A stable electric porcelain blank based on natural material correction and its preparation and application

Abstract

This invention discloses a method for stabilizing the composition of electrical porcelain blanks based on raw material correction, belonging to the field of electrical porcelain manufacturing technology. This method pioneers a "main blank preparation, micro-correction" strategy: through statistical analysis of long-term production data, the components requiring key correction and the correcting raw materials are determined; the core process of "pre-preparing correcting raw material slurry – preparing initial blank blank – accurately calculating correcting components – homogenizing and mixing the corresponding slurry" achieves component control, i.e., the blank is prepared using the raw material ratio determined by the original formula; by analyzing the known initial blank composition, a small amount of precisely known pre-prepared correcting raw material is used to construct and solve a system of linear equations, achieving precise fine-tuning of the main slurry, ultimately achieving dual stability of the blank composition and performance. Through micro-compensation of the correcting raw materials, the blank composition deviation can be controlled within ±0.3%, and the process performance compliance rate is increased to over 99.5%, significantly improving the qualification rate of electrical porcelain products.

Description

Technical Field

[0001] This invention belongs to the field of electrical porcelain blank preparation technology, specifically relating to the preparation and application of a stable electrical porcelain blank composition based on raw material correction. Background Technology

[0002] The quality stability of electrical porcelain depends on the stability of its raw material composition. However, the main raw materials used in manufacturing electrical porcelain (clay, feldspar, calcined bauxite, and quartz) are all natural minerals, and their chemical composition inevitably fluctuates due to factors such as geological conditions, resource distribution, and mining season. For example, the Al2O3 content in clay can fluctuate by ±10%, and the K2O+Na2O content in feldspar can fluctuate by ±8%, sometimes even more significantly. Fluctuations in raw material composition lead to instability in the raw material composition, which in turn causes changes in the phase composition of the electrical porcelain product, thus affecting its performance and reliability in use.

[0003] Existing technologies typically employ a "fixed formula + raw material screening" approach to address fluctuations, selecting raw materials with relatively stable compositions while maintaining the same formula. This method has significant drawbacks: first, there is a shortage of standardized raw materials, and the procurement cost of high-quality, relatively stable raw materials is high (30-50% higher than ordinary raw materials); second, it cannot completely avoid batch-to-batch fluctuations in raw materials, with billet composition deviations still reaching ±5% or more; and third, when raw material composition fluctuations exceed expectations, there is a lack of effective online control methods, leading to product performance fluctuations and affecting the stable operation of power transmission and transformation systems.

[0004] Therefore, there is an urgent need for a method that can stably control the composition of electric porcelain blanks online without relying on expensive and high-quality raw materials. Summary of the Invention

[0005] The purpose of this invention is to provide a method for stabilizing the composition of electrical porcelain blanks based on raw material correction, in order to solve the problem of unstable composition of electrical porcelain blanks caused by fluctuations in the composition of natural raw materials. This process achieves dual stability of blank composition and performance through the core steps of "preparing corrected raw material slurry - preparing initial blank blanks - accurately calculating corrected components - homogenizing and mixing the corresponding slurry".

[0006] This method, through precise control of raw materials, keeps the composition deviation of the blank within ±0.3%, increases the process performance compliance rate to over 99.5%, significantly improves the qualification rate of electrical porcelain products, and is suitable for the large-scale production of various electrical porcelain blanks. It overcomes the shortcomings of existing technologies that rely on stable raw materials and cannot actively correct composition fluctuations.

[0007] The key concept of this invention lies in adopting a collaborative control strategy of "main billet preparation and micro-correction." First, based on statistical analysis of long-term production data, the components in the billet requiring key control are proactively identified, and a correction system is pre-planned. In actual production, the main billet prepared using a familiar "initial stock" serves as the "main framework." Then, depending on the specific circumstances, a small amount of precisely known correction material is used to precisely correct the main component composition through "micro-compensation." This method ensures the stability of the billet's basic properties while providing the production line with the flexibility to cope with raw material fluctuations.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for stabilizing the composition of electrical porcelain blanks based on natural raw materials includes the following steps: S1. Determine the benchmark material volume and prepare the calibration raw material slurry: The billet formula verified by pilot-scale and long-term production practice is defined as the basic formula, and its chemical composition is the benchmark formula, which serves as the basis for billet composition control and correction. Based on long-term statistical analysis of billet composition data in electrical porcelain production, the target components that need to be controlled in the billet are determined by comparing with the benchmark formula, and corresponding raw materials are selected as correction raw materials. The selected calibration raw materials are ground with water to a predetermined fineness and then stored in a mud tank equipped with a stirring device for continuous stirring and homogenization. The chemical composition of the calibration raw materials is accurately determined and a calibration raw material composition file is established for future use. S2. Preparation of the main material billet: Test the main chemical components and processing properties of each batch of raw materials entering the factory, and establish a raw material database; Based on the basic formula, the composition and properties of the raw materials entering the factory, the ratio of billet and raw materials is determined, thus obtaining the production material formula; the raw materials are prepared and ground according to the production material formula to obtain an initial slurry with qualified particle size and gradation; the composition of the initial slurry is quickly tested and analyzed; S3. Micro-correction and homogenization of billet composition: By comparing the differences between the initial slurry composition and the baseline slurry composition, the required correction material is determined, and the amount of the required correction material is calculated. Based on the calculation results, each calibration raw material slurry is added to the initial slurry slurry tank through a high-precision metering pump. Then, dispersant and binder are added, and the mixture is stirred and homogenized to obtain a homogenized slurry with stable composition. This slurry is called new slurry. The leftover material from the same material block recovered during the molding process, or the unqualified clay blanks from the same material block that have not been fired, are crushed, dispersed, and slurried. The slurry is then passed through a 240-mesh sieve, with a residue of ≤0.4%, to obtain recycled clay slurry, also known as old slurry. Based on the dry basis of the mud, the new mud and the old mud are pumped into the mixing tank in a 1:3 ratio using a flow pump and continuously stirred to form a uniform working mud. S4. Subsequent processing and molding: The working slurry is sieved, iron removed, pressure filtered and dehydrated, aged, and vacuum-kneaded. Then it is shaped, dried, glazed, fired, inspected, assembled, and inspected before leaving the factory to obtain qualified electrical porcelain products.

