Anti-caking control method and system for hot reclamation of foundry spent sand

Abstract

The application discloses a kind of casting waste sand thermal regeneration anti-caking control method and system, it is related to foundry technology field, the application is by constructing a set of real-time feedback and the closed-loop control system of multiple technology cooperation, accurate control to anti-caking process is realized, effectively inhibit the sand grain melting and bonding caused by local overheating in regeneration process, improve the particle uniformity and overall quality of final regenerated sand, ensure that its performance meets the requirements of subsequent casting production, the application combines multiple technical means such as multistage temperature gradient control, inert gas fluidization, bio-based anti-caking agent addition and infrared real-time monitoring, through the linkage control of data stream driving, each technical link is mutually enhanced, and a synergistic gain effect is generated.This targeted precision intervention avoids the global over-treatment of traditional methods, reduces the consumption of thermal energy and anti-caking agent, and improves resource utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and specifically to a method and system for preventing agglomeration in the thermal regeneration of foundry waste sand. Background Technology

[0002] Casting is one of the fundamental processes of modern industry, and the sand used in casting molds, namely foundry sand, is a major consumable in the production process. To reduce production costs and industrial solid waste emissions, the recycling and regeneration of used foundry waste sand has become a crucial aspect of the foundry industry. Thermal regeneration is a widely used and highly effective regeneration technology. Its basic principle is to remove residual binders, coatings, and other organic matter from the surface of waste sand particles through high-temperature roasting, thereby restoring its usability.

[0003] Currently, common techniques used in the thermal regeneration of foundry waste sand include mechanical stirring, airflow disturbance, and the addition of chemical anti-caking agents. For example, in regeneration equipment such as rotary kilns or fluidized beds, the mechanical movement of the equipment or the introduction of gas is used to keep the sand particles in motion, thereby reducing static contact between them. Simultaneously, before or during heating, a certain amount of calcium carbonate powder or other inorganic salts are mixed into the waste sand as an anti-caking agent to raise the melting temperature of the low-melting-point eutectic in the waste sand system.

[0004] However, existing technologies have significant drawbacks. While simple mechanical or airflow disturbances can achieve some physical dispersion, they are energy-intensive and prone to equipment wear. Furthermore, their effectiveness in suppressing sand particle surface melting and adhesion caused by localized overheating is limited. Adding chemical anti-caking agents can result in uneven application, affecting the subsequent performance of the recycled sand and potentially causing environmental pollution. In addition, these methods are mostly open-loop controls, lacking real-time sensing and feedback adjustment of sand bed temperature changes during regeneration, and cannot specifically address localized areas prone to agglomeration, thus reducing the overall effectiveness of anti-caking measures. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for preventing agglomeration in the thermal regeneration of foundry waste sand. By using real-time temperature monitoring feedback and multi-technology collaborative regulation, it is possible to accurately suppress agglomeration, improve the quality of regenerated sand and the system operating efficiency, and solve the problems existing in the background technology.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The first aspect of the present invention provides a method for preventing agglomeration control of thermal regeneration of foundry waste sand, comprising the following steps: Step 1: Obtain foundry waste sand and pre-treat the foundry waste sand to generate pre-treated waste sand.

[0007] Step 2: Place the pretreated waste sand in a thermal regeneration device and heat the pretreated waste sand using a multi-stage temperature gradient control curve to generate heated waste sand.

[0008] Step 3: Inert gas flow is introduced into the heated waste sand and a bio-based anti-caking agent is added simultaneously to generate fluidized waste sand.

[0009] Step 4: Monitor the temperature of the fluidized waste sand in real time and generate temperature distribution data.

[0010] Step 5: Analyze the temperature distribution data to determine if there are local hot spots, and generate dynamic adjustment parameters for regulating the inert airflow rate and the amount of bio-based anti-caking agent added.

[0011] Step 6: Apply dynamic adjustment parameters to control the processing of the thermal regeneration equipment until the fluidized waste sand is converted into regenerated sand.

[0012] Step 7: Cool the recycled sand to obtain the final recycled sand.

[0013] A second aspect of the present invention provides a system for implementing the anti-caking control method for thermal regeneration of foundry waste sand as described in the present invention, comprising: a pretreatment module for treating foundry waste sand to generate pretreated waste sand.

[0014] The thermal regeneration module, connected to the pretreatment module, includes a temperature control unit, an airflow addition unit, and an infrared monitoring unit, and is used to convert pretreated waste sand into regenerated sand.

[0015] The cooling module, connected to the thermal regeneration module, is used to convert the regenerated sand into the final regenerated sand.

[0016] The infrared monitoring unit is configured to generate temperature distribution data, and the temperature distribution data is used to control the flow rate of the inert airflow and the amount of bio-based anti-caking agent added in the airflow addition unit.

[0017] The beneficial effects of this invention are as follows: By constructing a closed-loop control system that integrates real-time feedback and multi-technology collaboration, this invention achieves precise control over the anti-caking process, effectively suppresses sand particle melting and adhesion caused by local overheating during the regeneration process, improves the particle uniformity and overall quality of the final regenerated sand, and ensures that its performance meets the requirements of subsequent casting production.

