Method for separating silicon-containing impurities from quicklime

Abstract

The invention discloses a method for separating silicon-containing impurities from re-quicklime, and relates to the technical field of separation of silicon-containing impurities from re-quicklime, and the method comprises the following steps: S1, mixing calcined re-quicklime with water according to a mass ratio of 1: (1-3) to form re-quicklime slurry, and reacting calcium oxide in the re-quicklime with water to generate calcium hydroxide; s2, the reaction is maintained for 30-90 minutes under the stirring condition, and the reaction temperature is controlled to be 40-80 DEG C; s3, standing and settling after stirring is stopped, so that calcium hydroxide with lower density floats upwards, and silicon-containing impurities with higher density, including silicon dioxide and calcium silicate, are settled; s4, separating the upper-layer calcium hydroxide slurry from the lower-layer silicon-containing precipitate by adopting a gravity separation, scraping or mechanical filtration mode to obtain a re-quicklime product after silicon removal, compared with a traditional acid pickling or single screening process, the method does not introduce an acidic medium, does not need high-energy-consumption equipment, is simple in process and environment-friendly, and is suitable for continuous industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of separating silicon-containing impurities from regenerated lime, in particular to a method for separating silicon-containing impurities from regenerated lime. BACKGROUND

[0002] The pulp and paper industry is a traditional industry with high resource and energy consumption, and the alkali recovery system plays a key role in the entire production process. Pulping lime mud is a byproduct generated after evaporation of papermaking waste liquid through causticization reaction, and its main component is calcium carbonate (CaCO3), and it also contains a certain amount of silicon dioxide (SiO2), calcium silicate (CaSiO3), magnesium oxide (MgO) and other impurities. The traditional alkali recovery process usually generates regenerated lime (CaO) by high-temperature calcination of lime mud, which is then used in the causticization reaction to recover sodium hydroxide (NaOH), forming an alkali recycling system. However, in the pulping process of grass and straw materials, the raw materials contain a high amount of silicon, resulting in a SiO2 content in lime mud as high as 8% to 15%. These silicon components are prone to react with CaO to form low-melting silicate phases during calcination, resulting in a large amount of silicon-containing impurities in regenerated lime, which seriously affects its chemical activity and reuse performance.

[0003] Currently, the main methods for removing silicon in the industry include chemical pickling, wet extraction, physical screening, and electrodialysis. Although the acid pickling method can dissolve part of the silicate, it can cause equipment corrosion, liquid waste acid discharge, and secondary pollution. The wet extraction and electrodialysis methods are complex in equipment, high in energy consumption, and expensive in cost, making it difficult to adapt to the continuous production conditions of small and medium-sized paper mills. Simply relying on physical classification or screening methods can only remove large particles of calcium silicate and has little effect on fine SiO2 impurities. In addition, these methods generally lack real-time control and quantitative monitoring of the reaction process, and the silicon removal effect is unstable, often resulting in "insufficient or excessive silicon removal" phenomenon, which leads to large fluctuations in the activity of regenerated lime, reduces the CaO content, and even affects the balance of the entire alkali recovery system. SUMMARY

[0004] The present application provides a method for separating silicon-containing impurities from regenerated lime, which can effectively solve the problems raised in the background art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a method for separating silicon-containing impurities from regenerated lime, comprising the following steps: S1, mixing the regenerated lime obtained by calcination with water at a mass ratio of 1:(1-3) to form a regenerated lime slurry, and allowing the calcium oxide in the regenerated lime to react with water to generate calcium hydroxide; S2, maintaining the reaction under stirring for 30-90 minutes, and controlling the reaction temperature at 40-80℃; S3, after stopping stirring, standing and settling, the calcium hydroxide with lower density floats up, and the silicon-containing impurities, including silicon dioxide and calcium silicate, with higher density settle down; S4, the upper layer calcium hydroxide slurry and the lower layer silicon-containing precipitate are separated by gravity separation, scraping or mechanical filtration to obtain the regenerated lime product after silicon removal.

