Preparation process of real stone sand

Abstract

The invention discloses a preparation process of real stone sand, and relates to the technical field of building decoration, and the real stone sand is prepared from the following materials in parts: 450-650 parts of natural quartzite coarse aggregate, 80-120 parts of feldspar powder, 150-220 parts of a Portland cement binder, 25-40 parts of a nanometer alumina reinforcing agent, 3-8 parts of a polycarboxylate superplasticizer, and 1.5-3.5 parts of a silane coupling agent KH-550. 8-15 parts of a water glass modulus regulator and 180-250 parts of deionized water. According to the preparation process of the real stone sand provided by the invention, the real stone sand is ensured to have a firm structural foundation and excellent durability by strictly screening and optimally proportioning the raw materials, and the particle size distribution of aggregate is effectively controlled and the porosity of a formed body is reduced by adopting a three-stage crushing and fine screening technology, so that the compressive strength is improved; the interface strengthening treatment and the gradient mixing technology are applied, so that the binding force between the aggregate and the binder is remarkably enhanced, the problems of cement agglomeration and non-uniform distribution of the water reducing agent are avoided, and the real stone sand is excellent in mechanical property.

Description

Technical Field

[0001] The present invention relates to the technical field of architectural decoration, and particularly to a preparation process of real stone sand. Background Art

[0002] With the continuous growth of the demand for high-performance artificial stone in the fields of architectural decoration and road engineering, real stone sand, as an important composite material to replace natural stone, has attracted much attention. Traditional preparation processes mostly adopt simple mechanical crushing combined with conventional sintering methods. Although the basic performance requirements can be met, there are significant bottlenecks in core indicators such as material density, interfacial bonding strength, and weather resistance. The existing technology generally adopts a single-stage crushing and screening process, resulting in a large dispersion in the aggregate particle size distribution, which directly affects the mechanical properties of the products; the interfacial treatment mostly relies on physical mixing, and it is difficult to form a chemical bonding enhancement effect; the temperature control in the sintering process is rough, which easily causes problems such as incomplete crystal phase transformation and residual stress concentration. In response to the above industry pain points, new preparation technologies have begun to explore innovative directions such as nano-material modification, gradient mixing process, and intelligent sintering control, aiming to break through the performance ceiling of traditional processes and achieve the coordinated improvement of key indicators such as high strength, low water absorption, and freeze-thaw cycle resistance.

[0003] The current real stone sand preparation technology faces multiple challenges: First, the conventional crushing system is difficult to accurately control the aggregate gradation, and the wide particle size distribution leads to a high porosity of the formed body, and the compressive strength is generally lower than 120 MPa; Second, the interfacial treatment mostly uses simple coating of silane coupling agent, lacking the construction of a nano-level strengthening layer, and the interfacial peeling rate reaches more than 8% after acid-base environment testing; Third, the mixing process mostly uses single-speed stirring, which is prone to cement agglomeration and uneven distribution of water reducing agent, and the fluidity fluctuation range of the slurry exceeds ±30 mm; Fourth, the sintering process mostly adopts a constant temperature curve, which cannot accurately control the conversion ratio of mullite and quartz phases, and the products have insufficient high-temperature sudden change resistance; Fifth, the post-treatment process lacks surface nano-strengthening means, and the roughness Ra value after polishing is mostly higher than 1.6 μm, affecting the decorative effect. More importantly, the existing process has not established a parameter optimization model, resulting in an energy consumption as high as 1.8 times that of traditional ceramics, and the finished product qualification rate has long hovered around 85%. In response to this, we propose a preparation process of real stone sand. Summary of the Invention

[0004] To solve the above technical problems, a preparation process of real stone sand is provided, and this technical solution solves the above problems.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A preparation process of real stone sand, and the real stone sand is prepared from the following parts of materials: 450-650 parts of natural quartzite coarse aggregate, 80-120 parts of feldspar powder, 150-220 parts of silicate cement binder, 25-40 parts of nano-aluminum oxide enhancer, 3-8 parts of polycarboxylate water reducer, 1.5-3.5 parts of silane coupling agent KH-550, 8-15 parts of water glass modulus regulator, and 180-250 parts of deionized water.

[0007] Preferably, the real stone sand is specifically prepared from the following parts of materials: 510 parts of natural quartzite coarse aggregate, 95 parts of feldspar powder, 165 parts of silicate cement binder, 34 parts of nano-aluminum oxide enhancer, 5 parts of polycarboxylate water reducer, 2 parts of silane coupling agent KH-550, 10 parts of water glass modulus regulator, and 210 parts of deionized water.

