Production method of flaky zinc powder
Through the two-step ball milling method and the use of surface modification additives, the problem of difficulty in preparing sheet zinc powder is solved, and efficient and uniform zinc powder preparation is achieved, which improves application performance and reduces costs.
Patent Information
- Application Number
- CN202510356253.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-05-06
AI Technical Summary
In the prior art, the method of producing sheet zinc powder mainly relies on the grinding method, and there are no public reports on the technology of preparing sheet zinc powder for irregular hydraulic atomization zinc powder, resulting in complex production process and high cost.
A two-step ball milling method was used to prepare sheet zinc powder. First, the zinc powder raw material with a narrow particle size range was obtained through screening, and then high-speed and low-speed ball milling was performed with solvent, dispersant and surface modification additives to control the median particle size and surface modification of the zinc powder.
The goal of preparing sheet zinc powder with irregular hydraulic atomized zinc powder as raw material has been achieved, improving the uniformity, surface smoothness and application performance of zinc powder, reducing production costs, and expanding the application range.
Smart Images
Figure CN119927200A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of flaky metal powder production, in particular to a method for producing flaky zinc powder. Background Art
[0002] Flake zinc powder is an important functional powder material, mainly used in anti-corrosion coatings such as Dacromet coatings, chrome-free Dacromet coatings and zinc-rich coatings, which protect the steel surface. When the anti-corrosion coating prepared with flake zinc powder as the key raw material is coated, the flake metal powder is parallel to the coated object, interconnected, and covered with each other, arranged in multiple layers to form a barrier, so that the metal scales block the micropores of the film-forming object, prevent the penetration of harmful gases or liquids from the outside into the coating, protect the coating and the coated objects, and play a good physical shielding and anti-corrosion role; moreover, in addition to the shielding ability, the flake zinc powder also has a cathodic protection effect. A large amount of zinc is connected to form a conductive layer in the coating. When the coating encounters electrochemical corrosion, zinc is corroded first because it has a negative electrode potential difference than iron, thereby protecting the steel substrate; in addition, because the flake zinc powder has a bright metallic luster, it can play a good decorative role on the coating.
[0003] At present, grinding is one of the main methods for producing flaky zinc powder. This method usually uses spherical zinc powder prepared by evaporation condensation or gas atomization as raw material. The flaky zinc powder prepared after grinding has a smooth surface, regular edges, high bulk density, and high metallic gloss, which can meet the requirements of high corrosion resistant coatings. However, there is no public report on the technology of preparing flaky zinc powder by irregular hydraulic atomization of zinc powder. Summary of the invention
[0004] The purpose of the present invention is to provide a method for producing flaky zinc powder. The present invention can use irregular hydraulic atomized zinc powder as a raw material to prepare flaky zinc powder through a two-step ball milling method.
[0005] To achieve the above object, the present invention provides the following solutions:
[0006] The present invention provides a method for producing flaky zinc powder, comprising the following steps:
[0007] Screening the hydraulically atomized zinc powder to obtain screened zinc powder;
[0008] The sieved zinc powder is mixed with a solvent and a dispersant for a first ball milling, and the particle size change of the zinc powder is detected during the first ball milling process. When the median particle size D50 of the zinc powder is 18 micrometers to 22 micrometers, the first ball milling is stopped;
[0009] Adding a surface modification agent to the mixture obtained by the first ball milling to perform a second ball milling, followed by solid-liquid separation, vacuum drying, and sieving to obtain the flaky zinc powder;
[0010] The rotation speed of the first ball milling is 100 to 200 rpm; during the first ball milling process, if the ball milling speed is too low, the flaking efficiency is low, and if the ball milling speed is too high, the powder is easily excessively broken and the surface flatness of the flaking is poor.
[0011] The second ball milling has a rotation speed of 20 to 50 rpm and a ball milling time of 1 to 5 hours. During the second ball milling, the rotation speed is appropriately controlled to prevent secondary flaking and achieve surface modification additive coating on the surface of the flaky zinc powder.
