A solid sodium silicate preparation process based on sectional temperature control roasting

Abstract

The application discloses a solid sodium silicate preparation process based on segmented temperature control roasting and relates to the technical field of inorganic chemical material preparation. The process comprises raw material proportioning, uniform mixing, segmented temperature control roasting and post-processing. The application matches the physical and chemical reaction requirements in stages, makes the reaction more stable and complete, significantly improves the conversion rate, and basically eliminates the unreacted cores. The "rapid cooling + slow cooling" procedure is adopted, so that the product has a glass body state with high whiteness and high transparency, small internal stress, high mechanical strength, and the appearance quality and physical performance are significantly improved; the process has strong adaptability: by adjusting the temperature and time parameters of each stage, the process can flexibly adapt to the requirements of different raw material specifications and the production of different modulus products. The application accurately controls the temperature, time and atmosphere of each stage, solves the problems of uneven reaction and poor product quality in the traditional process, and realizes the preparation of solid sodium silicate with high conversion rate, high whiteness and low internal stress.

Description

Technical Field

[0001] This invention relates to the field of inorganic chemical material preparation technology, specifically to a method for preparing solid sodium silicate (sodium silicate) by calcination. Background Technology

[0002] Sodium silicate, commonly known as sodium silicate, is an inorganic substance with the chemical formula Na2O·nSiO2. Its aqueous solution is commonly known as water glass, which is an adhesive. As a soluble inorganic silicate, it has a wide range of applications.

[0003] Traditional processes for preparing solid sodium silicate mainly utilize reverberatory furnaces or tunnel kilns for melting reactions, which have the following significant drawbacks: 1. Low thermal efficiency: A single high-temperature zone or simple temperature control leads to a large waste of thermal energy; 2. Uneven reaction: Uneven heating of materials within the kiln easily results in localized overheating (leading to increased energy consumption and equipment wear) and incomplete localized reactions (forming "sand cores" (unreacted quartz sand cores), affecting product quality); 3. Unstable product quality: The heating and cooling processes cannot be precisely controlled, resulting in low product whiteness, high internal stress and easy breakage, or excessive crystal precipitation, affecting subsequent dissolution rates and application performance; 4. High energy consumption and heavy pollution: Outdated thermal processes lead to high energy consumption per unit of product, failing to meet green manufacturing requirements. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by providing a solid sodium silicate preparation process based on segmented temperature-controlled calcination. This process improves reaction efficiency and product uniformity through precise temperature and time control, significantly enhancing product whiteness and vitreous quality, while simultaneously achieving cascaded energy utilization, thus achieving the comprehensive goals of energy saving, consumption reduction, quality improvement, and efficiency enhancement.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a process for preparing solid sodium silicate based on segmented temperature-controlled calcination, the specific steps of which are as follows:

[0006] Step 1: Raw material ratio: Accurately weigh quartz sand and soda ash, wherein the quartz sand has a SiO2 content ≥98.5% and a particle size of 80-200 mesh, and the soda ash has a Na2CO3 content ≥98.5%, and accurately mix the materials according to a SiO2 to Na2O molar ratio of 2.0-3.3;

[0007] Step 2: Homogenization: Put the prepared raw materials into a high-efficiency mixer and mix for no less than 30 minutes to ensure that the material composition is highly uniform and avoid local chemical measurement deviations caused by uneven mixing. In order to reduce dust entrainment in the kiln and improve heat transfer, the mixed powder is pressed into tablets or granulated into discs to form uniform raw material particles with a particle size of 3-10mm.

[0008] Step 3: Segmented temperature-controlled roasting. The pretreated raw material is fed into a roasting equipment with segmented precise temperature control function for segmented roasting reaction.

[0009] Step 4: The solid glass, cooled to below 800°C, is further processed according to the final product requirements: For solid products, it can be directly packaged into block products, or crushed and screened into granular products of a specific particle size; for liquid products, the above solid blocks or granules are put into a pressure dissolving tank, heated and dissolved by steam, to prepare liquid sodium silicate.

[0010] As a further aspect of the present invention: the segmented temperature-controlled calcination in step three includes the following stages:

[0011] Phase 1: Low-temperature dehydration and preheating section; Temperature range: programmed temperature increase from room temperature to 200℃-600℃; Heating rate: slow heating rate, strictly controlled at 3-8℃ / min, to ensure sufficient evaporation of physical water without causing material splashing; Residence time: total residence time of material in this temperature zone is 20-40 minutes; Atmosphere and environment: inlet temperature 50-100℃, air volume 1-3 Nm³. 3 / kg of material is heated with hot air to carry away moisture and expel it;

[0012] Second stage: Medium-temperature reaction initiation stage; Temperature range: 800℃-900℃; Heating rate: Use a medium heating rate, controlled at 5-10℃ / min; Holding time: After reaching the upper limit of the target temperature, hold at this temperature range for 15-30 minutes; Atmosphere and environment: Maintain a weak oxidizing atmosphere to ensure that organic impurities are fully decomposed.