[0008] Preferably, the preparation method is as follows:

[0009] S1. Raw material pretreatment and gradation optimization: The quartzite coarse aggregate is subjected to three-stage crushing and screening, and the particle size distribution is controlled in the range of 0.15-4.75 mm.

[0010] S2. Interface strengthening treatment: The surface of the aggregate is activated by using a composite modifier.

[0011] S3. Gradient mixing: Different components are added in stages and the mixing parameters are adjusted.

[0012] S4. High-pressure molding: The preform is molded under a specific pressure curve.

[0013] S5. Controllable sintering: Multi-temperature zone gradient heat treatment is implemented.

[0014] S6. Post-treatment and detection: including surface polishing, performance testing and packaging.

[0015] Preferably, the S1 step specifically includes:

[0016] Jaw crushers are used for three-stage crushing, and it is required that the primary crushing particle size meets ≤80 mm, the cone crusher requires the secondary crushing to meet ≤30 mm, and the vertical shaft impact crusher requires the final crushing to meet ≤5 mm.

[0017] The screening system is equipped with a 5-layer vibrating screen, and the screen mesh numbers are 4 mesh, 10 mesh, 20 mesh, 40 mesh, and 80 mesh in sequence. The aggregates of each particle size are compounded according to the following ratio:

[0018] 4-10 mesh (4.75-2.36 mm) accounts for 35±2%, 10-20 mesh (2.36-0.85 mm) accounts for 28±1.5%, 20-40 mesh (0.85-0.425 mm) accounts for 22±1%, and 40-80 mesh (0.425-0.18 mm) accounts for 15±0.8%.

[0019] During the crushing process, an electromagnetic iron removal device is installed at the outlet of each stage of equipment, and the iron impurity content is controlled at ≤0.02%.

[0020] Preferably, the interface strengthening treatment in step S2 includes:

[0021] Aggregate pre-activation: Place the graded aggregate in an inclined drum with a rotation speed of 28-35r / min, spray with 5-8% hydrofluoric acid solution accounting for 0.6% to 1.2% of the aggregate mass, and treat for 15-25 minutes;

[0022] Coupling agent coating: ultrasonic atomization device is used, with a frequency of 28kHz and a power density of 0.5W / cm 2 , spray the mixture of silane coupling agent and nano-alumina in a ratio of 1:0.3-0.6 evenly on the aggregate surface;

[0023] Thermal curing: In a fluidized bed device, hot air circulation treatment is performed at 120-150°C for 30-50 minutes to form a strengthening interface layer with a thickness of 80-120nm.

[0024] Preferably, the S3 gradient mixing process is implemented in three stages:

[0025] The first stage of dry mixing: add pre-treated aggregate, feldspar powder and cement binder into the double planetary mixer, mix at a low speed of 35-45r / min for 8-12min, and simultaneously open the jacket cooling water to keep the material temperature ≤40℃;

[0026] The second stage is semi-wet mixing: add water reducer and 50% water, increase the speed to 60-80r / min and mix for 15-20min, control the vacuum degree at -0.06~-0.08MPa, and the coefficient of variation of mixing uniformity CV≤3%;

[0027] The third stage of wet mixing: inject the remaining water and additives, and mix in an alternating mode of high speed 120-150r / min and low speed 45r / min. After each 2 minutes of high speed mixing, mix at low speed for 5 minutes, with a total mixing time of 25-35 minutes. The slurry fluidity reaches 180-220mm.

[0028] Preferably, the S4 high pressure forming process parameters are:

[0029] Use a 3000t hydraulic press with a mold system to implement a three-stage pressurization method:

[0030] Initial pressure is 50-80MPa and maintained for 30s to make the material dense;

[0031] The mid-term pressure is increased to 120-150 MPa and maintained for 60-90 seconds to expel internal bubbles;

[0032] Apply impact pressure of 180 - 220 MPa in the later stage, with a pulse width of 0.5 - 1 s and an interval of 3 s, and cycle 3 - 5 times. The density of the formed body reaches 2.65 - 2.75 g / cm 3 , and the moisture content is controlled at 5.5 - 6.8%.

[0033] Preferably, the S5 controllable sintering process includes:

[0034] Preheating section: Heat up to 450 - 500 °C at a rate of 8 - 12 °C / min and keep warm for 1 - 1.5 h to remove residual moisture;

[0035] Medium - temperature section: Heat up to 900 - 950 °C at a rate of 15 - 18 °C / min, introduce a mixed gas with a volume ratio of nitrogen to oxygen of 4:1, and maintain for 2 - 2.5 h to complete the reconstruction of the silicate network;

[0036] High - temperature section: Heat up to 1250 - 1280 °C at a rate of 5 - 8 °C / min, introduce a CO2 atmosphere with a concentration of 30 - 40 vol%, and keep warm for 3 - 4 h to form mullite crystal phase;

[0037] Gradient cooling: First, rapidly cool to 800 °C at a rate of 25 - 30 °C / min, and then slowly cool to room temperature at a rate of 8 - 10 °C / min. The total crystal phase content is ≥88%, among which the mullite phase is ≥65% and the quartz phase is ≤15%.

