Novel white pigment porcelain white powder and preparation process thereof

Abstract

The invention discloses novel white pigment porcelain white powder which is prepared from the following raw materials: kaolin powder, silicon dioxide powder, metatitanic acid, nano aluminum oxide and an amino silane coupling agent. The novel white pigment porcelain white powder is prepared from the following raw materials in parts by weight: 11-12 parts of kaolin powder, 6-8 parts of silicon dioxide powder, 30 parts of metatitanic acid, 1 part of nano aluminum oxide and 0.4-0.5 part of an amino silane coupling agent. The kaolin powder and the silicon dioxide powder are used as main raw materials, metatitanic acid is used as an auxiliary material, and the use of full-dose titanium dioxide can be avoided, so that the advantages of high whiteness and low price of natural mineral resources can be fully utilized, the raw material expenditure is greatly reduced, meanwhile, the highest calcination temperature is controlled at 950 DEG C, and the energy consumption is reduced. The high-temperature process of the titanium dioxide is lower than that of the traditional titanium dioxide at 1000 DEG C or above, and is matched with a segmented temperature control strategy, so that the energy consumption is remarkably reduced, and

Description

Technical Field

[0001] This invention relates to the field of porcelain white powder processing technology, specifically to a novel white pigment porcelain white powder and its preparation process. Background Technology

[0002] White pigments are core raw materials for industries such as coatings, plastics, and papermaking. Among them, titanium dioxide has long dominated the mainstream market due to its excellent hiding power and whiteness. However, traditional titanium dioxide production processes have significant drawbacks: on the one hand, the sulfuric acid process or chloride process requires high temperature (above 1000℃) and strong acid and alkali treatment, which not only consumes a lot of energy but also generates a large amount of wastewater and waste gas, resulting in high environmental treatment costs and failing to meet the requirements of the national green and environmentally friendly industrial development outline; on the other hand, the cost of titanium dioxide raw materials is expensive, leading to high production costs for downstream enterprises, and there is an urgent need to find low-cost alternatives.

[0003] In existing technologies, kaolin and silica powder have been used to prepare white pigments due to their advantages such as high whiteness, stable chemical properties, and raw material costs that are only 1 / 3 to 1 / 2 that of titanium dioxide. However, these natural mineral-based pigments have fatal shortcomings: the particles are prone to agglomeration, resulting in poor dispersibility, and they lack the crystalline covering structure of titanium dioxide, with a covering power of only 60%-70% of that of titanium dioxide, which cannot meet the needs of mid-to-high-end applications. At the same time, the existing processes have vague parameter control over key steps such as grinding and calcination (e.g., the grinding media and heating rate are not clearly defined), resulting in large fluctuations in product performance, insufficient weather resistance and application adaptability, making it difficult to promote on a large scale. Therefore, we propose a new type of white pigment, porcelain white powder, and its preparation process. Summary of the Invention

[0004] The purpose of this invention is to provide a novel white pigment, porcelain white powder, and its preparation process, so as to solve the problems that need to be solved in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a novel white pigment, porcelain white powder, wherein the raw materials for manufacturing the novel white pigment porcelain white powder include kaolin powder, silica powder, metatitanic acid, nano alumina and aminosilane coupling agent, and the weight parts of the raw materials for manufacturing the novel white pigment porcelain white powder are 11-12 parts of kaolin powder, 6-8 parts of silica powder, 30 parts of metatitanic acid, 1 part of nano alumina and 0.4-0.5 parts of aminosilane coupling agent.

[0006] As a further description of the above technical solution:

[0007] The preparation process of the novel white pigment porcelain white powder includes the following steps:

[0008] Step 1: Raw material pretreatment. Select appropriate mass proportions of kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The kaolin powder has a whiteness of 95 and a diameter ≤5μm. The silica powder has a whiteness ≥98 and a diameter ≤5μm. The metatitanic acid has a purity ≥98% and is screened through a 200-mesh sieve. The nano-alumina has a particle size ≤200nm and a purity ≥99.5%.

[0009] Step 2: Add the same amount of pure water as the raw material pretreated in Step 1, mix the pure water and raw material evenly, and then pour the mixture into a ball mill. The ball mill has a linear speed of 200 m / min and a grinding time of 5-6 h. The slurry has a particle size distribution of 1.2-1.5 μm.