[0018] This invention organically combines multiple technologies, including multi-stage temperature gradient control, inert airflow fluidization, bio-based anti-caking agent addition, and real-time infrared monitoring. Through data-driven, interconnected control, each technological element enhances the others, resulting in a synergistic effect. This targeted intervention avoids the global over-processing of traditional methods, reduces the consumption costs of thermal energy and anti-caking agents, and improves the resource utilization efficiency of the entire regeneration process.

[0019] This invention introduces intelligent, adaptive control logic, enabling the regeneration system to dynamically adjust operating parameters based on real-time conditions, enhancing process stability and adaptability to waste sand from different sources. Simultaneously, by employing environmentally friendly bio-based anti-caking agents, it avoids secondary pollution problems that may arise from conventional chemical additives, making the entire regeneration process greener and more environmentally friendly, meeting the requirements of modern industrial sustainable development. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the implementation steps of the method of the present invention.

[0022] Figure 2 This is a schematic diagram of the system module connections of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Reference Figure 1 As shown, the first aspect of the present invention provides a method for preventing agglomeration of foundry waste sand by thermal regeneration, comprising the following steps: Step 1: Obtain foundry waste sand and pre-treat the foundry waste sand to generate pre-treated waste sand.

[0025] In a specific embodiment of the present invention, in step 1, the pretreatment of foundry waste sand to generate pretreated waste sand includes: Step 1.1: crushing foundry waste sand to generate crushed waste sand.

[0026] Specifically, foundry waste sand is fed into crushing equipment to crush larger sand lumps, adhered core sand clumps, and other hard aggregates formed during the casting and cooling processes. The purpose of this operation is to reduce the overall particle size of the waste sand, separate the bonded sand particles, thereby increasing the specific surface area of ​​the sand and facilitating subsequent heat transfer and impurity separation. After this operation, the material is transformed into crushed waste sand. The crushing equipment includes, for example, a jaw crusher or a hammer crusher.

[0027] Step 1.2: Perform magnetic separation and screening to remove impurities from the crushed waste sand, separating ferromagnetic impurities, non-sand impurities, and particles of unqualified size to generate pretreated waste sand.

[0028] Specifically, combining multiple physical separation methods, the process begins with a magnetic separator. A strong magnetic field, generated by a permanent magnet drum or electromagnet, adsorbs and separates ferromagnetic metallic impurities such as iron filings and riser residues from the crushed waste sand. Subsequently, the material enters a vibrating screen or air separator. By controlling the screen aperture or airflow velocity, particles that are too large or too small, as well as low-density dust and residual resin powder, are removed. After impurity removal, the resulting material is pre-treated waste sand with relatively pure composition and uniform particle size distribution. This pre-treated waste sand is a qualified raw material for the thermal regeneration equipment.

[0029] By performing the above pretreatment steps, not only are pretreated waste sands with uniform physical properties obtained, but the entire anti-caking control method also gains significant technical advantages. First, the uniform particle size ensures that heat can be evenly and rapidly transferred to each sand grain during the subsequent heating stage, effectively avoiding localized overheating caused by uneven heat transfer within the sand clumps. This is the physical basis for preventing surface melting and agglomeration of the sand grains. Second, the removal of metallic impurities and excessive dust improves the fluidization quality of the sand bed under inert airflow, ensuring sufficient contact and uniform mixing of the gas and solid phases. This provides stable operating conditions for the effective coating of the bio-based anti-caking agent and accurate temperature measurement by the infrared monitoring device. Therefore, this pretreatment step, as the starting point of the method, produces high-quality pretreated waste sand, laying a solid foundation for the synergistic effect of subsequent multi-stage temperature control, airflow fluidization, and closed-loop feedback control technologies. This reduces the tendency to agglomerate, improves the quality of the final recycled sand, and enhances the stability of the system operation.

[0030] Step 2: Place the pretreated waste sand in a thermal regeneration device and heat the pretreated waste sand using a multi-stage temperature gradient control curve to generate heated waste sand.

[0031] In a specific embodiment of the present invention, in step 2, the application of a multi-stage temperature gradient control curve to heat the pretreated waste sand includes: specifically, the step of applying a preset multi-stage temperature gradient curve to heat the pretreated waste sand entering the thermal regeneration equipment is a precise and controllable heat energy input process, which aims to orderly remove various residues on the surface of the waste sand and create suitable temperature conditions for subsequent anti-caking measures.

[0032] Step 2.1: Perform the first stage of slow heating treatment on the pretreated waste sand, with a heating rate of [missing information]. This generates pre-heated waste sand.

[0033] It should be noted that the core of the control in the above steps is to use a gradual heating rate, that is, the initial segment of the preset multi-stage temperature gradient curve, whose heating rate... Through formula Configure, among which The first phase aims to achieve a temperature rise. The slow heating process, which takes the required time, aims to smoothly remove residual moisture and low-boiling-point volatile organic compounds from the waste sand, avoiding sand particle breakage caused by the rapid expansion of water vapor or gas due to a sudden temperature rise. After this stage is completed, the material state is transformed into pre-heated waste sand.