[0038] Preferably, the S6 post - treatment includes:

[0039] Surface treatment: Conduct five - level polishing using a diamond grinding wheel (grit #200 - #2000), and the surface roughness Ra ≤ 0.8 μm;

[0040] Reinforcement treatment: Immerse in a silica sol containing 5 - 8% nano - SiO2 and form a protective layer of 30 - 50 nm through heat treatment at 120 °C;

[0041] Quality inspection: Include four core indicators: compressive strength (≥150 MPa), water absorption rate (≤0.5%), abrasion resistance (worn pit diameter ≤ 28 mm),

[0042] acid - alkali corrosion resistance (mass loss ≤ 1.2% after soaking in 5% HCl / NaOH for 72 h);

[0043] Intelligent sorting: Use a machine vision system to classify the color and cracks, and the surface defect area of grade A products is ≤ 0.05%.

[0044] Preferably, the production equipment configuration includes: raw material pretreatment system, mixing system and sintering furnace

[0045] Raw material pretreatment system: Equipped with an on - line particle size analyzer (laser diffraction method) and an automatic feedback adjustment device to realize real - time monitoring and closed - loop control of the crushing particle size;

[0046] Mixing system: The double planetary mixer is equipped with a torque sensor (range 0 - 500 N·m, accuracy ±0.5% FS) and an infrared moisture combined measurement device (detection range 0 - 20%, resolution 0.1%);

[0047] Sintering kiln: Adopts a full fiber module structure, equipped with a 32 - zone independent temperature control system (temperature control accuracy ±2°C) and a multi - atmosphere precise gas distribution device, with a flow control accuracy of ±0.5 L / min;

[0048] It also includes the following quality control systems:

[0049] Establish a process parameter optimization model based on big data. The key parameters collected include but are not limited to: raw material particle size distribution, mixing torque curve, and sintering temperature gradient. Establish a mapping relationship between process parameters and performance indicators through neural network algorithms, and adjust operation variables such as crusher gap, mixer speed, and sintering heating rate in real - time to ensure that the qualified product rate ≥ 99.3%;

[0050] At the same time, use blockchain technology to record the raw material traceability, process parameters, and test data of each batch of products throughout the process.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0052] The preparation process of the real stone sand proposed by the present invention ensures that the real stone sand has a solid structural foundation and excellent durability through strictly screened and optimized - ratio raw materials. The use of three - stage crushing and fine screening technologies effectively controls the particle size distribution of the aggregate, reduces the porosity of the formed body, thereby improving the compressive strength. The application of interface strengthening treatment and gradient mixing technology significantly enhances the bonding force between the aggregate and the binder, avoiding problems such as cement agglomeration and uneven distribution of water - reducing agents, making the real stone sand perform excellently in mechanical properties. The high - pressure forming and controllable sintering processes further optimize the microstructure and phase composition of the real stone sand, improving its high - temperature rapid - change resistance and overall stability. Brief Description of the Drawings

[0053] Figure 1 It is the flowchart of the method of the present invention. Detailed Embodiments

[0054] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations.

[0055] The excellent performance of real stone sand starts from its scientific and reasonable raw material formula. With natural quartzite coarse aggregate as the main component, its dosage is between 450 - 650 parts. Precise control of this ratio can ensure that real stone sand has a solid structural foundation. The quartzite coarse aggregate is strictly screened, and its source needs to be stable and of excellent quality, with characteristics such as high hardness, wear resistance, and strong chemical stability, which can effectively improve the overall strength and durability of real stone sand. Feldspar powder, as an auxiliary component, has a content between 80 - 120 parts. It plays a key role in improving the fluidity and sintering performance of the material in the system, promoting the uniform mixing and synergistic reaction among various raw materials, and enhancing the forming effect of real stone sand. The dosage of Portland cement binder is 150 - 220 parts, and its strong binding ability is the core force to tightly combine various raw materials, ensuring the stable structural integrity of real stone sand after forming. The addition amount of nano-aluminum oxide enhancer is between 25 - 40 parts. With its nano-scale size effect and high activity, it significantly enhances the mechanical properties of real stone sand, making it excellent in aspects such as compressive resistance and wear resistance. The addition of 3 - 8 parts of polycarboxylate water reducer can effectively adjust the rheological properties of the system, reduce the water-cement ratio, and improve the strength and density of real stone sand without affecting the workability. The dosage of silane coupling agent KH-550 is 1.5 - 3.5 parts. Its unique molecular structure can build a solid bridge between organic and inorganic materials, strengthening the interfacial bonding force between the aggregate and the binder. 8 - 15 parts of water glass modulus regulator is used to precisely control the modulus of water glass, optimize its bonding and curing performance, and ensure the stable performance of real stone sand. 180 - 250 parts of deionized water provides the necessary medium environment for the mixing and reaction of various raw materials, ensuring the smooth progress of the preparation process. In actual production, a formula combination of 510 parts of natural quartzite coarse aggregate, 95 parts of feldspar powder, 165 parts of Portland cement binder, 34 parts of nano-aluminum oxide enhancer, 5 parts of polycarboxylate water reducer, appropriate amount of silane coupling agent KH-550, appropriate amount of water glass modulus regulator, and appropriate amount of deionized water is often adopted. This formula has been verified by a large number of practices, achieving the best balance between cost and benefit while meeting the performance requirements.