[0010] Step 3: Dewatering: Use a high-speed centrifuge to dewater the slurry from Step 2, so that the slurry moisture content is ≤8%;

[0011] Step 4: Drying and calcining modification: The dehydrated slurry is sent into a kiln for calcination treatment, and the kiln is used to carry out three-stage calcination modification.

[0012] Step 5: Crushing, grinding, and classifying: The large particles formed after calcination are crushed, then fed into a Raymond mill for grinding, and then classified by airflow to obtain uniform powder.

[0013] Step Six: Surface Treatment: Select the surface treatment method according to the product's intended use to obtain the finished porcelain white powder.

[0014] In existing technologies, kaolin and silica powder are being used to prepare white pigments due to their advantages such as high whiteness, stable chemical properties, and raw material costs that are only 1 / 3 to 1 / 2 of those of titanium dioxide. However, these natural mineral-based pigments have fatal shortcomings: the particles are prone to agglomeration, resulting in poor dispersibility, and they lack the crystalline covering structure of titanium dioxide, with a covering power of only 60%-70% of that of titanium dioxide, failing to meet the needs of mid-to-high-end applications. Furthermore, existing processes have vague parameter control over key steps such as grinding and calcination (e.g., unclear grinding media, heating rate), leading to large fluctuations in product performance, insufficient weather resistance and application adaptability, making large-scale promotion difficult. This invention, using kaolin powder and silica powder as main raw materials and metatitanic acid as an auxiliary material, avoids the use of all titanium dioxide. This setup fully utilizes the advantages of high whiteness and low price of natural mineral resources, significantly reducing raw material costs. Simultaneously, the maximum calcination temperature is controlled at 950℃, lower than the traditional high-temperature process of over 1000℃ for titanium dioxide. Combined with a segmented temperature control strategy, energy consumption is significantly reduced, and equipment wear is minimized. The porcelain white powder manufactured in this invention effectively compensates for the insufficient covering power of pure mineral pigments, and its nano-scale properties further enhance its effectiveness. The introduction of alumina not only enhances weather resistance and thermal stability but also naturally forms a hydrophilic alumina film in hydrophilic products, requiring no additional treatment. The added aminosilane coupling agent improves the interfacial bonding between inorganic fillers and organic matrices, enhancing compatibility and dispersion stability in coatings, plastics, and other systems. This invention avoids the strong acid and alkali, highly polluting sulfuric acid or chlorination processes used in traditional titanium dioxide production. It employs a water-based pulping system and electrically heated tunnel kiln calcination, resulting in clean and environmentally friendly processes without harmful waste gas or wastewater emissions. Furthermore, the precise three-stage drying and calcination modification parameters ensure optimized material structure and improved energy efficiency. Through surface treatment, hydrophilic and hydrophobic titanium dioxide can be prepared: the hydrophilic product is suitable for water-based coatings, papermaking, and other fields; the hydrophobic product, by adding 2% methyltrimethoxysilane and 1% polyoxyethylene polyoxypropylene ether block copolymer, achieves good hydrophobicity, making it suitable for oil-based systems and outdoor building materials.

[0015] As a further description of the above technical solution:

[0016] In step two, the grinding media inside the ball mill is zirconium beads with a diameter of 0.8-1.2 mm. An electric heating plate is installed outside the ball mill, and the slurry temperature is 25℃-35℃ during the grinding process.

[0017] As a further description of the above technical solution:

[0018] In step four, the kiln undergoes a three-stage calcination modification process. In the first stage, the kiln temperature is raised from room temperature to 400°C, and then held at 400°C for 60 minutes. In the second stage, the kiln temperature is raised from 400°C to 950°C for 20 minutes, and then held at 950°C for 120 minutes. In the third stage, the material is sent to a cooling box to rapidly cool down to 50°C.

[0019] As a further description of the above technical solution:

[0020] The kiln is an electrically heated tunnel kiln. The heating rate in the first stage of the electrically heated tunnel kiln is 5℃-6℃ / min. The third stage adopts forced convection cooling with a cooling wind speed of 3-5m / min, so that the material is cooled to below 50℃ within 30 minutes.

[0021] As a further description of the above technical solution:

[0022] The surface treatment method in step six includes preparing hydrophilic porcelain white powder and preparing hydrophobic porcelain white powder. When preparing the hydrophobic product, surface treatment is performed. During the surface treatment, 2% organosilicon and 1% surfactant are added to the uniform powder in step five by mass percentage. The organosilicon and surfactant are added in the form of solution or emulsion. After stirring and mixing, the finished porcelain white powder is obtained. When preparing the hydrophilic product, no surface treatment is required.