[0006] According to the above technical solution, the mixing reaction of the regenerated lime and water in S1 is a controlled hydration reaction. In order to completely hydrate the calcium oxide and prevent local overheating, the regenerated lime is crushed to a particle size of 0.2-1.0 mm before the reaction, the water addition rate is controlled to be 0.5-1.0 L / min, and a mechanical stirrer is used to continuously stir at a speed of 100-300 rpm for 30-90 minutes. By stirring, a uniform lime slurry is formed, and the reaction temperature is maintained at 40-80°C.

[0007] According to the above technical solution, in S3, the closed settling tank is first naturally stationary for 2-6 hours. After the calcium hydroxide slurry and the silicon-containing precipitate form a clear interface, the high-density precipitate in the lower layer is slowly discharged through the bottom discharge valve. Then, the upper layer slurry is introduced into a secondary settling tank, and residual fine particles are removed by slow cyclonic separation. Fine silicate solids are further removed by a filtration device. Before filtration, 0.01-0.05% of a cationic flocculant can be added to promote particle coagulation and increase the separation rate. The upper layer liquid after three-stage separation is a high-purity regenerated lime slurry, which can be dried to obtain regenerated lime with a CaO content of more than 90%.

[0008] According to the above technical solution, after the silicon-containing precipitate in S4 is separated, it can be further dried and sieved to prepare a silicon-containing byproduct, realizing resource utilization. Specifically, the obtained precipitate is centrifuged and dewatered, then dried at 80-120°C for 3-6 hours to reduce the moisture content to less than 5%, and then sieved by a screening machine to a powder form with a particle size of less than 1 mm.

[0009] According to the above technical solution, in S1, to improve the separation effect of silicon-containing impurities in the regenerated lime, the regenerated lime is pre-classified and particle size controlled before the reaction step. The regenerated lime is sieved by a vibrating screen before entering the reaction device, and the screen aperture is set to 0.2-1.5 mm. After the sieved regenerated lime enters the reaction tank, water is added in pulses. Each time, the water volume accounts for 10%-15% of the total water volume, and the interval time is 2-5 minutes.

[0010] According to the technical scheme, the S3 uses a dynamic fluidization separation device instead of a traditional static settling structure in a separation step to accelerate the relative migration speed of the silicon-containing impurities and the calcium hydroxide; The device includes a cylindrical reaction tank, a bottom gas distribution plate, and a circulating pump system. By introducing micro-bubbles or low-speed stirring to form a light fluidization state in the separation stage, the calcium hydroxide particles with a smaller specific gravity rise to the liquid surface, and the silicon-containing impurities with a specific gravity greater than 2.5 g / cm³ settle to the bottom. During the separation process, the micro-bubble flow rate can be maintained at 0.2-0.5 m³ / h to maintain the stability of the stratification interface; When the stratification is stable, the bottom slag discharge port is opened to discharge the silicon-containing sediment, and the upper liquid enters the liquid storage tank through the overflow pipe; Using dynamic separation instead of static separation can shorten the separation time from 2-6 hours to 20-40 minutes while maintaining separation accuracy.

[0011] According to the technical scheme, the reaction of regenerated lime and water in S1 is carried out using a multi-stage hydration control system, which is divided into a primary reaction stage and a strengthening reaction stage. In the primary stage, the reaction temperature is controlled at 40-50°C to allow calcium oxide to slowly hydrate to form calcium hydroxide; in the strengthening stage, the system temperature is raised to 70-80°C and stirring is continued for 20-40 minutes to accelerate the hydration reaction and promote density stratification.

[0012] According to the technical scheme, an interface optical detection system is introduced in the S4 stratification stage to identify the stratification state in real time. The detection system includes a laser transmission module, a reflected light receiving module, and an image recognition algorithm. The interface height between the upper calcium hydroxide slurry and the lower silicon-containing sediment layer is determined by monitoring the change in scattered light intensity in the slurry. When the interface is stable, the slag discharge valve is automatically triggered.

