Super-white superfine barite powder, and preparation method and application thereof

Abstract

This invention belongs to the field of inorganic non-metallic materials technology, and provides an ultra-white, ultra-fine barite powder, its preparation method, and its application. The preparation method of the ultra-white, ultra-fine barite powder of this invention includes the following steps: sequentially subjecting coarse barite powder to gravity separation, dry grinding, magnetic separation, wet ball milling, and air classification to obtain the ultra-white, ultra-fine barite powder. The ultra-white, ultra-fine barite powder prepared by this invention, when applied to white ABS plastic, can replace 10-30% of the amount of titanium dioxide used, saving production costs for downstream products while maintaining good impact resistance.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic materials technology, and in particular to an ultra-white ultrafine barite powder, its preparation method, and its application. Background Technology

[0002] ABS (acrylonitrile-butadiene-styrene) plastic has excellent dimensional stability and chemical resistance, as well as good impact strength and excellent heat resistance. It is widely used in the housing materials of electrical and electronic equipment.

[0003] Titanium dioxide (especially rutile titanium dioxide) is currently the highest-performing white pigment in the ABS plastics industry, but its price fluctuates significantly due to factors such as titanium ore resources and environmental policies, and its unit cost is relatively high (typically 3 to 5 times that of barium sulfate). In the production and processing of ABS (acrylonitrile-butadiene-styrene copolymer) plastics, replacing titanium dioxide with barium sulfate is a common formulation optimization method in the industry, with its significance mainly reflected in multiple dimensions such as cost control, performance adjustment, environmental compliance, and supply chain stability.

[0004] To maintain high impact resistance in applications, ABS plastic requires the addition of ultrafine barium sulfate particles to better preserve its impact performance. At the same time, to maintain color stability after adding fillers, barium sulfate with high whiteness and purity is required.

[0005] Therefore, it is of great significance to study an ultra-white and ultra-fine barite powder, its preparation method and application, in order to reduce the production cost of modified ABS plastic. Summary of the Invention

[0006] The purpose of this invention is to provide an ultra-white, ultra-fine barite powder, its preparation method, and its application, thereby solving the problems of large particle size and low whiteness of barite powder in the prior art.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing ultra-white and ultra-fine barite powder, the method comprising the following steps: sequentially subjecting coarse barite powder to gravity separation, dry grinding, magnetic separation, wet ball milling and air classification to obtain ultra-white and ultra-fine barite powder.

[0008] Preferably, the particle size of the barite coarse powder is 0.5~1cm; The gravity separation involves feeding barite coarse powder to a jig for gravity separation to obtain concentrate. The density of the concentrate is ≥4.2 g / cm³. 3 .

[0009] Preferably, the fineness D97 of the product after dry grinding is 20~30μm; The magnetic separation is carried out in a dry magnetic separator.

[0010] Preferably, in the wet ball milling, the grinding media is ceramic balls, the grinding liner is ceramic brick, the grinding time is 30~80min, and the grinding speed is 14~30rpm.

[0011] Preferably, during the wet ball milling process, an aqueous solution containing a dispersant is added, and the amount of the aqueous solution containing the dispersant added is 80~150L / h; The dispersant is one or more of sodium polyacrylate, polyacrylamide, polyacrylic acid, and polyethylene glycol; The concentration of the dispersant in the aqueous solution is 5-12 wt%.

[0012] Preferably, in the air classification process, the classifier rotates at a speed of 2000~4000 rpm, and the number of classifying wheels in the classifier is 3~6.

[0013] The present invention also provides a method for preparing ultra-white ultrafine barite powder, which yields ultra-white ultrafine barite powder.

[0014] Preferably, the ultra-white ultrafine barite powder has a D50 of 1.2~1.5μm, a D97 of 3.5~4μm, a whiteness ≥94.5, and a barium sulfate content ≥94.5%.

[0015] The present invention also provides the application of the ultra-white ultrafine barite powder in ABS plastic to partially replace titanium dioxide.

[0016] Preferably, the amount of ultra-white ultrafine barite powder replacing titanium dioxide is 10~30wt%.

[0017] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: In the purification of raw ore, this invention employs gravity separation to obtain ore with a specific gravity ≥ 4.2 g / cm³. 3 The process involves obtaining the concentrate; simultaneously, combining this with magnetic separation to separate magnetic minerals from the concentrate, thereby increasing the purity of the raw ore and raising the barium sulfate content in barite to ≥94.5%. Compared with traditional barite acid washing and purification processes, the process of this invention has advantages such as energy saving and environmental protection, simple process flow, and ease of large-scale production.