[0023] As a further description of the above technical solution:

[0024] When preparing the hydrophobic product, the surfactant is a polyoxyethylene polyoxypropylene ether block copolymer, the organosilicon is methyltrimethoxysilane, and the stirring speed is 600-800 r / min, and the stirring time is 30-40 min.

[0025] As a further description of the above technical solution:

[0026] Before mixing the raw materials in step two, the kaolin powder and silica powder are pre-dispersed. The pre-dispersion treatment is performed by ultrasonic dispersion, the ultrasonic power of which is 300-500W and the ultrasonic pre-dispersion time is 20-30min.

[0027] As a further description of the above technical solution:

[0028] The finished porcelain white powder is packaged using a vacuum packaging machine, and the packaging bag is a PE moisture-proof film packaging bag.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. First, by using kaolin powder and silica powder as the main raw materials and metatitanic acid as the auxiliary material, this invention can avoid using all of the titanium dioxide. This setup can make full use of the advantages of high whiteness and low price of natural mineral resources, significantly reducing raw material expenditure. At the same time, the maximum calcination temperature is controlled at 950℃, which is lower than the high temperature process of traditional titanium dioxide above 1000℃. Combined with the segmented temperature control strategy, energy consumption is significantly reduced and equipment wear is reduced.

[0031] 2. Secondly, the porcelain white powder manufactured in this invention effectively makes up for the lack of hiding power of pure mineral pigments. Furthermore, the introduction of nano alumina not only enhances weather resistance and thermal stability, but also naturally forms a hydrophilic alumina film in hydrophilic products without the need for additional treatment. The aminosilane coupling agent can improve the interfacial bonding between inorganic fillers and organic matrices, thereby enhancing compatibility and dispersion stability in coatings, plastics and other systems.

[0032] 3. Furthermore, the present invention avoids the strong acid and alkali, highly polluting sulfuric acid or chlorination process used in traditional titanium dioxide production during the manufacturing process. It adopts a water-based pulping system and an electrically heated tunnel kiln for calcination. This processing method will not produce harmful waste gas and wastewater emissions, and the process is clean and environmentally friendly. Moreover, the three-stage drying and calcination modification parameters are precise, which not only ensures the optimization of material structure but also improves energy utilization efficiency.

[0033] 4. Finally, through surface treatment steps, the product can be prepared into hydrophilic and hydrophobic porcelain white powders respectively: the hydrophilic product is suitable for water-based coatings, papermaking and other fields; the hydrophobic product, by adding 2% methyltrimethoxysilane and 1% polyoxyethylene polyoxypropylene ether block copolymer, obtains good hydrophobicity and is suitable for oil-based systems and outdoor building materials. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1:

[0036] This invention provides a technical solution: a novel white pigment, porcelain white powder, wherein the raw materials for manufacturing the novel white pigment porcelain white powder include kaolin powder, silica powder, metatitanic acid, nano alumina and aminosilane coupling agent, and the weight parts of the raw materials for manufacturing the novel white pigment porcelain white powder are 11-12 parts of kaolin powder, 6-8 parts of silica powder, 30 parts of metatitanic acid, 1 part of nano alumina and 0.4-0.5 parts of aminosilane coupling agent.

[0037] Among them, the raw materials for manufacturing porcelain white powder are mainly high-whiteness, low-cost kaolin and silica, with metatitanic acid as an auxiliary material. While significantly reducing the cost of raw materials, it retains the covering power and whiteness close to that of titanium dioxide. Nano alumina enhances the thermal stability and weather resistance of the powder, effectively improving the service life of the product in harsh environments. Aminosilane coupling agent improves the interfacial compatibility between inorganic particles and organic matrix, greatly improves dispersion stability, and prevents agglomeration.

[0038] Example 2:

[0039] The preparation process of the novel white pigment porcelain white powder includes the following steps:

[0040] Step 1: Raw material pretreatment. Select appropriate mass proportions of kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The kaolin powder has a whiteness of 95 and a diameter ≤5μm. The silica powder has a whiteness ≥98 and a diameter ≤5μm. The metatitanic acid has a purity ≥98% and is screened through a 200-mesh sieve. The nano-alumina has a particle size ≤200nm and a purity ≥99.5%.