[0013] According to the technical scheme, in the stratification stage, the interface position between the calcium hydroxide slurry and the silicon-containing sediment layer is calculated by an optical detection module and a computer vision algorithm. The detection module includes a high-resolution camera and a laser illumination device to capture the scattered light image inside the slurry. The system calculates the light intensity gradient using the gray scale distribution function G(x,y) and identifies the interface contour line using an edge detection algorithm such as Sobel or Canny operator. The interface position height h is calculated by the following formula:

[0014] Where h is the pixel position corresponding to the maximum change in light intensity, which is converted to the actual height and used to control the opening time of the slag discharge valve. When the interface height change rate When the speed is <0.5 mm / min, the system determines that the layering is stable and automatically enters the slag discharge stage.

[0015] According to the above technical solution, after the separation is completed, the silicon removal effect and the purity of regenerated lime are evaluated in real time through a calculation model; The silicon removal efficiency η is calculated according to the following formula:

[0016] Where C0 is the mass fraction of silicon element in the regenerated lime sample before the reaction, and C1 is the mass fraction of silicon element in the upper layer product after the separation; The purity of calcium oxide in regenerated lime Indirectly calculated by the conductivity method, satisfying the following approximate relationship:

[0017] Where is the conductivity of the standard solution, is the conductivity of the test sample, and k is a constant obtained through calibration; The system automatically collects and and outputs η and values in real time. When η≥85% and ≥90%, it is determined that the separation is qualified; This calculation model realizes the quantitative evaluation and quality closed-loop control of the silicon removal process, providing data support for the industrial process.

[0018] Compared with the prior art, the beneficial effects of the present invention: The structure of the present invention is scientific and reasonable, safe and convenient to use. A method for separating silicon-containing impurities from regenerated lime provided by the present invention can, on the basis of obtaining regenerated lime by conventional calcination, realize the efficient removal of silicon-containing impurities in regenerated lime through the combined use of controlled hydration reaction, density layering sedimentation and mechanical filtration. Compared with the traditional pickling or single screening process, this method does not introduce acidic media, does not require high-energy-consuming equipment, has a simple process and is environmentally friendly, and is suitable for continuous industrial production; The present invention introduces a multi-stage hydration control system in the reaction stage. By adjusting the reaction temperature, water addition rate and stirring intensity in stages, calcium oxide can be fully hydrated to avoid local overheating, thereby preventing the surface calcification of calcium silicate and improving the production rate of calcium hydroxide. In the separation stage, a process combining a dynamic fluidization structure with gravity sedimentation, mechanical separation and filtration is adopted, enabling the rapid and stable separation of the upper layer of calcium hydroxide and the lower layer of silicon-containing sediment, with significantly improved efficiency.

[0019] In terms of monitoring and control, the application realizes automatic identification and position determination of the layered interface through optical detection and computer vision algorithm, can detect interface changes in real time, automatically triggers the deslagging operation, reduces human error, improves the controllability and repeatability of the desiliconization process, and dynamically evaluates the desiliconization rate and calcium oxide purity by combining data models, so that the production process is changed from manual experience control to quantitative and intelligent control, which significantly improves the product stability and process reliability.

[0020] The method not only improves the chemical properties and reaction activity of the regenerated lime, but also realizes the stable operation of the alkali recovery system, has the advantages of low energy consumption, low emission, high purity and sustainable utilization, and is suitable for better popularization and use. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, together with the embodiments of the application, to explain the application, and do not constitute a limitation on the application.

[0022] In the drawings: Figure 1 is a schematic diagram of the method steps of the application. DETAILED DESCRIPTION

[0023] The preferred embodiments of the application will be described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the application, and do not limit the application.

