阅读说明：本技术 一种光学级偏磷酸镁的制备方法 (Preparation method of optical-grade magnesium metaphosphate ) 是由 蒋加富 于 2020-04-10 设计创作，主要内容包括：本发明技术方案提供了一种光学级偏磷酸镁的制备方法,包括如下步骤：将氢氧化镁或氧化镁与磷酸、水按一定比例发生反应,得到粗磷酸二氢镁溶液；调节粗磷酸二氢镁溶液的浓度,使其经过离子交换树脂,以脱除有色金属和杂质离子；将经过离子交换树脂后的溶液蒸发浓缩,获得浓度在30％以上的提浓液；洁净煅烧,以脱除游离水和结构水,得到光学级偏磷酸镁。本发明技术方案的制备方法对于原料氢氧化镁或氧化镁的适应性强,采用离子交换法并结合洁净喷雾煅烧可制备出高纯度的偏磷酸镁,各项指标均满足光学玻璃和激光玻璃原料的要求。(The technical scheme of the invention provides a preparation method of optical-grade magnesium metaphosphate, which comprises the following steps: reacting magnesium hydroxide or magnesium oxide with phosphoric acid and water according to a certain proportion to obtain a crude magnesium dihydrogen phosphate solution; adjusting the concentration of the crude magnesium dihydrogen phosphate solution, and passing the solution through ion exchange resin to remove nonferrous metals and impurity ions; evaporating and concentrating the solution after ion exchange resin to obtain concentrated solution with the concentration of more than 30%; and (4) clean calcining to remove free water and structural water to obtain the optical-grade magnesium metaphosphate. The preparation method of the technical scheme of the invention has strong adaptability to the raw material magnesium hydroxide or magnesium oxide, high-purity magnesium metaphosphate can be prepared by adopting an ion exchange method and combining clean spray calcination, and all indexes meet the requirements of optical glass and laser glass raw materials.)

1. A preparation method of optical-grade magnesium metaphosphate is characterized by comprising the following steps:

1) reacting magnesium hydroxide or magnesium oxide with phosphoric acid and water according to a certain proportion to obtain a crude magnesium dihydrogen phosphate solution;

2) adjusting the concentration of the crude magnesium dihydrogen phosphate solution, and passing the solution through ion exchange resin to remove nonferrous metals and impurity ions;

3) evaporating and concentrating the solution after ion exchange resin to obtain concentrated solution with the concentration of more than 30%;

4) and (4) clean calcining to remove free water and structural water to obtain the optical-grade magnesium metaphosphate.

2. The method for preparing optical-grade magnesium metaphosphate according to claim 1, wherein in step 1), the molar ratio of magnesium hydroxide or magnesium oxide to said phosphoric acid is 1 (1.97-2.05), and the mass ratio of phosphoric acid to water is 1 (1.5-3.0).

3. The process for preparing optical-grade magnesium metaphosphate according to claim 1 or 2, wherein in step 1), the reaction temperature is 125-145 ℃, the reaction pressure is 0.3-0.55 MPa, and the reaction time is 3-7 h.

4. The process for preparing optical grade magnesium metaphosphate of claim 1, wherein the concentration of the crude magnesium dihydrogen phosphate solution is adjusted to 8% -18%, and the flow rate through the ion exchange resin is 1.5L/min-5L/min.

5. The process of claim 1 wherein the ion exchange resin comprises a cation exchange resin comprising one or a combination of 732, 741, 001 × 7, D403, iorrein 1200, iorrein 252 and an anion exchange resin comprising one or a combination of 201 × 4, D202, D406, iorrein IRA402, iorrein IRA 900.

6. The process for preparing optical-grade magnesium metaphosphate according to claim 1, wherein in step 3), the concentration of the concentrated solution is 30% -40%, the temperature of the reduced pressure concentration is 105-125 ℃, and the vacuum degree is-0.05 MPa-0.08 MPa.

7. The process of claim 1, wherein the concentrated magnesium dihydrogen phosphate solution is introduced into a spray calcining tower at a flow rate of 6L/min to 13L/min for clean calcination, wherein the inlet air temperature is 600 ℃ to 700 ℃, the upper section temperature of the tower body is 560 ℃ to 650 ℃, the middle section temperature of the tower body is 520 ℃ to 630 ℃, the lower section temperature of the tower body is 500 ℃ to 590 ℃, and the outlet air temperature is 340 ℃ to 420 ℃.

8. The method for preparing optical-grade magnesium metaphosphate of claim 7, wherein the material contact part in the spray calcination tower is lined with high-purity alumina, the spray head is made of titanium-palladium alloy, and the heating mode is indirect heating.

Technical Field

The invention relates to the field of fine inorganic phosphorus chemical industry, in particular to a preparation method of optical-grade magnesium metaphosphate.

Background

Metaphosphate is the most stable phosphate among dibasic phosphates, and is a basic raw material for the production of phosphate glass. The high-purity metaphosphate has excellent light transmittance, so that the metaphosphate can be used as an important raw material of laser glass in a high-power laser (such as national scientific engineering-Shenguang plan) and also can be used as an important raw material of some advanced optical equipment such as camera lenses, high-definition cameras, smart phone lenses and mobile phone panel substrates. The transition metals of Fe, Co, Ni and the like can cause strong absorption of metaphosphate glass in the near ultraviolet to infrared regions, and the optical performance of the glass is influenced. Therefore, the preparation of high purity metaphosphate raw material becomes the key to the manufacture of high performance laser glass.

