阅读说明：本技术 一种高阻燃性氢氧化铝微粉的制备方法 (Preparation method of high-flame-retardancy aluminum hydroxide micro powder ) 是由 郝亚明 于 2021-01-22 设计创作，主要内容包括：本发明公开了一种高阻燃性氢氧化铝微粉的制备方法,包括以下步骤：S101：选取足量的铝粉,使用过滤筛对铝粉进行过滤筛选；S106：将冲洗后的氢氧化铝沉淀物加入到恒温干燥箱内,在140-150℃条件下,通过恒温干燥箱干燥处理15-20分钟,得到干燥后的氢氧化铝；本发明先通过稀硫酸和铝粉制成硫酸铝,然后通过氢氧化钠溶液和铝粉制成偏铝酸钠结合两个水,接着通过硫酸铝和偏铝酸钠结合两个水在纯净水中反应得到氢氧化铝沉淀物和硫酸钠溶液,接着依次进行过滤、冲洗、干燥、研磨和筛分,得到粒径为0.074-0.4mm的氢氧化铝粉末,该制备方法简单、高效；该制备方法以铝粉、氢氧化钠和稀硫酸为原料,原料易得,成本低。(The invention discloses a preparation method of high-flame-retardancy aluminum hydroxide micro powder, which comprises the following steps: s101: selecting sufficient aluminum powder, and filtering and screening the aluminum powder by using a filter screen; s106: adding the washed aluminum hydroxide precipitate into a constant-temperature drying box, and drying for 15-20 minutes by the constant-temperature drying box under the condition of 140-150 ℃ to obtain dried aluminum hydroxide; the preparation method comprises the steps of preparing aluminum sulfate from dilute sulfuric acid and aluminum powder, preparing sodium metaaluminate and combining two water by using a sodium hydroxide solution and the aluminum powder, reacting the aluminum sulfate and the sodium metaaluminate and combining the two water in purified water to obtain an aluminum hydroxide precipitate and a sodium sulfate solution, and sequentially filtering, washing, drying, grinding and screening to obtain the aluminum hydroxide powder with the particle size of 0.074-0.4mm, wherein the preparation method is simple and efficient; the preparation method takes aluminum powder, sodium hydroxide and dilute sulfuric acid as raw materials, and the raw materials are easy to obtain and low in cost.)

1. A preparation method of high-flame-retardancy aluminum hydroxide micropowder is characterized by comprising the following steps:

s101: selecting sufficient aluminum powder, filtering and screening the aluminum powder by using a filter screen, weighing 20g of the filtered aluminum powder, and equally dividing 20g of the aluminum powder into two parts of aluminum powder A and aluminum powder B;

s102: adding a dilute sulfuric acid solution into a beaker a, then sequentially adding aluminum powder A into the beaker a, continuously stirring, and stirring for 10-15 minutes until the aluminum powder A completely reacts with the dilute sulfuric acid solution to obtain aluminum sulfate;

s103: sequentially adding purified water and sodium hydroxide into a beaker B, stirring for 3-5 minutes until the sodium hydroxide is completely dissolved in the purified water to obtain a sodium hydroxide solution, then adding aluminum powder B into the beaker B, continuously stirring for 10-15 minutes until the aluminum powder B completely reacts with the sodium hydroxide solution to obtain two water combined with sodium metaaluminate;

s104: adding purified water into a beaker c, sequentially adding the aluminum sulfate obtained in the step S102 and the sodium metaaluminate obtained in the step S103 into the beaker c in combination with the two water, and stirring for 15-20 minutes until the aluminum sulfate and the sodium metaaluminate are completely reacted in the purified water to obtain an aluminum hydroxide precipitate and a sodium sulfate solution;

s105: filtering out the aluminum hydroxide precipitate by using filter paper, then placing the filtered aluminum hydroxide precipitate on the filter paper, and washing by using purified water;

s106: adding the washed aluminum hydroxide precipitate into a constant-temperature drying oven, drying for 15-20 minutes in the constant-temperature drying oven at the temperature of 140-150 ℃ to obtain dried aluminum hydroxide, adding the dried aluminum hydroxide into a double-sided grinder, grinding the aluminum hydroxide by the double-sided grinder, and screening by a vibrating screen to obtain aluminum hydroxide powder with the particle size of 0.074-0.4 mm.