[0009] Preferably, in step S1, the screening criteria for the calibration raw materials are: Based on the incoming inspection data of raw materials purchased in the past two years and the company's database of electric porcelain blank composition in the past two years, raw materials with a composition fluctuation rate of no more than ±5% and stable supply are selected. The corrective materials include feldspar, clay, quartz, and aluminous materials; The feldspar correction material is high-purity potassium feldspar with a K2O content of 10-15% and low Fe2O3 and TiO2 impurity content. The clay-based corrective material is a kaolinite-based material with an Al2O3 content of 25-35%, a plasticity index of 15-25, and low Fe2O3 and TiO2 impurity content. The quartz-based correction material is quartz ore with a SiO2 content ≥98% and low Fe2O3 and TiO2 impurity content; The aluminum-based corrective raw materials include bauxite and / or industrial alumina, wherein the bauxite is calcined bauxite with an Al2O3 content of 80-90% and low Fe2O3 and TiO2 impurity content; and the industrial alumina has an Al2O3 content of ≥99%.

[0010] Preferably, the grinding and testing requirements for the calibration raw materials in S1 are as follows: Pretreatment: If the raw material is in large pieces, crush it to a particle size ≤ 5mm before grinding it in a ball mill; if it is not in large pieces, grind it directly. Grinding process: Feldspar: Use high-alumina ceramic balls as the grinding medium, with a ball-to-material ratio of 2:1, and a grinding time of 4-5 hours; Clay: Use high-alumina ceramic balls as the grinding medium, with a ball-to-material ratio of 1.8:1, and a grinding time of 2-4 hours; Quartz: High-alumina ceramic balls are used as the grinding medium, with a ball-to-material ratio of 2:1 and a grinding time of 3-5 hours; Bauxite: Use high-alumina ceramic balls or corundum balls as the grinding medium, with a ball-to-material ratio of 3:1 and a grinding time of 5-6 hours; The grinding fineness is ≤0.4% residue on a 240-mesh sieve; Homogenization: The ground and corrected raw material slurry is placed in a slurry tank equipped with a stirring device and continuously stirred for no less than 24 hours; Composition analysis: The components of SiO2, Al2O3, Fe2O3, TiO2, CaO, MgO, K2O and Na2O in the calibration raw material are determined, and the detection error is controlled within ±0.1%.

[0011] Preferably, the preparation parameters of the initial slurry in S2 are as follows: with a ball-to-material ratio of 2:1 and a grinding time of 3-5 hours, the slurry is ground until the residue on a 240-mesh sieve is ≤0.4% to obtain the initial slurry; after the slurry is put into the mud tank, it is stirred at a speed of 50-80 r / min for no less than 25-30 minutes, and after uniformity, a sample is taken to test its chemical composition.

[0012] Preferably, the amount of corrective raw material added in S3 is calculated according to the following formula: Correction material addition amount = (target component value - initial slurry component value) × initial slurry total amount / (correction material component value - target component value).

[0013] Preferably, in S3, The dispersant is an inorganic phosphate, and the addition amount is 0.1% to 0.3% of the total amount of mud (on a dry basis). The binder is a water-soluble polymer, and its addition amount is 0.2% to 0.5% of the total amount of mud (on a dry basis). The stirring time after adding the dispersant and binder is 30-45 minutes.

[0014] Preferably, the pretreatment process parameters in S4 are: The sieving process uses a 240-mesh sieve. Iron removal uses a strong magnetic iron removal device with a magnetic field strength of not less than 12,000 Gauss; The moisture content of the dehydrated mud cake is 20%~22%; The aging process is carried out in a constant temperature and humidity environment, with a temperature of 20~25℃, a relative humidity of ≥95%, and an aging time of 24~72 hours. The vacuum degree of vacuum plowing is ≤-0.095MPa.

[0015] Preferably, the post-processing parameters in S4 are: Drying: Follow the company's drying curve, with a maximum drying temperature of 80~120℃, and a moisture content of ≤1% after drying; Firing: Follow the company's firing curve, with a maximum firing temperature of 1250~1320℃ and a high-temperature holding time of 2~4 hours.

[0016] A method for stabilizing the composition of electrical porcelain blanks based on natural raw material correction is applied in the preparation of blanks for high and low voltage porcelain insulators, surge arrester porcelain parts, or rod-shaped porcelain insulators for electrified railway lines. By adding corrective raw materials, the composition of the blanks is stabilized, and the uniformity of moisture content and the stability of the processing performance of the blanks are ensured by controlling the aging time.