Although China is a large country for producing phosphorus chemical industry, the development of high-additive and fine phosphorus chemical industry products is lagged, and the competitiveness of the international market is lacked. In view of technical blockade of international peers, the economic benefits of enterprises can be improved only by independent innovation, deep development of refined phosphorus chemical products is enhanced, high-tech content of the products is improved, and additional value of the products is improved.

Disclosure of Invention

In view of the above-mentioned current state of the art, the technical problem to be solved by the present invention is to provide a method for preparing optical grade magnesium metaphosphate, wherein the main index of the prepared magnesium metaphosphate can meet the requirement of manufacturing optical glass and laser glass.

In order to solve the technical problems, the technical scheme of the invention provides a preparation method of optical-grade magnesium metaphosphate, which comprises the following steps:

1) reacting magnesium hydroxide or magnesium oxide with phosphoric acid and water according to a certain proportion to obtain a crude magnesium dihydrogen phosphate solution;

2) adjusting the concentration of the crude magnesium dihydrogen phosphate solution, and passing the solution through ion exchange resin to remove nonferrous metals and impurity ions;

3) evaporating and concentrating the solution after ion exchange resin to obtain concentrated solution with the concentration of more than 30%;

4) and (4) clean calcining to remove free water and structural water to obtain the optical-grade magnesium metaphosphate.

The magnesium hydroxide, magnesium oxide and phosphoric acid may all be selected from technical grade raw materials.

Preferably, in the step 1), the molar ratio of the magnesium hydroxide or magnesium oxide to the phosphoric acid is 1 (1.97-2.05), and the mass ratio of the phosphoric acid to the water is 1 (1.5-3.0). Preferably, the molar ratio of the magnesium hydroxide or magnesium oxide to the phosphoric acid is 1 (1.99-2.02), and the mass ratio of the phosphoric acid to the water is 1 (1.8-2.5).

Preferably, in the step 1), the reaction temperature is 125-145 ℃, the reaction pressure is 0.3-0.55 MPa, and the reaction time is 3-7 h. Further preferably, the reaction temperature is 130-140 ℃, the reaction pressure is 0.35-0.48 MPa, and the reaction time is 4.5-6 h.

Preferably, the concentration of the crude magnesium dihydrogen phosphate solution is adjusted to 8 to 18 percent, and the flow rate through the ion exchange resin is 1.5L/min to 5L/min, further preferably, the concentration of the crude magnesium dihydrogen phosphate solution is adjusted to 8 to 13 percent, and the flow rate through the ion exchange resin is 2L/min to 4L/min.

Preferably, the ion exchange resin comprises cation exchange resin and anion exchange resin, the cation exchange resin comprises 732, 741, 001 × 7, D403, IONRESIN 1200 and IONRESIN 252, and the anion exchange resin comprises 201 × 4, D202, D406, IONRESIN IRA402 and IONRESIN IRA900, or a combination thereof.

Preferably, in the step 3), the concentrated solution is obtained by adopting a reduced pressure evaporation concentration mode, the concentration of the concentrated solution is 30-40%, the temperature of the reduced pressure concentration is 105-125 ℃, and the vacuum degree is-0.05 MPa-0.08 MPa. More preferably, the concentration is carried out to 30 to 35 percent, the temperature of the reduced pressure concentration is 105 to 115 ℃, and the vacuum degree is-0.04 MPa to-0.07 MPa.

Preferably, the concentrated magnesium dihydrogen phosphate solution enters a spray calcining tower at the flow rate of 6L/min to 13L/min for clean calcining, wherein the air inlet temperature is 600 ℃ to 700 ℃, the upper section temperature of the tower body is 560 ℃ to 650 ℃, the middle section temperature of the tower body is 520 ℃ to 630 ℃, the lower section temperature of the tower body is 500 ℃ to 590 ℃, and the air outlet temperature is 340 ℃ to 420 ℃.

Further, the concentrated magnesium dihydrogen phosphate solution enters a spray calcining tower at the flow rate of 8L/min-12L/min for clean calcining, wherein the air inlet temperature is 650-680 ℃, the upper section temperature of the tower body is 620-650 ℃, the middle section temperature of the tower body is 590-615 ℃, the lower section temperature of the tower body is 550-590 ℃, and the air outlet temperature is 350-380 ℃.

The preparation method of the optical-grade magnesium metaphosphate in the technical scheme of the invention has the following beneficial effects: the adaptability to magnesium hydroxide or magnesium oxide as raw materials is strong, the ion exchange method is adopted to remove impurities, the ion exchange method is adopted and combined with clean spray calcination, high-purity magnesium metaphosphate can be prepared, and all indexes meet the requirements of optical glass and laser glass raw materials.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

Fig. 1 is a flow chart of a method for preparing optical-grade magnesium metaphosphate according to the technical scheme of the invention.

Detailed Description

The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.

As shown in fig. 1, the method for preparing optical-grade magnesium metaphosphate according to the present invention comprises the following steps:

1) reacting magnesium hydroxide or magnesium oxide with phosphoric acid and water according to a certain proportion to obtain a crude magnesium dihydrogen phosphate solution;

2) adjusting the concentration of the crude magnesium dihydrogen phosphate solution, and passing the solution through ion exchange resin to remove nonferrous metals and impurity ions;

3) evaporating and concentrating the solution after ion exchange resin to obtain concentrated solution with the concentration of more than 30%;

4) and (4) clean calcining to remove free water and structural water to obtain the optical-grade magnesium metaphosphate.