[0018] In order to avoid introducing other impurities during the physical grinding process, the wet ball milling media of this invention is changed from steel balls to ceramic balls, and wear-resistant ceramic bricks are laid in full dimensions on the inner lining of the grinding cylinder; this solves the problem of introducing impurities and reducing product purity during the traditional physical grinding process.

[0019] The innovation in ultrafine processing in this invention is mainly the use of wet grinding combined with air classification, which realizes continuous closed production and improves production efficiency; through continuous air classification, the prepared barium sulfate particles are fine in size and narrow in distribution.

[0020] The ultra-white, ultra-fine barite powder prepared by this invention can replace 10-30% of titanium dioxide in white ABS plastic, saving production costs for downstream products while maintaining good impact resistance. Detailed Implementation

[0021] This invention provides a method for preparing ultra-white and ultra-fine barite powder, the method comprising the following steps: sequentially subjecting coarse barite powder to gravity separation, dry grinding, magnetic separation, wet ball milling and air classification to obtain ultra-white and ultra-fine barite powder.

[0022] In this invention, the barite coarse powder is preferably made by sequentially crushing and washing the raw barite ore before gravity separation.

[0023] In this invention, the barite ore contains preferably ≥90% barium sulfate, more preferably ≥91%, and even more preferably ≥91.5% barium sulfate.

[0024] In this invention, the crushing process preferably involves crushing the raw barite ore into blocks using a jaw crusher, and then further crushing the blocks into coarse particles using a hammer crusher. The size of the block is preferably 2-5 cm, more preferably 2.5-4.5 cm, and even more preferably 3-4 cm. The particle size of the coarse particles is preferably 0.5-1 cm, more preferably 0.6-0.9 cm, and even more preferably 0.7-0.8 cm.

[0025] In this invention, the cleaning process is preferably carried out by using a horizontal drum cleaning machine to clean the coarse particles, thereby obtaining barite coarse powder.

[0026] In this invention, the particle size of the barite coarse powder is preferably 0.5~1cm, more preferably 0.6~0.9cm, and even more preferably 0.7~0.8cm.

[0027] In this invention, the gravity separation involves feeding barite coarse powder to a jig for gravity separation to obtain a concentrate; The density of the concentrate is preferably ≥4.2 g / cm³. 3 Further preferred is ≥4.25g / cm³ 3 More preferably ≥4.3g / cm 3 .

[0028] The magnetic separation is preferably carried out in a dry magnetic separator.

[0029] In this invention, the dry grinding is preferably carried out in an Yifeng mill, and the dry grinding product is obtained after grinding. The rotation speed of the dry grinding is preferably 1000~1200 rpm, more preferably 1050~1150 rpm, and even more preferably 1100~1120 rpm. The fineness D97 of the dry grinding product is preferably 20~30 μm, more preferably 22~28 μm, and even more preferably 24~26 μm.

[0030] In this invention, the purpose of magnetic separation is to separate magnetic minerals from barite and further improve its purity.

[0031] In this invention, the grinding medium in the wet ball mill is preferably ceramic balls, the grinding liner is preferably ceramic bricks, the grinding time is preferably 30-80 min, more preferably 40-70 min, more preferably 50-60 min, and the grinding speed is preferably 14-30 rpm, more preferably 16-26 rpm, more preferably 20-24 rpm.

[0032] In this invention, during the wet ball milling process, it is preferable to add an aqueous solution containing a dispersant. The amount of the aqueous solution containing the dispersant added is preferably 80~150L / h, more preferably 90~140L / h, and even more preferably 100~120L / h. The dispersant is preferably one or more of sodium polyacrylate, polyacrylamide, polyacrylic acid, and polyethylene glycol; In the aqueous solution containing the dispersant, the concentration of the dispersant is preferably 5-12 wt%, more preferably 6-10 wt%, and even more preferably 7-8 wt%.

[0033] In this invention, in the air classification process, the rotation speed of the classifier is preferably 2000~4000 rpm, more preferably 2500~3500 rpm, and even more preferably 3000~3200 rpm. The number of classifying wheels in the classifier is preferably 3~6, ​​and more preferably 4~5. In the air separation and grading process, the current of the induced draft fan used is preferably 100A.