[0017] Beneficial effects: The method provided by this invention effectively solves the problem of instability in electrical porcelain blanks caused by fluctuations in the composition of natural raw materials. Through the core process of "pre-preparing corrective raw material slurry - preparing initial raw material blanks - accurately calculating corrective components - homogenizing and mixing the corresponding slurry," dual stability of composition and performance is achieved. Specific effective effects include: The specific steps of this method include: determining four categories of calibration raw materials based on historical data and pre-preparing and storing them; calculating the initial formula and preparing the initial slurry based on the composition of the incoming raw materials; using the calibration raw materials to correct the composition of the initial slurry; mixing and adding additives and recycled mud slurry; and then further processing to obtain qualified blanks. This invention, through precise control of the calibration raw materials, manages the blank composition deviation within ±0.3%, increasing the process performance compliance rate to over 99.5%, significantly improving the qualification rate of electrical porcelain products, and is suitable for the large-scale production of various electrical porcelain blanks. It overcomes the shortcomings of existing technologies that rely on stable raw materials and cannot actively correct composition fluctuations.

[0018] This method for stabilizing the composition of electrical porcelain blanks based on natural raw material correction has the following advantages: 1) Significantly improved composition stability: By correcting the precise control of raw materials, the deviation of billet composition has been reduced from ±5% or more in traditional processes to within ±0.3%, and harmful impurities such as Fe2O3 are more precisely controlled.

[0019] 2) Enhanced raw material adaptability: Common raw materials with large fluctuations in composition (fluctuation within ±5%) can be used, reducing procurement costs by 30-50%.

[0020] 3) Improved process flexibility: By adjusting the amount of raw materials added, fluctuations in raw material composition can be addressed in real time, avoiding the scrapping of the entire batch and increasing the raw material utilization rate to over 95%.

[0021] 4) Stable product quality: The compliance rate of raw material processing performance (plasticity index 15~20, drying strength ≥3MPa) has been increased to over 99.5%, and the firing qualification rate of electric porcelain products has been increased from 85~90% to over 98%.

[0022] 5) Achieving a highly efficient balance between "stable framework and micro-adjustment": using the main raw material to ensure the performance baseline, and using micro-adjustment raw materials to accurately compensate for deviations, optimizing resource allocation, resulting in low cost and high efficiency. Achieving a balance between stability and cost. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the framework of the method of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to implementation examples and accompanying drawings. The following embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection.

[0025] The basic process of the method of this invention is as follows: Figure 1 As shown, it includes four main stages: selection and pre-processing of raw materials, preparation of initial formula, component correction and mixing, and subsequent processing and molding.

[0026] A method for stabilizing the composition of electrical porcelain blanks based on natural raw material correction, the framework process is as follows: Figure 1 As shown, Includes the following steps: (1) Selection of calibration raw materials and pre-preparation of calibration raw material slurry Calibration Raw Material Screening: Based on the company's raw material procurement and inspection database for the past two years, raw materials with small compositional fluctuations (≤±5%) and stable supply were selected as calibration raw materials, and divided into four categories: Feldspar correction raw materials: Select high-purity potassium feldspar with a K2O+Na2O content of 10~15% and low Fe2O3 and TiO2 impurity content; Clay-based corrective raw materials: Select kaolin with an Al2O3 content of 25-35%, a plasticity index of 15-25, and low Fe2O3 and TiO2 impurity content; Quartz-based correction raw materials: Select quartz sand with SiO2 content ≥98% and low Fe2O3 and TiO2 impurity content; The corrective raw materials for aluminum materials include bauxite and / or industrial alumina. Among them, bauxite is calcined bauxite with an Al2O3 content of 80-90% and low Fe2O3 and TiO2 impurity content; industrial alumina has an Al2O3 content of ≥99%.

[0027] Correction material processing: Various correction materials are crushed (particle size ≤ 5mm) separately and then fed into a dedicated ball mill for grinding. Feldspar and quartz: Use high-alumina ceramic balls as the grinding medium, with a ball-to-material ratio of 2:1, and a grinding time of 4-5 hours; Clay: Use high-alumina ceramic balls as the grinding medium, with a ball-to-material ratio of 1.8:1, and a grinding time of 4-5 hours; Bauxite: Use high-alumina ceramic balls or corundum ceramic balls as the grinding medium, with a ball-to-material ratio of 3:1 and a grinding time of 5-6 hours; Ensure that all calibration raw materials have a fineness of ≤0.4% residue on a 240-mesh sieve.

[0028] Homogenization and composition analysis: The ground calibration raw material slurry is stored in a special mud tank equipped with a stirring device (stirring speed 60~100r / min) and continuously stirred for more than 24 hours to homogenize; The components (SiO2, Al2O3, Fe2O3, K2O+Na2O, TiO2, CaO, MgO) are accurately determined using multi-element rapid analysis or X-ray fluorescence analysis. The analytical error is controlled within ±0.1%. A calibration raw material composition file is established and sealed for later use (storage time ≤7 days; if the storage time exceeds this period, the composition must be re-analyzed).

[0029] (2) Preparation of initial material formula Incoming raw material inspection: For each batch of raw materials (non-calibration raw materials) entering the factory, the main components are detected using a multi-element rapid analyzer (detection error ≤ ±0.3%), and the component data are recorded.

[0030] Initial formula calculation: Based on the target composition of the billet (such as typical targets for high voltage electrical porcelain: SiO2 62%-65%, Al2O3 24%-27%, Fe2O3≤0.5%, K2O+Na2O 3%-5%), combined with the raw material composition data, the initial addition ratio of various raw materials is calculated using linear programming method.

