阅读说明：本技术 一种光学级偏磷酸锌的制备方法 (Preparation method of optical-grade zinc metaphosphate ) 是由 蒋加富 于 2020-05-15 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锌的制备方法,包括如下步骤：配置磷酸二氢铵水溶液,并除去水不溶物；经过离子交换装置,以脱除有色金属和杂质离子；并结合环保氧化锌与光学级磷酸二氢铵固固中-高温两段法洁净煅烧反应,可制备得到光学级偏磷酸锌。本发明技术方案的制备方法对于原料的适应性较强,制备的光学级偏磷酸锌的主要技术指标均满足光学级原料的要求。(The technical scheme of the invention provides a preparation method of optical grade zinc metaphosphate, which comprises the following steps: preparing an ammonium dihydrogen phosphate aqueous solution, and removing water insoluble substances; removing nonferrous metals and impurity ions by an ion exchange device; and the optical grade zinc metaphosphate can be prepared by combining the clean calcination reaction of the environment-friendly zinc oxide and the optical grade ammonium dihydrogen phosphate solid medium-high temperature two-stage method. The preparation method of the technical scheme of the invention has stronger adaptability to raw materials, and the main technical indexes of the prepared optical grade zinc metaphosphate all meet the requirements of optical grade raw materials.)

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

(1) preparing an ammonium dihydrogen phosphate aqueous solution, and removing water insoluble substances;

(2) the ammonium dihydrogen phosphate aqueous solution passes through an ion exchange device to remove nonferrous metals and impurity ions;

(3) evaporating and concentrating to obtain concentrated solution, wherein the mass fraction of ammonium dihydrogen phosphate in the concentrated solution is more than 35%;

(4) cooling and crystallizing the concentrated solution, performing centrifugal separation, drying the separated solid substance to form optical-grade ammonium dihydrogen phosphate, and mixing the separated liquid with the solution subjected to ion exchange in the step (2);

(5) uniformly mixing optical-grade ammonium dihydrogen phosphate and environment-friendly zinc oxide, and carrying out polymerization reaction to obtain a zinc metaphosphate intermediate;

(6) after clean pre-crushing the zinc metaphosphate intermediate, calcining to obtain zinc metaphosphate powder;

(7) and (3) cleanly crushing and cleanly mixing the zinc metaphosphate powder to obtain the finished product of the optical grade zinc metaphosphate powder.

2. The method for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (1), the solute mass fraction of the ammonium dihydrogen phosphate aqueous solution is 7% -17%.

3. The method for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (2), the ion exchange device is filled with cation exchange resin and anion exchange resin, said cation exchange resin comprises one or more of 001 × 4, 741, D001, iorreisin IR120 and iorreisin 35, and said anion exchange resin comprises one or more of D202, 201 × 4, 201 × 7, D406 and D407.

4. The method for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (2), the flow rate of the ammonium dihydrogen phosphate aqueous solution passing through the ion exchange apparatus is 1L/min-5L/min.

5. The method for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (3), the mass fraction of ammonium dihydrogen phosphate in the concentrate is 35-43%.

6. The process for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (4), the cooling crystallization temperature is 20 ℃ to 30 ℃ and the crystallization time is 1h to 4 h.

7. The method for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (4), the separated solid substance is dried by a high efficiency boiling dryer, the inlet air temperature of the high efficiency boiling dryer is 130-160 ℃, the tower body temperature is 115-145 ℃, the outlet air temperature is 90-110 ℃, and the drying time is 1.5-4 h.

8. The method for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (5), the molar ratio of environmentally friendly zinc oxide to optical grade ammonium dihydrogen phosphate is 1 (1.98-2.02).

9. The process for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (5), the polymerization reaction is carried out at a temperature of 450 ℃ to 550 ℃ for 4 to 8 hours.

10. The method for preparing optical grade zinc metaphosphate according to claim 1, wherein in step (6), the calcination temperature is 790 to 890 ℃ and the calcination time is 3 to 7 hours.

Technical Field

The invention relates to the field of fine inorganic phosphorus chemical industry, in particular to a preparation method of optical-grade zinc 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 zinc metaphosphate is mainly used for adding special optical glass, special protective glass, radiation-resistant glass material, phosphate glass, fluorophosphate glass and laser glass, and can slow the hardening speed of the glass during the forming process, reduce the crystallization tendency of the glass and improve the chemical stability and the mechanical strength of the glass. However, the existing zinc metaphosphate material is often doped with transition metals such as Fe, Co, Ni and the like, so that the metaphosphate glass generates strong absorption in the near ultraviolet to infrared regions, and the optical performance of the glass is influenced.

