CN111392704A - A kind of preparation method of optical grade aluminum metaphosphate - Google Patents

Abstract

The technical scheme of the present invention provides a preparation method of optical grade aluminum metaphosphate, comprising the following steps: reacting aluminum hydroxide or aluminum oxide with phosphoric acid and water in a certain proportion to obtain a crude aluminum dihydrogen phosphate solution; adjusting the crude dihydrogen phosphate solution; The concentration of aluminum hydride solution is passed through ion exchange resin to remove non-ferrous metals and impurity ions; the solution after passing through ion exchange resin is evaporated and concentrated to more than 40%; the first clean calcination is carried out to remove Free water and structured water are used to obtain the intermediate powder of aluminum metaphosphate; the second clean calcination is carried out to obtain the finished product of optical grade aluminum metaphosphate. The preparation method of the technical solution of the present invention has strong adaptability to the raw material aluminum hydroxide or alumina, adopts the ion exchange method to remove impurities, indirect heating and clean spray calcination combined with high temperature electric furnace clean calcination, and the prepared aluminum metaphosphate has high purity. All indicators meet the requirements of optical glass and laser glass raw materials.

Description

A kind of preparation method of optical grade aluminum metaphosphate

technical field

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

Background technique

Metaphosphate is the most stable phosphate among dibasic phosphates, and is the basic raw material for making phosphate glass. Due to its excellent light transmission properties, high-purity metaphosphates can not only be used as an important raw material for laser glass in high-power lasers (such as the National Science Project ~ Shenguang Project), but also some advanced optical equipment such as camera lenses, high-definition cameras, intelligent It is an important raw material for mobile phone lens and mobile phone panel substrate. Due to the presence of transition metals Fe, Co, Ni, etc., the metaphosphate glass will have strong absorption in the near-ultraviolet to infrared region, which will affect the optical properties of the glass. Therefore, the preparation of high-purity metaphosphate raw materials has become the key to the manufacture of high-performance laser glass.

Although my country is already a big producer of phosphorus chemical products, the development of high-added and fine phosphorus chemical products is lagging behind and lacks competitiveness in the international market. In view of the technical blockade imposed on us by international counterparts, we can only improve the economic benefits of the enterprise by innovating independently, strengthening the in-depth development of fine phosphorus chemical products, improving the high-tech content of products, and increasing the added value of products.

Patent CN201810111408.4 discloses a method of using electronic grade phosphoric acid and aluminum source (high-purity aluminum hydroxide) to obtain acid aluminum phosphate powder through intermediate acid aluminum phosphate monohydrate and hygroscopic weathering, and then calcining to obtain high-purity aluminum metaphosphate. The whole process of the method must use high-purity raw materials, and there is no chemical purification process. The method has significant raw material limitations, complicated operation steps, and it is difficult to achieve a relatively high level of product purity (for example, the total amount of transition metal impurities is less than 2ppm).

SUMMARY OF THE INVENTION

In view of the current situation of the above-mentioned prior art, the technical problem to be solved in the present invention is to provide a method for preparing optical grade aluminum metaphosphate, and the main indicators of the prepared aluminum metaphosphate can meet the requirements for manufacturing optical glass and laser glass. Require.

In order to solve the above-mentioned technical problems, the technical solution of the present invention provides a preparation method of optical grade aluminum metaphosphate, comprising the following steps:

1) reacting aluminum hydroxide or aluminum oxide with phosphoric acid and water in a certain proportion to obtain a thick aluminum dihydrogen phosphate solution;

2) adjust the concentration of the crude aluminum dihydrogen phosphate solution to pass through the ion exchange resin to remove non-ferrous metals and impurity ions;

3) Evaporating and concentrating the solution after passing through the ion exchange resin to more than 40%;

4) carry out clean calcination for the first time to remove free water and structured water to obtain aluminum metaphosphate intermediate powder;

5) Carry out the second clean calcination to obtain the finished product of optical grade aluminum metaphosphate.

