阅读说明：本技术 聚磷酸铵制备细粒径控制方法及其应用 (Method for controlling fine particle size in preparation of ammonium polyphosphate and application thereof ) 是由 裘雪阳 朱峰 徐玲 陈建军 于 2020-05-25 设计创作，主要内容包括：本发明提供一种聚磷酸铵制备细粒径控制方法及其应用。方法包括反应步骤、冷却步骤及粉碎步骤。反应步骤：将摩尔比为1：1的五氧化二磷和磷酸氢二铵搅拌均匀,加热通氨,通氨量为0.5 m3/h-2.5m3/h,升温到150℃-200℃后,调节通氨量为1.0 m3/h-4.0m3/h,继续温度升到260℃-310℃,反应2h-5h；当反应物内温稳定了5min-15min后,加入0.5%-3%的缺氨聚磷酸铵粉末；冷却步骤：停止加热,降低通氨量,通氨量为0.2 m3/h~1m3/h,冷却1~2h,得到聚磷酸铵粗产品；粉碎步骤：采用空气分级磨粉碎机粉碎聚磷酸铵粗产品,得到控制细粒径的结晶II型聚磷酸铵产品。(The invention provides a method for controlling the fine particle size of ammonium polyphosphate preparation and application thereof. The method comprises a reaction step, a cooling step and a crushing step. The reaction steps are as follows: mixing a mixture of 1: uniformly stirring the phosphorus pentoxide and the diammonium phosphate of 1, heating for ammonia introduction, carrying out thin film evaporation at 0.5 m/h-2.5 m/h, heating to 150-200 ℃, adjusting for ammonia introduction to 1.0 m/h-4.0 m, carrying out thin film evaporation at 260-310 ℃, and reacting for 2-5 h; when the temperature in the reactant is stabilized for 5min-15min, 0.5% -3% of ammonia-deficient ammonium polyphosphate powder is added; and (3) cooling: stopping heating, reducing ammonia flow, carrying out thin film evaporation at 0.2-1 m, and cooling for 1-2 h to obtain a coarse ammonium polyphosphate product; a crushing step: and (3) crushing the coarse ammonium polyphosphate product by adopting an air classification mill crusher to obtain a crystal II type ammonium polyphosphate product with a controlled fine particle size.)

1. A method for controlling the fine particle size of ammonium polyphosphate is characterized by comprising the following steps:

the reaction steps are as follows: mixing a mixture of 1:1, stirring the phosphorus pentoxide and the diammonium hydrogen phosphate uniformly, heating and introducing ammonia, wherein the ammonia introducing amount is 0.5m³/h-2.5m³H, heating to 150-200 ℃, and adjusting the ammonia introducing amount to 1.0m³/h-4.0m³The temperature is continuously raised to 260-310 ℃ and the reaction lasts for 2-5 h; when the temperature in the reactant is stable for 5min-15min, 0.5% -3% of ammonia-deficient ammonium polyphosphate powder is added;

and (3) cooling: stopping heating, reducing ammonia flow to 0.2m³/h～1m³Cooling for 1-2 h to obtain an ammonium polyphosphate crude product;

a crushing step: and (3) crushing the coarse ammonium polyphosphate product by adopting an air classification mill crusher to obtain a crystal II type ammonium polyphosphate product with a controlled fine particle size.

2. The fine particle size control method for preparing ammonium polyphosphate according to claim 1, wherein the ammonia-deficient ammonium polyphosphate powder is prepared by the following method:

adding 120 kg of phosphorus pentoxide and 113 kg of diammonium hydrogen phosphate into a kneader, uniformly stirring at the rotating speed of 60RPM, heating, introducing ammonia with the ammonia introduction amount of 8.0m³H, when the temperature is raised to 250 ℃, forming thick syrup-like liquid, and keeping the reaction for 2h when the final temperature reaches 300 ℃; the ammonia amount is reduced to 1.5m³Reacting for 3 hours, and gradually reducing the reaction temperature to 240 ℃ to obtain white crystal II type ammonium polyphosphate solid powder; adding white crystal II type ammonium polyphosphate solid powder into a kneader, stirring at 150RPM, introducing nitrogen gas at a flow rate of 0.3m³And h, keeping the temperature for 3h after the temperature is raised to 220 ℃, and cooling and crushing to obtain ammonium-deficient ammonium polyphosphate powder.

