Fluidized solidified soil prepared from construction waste, preparation equipment and preparation method

Abstract

The invention relates to the field of flow-state solidified soil, and discloses flow-state solidified soil prepared from construction waste, preparation equipment and a preparation method. The pre-dehydration module is used for controlling the water content of discharged materials to be less than or equal to 14%; the system further comprises a main drying system, an auxiliary material adding device, a water adding device and mixing equipment. The main drying system comprises a high-temperature drying area, a high-temperature buffering area and a heat preservation discharging area which are arranged in the vertical direction, materials treated by the pre-dehydration module are lifted into the high-temperature drying area through lifting equipment, the main drying system comprises at least two sets of material conveying belts, and a plurality of hot air openings are evenly formed in the top of the high-temperature drying area; an inlet of the hot air pipe is communicated with an air cavity heated by a heat source; a recovery channel communicating with the portion, close to the bottom, of the heat preservation discharging area is arranged on one side of the main drying system, and an obliquely-arranged dust baffle is arranged in the recovery channel. According to the invention, the problems of fluctuation of construction waste sources and large change of material moisture content in the prior art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fluidized solidified soil, and in particular to a fluidized solidified soil prepared from construction waste, and a preparation device and method. BACKGROUND

[0002] Construction waste is mainly derived from the process of house demolition, road expansion and municipal engineering construction, and usually contains various components such as concrete blocks, mortar, bricks, stone, metal, wood plastic and a small amount of soil. It has the characteristics of dispersed source, complex components, large particle size span and significant water content fluctuation. If directly stored or transported for landfill, it not only occupies land resources, but also easily causes environmental problems such as dust, leachate and transportation disturbance. Promoting the resource utilization of construction waste and converting it into backfill materials that can be used in engineering has become a long-term and stable technical demand in the industry.

[0003] Fluidized solidified soil is a kind of backfill material formed by mixing fine particle solid materials with cementing materials, mixing water and the like in a certain proportion, which is flowable, self-compacting and pumpable, and is widely used in scenarios such as trench backfill, foundation pit backfill, cavity filling and ground treatment. This kind of material is sensitive to the particle size gradation, water content, water absorption characteristics and impurity content of the raw material: high water content can easily lead to bleeding, segregation, increased settlement and strength dispersion; low water content can cause insufficient flowability, increased pumping resistance, and affect the filling density and construction efficiency. Therefore, when using construction waste to prepare fluidized solidified soil, the fine material composition and water content of the raw material must be stabilized to meet the window requirements of construction performance and strength indicators.

[0004] In the prior art, the preparation of backfill materials from construction waste usually includes pretreatment steps such as crushing, picking and screening to remove metal, wood plastic and other impurities and obtain a relatively stable fine material component; then the water content is reduced by mechanical dewatering such as natural air drying, stacking and airing, pressure filtration / centrifugation, or by hot air drying, and then mixed with cement, fly ash and other cementing materials and admixtures, and mixing water to prepare solidified materials. However, the fine material of construction waste often contains a high proportion of brick powder, mortar powder and fine particles, with high porosity, strong water absorption and large fluctuation: on the one hand, mechanical dewatering is limited for materials with high fine powder content and strong cementation, and the water content of the output is difficult to stabilize; on the other hand, fine powder is easily carried by the airflow during hot air drying to form dust, causing dust accumulation and blockage or wear of the air duct, heat exchanger and subsequent dust removal unit, resulting in an increase in system resistance, imbalance in air distribution, and thus a decrease in drying efficiency and fluctuation in the water content of the output.

[0005] Furthermore, the exhaust gas from drying processes is typically high in humidity and contains dust. If improperly coupled with waste heat recovery, recirculation air, or dehumidification systems, condensation can easily occur when the temperature drops to near the dew point, leading to pipe corrosion, scaling, blockage, and frequent maintenance. Simultaneously, treating high-humidity, dust-laden exhaust gas often requires complex heat exchange, anti-condensation, and dust removal configurations, increasing equipment size, energy consumption, and operating costs. These issues make it difficult for existing processes to consistently and stably control the output moisture content within a suitable mixing range when the source of construction waste fluctuates or the material moisture content varies significantly. This results in inaccurate measurement of the amount of water added during mixing, ultimately manifesting as unstable fluidity, increased risk of segregation and bleeding, and discrete strength indicators, affecting the reliability of engineering applications.

[0006] Therefore, there is an urgent need for a fluidized solidified soil preparation technology and complete set of equipment that takes into account the characteristics of fine materials in construction waste: on the basis of effective pretreatment and moisture content control, to achieve stable, continuous and controllable operation of the drying process, while taking into account the reliability of dust suppression, moisture removal and waste heat utilization, so as to provide a stable input for subsequent auxiliary material addition and water mixing, and improve the consistency of construction performance and engineering applicability of fluidized solidified soil. Summary of the Invention

[0007] Based on the above description, the present invention provides a fluidized solidified soil prepared from construction waste, as well as preparation equipment and preparation method, to solve the problems of fluctuations in the source of construction waste and large variations in the moisture content of materials in existing processes.

[0008] On the one hand, the technical solution of the present invention to solve the above-mentioned technical problems is as follows: a device for preparing fluidized solidified soil using construction waste, comprising:

[0009] The pre-processing module crushes, sorts, and screens construction waste, retaining only mortar particles, fine concrete aggregates, and brick powder.

[0010] The pre-dehydration module is used to pre-dehydrate the material output from the pretreatment module, so that the output moisture content is controlled at ≤14%.

[0011] It also includes a main drying system, an auxiliary material adding device and a water adding device, and a mixing device; the mixing device is used to mix the materials processed by the main drying system, the auxiliary materials added by the auxiliary material adding device and the mixing water added by the water adding device;

[0012] The main drying system includes a high-temperature drying zone, a high-temperature buffer zone, and a heat-insulated discharge zone arranged vertically. The material processed by the pre-dehydration module is lifted into the high-temperature drying zone by a lifting device. The high-temperature drying zone, the high-temperature buffer zone, and the heat-insulated discharge zone each include at least two sets of material conveyor belts. Multiple hot air vents are evenly arranged on the top of the high-temperature drying zone. The multiple hot air vents are connected by hot air pipes. The inlet of the hot air pipes is connected to the air chamber heated by the heat source.

[0013] A recycling channel is provided on one side of the main drying system and is connected to the bottom of the heat-insulated discharge area. An inclined dust baffle is installed in the recycling channel. The top of the recycling channel is connected to a heat exchange device. Air heated by the heat exchange device is delivered to a waste heat recovery pipe. The waste heat recovery pipe is connected to multiple waste heat ports facing the material conveyor belt.

[0014] This equipment achieves stable, low-consumption, and highly consistent production of fluidized solidified soil from construction waste through an integrated process of "pretreatment—pre-dehydration—zoned drying—waste heat recovery—mixing and molding." Firstly, the pretreatment module retains only mortar particles, concrete fine aggregates, and brick powder, significantly reducing the impact of impurities and particle size fluctuations on subsequent mixing and strength dispersion. The pre-dehydration module controls the output moisture content to ≤14%, providing a controllable boundary for thermal drying and water metering, avoiding problems such as "difficulty in drying wet materials, proportion drift, and slurry bleeding." The main drying system is vertically arranged with high-temperature drying zones / high-temperature buffer zones / insulated discharge zones, and each zone is equipped with at least two sets of material conveyor belts and multiple hot air vents at the top for uniform air delivery. This ensures more balanced heating and residence time of the material, reducing local overheating and clumping, and improving drying efficiency and output stability. The vertical layout also reduces land occupation and facilitates continuous lifting and conveying. The recycling channel extends from near the bottom of the insulated discharge area, and together with the inclined dust baffle and heat exchange equipment, it recovers the heat from the humid exhaust gas and directionally replenishes it to the top of the conveyor belt through the waste heat outlet, realizing the cascade utilization of heat. While ensuring the stability of the discharge temperature and moisture content, it reduces the load of the main heat source, reduces dust escape and energy consumption costs, thereby improving the mixing uniformity, construction performance and batch consistency of the fluidized solidified soil.

[0015] Based on the above technical solution, the present invention can be further improved as follows.

[0016] Furthermore, the dust baffle extends downwards at an angle from the side wall of the recycling channel toward the center, and a set of dust baffles is provided on each side of the inner wall of the recycling channel, with the dust baffles on both sides being staggered.

[0017] Furthermore, it also includes the main controller;

[0018] A microwave humidity sensor is installed on the material conveyor belt to acquire the humidity of the material on the conveyor belt and send it to the main controller.

[0019] Temperature and humidity sensors are installed in the high-temperature drying zone, high-temperature buffer zone, and heat-insulating discharge zone to detect the ambient temperature and humidity within the zone and send the data to the main controller.

[0020] The main controller controls the speed of the material conveyor belt and the opening degree of the valves of the hot air duct and the waste heat recovery duct based on the material's humidity, ambient temperature, and humidity.

[0021] Furthermore, the main controller includes a data acquisition unit, a control calculation unit, and an execution control unit; the data acquisition unit is used to filter, calibrate, and fuse the signals from the microwave humidity sensor and the temperature and humidity sensor; the execution control unit is connected to the frequency converter driver of the material conveyor belt, the electric actuator of the hot air duct valve, and the electric actuator of the waste heat recovery pipe valve, respectively, to realize closed-loop regulation of the material conveyor belt speed and the opening degree of each valve.

[0022] Furthermore, the main controller is configured to employ a cascade control logic of "material moisture content outer loop - regional temperature and humidity inner loop": the target moisture content of the material on the material conveyor belt is set in the outer loop, and the outer loop output is used to correct the speed of the material conveyor belt and the opening of the hot air pipe valve; the regional temperature and regional humidity setpoints of the inner loop are used to coordinate and allocate the hot air supply and waste heat supply to the high-temperature drying zone, the high-temperature buffer zone, and the heat-insulated discharge zone, respectively, so that the high-temperature drying zone prioritizes the evaporation driving force, the high-temperature buffer zone is used to suppress local over-drying and dust, and the heat-insulated discharge zone is used to stabilize the fluctuation of the discharge moisture content.

[0023] Secondly, the technical solution of the present invention to solve the above-mentioned technical problems is as follows: using the above-mentioned equipment, the specific steps are as follows:

[0024] S1. Pre-treatment: The construction waste is crushed, sorted and screened to retain only mortar particles, concrete fine aggregates and brick powder to obtain pre-treated materials.