[0013] Third stage: High-temperature full reaction zone; Temperature range: Rapidly increase the temperature from the third stage reaction temperature to 1250℃-1350℃; Heating rate: Use a rapid heating rate, ideally 10-15℃ / min, to reduce component volatilization and heat loss at high temperatures, promote rapid melting reaction, and reduce the impact of volume effect; Holding time: Hold at this core reaction temperature zone for 30-60 minutes; The holding time needs to be adjusted according to the particle size, modulus, and target conversion rate of the material; Atmosphere and environment: Maintain a stable and calm melting environment, avoiding strong airflow agitation that could lead to uneven component volatilization;

[0014] Fourth stage: Controlled cooling section; Temperature range: Cooling from the reaction temperature of the third stage to below 800℃ (near the glass transition temperature of sodium silicate); Cooling rate: Two-stage program-controlled cooling; First stage (rapid cooling): Rapid cooling from the discharge temperature to 1000℃, with the rate controlled at 15-25℃ / min; This stage is crucial for suppressing crystal precipitation; Second stage (slow cooling): Slow cooling from 1000℃ to below 800℃, with the rate controlled at 5-10℃ / min.

[0015] As a further embodiment of the present invention: the roasting equipment in step three includes a stepped base, and the base is provided with a first roasting furnace, a second roasting furnace, a third roasting furnace and a fourth roasting furnace arranged in stages from top to bottom. The top of the first roasting furnace, the second roasting furnace, the third roasting furnace and the fourth roasting furnace are all fixedly connected to exhaust pipes. The inner cavity of the first roasting furnace, the second roasting furnace, the third roasting furnace and the fourth roasting furnace are all equipped with combustion equipment. The materials in the first roasting furnace, the second roasting furnace and the third roasting furnace are all conveyed by a conveying mechanism. The fourth roasting furnace moves the materials out through a discharge mechanism.

[0016] A first hot air inlet pipe is provided on the top wall of the first roasting furnace, and a second hot air inlet pipe is provided on the top wall of the third roasting furnace. The first and second hot air inlet pipes are respectively connected to a hot air source through an air pump. One or more air inlets are provided on the side wall of the fourth roasting furnace, and each of the air inlets is connected to an induced draft air pump through a solenoid valve and an induced draft pipe.

[0017] As a further embodiment of the present invention: the conveying mechanism includes a feed pipe, which is fixedly connected to the outer wall of the first roasting furnace. A feed hopper is fixedly connected to the top end of the feed pipe. A reaction chamber is fixedly connected to the inner cavity of each of the first, second, and third roasting furnaces. A conveying pipe extending to the next roasting furnace is fixedly connected to the outer wall of the reaction chamber. A conveying motor is installed on the outer wall of the conveying pipe, and a conveying shaft is connected to the output end of the conveying motor. A storage trough is formed at the top of the reaction chamber, and a connecting groove is formed at the bottom of the storage trough. The connecting groove communicates with the inner cavity of the conveying pipe. The top ends of the first, second, and third roasting furnaces... Each component is equipped with a first motor, the output end of which is connected to a first threaded rod. A displacement frame is slidably connected to the outer wall of the first threaded rod, and the displacement frame is slidably connected to the outer wall of the reaction chamber. A scraper is fixedly connected to one end of the displacement frame. A baffle is rotatably connected to the inner cavity of the connecting groove. A connecting shaft is fixedly connected to one end of the baffle, and a spur gear is fixedly connected to one end of the connecting shaft. A vertical rod is slidably connected inside the reaction chamber, and the vertical rod contacts the spur gear. A spring is connected between the bottom end of the vertical rod and the reaction chamber. An extrusion block is slidably connected inside the reaction chamber to one side of the vertical rod, and one end of the extrusion block extends out of the reaction chamber.

[0018] As a further embodiment of the present invention: the discharge mechanism includes a furnace door, which is rotatably connected to the outer wall of the fourth roasting furnace. A support plate is fixedly connected to the outer wall of the base on one side of the fourth roasting furnace. A second motor is installed on the outer wall of the fourth roasting furnace. A second threaded rod is connected to the output end of the second motor. A displacement seat is slidably connected to the outer wall of the second threaded rod. The displacement seat is slidably connected to the bottom end of the inner wall of the fourth roasting furnace. A groove is provided at the top of the displacement seat. A collection box is slidably connected to the inner wall of the groove. Connecting rods are rotatably connected to both sides of the displacement seat. A connecting seat is rotatably connected to one end of the connecting rod. The connecting seat is fixedly connected to the furnace door.

[0019] As a further embodiment of the present invention: the displacement frame is n-shaped and the outer wall of the top end is provided with a first threaded hole, the first threaded hole matching the first threaded rod; the outer wall of the scraper frame is in contact with the inner wall of the storage tank.

[0020] As a further embodiment of the present invention: the end of the extrusion block extending out of the reaction chamber is provided with an inclined surface, the inclined surface being located below the displacement frame.

[0021] As a further embodiment of the present invention: the outer wall of the vertical rod is provided with an inclined groove, and the extrusion block is in contact with the inclined groove.

[0022] As a further embodiment of the present invention: the outer wall of the vertical rod is provided with a toothed groove, which meshes with the spur gear.