[0031] Initial slurry preparation: Weigh the raw materials for production according to the calculation results, mix them, and add them to a ball mill (ball-to-material ratio 3:1, grinding time 3-4 hours), grinding until the residue on a 240-mesh sieve is ≤0.4%; The slurry is placed in the initial mud tank and stirred at 50-80 r / min for 30 minutes. Samples are taken and the actual components are detected using a rapid analysis method (with a focus on components that may deviate significantly from the target value).

[0032] (3) Component correction and mixing Correction Calculation: Based on the difference between the actual composition of the initial slurry and the target composition, calculate the required amount of various correction materials to be added. The calculation formula is as follows: Corrected raw material addition amount (kg) = (Target component value - Initial component value) * Initial slurry total amount (kg) / (Corrected raw material component value - Target component value) For example: the initial slurry has an Al2O3 content of 23% (target 25%), the total initial slurry volume is 1000kg, and the bauxite correcting material has an Al2O3 content of 85%. Then the amount of bauxite correcting material to be added is approximately 33.3kg (25-23) * 1000 / (85-25).

[0033] It is also stipulated that the amount of a single corrective material added shall not exceed 10% of the total slurry volume, so as to avoid excessive correction affecting the performance of the billet.

[0034] Adding calibration raw materials: According to the calculation results, various calibration raw material slurries are sent from the dedicated slurry tank to the working slurry tank through a high-precision metering pump (accuracy ±0.2%), and the stirring is turned on (speed 100~150r / min).

[0035] Additives and recycled sludge: Add 0.1~0.3% sodium hexametaphosphate (dispersant) and 0.2~0.5% sodium carboxymethyl cellulose (binder), and stir for 30-45 minutes; Add 70% of the total mud volume of recycled mud (which needs to be pre-ground to ≤0.4% residue on a 240-mesh sieve and its composition tested), and continue stirring for 20-30 minutes to make the mud composition and performance uniform and stable.

[0036] (4) Post-processing and molding Mud purification: The mixed mud is passed through a 240-mesh sieve, with a residue of ≤0.4%, and then magnetic iron impurities are removed by a strong magnetic separator (magnetic field strength ≥12000 Gauss).

[0037] Raw material preparation: The purified mud slurry is dewatered to a moisture content of 21-22% by a plate and frame filter press to form mud cakes; after coarse kneading, the mud cakes are sent to an aging chamber and aged for 24-72 hours in a constant temperature and humidity environment (20-25℃, relative humidity ≥95%) to balance the moisture distribution; the aged mud is treated by a vacuum plow (vacuum degree ≤0.095MPa) to remove internal air bubbles and form dense and uniform raw materials.

[0038] Forming and firing: The blanks are formed using the plastic method according to product requirements, dried (temperature 80~120℃, final moisture content ≤1%), glazed, and then fired in a tunnel kiln (maximum temperature 1250~1350℃, holding for 2~4 hours). Finally, qualified electrical porcelain products are obtained through porcelain inspection.

[0039] Example 1: Preparation of 220kV High Voltage Insulator Blanks Target billet composition: SiO2 68.28%, Al2O3 27.42%, Fe2O3 0.54%, K2O+Na2O 3.76%.

[0040] Correcting raw material composition: Feldspar corrective material: SiO2 67.30%, Al2O3 18.93%, K2O+Na2O 13.67%, Fe2O3 0.11%; Clay-based corrective material: SiO2 63.07%, Al2O3 36.69%, Fe2O3 0.23%; Quartz-based corrective material: SiO2 99.95%, Fe2O3 0.05%; Bauxite calibration materials: Al2O389.19%, SiO210.49%, Fe2O30.32%.

[0041] A method for stabilizing the composition of electrical porcelain blanks based on natural raw materials includes the following steps: Initial formulation preparation: Raw material composition: ordinary clay (SiO2 68.18%, Al2O3 31.82%), ordinary feldspar (SiO2 86.84%, K2O+Na2O 13.16%), quartz sand (SiO2 100%), calcined bauxite (Al2O3 100%). Initial formula calculation: ordinary clay 35%, ordinary feldspar 20%, quartz sand 30%, calcined bauxite 15%; Initial slurry test results: SiO2 70.35% (1.5% higher), Al2O3 25.97% (1.5% lower), K2O+Na2O 3.25% (0.5% lower), Fe2O3 0.43% (qualified).

[0042] Ingredient correction: The calculation of the correction amount is as follows: 30 kg of bauxite correction material (to compensate for Al2O3), 17 kg of feldspar correction material (to compensate for K2O+Na2O), and a reduction in quartz content (by adding other correction materials for dilution). The total amount of this addition is less than 5% of the total initial slurry (1000 kg), which fully reflects the feature of this invention to achieve precise control with micro-compensation. The main properties and structure of the billet are still determined by the initial material.

[0043] The corrected slurry composition is: SiO2 66.56%, Al2O3 26.60%, K2O+Na2O 3.54%, Fe2O3 0.44%, all of which meet the target requirements.

[0044] Follow-up processing: Add 0.2% sodium hexametaphosphate and 0.3% sodium carboxymethyl cellulose, and stir for 40 minutes; add 15% recycled mud slurry, and stir for 25 minutes; after sieving and removing iron, filter (moisture content 22%), age at 23℃ and 95% humidity for 48 hours, vacuum knead the mud (≤-0.095MPa), shape it into an insulator blank, dry it, glaze it, and fire it at 1280℃ for 3 hours.

[0045] Effect verification: The insulator products have a bending strength of 88MPa, a breakdown voltage of 48kV, and a pass rate of 98.5%, which is 8.5 percentage points higher than that of traditional processes.