[0034] In this invention, wet ball milling is used to achieve ultrafine preparation. The particle size is controlled by the rotation speed of the classifier. Particles with a fineness D50 ≤ 1.7 μm are classified by the classifier and then enter the packaging process. Particles with a fineness D50 > 1.7 μm are returned to the wet ball mill by the classifier for re-grinding. This process is a continuous cycle.

[0035] The present invention also provides a method for preparing ultra-white ultrafine barite powder, which yields ultra-white ultrafine barite powder.

[0036] In this invention, the D50 of the ultra-white ultrafine barite powder is preferably 1.2~1.5μm, more preferably 1.25~1.45μm, and even more preferably 1.3~1.4μm; the D97 is preferably 3.5~4μm, more preferably 3.6~3.9μm, and even more preferably 3.7~3.8μm; the whiteness is preferably ≥94.5, more preferably ≥95, and even more preferably ≥95.5; and the barium sulfate content is preferably ≥94.5%, more preferably ≥95%, and even more preferably ≥95.5%.

[0037] The present invention also provides the application of the ultra-white ultrafine barite powder in ABS plastic to partially replace titanium dioxide.

[0038] In this invention, the amount of ultra-white ultrafine barite powder replacing titanium dioxide is preferably 10-30 wt%, more preferably 15-25 wt%, and even more preferably 20-22 wt%.

[0039] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0040] In this embodiment of the invention, the reselection uses an AM30 jig. The dry grinding process uses a Yifeng YFM-318-3C mill. The ball mill used for wet grinding has a diameter of 1830 mm and a length of 7000 mm. The grinding media is ceramic balls, and the grinding lining is ceramic bricks. The air classifier is a fine classifier, and the diameter of the classifying wheel in the fine classifier is 325mm; ABS: Produced by Ningbo LG Yongxing Chemical Co., Ltd., model number "HI-121H"; EBS: Manufactured by Shanghai Kao Corporation, model number "EB-FF"; Zinc stearate: Produced by Dongguan Hanwei Technology Co., Ltd., model number "AV320"; Antioxidant 1010: Produced by BASF China Ltd.; Stearic acid: Produced by Hangzhou Oil & Fat Chemical Co., Ltd., model number "SA1840"; Titanium dioxide: Produced by DuPont, model number "R902".

[0041] In this embodiment of the invention, the method for preparing the barite coarse powder is as follows: Barite ore with a barium sulfate content of 92% is crushed into blocks of 2-5 cm in size using a jaw crusher. Then, a hammer crusher is used to crush the blocks into coarse particles of 0.5-1 cm in size. The coarse particles are then washed using a horizontal drum washer to obtain barite coarse powder.

[0042] Example 1

[0043] Weigh 40 kg of sodium polyacrylate, 40 kg of polyethylene glycol and 1000 L of water, put them into a mixing tank, and stir at 60 rpm for 45 min to obtain an aqueous solution containing the dispersant. The coarse barite powder was fed into a jig for gravity separation, yielding a sample with a specific gravity of 4.2 g / cm³. 3 The concentrate was then sent to the Yifeng mill for dry grinding at a speed of 1000 rpm. After grinding, a product with a D97 of 25 μm was obtained. The product was then subjected to magnetic separation to obtain the magnetically separated product. The magnetically separated product is fed into a ball mill for wet ball milling. During the ball milling process, 100 L / h of an aqueous solution containing a dispersant is added, the grinding time is 45 min, and the ball mill speed is 20 rpm. The ball-milled powder is then fed into a fine classifier consisting of four classifying wheels with a diameter of 325 mm for air classification. The classifier speed is 2800 rpm, and the current of the induced draft fan is 100 A. After classification, ultra-white ultrafine barite powder is obtained.

[0044] Example 2

[0045] Weigh 80 kg of sodium polyacrylate and 1000 L of water, put them into a mixing tank, and stir at 60 rpm for 45 min to obtain an aqueous solution containing the dispersant. The coarse barite powder was fed into a jig for gravity separation, yielding a sample with a specific gravity of 4.2 g / cm³. 3 The concentrate was then sent to the Yifeng mill for dry grinding at a speed of 1200 rpm. After grinding, a product with a D97 of 25 μm was obtained. The product was then subjected to magnetic separation to obtain the magnetically separated product. The magnetically separated product is fed into a ball mill for wet ball milling. During the ball milling process, 100 L / h of an aqueous solution containing a dispersant is added, the grinding time is 60 min, and the ball mill speed is 24 rpm. The ball-milled powder is then fed into a fine classifier consisting of four classifying wheels with a diameter of 325 mm for air classification. The classifier speed is 2800 rpm, and the current of the induced draft fan is 100 A. After classification, ultra-white ultrafine barite powder is obtained.