[0025] S2. Pre-dehydration: The pretreated material is pre-dehydrated to ensure that the moisture content of the pre-dehydrated output is ≤14%;

[0026] S3. Main Drying: The pre-dehydrated material is lifted to the high-temperature drying zone of the main drying system by a lifting device, and the material is dried sequentially through the high-temperature drying zone, the high-temperature buffer zone and the heat-insulated discharge zone set in the vertical direction; at least two sets of material conveyor belts are used to transport the material in the high-temperature drying zone, the high-temperature buffer zone and the heat-insulated discharge zone respectively; hot air is sent into multiple hot air vents evenly arranged at the top of the high-temperature drying zone, and the multiple hot air vents are connected by hot air pipes, and the inlet of the hot air pipes is connected to the air chamber heated by the heat source;

[0027] S4. Waste heat recovery and reuse: Moist and hot air is drawn from near the bottom of the heat-insulated discharge area into the recovery channel, and the moist and hot air is heated by heat exchange equipment to form heated air. The heated air is delivered to the waste heat recovery pipe and sprayed out from multiple waste heat ports connected to the waste heat recovery pipe towards the material conveyor belt to participate in drying and heat preservation.

[0028] S5. Mixing: The dried material, the auxiliary materials added by the auxiliary material adding device, and the mixing water added by the water adding device are sent into the mixing equipment for mixing to obtain fluidized solidified soil.

[0029] S6. Closed-loop control: During steps S3 to S5, the material moisture content is collected from the microwave humidity sensor on the material conveyor belt at a control cycle of 0.5 to 5 seconds. The ambient temperature is obtained from temperature and humidity sensors in the high-temperature drying zone, high-temperature buffer zone, and insulated discharge zone. With relative humidity And execute the cascade closed-loop control algorithm of "material moisture content outer loop - regional temperature and humidity inner loop":

[0030] With target moisture content Construct an outer ring with a moisture content of 3%–8%, based on the moisture content error. Calculate the outer loop control variable and adjust the setpoint of the material conveyor belt speed accordingly. With hot air duct valve opening setting value Make corrections, among which The speed limit is within the range of 0.05 to 2.00 m / s. The limit is between 10% and 100%;

[0031] The temperature and humidity of each zone are controlled in a closed-loop manner using an inner ring system. The high-temperature drying zone is set to a temperature of 110–180℃ and a relative humidity of 5%–25%; the high-temperature buffer zone is set to a temperature of 70–120℃ and a relative humidity of 15%–45%; and the insulated discharge zone is set to a temperature of 40–80℃ and a relative humidity of 25%–60%. The opening degree of the waste heat recovery pipe valves is then coordinated and allocated accordingly. ,make The limit is within the range of 0% to 100%;

[0032] Thus, by implementing closed-loop regulation of the material conveyor belt speed, the hot air duct valve opening, and the waste heat recovery duct valve opening, the discharge moisture content can be stably converged to the target moisture content range.

[0033] Through the above technical solution, this method takes "graded impurity removal and fluctuation reduction - low moisture content furnace feeding - vertical zoned tiered drying - exhaust gas waste heat recovery - closed-loop water control during mixing" as the main line to achieve controllable, energy-saving and consistent production of fluidized solidified soil from construction waste: S1 retains only mortar particles, concrete fine aggregates and brick powder, weakening the disturbance of impurities and particle size dispersion on water demand, strength and fluidity; S2 limits the moisture content of the pre-dehydrated discharge to ≤14%, significantly reducing the main drying load and the risk of clumping, and improving the stability of continuous operation. S3 employs a vertical high-temperature drying zone / buffer zone / insulation zone with segmented temperature and humidity control. At least two sets of conveyor belts ensure uniform material distribution and staggered dwell times, coupled with multiple hot air vents at the top for even air delivery, resulting in more thorough drying without overheating and more stable discharge temperature and moisture content. S4 extracts humid air from near the bottom of the insulation zone, heats it through heat exchange to form heated air, and then directs it out through waste heat vents, achieving cascaded utilization of waste heat and surface insulation, reducing fresh air heat consumption and minimizing humid heat exhaust. S5 mixes dry material, auxiliary materials, and metered water to obtain solidified soil with stable flow and strength. S6 collects material moisture content and temperature and humidity in each zone at 0.5–5s intervals, using a cascade control system of "moisture content outer loop—temperature and humidity inner loop," linking and adjusting belt speed, hot air valves, and waste heat valves. Under limited constraints, this rapidly reduces the discharge moisture content to 3%–8%, minimizing batch fluctuations and rework rates, and improving construction adaptability and energy economy.

[0034] Furthermore, in step S4, the humid and hot air in the recovery channel is deflected at least twice by the inclined guide and dust-blocking structures arranged alternately on both sides of the recovery channel, resulting in sedimentation and separation, so as to prevent dust from being carried back into the heat exchange equipment.

[0035] Furthermore, the filtering, calibration, and fusion of sensor signals in step S6 includes at least one of the following: applying first-order low-pass or moving average filtering to the moisture content, temperature, and humidity signals with a filtering window of 5 to 60 sampling points; and removing outliers using a "mutation rate threshold + 3σ outlier removal" method.

[0036] When at least two microwave humidity sensors are installed at the same location, the moisture content is obtained by weighted fusion, and the weights are adaptively updated based on the self-diagnostic status and historical variance; a linear calibration model is used. Calibrate the moisture content and the coefficient Updated every 8–24 hours based on the control sample.

[0037] Furthermore, in step S6, the steady-state criterion is set as follows: After maintaining the steady-state condition for 60–300 seconds, the fluctuation of the material conveyor belt speed is limited to ≤±5%, and the fluctuation of the opening of the hot air pipe valve and the waste heat recovery pipe valve is limited to ≤±5% to stabilize the fluctuation of the output moisture content.

[0038] In three aspects, the technical solution of the present invention to solve the above-mentioned technical problems is as follows: a fluidized solidified soil prepared from construction waste, characterized in that, by mass parts, it comprises:

[0039] 50-85 parts of recycled fine aggregate prepared from soil that has been solidified using construction waste;

[0040] 10-25 parts of cementitious material;

[0041] 3-20 parts of mineral admixtures;

[0042] Additive 0.05–2.0 parts, mixing water 8–25 parts;

[0043] The target moisture content is controlled between 3% and 8%.

[0044] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0045] 1. Achieve rapid, uniform, and continuous drying of recycled fine aggregates from construction waste, significantly improving the controllability of subsequent proportioning and land efficiency. Through a combination of "pretreatment (retaining only mortar particles, concrete fine aggregates, and brick powder) + pre-dehydration (discharge moisture content ≤14%) + main drying system," the free water load is first reduced before the aggregates enter a vertically arranged high-temperature drying zone—high-temperature buffer zone—insulated discharge zone. Each zone employs at least two sets of material conveyor belts with evenly distributed hot air vents at the top, forming stable heat and mass transfer conditions: the high-temperature zone provides strong evaporation driving force, the buffer zone suppresses local over-drying, clumping, and dust generation, and the insulated zone smooths out fluctuations in discharge moisture content, making it easier for the recycled fine aggregate moisture content to stabilize within the target range of 3%–8%. This provides a repeatable raw material state for subsequent water addition and cementitious material dosage, and the three-dimensional zoning reduces overall land occupation and enables continuous processing.

[0046] 2. Waste heat cascade recovery and reuse, combined with dust entrainment suppression, reduces energy consumption and minimizes pollution and maintenance costs in the heat exchange system. Moist, hot air is drawn from near the bottom of the insulated discharge area into the recovery channel. After sensible and latent heat are recovered by the heat exchange equipment, heated air is distributed through waste heat recovery pipes to multiple waste heat inlets facing the conveyor belt for secondary drying and insulation. This reduces the load on the main heat source and energy consumption per unit output at the system level. Simultaneously, inclined dust baffles are installed in the recovery channel, staggered on both sides, causing the moist, hot airflow to undergo at least two deflections and induce sedimentation and separation. This significantly reduces the probability of dust entering the heat exchange equipment with the airflow, preventing heat exchange efficiency degradation and increased wind resistance due to dust accumulation in the heat exchanger. This enhances the long-term stability and safety of waste heat recovery, achieving a comprehensive effect of "energy saving + dust prevention + reduced operation and maintenance."

[0047] 3. Based on a cascade closed-loop control system of "moisture content outer loop - temperature and humidity inner loop," the system stabilizes and converges the discharge moisture content while ensuring the consistency of the quality of the fluidized solidified soil. Microwave humidity sensors and temperature and humidity sensors for each zone are introduced at key stages of drying and mixing. The main controller filters, calibrates, and fuses the signals before executing cascade control at 0.5–5 s cycles: the outer loop maintains the target moisture content. Based on a baseline of (3%–8%), the conveyor belt speed and hot air valve opening are dynamically adjusted; the inner ring separately constrains the temperature and relative humidity settings of the high-temperature zone / buffer zone / insulation zone, and coordinates the waste heat valve opening to achieve optimal distribution of hot air and waste heat. This is combined with steady-state criteria ( After maintaining a constant speed of 60–300 seconds, the fluctuation range of speed and valve position is limited to ≤±5%, which can compress the fluctuation of the output moisture content to a controllable range, significantly reduce the error of manual experience adjustment and water distribution, and make the actual water-cement ratio of recycled fine aggregate, cementitious materials, mineral admixtures and additives more stable, thereby improving the batch consistency of fluidity and strength of fluidized solidified soil. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the overall structure of the main drying system of the present invention;

[0049] Figure 2 This is a schematic diagram of the overall structure of the equipment for preparing fluidized solidified soil using construction waste according to the present invention;

[0050] Figure 3 This is a schematic diagram illustrating the coordinated allocation of the closed-loop control algorithm and execution quantities of the present invention.

[0051] Figure 4 This is a schematic diagram of the process for preparing fluidized solidified soil using construction waste according to the present invention;

[0052] Figure 5 This is a schematic diagram of the pretreatment closed-loop process structure of the present invention;

[0053] Figure 6 This is a schematic diagram of the three-section vertical partitioning of the main drying section and the multi-belt conveying and hot air supply of the present invention;

[0054] Figure 7 This is a schematic diagram of the waste heat recovery and dust baffle sedimentation structure of the present invention;

[0055] Figure 8 This is a block diagram illustrating the closed-loop control algorithm and execution quantity coordination allocation principle of the present invention.

