Three-stage digestion dry production system for calcium hydroxide with high specific surface area

Abstract

The invention relates to the technical field of inorganic chemical materials, in particular to a three-stage digestion dry-process production system of calcium hydroxide with high specific surface area, which comprises a raw material feeding module, a weighing feeder, a metering screw and a pneumatic fluidizing device, the third-stage digester is used for realizing gradient digestion and sufficient mixing of materials; a gas inlet of the bag type dust collector is connected with a gas outlet of the third-stage digester and is used for treating dust-containing gas generated in the digestion process; the powder selecting unit comprises a powder selecting machine and a cyclone separator and is used for separating digested powder into qualified fine powder and unqualified coarse powder; the finished product collecting, storing and transporting module comprises a finished product warehouse for storing qualified finished products and packaging equipment for quantitative packaging; and the PLC automatic control module is in signal connection with the weighing feeder, the three-stage digester, the powder concentrator and the packaging equipment. Therefore, the problems that in the prior art, raw material feeding precision is insufficient, and quick lime is prone to caking are solved.

Description

Technical Field

[0001] This invention relates to the field of inorganic chemical materials technology, specifically to a three-stage dry production system for high specific surface area calcium hydroxide. Background Technology

[0002] Existing technologies primarily focus on the large-scale production of calcium hydroxide, encompassing both traditional wet digestion and early dry digestion processes, providing fundamental raw material support for the industrial sector. The wet process, through the thorough mixing and reaction of quicklime and water, achieves a high conversion rate, meeting the basic needs of applications such as building materials and general desulfurization where product purity requirements are not high. The early dry process simplifies the dehydration stage of the wet process, initially reducing energy consumption by controlling reaction humidity and temperature, and avoiding the large amounts of alkaline waste liquid generated by the wet process. It demonstrates certain applicability in scenarios sensitive to product moisture content, while also accumulating basic parameters and equipment design experience for subsequent optimization of the dry process.

[0003] In traditional high specific surface area calcium hydroxide production processes, there are common problems such as insufficient precision in raw material feeding and easy clumping of quicklime, which often lead to supply interruptions or metering deviations, affecting production stability from the source. Furthermore, single-stage or two-stage digesters, due to poor mixing and incomplete reaction, not only have low digestion efficiency but also produce relatively large calcium hydroxide particles with small specific surface areas, making it difficult to meet the application requirements of high-activity fields. Traditional dust removal equipment has limited efficiency in capturing fine particles, resulting in high dust emission concentrations that fail to meet current environmental standards. Conventional powder classifiers lack sufficient classification accuracy, leading to a high content of coarse particles and poor purity in the finished product, often requiring secondary processing and increasing energy consumption and costs. Traditional processes rely heavily on manual adjustment of key parameters such as digestion temperature and powder classifier speed, making them susceptible to human interference and causing product quality fluctuations. The finished product silo also lacks effective moisture-proofing and anti-caking measures, as calcium hydroxide easily absorbs moisture and clumps, leading to difficulties in unloading and material losses. Summary of the Invention

[0004] This invention provides a three-stage dry production system for high specific surface area calcium hydroxide by digestion, in order to solve technical problems such as insufficient accuracy of raw material feeding and easy clumping of quicklime in the prior art.

[0005] The first aspect of this invention provides a three-stage dry production system for high specific surface area calcium hydroxide, comprising the following steps: the raw material feeding module is used for a weighing feeder for accurately metering quicklime, a metering screw, and a pneumatic fluidization device to promote material flow; the three-stage digester includes a first-stage digestion unit, a second-stage digestion unit, and a third-stage digestion unit connected in sequence, each digestion unit having a horizontal rotating shaft and a dedicated stirring blade mounted thereon for achieving gradient digestion and thorough mixing of materials; the air inlet of the bag filter is connected to the exhaust port of the three-stage digester for treating dust-laden gas generated during digestion; the powder selection unit includes a powder classifier and a cyclone separator for separating the digested powder into qualified fine powder and unqualified coarse powder; the finished product collection and storage module includes a finished product silo for storing qualified finished products and packaging equipment for quantitative packaging; the PLC automatic control module is signal-connected to the weighing feeder, the three-stage digester, the powder classifier, and the packaging equipment, and centrally monitors and adjusts the feed rate, digestion temperature, powder classifier speed, and packaging weight parameters through a preset program.

[0006] Preferably, the outlet temperature of the first-stage digestion unit is controlled at 80-90℃ and is equipped with a multi-point water injection system; the outlet temperature of the second-stage digestion unit is controlled at 90-110℃ to enhance the mixing reaction; and the outlet temperature of the third-stage digestion unit is controlled at 60-70℃ for ventilation, cooling, and preventing agglomeration.

[0007] Preferably, the special stirring blade is a paddle type or a ribbon type structure, with its rotation speed controlled at 100-300 rpm and stirring tension controlled at 20-50 kW.

[0008] Preferably, the quicklime in the raw material feeding module has a calcium oxide content of ≥97% by weight, and the particle size of the crushed particles is 1-5cm.

[0009] Preferably, the classifier is a vortex classifier or a rotor classifier, the speed of the classifying wheel is adjustable in the range of 200-800 rpm, and the air velocity at the inlet of the cyclone separator is controlled at 12-18 m / s.

[0010] Preferably, the finished product warehouse is equipped with a level gauge and an arch-breaking device, and the packaging equipment is a valve-type packaging machine or a ton bag packaging machine.

[0011] Preferably, it further includes a digester addition unit, wherein the digester addition unit includes a storage tank, a metering pump and an atomizing nozzle, the atomizing nozzle being disposed at the feed end of the three-stage digester for uniformly spraying the digester onto the surface of the quicklime particles.

[0012] Preferably, the digestive agent is an aqueous solution of an organic compound having one or more hydroxyl groups, wherein the organic compound is one or more selected from triethanolamine, diethanolamine, ethanolamine, glycerol, propylene glycol, sucrose, or glucose.

[0013] The second aspect of this invention provides a method for a three-stage dry production system of high specific surface area calcium hydroxide, comprising: S1: Raw material feeding and crushing: quicklime is crushed to 1-5cm particles by a crusher, and accurately metered and conveyed to the three-stage digester through a raw material feeding module; S2: Three-stage digestion reaction: granular quicklime and digesting agent are fed into the three-stage digester at a weight ratio of 1.4-1.8:1, and the reaction is carried out under the stirring of a special stirring blade, with the digestion temperature controlled at each stage, and the total digestion time is 30-60 minutes; S3: Dust removal and powder selection: the dust-containing gas generated by digestion is purified by a bag filter, and the solid digestion product enters the powder selection unit to separate and obtain qualified calcium hydroxide fine powder; S4: Finished product collection: the qualified fine powder is conveyed to the finished product warehouse for storage, and finally output as finished product through packaging equipment.

[0014] Preferably, the digestive agent in the three-stage digestion reaction is an aqueous solution containing 0.5%-1.0% by weight of a crystal form control agent, and the finished product has a calcium hydroxide content of ≥92% by weight, a water content of ≤3.5%, and a specific surface area of ​​40-50 m². 2 / g.

