阅读说明：本技术 一种工业级氢氧化镁微波法制备阻燃剂用氢氧化镁的方法 (Method for preparing magnesium hydroxide for flame retardant by industrial-grade magnesium hydroxide microwave method ) 是由 曹雨微 宋学文 刘远 孔会民 王铧泰 逯登琴 于 2021-02-18 设计创作，主要内容包括：本发明公开了一种工业级氢氧化镁微波法制备阻燃剂用氢氧化镁的方法,称量好工业氢氧化镁和水氯镁石转入消解罐中,加入蒸馏水,放入微波消解仪进行微波处理,使得工业氢氧化镁溶解-再结晶,处理后的氢氧化镁产品进行过滤、洗涤、干燥,最终获得形貌规则、低极性氢氧化镁。本发明以工业氢氧化镁为原料,水氯镁石为添加剂,其生产效率高,工艺流程简单可控,制备时间短、成本低。在未使用碱性添加剂(氢氧化钠、氢氧化钾等)的条件下,利用微波快速制备形貌规则、低极性氢氧化镁。通过本发明制得的产品粒径分布窄(0.8μm-8μm)、粒径小(D-(50)＝1.44μm,D-(90)＝2.07μm),极性低(I-(001)/I-(101)＞1),具有极大的应用价值和市场价值。(The invention discloses a method for preparing magnesium hydroxide for a flame retardant by an industrial-grade magnesium hydroxide microwave method. The invention takes industrial magnesium hydroxide as a raw material and bischofite as an additive, and has the advantages of high production efficiency, simple and controllable process flow, short preparation time and low cost. Under the condition of not using alkaline additives (sodium hydroxide, potassium hydroxide and the like), the magnesium hydroxide with regular shape and low polarity is quickly prepared by utilizing microwave. The product prepared by the invention has narrow particle size distribution (0.8-8 μm) and small particle size (D) 50 ＝1.44μm，D 90 2.07 μm), low polarity (I) 001 /I 101 ＞1)Has great application value and market value.)

1. A method for preparing magnesium hydroxide for a flame retardant by an industrial-grade magnesium hydroxide microwave method is characterized by comprising the following steps: the method comprises the following steps of (1),

A. weighing industrial-grade magnesium hydroxide and bischofite, transferring the weighed industrial-grade magnesium hydroxide and bischofite into an analysis tank of a microwave analyzer, and adding distilled water into the analysis tank;

B. treating industrial magnesium hydroxide, bischofite and distilled water at a certain temperature and under a certain microwave power for a period of time to dissolve and recrystallize the industrial magnesium hydroxide;

C. and filtering the product obtained by the reaction to obtain a filter cake, and washing and drying the filter cake to obtain the magnesium hydroxide with regular shape and low polarity.

2. The method for preparing magnesium hydroxide for flame retardant by industrial grade magnesium hydroxide microwave method according to claim 1, characterized in that: in the step A, the amount of the industrial grade magnesium hydroxide is 0.4 to 5 parts, the amount of the bischofite is 0.02 to 10 parts, and the addition amount of the distilled water is 1 to 25 parts.

3. The method for preparing magnesium hydroxide for flame retardant by industrial grade magnesium hydroxide microwave method according to claim 1, characterized in that: in step A, the mass of technical grade magnesium hydroxide was 1g, the mass of bischofite was 3g, and the amount of distilled water added was 25 mL.

4. The method for preparing magnesium hydroxide for flame retardant by industrial grade magnesium hydroxide microwave method according to claim 1, characterized in that: in the step A, the solid content of the magnesium hydroxide is 1 to 20 percent; the molar concentration of the bischofite is 0.004-2 mol/L.

5. The method for preparing magnesium hydroxide for flame retardant by industrial grade magnesium hydroxide microwave method according to claim 1, characterized in that: in the step B, the industrial grade magnesium hydroxide and bischofite are reacted in a microwave analyzer at the temperature of 160 ℃ and the power of 1600W for 60 min.