[0056] Attached reference numerals: 1. Main drying system; 11. High-temperature drying zone; 12. High-temperature buffer zone; 13. Insulated discharge zone; 14. Material conveyor belt; 15. Hot air outlet; 16. Recovery channel; 17. Dust baffle; 2. Auxiliary material adding device; 3. Water adding device; 4. Mixing equipment. Detailed Implementation

[0057] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0059] Example 1:

[0060] refer to Figures 1-3 An apparatus for preparing fluidized solidified soil using construction waste, comprising:

[0061] The pre-processing module includes a crusher, a magnetic separator, and a manual sorting line. The crusher can be a jaw crusher, a screw crusher, or an extrusion crusher, depending on the needs. The magnetic separator can be a self-unloading electromagnetic separator. The pre-processing module crushes, sorts, and screens construction waste to remove impurities such as metal, plastic, fabric, rubber, and wood, retaining only mortar particles, concrete fine aggregate, and brick powder.

[0062] The pre-dehydration module is used to pre-dehydrate the material output from the pretreatment module, so that the output moisture content is controlled at ≤14%.

[0063] It also includes a main drying system 1, an auxiliary material adding device 2 and a water adding device 3, and a mixing device; the mixing device is used to mix the materials processed by the main drying system 1, the auxiliary materials added by the auxiliary material adding device 2 and the mixing water added by the water adding device 3;

[0064] The main drying system 1 includes a high-temperature drying zone 11, a high-temperature buffer zone 12, and an insulated discharge zone 13 arranged vertically. The high-temperature drying zone 11, the high-temperature buffer zone 12, and the insulated discharge zone 13 are constructed of steel or reinforced concrete and wrapped with insulation material on the outside. The material processed by the pre-dehydration module is lifted into the high-temperature drying zone 11 by a lifting device. The top of the high-temperature drying zone 11 has a feed inlet for material entry. The high-temperature drying zone 11, the high-temperature buffer zone 12, and the insulated discharge zone 13 each include at least two sets of material conveyor belts 14. Multiple hot air vents 15 are evenly arranged on the top of the high-temperature drying zone 11. The multiple hot air vents 15 are connected by hot air pipes. The inlet of the hot air pipes is connected to the air chamber heated by the heat source. Natural gas, biomass fuel, electricity, solar energy, etc. can be used to heat the air, and then a fan is used to transport the heated air into the hot air pipes.

[0065] A recovery channel 16 is provided on one side of the main drying system 1, which is connected to the bottom of the insulated discharge area 13. An inclined dust baffle 17 is provided in the recovery channel 16. The top of the recovery channel 16 is connected to a heat exchange device. The air heated by the heat exchange device is delivered to a waste heat recovery pipe, which is connected to multiple waste heat ports facing the material conveyor belt 14. The dust baffle 17 extends downwards at an incline from the side wall of the recovery channel 16 towards the middle. A set of dust baffles 17 is provided on each side of the inner wall of the recovery channel 16, and the dust baffles 17 on both sides are staggered. This causes the humid and hot air in the recovery channel 16 to form at least two deflections and sedimentation separation along the inclined guide and dust baffle structure staggered on both sides of the recovery channel 16, so as to prevent dust from being carried back into the heat exchange device.

[0066] It also includes a main controller; a microwave humidity sensor is installed on the material conveyor belt 14 to obtain the humidity of the material on the material conveyor belt 14 and send it to the main controller; temperature and humidity sensors are installed in the high temperature drying zone 11, the high temperature buffer zone 12 and the heat preservation discharge zone 13 to detect the ambient temperature and humidity in the area and send them to the main controller; the main controller controls the speed of the material conveyor belt 14 and the opening degree of the valves of the hot air pipe and the waste heat recovery pipe according to the humidity of the material, the ambient temperature and humidity.

[0067] Specifically, the auxiliary material adding device 2 is used to precisely combine the material processed by the main drying system 1 with the necessary auxiliary materials according to the ratio, the water adding device 3 is used to precisely add mixing water according to the moisture content of the material, and the mixing equipment is used to fully and evenly mix the material output from the main drying system 1, the auxiliary materials added by the auxiliary material adding device 2, and the water added by the water adding device 3.

[0068] Furthermore, the auxiliary material adding device 2 includes multiple auxiliary material storage units, a metering and feeding unit, a mixing and conveying unit, a weighing / flow detection unit, and a cleaning and maintenance device; each auxiliary material storage unit is equipped with a storage bin for storing different auxiliary materials, and the bottom of the storage bin is equipped with a controllable opening and closing valve, and the bin body is equipped with a moisture-proof and ventilation device; the metering and feeding unit is equipped with a screw feeder or a vibrating feeder and is linked to a weighing sensor, which is used to detect the actual output mass of the auxiliary materials; a material collection hopper is set at the outlet of each metering and feeding unit to collect the various auxiliary materials, and the bottom of the material collection hopper is equipped with a lifting and conveying pipe, which is connected to the inlet of the mixing equipment;

[0069] When the auxiliary material adding device 2 is working, the main controller controls the start and speed of each feeder according to the current humidity of the dried material, the set auxiliary material ratio and the production cycle. The weighing / flow detection unit continuously feeds back the real-time auxiliary material feeding amount to the main controller. The main controller adjusts the output of each metering and feeding unit accordingly to achieve accurate addition of auxiliary materials. After the auxiliary materials are collected by the material collection hopper, they are transported to the designated feeding position of the mixing equipment through the lifting conveying pipeline.

[0070] Furthermore, the water supply device 3 includes a water source unit, a metering water supply unit, a water pipeline and nozzle assembly, and water pressure / temperature detection sensors. The water source unit includes a clean water tank, a circulating pump, and a filter, the filter being used to ensure water supply quality. The metering water supply unit includes a solenoid valve, a high-precision flow meter, and a booster pump; the solenoid valve is driven by the main controller. The water pipeline extends from the water source unit to the feed inlet of the mixing equipment, and multiple spray nozzles are provided at the feed inlet to evenly spray water into the mixing equipment. The water pressure / temperature detection sensors are respectively installed at the water source outlet and the nozzle positions to continuously monitor the water supply status and provide feedback to the main controller.

[0071] The control process of the water adding device 3 is as follows: the microwave humidity sensor obtains the moisture content of the material on the conveyor belt in real time and sends it to the main controller. The main controller calculates the water adding demand based on the target moisture content, the current moisture content and the inner loop control logic of the temperature and humidity of the area, controls the opening of the solenoid valve and the output of the pressurizing pump, and the flow meter continuously feeds back the actual water adding amount to the main controller, thereby realizing closed-loop precise control of the water adding amount.

[0072] Furthermore, the mixing equipment adopts a dual-shaft paddle forced mixer. The mixer includes a horizontally placed cylindrical body shell, with wear-resistant lining plates on the inner wall, and two parallel paddle shafts. The paddle shafts are driven by variable frequency motors. The paddles are arranged in a combination of forward-pushing and backward-pulling to enhance the shearing and mixing effect. The mixer has three feed inlets on the body, which are respectively connected to the outlet of the main drying system 1, the conveying pipeline of the auxiliary material adding device 2, and the water adding nozzle. A flap-type discharge valve is provided at the bottom of the mixing chamber for rapid unloading after mixing. The mixing chamber is also equipped with a humidity probe, a load sensor, and a temperature sensor to monitor the mixing status and provide feedback to the main controller.

[0073] When the mixing equipment is running, it receives dry materials, auxiliary materials and water from the three feed inlets. The twin-shaft paddles mix the materials according to the preset process curve. The internal humidity probe and load sensor continuously feed back the mixing status parameters to the main controller. The main controller adjusts the twin-shaft speed and water addition according to these parameters to ensure the uniformity of mixing. After the mixing reaches the set time or the sensor judgment threshold, the main controller controls the discharge valve to open automatically, so as to achieve the final discharge of the material.

[0074] This embodiment proposes a novel hardware and software structure that differs from traditional single PLC control, used to achieve cascade control and batching linkage control of "material moisture content outer loop - regional temperature and humidity inner loop". The main controller includes a data acquisition unit, a control and calculation unit, and an execution control unit, and adopts a three-layer architecture of "safe real-time control layer + edge intelligent computing layer + field distributed I / O layer": the data acquisition unit consists of distributed I / O modules and multi-source sensors, responsible for monitoring the microwave humidity sensor signals on the material conveyor belt 14 of the main drying system 1, the temperature and humidity sensor signals of each section, the valve positions and fan status of the hot air / waste heat pipeline, the mass flow rate of the main material (belt scale / weighing feeder), the metering feedback of auxiliary materials (loss-in-weight scale / weighing screw), and the feedback from the water flow meter and the admixture metering pump. Synchronous data acquisition is performed. The control and computing unit is composed of an industrial computer IPC or edge controller and a real-time control PLC. The PLC is responsible for millisecond-level execution and interlock protection, while the IPC is responsible for model calculation, parameter self-tuning, formula management, and data recording. The execution control unit is connected to the 14 frequency converter drivers of the material conveyor belt, the electric actuators of the hot air duct valves, the electric actuators of the waste heat recovery duct valves, the frequency converters of the fans in each section, the driver of the auxiliary material screw metering machine, the regulating valve / metering pump of the water addition device 3, and the frequency converter of the main motor of the mixer to realize multi-object closed-loop regulation and cross-system linkage.

