the pre-treated granite aggregate to a double-cavity microwave irradiation device, utilizing the sensitivity of water molecules between mica layers to microwaves, inducing the expansion of the mica crystal layers through microwave radiation, thereby weakening the interlayer bonding force; S2, dual-cavity microwave irradiation equipment is used to test the dielectric constant of granite aggregates. Granite aggregates with a dielectric loss factor greater than 0.05 are subjected to high-frequency treatment, and granite aggregates with a dielectric loss factor less than or equal to 0.05 are subjected to low-frequency treatment; S3, transporting the microwave-treated granite aggregate to a liquid nitrogen spraying device, spraying liquid nitrogen on the surface of the granite aggregate, causing micro cracks between mica layers through thermal shock stress, and inducing delamination of the mica layers; S4, returning the granite aggregate to room temperature through a temperature return device, and separating the granite aggregate from the mica thereon through an air separation and impurity removal device.

2. The high mica granite machine-made sandstone concrete quality control system according to claim 1, characterized in that: The following steps are also included: S5, soaking the air-selected granite aggregate in a mixture of a silane coupling agent and nano-SiO2 sol, and drying at 120°C to form a composite layer with a thickness of 250-350 nm, thereby reducing the porosity of the mica-cement interface transition zone; S6, the granite aggregate is pre-coated with the MgO-KH2PO4 system, and the generated struvite phase seals the mica cleavage surface and then participates in the preparation of concrete.

3. The high mica granite machine-made sandstone concrete quality control system according to claim 1, characterized in that: In step S1, the pretreatment of the granite aggregate includes the following steps: S11, crushing the granite aggregate and separating the crushed granite aggregate into two grades of 5-10 mm and 10-20 mm through a vibrating screen; S12, the granite aggregate is transported to the vibrating feeder in a graded manner, and the vibrating feeder evenly transports the granite aggregate to the pulse airflow cleaning device to remove dust on the surface of the granite aggregate.

4. The high mica granite machine-made sandstone concrete quality control system according to claim 1, characterized in that: In step S2, the dielectric constant detection of the granite aggregate includes the following steps: S21, intermittently detecting the granite aggregates transported to the double-cavity microwave irradiation equipment through a plurality of dielectric constant sensors; S22, obtaining dielectric loss factors detected by a plurality of dielectric constant sensors each time, and calculating an average value of the plurality of dielectric loss factors as an ideal value for this detection; S23, performing corresponding high-frequency processing or low-frequency processing on the granite aggregate tested this time according to the ideal value of this time.

5. The high mica granite machine-made sandstone concrete quality control system according to claim 4, characterized in that: In step S2 , the high frequency treatment is performed at a frequency of 2450 MHz and a power density of 3.5 kW / t for 50-60 seconds.

6. The high mica granite machine-made sandstone concrete quality control system according to claim 5, characterized in that: In step S2 , the low-frequency treatment has a frequency of 915 MHz and a power density of 1.8 kW / t, and lasts for 80-90 seconds.

7. The high mica granite machine-made sandstone concrete quality control system according to claim 1, characterized in that: In step S3, spraying liquid nitrogen includes the following steps: S31, the microwave-treated granite aggregate is alternately temporarily stored in a dual-station buffer bin. When one buffer bin is in a collecting state, the other is in a feeding state to the liquid nitrogen spraying device. The internal temperature of the buffer bin is tested before each feeding. S32, the aggregate after temperature detection flows into the liquid nitrogen spraying equipment, and several nozzles are individually controlled to spray liquid nitrogen onto the granite aggregate; S33, opening a corresponding number of nozzles according to the temperature of the buffer bin before feeding. The higher the temperature, the more nozzles are opened.

8. The high mica granite machine-made sandstone concrete quality control system according to claim 2, characterized in that: In step S5, the formation of the composite layer includes the following steps: S51, ethyl orthosilicate, ethanol, and water were mixed in a molar ratio of 1:8:2, and 3-3.5 wt% of a silane coupling agent was added. The pH was adjusted to 9.0-9.8 with ammonia catalyst, and hydrolyzed for 4 h. S52, soaking the air-selected granite aggregate for 30 minutes, centrifugally dehydrating for 30 seconds, and then thermally curing at 120°C for 1 hour; S53, the film thickness is measured by ellipsometer and controlled at 300±50nm.

9. The high mica granite machine-made sandstone concrete quality control system according to claim 2, characterized in that: In step S6, the pre-wrapping includes the following steps: S61, setting the molar ratio of MgO and KH2PO4 to 3:1, the water-cement ratio to 0.10, and the amount of borax retarder added to 1.5%, and performing the first coating of the granite aggregate using a twin-shaft forced mixer; S62, setting the molar ratio of MgO and KH2PO4 to 5:1, the water-cement ratio to 0.15, and the addition amount of borax retarder to 2.5%, and performing a second coating on the granite aggregate using a twin-shaft forced mixer.

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