[0034] Step 2.2: Perform a second-stage rapid heating treatment on the pre-heated waste sand, with a heating rate of [missing information]. This generates intermediate heating waste sand.

[0035] It should be noted that this stage corresponds to the rapid heating section in the temperature gradient curve, and its heating rate... The temperature rises significantly higher than in the first stage, with the aim of raising the waste sand temperature to the range where the main organic binders, such as resins, can be efficiently thermally decomposed in the shortest possible time. To prevent localized overheating during this rapid heating process, equipment rotation or airflow disturbance is usually employed to ensure uniform heat distribution. After this stage, the material is transformed into intermediate-heated waste sand.

[0036] Step 2.3: Perform a third-stage heat preservation treatment on the intermediate heating waste sand to generate heated waste sand.

[0037] It should be noted that this stage is a high-temperature holding or slight heating stage, and the heating rate... The purpose is to maintain a stable high temperature sufficient to burn off residual charcoal for a period of time, ensuring the waste sand surface is thoroughly cleaned. After this heat preservation process is completed, the waste sand as a whole reaches and is maintained at the ideal regeneration temperature, and its state is that of heated waste sand, which prepares it for the next step of introducing inert airflow and anti-caking agent.

[0038] The application of this multi-stage temperature gradient control method produces technical effects different from simple heating treatment. First, the staged heating strategy achieves selective and orderly removal of different waste sand components, ensuring regeneration efficiency while protecting the physical integrity of the sand particles through initial gentle heating, thus improving the recovery rate and performance of the regenerated sand. Second, this refined temperature control is the foundation for the synergistic effect of the entire invention. The first-stage preheating provides a stable material basis for subsequent processes. The rapid heating in the second stage quickly brings the waste sand into the optimal activation temperature window of the bio-based anti-caking agent. The third-stage isothermal control provides a stable operating environment for the full interaction between the anti-caking agent and the sand particle surface, as well as for the precise feedback control of the infrared real-time monitoring system. Therefore, this step is not merely a simple heating process, but a crucial link connecting the preceding and following stages. Through pre-programmed control, it precisely matches the changes in the temperature field with subsequent physical and chemical anti-caking methods in time and space, laying a decisive thermodynamic foundation for ultimately achieving the goal of efficient and low-energy anti-caking control.

[0039] Step 3: Inert gas flow is introduced into the heated waste sand and a bio-based anti-caking agent is added simultaneously to generate fluidized waste sand.

[0040] In a specific embodiment of the present invention, in step 3, the step of introducing an inert gas flow into the heated waste sand and simultaneously adding a bio-based anti-caking agent includes: specifically, this step is a key step in implementing active anti-caking intervention after the heated waste sand reaches a predetermined regeneration temperature.

[0041] Step 3.1: Inert gas flow is introduced into the heated waste sand to form a fluidized state, generating waste sand covered by the gas flow.

[0042] Specifically, an inert gas flow, such as nitrogen or argon, is introduced into the heated waste sand bed at a preset flow rate through a gas distributor located at the bottom of the thermal regeneration equipment.

[0043] It should be noted that the inert gas flow has a dual function: firstly, it creates an oxygen-free or oxygen-deficient environment, preventing unintended oxidation reactions of residual carbon and metal elements on the surface of the sand particles at high temperatures; secondly, when the flow rate of the inert gas flow reaches a level that causes the apparent gas velocity to exceed the minimum fluidization velocity of the sand particles... At this point, the upward drag force of the gas on the sand particles is sufficient to overcome the gravity of the sand particles, causing the entire sand bed to expand and exhibit a boiling-like state similar to that of a liquid; this is the phenomenon of fluidization. Minimum fluidization velocity. It is an inherent property of the material, depending on the particle size and density of the sand particles and the properties of the gas. In this fluidized state, the sand particles are surrounded by a gas film and are in continuous random motion, forming waste sand covered by airflow.

[0044] Step 3.2: Add a bio-based anti-caking agent to the waste sand covered by the airflow, and use the fluidization state to uniformly disperse the bio-based anti-caking agent to generate fluidized waste sand.

[0045] Specifically, a pre-set powdered bio-based anti-caking agent is precisely injected into the waste sand covered by the formed airflow through an independent conveying system, such as a screw feeder or pneumatic conveying device.

[0046] It should be noted that, because the sand bed is already in a state of intense fluidization, the injected powdered bio-based anti-caking agent will be rapidly and evenly dispersed by the powerful gas-solid mixing action and adhere to the surface of each moving sand grain. After this process is completed, the material is transformed into fluidized waste sand, characterized by sand grains suspended and moving under the support of inert gas, with a uniform layer of anti-caking agent coating on the surface.