Disclosure of Invention

In view of the current state of the prior art, the technical problem to be solved by the present invention is to provide a method for preparing optical grade zinc metaphosphate, so that the prepared zinc metaphosphate meets the requirements 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 zinc metaphosphate, which comprises the following steps:

(1) preparing an ammonium dihydrogen phosphate aqueous solution, and removing water insoluble substances;

(2) the ammonium dihydrogen phosphate aqueous solution passes through an ion exchange device to remove nonferrous metals and impurity ions;

(3) evaporating and concentrating to obtain concentrated solution, wherein the mass fraction of ammonium dihydrogen phosphate in the concentrated solution is more than 35%;

(4) cooling and crystallizing the concentrated solution, performing centrifugal separation, drying the separated solid substance to form optical-grade ammonium dihydrogen phosphate, and mixing the separated liquid with the solution subjected to ion exchange in the step (2);

(5) uniformly mixing optical-grade ammonium dihydrogen phosphate and environment-friendly zinc oxide, and carrying out polymerization reaction to obtain a zinc metaphosphate intermediate;

(6) after clean pre-crushing the zinc metaphosphate intermediate, calcining to obtain zinc metaphosphate powder;

(7) and (3) cleanly crushing and cleanly mixing the zinc metaphosphate powder to obtain the finished product of the optical grade zinc metaphosphate powder.

It should be noted that the environmental grade zinc oxide adopted in the invention can be environmental grade 1 zinc oxide, and the environmental grade 1 zinc oxide includes Fe₂O₃Zinc oxide with the total content of 7 key impurities of Cu, Co, Cr, Mn, Ni and Pb not more than 5ppm, wherein the total content of Co, Cr, Mn, Ni and Pb not more than 2ppm, the content of Cu not more than 0.2ppm and the content of Fe₂O₃Content of not more than 2ppm, Cl^-The total content of sulfate radicals is not more than 100ppm, and the content of ZnO>99.7％。

Preferably, in the step (1), the solute mass fraction of the ammonium dihydrogen phosphate aqueous solution is 7-17%. More preferably, the concentration is 8 to 14%. And a precise cloth bag filter pressing mode is adopted when water insoluble substances are removed.

Preferably, in step (2), the ion exchange device is filled with cation exchange resin and anion exchange resin, the cation exchange resin comprises one or a combination of several of 001 × 4, 741, D001, iorreisin IR120 and iorreisin 35, and the anion exchange resin comprises one or a combination of several of D202, 201 × 4, 201 × 7, D406 and D407.

Preferably, the flow rate of the ammonium dihydrogen phosphate aqueous solution through the ion exchange unit is from 1L/min to 5L/min, and more preferably from 2L/min to 4L/min.

Preferably, in the step (3), the mass fraction of ammonium dihydrogen phosphate in the concentrated solution is 35% to 43%, and more preferably 36% to 40%.

Preferably, in the step (4), the cooling crystallization temperature is 20-30 ℃, and the crystallization time is 1-4 h. Further, the cooling crystallization temperature is 22-27 ℃, the crystallization time is 1-2.5 h, and circulating water cooling of a reaction kettle jacket or coil pipe is adopted.

Preferably, in the step (4), the separated solid matter is dried by a high-efficiency boiling dryer, wherein the air inlet temperature of the high-efficiency boiling dryer is 130-160 ℃, the tower body temperature is 115-145 ℃, the air outlet temperature is 90-110 ℃, the single feeding amount is 100-300 kg, and the drying time is 1.5-4 h. Furthermore, the air inlet temperature is 138-153 ℃, the tower body temperature is 122-138 ℃, the air outlet temperature is 95-105 ℃, the single feeding amount is 150-250 kg, and the drying time is 2-3 h. In order to ensure the product quality, the material contact part of the high-efficiency boiling dryer adopts a pure aluminum or pure titanium lining and the surface is highly polished, and the air inlet needs to be subjected to multi-stage purification treatment.

