CN117361924B

CN117361924B - A method for preparing dolomite powder coated with nano-oxide

Info

Publication number: CN117361924B
Application number: CN202311216842.6A
Authority: CN
Inventors: 李良; 张洪运
Original assignee: Shanxi Oubeim Nanotechnology Co ltd
Current assignee: Shanxi Oubeim Nanotechnology Co ltd
Priority date: 2023-09-20
Filing date: 2023-09-20
Publication date: 2025-01-28
Anticipated expiration: 2043-09-20
Also published as: CN117361924A

Abstract

The invention discloses a preparation method of dolomite powder coated by nano oxide, which belongs to the technical field of nano oxide modification treatment and comprises the following raw materials, by weight, 80% -85% of dolomite powder, 10% -18% of nano oxide, 1% -5% of coupling agent and 0.5% -1.5% of dispersing agent. The product produced by the dolomite powder coated by the nano oxide has compact surface layer, higher content of the nano oxide, no mould growth condition on the surface layer of the product, and more effective function of mould proofing and antibiosis. The preparation method of the dolomite powder coated by the nano oxide provided by the invention does not need a high-temperature environment, the production condition is easy to realize, the agglomeration of the nano oxide is avoided, the coupling agent is not carbonized due to high temperature, and the performance of the coated particles is ensured.

Description

Preparation method of dolomite powder coated by nano oxide

Technical Field

The invention relates to a preparation method of dolomite powder coated by nano oxide, belonging to the technical field of nano oxide modification treatment.

Background

The nano powder has special properties which are obviously different from those of bulk materials due to the extremely small size, for example, part of nano metal oxide has long-acting sterilization and bacteriostasis effects, and after being added into carrier materials such as marble, plastics, plates, paint and the like, the carrier materials can have mildew-proof and sterilization functions, and the performance of the carrier materials is improved. On the one hand, the properties of the nano powder strongly depend on the size, morphology and microstructure of the nano particles, and on the other hand, the nano particles have extremely large specific surface area and higher surface energy, and particle agglomeration easily occurs in the application process, so that the physical properties of the nano particles are lost. Therefore, the dispersibility of the nano metal oxide in the carrier material greatly influences the use effect thereof. In order to ensure the mildew-proof and bactericidal effects of the carrier material, the addition amount of the nano metal oxide is generally required to be increased, resulting in increased production cost. At present, the method for improving the dispersibility of the nano powder mainly uses the technologies of surface modification such as dispersing agents, surfactants and the like, and has the defects of large dosage of the modifying agents, troublesome treatment and great environmental pollution. The invention aims to provide a novel method for solving the problem of dispersibility of nano metal oxides.

The foregoing is not necessarily a prior art, and falls within the technical scope of the inventors.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a preparation method of dolomite powder coated by nano oxide, which improves the dispersibility of the nano oxide, has high hardness of dolomite particles, has no microcrack inside, reduces the defects of coated particles and improves the stability of the coated particles.

The invention realizes the aim by adopting the following technical scheme:

The preparation method of the dolomite powder coated by the nano oxide comprises the following raw materials, by weight, 80% -85% of dolomite powder, 10% -18% of nano oxide, 1% -5% of coupling agent and 0.5% -1.5% of dispersing agent;

The nano oxide is selected from any one or more of copper oxide, zinc oxide, magnesium oxide, aluminum oxide, titanium oxide and silver oxide, and the sterilization variety can be widened by compounding different nano oxides.

The coupling agent consists of a component A and a component B, wherein the weight ratio of the component A to the component B is 1:1-1:3, the component A is selected from any one or two of stearic acid and malic acid, the component B is selected from any one or two of a silane coupling agent and an aluminate coupling agent, and preferably, R groups in the silane coupling agent Y-R-SiX3 are short-chain alkane.

The dispersing agent is selected from one or two of acacia or sodium alkyl benzene sulfonate.

Optionally, the whiteness of the dolomite powder for blue light is 60-80.

The coupling agents are used after the purchased stock solution is diluted by 10-20 times after adding water, and the dispersing agents are dissolved and used after adding water with the weight of 1:15-1:20 times of the purchased powder.