[0075] In terms of signal processing, the data acquisition unit filters, calibrates, and fuses the signals from the microwave humidity sensor and the temperature and humidity sensor: the humidity signal is filtered by a sliding window and outlier removal is performed, and dynamic compensation is performed in combination with the material layer thickness / conveying speed; the temperature and humidity signals are calculated to determine the dew point or absolute moisture content to characterize the evaporation driving force; and weighted fusion is used for multiple sensors in the same section to reduce the impact of local disturbances. The control unit implements cascade control logic accordingly: The target moisture content of the material on the material conveyor belt 14 is used as the outer loop setpoint. The outer loop outputs control quantities based on the deviation between the target moisture content and the online measured moisture content. This output is used to correct the speed of the material conveyor belt 14 and the opening of the hot air duct valve in the high-temperature drying zone 11, thereby prioritizing the adjustment of the material's heating time and primary hot air supply. The area temperature and humidity setpoints of the inner loop are used to coordinate and allocate the hot air supply and waste heat supply to the high-temperature drying zone 11, the high-temperature buffer zone 12, and the insulated discharge zone 13, respectively. This ensures that the high-temperature drying zone 11 prioritizes evaporation driving force, the high-temperature buffer zone 12 is used to suppress local over-drying and dust (by reducing the temperature gradient, increasing local relative humidity, or increasing waste heat flexible compensation), and the insulated discharge zone 13 is used to stabilize the discharge moisture content fluctuation and reduce the sensitivity of the discharge to changes in ambient humidity. The outputs of the outer and inner loops, through the execution control unit, form a closed-loop regulation of the valve opening, fan speed, and conveyor belt linear speed, avoiding the oscillation of "over-drying—re-moistening—re-over-drying" caused by adjusting a single variable.

[0076] To meet the general engineering requirements and match the aforementioned pre-dehydration indicators, the typical operating parameters in this embodiment are set as follows: the feed moisture content entering the main drying system 1 after pre-dehydration is 10% to 14% (mass fraction); the target discharge moisture content of the main drying system 1 (i.e., the outer ring target moisture content) is preferably 6% to 10%, and more typically 8% to 9%, to balance the controllability of water addition required for subsequent mixing and the risk of dust; when the feed moisture content is detected to rise briefly (e.g., from 10% to 14%), the outer ring prioritizes reducing the speed of the material conveyor belt 14 and increasing the hot air supply to the high-temperature drying zone 11, while the inner ring simultaneously increases the temperature setting and dehumidification capacity of the high-temperature drying zone 11 and appropriately increases the ambient humidity setting in the high-temperature buffer zone 12 to suppress dust caused by rapid surface drying; when the discharge moisture content is detected to be below the lower limit (e.g., below 6%), the outer ring increases the conveyor belt speed and reduces the opening of the hot air valve, while the inner ring increases the flexible supply of waste heat in the heat-insulated discharge zone 13 to stabilize the material temperature and avoid re-hygroscopic fluctuations caused by a sudden drop in temperature.

[0077] In the "drying and discharging - batching - mixing" linkage, after obtaining the mass flow rate of the main material and the moisture content of the discharge, the main controller performs feedforward calculations on the auxiliary materials and water according to the formula target and superimposes closed-loop corrections: the auxiliary material addition device 2 adds the cementitious material according to the set dosage (the commonly used range in engineering is 8% to 25% of the dry basis mass of the main material, of which the ratio of cement and mineral admixtures is configured according to the strength and fluidity targets) using a loss-in-weight metering method; the water addition device 3 meteres and supplies water according to the total water volume required for the "target slurry workability" minus the water volume carried by the main material, and makes slight corrections to the water addition amount based on the torque / current characteristics of the mixing motor and the discharge stability during the mixing process, so as to maintain the uniformity of the slurry and the pumpable / flowable performance under the condition of raw material fluctuations. The fluidized solidified soil after mixing can be directly pumped or conveyed by chute, which is suitable for backfilling scenarios such as foundation pits and trenches.

[0078] Through the above structure and control method, this embodiment achieves quantitative, closed, and traceable addition of auxiliary materials and water at the hardware level, and stabilizes the moisture content of the dried material at the software level through cascade control of "moisture content outer loop - temperature and humidity inner loop". At the same time, by utilizing a new hardware and software structure of "PLC real-time interlocking + IPC edge intelligent computing + distributed I / O", the drying section control and the batching and mixing section are linked, so that even within the normal fluctuation range of feed moisture content of 10% to 14%, the moisture content of the dried material can still be stably controlled within the target range of 6% to 10% (typically 8% to 9%), and provide a stable material foundation and a controllable water addition window for subsequent mixing and preparation of fluidized solidified soil.

[0079] In a preferred embodiment, in order to adapt to the normal fluctuation of the moisture content of the material after pre-dehydration (10% to 14% by mass) and to stably control the moisture content of the main drying system 1 at 6% to 10% (typically 8% to 9%), the main controller sets temperature and humidity control targets for the high-temperature drying zone 11, the high-temperature buffer zone 12 and the heat-insulated discharge zone 13, and sets executable limit ranges for the speed of the material conveyor belt 14 and the opening of the hot air / waste heat valve. Specifically, the hot air temperature setting T1 of the high-temperature drying zone 11 is preferably 120-180℃ (more typically 130-170℃) to provide the main driving force for evaporation; the ambient temperature setting T2 of the high-temperature buffer zone 12 is preferably 80-140℃ (more typically 90-120℃) to suppress local over-drying and reduce dust tendency; the ambient temperature setting T3 of the heat-insulating discharge zone 13 is preferably 50-100℃ (more typically 60-85℃) to smooth the fluctuation of discharge moisture content and avoid the instability of re-moistening caused by sudden temperature changes at the material discharge end. To facilitate the characterization of dehumidification capacity and evaporation driving force, relative humidity and / or dew point temperature can be used to characterize the humidity control in each section: the dew point temperature setpoint Td1 of the high-temperature drying zone 11 is preferably 20-45℃, the dew point temperature setpoint Td2 of the high-temperature buffer zone 12 is preferably 30-55℃, and the dew point temperature setpoint Td3 of the heat-insulated discharge zone 13 is preferably 35-60℃; when relative humidity is used for characterization, the relative humidity setpoints of the high-temperature buffer zone 12 and the heat-insulated discharge zone 13 can be 30%-60% and 40%-70% respectively, so as to achieve the division of labor of "enhanced evaporation in the drying zone, dust suppression and steady-state in the buffer zone, and anti-fluctuation in the discharge zone".

[0080] Regarding the operating range, the linear speed v of the material conveyor belt 14 is preferably set between 0.08 and 0.80 m / min (more typically 0.10 to 0.60 m / min). Specifically, when the microwave humidity sensor detects that the feed moisture content is close to the upper limit (e.g., ≥13%), the outer ring preferentially lowers v to the 0.08–0.35 m / min range to prolong the heating time; when the output moisture content is detected to be trending below the lower limit (e.g., ≤6.5%), the outer ring preferentially raises v to the 0.35–0.80 m / min range to avoid excessive dryness. The opening degree αh of the hot air duct valve (based on 0–100%) is preferably controlled between 15% and 100% (more typically 25%–95%), and the opening degree αw of the waste heat recovery pipe valve is preferably controlled between 0% and 80% (more typically 5%–70%). To reflect the priority of heat distribution in the three zones, the main controller can prioritize the hot air supply to the high-temperature drying zone 11: the opening degree of the hot air branch valve corresponding to the high-temperature drying zone 11 is preferably 40% to 100%, the opening degree of the hot air branch valve corresponding to the high-temperature buffer zone 12 is preferably 15% to 60%, and the opening degree of the hot air branch valve corresponding to the insulated discharge zone 13 is preferably 10% to 45%; the waste heat supply is prioritized for the flexible compensation of the high-temperature buffer zone 12 and the insulated discharge zone 13: the opening degree of the waste heat branch valve corresponding to the high-temperature buffer zone 12 is preferably 10% to 70%, the opening degree of the waste heat branch valve corresponding to the insulated discharge zone 13 is preferably 5% to 55%, and the opening degree of the waste heat branch valve corresponding to the high-temperature drying zone 11 is preferably 0% to 35%. When the fan drive is frequency-controlled, the frequency f of the circulating fan / exhaust fan in each section is preferably 20-60 Hz (more typically 30-50 Hz), and can be coordinated with the valve opening to limit the amplitude, so as to avoid the unfavorable working conditions of "valve opening too wide but insufficient air volume" or "excessive air volume causing dust".

[0081] Furthermore, to ensure the stability and feasibility of closed-loop regulation, the main controller sets slope limits for the rate of change of the executed quantity: the rate of change of the hot air valve opening and the waste heat valve opening is preferably no more than 5% to 15% / s, and the rate of change of the material conveyor belt speed is preferably no more than 0.02 to 0.10 m / min·s; the control cycle is preferably 1 to 5 s, and the humidity signal filtering window is preferably 10 to 30 s, to suppress the high-frequency jitter introduced by the microwave humidity sensor when the material layer thickness fluctuates or the particle size distribution changes. Through the above parameter range setting and cascade control logic, under common operating conditions of ambient temperature 10 to 35℃ and ambient relative humidity 30% to 85%, stable control of the discharge moisture content within the target range can be achieved without increasing manual intervention, and a stable "controllable water window" can be provided for subsequent quantitative addition of auxiliary materials and water mixing.

[0082] In a preferred embodiment, the main controller divides the feed moisture content w_in (mass fraction) entering the high-temperature drying zone into three levels: Level A is 10%–12%, Level B is 12%–13%, and Level C is 13%–14%. Based on the outer loop (moisture content) output, the main controller combines the inner loop (regional temperature and humidity) to adopt a level-limited and zone-based heat distribution strategy for each execution quantity. This ensures that the high-temperature drying zone prioritizes providing evaporation driving force, the high-temperature buffer zone is used for dust suppression and to prevent local over-drying, and the heat-insulating discharge zone is used to stabilize the fluctuation of the discharge moisture content.

[0083] A file: = 10%~12% (low / medium moisture content)

[0084] This section focuses on "avoiding over-drying and stabilizing material output." The outer ring controls prioritize improving conveying efficiency and reducing the intensity of primary hot air, while the inner ring uses waste heat flexible compensation to stabilize the end.

[0085] Conveyor belt linear speed v: 0.35~0.80 m / min (typically 0.45~0.65);

[0086] Three-zone temperature settings: High-temperature drying zone T1: 120~150℃ (typically 130~145℃); High-temperature buffer zone T2: 80~110℃ (typically 90~105℃); Insulated discharge zone T3: 55~80℃ (typically 60~75℃);

[0087] Hot air valve opening αh (0~100%): 25%~60% (typically 30%~50%);

[0088] Recommended allocation: 40%–70% for drying zone branches; 15%–40% for buffer zone; 10%–30% for discharge zone.

[0089] Waste heat valve opening αw (0~80%): 10%~55% (typically 20%~45%);

[0090] Recommended allocation: buffer zone 20%–60%; discharge zone 15%–50%; drying zone 0%–20%;

[0091] Fan frequency f: 25~45 Hz (typically 30~40 Hz);

[0092] Category B: = 12%~13% (medium to high moisture content);

[0093] This setting represents the common operating condition, which focuses on "balancing drying intensity and dust risk". The outer ring uses moderately slowed and moderately heated air, while the inner ring maintains the humidity / dew point of the buffer zone to suppress dust.