[0015] Therefore, the present invention has at least the following beneficial effects: This invention, through its raw material feeding module with its precise metering device and pneumatic fluidization design, enables accurate and continuous feeding of quicklime, effectively avoiding material stagnation and blockage, and providing a reliable pre-feeding guarantee for subsequent stable digestion. The three-stage digester, relying on its graded gradient digestion structure and dedicated stirring blades, promotes full contact and gradual reaction between the quicklime and the digestion medium, significantly improving digestion efficiency and reaction uniformity, reducing undigested coarse particle residue, and directly ensuring the product's core performance characteristics of high specific surface area and high purity. The bag filter efficiently purifies the dust-laden gas during digestion, strictly controlling dust emissions to meet environmental regulations, while improving the production workshop environment and protecting the health of operators. The powder sorting unit... The coordinated sorting by the air classifier and cyclone separator accurately separates qualified fine powder from unqualified coarse powder, ensuring uniform particle size and stable quality of the finished product, significantly improving the product qualification rate. The finished product collection and storage module, with its finished product silo and quantitative packaging equipment, provides convenient storage and standardized packaging of the finished product, adapting to subsequent logistics and diverse customer needs. The PLC automatic control module, through centralized monitoring and automated adjustment of feed rate, digestion temperature, air classifier speed, and packaging weight, reduces errors caused by manual intervention, ensuring a stable and controllable production process. This significantly improves overall production efficiency while reducing labor and energy costs, ultimately achieving efficient, environmentally friendly, and high-quality large-scale production of high specific surface area calcium hydroxide. This solves problems such as insufficient raw material feeding accuracy and easy clumping of quicklime in existing technologies.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 A schematic diagram of a three-stage dry digestion production system for high specific surface area calcium hydroxide provided in an embodiment of the present invention; Figure 2 This is a structural diagram of a three-stage digester provided according to an embodiment of this application; Figure 3 This is a structural diagram of a bag filter provided according to an embodiment of the present invention; Figure 4 This is a structural diagram of an air classifier provided according to an embodiment of the present invention; Figure 5 A schematic diagram of a three-stage dry digestion production system for high specific surface area calcium hydroxide provided in an embodiment of the present invention; Figure 6 A flowchart of a three-stage dry digestion method for producing high specific surface area calcium hydroxide provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0018] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0019] The following description, with reference to the accompanying drawings, describes a three-stage dry production system for high specific surface area calcium hydroxide. Addressing the issue of insufficient raw material feeding accuracy mentioned in the background section, this application provides a three-stage dry production system for high specific surface area calcium hydroxide. In this system, the raw material feeding module, with its precise metering device and pneumatic fluidization design, enables precise and continuous feeding of quicklime, effectively avoiding material stagnation and blockage, and providing a reliable pre-treatment guarantee for subsequent stable digestion. The three-stage digester, relying on a graded gradient digestion structure and dedicated stirring blades, promotes full contact and gradual reaction between quicklime and the digestion medium, significantly improving digestion efficiency and reaction uniformity, reducing undigested coarse particle residue, and directly ensuring the core performance of high specific surface area and high purity of the product. The bag filter efficiently purifies the dust-laden gas during digestion, strictly controlling dust emissions and meeting environmental regulations. The system simultaneously improves the production workshop environment and protects the health of operators. The powder sorting unit, through the coordinated sorting of a powder classifier and a cyclone separator, accurately separates qualified fine powder from unqualified coarse powder, ensuring uniform particle size and stable quality of the finished product, significantly improving the product qualification rate. The finished product collection and storage module, with its finished product silo and quantitative packaging equipment, provides convenient storage and standardized packaging of finished products, adapting to subsequent logistics and transportation and diverse customer needs. The PLC automatic control module, through centralized monitoring and automated adjustment of feed rate, digestion temperature, powder classifier speed, and packaging weight, reduces errors caused by manual intervention, ensuring the stability and controllability of the entire production process. This significantly improves overall production efficiency and reduces labor and energy costs, ultimately achieving efficient, environmentally friendly, and high-quality large-scale production of high specific surface area calcium hydroxide. This solves problems such as insufficient raw material feeding accuracy and easy clumping of quicklime in existing technologies.

[0020] Figure 1 This is a schematic diagram of a three-stage dry production system for high specific surface area calcium hydroxide, provided in an embodiment of this application.

[0021] This application provides a three-stage dry production system for high specific surface area calcium hydroxide, the system 10 including: a raw material feeding module 100, a three-stage digester 200, a bag filter 300, a powder classifier 400, a finished product collection and storage module 500, and a PLC automatic control module 600.

[0022] The raw material feeding module 100 is used for a weighing feeder for precise metering of quicklime, a metering screw, and a pneumatic fluidization device to promote material flow. The three-stage digester 200 includes a first-stage digestion unit, a second-stage digestion unit, and a third-stage digestion unit connected in sequence. Each digestion unit has a horizontal rotating shaft and a special stirring blade installed on it to achieve gradient digestion and thorough mixing of materials. The air inlet of the bag filter 300 is connected to the exhaust port of the three-stage digester to treat the dust-laden gas generated during digestion. The powder classifier 400 includes a powder classifier and a cyclone separator to separate the digested powder into qualified fine powder and unqualified coarse powder. The finished product collection and storage module 500 includes a finished product silo for storing qualified finished products and packaging equipment for quantitative packaging. The PLC automatic control module 600 is connected to the weighing feeder, the three-stage digester, the powder classifier, and the packaging equipment, and centrally monitors and adjusts the feed rate, digestion temperature, powder classifier speed, and packaging weight parameters through a preset program.

[0023] It is understood that the embodiments of this application, through the raw material feeding module with its precise metering device and pneumatic fluidization design, can accurately and continuously feed quicklime, effectively avoiding material stagnation and blockage, and providing a reliable pre-guarantee for subsequent stable digestion; the three-stage digester, relying on its graded gradient digestion structure and dedicated stirring blades, can promote full contact and gradual reaction between quicklime and the digestion medium, significantly improving digestion efficiency and reaction uniformity, reducing undigested coarse particle residue, and directly ensuring the core performance of high specific surface area and high purity of the product; the bag filter efficiently purifies the dust-laden gas during digestion, strictly controlling dust emissions to meet environmental regulations, while improving the production workshop environment and protecting the health of operators; powder selection The unit, through the coordinated sorting of a classifier and a cyclone separator, can accurately separate qualified fine powder from unqualified coarse powder, ensuring uniform particle size and stable quality of the finished product, and significantly improving the product qualification rate. The finished product collection and storage module, with its finished product silo and quantitative packaging equipment, provides convenient storage and standardized packaging of the finished product, adapting to subsequent logistics and transportation and diverse customer needs. The PLC automatic control module, through centralized monitoring and automated adjustment of feed rate, digestion temperature, classifier speed, and packaging weight, reduces errors caused by manual intervention, ensuring the stability and controllability of the entire production process. This significantly improves overall production efficiency and reduces labor and energy costs, ultimately achieving efficient, environmentally friendly, and high-quality large-scale production of high specific surface area calcium hydroxide.

[0024] like Figure 2 As shown, the three-stage digester is the core equipment. Each stage contains a horizontal rotating shaft with a specially designed high-efficiency slurry for continuous mixing of reacting lime and water. The paddle design varies in different digester stages to ensure optimal performance at each specific operating stage. The first stage is equipped with an advanced multi-point water injection system for highly precise control in the initial stages of the digestion process; the second stage involves strong mixing of the materials, allowing the reaction to complete in a second chamber; the third stage features powerfully aerated quicklime to minimize any possible clumping, resulting in a finer digestate exiting the digester.

[0025] like Figure 3 As shown, the digester dust removal uses a bag filter with pulse jet cleaning. This device can ensure that the emission dust content is below 10mg / Nm3 and better control the heat released by the reaction.

[0026] In this embodiment, the outlet temperature of the first-stage digestion unit is controlled at 80-90°C and is equipped with a multi-point water injection system; the outlet temperature of the second-stage digestion unit is controlled at 90-110°C to enhance the mixing reaction; and the outlet temperature of the third-stage digestion unit is controlled at 60-70°C for ventilation, cooling, and anti-caking.

[0027] Among them, a multi-point water injection system is a water injection system that delivers water evenly or as needed to specific objects such as equipment, soil, and reaction vessels by setting up multiple water injection points to meet the needs of cooling, irrigation, and process operation.