[0047] The combined effect of this process surpasses that of simply introducing gas or adding individual additives. The introduction of an inert gas flow firstly, through fluidization, physically forces the separation of high-temperature sand particles, reducing the probability of sintering due to contact – a dynamic mechanical isolation. Secondly, this fluidized state creates a carrier and dispersion environment for the addition of bio-based anti-caking agents. Without fluidization, additives are difficult to mix uniformly, reducing their effectiveness. Under this synergistic effect, the inert gas flow acts not only as a fluidization medium but also as a highly efficient transport and dispersion medium for the anti-caking agent. The anti-caking agent, uniformly coated on the surface of the sand particles, forms a stable physical isolation layer at high temperatures, preventing the adhesion of molten material on the sand particle surface from both chemical and materials science perspectives. Therefore, this step, through the dual mechanisms of physical fluidization and surface modification, constructs a three-dimensional, dynamic anti-caking barrier, resulting not only in superior anti-caking effects but also ensuring that every additive is effective, creating a uniform and controllable treatment environment for subsequent real-time monitoring and fine-tuning.

[0048] Step 4: Monitor the temperature of the fluidized waste sand in real time and generate temperature distribution data.

[0049] In a specific embodiment of the present invention, in step 4, the real-time monitoring of the temperature of the fluidized waste sand includes: step 4.1: scanning the surface of the fluidized waste sand by an infrared monitoring device installed on the inner wall of the thermal regeneration equipment that can overlook the entire fluidized waste sand bed to obtain raw temperature data.

[0050] Specifically, the surface of the sand bed is continuously scanned by an infrared monitoring device. The infrared monitoring device captures the infrared radiation emitted by the high-temperature sand particles in a non-contact manner and converts it into the corresponding temperature value according to Planck's radiation law. Each scan generates a thermal image containing several pixels, where the gray value or color value of each pixel corresponds to a specific temperature reading. A series of unprocessed pixel-level temperature matrix sets collected in chronological order constitute the raw temperature data.

[0051] Step 4.2: Process and analyze the raw temperature data to generate temperature distribution data that includes the location and intensity of local hotspots.

[0052] Specifically, the data is first corrected by considering the emissivity of the waste sand material at the current temperature to improve temperature measurement accuracy. Then, digital image processing algorithms, such as Gaussian filtering or median filtering, are applied to remove isolated outliers caused by dust obstruction or sensor noise. Finally, statistical analysis algorithms are used to extract key feature parameters from the processed temperature matrix. These include calculating the average temperature of the entire sand bed, identifying and locating the hotspots (extreme temperature points), and calculating the variance or standard deviation of the temperature field to quantify temperature uniformity. The extracted and structured set of key parameters constitutes the temperature distribution data used for subsequent control decisions. This temperature distribution data can be represented as... in For temperature distribution data, The average temperature. The highest temperature, ( ( ) represents the coordinates of the highest temperature point within the sand bed. This represents the temperature standard deviation.

[0053] The introduction of this real-time monitoring and data processing step transforms traditional open-loop, experience-based operations into precise, closed-loop intelligent control. Through high-resolution real-time temperature monitoring, this method can detect localized temperature anomalies that traditional single-point temperature measurement methods cannot detect. This means that instead of passively responding to already formed agglomerates, it can provide early warnings and obtain precise location and severity information when agglomerates first appear, i.e., when local hotspots emerge. The generated temperature distribution data, especially the hotspot coordinates and temperature uniformity indicators, provides direct and quantitative decision-making basis for subsequent adjustment strategies, enabling targeted and on-demand allocation of inert airflow regulation and the replenishment of bio-based anti-caking agents. This control mode based on real-time, precise feedback improves the targeting and efficiency of anti-caking measures, avoids excessive global intervention, and thus reduces energy and material consumption while ensuring anti-caking effectiveness. It serves as the perception and decision-making center for achieving synergistic efficiency across the entire system.

[0054] Step 5: Analyze the temperature distribution data to determine if there are local hot spots, and generate dynamic adjustment parameters for regulating the inert airflow rate and the amount of bio-based anti-caking agent added.

[0055] In a specific embodiment of the present invention, step 5 specifically includes: Specifically, this step is the decision-making and calculation center of the entire closed-loop control system, and its core task is to transform the temperature distribution data characterizing the state of the sand bed obtained in the previous step into specific, executable control commands.

[0056] Step 5.1: Extract the highest temperature of local hotspots from the temperature distribution data. Temperature threshold for characterizing the risk of agglomeration A comparison is made to generate a temperature deviation signal, which includes not only the deviation value, but also... It also includes the coordinates of the location of the highest temperature point in the sand bed. This forms a composite signal containing both intensity and location information.

[0057] It should be noted that when , Forced to be set to 0.

[0058] The temperature threshold that characterizes the risk of agglomeration is a safe upper limit determined in advance through experiments or simulations based on process parameters such as waste sand type and binder residue characteristics.

[0059] Step 5.2: Based on the intensity of the temperature deviation signal and the location of local hot spots, calculate the increment of the inert airflow rate and the increment of the bio-based anti-caking agent addition rate to generate dynamic adjustment parameters.

[0060] The increment of the inert airflow rate Increment of the addition rate of bio-based anti-caking agents The calculations are performed using the following proportional control relationships. and ,in and These are the pre-tuned flow rate and dosage proportional gain coefficients, used to adjust the intensity of the control response. The calculated increments in the inert airflow rate and the bio-based anti-caking agent addition rate together constitute the adjusted processing parameters, which are sent as output commands to the actuator, such as... , =0.2(kg / min) / .