Preferably, in the step (5), the molar ratio of the environmental-friendly zinc oxide to the optical-grade ammonium dihydrogen phosphate is 1 (1.98-2.02), and the mixing time is 1-4 h. Furthermore, the mixing molar ratio of the environment-friendly zinc oxide to the optical ammonium dihydrogen phosphate is 1 (1.99-2.01), and the mixing time is 1.5-3 h. In order to mix the two materials fully and uniformly, a two-dimensional or three-dimensional mixing mode is adopted, and the contact part of the materials is subjected to plastic spraying treatment.

Preferably, in the step (5), the temperature for the polymerization reaction is 450 to 550 ℃ and the reaction time is 4 to 8 hours. Furthermore, the temperature is 480-530 ℃, and the calcining time is 5-7 h. An electric furnace calcining mode can be adopted to provide heat for the polymerization reaction, in order to ensure clean and pollution-free calcining, the material contact part in the calcining process adopts high-temperature-resistant carbon fibers, and the hearth is made of Monel alloy or Hastelloy materials.

In the process of preparing the zinc metaphosphate by the solid-solid calcination reaction, if a one-stage method-high temperature calcination is directly adopted, the phenomena that the materials are sintered and seriously adhered to a hearth can occur, so that the materials are difficult to strip and take out after the calcination reaction is finished. In order to solve the engineering problem, the intermediate temperature zone (450-550 ℃) is firstly adopted to calcine and deaminate to remove most of structural water and generate polymerization to generate a zinc metaphosphate intermediate, and high temperature resistant carbon fiber is used as a material contact medium to facilitate the taking out of the calcined material. However, the problem that it is difficult to completely dehydrate the zinc metaphosphate at this temperature range, and at most 95% of the structure water can be removed, requiring higher temperature and further calcination equipment to remove the final small amount of structure water.

Preferably, in the step (6), the calcining temperature is 790-890 ℃, the calcining time is 3-7 h, more preferably, the calcining temperature of the high-temperature electric furnace is 815-870 ℃, and the calcining time is 4-6 h. The calcining mode of the electric furnace can be adopted, and in order to ensure clean and pollution-free calcining, the high-temperature hearth is made of high-purity corundum or high-purity quartz.

Preferably, in the step (7), a ceramic pulverizer is adopted in the clean pulverizing process of the zinc metaphosphate crushed powder, a two-dimensional or three-dimensional mixing mode is adopted in the clean mixing process, and the mixing time is 1 h-4 h, more preferably 1.5 h-3 h. The material contact part adopts plastic spraying treatment.

The preparation method of the optical grade zinc metaphosphate in the technical scheme of the invention has the following beneficial effects: the industrial ammonium dihydrogen phosphate is purified by adopting an ion exchange method, and the optical grade zinc metaphosphate can be prepared by combining the environment-friendly zinc oxide and the optical grade ammonium dihydrogen phosphate solid-solid medium-high temperature two-stage clean calcination reaction, so that the optical grade zinc metaphosphate has strong adaptability to raw materials (the environment-friendly grade 1 zinc oxide is a highly mature raw material in the market), and the main technical indexes of the optical grade zinc metaphosphate can meet the requirements of the optical grade 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 zinc 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 preparation method of optical grade zinc metaphosphate in the technical scheme of the invention comprises the following steps:

(1) preparing ammonium dihydrogen phosphate aqueous solution, and removing water insoluble substances (namely, filter pressing);

(2) the ammonium dihydrogen phosphate aqueous solution passes through an ion exchange device (i.e. a cation exchange resin and an anion exchange resin in figure 1) to remove nonferrous metals and impurity ions;

(3) evaporating and concentrating (concentrating) to obtain a concentrated solution, wherein the mass fraction of ammonium dihydrogen phosphate in the concentrated solution is more than 35%;

(4) cooling and crystallizing the concentrated solution, performing centrifugal separation, drying (boiling and drying) the separated solid substance to form optical-grade ammonium dihydrogen phosphate, and mixing the separated liquid with the solution subjected to ion exchange in the step (2);

(5) optical-grade ammonium dihydrogen phosphate and environment-friendly zinc oxide are uniformly mixed and subjected to polymerization reaction (namely, middle-temperature clean electric furnace calcination) to obtain a zinc metaphosphate intermediate;

(6) after cleaning and pre-crushing the zinc metaphosphate intermediate, calcining (namely calcining in a high-temperature clean electric furnace) to obtain zinc metaphosphate powder;

(7) and (3) cleanly crushing and cleanly mixing the zinc metaphosphate powder to obtain the finished product of the optical grade zinc metaphosphate powder.