The dolomite powder is alkaline, and the component A forming the coupling agent has acid bias, so that the component A can form micro pits on the surfaces of dolomite particles for embedding nano oxides by acid etching, the component B forming the coupling agent can further activate active sites on the surfaces of the dolomite particles, and the component A and the component B are matched with each other to improve the bonding strength of the nano oxides and the dolomite particles.

In a preferred embodiment of the present invention, the dolomite powder has a particle shape similar to a sphere, an olive or a column, has a large surface area and is compounded with the nano oxide, and the formed dolomite powder coated with the nano oxide has high dispersibility.

In a preferred embodiment of the invention, the dolomite powder has a particle size of 800-1200 meshes and the nano oxide has a particle size of 1-100 nm.

In the preferred embodiment of the invention, dolomite powder is taken from mountain and west spring Yu County, and the dolomite powder contains 5-10% of silicon dioxide, 25-32% of calcium oxide, 15-21% of magnesium oxide, less than 3% of aluminum oxide, less than 1% of ferric oxide and 5-8% of acid insoluble substances. The hardness of the silicon dioxide is high, the proper proportion of the silicon dioxide in the dolomite powder ensures the hardness of the dolomite powder, and the formed dolomite powder coated by the nano oxide has high weather resistance.

The preparation method of the dolomite powder coated by the nano oxide provided by the invention comprises the following steps:

(1) Grinding dolomite powder by a vertical mill, and then winnowing to obtain ultrafine dolomite powder with the particle size of 800-1200 meshes;

(2) Mixing dolomite powder, part of dispersing agent and coupling agent A with water, and then dispersing uniformly at high speed to prepare dolomite powder suspension with the solid content of 20-30wt%;

(3) Adding water into the nano oxide and the rest of dispersing agent, mixing, and dispersing uniformly at a high speed to prepare nano oxide suspension with the solid content of 20-30wt%;

(4) Adding water into the dolomite powder suspension, the nano oxide suspension and the coupling agent B, mixing uniformly at a low speed to prepare a mixed suspension, wherein the pH value of the mixed suspension is 6.5-7.5, preferably 6.5-7.0;

(5) Drying the mixed suspension obtained in the step (4) at a temperature lower than 35 ℃ to prepare the dolomite powder coated by the nano oxide.

Wherein the dosage of the dispersing agent in the step (2) is 80% -90% of the total weight of the dispersing agent.

In the steps (4) and (5), dolomite powder and nano oxide are fully dispersed through a dispersing agent, and the dolomite particles and the nano oxide particles are rubbed with each other in the dispersing process, so that the particle type is improved, the particle type tends to be spherical, a new interface is excited and activated, the surface activity of the dolomite particles and the nano oxide particles is improved, and the coating and the compounding of the dolomite particles and the nano oxide particles are facilitated.

In a preferred embodiment of the present invention, in step (1), the 800 mesh sieve opening rate of dolomite powder during air separation is 100%, the 950 mesh sieve opening rate is 75% ± 5%, the 1100 mesh sieve opening rate is 40% ± 5%, and the 1200 mesh sieve opening rate is less than 5%. The particle size of dolomite powder can fully fill the gaps among particles through the grading distribution, so that the void ratio is reduced. The product surface layer filled and produced by the dolomite powder coated by the nano oxide provided by the invention is more compact, and the content of the nano oxide is higher, so that the product surface layer does not have the condition of mould growth, and the mould proof and antibacterial effects are more effectively exerted.

In the preferred embodiment of the invention, in the step (2), the dispersion speed is 15-20 ten thousand revolutions per minute, the dispersion time is 30-60 min, and the dispersion temperature is not higher than 30 ℃.

In the preferred embodiment of the invention, in the step (3), the dispersion speed is 8-12 ten thousand revolutions per minute, the dispersion time is 30-60 min, and the dispersion temperature is not higher than 30 ℃.

In the preferred embodiment of the invention, in the step (4), the mixing method of the dolomite powder suspension, the nano oxide suspension and the coupling agent comprises the steps of slowly pouring the coupling agent into the dolomite powder suspension, stirring for 5min at the rotating speed of 500-800 r/min, slowly pouring the nano oxide suspension, and stirring for 30min at the rotating speed of 1000-1500 r/min.