6. The method for preparing magnesium hydroxide for flame retardant by industrial grade magnesium hydroxide microwave method according to claim 1, characterized in that: in step C, the prepared filter cake is washed 2-3 times.

7. The method for preparing magnesium hydroxide for flame retardant by industrial grade magnesium hydroxide microwave method according to claim 1, characterized in that: the average grain diameter of the industrial grade magnesium hydroxide is 1.5-2 mu m.

Technical Field

The invention relates to the technical field of synthesis of magnesium hydroxide flame retardants, in particular to a method for preparing magnesium hydroxide for flame retardants by microwave treatment.

Background

The magnesium hydroxide has the advantages of no toxicity, high thermal stability, safety, environmental protection and the like, has regular appearance and low polarity, has higher application value, can be applied to high polymer materials with the function of a flame retardant, can also be applied to preparation of magnesium oxide, has high activity after light burning, and can be used for adsorption or low-temperature sintering. The magnesium hydroxide prepared by the traditional precipitation method is difficult to control in the reaction process, and the formed magnesium hydroxide is irregular, large in polarity, easy to agglomerate, large in particle size and wide in distribution, and is not beneficial to direct application.

The wide solution is to adopt a hydrothermal method, the hydrothermal process provides a certain temperature for a preparation system, and a mineralizer with a certain concentration can dissolve and recrystallize magnesium hydroxide to obtain magnesium hydroxide with regular appearance and low polarity. However, the hydrothermal method needs resistance heating or gas and fuel oil to provide heat, the heating process is long in time, and heating is not uniform. The microwave technology breaks the defect of the hydrothermal process, can rapidly and uniformly provide heat for a reaction system, and achieves the same dissolving and recrystallizing purposes as the hydrothermal method. Meanwhile, compared with an energy source required by hydrothermal, the microwave technology has the advantages of less energy consumption, no exhaust gas discharge and environmental friendliness.

Disclosure of Invention

The technical problem to be solved by the invention is to provide the method for preparing the magnesium hydroxide for the flame retardant by the industrial-grade magnesium hydroxide microwave method, which is simple in process flow, high in production efficiency and more environment-friendly, and can reduce the polarity and the particle size and the distribution range in a short time by treating the industrial magnesium hydroxide.

In order to solve the technical problems, the invention adopts the following technical scheme: a method for preparing magnesium hydroxide for a flame retardant by an industrial-grade magnesium hydroxide microwave method is characterized by comprising the following steps: the method comprises the following steps of (1),

A. weighing industrial-grade magnesium hydroxide and bischofite, transferring the weighed industrial-grade magnesium hydroxide and bischofite into an analysis tank of a microwave analyzer, and adding distilled water into the analysis tank;

B. treating industrial magnesium hydroxide, bischofite and distilled water at a certain temperature and under a certain microwave power for a period of time to dissolve and recrystallize the industrial magnesium hydroxide;

C. and filtering the product obtained by the reaction to obtain a filter cake, and washing and drying the filter cake to obtain the magnesium hydroxide with regular shape and low polarity.

In the step A, the amount of the industrial grade magnesium hydroxide is 0.4 to 5 parts, the amount of the bischofite is 0.02 to 10 parts, and the addition amount of the distilled water is 1 to 25 parts.

In step A, the mass of technical grade magnesium hydroxide was 1g, the mass of bischofite was 3g, and the amount of distilled water added was 25 mL.

In the step A, the solid content of the magnesium hydroxide is 1 to 20 percent; the molar concentration of bischofite is 0.004-2mol/L, such as 0.6 mol/L.

In step B, the industrial magnesium hydroxide and bischofite are reacted in a microwave analyzer at 160 ℃ and 1600W for 60min (with some differences).

In step C, the prepared filter cake is washed 2-3 times.

The average grain diameter of the industrial grade magnesium hydroxide is 1.5-2 mu m.