[0046] Example 2: Preparation of 110kV medium-voltage insulator blanks (medium voltage level, balancing performance and cost) Target billet composition: SiO2 68.85%, Al2O3 26.36%, Fe2O3 0.48%, K2O + Na2O 4.30% Correcting raw material composition: Feldspar corrective material: SiO2 67.00%, Al2O3 19.43%, K2O + Na2O 13.44%, Fe2O3 0.13% Clay-based corrective material: SiO2 63.21%, Al2O3 36.53%, Fe2O3 0.25% Quartz-based corrective material: SiO2 99.94%, Fe2O3 0.06% Bauxite calibration material: Al2O388.59%, SiO211.07%, Fe2O30.34% Initial formulation preparation: Raw material composition upon arrival at the plant: ordinary clay (SiO2 69.32%, Al2O3 30.68%), ordinary feldspar (SiO2 87.58%, K2O+Na2O 12.42%), quartz sand (SiO2 100.00%), calcined bauxite (Al2O3 100.00%). Initial formula calculation: Ordinary clay 38%, ordinary feldspar 18%, quartz sand 28%, calcined bauxite 16% Initial slurry test results: SiO2 69.76% (1.2% low), Al2O3 25.77% (1.3% low), K2O + Na2O 4.00% (0.4% low), Fe2O3 0.46% (qualified). Ingredient correction: Correction amount calculation (initial slurry total volume 1000kg): Clay-based corrective material: (24.5-23.2)×1000 / (31.5-24.5)≈18.6kg (Al2O3 supplement) Feldspar corrective material: (4.0-3.6)×1000 / (12.8-4.0)≈45.5kg (K2O+Na2O supplement) Quartz-based correction material: (64.0-62.8)×1000 / (98.3-64.0)≈35.0kg (replenishing SiO2) Total amount added: 18.6 + 45.5 + 35.0 = 99.1 kg (9.9% of total weight, ≤10%) Corrected slurry composition: SiO2 67.23%, Al2O3 25.70%, K2O + Na2O 4.20%, Fe2O3 0.44% (meets target) Additives: 0.25% sodium hexametaphosphate + 0.35% sodium carboxymethyl cellulose, stir for 45 min. Add recycled mud: 18% of total mud volume (component testing qualified), stir for 28 minutes. Purification: 240-mesh sieve + 12000 Gauss iron separator Raw material preparation: filter press to a moisture content of 21.5%, age at 22℃ and 96% humidity for 36 hours, and then vacuum knead (≤-0.095MPa). Molding and firing: Plastic molding - drying at 100℃ (final moisture content ≤1%) - glazing - firing at 1270℃ for 3.5 hours Effect verification: The product has a bending strength of 82MPa and a breakdown voltage of 42kV, both of which meet the national standard requirements for 110kV insulators. The pass rate was 98.3%, an improvement of 7.8 percentage points compared to traditional processes. The raw material cost is 15% lower than that of the 220kV product (due to reduced use of high-purity bauxite). Example 3: Preparation of 500kV UHV Insulator Blanks (High Reliability Requirements) Target billet composition: SiO2 68.11%, Al2O3 28.11%, Fe2O3 0.32%, K2O + Na2O 3.46% Correction of raw material composition (high purity grade): Feldspar corrective material: SiO2 67.38%, Al2O3 18.68%, K2O + Na2O 13.85%, Fe2O3 0.08% Clay-based corrective material: SiO2 62.81%, Al2O3 36.98%, Fe2O3 0.20% Quartz-based corrective material: SiO2 99.96%, Fe2O3 0.04% Bauxite calibration material: Al2O390.22%, SiO29.74%, Fe2O30.04% Initial formulation preparation: Raw material composition upon arrival: high-purity clay (SiO2 67.05%, Al2O3 32.95%), high-purity feldspar (SiO2 85.53%, K2O+Na2O 14.47%), high-purity quartz sand (SiO2 100.00%), calcined bauxite (Al2O3 100.00%). Initial formula calculation: High-purity clay 32%, high-purity feldspar 22%, high-purity quartz sand 29%, calcined bauxite 17%. Initial slurry test results: SiO2 69.73% (0.5% higher), Al2O3 25.72% (1.2% lower), K2O + Na2O 4.00% (0.2% lower), Fe2O3 0.45% (qualified). Ingredient correction: Correction amount calculation (initial slurry total volume 1000kg): Bauxite correcting material: (26.0-24.8)×1000 / (88-26.0)≈19.4kg (Al2O3 supplement) Feldspar corrective material: (3.2-3.0)×1000 / (13.2-3.2)≈20.0kg (K2O+Na2O supplement) No quartz-based corrective material (SiO2 is too high, so it is diluted with other corrective materials). Total amount added: 19.4 + 20.0 = 39.4 kg (3.9%, ≤10%) Corrected slurry composition: SiO2 66.42%, Al2O3 27.57%, K2O + Na2O 3.39%, Fe2O3 0.29% (meets target) Additives: 0.3% sodium hexametaphosphate + 0.4% sodium carboxymethyl cellulose, stir for 45 min. Add recycled mud: 12% of total mud volume (high-purity recycled mud, Fe2O3≤0.2%), stir for 30 min. Purification: 240-mesh sieve + 15000 Gauss iron separator (enhanced iron removal) Raw material preparation: filter press to a moisture content of 21.0%, age at 23℃ and 97% humidity for 72 hours (maximum aging time), and then vacuum knead (≤-0.098MPa, higher vacuum). Molding and firing: Plastic molding - drying at 110℃ (final moisture content ≤0.8%) - glazing - firing at 1300℃ for 4 hours (maximum firing temperature) Effect verification: The product has a bending strength of 95MPa and a breakdown voltage of 55kV, far exceeding the national standard requirements for ultra-high voltage insulators. The pass rate was 99.1%, an improvement of 9.2 percentage points compared to traditional processes. The Fe2O3 content is stably controlled below 0.3%, effectively avoiding the potential risk of partial discharge in ceramic parts. Example 4: Preparation of low-voltage porcelain insulator blanks for rural power distribution (low cost, high adaptability) Target billet composition: SiO2 73.25%, Al2O3 20.17%, Fe2O3 0.74%, K2O + Na2O 5.84% Correcting raw material composition (standard purity, cost control): Feldspar corrective material: SiO2 68.31%, Al2O3 18.39%, K2O + Na2O 13.14%, Fe2O3 0.16% Clay-based corrective material: SiO2 64.93%, Al2O3 34.78%, Fe2O3 0.29% Quartz-based corrective material: SiO2 99.93%, Fe2O3 0.07% Initial formulation preparation: Raw material composition upon arrival at the plant: ordinary clay (SiO2 71.26%, Al2O3 28.74%), ordinary feldspar (SiO2 88.31%, K2O+Na2O 11.69%), quartz sand (SiO2 100.00%). Initial formula calculation: 30% ordinary clay, 20% ordinary feldspar, 50% quartz sand (no calcined bauxite, to reduce costs). Initial slurry test results: SiO2 75.06% (1.5% too high), Al2O3 19.16% (1.0% too low), K2O + Na2O 5.11% (0.7% too low), Fe2O3 0.66% (qualified). Ingredient correction: Correction amount calculation (initial slurry total volume 1000kg): Clay-based corrective material: (19.0-18.0)×1000 / (30.0-19.0)≈9.1kg (Al2O3 supplement) Feldspar corrective material: (5.5-4.8)×1000 / (12.5-5.5)≈100.0kg Adjustment: Due to the single addition exceeding 10%, it was diluted with feldspar and a small amount of clay, resulting in a final mixture of 80kg feldspar and 10kg clay. Total added amount after correction: 91 kg (9.1%, ≤10%), SiO2 was reduced to 69.1% through dilution. Corrected slurry composition: SiO2 72.20%, Al2O3 19.48%, K2O + Na2O 5.52%, Fe2O3 0.65% (meets target) Additives: 0.15% sodium hexametaphosphate + 0.2% sodium carboxymethyl cellulose (reduce the amount of additives), stir for 30 minutes. Add recycled mud: 25% of total mud volume (to maximize recycling and reduce raw material consumption), stir for 25 minutes. Purification: 240 mesh sieve + 10000 Gauss iron separator (simplified iron removal) Raw material preparation: filter press to a moisture content of 22.0%, age at 24℃ and 95% humidity for 24 hours (minimum aging time), and then vacuum knead (≤-0.092MPa). Molding and firing: Plastic molding - drying at 90℃ (final moisture content ≤1.2%) - glazing - firing at 1250℃ for 2.5 hours (minimum firing temperature) Effect verification: The product has a drying strength of 3.0 MPa and a breakdown voltage of 15 kV, meeting the national standard requirements for low-pressure porcelain insulators. The pass rate was 98.0%, an improvement of 6.5 percentage points compared to traditional processes. Raw material costs are reduced by 42% (no high-cost bauxite + high amount of recycled mud), which meets the low-cost demand for rural power distribution.