[0056] Referring to Figure 1 As shown, a preparation process of real stone sand, its preparation method process is as follows:

[0057] Raw material pretreatment and gradation optimization (S1): Raw material pretreatment is the key starting link in the preparation of real stone sand. The crushing of quartzite coarse aggregate adopts a three-stage crushing process. A jaw crusher is selected for primary crushing, and its powerful crushing ability can control the raw material particle size within ≤80mm, laying a foundation for subsequent processing. A cone crusher is responsible for secondary crushing, further refining the particle size to ≤30mm to ensure that the particle size gradually meets the requirements. A vertical shaft impact crusher is used for final crushing, enabling the aggregate particle size to precisely meet the strict standard of ≤5mm. The screening system is equipped with a 5-layer vibrating screen, and the mesh numbers of the screens are 4 mesh, 10 mesh, 20 mesh, 40 mesh, and 80 mesh in sequence. Through a carefully designed screening process, aggregates of each particle size are compounded in a specific proportion: 4 - 10 mesh (4.75 - 2.36mm) accounts for 35 ± 2%, and this particle size aggregate provides good skeleton support in the system; 10 - 20 mesh (2.36 - 0.85mm) accounts for 28 ± 1.5%, which helps to fill the skeleton gaps and enhance the material density; 20 - 40 mesh (0.85 - 0.425mm) accounts for 22 ± 1%, further optimizing the particle gradation; 40 - 80 mesh (0.425 - 0.18mm) accounts for 15 ± 0.8%, enabling the material to achieve close packing at the microscopic level. At the outlet of each stage of equipment in the crushing process, an electromagnetic iron removal device is installed. Its high sensitivity can effectively adsorb and remove iron impurities, ensuring that the iron impurity content is strictly controlled within ≤0.02%, preventing iron impurities from having an adverse impact on the performance of real stone sand, and ensuring the purity and stability of product quality.

[0058] Interface strengthening treatment (S2): The interface strengthening treatment aims to improve the bonding efficiency between the aggregate and the binder. First, the aggregate is pre-activated. The graded aggregate is placed in an inclined drum with a rotation speed of 28 - 35r / min, and a hydrofluoric acid solution with a concentration of 5 - 8% and accounting for 0.6% - 1.2% of the aggregate mass is uniformly added through a spray system, and the treatment time lasts for 15 - 25min. The hydrofluoric acid solution can moderately corrode the surface of the aggregate, increasing its surface roughness and active sites, providing favorable conditions for the attachment of subsequent modifiers. Subsequently, coupling agent coating is carried out. An ultrasonic atomization device is used, and its specific frequency of 28kHz and power density of 0.5W / cm 2 can ensure that a solution in which the silane coupling agent and nano-aluminum oxide are mixed in a ratio of 1:0.3 - 0.6 is uniformly dispersed and precisely sprayed on the surface of the aggregate. The organic functional groups of the silane coupling agent react chemically with the surface of the aggregate, and the inorganic part acts synergistically with nano-aluminum oxide to enhance the bonding performance of the interface. Finally, heat treatment and curing are carried out. In a fluidized bed device, hot air circulation at 120 - 150°C is used for 30 - 50min, promoting the formation of a strong chemical bond between the coupling agent and the surface of the aggregate, and successfully constructing a strengthened interface layer with a thickness of 80 - 120nm on the surface of the aggregate, significantly improving the overall performance of real stone sand.