[0012] In a preferred embodiment of the present invention, the water content of the hydraulically atomized zinc powder is not more than 25 wt %. Too high a water content in the hydraulically atomized zinc powder affects the solubility of the dispersant and the surface modification additive in the ball milling solvent, reduces the ball milling flaking efficiency, and affects the coating modification effect.
[0013] In a preferred embodiment of the present invention, the particle size d of the sieved zinc powder is one of d<25 microns, 25 microns≤d<75 microns, and d≥75 microns. The particle size of the zinc powder can be controlled within a certain range by sieving, which can ensure that the flaky zinc powder has good uniformity after ball milling.
[0014] In a preferred embodiment of the present invention, the mass ratio of the sieved zinc powder to the solvent and the dispersant is (30-50):(45-65):(2-5).
[0015] In a preferred embodiment of the present invention, the solvent is No. 200 solvent oil; the dispersant is at least one of polyethylene glycol, polypropylene glycol, fatty acid polyethylene glycol ester, polyacrylamide, stearic acid amide, oleic acid amide, erucic acid amide and super dispersant.
[0016] In a preferred embodiment of the present invention, the surface modification agent is at least one of a silane coupling agent, an aluminate coupling agent, a titanate coupling agent, an adhesion promoter, a metal corrosion inhibitor and a metal brightener; the added amount of the surface modification agent is 0.5% to 2.1% of the mass of the screened zinc powder.
[0017] In a preferred embodiment of the present invention, the solid-liquid separation is performed using a centrifuge or a filter press; the liquid content in the primary paste-like flaky zinc powder obtained after the solid-liquid separation is 10% to 20%.
[0018] In a preferred embodiment of the present invention, the vacuum drying temperature is 80° C. to 120° C., and the time is 3 to 10 hours; and the liquid content in the zinc powder after the vacuum drying is no more than 1%.
[0019] The vacuum drying adopts a vacuum oven or a vacuum rake dryer.
[0020] In a preferred embodiment of the present invention, the screening is performed by a vibrating screen; and the particle size of the flaky zinc powder is not greater than 45 microns.
[0021] The present invention discloses the following technical effects:
[0022] The present invention uses water-containing irregular hydraulic atomized zinc powder to prepare flaky zinc powder. First, a zinc powder raw material with a narrow particle size range is obtained by screening to ensure that the particle size uniformity of the zinc powder after flaking is consistent; then the zinc powder in a certain particle size range is subjected to two-step ball milling to prepare flaky zinc powder, wherein the first step is high-speed grinding, mainly to achieve the flaking of zinc powder, and the second step is low-speed grinding with the addition of a surface modification additive, mainly to achieve particle shaping after flaking, and at the same time improve the application compatibility, adhesion and gloss of the flaky zinc powder in anti-corrosion coatings. The use of low-priced hydraulic atomized zinc powder as a raw material to prepare flaky zinc powder can expand the application range of the zinc powder, thereby realizing the added value of low-end products, and the product can be used in anti-corrosion coatings such as Dacromet coatings, chromium-free Dacromet coatings and zinc-rich coatings to reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0024] Figure 1 The microscopic morphology of the hydraulically atomized zinc powder in Example 1;
[0025] Figure 2 This is the microscopic morphology of the flaky zinc powder prepared in Example 1. DETAILED DESCRIPTION
[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0027] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.
[0028] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.
[0029] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.
[0030] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.
[0031] The "%" described in the present invention, unless otherwise specified, refers to mass percentage.
[0032] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.
[0033] The hydraulically atomized zinc powder used in the embodiments of the present invention comes from Chifeng Zhongse Zinc Industry Co., Ltd., and the metal zinc content is ≥96%; the polyethylene glycol is specifically PEG-200; the silane coupling agent is specifically aminosilane KH550; the metal brightener is specifically kpl-885210; the polypropylene glycol is specifically PPG-200; the aluminate coupling agent is specifically PN-827; the adhesion promoter is specifically PN-700; the hyperdispersant is specifically GA-100; and the titanate coupling agent is specifically PN-105.