[0041] Step 2: Add the same amount of pure water as the raw material pretreated in Step 1, mix the pure water and raw material evenly, and then pour the mixture into a ball mill. The ball mill has a linear speed of 200 m / min and a grinding time of 5-6 h. The slurry has a particle size distribution of 1.2-1.5 μm.

[0042] Step 3: Dewatering: Use a high-speed centrifuge to dewater the slurry from Step 2, so that the slurry moisture content is ≤8%;

[0043] Step 4: Drying and calcining modification: The dehydrated slurry is sent into a kiln for calcination treatment, and the kiln is used to carry out three-stage calcination modification.

[0044] Step 5: Crushing, grinding, and classifying: The large particles formed after calcination are crushed, then fed into a Raymond mill for grinding, and then classified by airflow to obtain uniform powder.

[0045] Step Six: Surface Treatment: Select the surface treatment method according to the product's intended use to obtain the finished porcelain white powder.

[0046] In the raw material pretreatment stage, the whiteness, particle size, and purity of each component are strictly limited. This ensures high whiteness, high purity, and good reactivity of the product from the selection of raw materials, avoiding impurities from interfering with subsequent calcination and phase formation. Secondly, the ball milling process uses specific linear speed conditions for 5-6 hours to precisely control the median particle size of the slurry to 1.2-1.5 μm, achieving highly uniform mixing and micronization of each component. This lays the foundation for uniform crystal phase development during subsequent calcination. The three-stage calcination modification not only promotes the conversion of metatitanic acid into a high-coverage titanium dioxide crystal phase, but also optimizes the composite particle structure and improves thermal stability and weather resistance. At the same time, the electrically heated tunnel kiln and precise heating and cooling rates ensure that the process is repeatable and has low fluctuations. This can effectively deagglomerate hard agglomerates after calcination, obtaining uniform powder with narrow particle size distribution and good flowability. Finally, surface treatment can give the product the ability to flexibly adapt to water-based or oil-based systems.

[0047] In step two, the grinding media inside the ball mill is zirconium beads with a diameter of 0.8-1.2 mm. An electric heating plate is installed outside the ball mill, and the slurry temperature is 25℃-35℃ during the grinding process.

[0048] Zirconium beads are used as the grinding media because of their high hardness, high density, and strong chemical inertness. They can effectively break and disperse raw material particles while avoiding the introduction of impurities and ensuring the high whiteness and purity of the porcelain white powder. The diameter of the zirconium beads is limited to ensure sufficient impact force while achieving fine grinding of micron-sized powders, preventing over-grinding or under-grinding, and improving the uniformity of particle size distribution. In addition, an electric heating plate is installed on the outside of the ball mill to effectively suppress the heat accumulation generated by long-term grinding, and avoid excessive local temperature that may cause premature hydrolysis, agglomeration of metatitanic acid, or failure of coupling agent, thereby ensuring the stable mixing of each component and the controllability of the subsequent calcination reaction.

[0049] In step four, the kiln undergoes a three-stage calcination modification process. In the first stage, the kiln temperature is raised from room temperature to 400°C, and then held at 400°C for 60 minutes. This slow heating process dehydrates the product. In the second stage, the kiln temperature is raised from 400°C to 950°C over a period of 20 minutes, and then held at 950°C for 120 minutes. In the third stage, the material is sent to a cooling box for rapid cooling to 50°C.

[0050] The first stage of calcination involves slow heating combined with heat preservation, which thoroughly removes physically adsorbed water, crystal water, and volatile byproducts that may be generated by aminosilane coupling agents at high temperatures from the raw materials. This prevents particle bursting, uneven porosity, or decreased whiteness due to sudden release of moisture or gas in subsequent high-temperature stages, thus ensuring the compactness and appearance quality of the powder structure. The second stage of calcination allows metatitanic acid to be fully dehydrated and transformed into anatase or rutile titanium dioxide with high refractive index, giving the product excellent hiding power. At the same time, kaolin, silica, and nano-alumina undergo interfacial solid-phase reaction at high temperatures to form a stable composite oxide structure. The rapid heating for 20 minutes helps to suppress excessive development of the mesophase, while the constant temperature for 120 minutes ensures sufficient reaction and uniform grain growth. The rapid cooling in the third stage effectively prevents titanium dioxide grain coarsening or phase transformation instability during slow cooling, maintaining high specific surface area and optical properties. At the same time, rapid cooling reduces sintering and agglomeration between particles, which is beneficial for subsequent crushing and dispersion, improving the flowability and application adaptability of the finished powder.