[0028] It is understood that the three-stage digestion unit in this application embodiment, through the coordinated design of gradient temperature control and the first-stage multi-point water injection system, can effectively ensure the full slaked of quicklime, avoid material agglomeration, and improve the quality of calcium hydroxide product and its compatibility with subsequent processes. The first-stage digestion unit controls the outlet temperature within a mild range of 80-90℃. Combined with a multi-point water injection system, this ensures uniform contact and slow wetting of quicklime and water. This prevents material agglomeration due to excessive local moisture and avoids under-burning residue caused by insufficient moisture, thus creating a uniform reaction foundation for subsequent deep digestion. The second-stage digestion unit raises the outlet temperature to a highly efficient reaction range of 90-110℃. The high-temperature environment accelerates the chemical reaction rate between quicklime and water. Simultaneously, the powerful mixing action of specialized agitator blades promotes deep and thorough digestion, significantly reducing the content of unreacted quicklime in the finished product and improving the purity and activity of calcium hydroxide. The third-stage digestion unit returns to the 60-70℃ range and uses ventilation for cooling. This quickly removes residual heat from the previous high-temperature reaction, preventing abnormal crystal formation or agglomeration of calcium hydroxide due to continuous high temperatures. It also stabilizes the product's moisture content, ensuring good material flowability. This provides excellent material conditions for the subsequent fine powder separation in the powder selection unit and for the finished product packaging process, ultimately guaranteeing the uniformity of particle size, high specific surface area, and performance stability of the finished calcium hydroxide.

[0029] For example, in a production line with an annual output of 50,000 tons of high specific surface area calcium hydroxide, the temperature control of the three-stage digester is precisely adapted to the reaction requirements of each stage: the first-stage digestion unit adopts a horizontal drum structure with a diameter of 2.2 meters and a length of 8 meters. Eight sets of spiral water injection nozzles are evenly arranged on the inner wall. The outlet temperature sensor data is collected in real time by PLC. When the temperature is lower than the lower limit, the unit automatically starts the water supply pipeline to spray atomized water into the quicklime layer at multiple points (800L of water injection per hour). At the same time, the stirring blades propel the material at a low speed of 15 rpm to complete the initial digestion and release some heat. After the material enters the second-stage digestion unit, the drum speed is increased to 25 rpm to enhance shearing. The matching hot air jacket introduces preheated air to assist in heating. Combined with the exothermic effect of the continuous reaction between quicklime and water, the calcium hydroxide grains grow fully and form a porous structure with a specific surface area of ​​up to 65 m². 2 The final material is transferred to the third-stage digestion unit, where 20°C cold air is introduced through an external heat exchanger to cool the drum jacket. The stirring blades are switched to reverse low-speed (10 rpm) agitation, and the outlet temperature drops to 85°C. This avoids both the hard agglomeration of calcium hydroxide caused by high temperature and the formation of a dense shell due to excessive evaporation of surface moisture. The final product of calcium hydroxide has a stable specific surface area of ​​40-50 m². 2 / g, and there is no clumping, which meets the application requirements of high-end rubber and plastic fillers.

[0030] In this embodiment, the special stirring blade is a paddle type or a ribbon type structure, with its rotation speed controlled at 100-300 rpm and stirring tension controlled at 20-50 kW.

[0031] Among them, stirring tension control refers to the control method that maintains the stability of the tension generated by the stirring shaft, transmission system or material through specific control means during the operation of stirring equipment, so as to ensure the safe operation of the equipment and the stirring effect.

[0032] It is understood that the paddle or ribbon structure in this application embodiment can maximize the material mixing coverage. Combined with a moderate rotation speed of 100-300 rpm, it can ensure that quicklime is fully contacted and uniformly mixed with the digestion medium (such as water) in each digestion unit. This avoids problems such as incomplete digestion or excessive exothermic reactions due to insufficient mixing in certain areas, thereby ensuring the stable progress of the three-stage gradient digestion process and creating uniform reaction conditions for the generation of calcium hydroxide with a high specific surface area. The precise stirring tension of 20-50kW can provide sufficient driving force for the paddles, promoting smooth flow of materials under the drive of the horizontal rotating shaft, effectively preventing material accumulation and clumping in the digester, ensuring production continuity, and avoiding excessive tension that could lead to increased paddle wear or soaring energy consumption. At the same time, with the help of PLC automatic control, it can further maintain the consistency of material mixing and reaction state in each digestion stage, improving the uniformity of the specific surface area of ​​the finished calcium hydroxide and the stability of product quality.

[0033] For example, a factory using a three-stage dry digestion production system has successfully achieved large-scale production of high-specific-surface-area calcium hydroxide by combining a primary paddle type, a secondary ribbon type, and a tertiary ribbon type agitator in its three-stage digester. Specifically: the primary digestion unit uses paddle-type agitators at a speed of 250 rpm and a stirring tension of 40 kW. Through strong shearing action, quicklime particles are rapidly crushed and initially mixed with a measured amount of water to form moist lime particles. The secondary digestion unit switches to ribbon-type agitators, reducing the speed to 150 rpm and adjusting the tension to 25 kW. Utilizing the axial pushing and radial tumbling characteristics of the ribbon, the material reacts fully at a high temperature of 80-100℃, releasing heat and generating calcium hydroxide. The tertiary digestion unit continues the ribbon structure, further reducing the speed to 120 rpm and maintaining the tension at 20 kW. Gentle stirring promotes the aging of incompletely reacted particles, ultimately achieving a digestibility exceeding 95% and a product specific surface area reaching industry-leading levels. This system uses a PLC automatic control module to adjust the stirring parameters at each stage in real time, such as dynamically adjusting the water-cement ratio (1:3.5-1:4.0) according to the digestion temperature. It then separates qualified fine powder of 200-400 mesh through a classifier unit (classifier speed 1000-1200 rpm). The finished product has a free water content of less than 1%, fully meeting the stringent requirements of high-end building materials, flue gas desulfurization, and other fields. Actual operation data shows that compared with the traditional two-stage digestion process, this system increases production capacity by 30%, reduces energy consumption by 15%, and reduces dust emissions to below 30 mg / m³. 3 This has achieved the goal of efficient and environmentally friendly production.

[0034] In this embodiment of the application, the calcium oxide content of the quicklime in the raw material feeding module is ≥97% by weight, and the particle size of the crushed particles is 1-5cm.

[0035] Particle size is a physical quantity used to describe the size of solid particles, usually characterized by the diameter or equivalent diameter of the particle.

[0036] It is understood that the purpose of using a particle size of 1-5 cm after crushing in this embodiment is to optimize the reaction efficiency and system stability of the production process. This particle size range ensures sufficient specific surface area for quicklime to contact with water, promoting rapid initiation and uniformity of the digestion reaction, avoiding incomplete reaction or prolonged digestion cycle due to excessively large particles, while also preventing the risk of violent exothermic reactions and dust explosions caused by excessively small particles, and mitigating damage to the equipment from localized overheating. It is also compatible with the pneumatic fluidization device of the raw material feeding module and the mixing requirements of the three-stage digester. The 1-5 cm particle size provides good flowability, reducing material blockage or accumulation, and ensuring accurate feeding and continuous digestion. The moderate initial particle size results in a more uniform particle size distribution of the calcium hydroxide powder after digestion, which is beneficial for the subsequent powder selection unit to efficiently separate qualified fine powder from coarse particles, improving the high specific surface area characteristics and quality stability of the finished product. The 1-5 cm particle size design is a key parameter for balancing reaction efficiency, system operational safety, and finished product quality.

[0037] For example, in this high specific surface area calcium hydroxide three-stage slaking dry production system, the particle size of quicklime after crushing (1-5cm) refers to the maximum dimension of the crushed quicklime blocks (non-regular cubes, usually measured by the longest or widest side). This can be visually perceived through common everyday objects: fragments of about 1cm have a maximum dimension close to the cross-sectional diameter of an adult's little finger or the side length of a standard die, which is a relatively fine block; fragments of 2-3cm are similar in size to a quail egg, the length of the first joint of an adult's index finger, or about half the width of a regular mahjong tile, which is a medium-sized block; fragments of 4-5cm have a maximum side length comparable to the minor axis of a regular egg, the total length of an adult's thumb, and the longest side of a common rectangular eraser (about 5cm × 2cm × 1cm), which is a larger block within this particle size range. In actual production, although these fragments are not of standard geometric shape, their maximum size must be strictly controlled within the range of 1-5cm. This is to avoid the following problems: if the particles are too large (e.g., exceeding 5cm), it will lead to insufficient digestion in the subsequent three stages and reduced reaction efficiency. It is also to prevent the problems of excessively small particles (e.g., less than 1cm) that will cause serious dust pollution during feeding and blockage of the pneumatic fluidization device. This ensures the accuracy of raw material feeding and the digestion effect.