Preferably, in step 1), the molar ratio of aluminum hydroxide or alumina to the phosphoric acid is 1:(5.9～6.1), the mass ratio of phosphoric acid to water is 1:(0.6～1.5), and the reaction temperature is 105° C. ~125°C. More preferably, the molar ratio of aluminum hydroxide or alumina to the phosphoric acid is 1:(5.95～6.05), the mass ratio of phosphoric acid and water is 1:(0.6～0.9), and the reaction temperature is 110℃～120℃ .

Preferably, the concentration of the crude aluminum dihydrogen phosphate solution is adjusted to be 9% to 18%, and the flow rate through the ion exchange resin is 1L/min to 5L/min. Further preferably, the concentration of the crude aluminum dihydrogen phosphate solution is adjusted to be 9% to 14%, and the flow rate through the ion exchange resin is 2L/min to 4L/min.

Preferably, the ion exchange resin includes cation exchange resin and anion exchange resin, the ion exchange resin includes cation exchange resin and anion exchange resin, and the cation exchange resin includes D401, D402, D403, D405, IONRESIN 35, IONRESIN 1600 , one or more combinations of IONRESIN 252, and the anion exchange resin includes one or more combinations of IONRESIN IRA400, IONRESIN IRA402, IONRESIN IRA900, IONRESIN IRA456, and D407.

Preferably, in step 3), the concentration is 40% to 50%. More preferably, it is concentrated to 42-47%.

Preferably, the concentrated aluminum dihydrogen phosphate solution enters the spray calcination tower at a flow rate of 6L/min～15L/min for the first clean calcination, wherein the inlet air temperature is 700°C～800°C, and the temperature of the upper section of the tower body is 680°C ℃～750℃, the temperature in the middle section of the tower body is 650℃～720℃, the temperature in the lower section of the tower body is 620℃～700℃, and the air outlet temperature is 400℃～500℃.

Further, the concentrated aluminum dihydrogen phosphate solution enters the spray calcining tower at a flow rate of 9L/min～12L/min for the first clean calcination, wherein the inlet air temperature is 680 ℃～730 ℃, and the temperature of the upper section of the tower body is 650℃～700℃, the temperature in the middle section of the tower body is 630℃～680℃, the temperature in the lower section of the tower body is 600℃～630℃, and the air outlet temperature is 380℃～430℃. In order to ensure product quality, the material contact part of the calcining tower is lined with high-purity alumina, and the nozzle is made of titanium-palladium alloy (which can prevent the pollution of the nozzle to the product during the spray calcination process). The heating method adopts indirect heating, and the high-temperature exhaust gas passes through the heat exchanger The heat exchange heating spray calcination tower enters the air, the whole system has high thermal efficiency and low energy consumption.

In the process of spray calcination, in order to ensure that the material is not polluted, it is necessary to ensure clean calcination, and only indirect heating can be used. The temperature of the tower body can only reach 700℃～740℃), in the condition of instantaneous calcination and dehydration, it is difficult to completely dehydrate the calcination of aluminum metaphosphate in this temperature range, and at most 98% of diphosphate can be removed. Hydro-aluminum structural water requires higher persistent temperature and further calcination equipment to remove the final trace amount of structural water. Therefore, the present invention adopts the secondary calcination method, and conducts the secondary clean calcination in an electric furnace, the calcination temperature of the electric furnace is 750°C to 850°C, and the calcination time is 4h to 10h.

Further, in step e, the calcination temperature of the electric furnace is 780°C to 840°C, and the calcination time is 6h to 9h. The furnace is lined with high-purity alumina or high-purity quartz material.

The preparation method of optical grade aluminum metaphosphate of the technical scheme of the present invention has the following beneficial effects: strong adaptability to raw material aluminum hydroxide, aluminum oxide and phosphoric acid, ion exchange method is used to remove impurities, indirect heating and clean spray calcination combined with high temperature electric furnace clean calcination In this way, the total amount of transition metal impurities can be controlled below 2ppm, and ultra-purity aluminum metaphosphate can be produced. All indicators meet the requirements of optical glass and laser glass raw materials.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only for the present invention. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the flow chart of the preparation method of the optical grade aluminum metaphosphate of the technical scheme of the present invention.

Detailed ways

The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings, so as to fully understand the purpose, characteristics and effects of the present invention.