[0046] Example 3

[0047] Weigh 40 kg of sodium polyacrylate, 40 kg of polyacrylamide and 1000 L of water, put them into a mixing tank, and stir at 60 rpm for 45 min to obtain an aqueous solution containing the dispersant. The coarse barite powder was fed into a jig for gravity separation, yielding a sample with a specific gravity of 4.2 g / cm³. 3The concentrate was then sent to the Yifeng mill for dry grinding at a speed of 1100 rpm. After grinding, a product with a D97 of 25 μm was obtained. The product was then subjected to magnetic separation to obtain the magnetically separated product. The magnetically separated product is fed into a ball mill for wet ball milling. During the ball milling process, 100 L / h of an aqueous solution containing a dispersant is added, the grinding time is 45 min, and the ball mill speed is 24 rpm. The ball-milled powder is then fed into a fine classifier consisting of four classifying wheels with a diameter of 325 mm for air classification. The classifier speed is 3000 rpm, and the current of the induced draft fan is 100 A. After classification, ultra-white ultrafine barite powder is obtained.

[0048] Example 4

[0049] Weigh 40 kg of sodium polyacrylate, 40 kg of polyacrylamide and 1000 L of water, put them into a mixing tank, and stir at 60 rpm for 45 min to obtain an aqueous solution containing the dispersant. The coarse barite powder was fed into a jig for gravity separation, yielding a sample with a specific gravity of 4.2 g / cm³. 3 The concentrate was then sent to the Yifeng mill for dry grinding at a speed of 1200 rpm. After grinding, a product with a D97 of 25 μm was obtained. The product was then subjected to magnetic separation to obtain the magnetically separated product. The magnetically separated product is fed into a ball mill for wet ball milling. During the ball milling process, an aqueous solution containing a dispersant is added at a rate of 80 L / h, the grinding time is 45 min, and the ball mill speed is 30 rpm. The ball-milled powder is then fed into a fine classifier consisting of four classifying wheels with a diameter of 325 mm for air classification. The classifier speed is 3000 rpm, and the current of the induced draft fan is 100 A. After classification, ultra-white ultrafine barite powder is obtained.

[0050] Example 5

[0051] Weigh 40 kg of sodium polyacrylate, 20 kg of polyacrylamide, 20 kg of polyethylene glycol and 1000 L of water, put them into a mixing tank, and stir at 60 rpm for 45 min to obtain an aqueous solution containing dispersant. The coarse barite powder was fed into a jig for gravity separation, yielding a sample with a specific gravity of 4.2 g / cm³. 3 The concentrate was then sent to the Yifeng mill for dry grinding at a speed of 1000 rpm. After grinding, a product with a D97 of 25 μm was obtained. The product was then subjected to magnetic separation to obtain the magnetically separated product. The magnetically separated product is fed into a ball mill for wet ball milling. During the ball milling process, an aqueous solution containing a dispersant is added at a rate of 120 L / h, the grinding time is 60 min, and the ball mill speed is 30 rpm. The ball-milled powder is then fed into a fine classifier consisting of four classifying wheels with a diameter of 325 mm for air classification. The classifier speed is 3000 rpm, and the current of the induced draft fan is 100 A. After classification, ultra-white ultra-fine barite powder is obtained.

[0052] Example 6

[0053] Weigh 40 kg of sodium polyacrylate, 20 kg of polyacrylamide, 20 kg of polyethylene glycol and 1000 L of water, put them into a mixing tank, and stir at 60 rpm for 45 min to obtain an aqueous solution containing dispersant. The coarse barite powder was fed into a jig for gravity separation, yielding a sample with a specific gravity of 4.2 g / cm³. 3 The concentrate was then sent to the Yifeng mill for dry grinding at a speed of 1000 rpm. After grinding, a product with a D97 of 25 μm was obtained. The product was then subjected to magnetic separation to obtain the magnetically separated product. The magnetically separated product is fed into a ball mill for wet ball milling. During the ball milling process, 100 L / h of an aqueous solution containing a dispersant is added, the grinding time is 45 min, and the ball mill speed is 24 rpm. The ball-milled powder is then fed into a fine classifier consisting of four classifying wheels with a diameter of 325 mm for air classification. The classifier speed is 3000 rpm, and the current of the induced draft fan is 100 A. After classification, ultra-white ultrafine barite powder is obtained.