2. The method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 1, which is characterized by comprising the following steps: in step S101, a 100-mesh stainless steel filter screen is used as the filter screen.

3. The method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 2, wherein the method comprises the following steps: in step S102, the reaction formula of the aluminum powder a and the dilute sulfuric acid solution is:

2Al+3H₂SO₄(rare) ═ Al₂(SO₄)₃+3H₂↑。

4. The method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 3, wherein the method comprises the following steps: in step S102, the weight of the aluminum powder a is 10g, the concentration of the dilute sulfuric acid solution is 10% g/ml, the volume of the dilute sulfuric acid solution is 150ml, and the dilute sulfuric acid solution contains 15g of sulfuric acid.

5. The method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 4, wherein the method comprises the following steps: in step S103, the reaction formula of the aluminum powder B and the sodium hydroxide solution is:

2Al+2NaOH+6H₂0＝2Na[Al(OH)₄]+3H₂↑。

6. the method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 5, wherein the method comprises the following steps: in step S103, the weight of the aluminum powder B is 10g, the weight of the sodium hydroxide is 10g, and the weight of the purified water is 30 g.

7. The method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 6, wherein the method comprises the following steps: in step S104, the reaction formula of the aluminum sulfate and sodium metaaluminate combined with two water in purified water is:

Al₂(SO₄)₃+6Na[Al(OH)₄]+12H₂O＝8Al(OH)₃↓+3Na₂(SO₄)。

8. the method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 7, wherein the method comprises the following steps: in step S104, the weight ratio of the aluminum sulfate, sodium metaaluminate, two water and pure water is: 1:6:12.

9. The method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 8, wherein the method comprises the following steps: in step S105, the rinsing speed of the purified water is 0.2ml/min, and the rinsing time of the purified water is 20-25 min.

10. The method for preparing the aluminum hydroxide micropowder with high flame retardancy according to claim 9, wherein the method comprises the following steps: in step S106, an ultrasonic vibration sieve with a specification of Φ 2200 × 7500 is used as the vibration sieve.

Technical Field

The invention relates to the technical field of aluminum hydroxide, in particular to a preparation method of high-flame-retardancy aluminum hydroxide micro powder.

Background

Aluminum hydroxide is the most used and widely used inorganic flame retardant additive; the aluminum hydroxide serving as a flame retardant can not only resist flame, but also prevent smoke generation, does not produce dripping and toxic gas, so that the aluminum hydroxide is widely applied and the use amount is increased year by year; the application range is as follows: thermosetting plastics, thermoplastic plastics, synthetic rubber, paint, building materials and other industries; meanwhile, the aluminum hydroxide is also a basic raw material of aluminum fluoride required by the electrolytic aluminum industry, and the aluminum hydroxide is widely applied in the industry.

Aluminum hydroxide as a weight component of the flame retardant, the flame retarding effect of aluminum hydroxide being based on the thermal elimination of chemically bound water in the case of a flame in the temperature range from 200 ℃ to 400 ℃; this endothermic decomposition of aluminium hydroxide consumes energy, whereby the surface of the plastic is cooled; in addition, the released water vapor dilutes the organic degradation products of the flammable polymer; alumina remaining as a residue has a high specific surface area and absorbs polycyclic aromatic compounds formed in the combustion of the polymer; thus, these compounds are excluded from the combustion process, and since the polycyclic aromatic hydrocarbon compounds are black smoke components derived from the flame, aluminum hydroxide also contributes to a reduction in the smoke density in the case of a flame, the use of which thereby makes it possible to produce halogen-free, flame-resistant polymers without the need to use halogen-containing flame retardants.