[0024] Embodiment: As shown in the application, a method for separating silicon-containing impurities from regenerated lime is provided, comprising the following steps: Figure 1 S1, mix the regenerated lime obtained by calcination with water in a mass ratio of 1:(1-3) to form a regenerated lime slurry, and let the calcium oxide in the regenerated lime react with water to form calcium hydroxide; S2, maintain the reaction under stirring for 30-90 minutes, and control the reaction temperature at 40-80 DEG C; S3, after stopping stirring, let it stand and settle, so that the calcium hydroxide with lower density floats up, and the silicon-containing impurities including silicon dioxide and calcium silicate settle down; S4, separate the upper calcium hydroxide slurry from the lower silicon-containing precipitate by gravity separation, scraping or mechanical filtration to obtain the regenerated lime product after desiliconization.

[0025] ​According to the above technical scheme, the mixing reaction of the regenerated lime and water in S1 is a controlled hydration reaction. In order to completely hydrate the calcium oxide and prevent local overheating, the regenerated lime is crushed to a particle size of 0.2-1.0 mm before the reaction, the water addition rate is controlled to be 0.5-1.0 L / min, and a mechanical stirrer is used to continuously stir at a speed of 100-300 rpm for 30-90 minutes. By stirring, a uniform lime slurry is formed in a suspended state, and the reaction temperature is maintained at 40-80°C to avoid overheating of the reaction, which causes the surface of the silicon dioxide to be calcified, making it difficult to separate. During the reaction, the water temperature can be adjusted by an external circulating cooling device according to the system temperature to ensure stable system temperature, so that the calcium oxide is fully converted into calcium hydroxide to form a low-density floating component. By controlling the particle size and stirring speed, the Ca(OH)2 particles are uniformly dispersed and do not adhere to the surface of the calcium silicate, improving the separation effect after the reaction and significantly improving the separation efficiency.

[0026] According to the above technical scheme, the separation method used after the static separation in S3 is a combination of "gravity settling - mechanical separation - filtration". After the reaction is completed, the calcium hydroxide slurry is first naturally static in a closed settling tank for 2-6 hours. After the calcium hydroxide slurry and the silicon-containing precipitate form a clear interface, the high-density sediment is slowly discharged through the bottom discharge valve. Then the upper slurry is introduced into a secondary settling tank, and the residual fine particles are removed by slow cyclonic separation. A filtration device with a filtration accuracy of 100-200 μm is used to further remove fine silicate solids. Before filtration, 0.01-0.05% of a cationic flocculating agent can be added to promote particle coagulation and improve separation rate. The upper liquid after three-stage separation is a high-purity regenerated lime slurry, which can be dried to obtain regenerated lime with a CaO content of more than 90%. Through the above separation combination steps, the desiliconization rate is increased by about 15%-25%, and the problem of incomplete separation caused by single gravity settling is avoided.

[0027] According to the above technical scheme, after the reaction, the silicon-containing precipitate can be further dried and sieved to prepare a silicon-containing byproduct for resource utilization. Specifically, the obtained sediment is centrifuged and then dried at 80-120°C for 3-6 hours to reduce the water content to less than 5%. Then, the sediment is sieved to a powder with a particle size of less than 1 mm. Chemical composition analysis shows that the main components are silicon dioxide (SiO2) and calcium silicate (CaSiO3), and the silicon content is greater than 70%. The sediment can be directly used as a cement clinker or a building material filler. This byproduct recovery process can simultaneously recover calcium ions from the regenerated limewater phase, reducing the alkalinity of the wastewater. This measure achieves silicon removal while creating a byproduct reuse pathway, further reducing waste emissions and improving the overall resource utilization rate and economic benefits of the process.