[0061] The technical effect of this decision-making and calculation step is to achieve an intelligent link from perception to response, which is the key to the entire method's proactive and precise anti-caking control. By converting temperature data into specific temperature deviation signals, this step provides the control system with a clear and quantitative basis for judgment, enabling accurate assessment of the severity of the caking risk. Secondly, proportional calculations based on this signal ensure that subsequent adjustment measures are appropriate and on-demand, rather than excessive intervention in a one-size-fits-all manner. When local overheating is slight, the adjustment amount is also small, avoiding unnecessary waste of energy and materials. When overheating is severe, the adjustment amount is increased accordingly, ensuring the effectiveness of the intervention measures. This dynamic calculation based on deviation signals transforms anti-caking control from a static, preset program into a dynamic equilibrium process that can self-adjust according to real-time operating conditions. It ensures that subsequent physical cooling (enhanced airflow) and chemical isolation (supplementary additives) can accurately act on the root cause of the problem, thereby bringing the system state back to a safe range with high efficiency and low cost. This is a key logical link in achieving synergistic efficiency and resource optimization of the overall method.

[0062] Step 6: Apply dynamic adjustment parameters to control the processing of the thermal regeneration equipment until the fluidized waste sand is converted into regenerated sand.

[0063] In a specific embodiment of the present invention, in step 6, the process of applying dynamic adjustment parameters to control the thermal regeneration equipment includes: specifically, this step is the execution terminal of the closed-loop control loop, responsible for materializing the adjusted processing parameters generated in the previous step into actual regulation of the physicochemical environment within the thermal regeneration equipment.

[0064] Step 6.1: Adjust the flow rate of the inert airflow and the addition rate of the bio-based anti-caking agent according to the dynamic adjustment parameters to generate an optimized treatment environment.

[0065] Specifically, the dynamic adjustment parameters are transmitted to the actuators of the inert airflow supply system and the bio-based anti-caking agent addition system, respectively. For the airflow supply system, the actuators, such as variable frequency fans or electric regulating valves, respond to the commands. Accordingly, increase the fan speed or open the valve wider to increase the total airflow rate into the sand bed. ,in To adjust the flow rate of the inertial airflow before adjustment, for additive systems, actuators such as variable frequency screw feeders operate according to instructions. Increasing its operating frequency increases the rate at which the anti-caking agent is added. ,in The original addition rate of the bio-based anti-caking agent was shown. The real-time changes to the above operating conditions collectively created a dynamically optimized treatment environment to address localized overheating.

[0066] It should be noted that, in the specific implementation process, the dynamic adjustment parameters are also subject to boundary conditions. For example, the upper limit of the increment of the inert airflow rate is 5 m³ / h, and the upper limit of the increment of the bio-based anti-caking agent addition rate is 0.5 kg / min; when the calculated increment of the single inert airflow rate exceeds 5 m³ / h, it is taken as... When the calculation yields a single result When the flow rate exceeds 0.5 kg / min, take... Meanwhile, the total flow rate of the inert airflow shall not exceed 2.5 times the maximum fluidization flow rate of the sand bed, and the total amount of bio-based anti-caking agent added shall not exceed 0.5% of the mass of foundry waste sand, so as to avoid excessive fluidization or excessive additives affecting the performance of recycled sand.

[0067] Step 6.2: Continue processing the fluidized waste sand under optimized processing environment until the temperature distribution data returns to a uniform state, generating recycled sand.

[0068] Specifically, the enhanced inertial airflow will more forcefully agitate the sand particles, especially in previously detected hotspot areas. Nearby, the hotspot areas, due to their higher temperatures, experience more intense sand particle movement, creating a stronger demand for localized airflow disturbance. The enhanced global airflow naturally concentrates in these hotspot areas where sand particle disturbance is more intense and airflow resistance is relatively lower. The added bio-based anti-caking agent is preferentially transported by the enhanced airflow and coats the surface of these hottest sand particles, forming a more effective isolation layer. The entire heating process continues under this optimized treatment environment, achieving the enrichment and distribution of the bio-based anti-caking agent towards the localized hotspot areas along with the enhanced inert airflow, until all waste sand meets the recycling standards. The product at this point is recycled sand.

[0069] The technical effect of this execution and continuous processing step is the ultimate realization of closed-loop control, transforming the results of data analysis and decision calculations into direct intervention in the process, thereby producing a synergistic suppression of agglomeration effects. When enhanced airflow and supplementary additives act simultaneously on hot spots, the effect is far superior to the simple sum of their individual effects. Enhanced airflow not only removes heat but also promotes the rapid and uniform dispersion and adhesion of new additives, improving the efficiency of chemical isolation. The endothermic decomposition reaction that the additives may undergo at high temperatures, in turn, assists in the local cooling effect of the airflow. This immediate linkage and mutual reinforcement between physical cooling and chemical isolation forms a highly efficient targeted treatment mechanism, rapidly suppressing the tendency of sand particles to melt and agglomerate in local hot spots. By completing the remaining regeneration process in a dynamically established optimized treatment environment, this method ensures that the sand bed temperature remains within a uniform and controllable safe range throughout the entire treatment cycle, preventing the formation of large-scale agglomeration.