However, the existing preparation method of the aluminum hydroxide has the following defects:

the aluminum hydroxide prepared by the prior art has larger particle size and lower crystallinity, and the crystallized aluminum hydroxide precipitate contains impurities, so that the purity of the aluminum hydroxide is reduced, the integral quality of the aluminum hydroxide is influenced, and the production cost is increased.

Disclosure of Invention

The invention aims to provide a preparation method of high-flame-retardancy aluminum hydroxide micropowder, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of high-flame-retardancy aluminum hydroxide micropowder comprises the following steps:

s101: selecting sufficient aluminum powder, filtering and screening the aluminum powder by using a filter screen, weighing 20g of the filtered aluminum powder, and equally dividing 20g of the aluminum powder into two parts of aluminum powder A and aluminum powder B;

s102: adding a dilute sulfuric acid solution into a beaker a, then sequentially adding aluminum powder A into the beaker a, continuously stirring, and stirring for 10-15 minutes until the aluminum powder A completely reacts with the dilute sulfuric acid solution to obtain aluminum sulfate;

s103: sequentially adding purified water and sodium hydroxide into a beaker B, stirring for 3-5 minutes until the sodium hydroxide is completely dissolved in the purified water to obtain a sodium hydroxide solution, then adding aluminum powder B into the beaker B, continuously stirring for 10-15 minutes until the aluminum powder B completely reacts with the sodium hydroxide solution to obtain two water combined with sodium metaaluminate;

s104: adding purified water into a beaker c, sequentially adding the aluminum sulfate obtained in the step S102 and the sodium metaaluminate obtained in the step S103 into the beaker c in combination with the two water, and stirring for 15-20 minutes until the aluminum sulfate and the sodium metaaluminate are completely reacted in the purified water to obtain an aluminum hydroxide precipitate and a sodium sulfate solution;

s105: filtering out the aluminum hydroxide precipitate by using filter paper, then placing the filtered aluminum hydroxide precipitate on the filter paper, and washing by using purified water;

s106: adding the washed aluminum hydroxide precipitate into a constant-temperature drying oven, drying for 15-20 minutes in the constant-temperature drying oven at the temperature of 140-150 ℃ to obtain dried aluminum hydroxide, adding the dried aluminum hydroxide into a double-sided grinder, grinding the aluminum hydroxide by the double-sided grinder, and screening by a vibrating screen to obtain aluminum hydroxide powder with the particle size of 0.074-0.4 mm.

In step S101, a 100-mesh stainless steel filter screen is used as the filter screen.

In step S102, the reaction formula of the aluminum powder a and the dilute sulfuric acid solution is:

2Al+3H₂SO₄(rare) ═ Al₂(SO₄)₃+3H₂↑。

In step S102, the weight of the aluminum powder a is 10g, the concentration of the dilute sulfuric acid solution is 10% g/ml, the volume of the dilute sulfuric acid solution is 150ml, and the dilute sulfuric acid solution contains 15g of sulfuric acid.

In step S103, the reaction formula of the aluminum powder B and the sodium hydroxide solution is:

2Al+2NaOH+6H₂0＝2Na[Al(OH)₄]+3H₂↑。

in step S103, the weight of the aluminum powder B is 10g, the weight of the sodium hydroxide is 10g, and the weight of the purified water is 30 g.

In step S104, the reaction formula of the aluminum sulfate and sodium metaaluminate in combination with two kinds of water in purified water is:

Al₂(SO₄)₃+6Na[Al(OH)₄]+12H₂O＝8Al(OH)₃↓+3Na₂(SO₄)。

in step S104, the weight ratio of the aluminum sulfate, sodium metaaluminate, two water and pure water is: 1:6:12.