[0094] Conveyor belt linear speed v: 0.20~0.55 m / min (typically 0.28~0.45);

[0095] Three-zone temperature settings: High-temperature drying zone T1: 140~170℃ (typically 150~165℃); High-temperature buffer zone T2: 90~125℃ (typically 100~115℃); Insulated discharge zone T3: 60~90℃ (typically 65~80℃);

[0096] Hot air valve opening αh: 45%~85% (typically 55%~75%);

[0097] Recommended allocation: 60%–95% for drying zone branches; 20%–55% for buffer zone; 15%–40% for discharge zone;

[0098] Waste heat valve opening αw: 5%~65% (typically 15%~50%);

[0099] Recommended allocation: buffer zone 15%–70%; discharge zone 10%–55%; drying zone 0%–25%;

[0100] Fan frequency f: 30–55 Hz (typically 35–48 Hz);

[0101] C-level: = 13%~14% (high moisture content, most unfavorable working condition);

[0102] This mode focuses on "enhancing evaporation driving force and dehumidification". The outer ring prioritizes significantly reducing speed and increasing hot air supply; the inner ring enhances the temperature and dehumidification capacity of the drying zone, while keeping the buffer zone from becoming too dry and generating dust.

[0103] Conveyor belt linear speed v: 0.08~0.35 m / min (typically 0.12~0.25)

[0104] Three-zone temperature settings: High-temperature drying zone T1: 160~180℃ (typically 165~175℃); High-temperature buffer zone T2: 110~140℃ (typically 115~130℃); Insulated discharge zone T3: 70~100℃ (typically 75~90℃).

[0105] Hot air valve opening αh: 70%~100% (typically 80%~95%);

[0106] Recommended allocation: 85%–100% for drying zone branches; 35%–65% for buffer zone; 20%–45% for discharge zone;

[0107] Waste heat valve opening αw: 0%~50% (typically 5%~35%);

[0108] Recommended allocation: buffer zone 10%–55%; discharge zone 5%–40%; drying zone 0%–20%;

[0109] In this section, waste heat is supplemented by "flexible compensation" to avoid diluting the evaporation capacity of the primary hot air;

[0110] Fan frequency f: 40~60 Hz (typically 45~55);

[0111] In a further preferred embodiment, to avoid frequent switching caused by fluctuations in the feed moisture content near the gear boundary, the main controller sets hysteresis for gear switching: when When the threshold changes from low to high, the switching threshold from A to B is ≥12.2%, and the switching threshold from B to C is ≥13.2%. When the flow rate decreases from high to low, the cut-back threshold for C→B is ≤13.0%, and the cut-back threshold for B→A is ≤12.0%. Simultaneously, change rate limits are set for the execution variables: the change rates of αh and αw do not exceed 5%–15% / s, the change rate of v does not exceed 0.02–0.10 m / min·s, and the control cycle is 1–5 s, to ensure the stability of the cascade closed loop.

[0112] Example 2:

[0113] refer to Figure 4 , 6 7 and 8, a method for preparing fluidized solidified soil using construction waste, using the equipment of Example 1, includes the following specific steps:

[0114] S1. Pre-treatment: The construction waste is crushed, sorted and screened to retain only mortar particles, concrete fine aggregates and brick powder to obtain pre-treated materials.

[0115] S2. Pre-dehydration: The pretreated material is pre-dehydrated to ensure that the moisture content of the pre-dehydrated output is ≤14%;

[0116] S3. Main Drying: The pre-dehydrated material is lifted to the high-temperature drying zone of the main drying system by a lifting device, and the material is dried sequentially through the high-temperature drying zone, the high-temperature buffer zone and the heat-insulated discharge zone set in the vertical direction; at least two sets of material conveyor belts are used to transport the material in the high-temperature drying zone, the high-temperature buffer zone and the heat-insulated discharge zone respectively; hot air is sent into multiple hot air vents evenly arranged at the top of the high-temperature drying zone, and the multiple hot air vents are connected by hot air pipes, and the inlet of the hot air pipes is connected to the air chamber heated by the heat source;

[0117] S4. Waste heat recovery and reuse: Moist and hot air is drawn from near the bottom of the heat-insulated discharge area into the recovery channel, and the moist and hot air is heated by heat exchange equipment to form heated air. The heated air is delivered to the waste heat recovery pipe and sprayed out from multiple waste heat ports connected to the waste heat recovery pipe towards the material conveyor belt to participate in drying and heat preservation.

[0118] S5. Mixing: The dried material, the auxiliary materials added by the auxiliary material adding device, and the mixing water added by the water adding device are sent into the mixing equipment for mixing to obtain fluidized solidified soil.

[0119] S6. Closed-loop control: During steps S3 to S5, the material moisture content is collected from the microwave humidity sensor on the material conveyor belt at a control cycle of 0.5 to 5 seconds. The ambient temperature is obtained from temperature and humidity sensors in the high-temperature drying zone, high-temperature buffer zone, and insulated discharge zone. With relative humidity And execute the cascade closed-loop control algorithm of "material moisture content outer loop - regional temperature and humidity inner loop":

[0120] With target moisture content Construct an outer ring with a moisture content of 3%–8%, based on the moisture content error. Calculate the outer loop control variable and adjust the setpoint of the material conveyor belt speed accordingly. With hot air duct valve opening setting value Make corrections, among which The speed limit is within the range of 0.05 to 2.00 m / s. The limit is between 10% and 100%;

[0121] The temperature and humidity of each zone are controlled in a closed-loop manner using an inner ring system. The high-temperature drying zone is set to a temperature of 110–180℃ and a relative humidity of 5%–25%; the high-temperature buffer zone is set to a temperature of 70–120℃ and a relative humidity of 15%–45%; and the insulated discharge zone is set to a temperature of 40–80℃ and a relative humidity of 25%–60%. The opening degree of the waste heat recovery pipe valves is then coordinated and allocated accordingly. ,make The limit is within the range of 0% to 100%;

[0122] Thus, by implementing closed-loop regulation of the material conveyor belt speed, the hot air duct valve opening, and the waste heat recovery duct valve opening, the discharge moisture content can be stably converged to the target moisture content range.

[0123] Furthermore, as a preferred embodiment, in step S4, the humid and hot air in the recovery channel is deflected at least twice along the inclined guide and dust-blocking structures arranged alternately on both sides of the recovery channel, resulting in sedimentation and separation, so as to suppress dust entrainment and re-entry into the heat exchange equipment.

[0124] Furthermore, as a preferred embodiment, the filtering, calibration, and fusion of sensor signals in step S6 includes at least one of the following: applying first-order low-pass or moving average filtering to the moisture content, temperature, and humidity signals with a filtering window of 5 to 60 sampling points; and using "mutation rate threshold + 3σ outlier removal" to remove outliers.

[0125] When at least two microwave humidity sensors are installed at the same location, the moisture content is obtained by weighted fusion, and the weights are adaptively updated based on the self-diagnostic status and historical variance; a linear calibration model is used. Calibrate the moisture content and the coefficient Updated every 8–24 hours based on the control sample.

[0126] Furthermore, as a preferred embodiment, the steady-state criterion is set as follows in step S6: After maintaining the steady-state condition for 60–300 seconds, the fluctuation of the material conveyor belt speed is limited to ≤±5%, and the fluctuation of the opening of the hot air pipe valve and the waste heat recovery pipe valve is limited to ≤±5% to stabilize the fluctuation of the output moisture content.

[0127] Example 3:

[0128] refer to Figures 4-8 A method for preparing fluidized solidified soil using construction waste, employing the equipment described in Example 1, includes the following specific steps:

[0129] S1 Pretreatment (Crushing—Impurity Removal—Screening—Closed Loop): After construction waste enters the pretreatment module, it undergoes feeding, crushing, impurity removal, and screening in sequence to obtain pretreated material containing only mortar particles, concrete fine aggregate, and brick powder.

[0130] 1) Feeding and coarse sorting: Construction waste is unloaded into the feeding hopper and continuously transported by a chain conveyor or belt conveyor; manual sorting positions or grid screens are set up on the conveying path to preferentially remove large pieces of wood, plastic film, fabric and large debris, so as to reduce the subsequent crushing load and avoid entanglement and blockage.

[0131] 2) Crushing and Disintegration: The pretreatment module uses a combination of primary crushing and secondary shaping (e.g., jaw crusher / impact crusher) to fully disintegrate concrete blocks, mortar blocks, and bricks. Primary crushing mainly controls the output particle size (e.g., ≤40~60mm), while secondary crushing / shaping further reduces the particle size and increases the freshness of the particle surface, improving the uniformity of subsequent drying and mixing.

[0132] 3) Iron removal and light material removal: A magnetic separator (permanent magnet drum or suspended electromagnetic separator) is installed in the conveying section after crushing to remove magnetic metals such as steel bars and nails; an air separation or airflow separation unit is installed before or after screening to remove light impurities such as plastics, paper scraps, and foam, so as to prevent them from entering the drying system and causing odor and blockage risks.

[0133] 4) Screening and Closed-Loop Circuit: Particles are graded by multi-stage vibrating screens or drum screens, preferably with an upper screen aperture of 10–20 mm and a lower screen aperture of 3–8 mm to form a stable fine particle gradation. Oversized particles are returned to the secondary crushing stage to form a closed-loop circulation; undersized fine powder can be combined with intermediate particle sizes in proportion, ultimately retaining only mortar particles, concrete fine aggregate, and brick powder as pre-treated material output. To ensure uniform drying in the subsequent conveyor belt, the maximum particle size of the pre-treated material is preferably controlled to ≤10–20 mm, and screening controls fluctuations in the fine particle gradation.

[0134] S2 Pre-dehydration (mechanical dehydration - online verification - moisture content ≤14%): Pre-dehydration is performed on the pre-treated material to ensure that the moisture content of the pre-dehydrated output is ≤14%, and preferably stable at 10% to 14%.

[0135] 1) Selection of dewatering method: The pre-dewatering module can adopt mechanical dewatering methods such as screw extrusion dewatering, belt press dewatering or centrifugal dewatering; when the material has a high powder content and is prone to clogging, screw extrusion or belt press is preferred, and a uniform agitator is set at the feeding end to make the moisture content of the material more evenly distributed.