[0051] The kiln is an electrically heated tunnel kiln. The heating rate in the first stage of the electrically heated tunnel kiln is 5℃-6℃ / min. The third stage adopts forced convection cooling with a cooling wind speed of 3-5m / min, so that the material is cooled to below 50℃ within 30 minutes.

[0052] The process employs an electrically heated tunnel kiln as the calcination equipment. In the first stage, the temperature is slowly increased to 400℃ at a rate of 5℃-6℃ / min. This allows for the stable removal of moisture and organic components from the material, preventing particle cracking, powder splashing, or internal stress concentration caused by excessively rapid heating. This ensures the structural integrity and whiteness stability of the product. In the third stage, forced convection cooling with cold air is used, with the wind speed controlled at 3-5m / min. This ensures that the material is rapidly cooled to below 50℃ within 30 minutes. On the one hand, this effectively inhibits the excessive growth of titanium dioxide grains at high temperatures, maintaining a high specific surface area and excellent covering power. On the other hand, it prevents uneven crystal transformation or agglomeration hardening caused by slow cooling, thereby improving the dispersibility and subsequent processing performance of the powder.

[0053] The surface treatment method in step six includes preparing hydrophilic porcelain white powder and preparing hydrophobic porcelain white powder. In the preparation of the hydrophobic product, surface treatment is performed. During surface treatment, 2% organosilicon and 1% surfactant are added to the uniform powder from step five by mass percentage. The organosilicon and surfactant are added in solution or emulsion form. After stirring and mixing, the finished porcelain white powder is obtained, allowing the treatment agent molecules to be uniformly adsorbed or reacted on the particle surface. In the preparation of the hydrophilic product, since nano-alumina has been incorporated during the pulping process before calcination, the product itself has an alumina film with hydrophilicity, eliminating the need for surface treatment. This setup ensures that the finished porcelain white powder has both hydrophilic and hydrophobic properties, making it more adaptable. In the preparation of the hydrophobic product, the surfactant is a polyoxyethylene polyoxypropylene ether block copolymer, and the organosilicon is methyltrimethoxysilane. The stirring speed is 600-800 r / min, and the stirring time is 30-40 min.

[0054] Before mixing the raw materials in step two, the kaolin powder and silica powder are pre-dispersed. The pre-dispersion treatment is performed by ultrasonic dispersion, the ultrasonic power of which is 300-500W and the ultrasonic pre-dispersion time is 20-30min.

[0055] The pre-dispersion treatment is set before mixing raw materials. Kaolin powder and silica powder are subjected to ultrasonic pre-dispersion treatment, which can effectively break up the soft agglomerates formed by van der Waals forces or electrostatic effects during storage or transportation. This treatment significantly improves the initial dispersion state of the two inorganic powders in the subsequent aqueous slurry.

[0056] The finished porcelain white powder is packaged using a vacuum packaging machine, and the packaging bag is a PE moisture-proof film packaging bag.

[0057] Example 3:

[0058] A novel white pigment, porcelain white powder, is disclosed. The raw materials for manufacturing the novel white pigment, porcelain white powder, include kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The weight proportions of the raw materials for manufacturing the novel white pigment, porcelain white powder, are 11 parts kaolin powder, 6 parts silica powder, 30 parts metatitanic acid, 1 part nano-alumina, and 0.4 parts aminosilane coupling agent.

[0059] The preparation process of the novel white pigment porcelain white powder includes the following steps:

[0060] Step 1: Raw material pretreatment. Select appropriate mass proportions of kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The kaolin powder has a whiteness of 95 and a diameter ≤5μm. The silica powder has a whiteness ≥98 and a diameter ≤5μm. The metatitanic acid has a purity ≥98% and is screened through a 200-mesh sieve. The nano-alumina has a particle size ≤200nm and a purity ≥99.5%.

[0061] Step 2: Add the same amount of pure water as the raw materials pretreated in Step 1, mix the pure water and raw materials evenly, and then pour the mixture into a ball mill. The ball mill has a linear speed of 200 m / min, a grinding time of 5 h, and a slurry with a particle centerline of 1.2 μm.