In the preferred embodiment of the invention, when the dolomite powder coated by the nano oxide is used as a filler for preparing artificial marble, plastic profiles and wood composite boards, the drying mode in the step (5) is that the mixed suspension is air-dried at the temperature of less than 35 ℃ after water washing and suction filtration or centrifugation, water washing and re-centrifugation.

In a preferred embodiment of the invention, when the dolomite powder coated by the nano oxide is used as a filler to prepare putty powder, pointing agent and plastering mortar, the drying mode in the step (5) is that the mixed suspension is atomized and dried at the temperature of lower than 35 ℃.

The beneficial effects of the application include, but are not limited to:

According to the preparation method of dolomite powder coated by nano oxides, nano oxide particles are uniformly coated on a micron-sized dolomite particle substrate, nano oxide aggregation is avoided, the dispersibility of the nano oxides is improved, the nano oxides fully exert mildew-proof antibacterial activity, the use amount of the nano oxides is reduced, the cost is reduced, the dolomite particles are high in hardness and have no fine cracks inside, a solid core of a coating material is formed, the defects of the coating particles are reduced, the stability of the coating particles is improved, and after the surfaces of the dolomite particles are coated with the nano oxides, edges and corners of the surfaces of the dolomite particles are further passivated, the fluidity of the coating particles is increased, and the coating material is beneficial to dispersion.

The product produced by the dolomite powder coated by the nano oxide has compact surface layer, higher content of the nano oxide, no mould growth condition on the surface layer of the product, and more effective function of mould proofing and antibiosis.

The preparation method of the dolomite powder coated by the nano oxide provided by the invention does not need a high-temperature environment, the production condition is easy to realize, the agglomeration of the nano oxide is avoided, the coupling agent is not carbonized due to high temperature, and the performance of the coated particles is ensured.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:

FIG. 1 is a graph of a coating model of nano-oxide particles on the surface of dolomite powder particles;

FIG. 2 is an SEM image of nano-oxide particles before and after coating the surfaces of dolomite powder particles;

FIG. 3 shows the mildew-proof test results of putty block sample 1;

FIG. 4 shows the mildew proof test results of putty block sample 2;

FIG. 5 shows the mildew-proof test results of the putty block sample 3.

Detailed Description

The present invention will be described in further detail in the following. It should be noted, however, that the following detailed description presents specific examples of the invention by way of illustration only, and the scope of the invention is not limited thereto. The scope of the invention is limited only by the claims. It will be obvious to those skilled in the art that various other modifications and substitutions can be made to the described embodiments of the invention within the scope of the invention as defined by the appended claims, and the same technical effects can still be achieved, achieving the final technical purpose of the invention.

In the embodiment, dolomite powder is taken from mountain and west spring Yu County, the whiteness of blue light is 60-80, and the proportion of the components is 5-10% of silicon dioxide, 25-32% of calcium oxide, 15-21% of magnesium oxide, less than 3% of aluminum oxide, less than 1% of ferric oxide and 5-8% of acid insoluble matters;

The chemical formula of the silane coupling agent is RSiX3, and in the silane coupling agent adopted in the embodiment of the application, R is short-chain alkane and X is halogen.

In the following examples, the weight of each coupling agent is the weight of the purchased stock solution, the stock solution is diluted by 10-20 times after adding water, the weight of each dispersing agent is the weight of the purchased powder, and the powder is dissolved after adding water with the weight of 1:15-1:20 times.

The particle size of the nano oxide is 1-100 nm.

Unless otherwise indicated, the starting materials in this specification are commercially available.