[0054] Comparative Example 1

[0055] Barium sulfate produced by physical methods, ultrafine barium sulfate produced by Jiangxi Guangyuan Chemical Co., Ltd., is product model "GC-3000".

[0056] Comparative Example 2

[0057] Barium sulfate prepared by precipitation method, and modified plastic-specific barium sulfate produced by Andeli New Materials Co., Ltd.

[0058] Comparative Example 3

[0059] Enriched precipitate of barium sulfate.

[0060] The ultra-white ultrafine barite powders obtained in Examples 1-6 and the barium sulfate described in Comparative Examples 1-3 were subjected to the following performance tests, and the test results are shown in Table 1: Particle size distribution: Particle size was measured using a BT-9300ST laser particle size analyzer from Liaoning Dandong Better Co., Ltd., where D50 represents the particle size value corresponding to a cumulative distribution of 50%; D97 represents the particle size value corresponding to a cumulative distribution of 97%. Whiteness: Whiteness was tested using a YQ-Z-48B whiteness meter from China Building Materials Intelligent Automation Research Institute Co., Ltd. Barium sulfate content: The barium sulfate content was tested according to GB / T37041-2018.

[0061] Table 1. Performance test results of the ultra-white ultrafine barite powder obtained in Examples 1-6 and the barium sulfate described in Comparative Examples 1-3.

[0062] As shown in Table 1, the ultra-white ultrafine barite powders prepared in Examples 1 to 6 have a D50 of 1.2 to 1.5 μm, a D97 of 3.5 to 4 μm, a whiteness of ≥94.5, and a barium sulfate content of ≥94.5%.

[0063] Compared with barium sulfate prepared by traditional physical grinding processes (Comparative Example 1), the ultra-white ultrafine barite powder obtained by this invention has a finer particle size, higher whiteness, and higher barium sulfate content. Compared with barium sulfate prepared by precipitation (Comparative Examples 2 and 3), the product prepared by the physical and chemical methods of this invention can achieve or even exceed the standards of precipitated barium sulfate in terms of particle size, while its whiteness and barium sulfate content are lower than those of precipitated barium sulfate.

[0064] The ultra-white, ultra-fine barite powder produced by this invention has its core application in ABS plastics, where it can partially replace titanium dioxide and also replace precipitated barium sulfate in the original formulation. Compared to the cumbersome and costly precipitated barium sulfate process (Comparative Examples 2 and 3), this invention effectively maintains the mechanical properties of the material while reducing formulation costs, thus solving the technical pain point of traditional precipitated barium sulfate in balancing cost control and performance.

[0065] In Application Examples 1-8 and Comparative Example 2 of this invention, the barium sulfate used was the ultra-white ultrafine barite powder obtained in Example 4.

[0066] Application Example 1

[0067] Raw materials and dosage: 2kg ABS, 80g ethylene glycol fatty ether stearate (EBS), 6g antioxidant 1010, 100g zinc stearate, 12g stearic acid, 360g titanium dioxide and 40g barium sulfate; Preparation method: Weigh all raw materials according to the formula. Set the high-speed mixer temperature to 105℃. Once the temperature is reached, pour all raw materials into the high-speed mixer and mix for 10 minutes. Then, pour the uniformly mixed material into the hopper of a twin-screw extruder. Set the extruder temperature to 230~250℃, with the principle of setting the temperature in the middle as higher and the two ends as lower. After the temperature stabilizes, use the twin-screw extruder to extrude and granulate the raw material. Put the granulated particles into an injection molding machine. Set the injection molding machine temperature to 220~240℃ and injection mold the particles to form the final product.

[0068] Application Example 2

[0069] Replace “360g titanium dioxide and 40g barium sulfate” in Application Example 1 with “340g titanium dioxide and 60g barium sulfate”, and follow the same steps as in Application Example 1.