[0136] 2) Dehydration condition adjustment: By adjusting parameters such as pressing pressure / screw speed, residence time in the pressing section, and filter belt tension, the dehydrated material can be discharged continuously and stably. If necessary, without introducing additional chemical dependence, a mechanical strategy of "segmented pressing + short-time remixing" can be adopted to reduce fluctuations in the drying section caused by local high moisture content.

[0137] 3) Moisture content verification and qualification judgment: A sampling port is set at the pre-dewatering discharge point and online or offline moisture content detection is combined (calibration samples can be shared with the subsequent S6 collection system). "≤14%" is used as the qualification judgment threshold. If the detected value is >14%, the deviation is corrected by reducing the discharge amount, extending the pressing time, or increasing the pressing intensity until it is stable and qualified before entering S3.

[0138] The S3 main drying section (three-section vertical partitioning—multi-belt conveyor—hot air supply) lifts the pre-dehydrated material to the high-temperature drying zone of the main drying system via an elevator, and then sequentially passes through the high-temperature drying zone, high-temperature buffer zone, and insulated discharge zone to complete the drying process. Each of the three sections uses at least two sets of material conveyor belts to transport the material, achieving layered material distribution, segmented heat exchange, and zoned humidity control.

[0139] 1) Feeding and homogenization: After the pre-dehydrated material enters the high-temperature drying zone through the lifting equipment, it is first evenly spread on the surface of the material conveyor belt by a distributor or a uniform distribution gate. The preferred thickness of the spread material is 20-80mm (more typically 30-60mm) to avoid excessive thickness which restricts internal moisture migration, or excessive thinness which leads to localized over-drying and increased dust.

[0140] 2) High-Temperature Drying Zone (Evaporation Driving Force): Hot air is supplied to multiple hot air inlets evenly distributed at the top of the high-temperature drying zone. These inlets are connected by hot air ducts, the inlets of which are connected to the air chamber heated by the heat source. The high-temperature drying zone preferably uses a temperature setting of 110–180°C and a relative humidity setting of 5%–25%, allowing the hot air to penetrate the material layer through strong convection, rapidly evaporating surface water and driving internal moisture migration. The residence time of the material in this zone can be adjusted by the conveyor belt speed, typically 3–20 minutes (depending on the feed moisture content and material thickness).

[0141] 3) High-temperature buffer zone (dust suppression and prevention of over-drying): After the material enters the high-temperature buffer zone, the tendency for localized over-drying and dust generation is suppressed by reducing the temperature gradient and appropriately increasing the ambient humidity (70-120℃, 15%-45%RH). In this section, the drying rate of the material surface can be transitioned from "rapid evaporation" to "equilibrium migration" by adjusting the hot air supply and waste heat flexible compensation, thus avoiding the formation of a dry shell that would affect subsequent stable material discharge.

[0142] 4) Insulated Discharge Zone (Steady State and Anti-Fluctuation): After the material enters the insulated discharge zone, a set range of 40-80℃ and 25%-60%RH is used to smooth the material temperature and moisture content, reducing fluctuations in the discharge moisture content and providing a more controllable moisture content window for subsequent mixing. A buffer hopper or flow stabilizer can be installed at the discharge end of the insulated discharge zone to ensure a stable mass flow of the main material entering S5.

[0143] S4 Waste heat recovery and reuse (including humid air extraction - baffle sedimentation - heat exchange - waste heat return port): Humid air is drawn from near the bottom of the insulated discharge area into the recovery channel, so that the humid air is heated after heat exchange equipment; the heated air is delivered to the waste heat recovery pipe and sprayed out from multiple waste heat ports connected to the waste heat recovery pipe towards the material conveyor belt to participate in drying and heat preservation.

[0144] 1) Extraction and organization of humid and hot air: Air inlets are installed at the bottom of the insulated discharge area to allow humid and hot air to enter the recovery channel under slight negative pressure, preventing unorganized escape and accumulation of moisture and heat in the workshop. The air volume is preferably matched with the dehumidification requirements of the main drying system to maintain the controllability of temperature and humidity settings in each section.

[0145] 2) Dust-blocking and sedimentation separation: Inclined dust-blocking structures are staggered on both sides of the recovery channel, causing the humid and hot air to undergo at least two deflections. During the deflection process, the airflow velocity decreases and inertial separation occurs, carrying dust to settle into the dust collection area at the bottom of the channel. This reduces the risk of blockage and heat exchange attenuation caused by dust entering the heat exchange equipment. The dust collection area can be cleaned regularly through the maintenance port, or a dust hopper can be installed for centralized collection.

[0146] 3) Heat exchange and return: The humid and hot air is heated by the heat exchange equipment to form heated air (which can be the heated air side output in the form of air-to-air heat exchange or air-to-water heat exchange) and is delivered to the waste heat recovery pipe; the waste heat recovery pipe is connected to multiple waste heat ports facing the material conveyor belt, and prioritizes to supplement the high temperature buffer zone and the heat preservation discharge zone according to the instructions of the main controller, so as to stabilize the temperature and humidity of the section and reduce the energy consumption of the main heat source in the form of "flexible heat".

[0147] S5 Mixing (Main material stabilization - auxiliary material metering and addition - metering water addition - forced mixing into finished product): The main dried material, the auxiliary materials added by the auxiliary material adding device, and the mixing water added by the water adding device are sent into the mixing equipment for mixing to obtain fluidized solidified soil.

[0148] 1) Main material flow stabilization and metering: After the main drying system discharges into the buffer hopper, a stable mass flow output is achieved through a frequency converter or belt scale to avoid the impact of instantaneous fluctuations in the main material on the batching accuracy and slurry consistency.

[0149] 2) Quantitative addition of auxiliary materials: The auxiliary material addition device measures the cementitious materials and functional admixtures according to the formula (preferably using a weighing screw or loss-in-weight metering), and enters the mixing equipment through a closed conveying method at the addition port; when liquid admixtures are set, they can be injected synchronously through a metering pump to improve dispersibility and reduce agglomeration.

[0150] 3) Mixing water metering and staged addition: The water supply device uses a flow meter / mass flow meter to meter the water supply and adds it in a dispersed manner through a multi-point spray nozzle array; the preferred strategy is to "wet a small amount first and then add the target amount of water" in stages to reduce the risk of clumping and local over-dilution. The mixing water setting can be calculated based on the dry basis mass of the main material and the target workability feedforward, and can be fine-tuned under the S6 closed-loop control output or mixing load feedback.

[0151] 4) Forced mixing and discharge: The preferred mixing equipment is a twin-shaft paddle forced mixing system (intermittent or continuous). Under intermittent conditions, the typical mixing time is 30–180 seconds; under continuous conditions, the typical material residence time in the mixing chamber is 20–120 seconds. After the set mixing time or mixing status criterion is reached, the discharge valve is opened to obtain the finished fluidized solidified soil, which can be directly pumped or chuted to the backfilling site.

[0152] S6 Closed-Loop Control (Further Refined Cascade Closed-Loop Algorithm and Execution Flow): During the continuous operation of steps S3 to S5, the main controller executes a closed-loop control cycle once every 0.5 to 5 seconds (preferably 1 or 2 seconds) with a control period Δt. Within each control cycle, the following process is completed sequentially: "Data Acquisition → Signal Preprocessing → Moisture Content Outer Loop Calculation → Regional Temperature and Humidity Inner Loop Calculation → Execution Quantity Coordination and Allocation → Steady-State Criterion Judgment and Limiting Constraints → Execution Output," to achieve stable convergence of the discharge moisture content to the target moisture content. It is in the range of 3% to 8%.

[0153] S6-1 Data acquisition and time alignment: At the beginning of each control cycle, the main controller synchronously acquires: (1) the raw moisture content value output by the microwave humidity sensor arranged on the material conveyor belt. (2) The original ambient temperatures corresponding to the high-temperature drying zone, high-temperature buffer zone and heat preservation discharge zone respectively. Compared with the original value of relative humidity (i=1, 2, 3); (3) Feedback signals from the actuator, including: actual speed of the material conveyor belt Actual opening degree of hot air duct valve Actual opening degree of waste heat recovery pipe valve It can also optionally collect auxiliary parameters such as fan frequency and inlet / outlet temperature of heat exchange equipment for diagnostic purposes.

[0154] To avoid phase errors caused by asynchronous operation of multiple sensors, the main controller timestamps the above signals and interpolates or holds them with a control period Δt to complete timing alignment.

[0155] S6-2 Signal Filtering, Anomaly Removal and Fusion: The main controller filters, calibrates and fuses moisture content, temperature and humidity signals using at least one of the following methods:

[0156] (1) Filtering: For Using a first-order low-pass filter or moving average filter, with a filter window of 5–60 sampling points (preferably 10–30 sampling points), the following results are obtained. , and .

[0157] (2) Outlier removal: Outliers are handled using a "mutation rate threshold + 3σ outlier removal" method. If the mutation rate exceeds the preset threshold, or if x(k) exceeds the mean of the most recent N points ±3σ, then the point is marked as an anomaly and kept with the most recent valid value or replaced with an interpolated value.

[0158] (3) Multi-sensor fusion: When no less than two microwave humidity sensors are set at the same location, the filtered values ​​of each sensor are fused together. By weight The water content is obtained by fusion Weight The sensor is adaptively updated based on its self-diagnostic status and historical variance: the weight of sensor with abnormal self-diagnostic status is reduced to 0 or to the minimum; the smaller the historical variance, the higher the weight.

[0159] (4) Linear calibration: A linear calibration model is used for moisture content. The calibrated moisture content M is obtained. The coefficients a and b are updated every 8–24 h based on the control sample; within the update interval, a and b are kept constant to suppress drift and ensure control continuity.

[0160] S6-3 Calculation of derived quantities required for inner loop control: To ensure that the temperature and humidity inner loop can reflect the "evaporation driving force," the main controller can optionally calculate segment-specific derived quantities for control criteria and coordinated allocation.

[0161] (1) Based on and Calculate the absolute moisture content or dew point temperature of each section. (2) Calculate the evaporation driving force index For example, the difference between "section temperature and dew point temperature" or "section saturated moisture content and actual moisture content" can be used to determine whether the dehumidification is insufficient and whether there is a risk of excessive dryness and dust.

