Process for the preparation of a matt mica powder

Abstract

The application relates to the technical field of mica powder and discloses a preparation method of matte mica powder, which comprises the following steps: S1, mica sheets are treated with a pretreatment agent, crushed, classified, and mica sheet slurry is obtained; the pretreatment agent is obtained by mixing benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 2-4:2:100; S2, the mica sheet slurry is subjected to pressure filtration dewatering and grinding to obtain ground slurry; S3, the mass fraction of mica powder in the ground slurry is adjusted, the mica powder is dispersed and sieved, and mica powder with a diameter-thickness ratio greater than 90 is obtained; and S4, the mica powder with the diameter-thickness ratio greater than 90 is rinsed, impurities are removed through precipitation, dewatered and dried, and matte mica powder is obtained. Through the technical scheme, the problem of poor matte effect of mica powder in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of mica powder technology, and more specifically, to a method for preparing matte mica powder. Background Technology

[0002] Mica powder, as a two-dimensional inorganic material, is finding new applications and developments in fields such as cosmetic substrates, pearlescent pigments, coating fillers, decorative materials, and plastic modification. Currently, mica powder processing mainly involves two processes: dry production and wet production, with the grinding method being the key technology. The grinding method influences the application value and direction of mica powder, playing a decisive role in the functionality of mica materials.

[0003] With the upgrading and iteration of industry products, matte products have gained market favor; however, the mica powder produced by existing technologies has a pearly reflective luster and an oily luster, which can no longer meet market demand; therefore, it is of great significance to develop a method for preparing matte mica powder. Summary of the Invention

[0004] This invention proposes a method for preparing matte mica powder, which solves the problem of poor matte effect of mica powder in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a method for preparing matte mica powder, comprising the following steps: S1. After treating the mica flakes with a pretreatment agent, crush and classify them to obtain mica flake slurry. The pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 2-4:2:100; S2. The mica sheet slurry is dehydrated by pressure filtration and then ground to obtain a ground slurry. S3. Adjust the mass fraction of mica powder in the ground slurry, disperse it, and sieve it to obtain mica powder with a diameter-to-thickness ratio greater than 90. S4. The mica powder with a diameter-to-thickness ratio greater than 90 is washed, precipitated to remove impurities, dehydrated and dried to obtain matte mica powder.

[0006] As a further technical solution, in step S1, the pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 3:2:100.

[0007] As a further technical solution, in step S1, the ratio of mica sheets to pretreatment agent is 1g:20-30mL.

[0008] As a further technical solution, in step S1, high-pressure hydraulic crushing is used during the crushing process, with a water pressure of 5-6 MPa.

[0009] As a further technical solution, in step S2, after pressure filtration and dehydration, the mass fraction of mica sheets is 30%-40%.

[0010] As a further technical solution, in step S3, the mass fraction of the mica powder is 6%-10%.

[0011] As a further technical solution, step S4 includes a secondary matting process. The method of the secondary matting process is as follows: the matte mica powder is mixed with a grinding aid, ground, homogenized with water, magnetically separated, washed, precipitated and dried to obtain high-quality matte mica powder. The grinding aid is composed of polyurethane, alumina and silicon nitride in a mass ratio of 1:1:1-2.

[0012] As a further technical solution, the mass ratio of the matte mica powder to the grinding aid is 25:3.

[0013] As a further technical solution, during the water homogenization treatment, the mass fraction of the matte mica powder is 10%-15%.

[0014] As a further technical solution, during the rinsing process, the mass fraction of the matte mica powder is 6%-8%.

[0015] The working principle and beneficial effects of this invention are as follows: 1. In this invention, the pretreatment of mica flakes with benzalkonium chloride and sodium pyrophosphate helps to reduce the thickness of mica powder in subsequent processes, enhances the matting effect of mica powder, and effectively eliminates the reflective properties of mica surface.

[0016] 2. In this invention, a grinding aid composed of polyurethane, alumina and silicon nitride is used to perform a secondary matte treatment on matte mica powder, which can further improve the matte effect of mica powder. Detailed Implementation

[0017] 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.

[0018] Unless otherwise specified, in the following examples and comparative examples, the mica sheets were natural mica sheets purchased from Lingshou County Huada Mineral Products Processing Plant; benzalkonium chloride was purchased from Aladdin Biochemical Technology Co., Ltd., item number A194586; sodium pyrophosphate was purchased from Aladdin Biochemical Technology Co., Ltd., item number S108847; polyurethane was purchased from Haozheng New Material Technology (Dongguan) Co., Ltd., grade ES80A11; alumina was purchased from Aladdin Biochemical Technology Co., Ltd., item number A431928; and silicon nitride was purchased from Aladdin Biochemical Technology Co., Ltd., item number S431556.