[0023] As a further embodiment of the present invention: the outer wall of the displacement seat is provided with a second threaded hole, the second threaded hole is matched with the second threaded rod, and the inner wall of the groove is in contact with the outer wall of the collection box.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. Improved preparation process enhances reaction efficiency and quality: By matching the physicochemical reaction requirements in stages, the reaction becomes more stable and thorough, significantly improving the conversion rate, essentially eliminating unreacted nuclei, and resulting in excellent chemical homogeneity of the product; superior product quality: The unique "rapid cooling + slow cooling" process ensures that the product has a vitreous state with high whiteness and high transparency, low internal stress, high mechanical strength, and significantly improved appearance quality and physical properties; strong process adaptability: By adjusting the temperature and time parameters at each stage, it can flexibly adapt to the needs of different raw material specifications and the production of products with different moduli.

[0026] 2. To complement the improved production process, the present invention further modifies the roasting equipment. The roasting equipment is equipped with a conveying mechanism. The first motor drives the displacement frame to move, which in turn pushes the extrusion block to move. The displacement of the extrusion block pushes the vertical rod to move, which in turn drives the spur gear to rotate. The rotation of the spur gear drives the baffle to rotate, and the rotation of the baffle opens the connecting groove. The material enters the conveying pipe through the connecting groove. At the same time, the scraper scrapes the inner wall of the storage tank, removing the material adhering to the inner wall of the storage tank. The rotation of the conveying shaft drives the material through the conveying pipe into the next roasting furnace, facilitating the transfer of material from one roasting furnace to the next.

[0027] 3. The roasting equipment is equipped with a discharge mechanism, and the material falls into the collection box for collection. The second motor drives the displacement seat to move, and the displacement seat moves the collection box. At the same time, the displacement seat pushes the furnace door to rotate through the connecting rod. The rotation of the furnace door opens the fourth roasting furnace, and the displacement seat moves out from the opening of the fourth roasting furnace. At this time, the collection box can be taken out from the groove, so that when the fourth roasting furnace is opened, the collection box can be automatically moved out, making it convenient to take out the material from the fourth roasting furnace. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the calcination equipment described in this invention;

[0029] Figure 2 This is a schematic diagram of the internal structure of the roasting equipment described in this invention;

[0030] Figure 3 This is a schematic diagram of the internal structure of the first and second roasting furnaces of the roasting equipment described in this invention;

[0031] Figure 4 This is a schematic diagram of the internal structure of the reaction chamber of the calcination equipment described in this invention;

[0032] Figure 5 This is a schematic diagram of the scraper frame of the roasting equipment described in this invention;

[0033] Figure 6 This is a schematic diagram of the structure of the vertical rod of the roasting equipment described in this invention;

[0034] Figure 7 This is a schematic diagram of the internal structure of the fourth roasting furnace in the roasting equipment described in this invention;

[0035] Figure 8 This is a schematic diagram of the installation structure of the displacement seat of the roasting equipment described in this invention.

[0036] In the diagram: 1. Base; 2. First roasting furnace; 3. Second roasting furnace; 4. Third roasting furnace; 5. Fourth roasting furnace; 6. Exhaust pipe; 7. Combustion equipment; 8. Conveying mechanism; 801. Feed hopper; 802. Feed pipe; 803. Reaction chamber; 804. Conveying pipe; 805. Conveying motor; 806. Conveying shaft; 807. Storage tank; 808. Connecting groove; 809. First motor; 810. First threaded rod; 811. Displacement frame; 812. Scraper 813. Moving frame; 814. Baffle; 815. Connecting shaft; 816. Spur gear; 817. Vertical rod; 818. Spring; 819. Extrusion block; 900. Discharge mechanism; 901. Furnace door; 902. Support plate; 903. Second motor; 904. Second threaded rod; 905. Displacement seat; 906. Groove; 907. Collection box; 908. Connecting rod; 909. Connecting seat; 10. First hot air inlet pipe; 11. Second hot air inlet pipe; 12. Air inlet. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," and "set up" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The following describes embodiments of the invention based on its overall structure. Example 1

[0039] Please see Figures 1 to 8 In this embodiment of the invention, a preparation process for solid sodium silicate with a modulus of 2.5 based on segmented temperature-controlled calcination is described, with the following specific steps:

[0040] Step 1: Raw material ratio: Accurately weigh 100-mesh quartz sand (SiO2 content 99.0%) and soda ash (Na2CO3 content 99.0%), and accurately mix them according to the SiO2 / Na2O molar ratio of 2.5.

[0041] Step 2: Mixing and homogenization: Put the prepared raw materials into a high-efficiency mixer and mix for 40 minutes. Then, granulate the mixed powder into uniform raw material particles with a particle size of 5-7mm using a disc granulator.

[0042] Step 3: Segmented temperature-controlled roasting:

[0043] Phase 1: The temperature is programmed to rise from room temperature to 400°C at a rate of 5°C / min, with the material held for 30 minutes; an airflow of 80°C and a flow rate of 2 Nm³ is introduced. 3 Hot air per kg of material.

[0044] The second stage involves heating from 400℃ to 850℃ at a rate of 8℃ / min, holding the temperature for 20 minutes to maintain a low oxygen concentration atmosphere with an oxygen volume fraction of 2%-5%.

[0045] The third stage involves rapidly increasing the temperature from 850°C to 1250°C at a rate of 12°C / min, and holding this temperature for 45 minutes to maintain a stable and calm melting environment.