[0038] In this embodiment of the application, the air classifier is a vortex air classifier or a rotor air classifier, the speed of the classifying wheel is adjustable in the range of 200-800 rpm, and the air velocity at the inlet of the cyclone separator is controlled at 12-18 m / s.

[0039] Among them, the classifying wheel speed refers to the rotation speed of the classifying wheel used to separate materials of different particle sizes in material classification equipment such as air classifiers. Its magnitude directly affects the classification accuracy and the particle size of the final material.

[0040] It is understood that the classifying wheel speed in this embodiment is a core parameter for the precise control of product particle size and specific surface area in the classifier. Its function is to dynamically adjust the particle trajectory in the gas-solid two-phase flow by changing the intensity of the centrifugal force field generated by the rotating classifying wheel: high speed (e.g., 600-800 rpm) enhances centrifugal force, separating finer particles (reduced cutting particle size) and increasing the specific surface area of ​​the finished product; low speed (e.g., 200-400 rpm) reduces separation precision, allowing slightly coarser particles to enter the finished product and avoiding over-grinding. Its advantages lie in the ability to flexibly match different raw material characteristics and process requirements through adjustable speed, precisely controlling the particle size distribution of the calcium hydroxide product and ensuring high specific surface area stability; simultaneously optimizing classification efficiency, reducing fine powder entrainment loss, improving system operating economy, and achieving refined adjustment of the production process in conjunction with PLC automatic control.

[0041] For example, in a three-stage dry digestion production system for high specific surface area calcium hydroxide, the classifier wheel speed needs to be determined based on the finished product particle size requirements, production capacity, and equipment characteristics: for example, for producing particles larger than 200 mesh (D90=45μm, specific surface area 15-20m²), the specific parameters need to be determined in conjunction with the finished product particle size requirements, production capacity, and equipment characteristics. 2 When producing calcium hydroxide for environmental desulfurization or coatings (g / g), if an HLMX1700 rotor classifier (classifying wheel diameter 1.7 m) is configured, the classifying wheel speed is typically set to 450 rpm, and the inlet air velocity of the cyclone separator is 15 m / s, achieving a processing capacity of 15 tons / hour, balancing fineness and dispersibility; if it is necessary to produce calcium hydroxide with a mesh size of 800 or larger (D90=15μm, specific surface area 25-30m²), the processing capacity can be increased. 2 For ultrafine pharmaceutical intermediates (g), when using a JDS-Ⅲ vortex classifier (1.2-meter diameter classifier wheel), the rotation speed needs to be increased to 700 rpm. With an inlet air velocity of 16 m / s, the processing capacity is approximately 8 tons / hour. Micron-level precision separation is achieved by strengthening the centrifugal force field through high rotation speed. For 100-200 mesh (D90=75μm) industrial-grade calcium hydroxide for building mortar or wastewater treatment, a low rotation speed of 300 rpm (2.0-meter diameter classifier wheel) is sufficient to meet the large-scale production capacity requirement of 25 tons / hour, while reducing energy consumption. In actual production, the speed of the classifying wheel also needs to be adjusted in coordination with the wind speed (e.g., for every 100 rpm increase in speed, D90 decreases by about 10-15 μm), and PID closed-loop control is performed by the PLC system based on feedback from the online particle size analyzer (adjustment accuracy ±5 rpm). When the digestion temperature increases, causing the powder to become more viscous, the speed will automatically decrease by 10-20 rpm to prevent the classifying wheel from caking and ensure stable separation efficiency and product quality.

[0042] like Figure 4As shown, the air classifier separator can select products with a purity of 95% up to 45µm. It consists of a selection cage and a cyclone separator. By setting the rotational speed and airflow of the selection cage, and with pressure sensors in the pipeline participating in the control, the stable operation of the air classifier is ensured. The air classifier performs exceptionally well with fine materials. The raw material entering through the inlet is affected by centrifugal force, which evenly distributes the material in the airflow. The rising airflow pushes the material towards the multi-bladed selection cage, where fine powder is discharged into the system collector, while coarse powder is discharged by gravity for further processing.

[0043] In this embodiment of the application, the finished product warehouse is equipped with a level gauge and an arch-breaking device, and the packaging equipment is a valve-mouth packaging machine or a ton bag packaging machine.

[0044] Among them, the valve-mouth packaging machine is a device specifically designed for valve bags, which can automatically complete the filling, degassing and sealing of materials such as granules and powders, and achieve efficient quantitative packaging.

[0045] It is understood that the valve-type packaging machine in this application embodiment, as the core equipment of the finished product collection and storage module in the production system, has multiple key functions and advantages. Adopting a valve-type sealing structure, it can effectively suppress the overflow of dust from high-surface-area calcium hydroxide during the packaging process, meeting environmental protection requirements while preventing material from clumping and contaminating due to moisture absorption or contact with the outside environment, thus maximizing the preservation of the product's activity and high surface-area characteristics. Through signal linkage with the PLC automatic control module, it can accurately measure the packaging weight, automatically seal, and coordinate with the finished product silo level gauge, supporting continuous and stable operation and significantly improving packaging efficiency. The valve design facilitates quick cleaning of residual materials, reducing the risk of cross-contamination between different batches and adapting to the cleanliness requirements of dry production systems. With a high degree of automation, it can seamlessly connect the upstream finished product silo unloading with the downstream storage and transportation links, optimizing the continuity and intelligence level of the overall production process, and enabling efficient, high-quality, and clean storage and transportation of finished products.

[0046] For example, in a three-stage dry digestion production system for high specific surface area calcium hydroxide, the valve-type packaging machine, as the core equipment for quantitative packaging of finished products, often uses specialized models such as the Shanghai Guangzhi GZ-200 double-slope valve-type packaging machine. Its metering range covers 25-50 kg / bag, dynamic error ≤ ±0.2%, and packaging speed reaches 15-30 bags / minute. The material contact parts are made of 304 stainless steel with a PTFE coating to resist alkaline corrosion. It also integrates a pulse-jet dust removal interface and a closed hopper design to ensure that the dust concentration in the workshop is <10 mg / m³. 3To accommodate the agglomeration characteristics of high specific surface area materials, the equipment is equipped with a pneumatic impactor, a high-frequency vibration motor to prevent bridging, and an airbag-type bag clamping system to ensure sealing. Through real-time communication with a PLC automatic control module, it achieves two-stage fast and slow feeding adjustment, finished product bin material level-linked speed control, and production data traceability. In practical applications, it can be integrated with chain conveyors, metal detectors, and robotic palletizers. For example, a chemical company uses its matching three-stage digestion system to produce materials with a specific surface area of ​​18-22 m². 2 With a capacity of 50,000 tons of calcium hydroxide per gram, the system not only reduces the material loss rate from 1.5% to 0.3% and controls the moisture content to 0.3%, but also saves approximately 800,000 yuan in labor and material costs per line per year. At the same time, it meets the requirements of IIB-level explosion protection and low energy consumption, becoming a key link in the system's efficient and environmentally friendly production.

[0047] In this embodiment, the invention further includes a digester addition unit, wherein the digester addition unit includes a storage tank, a metering pump and an atomizing nozzle, the atomizing nozzle being disposed at the feed end of the three-stage digester and used to uniformly spray the digester onto the surface of the quicklime particles.

[0048] The feed end is the port or starting point in the equipment or production system used to input raw materials, semi-finished products, and other materials.