As shown in Figure 1, the preparation method of the optical grade aluminum metaphosphate of the technical scheme of the present invention comprises the following steps:

1) reacting aluminum hydroxide or aluminum oxide with phosphoric acid and water in a certain proportion (that is, the heating stepwise reaction in Fig. 1) to obtain a thick aluminum dihydrogen phosphate solution;

2) adjust the concentration of the crude aluminum dihydrogen phosphate solution to pass through the ion exchange resin to remove non-ferrous metals and impurity ions;

3) Evaporating and concentrating the solution after passing through the ion exchange resin to more than 40%;

4) carry out clean calcination for the first time to remove free water and structured water to obtain aluminum metaphosphate intermediate powder;

5) Carry out the second clean calcination to obtain the finished product of optical grade aluminum metaphosphate.

Example 1

The preparation method of the optical grade aluminum metaphosphate of the embodiment of the present invention comprises the following steps:

1) 100kg content is that the alumina of 97.5% is gradually added in the dilute phosphoric acid that is blended by 664.1kg 85% industrial phosphoric acid and 464.9kg water, and the control reaction temperature is 110 ℃～115 ℃, obtains thick aluminum dihydrogen phosphate solution ;

2) Adjust the concentration of the crude aluminum dihydrogen phosphate solution to 12%, and pass through a group of cation exchange resins filled with D403, D405, IONRESIN 35 type cation exchange resins and specially selected IONRESIN IRA402, IONRESIN IRA900 type anion exchange resins at a flow rate of 4L/min. Composite ion exchange device to remove non-ferrous metals such as Fe, Mn, Pb, Cr, Cu, Ni, Co, and impurities such as ^Cl- and sulfate;

3) Evaporating and concentrating the solution after the ion exchange resin to 45%;

4) The concentrated aluminum dihydrogen phosphate solution is controlled by an industrial peristaltic pump, and enters the spray calcination tower at a flow rate of 10L/min. ℃, the temperature in the middle section of the tower body is 630 ℃～660 ℃, the temperature in the lower section of the tower body is 600 ℃～620 ℃, the air outlet temperature is 390 ℃～420 ℃, obtain 515kg of aluminum metaphosphate intermediate powder;

5) The aluminum metaphosphate intermediate powder was calcined in an electric furnace lined with high-purity corundum material at 800° C. for 6 hours to obtain 492 kg of optical grade aluminum metaphosphate products, with a comprehensive yield of 97.5%.

Example 2

The preparation method of the optical grade aluminum metaphosphate of the embodiment of the present invention comprises the following steps:

1) 120kg content is that 96% alumina is gradually added into the dilute phosphoric acid that is blended by 780kg 85% industrial phosphoric acid and 546kg water, and the control reaction temperature is 110 ℃～115 ℃, obtains thick aluminum dihydrogen phosphate solution;

2) Adjust the concentration of the crude aluminum dihydrogen phosphate solution to 10%, and pass through a group of D401 and D402 cation exchange resins modified with aluminum salts and specially selected IONRESIN IRA456 and D407 anion exchange resins at a flow rate of 5L/min. The composite ion exchange device is used to remove non-ferrous metals such as Fe, Mn, Pb, Cr, Cu, Ni, Co and impurities such as ^Cl- and sulfate;

3) Evaporating and concentrating the solution after the ion exchange resin to 42%;

4) The concentrated aluminum dihydrogen phosphate solution is controlled by an industrial peristaltic pump, and enters the spray calcination tower with a flow rate of 12L/min. ℃, the temperature in the middle section of the tower body is 640 ℃～665 ℃, the temperature in the lower section of the tower body is 610 ℃～625 ℃, the air outlet temperature is 400 ℃～420 ℃, obtain 602kg of aluminum metaphosphate intermediate powder;

5) The aluminum metaphosphate intermediate powder was calcined at 820° C. for 5 hours in an electric furnace lined with high-purity corundum material to obtain 572 kg of optical grade aluminum metaphosphate products, with a comprehensive yield of 95.9%.