Since the prior art has adopted bischofite (MgCl)₂·6H₂O) as promoting technical gradeThe invention relates to a mineralizer hydrothermal technology for dissolving magnesium hydroxide, which uses a microwave analyzer to provide rapid and uniform heating through microwaves so as to dissolve and recrystallize industrial-grade magnesium hydroxide and finally obtain low-polarity magnesium hydroxide with smaller particle size, narrower particle size distribution and regular appearance.

The method takes industrial-grade magnesium hydroxide as a raw material, and the industrial-grade magnesium hydroxide and bischofite in a certain mass ratio are added into a microwave analyzer device to react at a certain temperature and power to prepare the magnesium hydroxide with low polarity, small particle size, narrow distribution and regular appearance; the process flow is simple, the temperature rise time is shortened from dozens of minutes to several minutes, and the problem of high cost of the dissolution-recrystallization time of the magnesium hydroxide is solved while the preparation of the magnesium hydroxide with high application value is realized. Taking resistance heating as an example, 30min is needed for heating to 160 ℃, and 8min is needed for microwave heating); the magnesium hydroxide product prepared by the method has high purity, narrow particle size distribution (0.8-5 mu m), and D₅₀1.44 μm, D₉₀2.07 mu m, regular shape (needle shape and sheet shape), and great application value and market value.

Drawings

FIG. 1 is XRD (X-ray diffraction) pattern and SEM (scanning Electron microscope) pattern of magnesium hydroxide prepared by the invention.

Detailed Description

The invention is further illustrated by the following specific examples:

example 1

0.4g of technical-grade magnesium hydroxide (average particle diameter: 1.88 μm) and 0.02g of bischofite were weighed, 25mL of distilled water was measured, and the solution was charged into a 50mL analytical pot. Sealing the analysis tank, closing the door, adjusting the temperature to 160 deg.C, power 1600W, heating for 5min, and holding for 30 min. After the preparation is ready, the microwave analyzer device is started. And (3) carrying out suction filtration and washing on the product subjected to microwave treatment for 3 times, and then drying at 105 ℃ for 2 hours to obtain the magnesium hydroxide with regular shape and low polarity. Calculated, microwave treated magnesium hydroxide I₀₀₁/I₁₀₁And I₀₀₁/I₁₁₀1.00 and 4.27 respectively.

Example 2

Weigh 1g of technical gradeMagnesium hydroxide (average particle diameter: 1.88 μm) and 3.0473g of bischofite, 25mL of distilled water was measured and charged into a 50mL resolving pot. Sealing the analysis tank, closing the door, adjusting temperature to 160 deg.C, power 1600W, heating for 5min, holding for 20min, cooling to 70 deg.C after microwave stop, heating for 5min and holding for 20min, and repeating the treatment for 6 times by cooling and heating method. Obtaining the low-polarity magnesium hydroxide. Calculated, microwave treated magnesium hydroxide I₀₀₁/I₁₀₁And I₀₀₁/I₁₁₀1.50 and 6.80 respectively.

Example 3

5g of technical-grade magnesium hydroxide (average particle diameter: 1.88 μm) and 3.0498g of bischofite were weighed, 25mL of distilled water was weighed, and the weighed solution was charged into a 50mL resolving pot. Sealing the analysis tank, closing the door, adjusting the temperature to 160 deg.C, power 1600W, heating for 5min, maintaining the temperature at 160 deg.C for 30min, maintaining the temperature at 150 deg.C for 15min, and maintaining the temperature at 140 deg.C for 15 min. After the preparation is ready, the microwave analyzer device is started. And (3) carrying out suction filtration and washing on the product subjected to microwave treatment for 3 times, and then drying at 105 ℃ for 2 hours to obtain the low-polarity magnesium hydroxide. Calculated, microwave treated magnesium hydroxide I₀₀₁/I₁₀₁And I₀₀₁/I₁₁₀1.62 and 6.92, respectively, which was confirmed by X-ray diffraction experiments to be a magnesium hydroxide with low surface polarity, as shown in fig. 1.

The present invention has been described in detail, and it should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.