[0034] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0035] Example 1
[0036] The hydraulically atomized zinc powder with a water content of 15% was sieved through a vibrating sieve with a mesh size of 25 microns and 75 microns to obtain zinc powder of 25 to 75 microns. 1.5 kg of sieved zinc powder, 1.8 kg of No. 200 solvent oil, 0.08 kg of stearic acid amide and 0.04 kg of polyethylene glycol were weighed and added to the ball mill in sequence. The ball milling medium was zirconium oxide balls, the ball-to-material ratio was 10:1, the grinding speed was set to 150 rpm, and grinding began. When the median particle size D50 of the powder was 19 microns, grinding was stopped; 0.01 kg of silane coupling agent and 0.01 kg of metal brightener were added to the ball mill, and the ball mill speed was set to 25 rpm to start the second grinding ( The ball milling medium is zirconia balls, the ball-to-material ratio is 10:1, and the grinding time is 4 hours; the sieve slurry obtained after the second grinding is sent to a filter press for solid-liquid separation to obtain a primary paste-like flaky zinc powder with a grinding solvent content of 13%; the paste-like flaky zinc powder is sent to a vacuum drying oven, the drying temperature is 80°C, the drying time is 10 hours, and a dry flaky zinc powder with a liquid content of 0.2% is obtained; the dried flaky zinc powder is sieved through a vibrating screen with a mesh number of 45 microns to obtain a flaky zinc powder with a particle size not greater than 45 microns.
[0037] Example 2
[0038] The hydraulically atomized zinc powder with a water content of 20% was sieved through a vibrating sieve with a mesh size of 25 microns to obtain zinc powder less than 25 microns. 1.2 kg of sieved zinc powder, 2.0 kg of No. 200 solvent oil, 0.06 kg of fatty acid polyethylene glycol ester and 0.05 kg of polypropylene glycol were weighed and added to the ball mill in sequence. The ball milling medium was zirconium oxide balls, the ball-to-material ratio was 10:1, the grinding speed was set to 130 rpm, and grinding began. When the median particle size D50 of the powder was 20 microns, grinding was stopped; 0.01 kg of aluminate coupling agent and 0.015 kg of adhesion promoter were added to the ball mill, and the ball mill speed was set to 30 rpm to start the second Grinding (ball milling medium is zirconia ball, ball-to-material ratio is 10:1), the grinding time is 3 hours; the sieve slurry obtained after the second grinding is sent to a filter press for solid-liquid separation to obtain a primary paste-like flaky zinc powder with a grinding solvent content of 12%; the paste-like flaky zinc powder is sent to a vacuum drying oven, the drying temperature is 100°C, the drying time is 6 hours, and a dry flaky zinc powder with a liquid content of 0.5% is obtained; the dried flaky zinc powder is sieved through a vibrating screen with a mesh size of 45 microns to obtain a flaky zinc powder with a particle size not greater than 45 microns.
[0039] Example 3
[0040] The hydraulically atomized zinc powder with a water content of 25% was sieved through a vibrating sieve with a mesh size of 75 microns to obtain zinc powder of not less than 75 microns. 1.8 kg of sieved zinc powder, 2.2 kg of No. 200 solvent oil, 0.03 kg of polyethylene glycol, 0.04 kg of mesoamide and 0.03 kg of superdispersant were weighed and added to the ball mill in sequence. The ball milling medium was zirconium oxide balls with a ball-to-material ratio of 10:1. The grinding speed was set to 200 rpm and grinding was started. When the median particle size D50 of the powder was 21 microns, grinding was stopped. 0.008 kg of titanate coupling agent, 0.005 kg of adhesion promoter and 0.007 kg of metal brightener were added to the ball mill, and the ball mill speed was set to 5 0 rpm, start the second grinding (ball milling medium is zirconia ball, ball-to-material ratio is 10:1), the grinding time is 2 hours; the sieve slurry obtained after the second grinding is sent to the filter press for solid-liquid separation to obtain the primary paste-like flaky zinc powder with a grinding solvent content of 15%; the paste-like flaky zinc powder is sent to a vacuum drying oven, the drying temperature is 90°C, the drying time is 7 hours, and the dry flaky zinc powder with a liquid content of 0.7% is obtained; the dried flaky zinc powder is sieved through a vibrating screen with a mesh number of 45 microns to obtain flaky zinc powder with a particle size of not more than 45 microns.