3. The fine particle size control method for ammonium polyphosphate preparation according to claim 2, wherein the ammonia-deficient ammonium polyphosphate powder added in the reaction step is 1-1.7%.

4. The fine particle size control method for ammonium polyphosphate preparation according to claim 3, wherein the ammonia-deficient ammonium polyphosphate powder has a D50 of 5 μm to 10 μm.

5. The fine particle size control method for preparing ammonium polyphosphate according to claim 4, wherein the D50 of the ammonia-deficient ammonium polyphosphate powder is 5-6 μm.

6. The method for controlling the fine particle size in the preparation of ammonium polyphosphate according to any one of claims 1 to 5, wherein the feeding frequency of the air classification mill pulverizer is 15 HZ-20 HZ, the internal division frequency is 30 HZ-50 HZ, and the fan frequency is 30 HZ-45 HZ.

7. The method for controlling the fine particle size of ammonium polyphosphate prepared according to any one of claims 1 to 5, wherein the content of phosphorus pentoxide is not less than 99.5%, the activity R value is not less than 1.7, and the proportion of reducing substances is not more than 0.005%.

8. The method for controlling the fine particle size in the preparation of ammonium polyphosphate according to claim 1, wherein the proportion of the crystal form II ammonium polyphosphate product with the particle size of not more than 2.19 μm in the fine particle size is not more than 2%.

9. The application of the crystal II type ammonium polyphosphate product with the controlled fine particle size is characterized in that the crystal II type ammonium polyphosphate product with the controlled fine particle size is prepared by the method for controlling the fine particle size by using the ammonium polyphosphate according to any one of claims 1 to 8, and the crystal II type ammonium polyphosphate product with the controlled fine particle size is used as a flame retardant in a steel structure fireproof coating.

10. The use of a controlled fine particle size crystalline form II ammonium polyphosphate product as claimed in claim 9 wherein the controlled fine particle size crystalline form II ammonium polyphosphate product is present in a fire retardant coating in an amount of 24% by weight.

Technical Field

The invention relates to the technical field of ammonium polyphosphate preparation, in particular to a fine particle size control method for ammonium polyphosphate preparation and application thereof.

Background

Ammonium polyphosphate (APP) is a biodegradable phosphorus and nitrogen type environment-friendly inorganic flame retardant, can be used as a flame retardant for paint, plastic and rubber, and has a plurality of crystal structures, wherein I, II are the most commonly used ones, and the performance of crystal II is better. Therefore, the flame retardant has wide application in the flame retardant fields of fire retardant coatings, resins, rubber paper, wood, fibers and the like, and has the characteristics of low toxicity and low smoke. The ammonium polyphosphate is an important component of the steel structure intumescent fire-retardant coating, has high requirements on viscosity and storage stability, and has specific requirements on the performance and particle size of various raw materials.

The known preparation method of the electronic-grade ammonium polyphosphate flame retardant is characterized in that diammonium hydrogen phosphate and phosphorus pentoxide are ground and mixed, ammonia is introduced, a three-stage heating process is adopted, and then a polyurethane coating material is modified to obtain the electronic-grade ammonium polyphosphate with the particle size of 500 meshes. The method is mainly used for preparing the APP with the fine particle size, and meanwhile, the grinding of the raw materials has certain hygroscopicity to influence the product performance. The method of grinding ammonium polyphosphate in a solvent and modifying the ammonium polyphosphate with a triazine flame retardant is also adopted to control the particle size of the product.

Another known preparation method of high heat resistance crystal II type ammonium polyphosphate adopts the mixed reaction of diammonium hydrogen phosphate and phosphorus pentoxide, and sprays high-concentration urea solution after ammonia is introduced, and the product produced by the method has small grain size, and the average grain size is less than 10 microns. A large amount of water in the urea solution not only influences the condensation reaction in the synthesis process, but also increases the energy consumption due to the escape of a large amount of water.

In addition, the preparation method of crystal II type ammonium polyphosphate with high polymerization degree and narrow molecular weight distribution adopts the mixed reaction of diammonium hydrogen phosphate and phosphorus pentoxide with equal mol, and a large amount of inert gas is introduced in the initial process, and ammonium polyphosphate products (less than 12 microns) with fine particle size are obtained by introducing, stopping and repeatedly introducing ammonia gas, and carrying out reaction through surface treatment. Inert gases such as nitrogen, helium, argon and the like need to be introduced in the preparation process of the product, so that the production cost is increased, and the whole particle size of the product is small.