[0019] Example 1 A method for preparing matte mica powder includes the following steps: S1. After immersing 1000kg of mica flakes in 20000L of pretreatment agent for 1.5h, high-pressure hydraulic crushing is performed at a water pressure of 6MPa. After classification in a gravity classifier, mica flake slurry is obtained. The pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 2:2:100. S2. The mica flake slurry is dehydrated by pressure filtration to obtain a mica flake mass fraction of 30% after dehydration. The slurry is then ground in a stirred mill at a speed of 430 rpm to obtain the ground slurry. S3. Add water to the ground slurry so that the mass fraction of mica powder in the slurry is 6%, disperse, and sieve to obtain mica powder with an aspect ratio of 90-110. S4. Rinse the mica powder, remove impurities by sedimentation, dehydrate and dry to obtain matte mica powder.

[0020] Example 2 A method for preparing matte mica powder includes the following steps: S1. After immersing 1000 kg of mica flakes in 30000 L of pretreatment agent for 1 hour, the mica flakes are crushed by high-pressure hydraulic crushing at a water pressure of 6 MPa and then classified in a gravity classifier to obtain mica flake slurry. The pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 4:2:100. S2. The mica flake slurry is dehydrated by pressure filtration to obtain a mica flake mass fraction of 40% after dehydration. The slurry is then ground in a stirred mill at a speed of 430 rpm to obtain the ground slurry. S3. Add water to the ground slurry so that the mass fraction of mica powder in the slurry is 10%, disperse, and sieve to obtain mica powder with an aspect ratio of 90-110. S4. Rinse the mica powder, remove impurities by sedimentation, dehydrate and dry to obtain matte mica powder.

[0021] Example 3 The only difference between this embodiment and embodiment 2 is that in step S1 of this embodiment, the pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 2:2:100.

[0022] Example 4 The only difference between this embodiment and embodiment 2 is that in step S1 of this embodiment, the pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 3:2:100.

[0023] Example 5 A method for preparing matte mica powder includes the following steps: S1. After immersing 1000 kg of mica flakes in 30000 L of pretreatment agent for 1 hour, the mica flakes are crushed by high-pressure hydraulic crushing at a water pressure of 6 MPa and then classified in a gravity classifier to obtain mica flake slurry. The pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 3:2:100. S2. The mica flake slurry is dehydrated by pressure filtration to obtain a mica flake mass fraction of 40% after dehydration. The slurry is then ground in a stirred mill at a speed of 430 rpm to obtain the ground slurry. S3. Add water to the ground slurry so that the mass fraction of mica powder in the slurry is 10%, disperse, and sieve to obtain mica powder with an aspect ratio of 90-110. S4. The mica powder is washed, and after sedimentation and impurity removal, it is dehydrated and dried to obtain matte mica powder. S5. Mix matte mica powder with grinding aid and grind it using a stirred mill at a speed of 120 rpm. Dilute the ground matte mica powder with water to a mass fraction of 10%, then pump it to a homogenization tank for chemical treatment. After magnetic separation, overflow into a rinsing tank, add water to make the mass fraction of matte mica powder 6%, precipitate, and dry to obtain high-quality matte mica powder. The mass ratio of matte mica powder to grinding aid is 25:3. The grinding aid is a mixture of polyurethane, alumina, and silicon nitride in a mass ratio of 1:1:1.

[0024] Example 6 A method for preparing matte mica powder includes the following steps: S1. After immersing 1000 kg of mica flakes in 30000 L of pretreatment agent for 1 hour, the mica flakes are crushed by high-pressure hydraulic crushing at a water pressure of 6 MPa and then classified in a gravity classifier to obtain mica flake slurry. The pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 3:2:100. S2. The mica flake slurry is dehydrated by pressure filtration to obtain a mica flake mass fraction of 40% after dehydration. The slurry is then ground in a stirred mill at a speed of 430 rpm to obtain the ground slurry. S3. Add water to the ground slurry so that the mass fraction of mica powder in the slurry is 10%, disperse, and sieve to obtain mica powder with an aspect ratio of 90-110. S4. The mica powder is washed, and after sedimentation and impurity removal, it is dehydrated and dried to obtain matte mica powder. S5. Mix matte mica powder with grinding aid and grind it using a stirred mill at a speed of 120 rpm. Dilute the ground matte mica powder with water to a mass fraction of 15%, then pump it to a homogenization tank for chemical treatment. After magnetic separation, overflow into a rinsing tank, add water to make the mass fraction of matte mica powder 8%, precipitate, and dry to obtain high-quality matte mica powder. The mass ratio of matte mica powder to grinding aid is 25:3. The grinding aid is a mixture of polyurethane, alumina, and silicon nitride in a mass ratio of 1:1:2.