[0041] Figure 1 The microscopic morphology of the hydraulically atomized zinc powder in Example 1;
[0042] Figure 2 The microscopic morphology of the flaky zinc powder prepared in Example 1. Figure 2 It can be seen that the prepared flaky zinc powder has a high flake rate, a smooth surface, relatively regular edges and good particle uniformity.
[0043] The application effects of the flaky zinc powder prepared in Examples 1 to 3 were verified as follows:
[0044] The flaky zinc powder prepared in Example 1 was used to carry out Dacromet coating (composed of flaky zinc powder, flaky aluminum powder, chromic acid, deionized water, thickener, leveling agent, etc.) and coating performance assessment test. The viscosity of the coating was 97s and the specific gravity was 1.295g / cm 3 , which can meet the performance requirements of Dacromet coatings, and at the same time prepare Dacromet anti-corrosion parts, with a salt spray test of 1152h, and the corrosion resistance reaches the highest level 4 standard of Dacromet coating (GB / T 18684 zinc-chromium coating technical requirements).
[0045] The flaky zinc powder prepared in Example 2 and Example 3 was subjected to Dacromet coating and coating performance assessment test. The results were similar to those in Example 1 and could also meet the performance requirements of Dacromet coating. The coating prepared using the flaky zinc powder in Example 2 had a viscosity of 96s and a specific gravity of 1.292 g / cm 3 The coating prepared by using the flaky zinc powder in Example 3 has a viscosity of 92s and a specific gravity of 1.290g / cm3 The prepared Dacromet anti-corrosion parts have a salt spray test of 1032h in Example 2 and a salt spray test of 1080h in Example 3, and the corrosion resistance reaches the highest level 4 standard of Dacromet coating.
[0046] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.
Claims
1. A method for producing flaky zinc powder, characterized in that: The following steps are involved: Screening the hydraulically atomized zinc powder to obtain screened zinc powder; The sieved zinc powder is mixed with a solvent and a dispersant for a first ball milling, and when the median particle size D50 of the zinc powder is 18 microns to 22 microns, the first ball milling is stopped; Adding a surface modification agent to the mixture obtained by the first ball milling to perform a second ball milling, followed by solid-liquid separation, vacuum drying, and sieving to obtain the flaky zinc powder; The rotation speed of the first ball milling is 100 rpm to 200 rpm; The rotation speed of the second ball milling is 20 rpm to 50 rpm, and the ball milling time is 1 to 5 hours.
2. The method for producing flaky zinc powder according to claim 1, characterized in that: The water content of the hydraulically atomized zinc powder is not more than 25 wt %.
3. The method for producing flaky zinc powder according to claim 1, characterized in that: The particle size d of the sieved zinc powder is one of d<25 microns, 25 microns≤d<75 microns, and d≥75 microns.
4. The method for producing flaky zinc powder according to claim 1, characterized in that: The mass ratio of the sieved zinc powder to the solvent and the dispersant is (30-50):(45-65):(2-5).
5. The method for producing flaky zinc powder according to claim 1, characterized in that: The solvent is No. 200 solvent oil; the dispersant is at least one of polyethylene glycol, polypropylene glycol, fatty acid polyethylene glycol ester, polyacrylamide, stearic acid amide, oleic acid amide, erucic acid amide and super dispersant.
6. The method for producing flaky zinc powder according to claim 1, characterized in that: The surface modification agent is at least one of a silane coupling agent, an aluminate coupling agent, a titanate coupling agent, an adhesion promoter, a metal corrosion inhibitor and a metal brightener; the added amount of the surface modification agent is 0.5% to 2.1% of the mass of the screened zinc powder.
7. The method for producing flaky zinc powder according to claim 1, characterized in that: The liquid content of the primary paste-like flaky zinc powder obtained after solid-liquid separation is 10% to 20%.
8. The method for producing flaky zinc powder according to claim 1, characterized in that: The vacuum drying temperature is 80° C. to 120° C., and the time is 3 to 10 hours; and the liquid content in the zinc powder after the vacuum drying is no more than 1%.
9. The method for producing flaky zinc powder according to claim 1, characterized in that: The particle size of the flaky zinc powder is no greater than 45 microns.