[0028] According to the above technical solution, in order to improve the separation effect of silicon-containing impurities in recycled lime in S1, the recycled lime is pre-classified and its particle size is controlled before the reaction step. Before entering the reaction device, the recycled lime is screened by a vibrating screen with a screen aperture of 0.2 to 1.5 mm to remove large particles of incompletely calcined residue and fine powder, so as to ensure the uniformity of particles in the reaction system. After the recycled lime is screened, it enters the reaction tank and the reaction water is added gradually in a pulse water addition method. Each water addition accounts for 10% to 15% of the total water addition volume, and the interval is 2 to 5 minutes. The segmented water addition method can effectively reduce the local intense heat release phenomenon, prevent the formation of a coating layer that hinders the hydration reaction, and allow the calcium oxide to react fully. An optional built-in propeller-type agitator can be installed in the reaction system to achieve uniform suspension of materials in an axial flow manner. After the reaction, the temperature is automatically reduced to below 40°C by a temperature control system to prevent recrystallization of Ca(OH)2 crystals. Through the above measures, the slurry layer interface after the reaction can be made clearer, the desiliconization rate can be increased by about 10% to 15%, and the agglomeration of calcium silicate in recycled lime can be reduced.

[0029] According to the above technical solution, S3 uses a dynamic fluidized separation device instead of the traditional static sedimentation structure in the separation step to accelerate the relative migration rate of silicon-containing impurities and calcium hydroxide. The device includes a cylindrical reaction vessel, a bottom gas distribution plate, and a circulation pump system. By introducing microbubbles or low-speed stirring during the separation stage to create a slightly fluidized state, the calcium hydroxide particles with a smaller specific gravity rise to the liquid surface, while silicon-containing impurities with a specific gravity greater than 2.5 g / cm³ settle to the bottom. During the separation process, the microbubble introduction rate can be maintained at 0.2–0.5 m³ / h to maintain the stability of the stratification interface. After the stratification is stable, the bottom slag discharge port is opened to discharge the silica-containing sediment, and the upper liquid enters the storage tank through the overflow pipe. By adopting dynamic separation instead of static setting, the separation time can be shortened from the original 2–6 hours to 20–40 minutes while maintaining the separation accuracy, which greatly improves the processing efficiency. This method can be matched with continuous production lines and has industrial adaptability.

[0030] According to the above technical solution, the reaction between recycled lime and water in S1 is carried out using a multi-stage hydration control system, which is divided into a primary reaction stage and an enhanced reaction stage: In the initial stage, the reaction temperature is controlled at 40-50℃ to allow calcium oxide to slowly hydrate and generate calcium hydroxide; in the intensification stage, the system temperature is raised to 70-80℃ and stirred continuously for 20-40 minutes to accelerate the hydration reaction and promote density stratification. The two stages are switched automatically by a temperature control program to prevent local high temperatures from causing calcium silicate surface calcification; Immediately after the strengthening stage, allow the mixture to stand for at least 60 minutes to obtain a clear interface between the upper calcium hydroxide slurry and the lower silica-containing deposit. This multi-stage hydration reaction control system can increase the calcium oxide conversion rate by more than 5% and the silicon removal rate by about 20%, achieving precise reaction control and automated operation.

[0031] According to the above technical solution, in the S4 layering stage, an interface optical detection system is introduced to identify the layering state in real time. The detection system includes a laser transmission module, a reflected light receiving module, and an image recognition algorithm. The interface height between the upper calcium hydroxide slurry and the lower silicon-containing deposition layer is determined by monitoring the change in the intensity of scattered light in the slurry. When the interface is stable, the slag discharge valve is automatically triggered. The system can automatically calculate the deposition rate, interface thickness, and reaction completion based on the light intensity distribution. Compared with the traditional manual observation method, the detection system has a resolution of ±1mm, which can significantly improve the separation accuracy and reliability of continuous production, and ensure the automation and controllability of silicon removal operation.

[0032] According to the above technical solution, in the layering stage, the interface position between the calcium hydroxide slurry and the silicon-containing deposition layer is calculated by an optical detection module and a computer vision algorithm; the detection module includes a high-resolution camera and a laser illumination device to acquire images of scattered light inside the slurry; The system uses the gray-level distribution function G(x,y) to calculate the light intensity gradient and identifies the interface contour lines using edge detection algorithms (such as the Sobel or Canny operator). The interface position height h is calculated by the following formula:

[0033] Where h is the pixel position corresponding to the point of maximum light intensity change, which is converted into actual height and used to control the opening time of the slag discharge valve; When the interface height changes rate When the flow rate is less than 0.5 mm / min, the system determines that the stratification is stable and automatically enters the slag discharge stage; This calculation method can monitor the position of the sedimentation interface in real time without disturbing the reaction system, reducing the error to ±1mm compared to manual observation, and significantly improving the separation control accuracy.