Example 1:

in the embodiment, the dolomite powder coated by the nano oxide is prepared from the following raw materials in parts by weight:

The preparation method of dolomite powder coated by nano oxide provided by the embodiment specifically comprises the following steps:

(1) Grinding dolomite powder by a vertical mill, and then winnowing to obtain ultrafine dolomite powder with the particle size of 800-1200 meshes, wherein the passing rate of 800 meshes of the dolomite powder is 100%, the passing rate of 950 meshes is 75% +/-5%, the passing rate of 1100 meshes is 40% +/-5% and the passing rate of 1200 meshes is less than 5% during winnowing;

(2) Mixing dolomite powder, 86% of dispersing agent and coupling agent A with water, and then dispersing at high speed for 50min at a rotating speed of 18 ten thousand rpm, wherein the dispersing temperature is not higher than 30 ℃, so as to prepare dolomite powder suspension with the solid content of 20 wt%;

(3) Adding water into the nano oxide and the rest of dispersing agent, mixing, and then dispersing at a high speed for 45min at a rotating speed of 10 ten thousand rpm, wherein the dispersing temperature is not higher than 30 ℃, so as to prepare nano oxide suspension with 25% of solid content;

(4) Slowly pouring a coupling agent B diluted by adding water into the dolomite powder suspension, stirring for 5min at the rotation speed of 700 rpm, slowly pouring a nano oxide suspension, and stirring for 30min at the rotation speed of 1300 rpm to prepare a mixed suspension;

(5) And (3) carrying out water washing and suction filtration or centrifugation, water washing and re-centrifugation on the mixed suspension obtained in the step (4), and then carrying out air drying at a temperature lower than 35 ℃ to prepare the dolomite powder coated by the nano oxide.

The nano-oxide coated dolomite powder prepared in example 1 has high purity, but a small amount of particles have slight agglomeration phenomenon, and is generally used as a filler for preparing artificial marble, plastic profiles and wood composite boards.

Example 2:

The dolomite powder coated by the nano oxide in the embodiment is prepared from the following raw materials in parts by weight:

This example differs from the preparation in example 1 in that:

the drying in step (5) is carried out by atomizing and drying the mixed suspension at a temperature of less than 35 ℃.

The dolomite powder coated by the nano oxide prepared in the example 1 contains a small amount of dispersing agent and coupling agent which do not participate in the reaction, has relatively low purity, and is generally used as a filler for preparing putty powder, pointing agent and plastering mortar.

Example 3:

the embodiment is different from the embodiment 1 in that the dolomite powder coated by the nano oxide in the embodiment is prepared from the following raw materials in weight:

Fig. 1 shows a coating model diagram of nano oxide particles on the surfaces of dolomite powder particles, and component a of the coupling agent forms micro pits on the surfaces of the dolomite particles for nano oxide embedding by acid etching, so that the bonding strength of the nano oxide and the dolomite particles is improved.

As shown in an SEM (scanning electron microscope) graph in fig. 2, in the invention, dolomite particles tend to be spheres after being dispersed at high speed, and after the surfaces of the dolomite particles are coated with nano oxide particles, the surface morphology of the dolomite particles is obviously changed, and the coating rate of the nano oxide is high, so that the nano oxide can be uniformly dispersed as a filler, and the performances of mildew resistance, sterilization and the like are better exerted.

The dolomite powder coated by the nano oxide is added into the putty powder for plastering the wall according to the proportion of 3 per mill to 3 percent, so that the propagation of mold can be effectively inhibited.

In order to verify the use effect of the dolomite powder coated by the nano oxide provided by the application of the invention, the application of the invention carries out the following mildew-proof test on samples 1 to 3.

Sample 1, putty powder without any mildew inhibitor;

sample 2, a mould proof putty powder sold in the market;

sample 3. Dolomite powder coated with nano oxide provided by the present application was added to sample 1 in a proportion of 1%.

According to GB/T1741-2020 mould resistance testing method, preparing three groups of samples 1-3 according to the same method, namely putty block samples 1-3, wherein each group of samples comprises three putty blocks, placing the three putty blocks in nutrient salt agar culture medium, spraying 8 moulds, placing the three groups of samples in a mould incubator with the temperature of 28 ℃ and the humidity of not lower than 85%, and culturing for 28 days, wherein the detection result is as follows:

the surface of the putty block sample 1 (figure 3) has obvious severe mold pollution, and the pollution level reaches level 4.

The putty block sample 2 (FIG. 4) had significant mold contamination with two reaching grade 4 mold contamination and one reaching grade 3 mold contamination.

The putty block sample 3 (FIG. 5) samples were free of mold contamination.