[0070] Application Example 3

[0071] Replace “360g titanium dioxide and 40g barium sulfate” in Application Example 1 with “320g titanium dioxide and 80g barium sulfate”, and follow the same steps as in Application Example 1.

[0072] Application Example 4

[0073] Replace “360g titanium dioxide and 40g barium sulfate” in Application Example 1 with “300g titanium dioxide and 100g barium sulfate”, and follow the same steps as in Application Example 1.

[0074] Application Example 5

[0075] Replace “360g titanium dioxide and 40g barium sulfate” in Application Example 1 with “280g titanium dioxide and 120g barium sulfate”, and follow the same steps as in Application Example 1.

[0076] Application Example 6

[0077] Replace “360g titanium dioxide and 40g barium sulfate” in Application Example 1 with “260g titanium dioxide and 140g barium sulfate”, and follow the same steps as in Application Example 1.

[0078] Application Example 7

[0079] Replace “360g titanium dioxide and 40g barium sulfate” in Application Example 1 with “240g titanium dioxide and 160g barium sulfate”, and follow the same steps as in Application Example 1.

[0080] Application Example 8

[0081] Replace “360g titanium dioxide and 40g barium sulfate” in Application Example 1 with “220g titanium dioxide and 180g barium sulfate”, and follow the same steps as in Application Example 1.

[0082] Application Comparative Example 1

[0083] Replace the components in the raw materials and dosage in Application Example 1 with the same mass of ABS, and follow the same steps as in Application Example 1.

[0084] Application Comparative Example 2

[0085] Replace “360g titanium dioxide and 40g barium sulfate” in Application Example 1 with “400g titanium dioxide”, and follow the same steps as in Application Example 1.

[0086] The products obtained from corresponding use cases 1-8 and application comparison cases 1-2 were subjected to the following performance tests, and the test results are shown in Table 2: Color difference: Tested according to GB / T3979-2008 "Methods for measuring the color of objects" using a CS-826 benchtop spectrophotometer from Hangzhou Caipu Technology Co., Ltd. During the test, a sample with 400g of titanium dioxide added was used as the standard sample. The color performance difference between samples with different amounts of barium sulfate partially replacing titanium dioxide and samples with only titanium dioxide was tested. The larger the color difference value, the greater the difference in color performance between the two; the smaller the color difference, the smaller the difference in color performance between the two. Impact strength: Tested according to GB / T 1843-2008 using Chengde Jinjian XJUD-5.5 electronic cantilever beam impact testing machine.

[0087] Table 2. Product performance test results obtained from Application Examples 1-8 and Comparative Examples 1-2

[0088] As shown in Table 2, when the ultra-white ultrafine barite powder prepared in Example 4 was used in the preparation of ABS plastic, and the color difference of the samples prepared by replacing it with pure titanium dioxide was compared with that of the samples prepared by adding pure titanium dioxide, the color difference of the samples was within the qualified range according to the judgment standard of the testing instrument, and was judged as qualified. Among them, the sample prepared by using 300g titanium dioxide + 100g barium sulfate had the smallest color difference. In this formula, the ultra-white ultrafine barite powder obtained in Example 4 replaced 25% of the amount of titanium dioxide. The color performance of the sample was consistent with that of the sample prepared by adding pure titanium dioxide. This is because the ultra-white ultrafine barite powder can be better dispersed in the "cavities" between the titanium dioxide particles, so as to better bring out the surface benefits of the titanium dioxide particles.

[0089] Analysis of the impact strength test results shows that adding titanium dioxide to ABS plastic reduced the impact strength by 8.6%. However, the titanium dioxide + barium sulfate formulation showed a certain degree of improvement in impact strength compared to the titanium dioxide-only formulation. In particular, the 300g titanium dioxide + 100g barium sulfate formulation had an impact strength close to that of pure ABS, and a 9.2% improvement compared to the pure titanium dioxide formulation. This is because the ultrafine barium sulfate particles are more easily dispersed in the ABS substrate. When subjected to external impact, the ultrafine particles can withstand greater force, thus improving the impact strength.

[0090] The data above shows that the ultra-white and ultra-fine barite powder prepared by this invention can partially replace titanium dioxide when applied to ABS plastic, while maintaining good color performance and impact resistance.

[0091] Application Comparative Example 3

[0092] Replace the barium sulfate in Application Example 4 with the product described in Comparative Example 1, and follow the same steps as in Application Example 4.