[0059] Gradient mixing (S3): The gradient mixing process is divided into three fine stages. In the first stage, dry mixing, the pretreated aggregate, feldspar powder, and cement binder are added to a double planetary mixer and stirred at a low speed of 35 - 45 r / min for 8 - 12 min. Meanwhile, the jacket cooling water is turned on to ensure that the material temperature is stable at ≤40°C. Stirring at a low speed in this stage can avoid material flying and excessive friction, and the circulating cooling water effectively prevents the change of raw material properties or the premature reaction of the binder due to heat generated by friction. In the second stage, semi-wet mixing, water reducing agent and 50% of the water are added, the rotation speed is increased to 60 - 80 r / min and stirred for 15 - 20 min, and the vacuum degree is precisely controlled at -0.06 - -0.08 MPa to ensure that the coefficient of variation of the mixing uniformity CV ≤ 3%. In a vacuum environment, the materials are mixed more fully, and the addition of the water reducing agent and water adjusts the rheological properties of the materials, promoting the uniform dispersion of each component. In the third stage, wet mixing, the remaining water and additives are injected, and an alternating mode of high speed 120 - 150 r / min and low speed 45 r / min is used for stirring. After every 2 min of high-speed mixing, it is switched to low-speed mixing for 5 min, with a total duration of 25 - 35 min, so that the fluidity of the slurry reaches 180 - 220 mm. This alternating stirring method can not only ensure the full mixing of the materials but also prevent the generation of bubbles or material agglomeration due to over-stirring, ensuring that the slurry has good fluidity and stability and meets the requirements of subsequent forming processes.

[0060] High-pressure forming (S4): In the high-pressure forming link, a 3000t hydraulic press and a mold system are used, and an innovative "three-stage pressurization method" is adopted. In the initial stage, a pressure of 50 - 80 MPa is applied and held for 30 s. The pressure in this stage promotes the initial densification of the material, fills the mold cavity, and lays a foundation for subsequent forming. In the middle stage, the pressure is increased to 120 - 150 MPa and maintained for 60 - 90 s. The higher pressure effectively discharges the air bubbles inside the material, further improving the densification and uniformity of the material. In the later stage, an impact pressure of 180 - 220 MPa, a pulse width of 0.5 - 1 s, and an interval of 3 s is applied, and it is circulated 3 - 5 times. This impact pressure mode can further compact the material without damaging the material structure, so that the density of the formed body reaches 2.65 - 2.75 g / cm 3 , and the moisture content is precisely controlled at 5.5 - 6.8% to ensure that the formed real stone sand products have excellent properties of high strength and low porosity.

[0061] Controlled Sintering (S5): The controlled sintering process involves multiple key temperature zones and atmosphere control steps. In the preheating section, the temperature is raised at a rate of 8 - 12 °C / min to 450 - 500 °C and held for 1 - 1.5 h. The main purpose of this process is to slowly remove the residual moisture in the material and prevent the products from cracking or deforming due to rapid evaporation of moisture. In the medium-temperature section, the temperature is raised at a rate of 15 - 18 °C / min to 900 - 950 °C, and a mixed gas with a volume ratio of nitrogen to oxygen of 4:1 is introduced and maintained for 2 - 2.5 h. Under these temperature zone and atmosphere conditions, the silicate network is reconstructed, enhancing the chemical bonding force and structural stability of the material. In the high-temperature section, the temperature is raised at a rate of 5 - 8 °C / min to 1250 - 1280 °C, and a CO2 atmosphere with a concentration of 30 - 40 vol% is introduced and held for 3 - 4 h to promote the formation of mullite crystal phase, which is a key step in improving the high-temperature performance and mechanical properties of real stone sand. Finally, gradient cooling is carried out. First, it is rapidly cooled to 800 °C at a rate of 25 - 30 °C / min, and then slowly cooled to room temperature at a rate of 8 - 10 °C / min to ensure that the total crystal phase content is ≥88%, with the mullite phase ≥65% and the quartz phase ≤15%, obtaining an ideal combination of crystal phase structure and properties.

[0062] Post-treatment and Testing (S6): The post-treatment stage is crucial for improving the performance and quality control of real stone sand products. For surface treatment, five-level polishing is carried out using a diamond grinding wheel (grit #200 - #2000). Through a gradually refined polishing process, the surface roughness Ra of the product is ≤0.8 μm, obtaining a smooth and flat surface to meet the appearance requirements of decoration or specific industrial applications. For strengthening treatment, the product is impregnated with a silica sol containing 5 - 8% nano-SiO2 and heat-treated at 120 °C to form a protective layer with a thickness of 30 - 50 nm on the surface of the product, effectively improving the wear resistance and corrosion resistance of the product. Quality testing includes four core indicators: compressive strength (≥150 MPa), water absorption rate (≤0.5%), abrasion resistance (wear scar diameter ≤28 mm), and acid and alkali corrosion resistance (mass loss ≤1.2% after soaking in 5% HCl / NaOH for 72 h) to ensure that the product performance meets high-standard requirements. In the intelligent sorting link, an advanced machine vision system is used to accurately classify the appearance defects such as color and cracks of the products. Among them, the surface defect area of Class A products is ≤0.05%, ensuring the consistency and reliability of product quality and meeting the requirements of different application scenarios.