[0049] It is understood that the embodiments of this application can uniformly spray the digester at the initial stage of quicklime entering the digester, so that the digester and quicklime particles can fully contact each other, start the hydration reaction process in advance, and provide a more efficient reaction basis for the subsequent three-stage gradient digestion; atomized spraying can avoid digester agglomeration or local over-displacement, ensure its uniform distribution on the material surface, reduce reaction blind zones, and improve the uniformity and thoroughness of overall digestion; in synergy with the pneumatic fluidization device at the feed end and the subsequent stirring blades, it promotes rapid mixing of digester and material, accelerates the reaction kinetics process, helps to generate finer calcium hydroxide particles, thereby increasing the specific surface area of ​​the product; combined with PLC control to realize the metered addition of digester, it ensures the stability of process parameters, improves the consistency of finished product quality and production efficiency.

[0050] For example, in an industrial production line with an annual output of 50,000 tons of high specific surface area calcium hydroxide, the feed end design of its digester addition unit is as follows: In this production line, the feed end of the three-stage digester is connected to the metering spiral discharge port of the raw material feeding module through an inclined stainless steel chute. Three fan-shaped atomizing nozzles (1.2mm nozzle diameter, 60° atomization angle) are evenly arranged along the material flow direction on the inner wall of the chute. The vertical distance between the nozzle outlet and the material falling trajectory in the chute is controlled at 150mm to ensure that the atomization area completely covers the material flow. The digester is an 8% polyethylene glycol aqueous solution, stored in a 5m³ container. 3In the stainless steel storage tank, the bottom of the tank is connected to a variable frequency metering pump (flow rate adjustable range 0.2-1.5m) via a pipeline. 3 The metering pump has an inlet connection of / h, and its outlet is divided into three branches corresponding to the three atomizing nozzles mentioned above. Each branch is equipped with an electromagnetic flowmeter for real-time flow monitoring. When quicklime is accurately metered by the weighing feeder of the raw material feeding module (e.g., the feed rate is set to 10t / h), and then stably conveyed to the chute by the metering screw and the pneumatic fluidization device (fluidizing air pressure 0.3MPa), the PLC automatic control module will synchronously adjust the frequency of the metering pump according to the real-time feed rate of the weighing feeder, so that the slaking agent flow rate is matched to 5% of the quicklime mass (i.e., the slaking agent flow rate is set to 0.5m³ / h at this time). 3 The atomizing nozzle atomizes the digester into droplets with a diameter of 50-80μm, which are then evenly sprayed onto the surface of the falling quicklime particles. At the same time, a small vibrator (vibration frequency 50Hz) is installed at the bottom of the chute, which, together with the pneumatic fluidization device, further breaks up the slight agglomeration of quicklime particles, ensuring that the atomized digester can fully contact each quicklime particle. Finally, a uniformly mixed material flow enters the first digestion unit of the three-stage digester, laying a uniform reaction foundation for the subsequent gradient digestion process.

[0051] In the embodiments of this application, the digestive agent is an aqueous solution of an organic compound having one or more hydroxyl groups.

[0052] The organic compound is one or more of triethanolamine, diethanolamine, ethanolamine, glycerol, propylene glycol, sucrose, or glucose.

[0053] It is understood that in the embodiments of this application, the Ca generated by the slaked reaction of hydroxyl groups in organic compounds with quicklime (CaO) is... 2 The interaction between the digester and the water process is as follows: Firstly, it precisely controls the reaction rate between CaO and water, preventing material agglomeration caused by sudden temperature rises due to intense local reactions. This ensures gradient and uniform digestion in each stage of the three-stage digester, meeting the mixing requirements of the horizontal rotating shaft and the dedicated stirring blades. Secondly, it inhibits the excessive growth of calcium hydroxide (Ca(OH)2) crystals, promoting the formation of finer particles and a more uniform particle size distribution, directly increasing the specific surface area of ​​the product and meeting the core indicators of high specific surface area products. Simultaneously, the digester improves material flowability, reduces wall formation on the metering screw and the inner wall of the digester unit, and, in conjunction with the pneumatic fluidization device, ensures smooth material transport, reduces the proportion of unqualified coarse powder in the powder selection unit, and increases the yield of qualified finished products. Furthermore, in collaboration with the PLC automatic control module, it can help maintain the stability of parameters such as digestion temperature and material mixing, further ensuring production continuity and product quality consistency.

[0054] For example, in the three-stage dry digestion production system for high specific surface area calcium hydroxide, the digesting agent can be a compound aqueous solution of triethanolamine (TEA) and glycerol. A 0.5-2% (w / w) triethanolamine aqueous solution and a 1-3% (w / w) glycerol aqueous solution are mixed at a volume ratio of 1:1 and then pumped to the first digestion unit of the three-stage digester. Quicklime is quantitatively fed to the digester via a weighing feeder (accuracy ±0.1%) and a metering screw, where it undergoes gradient digestion with the digesting agent solution at 80-100℃: The first-stage digestion unit has a stirring speed set at 300-500 rpm, using specialized stirring blades to rapidly mix the material and digesting agent, generating initial calcium hydroxide intermediates; the second-stage digestion unit reduces the speed to 150-250 rpm, extending the digestion time to 5-8 minutes to promote crystal refinement; the third-stage digestion unit uses low-speed stirring at 50-100 rpm, combined with a PLC automatic control module to monitor the digestion temperature in real time (fluctuation ≤ ±2℃), ultimately producing a product with a specific surface area of ​​40-50 m². 2 / g of highly active calcium hydroxide powder. The mechanism of action of this compound digester is as follows: triethanolamine coordinates with calcium ions through hydroxyl groups, inhibiting the disordered growth of calcium hydroxide crystals and reducing particle surface energy to reduce agglomeration; glycerol acts as a dispersant, with its polyhydroxyl groups adsorbing onto the particle surface to form a physical barrier, enhancing powder flowability and preventing agglomeration. After separation by the powder classifier unit (particle speed 1200-1500 rpm), qualified fine powder (particle size ≤20μm) enters the finished product silo, while unqualified coarse powder is returned to the digester for recycling. This process, through precise control of digester concentration, temperature gradient, and stirring parameters, makes the calcium hydroxide particles exhibit a porous, pleated structure, significantly improving adsorption performance and reactivity, meeting the high-end needs of flue gas desulfurization, wastewater treatment, and other fields.

[0055] This application proposes a three-stage dry production system for high specific surface area calcium hydroxide. Through a precise metering device and pneumatic fluidization design, the raw material feeding module enables accurate and continuous feeding of quicklime, effectively avoiding material stagnation and blockage, and providing a reliable pre-feeding guarantee for subsequent stable digestion. The three-stage digester, relying on a graded gradient digestion structure and dedicated stirring blades, promotes full contact and gradual reaction between quicklime and the digestion medium, significantly improving digestion efficiency and reaction uniformity, reducing undigested coarse particle residue, and directly ensuring the core performance of high specific surface area and high purity of the product. The bag filter efficiently purifies the dust-laden gas during digestion, strictly controlling dust emissions to meet environmental regulations, while improving the production workshop environment and ensuring... Protecting operator health; the powder sorting unit, through the coordinated sorting of a powder sorter and a cyclone separator, can accurately separate qualified fine powder from unqualified coarse powder, ensuring uniform particle size and stable quality of the finished product, significantly improving the product qualification rate; the finished product collection and storage module's finished product silo and quantitative packaging equipment provide convenient storage and standardized packaging of finished products, adapting to subsequent logistics transportation and diverse customer needs; the PLC automatic control module, through centralized monitoring and automated adjustment of feed rate, digestion temperature, powder sorter speed, and packaging weight, reduces errors caused by manual intervention, ensuring the stability and controllability of the entire production process, which not only greatly improves overall production efficiency but also reduces labor and energy costs, ultimately achieving efficient, environmentally friendly, and high-quality large-scale production of high specific surface area calcium hydroxide. This solves the problems of insufficient raw material feeding accuracy and easy clumping of quicklime in existing technologies.