Wherein, in step S105, the rinsing speed of the purified water is 0.2ml/min, and the rinsing time of the purified water is 20-25 min.

In step S106, an ultrasonic vibration sieve with a specification of Φ 2200 × 7500 is used as the vibration sieve.

Compared with the prior art, the invention has the beneficial effects that:

the preparation method comprises the steps of preparing aluminum sulfate from dilute sulfuric acid and aluminum powder, preparing sodium metaaluminate and combining two water by using a sodium hydroxide solution and the aluminum powder, reacting the aluminum sulfate and the sodium metaaluminate and combining the two water in purified water to obtain an aluminum hydroxide precipitate and a sodium sulfate solution, and sequentially filtering, washing, drying, grinding and screening to obtain the aluminum hydroxide powder with the particle size of 0.074-0.4mm, wherein the preparation method is simple and efficient; the preparation method takes aluminum powder, sodium hydroxide and dilute sulfuric acid as raw materials, the raw materials are easy to obtain, the cost is low, and the conversion rate of the aluminum hydroxide is high; simultaneously through carrying out the washing processing to the aluminium hydroxide after filtering, can reduce the impurity in the aluminium hydroxide to improve the purity of aluminium hydroxide, through carrying out grinding treatment to the aluminium hydroxide after drying, can reduce the particle diameter of aluminium hydroxide powder, reach the purpose that improves aluminium hydroxide surface area, use aluminium hydroxide in the fire retardant like this, can play better effect.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention provides the following technical scheme: a preparation method of high-flame-retardancy aluminum hydroxide micropowder comprises the following steps:

s101: selecting sufficient aluminum powder, filtering and screening the aluminum powder by using a filter screen, weighing 20g of the filtered aluminum powder, and equally dividing 20g of the aluminum powder into two parts of aluminum powder A and aluminum powder B;

s102: adding a dilute sulfuric acid solution into a beaker a, then sequentially adding aluminum powder A into the beaker a, continuously stirring, and stirring for 10-15 minutes until the aluminum powder A completely reacts with the dilute sulfuric acid solution to obtain aluminum sulfate;

s103: sequentially adding purified water and sodium hydroxide into a beaker B, stirring for 3-5 minutes until the sodium hydroxide is completely dissolved in the purified water to obtain a sodium hydroxide solution, then adding aluminum powder B into the beaker B, continuously stirring for 10-15 minutes until the aluminum powder B completely reacts with the sodium hydroxide solution to obtain two water combined with sodium metaaluminate;

s104: adding purified water into a beaker c, sequentially adding the aluminum sulfate obtained in the step S102 and the sodium metaaluminate obtained in the step S103 into the beaker c in combination with the two water, and stirring for 15-20 minutes until the aluminum sulfate and the sodium metaaluminate are completely reacted in the purified water to obtain an aluminum hydroxide precipitate and a sodium sulfate solution;

s105: filtering out the aluminum hydroxide precipitate by using filter paper, then placing the filtered aluminum hydroxide precipitate on the filter paper, and washing by using purified water;

s106: adding the washed aluminum hydroxide precipitate into a constant-temperature drying oven, drying for 15-20 minutes in the constant-temperature drying oven at the temperature of 140-150 ℃ to obtain dried aluminum hydroxide, adding the dried aluminum hydroxide into a double-sided grinder, grinding the aluminum hydroxide by the double-sided grinder, and screening by a vibrating screen to obtain aluminum hydroxide powder with the particle size of 0.074-0.4 mm.

In step S101, a 100-mesh stainless steel filter screen is used as the filter screen.

In step S102, the reaction formula of the aluminum powder a and the dilute sulfuric acid solution is:

2Al+3H₂SO₄(rare) ═ Al₂(SO₄)₃+3H₂↑。

In step S102, the weight of the aluminum powder A is 10g, the concentration of the dilute sulfuric acid solution is 10% g/ml, the volume of the dilute sulfuric acid solution is 150ml, and the dilute sulfuric acid solution contains 15g of sulfuric acid.