[0063] III. Overview of Advanced Configuration of Production Equipment

[0064] Raw material pretreatment system: The raw material pretreatment system is equipped with an on-line particle size analyzer (laser diffraction method) and an automatic feedback adjustment device, forming an intelligent closed-loop control system. The on-line particle size analyzer monitors the particle size change of quartzite coarse aggregate during the crushing process in real time. Based on the laser diffraction principle, it can accurately measure the particle size distribution and transmit the data to the automatic feedback adjustment device immediately. This device automatically adjusts the working parameters of the crusher according to the preset particle size standard, such as the jaw plate gap of the jaw crusher, the eccentricity of the cone crusher, and the rotation speed of the vertical shaft impact crusher, etc., to ensure that the crushing particle size is always stable within the specified range, realizing high-precision and automatic control of raw material pretreatment, and providing a raw material basis with uniform particle size and stable quality for the subsequent production process.

[0065] Mixing system: The core equipment of the mixing system, the double planetary mixer, integrates a torque sensor (range 0 - 500 N·m, accuracy ±0.5% FS) and an infrared moisture combined measurement device (detection range 0 - 20%, resolution 0.1%). The torque sensor monitors the torque change during the mixing process in real time. Through the torque data, the mixing state, uniformity degree of the material, and whether there is agglomeration phenomenon can be intuitively reflected. The infrared moisture combined measurement device accurately measures the moisture content in the material, providing an accurate basis for moisture addition during the gradient mixing process. Operators can adjust parameters such as the rotation speed of the mixer, mixing time, and material addition sequence in a timely manner according to the data feedback from the sensors, ensuring that each raw material is evenly dispersed and fully reacted during the mixing process, guaranteeing the stability and consistency of the slurry quality, and meeting the strict requirements of the real stone sand preparation process for the mixing link.

[0066] Sintering kiln: The sintering kiln adopts a full-fiber module structure, with excellent heat insulation performance and thermal stability, effectively reducing energy consumption and improving the uniformity of the temperature field in the kiln. The kiln is equipped with a 32-zone independent temperature control system (temperature control accuracy ±2°C) and a multi-gas precise gas distribution device (flow control accuracy ±0.5 L / min). The 32-zone independent temperature control system can achieve precise independent control of the temperature in each area of the kiln according to the different temperature zone requirements of the controllable sintering process of real stone sand, ensuring that the material can be accurately heated up, kept warm, and cooled down according to the preset temperature curve during the preheating, medium-temperature, high-temperature, and cooling stages, and obtaining an ideal crystal phase structure and performance. The multi-gas precise gas distribution device accurately controls the flow rate and proportion of gases such as nitrogen, oxygen, CO2, etc. according to the chemical reaction requirements in each stage of the sintering process, creating a suitable atmosphere environment, promoting the smooth progress of key reactions such as the reconstruction of the silicate network and the formation of mullite crystal phase, and ensuring the sintering quality and performance stability of real stone sand.

[0067] Process Parameter Optimization Model Based on Big Data: Building a process parameter optimization model based on big data is one of the core technical means to ensure the stable quality of real stone sand. By comprehensively collecting key parameters during the production process, including massive data such as raw material particle size distribution, mixing torque curve, sintering temperature gradient, etc., and using neural network algorithms to establish an accurate mapping relationship between process parameters and performance indicators. For example, correlating the particle size data of different batches of raw materials with the performance data such as the compressive strength and water absorption rate of the final product to explore the internal laws behind the data. Based on this model, operating variables such as crusher gap, mixer speed, and sintering heating rate can be adjusted in real-time and dynamically. When the raw material particle size distribution fluctuates, the model automatically calculates and adjusts the crusher parameters to ensure that the performance of subsequent products is not affected; during the mixing process, the stirring parameters are optimized in a timely manner according to the change of the torque curve to ensure the uniformity of material mixing; in the sintering process, the furnace temperature control system is accurately regulated based on the temperature gradient data to ensure the accuracy and stability of the sintering process, enabling the qualified rate of finished products to be stably at a high level of ≥99.3%, and realizing intelligent quality control in the production process of real stone sand.