Example 3

The preparation method of the optical grade aluminum metaphosphate of the embodiment of the present invention comprises the following steps:

1) 140kg content is that the alumina of 97% is gradually added in the dilute phosphoric acid that is blended by 928.2kg 85% industrial phosphoric acid and 649.8kg water, and the control reaction temperature is 112 ℃～116 ℃, obtains thick aluminum dihydrogen phosphate solution ;

2) Adjust the concentration of the crude aluminum dihydrogen phosphate solution to 11%, and pass through a group of D402, D403, D405 cation exchange resins modified with aluminum salts and specially selected IONRESIN IRA400 and IONRESINIRA402 types at a flow rate of 4.5L/min. Composite ion exchange device of anion exchange resin to remove non-ferrous metals such as Fe, Mn, Pb, Cr, Cu, Ni, Co and impurities such as ^Cl- and sulfate;

3) Evaporating and concentrating the solution after the ion exchange resin to 46%;

4) The concentrated aluminum dihydrogen phosphate solution is controlled by an industrial peristaltic pump, and enters the spray calcination tower at a flow rate of 11 L/min. ℃, the temperature in the middle section of the tower body is 650 ℃～670 ℃, the temperature in the lower section of the tower body is 620 ℃～640 ℃, the air outlet temperature is 405 ℃～420 ℃, obtains 710kg of aluminum metaphosphate intermediate powder;

5) The aluminum metaphosphate intermediate powder was calcined at 790° C. for 7 hours in an electric furnace lined with high-purity corundum material to obtain 668 kg of optical grade aluminum metaphosphate products, with a comprehensive yield of 95.1%.

Example 4

The preparation method of the optical grade aluminum metaphosphate of the embodiment of the present invention comprises the following steps:

1) 200kg of alumina with a content of 96% is gradually added to the dilute phosphoric acid that is blended by 1308.8kg 85% of industrial phosphoric acid and 916.2kg of water, and the controlled reaction temperature is 110°C to 115°C to obtain a crude aluminum dihydrogen phosphate solution ;

2) Adjust the concentration of the crude aluminum dihydrogen phosphate solution to 12%, and pass through a group of D405, IONRESIN 1600, IONRESIN 252 cation exchange resins and specially selected IONRESINIRA400, IONRESIN IRA402 filled with aluminum salts at a flow rate of 4L/min , IONRESIN IRA900 type anion exchange resin composite ion exchange device to remove Fe, Mn, Pb, Cr, Cu, Ni, Co and other non-ferrous metals and ^Cl- , sulfate and other impurities;

3) Evaporating and concentrating the solution after the ion exchange resin to 45%;

4) The concentrated aluminum dihydrogen phosphate solution is controlled by an industrial peristaltic pump, and enters the spray calcination tower with a flow rate of 12L/min. ℃, the temperature in the middle section of the tower body is 650 ℃～670 ℃, the temperature in the lower section of the tower body is 615 ℃～630 ℃, the air outlet temperature is 400 ℃～420 ℃, obtain 989kg of aluminum metaphosphate intermediate powder;

5) The aluminum metaphosphate intermediate powder was calcined at 840° C. for 5 hours in an electric furnace lined with high-purity corundum material to obtain 949 kg of optical grade aluminum metaphosphate products, with a comprehensive yield of 95.5%.

Example 5

The preparation method of the optical grade aluminum metaphosphate of the embodiment of the present invention comprises the following steps:

1) 170kg of alumina with a content of 98% is gradually added to the dilute phosphoric acid blended by 1127.6kg of 85% industrial phosphoric acid and 789.4kg of water, and in 1917kg of industrial phosphoric acid with a content of 50%, the control reaction temperature is 113 ℃～ 118 ° C to obtain crude aluminum dihydrogen phosphate solution;

2) Adjust the concentration of the crude aluminum dihydrogen phosphate solution to 12.5%, pass through a group of IONRESIN 35, IONRESIN 1600 cation exchange resins modified with aluminum salts and specially selected IONRESIN IRA900, IONRESIN IRA456 at a flow rate of 4.2L/min Type anion exchange resin composite ion exchange device to remove Fe, Mn, Pb, Cr, Cu, Ni, Co and other non-ferrous metals and ^Cl- , sulfate and other impurities;