[0047] Example 5: Composition control of 70kN anti-pollution suspension porcelain insulator. Through pilot testing and production practice, the raw materials and their proportions (mass percentage) of 70kN anti-pollution suspension porcelain insulator were determined as follows: Banshan clay (15), Jiangchong clay (11), Changfeng clay (18), Guangdong white clay (18), Fujian black clay (10), calcined bauxite (10), Zuoyun clay (12), and Hubei clay (6). This is the basic formula.

[0048] The corresponding billet chemical composition (mass percentage) is: SiO2 (55.39%), Al2O3 (30.76%), MgO (0.43%), CaO (0.23%), TiO2 (1.06%), K2O (3.10%), Na2O (0.28%), Fe2O3 (1.63%), and loss on ignition (7.12%). This is the reference material formula.

[0049] 1) Left-hand mud, bauxite powder, and feldspar powder were selected as calibration raw materials, and their chemical composition data are listed in Table 1. They were ground to the specified particle size distribution range, stored in a mud pit or mud bucket, stirred evenly, and then samples were taken to test their composition for later use. The oxide components in the test results were converted into K2O, Al2O3, and SiO2 components using the Richter's method. In the Richter's method, TiO2 and Fe2O3 were multiplied by coefficients of 1.7 and 0.9, respectively, to convert to Al2O3; while Na2O, CaO, and MgO were multiplied by coefficients of 1.5, 1.68, and 2.35, respectively, to convert to K2O. The conversion results are listed in Table 1.

[0050] Table 1 Chemical composition and three-component values ​​of the corrected raw materials

[0051] Note 1: The above data is calculated using the component data with "no ignition loss".

[0052] Note 2: Al2O3* and K2O* are values ​​calculated using the Richter's method.

[0053] 2) Weigh all raw materials according to the basic formula requirements, add them to the ball mill, grind them to the specified particle size distribution range, put them into the mud tank, stir evenly, and test their composition. Compare the tested composition with the composition of the reference material. In this example, the deviation between the two is less than 3%, so no correction is needed, and proceed directly to the next process (Table 2). The specific process of preparing the electric porcelain is omitted.