[0068] Full-process Evidence Preservation Application of Blockchain Technology: The blockchain technology is used to preserve the evidence of the raw material traceability, process parameters, and test data of each batch of products throughout the process, providing reliable traceability and verification guarantees for the quality of real stone sand. From the mining source of natural quartzite coarse aggregate, information such as its origin and quality is recorded, to the detailed parameters of each process step during the production process, such as the operating parameters of each stage of crushing equipment, the mixing time and speed, the temperature curve and atmosphere control data of sintering, and then to the various quality inspection results of the final product. All data are stored on the blockchain in encrypted form. This makes the information of the product transparent, tamper-proof, and traceable throughout its life cycle. Once a quality problem occurs in the product, the root cause of the problem can be quickly traced through the blockchain. Whether it is the quality defect of the raw material or the process deviation during the production process, it can be accurately located and targeted measures can be taken to improve it, effectively enhancing the product quality control level and the enterprise's reputation, and protecting the rights and interests of consumers and the market competitiveness.

[0069] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, various changes and improvements will occur to the present invention, and all these changes and improvements fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation process of real stone sand, characterized in that, The real stone sand is prepared from the following parts of materials: 450 - 650 parts of natural quartzite coarse aggregate, 80 - 120 parts of feldspar powder, 150 - 220 parts of silicate cement binder, 25 - 40 parts of nano-aluminum oxide enhancer, 3 - 8 parts of polycarboxylate water reducer, 1.5 - 3.5 parts of silane coupling agent KH-550, 8 - 15 parts of water glass modulus regulator, and 180 - 250 parts of deionized water.

2. The preparation process of artificial stone sand according to claim 1, characterized in that Specifically, the real stone sand is prepared from the following parts of materials: 510 parts of natural quartzite coarse aggregate, 95 parts of feldspar powder, 165 parts of silicate cement binder, 34 parts of nano-aluminum oxide enhancer, 5 parts of polycarboxylate water reducer, 2 parts of silane coupling agent KH-550, 10 parts of water glass modulus regulator, and 210 parts of deionized water.

3. The preparation process of a kind of real stone sand according to claim 1, characterized in that, The preparation method is as follows: S1. Raw material pretreatment and gradation optimization: The quartzite coarse aggregate is subjected to three-stage crushing and screening, and the particle size distribution is controlled in the range of 0.15 - 4.75 mm. S2. Interface strengthening treatment: The surface of the aggregate is activated by using a composite modifier. S3. Gradient mixing: Different components are added in stages and the mixing parameters are adjusted. S4. High-pressure molding: The preform is formed under a specific pressure curve. S5. Controllable sintering: Multi-temperature zone gradient heat treatment is implemented. S6. Post-treatment and testing: including surface polishing, performance testing and packaging.

4. The preparation process of a real stone sand according to claim 1, characterized in that The specific content of step S1 includes: Jaw crushers are used for the three-stage crushing. The primary crushing particle size is required to meet ≤80 mm, the cone crusher requires the secondary crushing to meet ≤30 mm, and the vertical shaft impact crusher requires the final crushing to meet ≤5 mm. The screening system is equipped with a 5-layer vibrating screen, and the mesh numbers of the screens are 4 mesh, 10 mesh, 20 mesh, 40 mesh, and 80 mesh in sequence. The aggregates of each particle size are compounded in the following proportions: 4 - 10 mesh (4.75 - 2.36 mm) accounts for 35 ± 2%, 10 - 20 mesh (2.36 - 0.85 mm) accounts for 28 ± 1.5%, 20 - 40 mesh (0.85 - 0.425 mm) accounts for 22 ± 1%, and 40 - 80 mesh (0.425 - 0.18 mm) accounts for 15 ± 0.8%. An electromagnetic iron removal device is set at the outlet of each stage of equipment during the crushing process, and the iron impurity content is controlled at ≤0.02%.

5. The preparation process of a kind of real stone sand according to claim 1, characterized in that, The interface strengthening treatment in step S2 includes: Aggregate pre-activation: The graded aggregate is placed in an inclined drum with a rotation speed of 28 - 35 r / min, and a hydrofluoric acid solution with a concentration of 5 - 8% and accounting for 0.6% - 1.2% of the aggregate mass is added by spraying, and the treatment time is 15 - 25 min. Coupling agent coating: An ultrasonic atomization device with a frequency of 28 kHz and a power density of 0.5 W / cm 2 is used to evenly spray a mixed solution of silane coupling agent and nano-aluminum oxide on the surface of the aggregate at a ratio of 1:0.3 - 0.6; Heat treatment and curing: In a fluidized bed equipment, hot air circulation treatment is carried out at 120 - 150 °C for 30 - 50 min to form a strengthening interface layer with a thickness of 80 - 120 nm.