[0046] Fourth stage: Starting from 1250℃, the temperature is programmed to cool down. The rapid cooling section (1250℃ to 1000℃) is cooled at a rate of 20℃ / min; the slow cooling section (1000℃ to 800℃) is cooled at a rate of 8℃ / min.

[0047] Step 4: Post-processing: The solid glass body cooled to below 800℃ is crushed and sieved to obtain granular solid sodium silicate product with a particle size of 2-5mm.

[0048] In this embodiment: The first stage mainly removes adsorbed water, interlayer water, and some crystal water from the raw materials. Slow heating allows moisture to diffuse steadily from the inside out, preventing the material from "bursting" and pulverizing due to excessive internal vapor pressure caused by rapid surface drying and crusting. This prepares a structurally stable material bed for subsequent high-temperature reactions.

[0049] The second stage, a crucial transition from solid-phase to liquid-phase reaction, occurs above approximately 600℃. At this stage, soda ash (Na₂CO₃) begins its polycrystalline transformation and melts at around 850℃. The molten soda ash then wets the surface of the quartz sand (SiO₂) particles, initiating a preliminary solid-liquid reaction to form initial low-melting-point substances such as sodium metasilicate (Na₂SiO₃), creating a molten layer coating the sand particles. Appropriate heating and holding ensure a smooth initiation of the reaction, allowing the melt to slowly form and connect, creating a favorable interface for the next stage of vigorous reaction. This also prevents excessive decomposition of the soda ash (Na₂CO₃ → Na₂O + CO₂) due to rapid heating, or premature sintering of the material surface that would close the internal reaction channels.

[0050] The third stage is the region where the main reaction Na2CO3+nSiO2→Na2O·nSiO2+CO2↑ is fully carried out. The high temperature causes a large increase in the initially formed eutectic material and a decrease in viscosity. The quartz sand particles gradually dissolve and diffuse into the melt. Sufficient residence time is the key to ensuring complete reaction and eliminating "sand cores", and finally forming a uniform and clear sodium silicate melt.

[0051] In the fourth stage, rapid cooling quickly allows the melt to pass through the temperature range where certain sodium silicate crystals (such as the crystal morphology of sodium silicate itself) are most likely to precipitate, "freezing" the disordered structure at high temperatures, thereby forming a glass with high transparency and whiteness. This effectively prevents the product from becoming opaque and difficult to dissolve later due to crystal precipitation. The subsequent slow cooling (annealing) allows the thermal stress inside the glass to be fully released, preventing the product from breaking during storage or transportation due to excessive internal stress, thus improving the yield.

[0052] Please refer to this carefully. Figures 1 to 6The roasting equipment includes a stepped base 1, from top to bottom, a first roasting furnace 2, a second roasting furnace 3, a third roasting furnace 4, and a fourth roasting furnace 5. The top of each of the first roasting furnace 2, the second roasting furnace 3, the third roasting furnace 4, and the fourth roasting furnace 5 is fixedly connected to an exhaust pipe 6. The inner cavity of each of the first roasting furnace 2, the second roasting furnace 3, the third roasting furnace 4, and the fourth roasting furnace 5 is equipped with a combustion device 7. The materials in the first roasting furnace 2, the second roasting furnace 3, and the third roasting furnace 4 are conveyed by a conveying mechanism 8, and the fourth roasting furnace 5 moves the materials out through a discharge mechanism 9.

[0053] A first hot air inlet duct 10 is installed on the top wall of the first roasting furnace 2 to introduce hot air at a preset temperature into the furnace. A second hot air inlet duct 11 is installed on the top wall of the third roasting furnace 4 to introduce hot air into the furnace, maintaining a low oxygen concentration atmosphere. The first hot air inlet duct 10 and the second hot air inlet duct 11 are connected to a hot air source via air pumps. One or more air inlets 12 are installed on the side wall of the fourth roasting furnace 5. Each air inlet 12 is connected to an induced draft air pump via a solenoid valve and an induced draft pipe. By controlling the opening of different numbers of air inlets 12, the cooling requirements of different rates of rapid cooling and slow cooling in the fourth stage can be met.

[0054] The conveying mechanism 8 includes a feed pipe 802, which is fixedly connected to the outer wall of the first roasting furnace 2. A feed hopper 801 is fixedly connected to the top of the feed pipe 802. A reaction chamber 803 is fixedly connected to the inner cavity of the first roasting furnace 2, the second roasting furnace 3, and the third roasting furnace 4. A conveying pipe 804 extending to the next roasting furnace is fixedly connected to the outer wall of the reaction chamber 803. A conveying motor 805 is installed on the outer wall of the conveying pipe 804, and a conveying shaft 806 is connected to the output end of the conveying motor 805. A storage tank 807 is opened at the top of the reaction chamber 803, and a connecting groove 808 is opened at the bottom of the storage tank 807. The connecting groove 808 communicates with the inner cavity of the conveying pipe 804. A first motor 809 is installed at the top of the first roasting furnace 2, the second roasting furnace 3, and the third roasting furnace 4. A first threaded rod 810 is connected to the output end of a motor 809. A displacement frame 811 is slidably connected to the outer wall of the first threaded rod 810. The displacement frame 811 is slidably connected to the outer wall of the reaction chamber 803. A scraper frame 812 is fixedly connected to one end of the displacement frame 811. A baffle 813 is rotatably connected to the inner cavity of the connecting groove 808. A connecting shaft 814 is fixedly connected to one end of the baffle 813. A spur gear 815 is fixedly connected to one end of the connecting shaft 814. A vertical rod 816 is slidably connected inside the reaction chamber 803. The vertical rod 816 is in contact with the spur gear 815. A spring 817 is connected between the bottom end of the vertical rod 816 and the reaction chamber 803. An extrusion block 818 is slidably connected inside the reaction chamber 803 on one side of the vertical rod 816. One end of the extrusion block 818 extends out of the reaction chamber 803.