[0056] The following will illustrate a three-stage dry production system for high specific surface area calcium hydroxide through a specific embodiment, such as... Figure 5 As shown, it includes: A certain new materials technology company, as a leading domestic producer of industrial calcium hydroxide, has long faced a bottleneck that traditional processes cannot overcome. While its original "dry grinding + wet digestion" production line could meet basic market demand, the wet digestion process required a large amount of water (8-10 m³ of water per ton of product). 3 It generates alkaline wastewater (pH>12), facing environmental rectification pressure; more importantly, the powder after digestion needs to be dried and dehydrated at high temperature, which not only consumes up to 120kg of standard coal / ton, but also excessive grinding results in a product specific surface area of ​​only 25-30㎡ / g, which cannot meet the stringent requirements of high-activity calcium hydroxide (specific surface area ≥40㎡ / g) in fields such as high-end rubber reinforcing agents and fine chemical catalyst carriers.

[0057] The core of this system lies in its innovative "three-stage gradient digestion + intelligent control" process. Its overall architecture consists of six tightly interconnected modules: a raw material feeding module, a three-stage digester, a bag filter, a powder classifier, a finished product collection and storage module, and a PLC automatic control module. These interconnected modules achieve precise conversion from quicklime to highly active calcium hydroxide. The raw material feeding module, as the starting point of production, directly determines the stability of subsequent reactions. Addressing the pain points of quicklime (CaO content ≥90%, particle size ≤50mm) being prone to moisture absorption and clumping, and inaccurate metering, the system is equipped with a German-imported loss-in-weight balance (SIWAREX WP231) as the core metering device. Its dynamic weighing accuracy reaches ±0.5%, and its metering range covers 0-5t / h. It can adjust the feeding speed in real time according to the processing load of the three-stage digester, ensuring that the feed rate fluctuation is controlled within ±2%. The system also includes a matching 304 stainless steel... The stainless steel metering screw (150mm pitch, adjustable speed 0-60rpm) is responsible for uniformly conveying the weighed quicklime to the pneumatic fluidization device. This device uses 0.4-0.6MPa compressed air to spray pulsed airflow through a φ5mm perforated plate (30% opening rate), causing the quicklime to enter the primary digester in a loose fluidized state. This completely solves the bridging and clogging problems commonly found in traditional feeding. After pretreatment, the quicklime agglomeration rate is reduced from the original 8% to <0.5%, laying the foundation for uniform reaction in the primary digester.

[0058] The three-stage digester is the "heart" of the entire system, employing a series design of three cylindrical units, each φ2.2m × 3.5m in diameter (total volume 12m³). 3 Single stage 4m 3Each stage is equipped with a Φ400mm horizontal rotating shaft (adjustable speed from 8-15 rpm) and 12 sets of "45° forward tilt + swept backward" special stirring blades (16Mn material, 12mm thickness). Unlike the traditional single-stage digester's "one-pot" mode, three-stage gradient temperature control is key: the first stage digestion is set as a pre-digestion stage, with the temperature controlled at 80-90℃. Water is precisely added at 0.8t / h (water-to-ash ratio 0.4:1) through atomized water nozzles, with a stirring speed of 12 rpm and a residence time of 40 minutes. During this stage, the quicklime surface rapidly absorbs water to generate Ca(OH)2, with a conversion rate >85% and an output moisture content of 15%-20%. After the material enters the second stage digester via a screw conveyor, the temperature rises to 90-110℃, and the water spray rate is reduced to 0.3t / h (total water-to-ash ratio 0.4:1). The ratio is 0.55:1), the rotation speed is adjusted to 10 rpm, and the residence time is extended to 60 min. Unreacted CaO continues to hydrate, and the released steam (containing a small amount of CO2) is drawn away by the induced draft fan, reducing the output moisture content to 8%-10% and the CaO conversion rate to >95%. The third-stage digestion is the deep activation stage. Water spraying is stopped, and the residual heat of the material is utilized. The rotation speed is 8 rpm, and the residence time is 90 min. The high temperature and low humidity environment promotes hydroxylation of the Ca(OH)2 crystal surface, forming a dense microporous structure. The specific surface area jumps from 35 m² / g in the second stage to over 45 m² / g. To ensure precise and controllable reaction conditions in the three stages, each digester is equipped with a Pt100 temperature sensor (accuracy ±1℃), a capacitive humidity sensor (accuracy ±2%RH), and a pressure transmitter (monitoring the internal micro-positive pressure to prevent air backflow). The PLC system dynamically adjusts the water spray volume, stirring speed, and induced draft fan frequency based on real-time data.

[0059] The dust-laden gas generated during the digestion process (mainly composed of CaO dust, water vapor, and a small amount of CO2) is collected by a bag filter (LFGM-1200 type, handling air volume 8000m³) through the top pipe of the three-stage digester. 3 This is a crucial link in environmental protection and resource recycling. The dust collector uses PTFE-coated needle-punched felt filter bags (φ160×6000mm, filtration accuracy 0.3μm, efficiency 99.9%), arranged in a matrix of 24 bags, in conjunction with a high-pressure pulse jet cleaning system (air pressure 0.6MPa, cycle 60s, single pulse jet volume 0.15m³ / h). 3 This effectively prevents filter bag clogging; the collected dust (including unreacted CaO fine powder and finished calcium hydroxide) is sent to the powder classifier unit for recycling via a screw conveyor, achieving "zero emissions". Actual measurements show that the dust concentration in the workshop after system operation is <10mg / m³. 3 (far below the national standard of 30mg / m³) 3 The outlet emission concentration of the bag filter is <5mg / m³. 3(Meets ultra-low emission requirements), recovering approximately 120 tons of dust annually, equivalent to saving 15 tons of standard coal, which reduces raw material waste and lowers environmental governance costs.

[0060] The digested material needs further purification and grading in the classifier unit to meet the dual requirements of fineness and activity in the high-end market. The classifier unit consists of an SKS-3000 centrifugal classifier (5t / h capacity) and a Φ1.2m double-volute cyclone separator (90% efficiency): After entering the classifier, the material is thrown up by a high-speed rotating feed disc and encounters the transverse airflow introduced by the guide vanes. Fine powder (specific surface area ≥45㎡ / g, particle size <45μm) is carried by the airflow into the cyclone separator and collected as the finished product, while coarse powder (specific surface area <40㎡ / g, particle size >45μm) falls into the return screw and returns to the secondary digester for re-digestion. Initially, when the classifier speed was set to 1000rpm, the coarse particle content in the finished product was too high (>5%). Technicians adjusted the speed to 1100rpm via PLC and simultaneously increased the induced draft (from 1800m³ / h). 3 / h increased to 2000m 3 ( / h), ultimately reducing the coarse particle content to below 1%, increasing the yield from 85% to 92%, and significantly improving resource utilization.

[0061] Qualified finished calcium hydroxide (specific surface area 45-55 m² / g, Ca(OH)₂ content ≥93%) enters the finished product silo (volume 100 m³) after passing through a cyclone separator. 3 The inner wall is lined with a PE moisture-proof film, and an air cannon is installed at the bottom to prevent arching. A DCS-50 quantitative packaging machine (measuring range 5-50kg / bag, accuracy ±0.2%) is installed at the bottom of the silo. It can automatically switch packaging specifications according to customer needs (e.g., 25kg / bag for export orders, 50kg / bag for domestic orders). After packaging, the products are transported to the warehouse or loaded onto trucks by a belt conveyor. A radar level gauge (accuracy ±10mm) is installed on the top of the finished product silo. When the material level is below 10%, an alarm is triggered to remind timely replenishment, ensuring the stability of continuous production.

[0062] The entire process is intelligently controlled by a Siemens S7-1200 PLC core controller, integrating three major functions: data acquisition, linkage regulation, and fault diagnosis. 28 monitoring points collect real-time data on parameters such as raw material feed rate, temperature / humidity / pressure at each digestion stage, classifier speed, and finished product silo level, which are then visualized via a WinCC host computer. When the primary digestion temperature is abnormal or the bag filter pressure difference exceeds 1500Pa, the system automatically triggers an alarm and sends an SMS to the maintenance personnel's mobile phone, reducing the fault response time from the traditional 30 minutes to 5 minutes. More importantly, the PLC can dynamically optimize the process based on product quality feedback. The main process systems include: ① lime conveying, crushing, storage and screening system; ② calcium hydroxide digestion, powder selection and storage system.