[0025] Example 7 A method for preparing matte mica powder includes the following steps: S1. After immersing 1000 kg of mica flakes in 30000 L of pretreatment agent for 1 hour, the mica flakes are crushed by high-pressure hydraulic crushing at a water pressure of 6 MPa and then classified in a gravity classifier to obtain mica flake slurry. The pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 3:2:100. S2. The mica flake slurry is dehydrated by pressure filtration to obtain a mica flake mass fraction of 40% after dehydration. The slurry is then ground in a stirred mill at a speed of 430 rpm to obtain the ground slurry. S3. Add water to the ground slurry so that the mass fraction of mica powder in the slurry is 10%, disperse, and sieve to obtain mica powder with an aspect ratio of 90-110. S4. The mica powder is washed, and after sedimentation and impurity removal, it is dehydrated and dried to obtain matte mica powder. S5. Grind the matte mica powder using a stirred mill at a speed of 120 rpm. Dilute the ground matte mica powder with water to a mass fraction of 10%, then pump it to a homogenization tank for chemical treatment. After magnetic separation, the powder overflows into a rinsing tank, where water is added to make the mass fraction of the matte mica powder 6%. After sedimentation and drying, high-quality matte mica powder is obtained.

[0026] Comparative Example 1 The only difference between this comparative example and Example 1 is that no pretreatment agent was added in step S1 of this comparative example.

[0027] Comparative Example 2 The only difference between this comparative example and Example 1 is that in step S1 of this comparative example, the pretreatment agent is a mixture of benzalkonium chloride and water in a mass ratio of 2:100.

[0028] Comparative Example 3 The only difference between this comparative example and Example 1 is that in step S1 of this comparative example, the pretreatment agent is a mixture of sodium pyrophosphate and water in a mass ratio of 2:100.

[0029] The mica powders prepared in Examples 1-7 and Comparative Examples 1-3 were compacted into cakes, and the gloss of the mica powders was measured using an MN60 general-purpose gloss meter (Tianjin Qili Technology Co., Ltd.). The measurement results are shown in Table 1 below.

[0030] Table 1. Gloss Measurement Results

[0031] The data in the table show that the mica powder prepared by this invention has a good matte finish, which meets market demand. A comparison of Example 1 with Comparative Examples 1-3 shows that benzalkonium chloride and sodium pyrophosphate in the pretreatment agent work synergistically to improve the matte finish of the mica powder. A comparison of Example 4 with Examples 2-3 shows that the optimal mass ratio of benzalkonium chloride, sodium pyrophosphate, and water in the pretreatment agent is 3:2:100. A comparison of Example 5 with Example 7 shows that using a grinding aid composed of polyurethane, alumina, and silicon nitride to perform a secondary matte treatment on the matte mica powder can further improve its matte finish.

[0032] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing matte mica powder, characterized in that, Includes the following steps: S1. After treating the mica flakes with a pretreatment agent, crush and classify them to obtain mica flake slurry. The pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 2-4:2:100; The ratio of mica flakes to pretreatment agent is 1g:20-30mL; S2. The mica sheet slurry is dehydrated by pressure filtration and then ground to obtain a ground slurry. S3. Adjust the mass fraction of mica powder in the ground slurry, disperse it, and sieve it to obtain mica powder with a diameter and thickness greater than 90 mm. S4. The mica powder with a diameter-to-thickness ratio greater than 90 is washed, precipitated to remove impurities, dehydrated and dried to obtain matte mica powder. Step S4 is followed by a secondary matte treatment, which is performed by mixing the matte mica powder with a grinding aid, grinding, adding water for homogenization, followed by magnetic separation, rinsing, sedimentation, and drying to obtain high-quality matte mica powder. The grinding aid is composed of polyurethane, alumina and silicon nitride in a mass ratio of 1:1:1-2.

2. The method for preparing matte mica powder according to claim 1, characterized in that, In step S1, the pretreatment agent is a mixture of benzalkonium chloride, sodium pyrophosphate and water in a mass ratio of 3:2:

100.

3. The method for preparing matte mica powder according to claim 1, characterized in that, In step S1, the crushing process is carried out using high-pressure hydraulic crushing with a water pressure of 5-6 MPa.

4. The method for preparing matte mica powder according to claim 1, characterized in that, In step S2, after pressure filtration and dehydration, the mass fraction of mica sheets is 30%-40%.

5. The method for preparing matte mica powder according to claim 1, characterized in that, In step S3, the mica powder has a mass fraction of 6%-10%.

6. The method for preparing matte mica powder according to claim 1, characterized in that, The mass ratio of the matte mica powder to the grinding aid is 25:

3.

7. The method for preparing matte mica powder according to claim 1, characterized in that, During the water homogenization treatment, the mass fraction of the matte mica powder is 10%-15%.

8. The method for preparing matte mica powder according to claim 1, characterized in that, During the rinsing process, the mass fraction of the matte mica powder is 6%-8%.

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