[0055] In this embodiment: the material is poured into the feed hopper 801, and enters the storage tank 807 through the feed pipe 802. At this time, the material undergoes a reaction operation in the roasting furnace. After completion, the first motor 809 is started. The first motor 809 drives the first threaded rod 810 to rotate. The rotation of the first threaded rod 810 drives the displacement frame 811 to move. The displacement frame 811 contacts the extrusion block 818, pushing the extrusion block 818 to move. The displacement of the extrusion block 818 pushes the vertical rod 816 to move, compressing the spring 817. The displacement of the vertical rod 816 drives the spur gear 815 to rotate. The rotation of the spur gear 815 drives the connecting shaft 814 to rotate. 14. Rotation drives the baffle 813 to rotate, opening the connecting groove 808. Material enters the conveying pipe 804 through the connecting groove 808. Simultaneously, the displacement frame 811 moves downward, causing the scraper frame 812 to move. The scraper frame 812 moves into the storage tank 807, scraping the inner wall of the storage tank 807 to remove the material adhering to the inner wall. The conveying motor 805 is then started, driving the conveying shaft 806 to rotate. The rotation of the conveying shaft 806 carries the material through the conveying pipe 804 into the next roasting furnace. This design facilitates the transfer of material from one roasting furnace to the next.

[0056] Please refer to this carefully. Figures 7 to 8 The discharge mechanism 9 includes a furnace door 901, which is rotatably connected to the outer wall of the fourth roasting furnace 5. A support plate 902 is fixedly connected to the outer wall of the base 1 on one side of the fourth roasting furnace 5. A second motor 903 is installed on the outer wall of the fourth roasting furnace 5. A second threaded rod 904 is connected to the output end of the second motor 903. A displacement seat 905 is slidably connected to the outer wall of the second threaded rod 904. The displacement seat 905 is slidably connected to the bottom of the inner wall of the fourth roasting furnace 5. A groove 906 is provided at the top of the displacement seat 905. A collection box 907 is slidably connected to the inner wall of the groove 906. A connecting rod 908 is rotatably connected to both sides of the displacement seat 905. A connecting seat 909 is rotatably connected to one end of the connecting rod 908. The connecting seat 909 is fixedly connected to the furnace door 901.

[0057] In this embodiment: the collection box 907 is placed in the groove 906. After the material enters the fourth roasting furnace 5, it falls into the collection box 907 for collection. After the reaction is complete, the second motor 903 is started. The second motor 903 drives the second threaded rod 904 to rotate. The rotation of the second threaded rod 904 drives the displacement seat 905 to move. The displacement of the displacement seat 905 drives the collection box 907 to move. At the same time, the displacement of the displacement seat 905 pushes the furnace door 901 to rotate through the connecting rod 908. The rotation of the furnace door 901 opens the fourth roasting furnace 5, and the displacement seat 905 moves out from the opening of the fourth roasting furnace 5. At this time, the collection box 907 can be taken out from the groove 906. After the new collection box 907 is placed in the groove 906, the displacement seat 905 moves into the fourth roasting furnace 5. At this time, the furnace door 901 automatically closes the fourth roasting furnace 5, so that when the fourth roasting furnace 5 is opened, the collection box 907 can be automatically moved out, making it convenient to take out the material from the fourth roasting furnace 5.

[0058] Please refer to this carefully. Figures 1 to 6 The displacement frame 811 is n-shaped and has a first threaded hole on the outer wall of the top end, which matches the first threaded rod 810.

[0059] In this embodiment: the first motor 809 is started, the first motor 809 drives the first threaded rod 810 to rotate, and the rotation of the first threaded rod 810 drives the displacement frame 811 to move.

[0060] Please refer to this carefully. Figures 1 to 6 The outer wall of the scraper 812 is in contact with the inner wall of the storage tank 807.

[0061] In this embodiment: the displacement frame 811 moves downward, causing the scraper frame 812 to move. The scraper frame 812 moves into the storage tank 807 and scrapes the inner wall of the storage tank 807 to remove the material adhering to the inner wall of the storage tank 807.

[0062] Please refer to this carefully. Figures 1 to 6 The end of the extrusion block 818 extending out of the reaction chamber 803 is provided with an inclined surface, which is located below the displacement frame 811. The outer wall of the vertical rod 816 is provided with an inclined groove, and the extrusion block 818 is in contact with the inclined groove.

[0063] In this embodiment: the rotation of the first threaded rod 810 drives the displacement frame 811 to move, the displacement frame 811 moves and comes into contact with the extrusion block 818, pushing the extrusion block 818 to move, the extrusion block 818 moves and pushes the vertical rod 816 to move, causing compression on the spring 817.