[0062] Step 3: Dewatering: Use a high-speed centrifuge to dewater the slurry from Step 2, so that the slurry moisture content is ≤8%;

[0063] Step 4: Drying and calcining modification: The dehydrated slurry is sent into a kiln for calcination treatment, and the kiln is used to carry out three-stage calcination modification.

[0064] Step 5: Crushing, grinding, and classifying: The large particles formed after calcination are crushed, then fed into a Raymond mill for grinding, and then classified by airflow to obtain uniform powder.

[0065] Step Six: Surface Treatment: Select the surface treatment method according to the product's intended use to obtain the finished porcelain white powder.

[0066] In step two, the grinding media inside the ball mill is zirconium beads with a diameter of 0.8 mm. An electric heating plate is installed outside the ball mill, and the slurry temperature is 25°C during the grinding process.

[0067] In step four, the kiln undergoes a three-stage calcination modification process. In the first stage, the kiln temperature is raised from room temperature to 400°C, and then held at 400°C for 60 minutes. In the second stage, the kiln temperature is raised from 400°C to 950°C for 20 minutes, and then held at 950°C for 120 minutes. In the third stage, the material is sent to a cooling box to rapidly cool down to 50°C.

[0068] The kiln is an electrically heated tunnel kiln. The heating rate in the first stage of the electrically heated tunnel kiln is 5℃ / min. The third stage adopts forced convection cooling with a cooling wind speed of 3m / min, so that the material is cooled to below 50℃ within 30 minutes.

[0069] In the preparation of the hydrophobic product, the surfactant is a polyoxyethylene polyoxypropylene ether block copolymer, the organosilicon is methyltrimethoxysilane, and the stirring speed is 600 r / min and the stirring time is 30-40 min.

[0070] Before mixing the raw materials in step two, the kaolin powder and silica powder are pre-dispersed. The pre-dispersion treatment is performed by ultrasonic dispersion, the ultrasonic power of which is 300W and the ultrasonic pre-dispersion time is 20min.

[0071] Example 4:

[0072] A novel white pigment, porcelain white powder, is disclosed. The raw materials for manufacturing the novel white pigment, porcelain white powder, include kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The weight proportions of the raw materials for manufacturing the novel white pigment, porcelain white powder, are 12 parts kaolin powder, 8 parts silica powder, 30 parts metatitanic acid, 1 part nano-alumina, and 0.5 parts aminosilane coupling agent.

[0073] The preparation process of the novel white pigment porcelain white powder includes the following steps:

[0074] Step 1: Raw material pretreatment. Select appropriate mass proportions of kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The kaolin powder has a whiteness of 95 and a diameter ≤5μm. The silica powder has a whiteness ≥98 and a diameter ≤5μm. The metatitanic acid has a purity ≥98% and is screened through a 200-mesh sieve. The nano-alumina has a particle size ≤200nm and a purity ≥99.5%.

[0075] Step 2: Add the same amount of pure water as the raw materials pretreated in Step 1, mix the pure water and raw materials evenly, and then pour the mixture into a ball mill. The ball mill has a linear speed of 200 m / min, a grinding time of 6 h, and a slurry with a particle size of 1.5 μm.

[0076] Step 3: Dewatering: Use a high-speed centrifuge to dewater the slurry from Step 2, so that the slurry moisture content is ≤8%;

[0077] Step 4: Drying and calcining modification: The dehydrated slurry is sent into a kiln for calcination treatment, and the kiln is used to carry out three-stage calcination modification.

[0078] Step 5: Crushing, grinding, and classifying: The large particles formed after calcination are crushed, then fed into a Raymond mill for grinding, and then classified by airflow to obtain uniform powder.

[0079] Step Six: Surface Treatment: Select the surface treatment method according to the product's intended use to obtain the finished porcelain white powder.

[0080] In step two, the grinding media inside the ball mill is zirconium beads with a diameter of 1.2 mm. An electric heating plate is installed outside the ball mill, and the slurry temperature is 35°C during the grinding process.

[0081] In step four, the kiln undergoes a three-stage calcination modification process. In the first stage, the kiln temperature is raised from room temperature to 400°C, and then held at 400°C for 60 minutes. In the second stage, the kiln temperature is raised from 400°C to 950°C for 20 minutes, and then held at 950°C for 120 minutes. In the third stage, the material is sent to a cooling box to rapidly cool down to 50°C.