[0063] When the above-mentioned process systems adopt a linked control method, the process operator directly operates the keyboard on the operator station computer to send work instructions to the PLC system, which can then directly monitor and control the entire production process of each system. The industrial control computer monitors the signals of each system in real time, and when a fault occurs, it will issue an alarm or shut down the system after judgment. Level gauges are installed in both the raw material and finished product silos, and the level signals of each silo are displayed in the central control room.

[0064] Since its commissioning, the system has been operating stably, with all indicators exceeding expectations: the specific surface area of ​​the product has remained stable at 48-52㎡ / g (far exceeding the target value of 45㎡ / g), the Ca(OH)2 content has reached 94.5%-95.8% (better than the national standard requirement of 90% for superior grade products), the hydrochloric acid insoluble matter is only 0.12%-0.15% (national standard ≤0.2%), and the residue on the 45μm sieve is 8%-10% (15%-20% for traditional processes), fully meeting the demand for highly active calcium hydroxide in the high-end rubber and fine chemical industries.

[0065] From precise raw material feeding to three-stage gradient digestion, from efficient dust recovery to intelligent storage and transportation of finished products, this high specific surface area calcium hydroxide three-stage digestion dry production system, with technological innovation at its core and intelligent control as its support, not only breaks through the environmental protection and performance bottlenecks of traditional processes, but also proves the feasibility and economy of dry production of highly active calcium hydroxide with actual operation data, providing replicable and scalable practical experience for the green and high-end transformation of traditional chemical enterprises.

[0066] In summary, this embodiment of the high specific surface area calcium hydroxide three-stage digestion dry production system, through the innovative combination of a fully dry process and three-stage gradient digestion, effectively addresses the core pain points of traditional wet processes, such as wastewater pollution, low product activity, and high energy consumption. It integrates technologies such as precise raw material feeding, intelligent temperature-controlled digestion, and dust recycling, resulting in significantly improved product activity, substantial reduction in overall energy consumption, and zero or extremely low wastewater discharge throughout the entire production process. Its deployment enhances market competitiveness and promotes the green transformation of calcium hydroxide production from low-end general-purpose to high-end specialized, providing a replicable model for the implementation and technological upgrading of "dual carbon" practices in traditional chemical enterprises.

[0067] Next, with reference to the accompanying drawings, a method for a three-stage dry production system for high specific surface area calcium hydroxide according to embodiments of this application is described.

[0068] like Figure 6 As shown, the method of this three-stage digestion dry production system for high specific surface area calcium hydroxide includes the following steps: In step S101, raw material feeding and crushing: quicklime is crushed into particles of 1-5cm by a crusher, and then accurately metered and conveyed to the three-stage digester by the raw material feeding module.

[0069] It is understood that, in this embodiment of the application, by crushing quicklime into 1-5cm particles and then accurately metering it through the raw material feeding module before conveying it to the three-stage digester, it can ensure that the quicklime raw material has the particle size required for the subsequent digestion process, ensuring that the subsequent reaction is sufficient and efficient. At the same time, it can also lay the foundation for the stable operation of the entire production process and the control of product quality by accurately metering and controlling the amount of raw material input.

[0070] In step S102, the three-stage digestion reaction is carried out: granular quicklime and digesting agent are fed into the three-stage digester at a weight ratio of 1.4-1.8:1. Under the stirring of special stirring blades, the digestion temperature of each stage is controlled to carry out the reaction. The total digestion time is 30-60 minutes.

[0071] In the tertiary digestion reaction, the digesting agent is an aqueous solution containing 0.5%-1.0% by weight of a crystal form control agent.

[0072] It is understood that, in this embodiment of the application, by adding granular quicklime and digesting agent to a three-stage digester at a weight ratio of 1.4-1.8:1, stirring with a special stirring blade, and precisely controlling the digestion temperature at each stage, while ensuring a total digestion time of 30-60 minutes, the quicklime and digesting agent can be fully contacted and reacted uniformly, effectively improving the thoroughness and stability of the digestion reaction, and avoiding problems such as waste of raw materials and fluctuations in product quality caused by insufficient reaction or uncontrolled conditions.

[0073] In step S103, dust removal and powder selection: the dust-laden gas generated by digestion is purified by a bag filter, and the solid digestion products enter the powder selection unit to separate and obtain qualified calcium hydroxide fine powder.

[0074] It is understood that the embodiments of this application use a bag filter to purify the dust-laden gas generated by the digestion reaction, which can effectively intercept dust particles in the gas, avoid dust emissions from polluting the environment, and the recovered dust can be reused to reduce raw material waste. The solid digestion products are sent to the powder selection unit for separation, which can accurately screen out qualified calcium hydroxide fine powder with particle size and purity that meet the standards, remove impurities and unqualified particles, and ensure that the final product quality is stable and consistent.

[0075] In step S104, finished product collection: qualified fine powder is transported to the finished product warehouse for storage, and finally output as finished product through packaging equipment.

[0076] The finished product contains ≥92% calcium hydroxide by weight, ≤3.5% water, and has a specific surface area of ​​40-50 m². 2 / g.

[0077] It is understood that in this embodiment, qualified calcium hydroxide fine powder is sent to a finished product warehouse for storage and then output through packaging equipment. This not only ensures the stability of product quality during subsequent transportation through the storage function of the finished product warehouse, avoiding the impact of the external environment on product performance, but also achieves standardized product output through a standardized packaging process. Furthermore, it specifies that the finished product has a calcium hydroxide content ≥92%, a water content ≤3.5%, and a specific surface area of ​​40-50 m². 2 The / g index not only strictly controls the quality of the final product, ensuring that it meets the usage requirements of different application scenarios such as building materials and chemicals, but also guarantees the integrity of the production process and the market acceptance of the product.

[0078] This application proposes a three-stage dry production method for high specific surface area calcium hydroxide. Through a raw material feeding module with precise metering and pneumatic fluidization design, it enables accurate and continuous feeding of quicklime, effectively avoiding material stagnation and blockage, and providing a reliable pre-treatment guarantee for subsequent stable digestion. The three-stage digester, relying on a graded gradient digestion structure and dedicated stirring blades, promotes full contact and gradual reaction between quicklime and the digestion medium, significantly improving digestion efficiency and reaction uniformity, reducing undigested coarse particle residue, and directly ensuring the core performance of high specific surface area and high purity of the product. A bag filter efficiently purifies the dust-laden gas during digestion, strictly controlling dust emissions to meet environmental regulations, while simultaneously improving the production workshop environment and ensuring... Protecting operator health; the powder sorting unit, through the coordinated sorting of a powder sorter and a cyclone separator, can accurately separate qualified fine powder from unqualified coarse powder, ensuring uniform particle size and stable quality of the finished product, significantly improving the product qualification rate; the finished product collection and storage module, with its finished product silo and quantitative packaging equipment, enables convenient storage and standardized packaging of finished products, facilitating subsequent logistics and transportation and meeting diverse customer needs; the PLC automatic control module, through centralized monitoring and automated adjustment of feed rate, digestion temperature, powder sorter speed, and packaging weight, reduces errors caused by manual intervention, ensuring the stability and controllability of the entire production process, significantly improving overall production efficiency, and reducing labor and energy costs, ultimately achieving efficient, environmentally friendly, and high-quality large-scale production of high specific surface area calcium hydroxide. This solves the problems of insufficient raw material feeding accuracy and easy clumping of quicklime in existing technologies.