[0064] Please refer to this carefully. Figures 1 to 6 The outer wall of the vertical rod 816 is provided with a toothed groove, which meshes with the spur gear 815.

[0065] In this embodiment: the vertical rod 816 displacement drives the spur gear 815 to rotate, the rotation of the spur gear 815 drives the connecting shaft 814 to rotate, the rotation of the connecting shaft 814 drives the baffle 813 to rotate, and the rotation of the baffle 813 opens the connecting groove 808.

[0066] Please refer to this carefully. Figures 7 to 8 The outer wall of the displacement seat 905 is provided with a second threaded hole, which matches the second threaded rod 904. The inner wall of the groove 906 fits against the outer wall of the collection box 907.

[0067] In this embodiment: the collection box 907 is placed in the groove 906. After the material enters the fourth roasting furnace 5, the material falls into the collection box 907 for collection. The second motor 903 drives the second threaded rod 904 to rotate, and the rotation of the second threaded rod 904 drives the displacement seat 905 to move. Example 2

[0068] This embodiment provides a preparation process for solid sodium silicate with a modulus of 2.0, specifically including the following steps:

[0069] Step 1: Raw material ratio: Accurately weigh 80-mesh quartz sand (SiO2 content 98.6%) and soda ash (Na2CO3 content 98.8%), and accurately mix them according to the SiO2 / Na2O molar ratio of 2.0.

[0070] Step 2: Mixing and homogenization: Put the prepared raw materials into a high-efficiency mixer and mix for 30 minutes. Then, compress the mixed powder into tablets to form uniform raw material particles with a particle size of 8-10mm.

[0071] Step 3: Segmented temperature-controlled roasting:

[0072] Phase 1: The temperature is programmed to rise from room temperature to 200°C at a rate of 8°C / min, with the material held for 20 minutes; an airflow of 50°C and a flow rate of 3 Nm³ is introduced. 3 Hot air per kg of material.

[0073] Second stage: Increase the temperature from 200℃ to 800℃ at a rate of 10℃ / min, and hold at that temperature for 15 minutes to maintain a weak oxidizing atmosphere.

[0074] The third stage involves rapidly increasing the temperature from 800℃ to 1250℃ at a rate of 10℃ / min, holding this temperature for 30 minutes to maintain a stable and calm melting environment.

[0075] Fourth stage: Starting from 1250℃, the temperature is programmed to cool down. The rapid cooling section (1250℃ to 1000℃) is cooled at a rate of 15℃ / min; the slow cooling section (1000℃ to 800℃) is cooled at a rate of 10℃ / min.

[0076] Step 4: Post-processing: The block solid glass, cooled to below 800℃, is directly packaged as a block product.

[0077] The production equipment used in the preparation process is the same as in Example 1, and will not be described again here. Example 3

[0078] This embodiment provides a preparation process for solid sodium silicate with a modulus of 3.2, specifically including the following steps:

[0079] Step 1: Raw material ratio: Accurately weigh 200-mesh quartz sand (SiO2 content 98.8%) and soda ash (Na2CO3 content 98.5%), and accurately mix them according to the SiO2 / Na2O molar ratio of 3.2.

[0080] Step 2: Mixing and homogenization: Put the prepared raw materials into a high-efficiency mixer and mix for 50 minutes. Then, granulate the mixed powder into uniform raw material particles with a particle size of 3-5mm using a disc granulator.

[0081] Step 3: Segmented temperature-controlled roasting:

[0082] Phase 1: The temperature is programmed to rise from room temperature to 600°C at a rate of 3°C / min, with the material held for 40 minutes; an airflow of 1Nm³ at 100°C is introduced. 3 Hot air per kg of material.

[0083] Second stage: Increase the temperature from 600℃ to 900℃ at a rate of 5℃ / min, and hold at that temperature for 30 minutes to maintain a weak oxidizing atmosphere.

[0084] The third stage involves rapidly increasing the temperature from 900℃ to 1350℃ at a rate of 15℃ / min, holding this temperature for 60 minutes to maintain a stable and calm melting environment.

[0085] Fourth stage: Starting from 1350℃, the temperature is programmed to cool down. The rapid cooling section (1350℃ to 1000℃) is cooled at a rate of 25℃ / min; the slow cooling section (1000℃ to 800℃) is cooled at a rate of 5℃ / min.

[0086] Step 4: Post-processing: The solid glass, cooled to below 800°C, is placed in a pressure melting tank and heated with steam to dissolve it, thus preparing liquid sodium silicate.

[0087] The production equipment used in the preparation process is the same as in Example 1, and will not be described again here.

[0088] Comparative Example 1

[0089] This comparative example uses a traditional one-step roasting process in a reverberatory furnace.

[0090] Step 1: Raw material ratio: Same as in Example 1.

[0091] Step 2: Mixing and homogenization: Same as in Example 1.

[0092] Step 3: Calcination: The raw material pellets are fed into a reverberatory furnace and heated directly from room temperature to 1250°C at a rate of 10°C / min, and held at this temperature for 60 minutes. After the reaction is complete, the heat source is turned off, and the material is allowed to cool naturally to room temperature in the furnace at an average rate of about 5-15°C / min.

[0093] Step 4: Post-processing: The cooled solid is crushed to obtain an irregular blocky product that is slightly yellow, opaque and contains unreacted nuclei (sand cores).