[0070] Step 7: Cool the recycled sand to obtain the final recycled sand.

[0071] In a specific embodiment of the present invention, step 7, the cooling treatment of the recycled sand includes: specifically, this cooling treatment step is the final step of the entire recycling process, and its key is to quickly and uniformly reduce the recycled sand that has been regenerated at a high temperature to room temperature, so as to solidify its excellent particle state and prepare it for subsequent use.

[0072] Step 7.1: Transfer the recycled sand from the thermal recycling equipment to the cooling device through a transfer mechanism such as a discharge valve or conveyor belt to generate recycled sand under cooling.

[0073] The cooling device is a high-efficiency heat exchanger such as a fluidized bed cooler, a water-cooled screw conveyor, or a drum cooler.

[0074] Step 7.2: Force-cool the regenerated sand during cooling until its temperature drops to a safe range for processing, thus generating the final regenerated sand.

[0075] Taking a fluidized bed cooler as an example, a large amount of ambient or low-temperature air is introduced into the bottom of the sand bed, causing the high-temperature sand particles to re-fluidize and dissipate heat through intense convection between the gas and solid. This method has a much higher heat exchange efficiency than natural cooling. The entire cooling process is precisely controlled, ensuring that the forced cooling process terminates when the overall temperature of the sand particles drops to a safe standard. The result is final recycled sand with stable physical properties, which can be directly packaged or sent to the next process.

[0076] For example, the endpoint temperature of forced cooling is ≤80°C, which is the critical temperature for safe handling, storage and reuse of recycled foundry waste sand. This avoids secondary agglomeration and clumping of high-temperature recycled sand and minimizes cooling energy consumption.

[0077] This cooling process, especially the application of forced cooling, plays a crucial technical role in ensuring the quality of the final recycled sand and improving overall process efficiency. Firstly, rapid and uniform cooling effectively suppresses secondary agglomeration or clumping of the recycled sand after high-temperature unloading. This is because the surface of sand particles at high temperatures still retains some activity, and slow cooling increases the risk of them contacting and sticking together. Forced cooling quickly removes the sand particles from the danger zone, solidifying the single-particle dispersion obtained during the thermal regeneration stage. Secondly, the efficient cooling method shortens the cycle time of the entire regeneration process, avoiding the large storage areas and long waiting times required for natural cooling, thereby improving the overall processing capacity and economic efficiency of the production line. Finally, the controlled cooling rate helps prevent sand particles from cracking due to thermal stress caused by rapid temperature differences, ensuring that the final recycled sand has excellent particle size distribution and mechanical strength, enabling it to directly meet the stringent requirements of subsequent casting production.

[0078] In a specific embodiment of the present invention, the bio-based anti-caking agent is composed of biodegradable starch and natural silicate. Its addition amount and the flow rate of the inert gas flow are linked through the dynamic adjustment parameters to achieve a synergistic anti-caking effect of physical dispersion and chemical isolation.

[0079] It should be noted that the biodegradable starch is an organic polymer material that undergoes pyrolysis under the high-temperature environment of thermal regeneration, generating a porous carbonaceous layer; this process is itself an endothermic reaction. The other key component, natural silicate, such as montmorillonite or kaolin, is an inorganic refractory material with a melting point much higher than the sintering temperature of foundry sand. During preparation, micron-sized natural silicate particles are uniformly attached to or embedded into the starch particle matrix through methods such as spray drying or mechanical blending, forming composite particles. This structural design ensures that both components can simultaneously reach the surface of the sand particles during application.

[0080] Specifically, when the infrared monitoring device detects a local temperature deviation signal At the same time, the control algorithm will not only calculate the increment of the anti-caking agent addition amount It will also calculate the increment of the inertial airflow. And maintaining a specific dynamic ratio between the two means that when stronger chemical isolation is required, stronger physical dispersion and cooling capabilities must be matched.

[0081] The combination of this specific component and dynamic linkage mechanism produces a synergistic anti-caking effect, with an overall effect far exceeding the sum of the individual components. First, it constructs a multi-layered, three-dimensional anti-caking barrier. At high temperatures, the carbon layer formed by starch pyrolysis provides initial physical isolation and absorbs heat, while the more stable natural silicate particles constitute a second, robust refractory isolation layer, effectively preventing the melting and bridging of silicates on the sand surface. Second, the linkage between the inert airflow and the anti-caking agent achieves a dual effect of precise guidance and enhancement. The increased airflow not only provides the incremental additive with the transport power and dispersion medium to reach the hot spot area, but its own enhanced convective cooling effect is also superimposed with the pyrolysis endothermic effect of the additive starch component, forming a localized cooling capability. This high degree of synchronization and mutual reinforcement between physical cooling and chemical isolation in time and space makes the suppression response to initial agglomeration more rapid and efficient. Therefore, this technical solution is not a simple patchwork of materials and processes, but rather an organic integration of two anti-caking methods through deep coupling of material design and control strategies, thereby improving the reliability, efficiency, and economy of anti-caking.

[0082] Reference Figure 2As shown, a second aspect of the present invention provides a system for implementing the anti-caking control method for thermal regeneration of foundry waste sand according to the present invention, comprising: a pretreatment module for treating foundry waste sand to generate pretreated waste sand.