[0082] The kiln is an electrically heated tunnel kiln. The heating rate in the first stage of the electrically heated tunnel kiln is 6℃ / min. The third stage adopts forced convection cooling with a cooling wind speed of 5m / min, so that the material is cooled to below 50℃ within 30 minutes.

[0083] In the preparation of the hydrophobic product, the surfactant is a polyoxyethylene polyoxypropylene ether block copolymer, the organosilicon is methyltrimethoxysilane, and the stirring speed is 800 r / min and the stirring time is 40 min.

[0084] Before mixing the raw materials in step two, the kaolin powder and silica powder are pre-dispersed. The pre-dispersion treatment is performed by ultrasonic dispersion, the ultrasonic power of which is 500W and the ultrasonic pre-dispersion time is 30min.

[0085] Example 5:

[0086] A novel white pigment, porcelain white powder, is disclosed. The raw materials for manufacturing the novel white pigment, porcelain white powder, include kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The weight proportions of the raw materials for manufacturing the novel white pigment, porcelain white powder, are 11.5 parts kaolin powder, 7 parts silica powder, 30 parts metatitanic acid, 1 part nano-alumina, and 0.45 parts aminosilane coupling agent.

[0087] The preparation process of the novel white pigment porcelain white powder includes the following steps:

[0088] Step 1: Raw material pretreatment. Select appropriate mass proportions of kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The kaolin powder has a whiteness of 95 and a diameter ≤5μm. The silica powder has a whiteness ≥98 and a diameter ≤5μm. The metatitanic acid has a purity ≥98% and is screened through a 200-mesh sieve. The nano-alumina has a particle size ≤200nm and a purity ≥99.5%.

[0089] Step 2: Add the same amount of pure water as the raw materials pretreated in Step 1, mix the pure water and raw materials evenly, and then pour the mixture into a ball mill. The ball mill has a linear speed of 200 m / min, a grinding time of 5.5 h, and a slurry with a particle centerline of 1.35 μm.

[0090] Step 3: Dewatering: Use a high-speed centrifuge to dewater the slurry from Step 2, so that the slurry moisture content is ≤8%;

[0091] Step 4: Drying and calcining modification: The dehydrated slurry is sent into a kiln for calcination treatment, and the kiln is used to carry out three-stage calcination modification.

[0092] Step 5: Crushing, grinding, and classifying: The large particles formed after calcination are crushed, then fed into a Raymond mill for grinding, and then classified by airflow to obtain uniform powder.

[0093] Step Six: Surface Treatment: Select the surface treatment method according to the product's intended use to obtain the finished porcelain white powder.

[0094] In step two, the grinding media inside the ball mill is zirconium beads with a diameter of 1 mm. An electric heating plate is installed outside the ball mill, and the slurry temperature is 30°C during the grinding process.

[0095] In step four, the kiln undergoes a three-stage calcination modification process. In the first stage, the kiln temperature is raised from room temperature to 400°C, and then held at 400°C for 60 minutes. In the second stage, the kiln temperature is raised from 400°C to 950°C for 20 minutes, and then held at 950°C for 120 minutes. In the third stage, the material is sent to a cooling box to rapidly cool down to 50°C.

[0096] The kiln is an electrically heated tunnel kiln. The heating rate in the first stage of the electrically heated tunnel kiln is 5℃ / min. The third stage adopts forced convection cooling with a cooling wind speed of 4m / min, so that the material is cooled to below 50℃ within 30 minutes.

[0097] In the preparation of the hydrophobic product, the surfactant is a polyoxyethylene polyoxypropylene ether block copolymer, the organosilicon is methyltrimethoxysilane, and the stirring speed is 700 r / min and the stirring time is 35 min.

[0098] Before mixing the raw materials in step two, the kaolin powder and silica powder are pre-dispersed. The pre-dispersion treatment is performed by ultrasonic dispersion, the ultrasonic power of which is 400W and the ultrasonic pre-dispersion time is 25min.

[0099] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel white pigment, porcelain white powder, characterized in that: The raw materials for manufacturing the novel white pigment porcelain white powder include kaolin powder, silica powder, metatitanic acid, nano alumina, and aminosilane coupling agent. The weight proportions of the raw materials for manufacturing the novel white pigment porcelain white powder are 11-12 parts of kaolin powder, 6-8 parts of silica powder, 30 parts of metatitanic acid, 1 part of nano alumina, and 0.4-0.5 parts of aminosilane coupling agent.