[0034] According to the above technical solution, after separation is completed, the desiliconization effect and the purity of the recycled lime are evaluated in real time through a calculation model; The silicon removal efficiency η is calculated by the following formula:

[0035] where C0 is the mass fraction of silicon element in the regenerated lime sample before the reaction, and C1 is the mass fraction of silicon element in the upper product after separation; The purity of calcium oxide in regenerated lime is indirectly calculated by the conductivity method and satisfies the following approximate relationship:

[0036] where is the conductivity of the standard solution, is the conductivity of the test sample, and k is a constant obtained by calibration; The system automatically collects and and outputs η and values in real time. When η≥85% and ≥90%, it is determined that the separation is qualified; This calculation model realizes the quantitative evaluation and quality closed-loop control of the silicon removal process, providing data support for the industrial process.

[0037] Finally, it should be noted that the above are only preferred examples of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for separating silicon-containing impurities from recycled lime, characterized in that: Includes the following steps: S1. The calcined recycled lime is mixed with water at a mass ratio of 1:(1-3) to form a recycled lime slurry, and the calcium oxide in the recycled lime reacts with the water to generate calcium hydroxide. S2. Maintain the reaction under stirring for 30-90 minutes, and control the reaction temperature at 40-80℃; S3. After stopping stirring, let it stand and settle, so that the less dense calcium hydroxide floats to the top, while the denser silicon-containing impurities, including silicon dioxide and calcium silicate, settle. S4. The upper layer of calcium hydroxide slurry and the lower layer of silicon-containing precipitate are separated by gravity separation, scraping or mechanical filtration to obtain the desiliconized recycled lime product.

2. The method for separating silicon-containing impurities from recycled lime according to claim 1, characterized in that, The mixing reaction of recycled lime and water in S1 is a controlled hydration reaction. In order to ensure complete hydration of calcium oxide and prevent local overheating, the recycled lime is crushed to a particle size of 0.2-1.0 mm before the reaction. The water addition rate is controlled at 0.5-1.0 L / min, and a mechanical stirrer is used to continuously stir at a speed of 100-300 rpm for 30-90 minutes. A uniformly suspended lime slurry is formed by stirring, and the reaction temperature is maintained between 40-80℃.

3. The method for separating silicon-containing impurities from recycled lime according to claim 1, characterized in that, S3 is first allowed to stand naturally in a closed settling tank for 2-6 hours. After a clear interface is formed between the calcium hydroxide slurry floating layer and the silicon-containing precipitate layer, the lower high-density precipitate is slowly discharged through the bottom slag discharge valve. The upper slurry is then introduced into a secondary settling tank, where residual fine particles are removed by slow cyclone separation, and then fine silicate solids are further removed by a filtration device. Before filtration, adding 0.01-0.05% cationic flocculant can promote particle aggregation and improve the separation rate. The upper liquid after three-stage separation is high-purity recycled lime slurry, which can be dried to obtain recycled lime with a CaO content of more than 90%.

4. The method for separating silicon-containing impurities from recycled lime according to claim 1, characterized in that, The silicon-containing precipitate after the reaction in S4 can be further dried and sieved after solid-liquid separation to prepare silicon-containing by-products and realize resource utilization. Specifically, the obtained sediment is centrifuged to remove water, then dried at 80-120℃ for 3-6 hours to reduce its moisture content to less than 5%, and then sieved to form powder with a particle size of less than 1mm.