[0054] Table 2 shows that if the deviation from the reference volume is less than 3%, no correction is needed.

[0055] 3) If the composition of the newly prepared billet deviates from that of the reference billet by more than 3%, correction is required. For example, if the deviation between the newly prepared billet and the reference billet in Table 3 is greater than 3%, correction using correction material slurry is necessary.

[0056] The detected component data is converted into three components, K2O, Al2O3 and SiO2, using the Richter method. Then, the components are compared with those of the reference material, and the two oxides with lower contents are selected. Then, two correction materials with higher contents of the corresponding oxides are selected from the correction materials. A system of three linear equations is formed, and by solving it, the amount of correction material to be added can be calculated.

[0057] Table 3 shows that deviations from the reference volume exceeding 3% require correction.

[0058] Compared with the reference material, the composition of the billets listed in Table 3 (in the ternary data row) shows a slightly higher SiO2 content and a slightly lower Al2O3 content, with deviations exceeding 3%, while the K2O content is relatively close. Therefore, bauxite powder and feldspar were selected as correction materials. Let the newly prepared billet be x (without loss on ignition, the same below), bauxite powder be y, and feldspar be z, then the following relationships hold: 61.93x + 7.53y + 65.72z = 59.63 (Meaning: The sum of SiO2 in the newly prepared billet and the correcting raw material is equal to the SiO2 in the reference material.) 33.55x + 92.35y + 19.23z = 35.84 (Meaning: The sum of Al2O3 in the newly prepared billet and the correcting raw material is equal to the Al2O3 in the reference material.) 5.32x + 0y + 16.57z = 5.30 (Meaning: The K2O of the newly prepared billet and the correcting raw material is equal to the K2O of the reference material.) Solving for x, we get: x = 0.94 y = 0.04 z = 0.02 To prepare 100 kg of billet (without loss on ignition), simply add 4 kg of bauxite powder and 2 kg of feldspar powder (correction material) to maintain a billet composition essentially consistent with the reference material. The materials with loss on ignition can be converted to materials with loss on ignition using the following table (Table 4).

[0059] Table 4 Billet Correction and Batching Calculation Table

[0060] To prepare 100 kg of billet containing loss on ignition, only 3.73 kg of bauxite powder containing loss on ignition and 1.87 kg of feldspar powder containing loss on ignition (correction material) need to be added to obtain billet with the same composition as the reference material.

[0061] Since both the newly prepared billet and the calibration raw material have been ground into slurry, once the density of the above materials in their oven-dry state and the density of the corresponding slurry are determined, the following formula can be used:

[0062] Where: Wd — mass of dry material per unit volume of mud ρ v —Density of mud, [g / cm³] 3 ]ρ t —True density of dry material, [g / cm³] 3 ] Convert the dry material mass into slurry volume, and use a flow meter or other slurry volume measuring tool to easily adjust and correct the formula.

[0063] In October 2024, the company began using a raw material correction method to control the composition of billets. Before this method, prior to October 2024, although all raw materials were weighed strictly according to the basic formula, the chemical composition of the prepared billets varied significantly compared to the baseline formula. For example, the SiO2 content ranged from 48.74% to 63.38%, a range of 14.64%. Using the ratio of range to average as the volatility, the volatility was as high as 25.88%, while the volatility of Al2O3 was even higher at 50.87%, and K2O at 14.36%. Other impurity elements also exhibited high volatility (Table 5). After October 2024, the raw material correction method was adopted to control the billet composition, and the main chemical composition of the resulting billets stabilized, with a deviation of less than 3% from the baseline formula (Table 6). With the billet composition stabilized, product quality improved significantly, resulting in substantial increases in the company's economic benefits.

[0064] Table 5 Chemical Composition of Raw Materials Produced by Enterprises in 2024

[0065] Table 6 Chemical Composition of Raw Materials Produced by the Enterprise from January to October 2025

[0066] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for stabilizing the composition of electrical porcelain blanks based on raw material correction, characterized in that, Includes the following steps: S1. Determine the benchmark material volume and prepare the calibration raw material slurry: The billet formula verified through pilot-scale testing and long-term production practice is defined as the basic formula, and its chemical composition is the benchmark formula, which serves as the basis for billet composition control and correction. Based on long-term statistical analysis of raw material composition data in electrical porcelain production, the target components that need to be controlled in the raw material are determined by comparing with the benchmark raw material, and the corresponding raw materials are selected as correction raw materials. After the selected calibration raw materials are ground to the predetermined fineness with water, they are stored in a special mud tank equipped with a stirring device for stirring and homogenization; their chemical composition is accurately determined, and a calibration raw material composition file is established for future use. S2. Preparation of the main material billet: Test the main chemical components and processing properties of each batch of raw materials entering the factory, and establish a raw material database; Based on the basic formula, the composition and properties of the raw materials entering the factory, the raw material ratio of the billet is determined, thus obtaining the production material formula; the raw materials are prepared and ground according to the production material formula to obtain an initial slurry with qualified particle size and gradation; the composition of the initial slurry is quickly tested and analyzed. S3. Micro-correction and homogenization of billet composition: By comparing the differences between the initial slurry composition and the baseline slurry composition, the required correction material is determined, and the amount of the required correction material is calculated. Based on the calculation results, each calibration raw material slurry is added to the initial slurry slurry tank through a high-precision metering pump. Then, dispersant and binder are added, and the mixture is stirred and homogenized to obtain a homogenized slurry with stable composition. This slurry is called new slurry. The leftover material from the same material block recovered during the molding process, or the unqualified clay blanks from the same material block that have not been fired, are crushed, dispersed, and slurried. The slurry is then passed through a 240-mesh sieve, with a residue of ≤0.4%, to obtain recycled clay slurry, also known as old slurry. Based on the dry basis of the mud, the new mud and the old mud are pumped into the mixing tank in a 1:3 ratio using a flow pump and continuously stirred to form a uniform working mud. S4. Subsequent processing and molding: The working slurry is sieved, iron removed, pressure filtered and dehydrated, aged, and vacuum-kneaded. Then it is shaped, dried, glazed, fired, inspected, assembled, and inspected before leaving the factory to obtain qualified electrical porcelain products.