[0094] Comparative Example 2

[0095] This comparative example is used to demonstrate the unique necessity of the "controllable cooling section" of the present invention.

[0096] Step 1: Raw material ratio: Same as in Example 1.

[0097] Step 2: Mixing and homogenization: Same as in Example 1.

[0098] Step 3: Calcination: The process parameters for the first, second, and third stages are exactly the same as those in Example 1.

[0099] Step 4: Cooling: After the third stage of reaction is completed (melt temperature is 1250℃), the cooling procedure of this invention is not followed. Instead, the material is naturally cooled to room temperature along with the furnace, mimicking the traditional process.

[0100] Step 5: Post-processing: Same as in Example 1, crush and sieve the cooled solid.

[0101] Product performance testing and data analysis

[0102] The performance of the products obtained from all the above embodiments and comparative examples was tested, and the test results are shown in Table 1.

[0103] Detection method:

[0104] 1. Conversion rate: The content of unreacted quartz sand in the product was determined by the hydrofluoric acid loss method, and the conversion rate was calculated.

[0105] 2. Whiteness / Transparency: Solid products are measured using a whiteness meter; liquid products are measured using a spectrophotometer at a wavelength of 660nm for transmittance (%).

[0106] 3. Internal stress: The stress level inside the glass is observed using a polarized light stress meter (level 1-5, the higher the level, the greater the stress).

[0107] 4. Dissolution rate: Weigh (10.00±0.01)g of granular product (2-5mm) and put it into a beaker containing 90mL of deionized water. Stir at a fixed speed in an 80℃ constant temperature water bath and record the time required for complete dissolution.

[0108] 5. Product form: Visually inspect the uniformity, color, and transparency of the vitreous or solution.

[0109] Table 1. Comparison of Product Performance Test Results

[0110]

[0111] In summary, all the indicators of the embodiments are significantly better than those of Comparative Example 1 (conventional process), demonstrating the superiority of the overall process of the present invention. The comparison between Comparative Example 2 and Example 1 is particularly crucial: the only difference between the two is the cooling method. The product of Comparative Example 2 has low whiteness, high internal stress, and opalescence (signs of microcrystal precipitation), which directly proves that the "rapid cooling + slow cooling" process in the present invention plays a decisive and irreplaceable role in obtaining high whiteness, low internal stress, and crystal-free glass quality.

[0112] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A process for preparing solid sodium silicate based on segmented temperature-controlled calcination, characterized in that, The specific steps are as follows: Step 1: Raw material ratio: Accurately weigh the quartz sand and soda ash, and precisely mix them according to a SiO2 to Na2O molar ratio of 2.0-3.3; wherein the quartz sand has an SiO2 content ≥98.5% and a particle size of 80-200 mesh, and the soda ash has a Na2CO3 content ≥98.5%; Step 2: Homogenization: Put the raw materials prepared in Step 1 into the mixer and mix for no less than 30 minutes to ensure that the material composition is highly uniform. Then, press the mixed powder into tablets or granulate it into uniform raw material particles with a particle size of 3-10mm. Step 3: Segmented temperature-controlled roasting. The raw material pretreated in Step 2 is fed into a roasting equipment with segmented precise temperature control function for segmented roasting reaction. Step 4: Post-processing. The solid glass, cooled to below 800°C, is then processed to obtain block, granular, or liquid sodium silicate products. Step 3, the segmented temperature-controlled calcination, includes the following stages: Phase 1: Low-temperature dehydration and preheating section; temperature is programmed to rise from room temperature to 200℃-600℃; a heating rate of 3-8℃ / min is used to ensure sufficient evaporation of physical water without causing material splashing; the total residence time of the material in this temperature zone is 20-40 minutes; the inlet temperature is 50-100℃ and the air volume is 1-3 Nm³. 3 Hot air per kg of material is used to carry away moisture and expel it. Second stage: Medium-temperature reaction initiation section; heat to 800℃-900℃; use a heating rate of 5-10℃ / min; after reaching the upper limit of the target temperature, hold at this temperature for 15-30 minutes; maintain a weak oxidizing atmosphere to ensure that organic impurities are fully decomposed; The third stage: high-temperature full reaction zone; rapidly raise the temperature to 1250℃-1350℃; use a heating rate of 10-15℃ / min to reduce the volatilization and heat loss of components at high temperatures, and promote the rapid melting reaction to reduce the influence of volume effect; maintain this reaction temperature zone for 30-60 minutes to maintain a stable and calm melting environment, and avoid forced airflow agitation; Fourth stage: Controlled cooling section; Temperature range: Cooling from the reaction temperature of the third stage to below 800℃; Cooling rate: Two-stage programmable cooling; First stage, rapid cooling section: Rapid cooling from the discharge temperature to 1000℃, with the rate controlled at 15-25℃ / min; This stage is crucial for suppressing crystal precipitation; Second stage, slow cooling section: Slow cooling from 1000℃ to below 800℃, with the rate controlled at 5-10℃ / min.