In step S103, the reaction formula of the aluminum powder B and the sodium hydroxide solution is:

2Al+2NaOH+6H₂0＝2Na[Al(OH)₄]+3H₂↑。

in step S103, the weight of the aluminum powder B is 10g, the weight of the sodium hydroxide is 10g, and the weight of the purified water is 30 g.

In step S104, the reaction formula of the aluminum sulfate and sodium metaaluminate in combination with two kinds of water in purified water is:

Al₂(SO₄)₃+6Na[Al(OH)₄]+12H₂O＝8Al(OH)₃↓+3Na₂(SO₄)。

in step S104, the weight ratio of the aluminum sulfate, sodium metaaluminate, two water and purified water is: 1:6:12.

Wherein, in step S105, the rinsing speed of the purified water is 0.2ml/min, and the rinsing time of the purified water is 20-25 min.

In step S106, an ultrasonic vibration sieve having a specification of Φ 2200 × 7500 is used as the vibration sieve.

Experimental example, flame retardancy test.

Experimental groups: s1, selecting 100g of the aluminum hydroxide powder prepared by the method, and dividing 100g of the aluminum hydroxide powder into 10 parts, wherein each part is 10g of the aluminum hydroxide powder;

s2, selecting 2000g of plastic particles, and equally dividing 2000g of plastic particles into 10 parts, wherein each part is 200g of plastic particles;

s3, respectively adding 10 parts of aluminum hydroxide powder into 10 parts of plastic particles, wherein each part of plastic particles contains 10g of aluminum hydroxide powder, and uniformly mixing the aluminum hydroxide powder into the plastic particles;

s4, 10 parts of the plastic particles mixed with the aluminum hydroxide powder are made into plastic plates (the plastic plates have the same size structure), and then the plastic plates are placed at 150 ℃ to record the melting time and burning time of the plastic plates, which are detailed in table 1.

Control group: s1, selecting 10g of aluminum hydroxide powder and 200g of plastic particles which are common in the market;

s2, respectively adding aluminum hydroxide powder into the plastic particles, and uniformly mixing the aluminum hydroxide powder into the plastic particles;

s3, preparing plastic particles mixed with aluminum hydroxide powder into plastic plates (the size of the plastic plates is the same as that of the plastic plates of the practical group), placing the prepared plastic plates at 150 ℃, and recording the melting time and burning time of the plastic plates, which are detailed in table 1.

TABLE 1

As can be seen from the above table, after the aluminum hydroxide powder prepared by the invention is added into the plastic, the melting time and the burning time of the plastic plate are both obviously improved, so the aluminum hydroxide prepared by the invention has better flame retardant effect.

In conclusion, the aluminum sulfate is prepared by dilute sulfuric acid and aluminum powder, then the sodium metaaluminate combined water is prepared by the sodium hydroxide solution and the aluminum powder, then the aluminum hydroxide precipitate and the sodium sulfate solution are obtained by the reaction of the aluminum sulfate and the sodium metaaluminate combined water in purified water, and then the aluminum hydroxide powder with the particle size of 0.074-0.4mm is obtained by filtering, washing, drying, grinding and screening in sequence; the preparation method takes aluminum powder, sodium hydroxide and dilute sulfuric acid as raw materials, the raw materials are easy to obtain, the cost is low, and the conversion rate of the aluminum hydroxide is high; simultaneously through carrying out the washing processing to the aluminium hydroxide after filtering, can reduce the impurity in the aluminium hydroxide to improve the purity of aluminium hydroxide, through carrying out grinding treatment to the aluminium hydroxide after drying, can reduce the particle diameter of aluminium hydroxide powder, reach the purpose that improves aluminium hydroxide surface area, use aluminium hydroxide in the fire retardant like this, can play better effect.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

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