[0162] The above derived quantities are only used for control calculations and do not change the constraint boundaries of temperature and relative humidity settings.

[0163] S6-4 Moisture content outer loop calculation and setpoint correction, the main controller uses the target moisture content To construct an outer ring, the ratio should be between 3% and 8%, with the optimal choice based on the operating conditions. The moisture content error is 5%–7%. The error is calculated within each control cycle. ; and based on Calculate the outer loop control quantity The outer-loop control law can be a PI or a PID with anti-saturation mechanism, preferably possessing the following mechanism:

[0164] (1) Proportional integral: (2) Resistance to integral saturation: when or When the amplitude limit is reached, the integral term is frozen or inverse calculation is used to resist saturation in order to avoid overshoot caused by long-term saturation; (3) Dead zone: when When the value is less than a small threshold (e.g., 0.1 to 0.3), reduce the integral gain or enter fine-tuning mode to reduce valve jitter.

[0165] The outer loop output is used to simultaneously correct the material conveyor belt speed setpoint. With hot air duct valve opening setting value This forms a coordinated regulation of "time (speed) + heat (hot air)". The preferred allocation method is "main control speed, auxiliary control hot air": (1) When When the moisture content is >0 (too high), prioritize reducing it. And improve (2) When When the moisture content is <0 (too low), prioritize increasing it. and reduce .in, The amplitude is limited to the range of 0.05–2.00 m / s. The amplitude is limited to 10% to 100%; after the amplitude is limited, the output is sent as the execution layer setting value to the frequency converter and valve electric actuator.

[0166] S6-5 Inner-loop closed-loop regulation and zoning targets for temperature and humidity in the S6-5 area: After the outer loop completes setpoint correction, the main controller performs closed-loop regulation of temperature and humidity for the high-temperature drying zone (i=1), high-temperature buffer zone (i=2), and heat-insulating discharge zone (i=3) respectively. The inner-loop setpoints satisfy the following range constraints: High temperature drying zone: Temperature setting: 110–180℃; Relative humidity setting: 5%–25%; High temperature buffer zone: Temperature setting: 70–120℃; Relative humidity setting: 15%–45%; Insulated discharge zone: Set the temperature to 40–80℃ and the relative humidity to 25%–60%.

[0167] The inner loop control preferably adopts a dual-loop structure of "temperature loop + humidity loop":

[0168] (1) Temperature circuit according to Output heat demand ;

[0169] (2) Humidity circuit according to Output dehumidification / heating requirements .

[0170] The high-temperature drying zone prioritizes evaporation drive: when humidity is high and temperature is low, hot air supply is increased and dehumidification is enhanced; the high-temperature buffer zone is used to suppress local over-drying and dust: when temperature is high and humidity is low, waste heat is introduced for flexible compensation and hot air intensity is reduced; the heat-insulated discharge zone is used to stabilize fluctuations: when moisture content tends to fluctuate and amplify, waste heat is used to adjust temperature and humidity gradually to reduce disturbance at the discharge end.

[0171] S6-6 Waste heat valve coordination and allocation and execution quantity synthesis ( (Generation), the main controller outputs based on the inner loop. Generate the set value of the valve opening of the waste heat recovery pipe. and satisfy The limit is between 0% and 100%. In a preferred embodiment, the main controller uses a distribution coefficient to coordinate the waste heat supply in sections:

[0172] (1) First calculate the waste heat demand index of each area. and to Perform normalization;

[0173] (2) Prioritize the allocation of waste heat to the high-temperature buffer zone and the heat preservation discharge zone, and obtain the valve opening of the waste heat branch in each zone. ;

[0174] (3) Total waste heat valve opening As The upstream constraint or total output valve output complements the hot air valve output: when the hot air supply is already at a high level and dust suppression steady state is still required, the output valve is increased. Flexible compensation; when it is necessary to enhance the evaporation driving force, reduce To mitigate the "dilution effect" in the main drying zone, hot air should remain dominant.

[0175] The above-mentioned coordination and allocation ensures clear functional boundaries for the three sections: the high-temperature drying zone prioritizes evaporation, the high-temperature buffer zone prioritizes dust suppression, and the heat-insulating discharge zone prioritizes steady-state operation.

[0176] The linkage correction between the S6-7 and S5 mixing sections (closed-loop consistency at the methodological level) ensures that "stable convergence of dried discharge moisture content" supports "controllable water addition during mixing." The main controller can adjust the outer-loop moisture content error. and its trend volume For fine-tuning the mixing water (without changing the basic steps of S5). In a preferred embodiment:

[0177] (1) When When the value is continuously positive and the trend is upward, the main controller sends a water reduction correction amount ΔW<0 to the water supply device or delays the water supply sequence.

[0178] (2) When When the value remains negative and the trend is downward, the main controller sends a water replenishment correction amount ΔW>0 to the water supply device or adopts segmented water replenishment.

[0179] (3) The above correction amount is set with an upper limit to avoid the excessive compensation of the mixing section from masking the fluctuations of the drying section, thereby maintaining the control responsibility allocation of "drying section as the main part and mixing section as the auxiliary part".

[0180] S6-8 Steady-state criterion, steady-state hold and jitter suppression, the main controller sets the steady-state criterion as follows: The system is maintained continuously for 60–300 s. After the steady-state criterion is met, the system enters the steady-state holding mode and executes the following constraints: (1) Limit the fluctuation of the material conveyor belt speed to ≤±5%; (2) Limit the fluctuation of the opening of the hot air pipe valve and the opening of the waste heat recovery pipe valve to ≤±5%; (3) Appropriately reduce the outer loop integral gain or freeze the integral term, and retain only a small proportional correction to reduce frequent valve operation and system energy consumption fluctuation.

[0181] When steady state is disrupted (e.g.) When the value exceeds 0.5 again and continues for more than the preset time, it will automatically exit the steady-state holding mode and resume normal cascade closed-loop regulation.

[0182] S6-9 Fault Diagnosis and Degradation Control

[0183] In a further preferred embodiment, the main controller performs online diagnostics on the sensors and actuators: when the microwave humidity sensor malfunctions due to self-diagnosis, data not being updated for an extended period, or the proportion of consecutive abnormal points exceeding a threshold, the main controller reduces the sensor's weight to 0 and uses the remaining sensor fusion value or the most recent valid value as the moisture content input; when the temperature and humidity sensor malfunctions, the inner loop switches to a degradation strategy of "temperature priority + conservative humidity," and... and Operating within a safe range is restricted to prevent excessive dryness leading to dust or excessive moisture leading to water accumulation. When the feedback deviation of the actuator (valve / frequency converter) exceeds the threshold, the main controller triggers an alarm and maintains the execution quantity at the most recent stable value or switches to the preset safety setting to ensure production continuity and equipment safety.

[0184] Example 4:

[0185] A fluidized solidified soil material prepared from construction waste is disclosed. It uses recycled fine aggregate obtained by the method in Example 2 or 3 as the main aggregate, combined with cementitious materials, mineral admixtures, additives, and mixing water. It is suitable for engineering applications such as backfilling of pipe trenches, foundation pits, and confined spaces. The fluidized solidified soil comprises, by weight, 50-85 parts recycled fine aggregate, 10-25 parts cementitious materials, 3-20 parts mineral admixtures, 0.05-2.0 parts additives, and 8-25 parts mixing water, with a target moisture content controlled at 3%-8%.

[0186] 1) Raw material composition and preferred types

[0187] (1) Recycled fine aggregate: prepared by the method described in Example 2 or 3. The raw material source is the dried recycled fine aggregate obtained after pretreatment, pre-dehydration, main drying and closed-loop control of construction waste. The main components are mortar particles, concrete fine aggregate and brick powder. The particle size is preferably ≤10~20mm, and the moisture content is stabilized in the range of 3%~8% by the closed-loop control of the equipment to ensure that the subsequent water distribution window is controllable.

[0188] (2) Cementitious materials: Portland cement, ordinary Portland cement, slag Portland cement or a combination thereof may be selected; in order to balance early strength and pumping / flow stability, PO 42.5 grade or equivalent strength grade cement or cement compound system with a small amount of lime / sulfoaluminate cementitious materials is preferred.

[0189] (3) Mineral admixtures: can be fly ash, granulated blast furnace slag powder, silica fume, limestone powder or a combination thereof; preferably, fly ash and slag powder are used to improve workability, reduce bleeding and enhance later strength development.

[0190] (4) Admixtures: can be water-reducing agents, plasticizers, retarders, early strength agents, defoamers, air-entraining agents or combinations thereof; preferably include polycarboxylate water-reducing agents (for obtaining target fluidity at lower mixing water) and a small amount of defoamer (for suppressing strength dispersion caused by bubbles).

[0191] (5) Mixing water: can be tap water, groundwater or recycled water that meets the engineering water requirements, preferably clean water at room temperature, and added under the metering control of the water adding device.

[0192] 2) Proportion range and preferred range (by mass parts): In one embodiment, the fluidized solidified soil comprises, by mass parts: 50-85 parts recycled fine aggregate; 10-25 parts cementitious material; 3-20 parts mineral admixture; 0.05-2.0 parts additive; and 8-25 parts mixing water; wherein the target moisture content is controlled at 3%-8%.

[0193] In a preferred embodiment, to balance fluidity, stability and economy, the proportions are further preferably: 60-80 parts recycled fine aggregate, 12-20 parts cementitious material, 5-15 parts mineral admixture, 0.1-1.2 parts additive, and 10-20 parts mixing water, with a target moisture content of 4%-7%.

[0194] In a more preferred embodiment, a typical mix proportion suitable for general trench / foundation pit backfilling may be: 70-78 parts recycled fine aggregate, 14-18 parts cementitious material, 8-12 parts mineral admixture, 0.2-0.8 parts additive, and 12-18 parts mixing water, with a target moisture content of 5%-6.5%.

[0195] 3) Typical Formulation Examples (Examples 1 to 3): To facilitate the explanation of material composition and applicability, the following typical formulations are given:

[0196] Example 1 (General Backfill Type): 75 parts recycled fine aggregate; 16 parts cementitious material; 8 parts mineral admixture; 0.4 parts additive; 14 parts mixing water; target moisture content controlled at 5% to 6.5%.

[0197] This formula balances fluidity and stability, making it suitable for backfilling conventional trenches and foundation pits.