2. The solid sodium silicate preparation process based on segmented temperature-controlled calcination according to claim 1, characterized in that, The roasting equipment described in step three includes a stepped base (1), and the base (1) is provided with a first roasting furnace (2), a second roasting furnace (3), a third roasting furnace (4) and a fourth roasting furnace (5) arranged from top to bottom. The top of the first roasting furnace (2), the third roasting furnace (4) and the fourth roasting furnace (5) are all fixedly connected with exhaust pipes (6). The inner cavity of the first roasting furnace (2), the second roasting furnace (3), the third roasting furnace (4) and the fourth roasting furnace (5) is equipped with combustion equipment (7). The materials in the first roasting furnace (2), the second roasting furnace (3) and the third roasting furnace (4) are all conveyed by a conveying mechanism (8). The fourth roasting furnace (5) moves the materials out through a discharge mechanism (9). A first hot air inlet pipe (10) is provided on the first roasting furnace (2), and a second hot air inlet pipe (11) is provided on the third roasting furnace (4). The first hot air inlet pipe (10) and the second hot air inlet pipe (11) are respectively connected to a hot air source through an air pump. One or more air inlets (12) are provided on the fourth roasting furnace (5), and each of the air inlets (12) is connected to an air pump through a solenoid valve and an air duct.

3. The solid sodium silicate preparation process based on segmented temperature-controlled calcination according to claim 2, characterized in that, The conveying mechanism (8) includes a feed pipe (802), which is fixedly connected to the outer wall of the first roasting furnace (2). A feed hopper (801) is fixedly connected to the top end of the feed pipe (802). A reaction chamber (803) is fixedly connected to the inner cavity of the first roasting furnace (2), the second roasting furnace (3), and the third roasting furnace (4). A conveying pipe (804) extending to the next roasting furnace is fixedly connected to the outer wall of the reaction chamber (803). A conveyor motor (805) is installed on the outer wall of the reaction chamber (803). The output end of the conveyor motor (805) is connected to a conveyor shaft (806). A storage tank (807) is opened at the top of the reaction chamber (803). A connecting groove (808) is opened at the bottom of the storage tank (807). The connecting groove (808) is connected to the inner cavity of the conveying pipe (804). A first motor (809) is installed at the top of the first roasting furnace (2), the second roasting furnace (3), and the third roasting furnace (4). The output end of the machine (809) is connected to a first threaded rod (810). A displacement frame (811) is slidably connected to the outer wall of the first threaded rod (810). The displacement frame (811) is slidably connected to the outer wall of the reaction chamber (803). A scraper frame (812) is fixedly connected to one end of the displacement frame (811). A baffle (813) is rotatably connected to the inner cavity of the connecting groove (808). A connecting shaft (814) is fixedly connected to one end of the baffle (813). One end of the reaction chamber (803) is fixedly connected to a spur gear (815). A vertical rod (816) is slidably connected inside the reaction chamber (803). The vertical rod (816) is in contact with the spur gear (815). A spring (817) is connected between the bottom end of the vertical rod (816) and the reaction chamber (803). An extrusion block (818) is slidably connected inside the reaction chamber (803) on one side of the vertical rod (816). One end of the extrusion block (818) extends out of the reaction chamber (803).

4. The solid sodium silicate preparation process based on segmented temperature-controlled calcination according to claim 3, characterized in that, The discharge mechanism (9) includes a furnace door (901), which is rotatably connected to the outer wall of the fourth roasting furnace (5). A support plate (902) is fixedly connected to the outer wall of the base (1) on one side of the fourth roasting furnace (5). A second motor (903) is installed on the outer wall of the fourth roasting furnace (5). A second threaded rod (904) is connected to the output end of the second motor (903). A displacement device is slidably connected to the outer wall of the second threaded rod (904). The displacement seat (905) is slidably connected to the bottom of the inner wall of the fourth roasting furnace (5). The top of the displacement seat (905) is provided with a groove (906). A collection box (907) is slidably connected to the inner wall of the groove (906). A connecting rod (908) is rotatably connected to both sides of the displacement seat (905). A connecting seat (909) is rotatably connected to one end of the connecting rod (908). The connecting seat (909) is fixedly connected to the furnace door (901).

5. The solid sodium silicate preparation process based on segmented temperature-controlled calcination according to claim 3, characterized in that, The displacement frame (811) is n-shaped and has a first threaded hole on the outer wall of the top end, which matches the first threaded rod (810); the outer wall of the scraper frame (812) is in contact with the inner wall of the storage tank (807).

6. The solid sodium silicate preparation process based on segmented temperature-controlled calcination according to claim 3, characterized in that, The extrusion block (818) extends out of the reaction chamber (803) and is provided with an inclined surface, which is located below the displacement frame (811).

7. The solid sodium silicate preparation process based on segmented temperature-controlled calcination according to claim 3, characterized in that, The outer wall of the vertical rod (816) is provided with an inclined groove, and the extrusion block (818) is in contact with the inclined groove.

8. The solid sodium silicate preparation process based on segmented temperature-controlled calcination according to claim 3, characterized in that, The outer wall of the vertical rod (816) is provided with a toothed groove, which meshes with the spur gear (815).

9. The solid sodium silicate preparation process based on segmented temperature-controlled calcination according to claim 4, characterized in that, The outer wall of the displacement seat (905) is provided with a second threaded hole, which matches the second threaded rod (904), and the inner wall of the groove (906) is in contact with the outer wall of the collection box (907).

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