[0093] Application Comparative Example 4

[0094] Replace the barium sulfate in Application Example 4 with the product described in Comparative Example 2, and follow the same steps as in Application Example 4.

[0095] Application Comparative Example 5

[0096] Replace the barium sulfate in Application Example 4 with the product described in Comparative Example 3, and follow the same steps as in Application Example 4.

[0097] The color difference and impact strength tests were performed on the products obtained from comparative examples 3 to 5, and the test results are shown in Table 3.

[0098] Table 3. Product performance test results obtained from Application Example 4 and Comparative Examples 1-5

[0099] As shown in Table 3, when different types of barium sulfate are used to replace 25% titanium dioxide in ABS plastic, the impact strength is: precipitated barium sulfate (Comparative Examples 2 and 3) > ultra-white ultrafine barite powder obtained in Example 4 > Comparative Example 1. Similarly, when barium sulfate is produced by physical methods, the finer the particle size, the more particles per unit mass of powder, and the greater the force it can withstand when impacted. Precipitated barium sulfate has a larger specific surface area and a greater number of particles, resulting in higher impact strength.

[0100] From the results of color difference, the color difference value of Application Example 4 is smaller than that of Application Comparative Examples 3-4. Compared with Application Comparative Example 3, the ultra-white ultrafine barite powder particles prepared by this invention are finer and have better dispersion effect, making it easier to "open" the titanium dioxide particles in the ABS substrate, resulting in better color performance. Since Comparative Examples 2 and 3 are both precipitated barium sulfate, precipitated barium sulfate is more likely to form particle agglomeration at the application end, affecting its dispersion effect and causing its color difference to increase.

[0101] Based on the above application evaluations, the ultra-white and ultra-fine barite powder prepared by this invention can partially replace titanium dioxide in ABS plastics, maintaining its impact resistance while achieving excellent color performance.

[0102] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing ultra-white, ultrafine barite powder, characterized in that, The preparation method includes the following steps: sequentially subjecting barite coarse powder to gravity separation, dry grinding, magnetic separation, wet ball milling and air classification to obtain ultra-white ultrafine barite powder.

2. The method for preparing ultra-white ultrafine barite powder according to claim 1, characterized in that, The particle size of the barite coarse powder is 0.5~1cm; The gravity separation involves feeding barite coarse powder to a jig for gravity separation to obtain concentrate. The density of the concentrate is ≥4.2 g / cm³. 3 .

3. The method for preparing ultra-white ultrafine barite powder according to claim 1 or 2, characterized in that, The fineness D97 of the product after dry grinding is 20~30μm; The magnetic separation is carried out in a dry magnetic separator.

4. The method for preparing ultra-white ultrafine barite powder according to claim 1, characterized in that, In the wet ball milling process, the grinding media is ceramic balls, the grinding liner is ceramic brick, the grinding time is 30-80 minutes, and the grinding speed is 14-30 rpm.

5. The method for preparing ultra-white ultrafine barite powder according to claim 4, characterized in that, During the wet ball milling process, an aqueous solution containing a dispersant is added, and the amount of the aqueous solution containing the dispersant added is 80~150L / h. The dispersant is one or more of sodium polyacrylate, polyacrylamide, polyacrylic acid, and polyethylene glycol; The concentration of the dispersant in the aqueous solution is 5-12 wt%.

6. The method for preparing ultra-white ultrafine barite powder according to claim 1, characterized in that, In the air separation grading process, the classifier rotates at a speed of 2000~4000 rpm, and the number of grading wheels in the classifier is 3~6.

7. The ultra-white ultra-fine barite powder prepared by the method of preparing ultra-white ultra-fine barite powder according to any one of claims 1 to 6.

8. The ultra-white, ultrafine barite powder according to claim 7, characterized in that, The ultra-white ultrafine barite powder has a D50 of 1.2~1.5μm, a D97 of 3.5~4μm, a whiteness ≥94.5, and a barium sulfate content ≥94.5%.

9. The application of the ultra-white ultrafine barite powder according to claim 7 or 8 in partially replacing titanium dioxide in ABS plastic.

10. The application of the ultra-white ultrafine barite powder according to claim 9 in partially replacing titanium dioxide in ABS plastic, characterized in that, The amount of ultra-white ultrafine barite powder replacing titanium dioxide is 10~30wt%.

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