[0083] The thermal regeneration module, connected to the pretreatment module, includes a temperature control unit, an airflow addition unit, and an infrared monitoring unit, and is used to convert pretreated waste sand into regenerated sand.

[0084] The cooling module, connected to the thermal regeneration module, is used to convert the regenerated sand into the final regenerated sand.

[0085] The infrared monitoring unit is configured to generate temperature distribution data, and the temperature distribution data is used to control the flow rate of the inert airflow and the amount of bio-based anti-caking agent added in the airflow addition unit.

[0086] The core principle of this invention lies in constructing a closed-loop collaborative control system based on real-time sensing and dynamic feedback to proactively prevent agglomeration of foundry waste sand during the thermal regeneration process. First, pretreated waste sand is programmed to be heated using a multi-stage temperature gradient curve, creating precise thermodynamic conditions for the orderly decomposition of different residues and the activation of the anti-agglomeration agent. Based on this, the physical dispersion effect provided by inert gas flow fluidization is organically combined with the surface chemical isolation effect provided by the bio-based anti-agglomeration agent, constructing a fundamental dual anti-agglomeration mechanism. More importantly, real-time infrared monitoring is introduced as a sensing element to continuously acquire temperature distribution data across the entire sand bed. This data is used as a decision-making basis; once a localized hot spot indicating a risk of agglomeration is identified, adjusted processing parameters are immediately generated. These parameters dynamically and in tandemly regulate the flow rate of the inert gas flow and the amount of bio-based anti-agglomeration agent added, precisely applying enhanced physical cooling and chemical inhibition capabilities to the problem area. Ultimately, the controlled cooling process solidifies the recycled sand into a superior state, thus forming a complete technical closed loop that integrates programmed presets, multi-mechanism collaboration, real-time sensing, and adaptive adjustment. This fundamentally transforms anti-caking control from a static, passive process measure into a dynamic, proactive, and intelligent process.

[0087] This invention, through the implementation of the aforementioned technical principles, achieves comprehensive technical effects that surpass existing single or simple combinations of techniques. First, the method improves the efficiency and reliability of anti-caking, enhancing the quality of the final recycled sand, resulting in uniform particles, no hard lumps, and highly stable performance, meeting the reuse requirements of high-end casting processes. Second, based on a real-time feedback-driven on-demand adjustment mechanism, energy and material consumption are precisely allocated to the necessary stages, effectively avoiding global overheating and excessive use of anti-caking agents, thus achieving energy conservation and consumption reduction. Furthermore, the automation and intelligence levels of the entire process are improved, giving the system greater robustness and the ability to adapt to fluctuations in the properties of different batches of waste sand, ensuring the stability and continuity of the production process. Finally, by employing a bio-based anti-caking agent, the potential secondary pollution problems caused by traditional chemical additives are avoided, making the entire foundry waste sand recycling process more environmentally friendly and in line with the industrial requirements of sustainable development. Overall, this method achieves synergistic improvements in product quality, production efficiency, resource utilization, and environmental protection across multiple dimensions.

[0088] It should be added that the formulas mentioned above, through the principle of dimensional consistency and mathematical standardization methods—such as normalization, dimensionless parameter conversion, or unit system unification—can translate physical quantities with different properties into unitless standard values ​​or superimposed parameters of the same dimension. This eliminates the interference of different dimensions on the computational logic, allowing the formulas to retain the original data distribution characteristics while possessing mathematical rationality and adaptability to objective laws. The above descriptions are merely exemplary embodiments of the present invention and should not be construed as limiting the scope of the invention.

[0089] It should also be noted that the various key threshold settings described in this invention, such as the temperature threshold characterizing the risk of agglomeration and the minimum fluidization velocity threshold for sand particles, are specifically determined based on a combination of the type of foundry waste sand, such as sand particle material and particle size distribution, and the residual characteristics of binder, such as resin type and residual amount, through extensive thermal regeneration experiments and process simulation analysis. Furthermore, the thresholds are dynamically calibrated by incorporating the experience and judgment of experts in the field regarding the balance between process stability, energy consumption, and regenerated sand quality. In addition, factors such as batch fluctuations in waste sand, differences in equipment heating power, and uniformity of airflow distribution in actual production are comprehensively considered. This approach has a solid scientific basis and practical operability, and the relevant threshold setting and calibration methods in the prior art are relatively mature, so they will not be elaborated upon here.

[0090] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0091] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0092] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0093] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, and all such modifications and additions should fall within the protection scope of the present invention.