2. A preparation process for a novel white pigment, porcelain white powder, applicable to the novel white pigment porcelain white powder as described in claim 1, characterized in that: The preparation process of the novel white pigment porcelain white powder includes the following steps: Step 1: Raw material pretreatment. Select appropriate mass proportions of kaolin powder, silica powder, metatitanic acid, nano-alumina, and aminosilane coupling agent. The kaolin powder has a whiteness of 95 and a diameter ≤5μm. The silica powder has a whiteness ≥98 and a diameter ≤5μm. The metatitanic acid has a purity ≥98% and is screened through a 200-mesh sieve. The nano-alumina has a particle size ≤200nm and a purity ≥99.5%. Step 2: Add the same amount of pure water as the raw material pretreated in Step 1, mix the pure water and raw material evenly, and then pour the mixture into a ball mill. The ball mill has a linear speed of 200 m / min and a grinding time of 5-6 h. The slurry has a particle size distribution of 1.2-1.5 μm. Step 3: Dewatering: Use a high-speed centrifuge to dewater the slurry from Step 2, so that the slurry moisture content is ≤8%; Step 4: Drying and calcining modification: The dehydrated slurry is sent into a kiln for calcination treatment, and the kiln is used to carry out three-stage calcination modification. Step 5: Crushing, grinding, and classifying: The large particles formed after calcination are crushed, then fed into a Raymond mill for grinding, and then classified by airflow to obtain uniform powder. Step Six: Surface Treatment: Select the surface treatment method according to the product's intended use to obtain the finished porcelain white powder.

3. The preparation process of a novel white pigment, porcelain white powder, according to claim 1, is characterized in that: In step two, the grinding media inside the ball mill is zirconium beads with a diameter of 0.8-1.2 mm. An electric heating plate is installed outside the ball mill, and the slurry temperature is 25℃-35℃ during the grinding process.

4. The preparation process of a novel white pigment, porcelain white powder, according to claim 3, is characterized in that: In step four, the kiln undergoes a three-stage calcination treatment for modification. The first stage of calcination treatment involves raising the kiln temperature from room temperature to 400°C, and then holding the kiln at 400°C for 60 minutes. In the second stage, the kiln temperature is raised from 400℃ to 950℃ over a period of 20 minutes, and then kept constant at 950℃ for 120 minutes. In the third stage, the material is sent to a cooling box to cool down rapidly to 50℃.

5. The preparation process of a novel white pigment, porcelain white powder, according to claim 4, is characterized in that: The kiln is an electrically heated tunnel kiln. The heating rate in the first stage of the electrically heated tunnel kiln is 5℃-6℃ / min. The third stage adopts forced convection cooling with a cooling wind speed of 3-5m / min, so that the material is cooled to below 50℃ within 30 minutes.

6. The preparation process of a novel white pigment, porcelain white powder, according to claim 5, is characterized in that: The surface treatment method in step six includes preparing hydrophilic porcelain white powder and preparing hydrophobic porcelain white powder. When preparing the hydrophobic product, surface treatment is performed. During the surface treatment, 2% organosilicon and 1% surfactant are added to the uniform powder in step five by mass percentage. The organosilicon and surfactant are added in the form of solution or emulsion. After stirring and mixing, the finished porcelain white powder is obtained. When preparing the hydrophilic product, no surface treatment is required.

7. The preparation process of a novel white pigment, porcelain white powder, according to claim 6, is characterized in that: When preparing the hydrophobic product, the surfactant is a polyoxyethylene polyoxypropylene ether block copolymer, the organosilicon is methyltrimethoxysilane, and the stirring speed is 600-800 r / min, and the stirring time is 30-40 min.

8. The preparation process of a novel white pigment, porcelain white powder, according to claim 7, is characterized in that: Before mixing the raw materials in step two, the kaolin powder and silica powder are pre-dispersed. The pre-dispersion treatment is performed by ultrasonic dispersion, the ultrasonic power of which is 300-500W and the ultrasonic pre-dispersion time is 20-30min.

9. The preparation process of a novel white pigment, porcelain white powder, according to claim 8, characterized in that: The finished porcelain white powder is packaged using a vacuum packaging machine, and the packaging bag is a PE moisture-proof film packaging bag.