Disclosure of Invention

The invention aims to provide a method for controlling the fine particle size of ammonium polyphosphate preparation and application thereof.

In order to solve the technical problems, the method for controlling the fine particle size of the ammonium polyphosphate comprises a reaction step, a cooling step and a crushing step.

The reaction steps are as follows: mixing a mixture of 1: uniformly stirring the phosphorus pentoxide and the diammonium phosphate of 1, heating for ammonia introduction, carrying out thin film evaporation at 0.5 m/h-2.5 m/h, heating to 150-200 ℃, adjusting for ammonia introduction to 1.0 m/h-4.0 m, carrying out thin film evaporation at 260-310 ℃, and reacting for 2-5 h; when the temperature in the reactant is stabilized for 5min-15min, 0.5% -3% of ammonia-deficient ammonium polyphosphate powder is added;

and (3) cooling: stopping heating, reducing ammonia flow, carrying out thin film evaporation at 0.2-1 m, and cooling for 1-2 h to obtain a coarse ammonium polyphosphate product;

a crushing step: and (3) crushing the coarse ammonium polyphosphate product by adopting an air classification mill crusher to obtain a crystal II type ammonium polyphosphate product with a controlled fine particle size.

Optionally, the ammonia-deficient ammonium polyphosphate powder is prepared by the following method:

adding 120 kg of phosphorus pentoxide and 113 kg of diammonium hydrogen phosphate into a kneader, uniformly stirring at the rotating speed of 60RPM, heating, introducing ammonia at the introduction amount of 8.0m3/h, heating to 250 ℃ to obtain viscous syrup-like liquid, and keeping the reaction temperature at 300 ℃ for 2 h; reducing the ammonia flow to 1.5m 3/h, reacting for 3h, and gradually reducing the reaction temperature to 240 ℃ to obtain white crystal II type ammonium polyphosphate solid powder; adding white crystal II type ammonium polyphosphate solid powder into a kneader, stirring at the speed of 150RPM, introducing nitrogen at the flow rate of 0.3m3/h, keeping the temperature for 3h after the temperature is raised to 220 ℃, cooling and crushing to obtain the ammonium-deficient ammonium polyphosphate powder.

Optionally, the ammonia-deficient ammonium polyphosphate powder added in the reaction step is 1-1.7%.

Optionally, D50 of the ammonia-deficient ammonium polyphosphate powder is 5-10 μm.

Furthermore, the D50 of the ammonia-deficient ammonium polyphosphate powder is 5-6 mu m.

Optionally, the feeding frequency of the air classification mill pulverizer is 15 HZ-20 HZ, the internal division frequency is 30 HZ-50 HZ, and the fan frequency is 30 HZ-45 HZ.

Optionally, the content of phosphorus pentoxide is more than or equal to 99.5%, the activity R value is more than or equal to 1.7, and the proportion of reducing substances is less than or equal to 0.005%.

Optionally, the proportion of the crystal II type ammonium polyphosphate product with the grain size of less than or equal to 2.19 mu m in the fine grain size is controlled to be less than or equal to 2 percent.

The invention also provides an application of the crystal II type ammonium polyphosphate product for controlling the fine particle size, the crystal II type ammonium polyphosphate product for controlling the fine particle size is prepared by any method for preparing the fine particle size from the ammonium polyphosphate, and the crystal II type ammonium polyphosphate product for controlling the fine particle size is used as a flame retardant in the steel structure fireproof coating.

Optionally, the mass ratio of the crystal II type ammonium polyphosphate product with fine particle size in the fireproof coating is controlled to be 24%.

In conclusion, the invention can control the proportion of the fine particle size of the final product without introducing a large amount of inert gas, urea containing a large amount of moisture and grinding the raw materials, and the crystal II type ammonium polyphosphate product with the proportion of the fine particle size of less than or equal to 2.19 mu m of less than or equal to 2 percent is used as a flame retardant in the steel structure fireproof coating.

Detailed Description

The following examples are given to further illustrate the embodiments of the present invention. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The percentages referred to in the present invention are all mass percentages. For example, 0.5% -3% of the ammonia-deficient ammonium polyphosphate powder is added, which means that the ammonia-deficient ammonium polyphosphate powder accounts for 0.5% -3% of the mass of the total reactants.