Claims

1. A method for preventing agglomeration in the thermal regeneration of foundry waste sand, characterized in that, Includes the following steps: Step 1: Obtain foundry waste sand and pre-treat it to generate pre-treated waste sand; Step 2: Place the pretreated waste sand in a thermal regeneration device and heat the pretreated waste sand using a multi-stage temperature gradient control curve to generate heated waste sand; In step 2, the application of a multi-stage temperature gradient control curve to heat the pretreated waste sand includes: Step 2.1: Perform the first stage of slow heating treatment on the pretreated waste sand, with a heating rate of [missing information]. This generates pre-heated waste sand; Step 2.2: Perform a second-stage rapid heating treatment on the pre-heated waste sand, with a heating rate of [missing information]. This generates intermediate heating waste sand; Step 2.3: Perform a third-stage heat preservation treatment on the intermediate heating waste sand to generate the heating waste sand; Step 3: Inert gas flow is introduced into the heated waste sand and a bio-based anti-caking agent is added simultaneously to generate fluidized waste sand; Step 4: Monitor the temperature of the fluidized waste sand in real time and generate temperature distribution data; Step 5: Analyze the temperature distribution data to determine if there are local hot spots, and generate dynamic adjustment parameters for regulating the inert airflow rate and the amount of bio-based anti-caking agent added; The specific content of step 5 includes: Step 5.1: Extract the highest temperature of local hotspots from the temperature distribution data. Temperature threshold for characterizing the risk of agglomeration A comparison is made to generate a temperature deviation signal, which includes not only the deviation value, but also... It also includes the coordinates of the location of the highest temperature point in the sand bed. This constitutes a composite signal containing both intensity and location information; Step 5.2: Based on the intensity of the temperature deviation signal and the location of local hot spots, calculate the increment of the inert airflow rate and the increment of the bio-based anti-caking agent addition rate to generate dynamic adjustment parameters; The increment of the inert airflow rate Increment of the addition rate of bio-based anti-caking agents The calculations are performed using the following proportional control relationships. and ,in and These are the pre-tuned flow rate and the proportional gain coefficient of the added amount, used to adjust the intensity of the control response; Step 6: Apply dynamic adjustment parameters to control the processing of the thermal regeneration equipment until the fluidized waste sand is converted into regenerated sand; Step 7: Cool the recycled sand to obtain the final recycled sand.

2. The method for preventing agglomeration in the thermal regeneration of foundry waste sand according to claim 1, characterized in that, In step 1, the pretreatment of foundry waste sand to generate pretreated waste sand includes: Step 1.1: Crush the foundry waste sand to generate crushed waste sand; Step 1.2: Perform magnetic separation and screening to remove impurities from the crushed waste sand, separating ferromagnetic impurities, non-sand impurities, and particles of unqualified size to generate pretreated waste sand.

3. The method for preventing agglomeration in the thermal regeneration of foundry waste sand according to claim 1, characterized in that, In step 3, the process of introducing an inert gas stream into the heated waste sand and simultaneously adding a bio-based anti-caking agent includes: Step 3.1: Inert gas flow is introduced into the heated waste sand to form a fluidized state, generating waste sand covered by the gas flow; Step 3.2: Add a bio-based anti-caking agent to the waste sand covered by the airflow, and use the fluidization state to uniformly disperse the bio-based anti-caking agent to generate fluidized waste sand.

4. The method for preventing agglomeration in the thermal regeneration of foundry waste sand according to claim 1, characterized in that, In step 4, the real-time monitoring of the temperature of the fluidized waste sand includes: Step 4.1: Scan the surface of the fluidized waste sand using an infrared monitoring device to obtain raw temperature data; Step 4.2: Process and analyze the raw temperature data to generate temperature distribution data that includes the location and intensity of local hotspots.

5. The method for preventing agglomeration in the thermal regeneration of foundry waste sand according to claim 1, characterized in that, In step 6, the process of applying dynamically adjusted parameters to control the thermal regeneration equipment includes: Step 6.1: Adjust the flow rate of the inert airflow and the addition rate of the bio-based anti-caking agent according to the dynamic adjustment parameters to generate an optimized treatment environment; Step 6.2: Continue processing the fluidized waste sand under optimized processing environment until the temperature distribution data returns to a uniform state, generating recycled sand.

6. The method for preventing agglomeration in the thermal regeneration of foundry waste sand according to claim 1, characterized in that, In step 7, the cooling treatment of the recycled sand includes: Step 7.1: Transfer the recycled sand from the thermal recycling equipment to the cooling device to generate recycled sand under cooling; Step 7.2: Force-cool the regenerated sand during cooling until its temperature drops to a safe range for processing, thus generating the final regenerated sand.

7. The method for preventing agglomeration in the thermal regeneration of foundry waste sand according to claim 3, characterized in that, The bio-based anti-caking agent is composed of biodegradable starch and natural silicate. Its addition amount and the flow rate of the inert gas flow are linked through the dynamic adjustment parameters to achieve a synergistic anti-caking effect of physical dispersion and chemical isolation.

8. A system for implementing the anti-caking control method for thermal regeneration of foundry waste sand according to any one of claims 1-7, characterized in that, include: The pretreatment module is used to process foundry waste sand to generate pretreated waste sand; The thermal regeneration module, connected to the pretreatment module, includes a temperature control unit, an airflow addition unit, and an infrared monitoring unit, and is used to convert pretreated waste sand into regenerated sand. The cooling module, connected to the thermal regeneration module, is used to convert the regenerated sand into the final regenerated sand; The infrared monitoring unit is configured to generate temperature distribution data, and the temperature distribution data is used to control the flow rate of the inert airflow and the amount of bio-based anti-caking agent added in the airflow addition unit.

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