[0079] The following will illustrate the three-stage digestion dry production method of high specific surface area calcium hydroxide through specific examples: Example 1 Quicklime with a calcium oxide content of 97.5% and crushed into 1-3 cm granules was selected as the raw material. The digesting agent was an aqueous solution containing 0.6% by weight of a crystal form control agent (trisodium citrate). The quicklime and digesting agent were simultaneously fed into a three-stage digester connected in series at a weight ratio of 1.5:1. The total duration of the three-stage digestion reaction was controlled at 45 minutes. After the reaction, the purity of the intermediate product (calcium hydroxide) was found to be 96.8%, with uniform particle size, no unreacted quicklime particles remaining, and a stable crystal structure, meeting the quality requirements for subsequent deep processing.

[0080] Example 2 Granular quicklime with a calcium oxide content of 98.2% and a particle size of 3-5 cm was selected. The digesting agent was prepared as an aqueous solution containing 0.8% by weight of a crystal form control agent (sodium hexametaphosphate). The material was fed into a three-stage digester at a quicklime to digesting agent weight ratio of 1.7:1. The speed of the special stirring blade was adjusted to 35 r / min to ensure sufficient contact between the material and the digesting agent in each stage of the digester. The total digestion time was set to 50 minutes. After the reaction was completed, samples were taken for testing. The intermediate product, calcium hydroxide, had a purity of 97.2% and a specific surface area of ​​18.5 m². 2 / g, the crystal regularity is improved by 23% compared with the control group without crystal control agent, effectively avoiding product agglomeration caused by local overheating of reaction, and the material flowability is significantly enhanced in subsequent processes.

[0081] Example 3 Using granular quicklime with a calcium oxide content of 97.2% and a particle size of 2-4 cm as raw material, and an aqueous solution containing 1.0% by weight of a crystal form control agent (sodium pyrophosphate), the quicklime and digesting agent were fed into a three-stage digester at a weight ratio of 1.4:1. The stirring blades were kept at a speed of 28 r / min, and the total digestion time was shortened to 35 minutes. After the reaction, the purity of the intermediate product calcium hydroxide was 96.5%, and the content of unreacted quicklime was only 0.3%, far below the 1.0% residual standard of conventional industry processes. Moreover, the particle size distribution of the product was concentrated in 10-20 μm, with excellent crystal form stability. No moisture absorption or deterioration occurred during subsequent storage, further verifying the reliability of this three-stage digestion process in terms of efficiency and quality control.

[0082] Figure 7 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: The memory 701, the processor 702, and the computer program stored on the memory 701 and executable on the processor 702.

[0083] When processor 702 executes the program, it implements the three-stage digestion dry production method of high specific surface area calcium hydroxide provided in the above embodiments.

[0084] Furthermore, electronic devices also include: Communication interface 703 is used for communication between memory 701 and processor 702.

[0085] The memory 701 is used to store computer programs that can run on the processor 702.

[0086] The memory 701 may include high-speed RAM (Random Access Memory) memory, and may also include non-volatile memory, such as at least one disk storage.

[0087] If the memory 701, processor 702, and communication interface 703 are implemented independently, then the communication interface 703, memory 701, and processor 702 can be interconnected via a bus to complete communication between them. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0088] Optionally, in a specific implementation, if the memory 701, processor 702, and communication interface 703 are integrated on a single chip, then the memory 701, processor 702, and communication interface 703 can communicate with each other through an internal interface.

[0089] The processor 702 may be a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of this application.

[0090] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0091] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0092] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0093] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (FPGAs), field-programmable gate arrays (FPGAs), etc.

[0094] Those skilled in the art will understand that all or part of the steps of the methods implementing the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0095] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A three-stage dry digestion production system for high specific surface area calcium hydroxide, characterized in that, include: The system includes a raw material feeding module, a three-stage digester, a bag filter, a powder classifier, a finished product collection and storage module, and a PLC automatic control module; among which... The raw material feeding module is used for a weighing feeder for accurately measuring quicklime, a metering screw, and a pneumatic fluidization device to promote material flow. The three-stage digester includes a first-stage digestion unit, a second-stage digestion unit, and a third-stage digestion unit connected in sequence. Each digestion unit is equipped with a horizontal rotating shaft and a special stirring blade installed on it to achieve gradient digestion and thorough mixing of materials. The air inlet of the bag filter is connected to the exhaust outlet of the three-stage digester to treat the dust-laden gas generated during the digestion process. The powder selection unit includes a powder classifier and a cyclone separator, which are used to separate the digested powder into qualified fine powder and unqualified coarse powder. The finished product collection and storage module includes a finished product warehouse for storing qualified finished products and packaging equipment for quantitative packaging; The PLC automatic control module is connected to the weighing feeder, the three-stage digester, the powder classifier, and the packaging equipment. It centrally monitors and adjusts the feeding amount, digestion temperature, powder classifier speed, and packaging weight parameters through a preset program.

2. The three-stage digestion dry production system for high specific surface area calcium hydroxide according to claim 1, characterized in that, The outlet temperature of the first-stage digestion unit is controlled at 80-90℃ and is equipped with a multi-point water injection system. The outlet temperature of the second-stage digestion unit is controlled at 90-110℃ to enhance the mixing reaction. The outlet temperature of the third-stage digestion unit is controlled at 60-70℃ for ventilation, cooling and anti-caking.

3. The three-stage digestion dry production system for high specific surface area calcium hydroxide according to claim 1, characterized in that, The special stirring blades are of paddle or ribbon type, with a rotation speed controlled at 100-300 rpm and a stirring tension controlled at 20-50 kW.

4. The three-stage digestion dry production system for high specific surface area calcium hydroxide according to claim 1, characterized in that, The quicklime in the raw material feeding module has a calcium oxide content of ≥97% by weight, and the particle size of the crushed particles is 1-5cm.

5. The three-stage digestion dry production system for high specific surface area calcium hydroxide according to claim 1, characterized in that, The air classifier is a vortex air classifier or a rotor air classifier, and the speed of its classifying wheel is adjustable from 200 to 800 revolutions per minute. The air velocity at the inlet of the cyclone separator is controlled at 12 to 18 m / s.

6. The three-stage digestion dry production system for high specific surface area calcium hydroxide according to claim 1, characterized in that, The finished product warehouse is equipped with a level gauge and an arch-breaking device, and the packaging equipment is a valve-type packaging machine or a ton bag packaging machine.

7. The three-stage digestion dry production system for high specific surface area calcium hydroxide according to claim 1, characterized in that, Also includes: The digester addition unit includes a storage tank, a metering pump, and an atomizing nozzle. The atomizing nozzle is located at the feed end of the three-stage digester and is used to uniformly spray the digester onto the surface of quicklime particles.

8. The three-stage digestion dry production system for high specific surface area calcium hydroxide according to claim 7, characterized in that, The digestive agent is an aqueous solution of an organic compound having one or more hydroxyl groups, wherein the organic compound is one or more of triethanolamine, diethanolamine, ethanolamine, glycerol, propylene glycol, sucrose, or glucose.

9. A method for producing high specific surface area calcium hydroxide using a three-stage digestion dry process system as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: Raw material feeding and crushing: Quicklime is crushed into 1-5cm particles by a crusher, and then accurately metered and conveyed to the three-stage digester through the raw material feeding module; S2: Three-stage digestion reaction: Granular quicklime and digesting agent are fed into the three-stage digester at a weight ratio of 1.4-1.8:

1. Under the stirring of special stirring blades, the digestion temperature of each stage is controlled to carry out the reaction. The total digestion time is 30-60 minutes. S3: Dust removal and powder selection: The dust-laden gas generated by digestion is purified by a bag filter, and the solid digestion products enter the powder selection unit to separate and obtain qualified calcium hydroxide fine powder; S4: Finished product collection: The qualified fine powder is transported to the finished product warehouse for storage, and finally output as a finished product through packaging equipment.

10. The three-stage digestion dry production method for high specific surface area calcium hydroxide according to claim 9, characterized in that, The digestive agent in the three-stage digestion reaction is an aqueous solution containing 0.5%-1.0% by weight of a crystal form control agent. The finished product has a calcium hydroxide content of ≥92% by weight, a water content of ≤3.5%, and a specific surface area of ​​40-50 m². 2 / g.

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