[0198] Example 2 (High-flow pumpable type): 68 parts recycled fine aggregate; 18 parts cementitious material; 12 parts mineral admixture; 0.8 parts additive; 18 parts mixing water; target moisture content controlled at 5% to 7%.

[0199] This formula increases the ratio of admixtures to additives, reduces the risk of bleeding, and improves pumping stability, making it suitable for long-distance transport or injection in confined spaces.

[0200] Example 3 (Economical Low-Cementation Type): 82 parts recycled fine aggregate; 12 parts cementitious material; 5 parts mineral admixture; 0.2 parts additive; 10 parts mixing water; target moisture content controlled at 4%–6%.

[0201] This formula uses a relatively low amount of cementitious material, making it suitable for scenarios where early strength requirements are not high and filling and self-compacting are the main functions.

[0202] 4) Target moisture content control and mixing matching relationship: In this embodiment, the target moisture content control of 3% to 8% is not simply achieved by adding water during mixing. Instead, the moisture content of the recycled fine aggregate is pre-converged to 3% to 8% through the main drying and closed-loop control method of Example 2 or 3, thereby forming a stable "controllable water window" during the material preparation stage. 8 to 25 parts of mixing water are added during the mixing stage under the action of the metering water addition device, and can be finely adjusted in combination with the dosage of admixtures (especially water-reducing agents / plasticizers) so that the material can meet the fluidity requirements while avoiding bleeding and segregation caused by excessive free water, thereby improving the mixing uniformity and engineering applicability of the fluidized solidified soil.

[0203] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An apparatus for producing fluidified solidified soil using construction waste, characterized by, The application relates to a device for preparing flow-state solidified soil from construction waste. The device comprises a pretreatment module for crushing, selecting and screening the construction waste, and only retaining mortar particles, concrete fine aggregates and brick powder; a pre-dewatering module for pre-dewatering the material output by the pretreatment module, so that the moisture content of the output material is controlled to be less than or equal to 14%; a main drying system (1), an auxiliary material adding device (2), a water adding device (3) and a mixing device; the mixing device is used for mixing the material processed by the main drying system (1), the auxiliary material added by the auxiliary material adding device (2) and the mixing water added by the water adding device (3). The main drying system (1) comprises a high-temperature drying area (11), a high-temperature buffer area (12) and a heat preservation discharging area (13) arranged in the vertical direction; the material processed by the pre-dewatering module is lifted to the high-temperature drying area (11) by a lifting device; the high-temperature drying area (11), the high-temperature buffer area (12) and the heat preservation discharging area (13) each comprise at least two groups of material conveying belts (14); a plurality of hot air outlets (15) are uniformly arranged at the top of the high-temperature drying area (11); the plurality of hot air outlets (15) are communicated through a hot air pipe; the inlet of the hot air pipe is communicated with a gas cavity heated by a heat source. One side of the main drying system (1) is provided with a recovery channel (16) communicated with the bottom of the heat preservation discharging area (13); the recovery channel (16) is provided with a dust baffle (17) arranged obliquely; the top of the recovery channel (16) is communicated with a heat exchange device; the air heated by the heat exchange device is delivered to a waste heat recovery pipe; the waste heat recovery pipe is communicated with a plurality of waste heat outlets facing the material conveying belts (14). The dust baffle (17) extends obliquely downward from the side wall of the recovery channel (16) to the middle; one group of dust baffles (17) is arranged on the two sides of the inner wall of the recovery channel (16); the dust baffles (17) on the two sides are arranged alternately.

3. The device for preparing flow-state solidified soil from construction waste according to claim 1, further comprising a main controller.

2. The apparatus for preparing fluidified solidified soil using construction waste according to claim 1, wherein The material conveying belts (14) are provided with microwave humidity sensors for obtaining the humidity of the material on the material conveying belts (14) and sending the humidity to the main controller. The high-temperature drying area (11), the high-temperature buffer area (12) and the heat preservation discharging area (13) are each provided with a temperature and humidity sensor for detecting the environmental temperature and humidity in the area and sending the temperature and humidity to the main controller. The main controller controls the speed of the material conveying belts (14), the opening degree of the valves of the hot air pipe and the waste heat recovery pipe according to the humidity of the material, the environmental temperature and humidity. The main controller comprises a data acquisition unit, a control calculation unit and an execution control unit; the data acquisition unit is used for filtering, calibrating and fusing the signals of the microwave humidity sensors and the temperature and humidity sensors; the execution control unit is connected with the frequency converter drives of the material conveying belts (14), the electric actuators of the valves of the hot air pipe and the electric actuators of the valves of the waste heat recovery pipe, so as to realize the closed-loop adjustment of the speed of the material conveying belts (14) and the opening degrees of the valves. ​ ​ 4. The apparatus for preparing fluidified solidified soil using construction waste according to claim 3, wherein ​ 5. The apparatus for preparing fluidified solidified soil using construction waste according to claim 4, wherein The main controller is configured to adopt a "material moisture content outer ring-zone temperature and humidity inner ring" cascade control logic: the target moisture content of the material on the material conveying belt (14) is used as the outer ring set value, and the outer ring output is used to correct the control amount of the material conveying belt (14) speed and the hot air pipe valve opening; the zone temperature and zone humidity set values of the inner ring are respectively used to coordinate and distribute the hot air supply and waste heat supply of the high-temperature drying zone (11), the high-temperature buffer zone (12) and the heat preservation discharge zone (13), so that the high-temperature drying zone (11) gives priority to meeting the evaporation driving force, the high-temperature buffer zone (12) is used to inhibit local overdrying and dust raising, and the heat preservation discharge zone (13) is used to stabilize the moisture content fluctuation of the discharge.

6. A method for producing a fluidified solidified soil using construction waste, characterized by, The device of any one of claims 1-5, comprising the following specific steps: S1, pretreatment: crushing, selecting and screening the construction waste, and only retaining mortar particles, concrete fine aggregates and brick powder to obtain pretreated materials; S2, pre-dewatering: pre-dewatering the pretreated materials to make the pre-dewatering discharge moisture content ≤14%; S3, main drying: lifting the pre-dewatered materials to the high-temperature drying zone of the main drying system through the lifting device, and making the materials pass through the high-temperature drying zone, the high-temperature buffer zone and the heat preservation discharge zone arranged in the vertical direction in sequence to complete drying; at least two groups of material conveying belts are used to convey the materials in the high-temperature drying zone, the high-temperature buffer zone and the heat preservation discharge zone; hot air is sent into a plurality of hot air ports uniformly arranged at the top of the high-temperature drying zone, and the plurality of hot air ports are communicated through hot air pipes, and the inlet of the hot air pipe is communicated with the air cavity heated by the heat source; S4, waste heat recovery and reuse: introducing the hot and humid air from the heat preservation discharge zone close to the bottom into the recovery channel, and making the hot and humid air form heated air after heat exchange in the heat exchange device, and the heated air is conveyed to the waste heat recovery pipe, and sprayed out from a plurality of waste heat ports of the waste heat recovery pipe to participate in drying and heat preservation; S5, mixing: sending the main dried materials, the auxiliary materials added by the auxiliary material adding device and the mixing water added by the water adding device into the mixing device to mix, and obtaining the flow solidified soil; S6, closed loop control: in the process of steps S3-S5, the moisture content of the material on the material conveying belt is collected by the microwave moisture sensor with a control period of 0.5-5s and the environmental temperature obtained by the temperature and humidity sensors in the high-temperature drying zone, the high-temperature buffer zone, and the heat preservation discharge zone and the relative humidity and a cascade closed loop control algorithm of "moisture content of material outer ring-area temperature and humidity inner ring" is executed. The outer loop is constructed with a target moisture content of 3% to 8% The moisture content error is calculated The outer loop control amount is calculated, and the material conveying belt speed set value is set according to the outer loop control amount The hot air pipe valve opening set value is corrected Wherein The amplitude is limited to 0.05 to 2.00 m / s The amplitude is limited to 10% to 100% The inner ring respectively regulates the temperature and humidity of each area in closed loop, so that the temperature of high-temperature drying area is set to 110-180℃, the relative humidity is set to 5%-25%, the temperature of high-temperature buffer area is set to 70-120℃, the relative humidity is set to 15%-45%, the temperature of heat preservation discharge area is set to 40-80℃, and the relative humidity is set to 25%-60%, and the valve opening degree of waste heat recovery pipe is coordinated and distributed accordingly , so that the amplitude is limited in the range of 0%-100%. Thus, through closed-loop adjustment of the material conveying belt speed, the hot air pipe valve opening and the waste heat recovery pipe valve opening, the discharge moisture content is stably converged to the target moisture content range.

7. The method according to claim 6, wherein the method is characterized by, In step S4, the hot and humid air in the recovery channel is made to form at least two times of turning and produce sedimentation separation along the inclined flow guide dust separation structures arranged alternately on both sides of the recovery channel, so as to inhibit the dust from entering the heat exchange device again after being entrained.

8. The method of claim 6, wherein the method further comprises: The filtering, calibration and fusion of the sensor signals in step S6 include at least one of the following: first-order low-pass or moving average filtering is used for moisture content, temperature and humidity signals, and the filtering window is 5-60 sampling points; "mutation rate threshold + 3σ outlier rejection" is used to reject abnormal points; ​ When more than 2 microwave humidity sensors are arranged at the same position, the moisture content is obtained by weight fusion, and the weight is updated adaptively according to the self-diagnosis state and historical variance; a linear calibration model is adopted The moisture content is calibrated and the coefficient It is updated once every 8-24 hours based on the control sample.

9. The method for preparing a fluidified solidified soil from construction waste according to any one of claims 6 to 8, characterized in that, The steady state criterion is set in step S6 as The material conveying belt speed fluctuation is limited to ≤±5% and the hot air pipe valve opening and waste heat recovery pipe valve opening fluctuation is limited to ≤±5% to stabilize the outfeed moisture content fluctuation after the steady state criterion is met for 60-300 s.

10. A fluidified solidified soil prepared using construction waste, characterized by, According to mass parts, comprising: The recycled fine aggregate 50-85 parts prepared by the method of claim 6; Cementitious material 10-25 parts; Mineral admixture 3-20 parts; Admixture 0.05-2.0 parts, mixing water 8-25 parts; The target moisture content is controlled at 3%-8%.

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