5. The method for separating silicon-containing impurities from recycled lime according to claim 1, characterized in that, In step S1, to improve the separation effect of silicon-containing impurities in recycled lime, the recycled lime is pre-classified and its particle size is controlled before the reaction step. The recycled lime is screened by a vibrating screen before entering the reaction device, and the screen aperture is set to 0.2-1.5 mm. After the recycled lime is screened, it enters the reaction tank and the reaction water is added gradually in a pulse water addition method. Each addition of water accounts for 10% to 15% of the total water volume, and the interval is 2 to 5 minutes.

6. The method for separating silicon-containing impurities from recycled lime according to claim 3, characterized in that, In the separation step, S3 uses a dynamic fluidized bed separator instead of a traditional static settling structure to accelerate the relative migration rate of silicon-containing impurities and calcium hydroxide. The device includes a cylindrical reaction vessel, a bottom gas distribution plate and a circulation pump system. By introducing microbubbles or low-speed stirring during the separation stage to form a slightly fluidized state, the calcium hydroxide particles with a smaller specific gravity rise to the liquid surface, while silicon-containing impurities with a specific gravity greater than 2.5 g / cm³ settle to the bottom. During the separation process, the microbubble introduction rate can be maintained at 0.2–0.5 m³ / h to maintain the stability of the stratification interface; Once the stratification is stable, open the bottom slag discharge port to discharge the silica-containing sediment, and the upper liquid enters the storage tank through the overflow pipe. By using dynamic separation instead of static separation, the separation time can be reduced from 2-6 hours to 20-40 minutes while maintaining separation accuracy.

7. The method for separating silicon-containing impurities from recycled lime according to claim 1, characterized in that, The reaction between recycled lime and water in S1 is carried out using a multi-stage hydration control system, which is divided into a primary reaction stage and an enhanced reaction stage. In the initial stage, the reaction temperature is controlled at 40-50℃ to allow calcium oxide to slowly hydrate and generate calcium hydroxide. In the intensification stage, the system temperature is raised to 70-80℃ and stirred continuously for 20-40 minutes to accelerate the hydration reaction and promote density stratification.

8. The method for separating silicon-containing impurities from recycled lime according to claim 1, characterized in that, The S4 layering stage introduces an interface optical detection system to identify the layering state in real time. The detection system includes a laser transmission module, a reflected light receiving module, and an image recognition algorithm. The interface height between the upper calcium hydroxide slurry and the lower silicon-containing deposition layer is determined by monitoring the change in the intensity of scattered light in the slurry. Once the interface stabilizes, the slag discharge valve is automatically triggered.

9. A method for separating silicon-containing impurities from recycled lime according to claim 8, characterized in that, In the layering stage, the interface position between the calcium hydroxide slurry and the silicon-containing deposition layer is calculated using an optical detection module and a computer vision algorithm; The detection module includes a high-resolution camera and a laser illumination device to acquire images of scattered light inside the slurry. The system uses the gray-level distribution function G(x,y) to calculate the light intensity gradient and identifies the interface contour lines using edge detection algorithms (such as the Sobel or Canny operator). The interface position height h is calculated by the following formula: ； Where h is the pixel position corresponding to the point of maximum light intensity change, which is converted into actual height and used to control the opening time of the slag discharge valve; When the interface height changes rate When the flow rate is less than 0.5 mm / min, the system determines that the stratification is stable and automatically enters the slag discharge stage.

10. A method for separating silicon-containing impurities from recycled lime according to claim 9, characterized in that, After separation, the desiliconization effect and the purity of the recycled lime are evaluated in real time using a computational model; The silicon removal efficiency η is calculated using the following formula: ； Where C0 is the mass fraction of silicon in the recycled lime sample before reaction, and C1 is the mass fraction of silicon in the upper product after separation. Purity of calcium oxide in recycled lime The following approximate relationship is satisfied by indirect calculation using the conductivity method: ； in The conductivity of the standard solution To test the conductivity of the sample, k is a constant obtained through calibration; System automatically collects and and outputs the values of η and in real time. When η ≥ 85% and ≥ 90%, it is determined that the separation is qualified; This computational model enables quantitative evaluation and closed-loop quality control of the silicon removal process, providing data support for industrial processes.

Images