Experiments prove that the putty block sample 3 can effectively resist the corrosion of external microorganisms and germs, can be widely applied to interior decoration, especially decoration in a children room, and can effectively inhibit the propagation of wall mould in a humid environment.

The above embodiments are not to be taken as limiting the scope of the invention, and any alternatives or modifications to the embodiments of the invention will be apparent to those skilled in the art and fall within the scope of the invention.

The present invention is not described in detail in the present application, and is well known to those skilled in the art.

Claims

1. The preparation method of the dolomite powder coated by the nano oxide is characterized by comprising the following raw materials, by weight, 80% -85% of the dolomite powder, 10% -18% of the nano oxide, 1% -5% of a coupling agent and 0.5% -1.5% of a dispersing agent;

wherein the nano oxide is selected from any one or more of copper oxide, zinc oxide, magnesium oxide, aluminum oxide, titanium oxide and silver oxide;

The coupling agent consists of a component A and a component B, wherein the weight ratio of the component A to the component B is 1:1-1:3, the component A is selected from any one or two of stearic acid and malic acid, and the component B is selected from any one or two of a silane coupling agent and an aluminate coupling agent;

the dispersing agent is selected from one or two of acacia or sodium alkyl benzene sulfonate;

the dolomite powder comprises 5-10% of silicon dioxide, 25-32% of calcium oxide, 15-21% of magnesium oxide, less than 3% of aluminum oxide, less than 1% of ferric oxide and 5-8% of acid insoluble matters;

The preparation method of the dolomite powder coated by the nano oxide comprises the following steps:

(2) Mixing dolomite powder, part of dispersing agent and component A with water, and then dispersing uniformly at high speed to prepare dolomite powder suspension with the solid content of 20-30wt%;

(4) Adding water into the dolomite powder suspension, the nano oxide suspension and the component B, mixing uniformly at a low speed to prepare a mixed suspension, wherein the pH value of the mixed suspension is 6.5-7.5;

2. The method of preparing nano-oxide coated dolomite powder according to claim 1, wherein the blue light whiteness of the dolomite powder is 60-80.

3. The method for preparing dolomite powder coated with nano oxide according to claim 1, wherein the dolomite powder has a particle shape of approximately spherical, olive or columnar, the dolomite powder has a particle size of 800-1200 meshes, and the nano oxide has a particle size of 1-100 nm.

4. The method of preparing nano-oxide coated dolomite powder according to claim 1, wherein the dolomite powder is taken from shanxi yangquan Yu County.

5. The method of claim 1, wherein in step (1), the dolomite powder has a 800 mesh opening passing rate of 100%, a 950 mesh opening passing rate of 75% ± 5%, a 1100 mesh opening passing rate of 40% ± 5% and a 1200 mesh opening passing rate of less than 5%.

6. The method of claim 1, wherein in the step (2), the dispersion speed is 15 to 20 ten thousand rpm, the dispersion time is 30 to 60min, and the dispersion temperature is not higher than 30 ℃.

7. The method for preparing dolomite powder coated with nano oxide according to claim 1, wherein in the step (3), the dispersion speed is 8-12 ten thousand rpm, the dispersion time is 30-60 min, and the dispersion temperature is not higher than 30 ℃.

8. The method for preparing dolomite powder coated by nano oxide according to claim 1, wherein in the step (4), the dolomite powder suspension, the nano oxide suspension and the component B are mixed by slowly pouring the component B into the dolomite powder suspension, stirring for 5min at a rotation speed of 500-800 rpm, slowly pouring the nano oxide suspension, and stirring for 30min at a rotation speed of 1000-1500 rpm.

9. The method for preparing dolomite powder coated by nano oxide according to claim 1, wherein when the dolomite powder coated by nano oxide is used as filler for preparing artificial marble, plastic profile and wooden composite board, the drying mode in step (5) is that the mixed suspension is air-dried under the temperature lower than 35 ℃ after water washing and suction filtration or centrifugation, water washing and re-centrifugation;

When the dolomite powder coated by the nano oxide is used as a filler to prepare putty powder, pointing agent and plastering mortar, the drying mode in the step (5) is that the mixed suspension is atomized and dried at the temperature of lower than 35 ℃.