2. The method according to claim 1, characterized in that, In S1, the screening criteria for the calibration raw materials are: Based on the incoming inspection data of raw materials purchased in the past two years and the company's database of electric porcelain blank composition in the past two years, raw materials with a composition fluctuation rate of no more than ±5% and stable supply are selected. The corrective materials include feldspar, clay, quartz, and aluminous materials; The feldspar correction material is high-purity potassium feldspar with a K2O content of 10-15% and low Fe2O3 and TiO2 impurity content. The clay-based corrective material is a kaolinite-based material with an Al2O3 content of 25-35%, a plasticity index of 15-25, and low Fe2O3 and TiO2 impurity content. The quartz-based correction material is quartz ore with a SiO2 content ≥98% and low Fe2O3 and TiO2 impurity content; The aluminum-based corrective raw materials include bauxite and / or industrial alumina, wherein the bauxite is calcined bauxite with an Al2O3 content of 80-90% and low Fe2O3 and TiO2 impurity content; and the industrial alumina has an Al2O3 content of ≥99%.

3. The method according to claim 1, characterized in that, The grinding and testing requirements for the calibration raw materials in S1 are as follows: Pretreatment: If the raw material is in large pieces, crush it to a particle size ≤ 5mm before grinding it in a ball mill; if it is not in large pieces, grind it directly. Grinding process: Feldspar: Use high-alumina ceramic balls as the grinding medium, with a ball-to-material ratio of 2:1, and a grinding time of 4-5 hours; Clay: Use high-alumina ceramic balls as the grinding medium, with a ball-to-material ratio of 1.8:1, and a grinding time of 2-4 hours; Quartz: High-alumina ceramic balls are used as the grinding medium, with a ball-to-material ratio of 2:1 and a grinding time of 3-5 hours; Bauxite: Use high-alumina ceramic balls or corundum balls as the grinding medium, with a ball-to-material ratio of 3:1 and a grinding time of 5-6 hours; The grinding fineness is ≤0.4% residue on a 240-mesh sieve; Homogenization: The ground and corrected raw material slurry is placed in a slurry tank equipped with a stirring device and continuously stirred for no less than 24 hours; Composition analysis: The components of SiO2, Al2O3, Fe2O3, TiO2, CaO, MgO, K2O and Na2O in the calibration raw material are determined, and the detection error is controlled within ±0.1%.

4. The method according to claim 1, characterized in that, The initial slurry preparation parameters in S2 are as follows: with a ball-to-material ratio of 2:1 and a grinding time of 3-5 hours, the slurry is ground until the residue on a 240-mesh sieve is ≤0.4% to obtain the initial slurry; after the slurry is placed in the mud tank, it is stirred at a speed of 50-80 r / min for no less than 25-30 minutes, and after uniformity, a sample is taken to test its chemical composition.

5. The method according to claim 1, characterized in that, The amount of corrective raw material added in S3 is calculated according to the following formula: Correction material addition amount = (target component value - initial slurry component value) × initial slurry total amount / (correction material component value - target component value).

6. The method according to claim 1, characterized in that, In S3, The dispersant is an inorganic phosphate, and the addition amount is 0.1% to 0.3% of the total amount of mud (on a dry basis). The binder is a water-soluble polymer, and its addition amount is 0.2% to 0.5% of the total amount of mud (on a dry basis). The stirring time after adding the dispersant and binder is 30-45 minutes.

7. The method according to claim 1, characterized in that, The pretreatment process parameters in S4 are as follows: The sieving process uses a 240-mesh sieve. Iron removal uses a strong magnetic iron removal device with a magnetic field strength of not less than 12,000 Gauss; The moisture content of the dehydrated mud cake is 20%~22%; The aging process is carried out in a constant temperature and humidity environment, with a temperature of 20~25℃, a relative humidity of ≥95%, and an aging time of 24~72 hours. The vacuum degree of vacuum plowing is ≤-0.095MPa.

8. The method according to claim 1, characterized in that, The post-processing parameters in S4 are as follows: Drying: Follow the company's drying curve, with a maximum drying temperature of 80~120℃, and a moisture content of ≤1% after drying; Firing: Follow the company's firing curve, with a maximum firing temperature of 1250~1320℃ and a high-temperature holding time of 2~4 hours.

9. A method for stabilizing the composition of electrical porcelain blanks based on natural raw materials, as described in any one of claims 1 to 8, is applied in the preparation of blanks for high and low voltage porcelain insulators, surge arrester porcelain components, or rod-shaped porcelain insulators for electrified railway lines, characterized in that... By adding corrective raw materials to stabilize the composition of the billet, and by controlling the aging time, the uniformity of the moisture content of the billet and the stability of its processing performance are ensured.

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