6. The preparation process of a real stone sand according to claim 1, characterized in that, The S3 gradient mixing process is implemented in three stages: The first-stage dry mixing: The pretreated aggregate, feldspar powder, and cement binder are added to a double planetary mixer and mixed at a low speed of 35 - 45 r / min for 8 - 12 min, and the jacket cooling water is simultaneously turned on to keep the material temperature ≤40 °C. The second stage is semi-wet mixing: Add water reducing agent and 50% of the water, increase the rotation speed to 60 - 80 r / min and mix for 15 - 20 min, control the vacuum degree at -0.06 ~ -0.08 MPa, and the coefficient of variation of mixing uniformity CV ≤ 3%; The third stage is wet mixing: Inject the remaining water and additives, and mix in an alternating mode of high speed 120 - 150 r / min and low speed 45 r / min. After every 2 min of high-speed mixing, mix at low speed for 5 min, with a total duration of 25 - 35 min, and the slurry fluidity reaches 180 - 220 mm.

7. The preparation process of a kind of real stone sand according to claim 1, characterized in that, The process parameters of S4 high-pressure forming are: Use a 3000t hydraulic press with a die system and implement a three-stage pressure application method: The initial pressure is 50 - 80 MPa and keep the pressure for 30 s to densify the material; The medium-term pressure is increased to 120 - 150 MPa and maintained for 60 - 90 s to discharge internal air bubbles; Apply impact pressure of 180 - 220 MPa in the later stage, with pulse width of 0.5 - 1 s and interval of 3 s, and cycle 3 - 5 times, so that the density of the formed body reaches 2.65 - 2.75 g / cm 3 , and control the moisture content at 5.5 - 6.8%.

8. The preparation process of a real stone sand according to claim 1, characterized in that, The controllable sintering process of S5 includes: Preheating section: Heat up at a rate of 8 - 12 °C / min to 450 - 500 °C and keep warm for 1 - 1.5 h to remove residual moisture; Medium-temperature section: Heat up to 900 - 950 °C at a rate of 15 - 18 °C / min, introduce a mixed gas with a volume ratio of nitrogen to oxygen of 4:1, and maintain for 2 - 2.5 h to complete the reconstruction of the silicate network; High-temperature section: Heat up to 1250 - 1280 °C at a rate of 5 - 8 °C / min, introduce a CO2 atmosphere with a concentration of 30 - 40 vol%, and keep warm for 3 - 4 h to form mullite crystal phase; Gradient cooling: First, cool rapidly at a rate of 25 - 30 °C / min to 800 °C, and then cool slowly at a rate of 8 - 10 °C / min to room temperature. The total crystal phase content ≥ 88%, among which the mullite phase ≥ 65% and the quartz phase ≤ 15%.

9. The preparation process of a real stone sand according to claim 1, characterized in that, The post-treatment of S6 includes: Surface treatment: Perform five-level polishing with a diamond grinding wheel (grit #200 - #2000), and the surface roughness Ra ≤ 0.8 μm; Reinforcement treatment: Immerse in silica sol containing 5 - 8% nano-SiO2 and form a protective layer of 30 - 50 nm after heat treatment at 120 °C; Quality inspection: Include four core indicators: compressive strength (≥ 150 MPa), water absorption rate (≤ 0.5%), wear resistance (wear pit diameter ≤ 28 mm), Acid and alkali corrosion resistance (mass loss ≤ 1.2% after soaking in 5% HCl / NaOH for 72 h); Intelligent sorting: Use a machine vision system to classify the color and cracks, and the surface defect area of grade A products ≤ 0.05%.

10. The preparation process of a true stone sand according to claim 1, wherein, The production equipment configuration includes: raw material pretreatment system, mixing system and sintering furnace Raw material pretreatment system: Equipped with an on-line particle size analyzer (laser diffraction method) and an automatic feedback adjustment device to realize real-time monitoring and closed-loop control of the crushing particle size; Mixing system: The double planetary mixer is configured with a torque sensor (range 0 - 500 N·m, accuracy ± 0.5% FS) and an infrared moisture combined measurement device (detection range 0 - 20%, resolution 0.1%); Sintering furnace: Adopt a full fiber module structure, equipped with a 32-zone independent temperature control system (temperature control accuracy ± 2 °C) and a multi-atmosphere precise gas distribution device, and the flow control accuracy is ± 0.5 L / min; It also includes the following quality control systems: Build a process parameter optimization model based on big data, and collect key parameters including but not limited to: raw material particle size distribution, mixing torque curve, and sintering temperature gradient. Establish the mapping relationship between process parameters and performance indicators through neural network algorithms, and adjust operation variables such as crusher gap, mixer speed, and sintering heating rate in real time to ensure that the qualified rate of finished products ≥ 99.3%; At the same time, use blockchain technology to record the whole process of raw material traceability, process parameters, and test data of each batch of products.

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