3) Evaporating and concentrating the solution after the ion exchange resin to 44%;

4) The concentrated aluminum dihydrogen phosphate solution is controlled by an industrial peristaltic pump, and enters the spray calcination tower with a flow rate of 11 L/min. ℃, the temperature in the middle section of the tower body is 660 ℃～680 ℃, the temperature in the lower section of the tower body is 630 ℃～650 ℃, the air outlet temperature is 410 ℃～430 ℃, obtain 854kg of aluminum metaphosphate intermediate powder;

5) The aluminum metaphosphate intermediate powder was calcined in an electric furnace lined with high-purity corundum material at 850° C. for 4.5 hours to obtain 827 kg of optical grade aluminum metaphosphate products, with a comprehensive yield of 95.9%.

The aluminum metaphosphate samples prepared in Examples 1 to 5 were analyzed, and the results were shown in Table 1:

Table 1 Analysis of aluminum metaphosphate samples

As can be seen from Table 1, in the aluminum metaphosphates prepared in Examples 1-5, the total content of 10 key impurity indexes such as Fe ₂ O ₃ , Cu, Co, Cr, Mn, Ni, Pb, etc. does not exceed 5ppm, of which Co The total content of , Cr, Mn, Ni, Pb, etc. should not exceed 1ppm, the Cu content should not exceed 0.2ppm, the Fe ₂ O ₃ content should not exceed 2 ppm, the total content of Cl ^- and sulfate should not exceed 100 ppm, and the Al ₂ O ₃ content should not exceed 19±0.5 %, P ₂ O ₅ content 81±0.5%.

To sum up, the aluminum metaphosphate prepared by the present invention has high main content, very low impurity content, stable quality and uniform particle size, and each index meets the index requirements of laser glass and optical glass raw materials, and the optical grade metaphosphoric acid of the present invention is The preparation method of aluminum is efficient and simple, and the production cost is low.

The specific embodiments of the present invention are described above in detail, and it should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the prior art according to the concept of the present invention shall fall within the protection scope determined by the claims.

Claims (9)

1. a preparation method of optical grade aluminum metaphosphate, is characterized in that, comprises the steps: 1) reacting aluminum hydroxide or aluminum oxide with phosphoric acid and water in a certain proportion to obtain a thick aluminum dihydrogen phosphate solution; 2) adjust the concentration of the crude aluminum dihydrogen phosphate solution to pass through the ion exchange resin to remove non-ferrous metals and impurity ions; 3) Evaporating and concentrating the solution after passing through the ion exchange resin to more than 40%; 4) carry out clean calcination for the first time to remove free water and structured water to obtain aluminum metaphosphate intermediate powder; 5) Carry out the second clean calcination to obtain the finished product of optical grade aluminum metaphosphate. 2. the preparation method of optical grade aluminum metaphosphate as claimed in claim 1 is characterized in that, in step 1), the mol ratio of aluminum hydroxide or aluminum oxide and described phosphoric acid is 1:(5.9～6.1), phosphoric acid The mass ratio to water is 1:(0.6～1.5), and the reaction temperature is 105℃～125℃. 3. the preparation method of optical grade aluminium metaphosphate as claimed in claim 1 is characterized in that, the concentration that regulates thick aluminium dihydrogen phosphate solution is 9%～18%, and the flow velocity through ion exchange resin is 1L/min～5L /min. 4. The preparation method of optical grade aluminum metaphosphate as claimed in claim 1, is characterized in that, described ion exchange resin comprises cation exchange resin and anion exchange resin, and described cation exchange resin comprises D401, D402, D403, D405, One or more combinations of IONRESIN 35, IONRESIN 1600, and IONRESIN 252, and the anion exchange resin includes one or more combinations of IONRESIN IRA400, IONRESIN IRA402, IONRESIN IRA900, IONRESIN IRA456, and D407. 5 . The preparation method of optical grade aluminum metaphosphate according to claim 1 , wherein, in step 3), the concentration is increased to 40% to 50%. 6 . 6. the preparation method of optical grade aluminium metaphosphate as claimed in claim 1 is characterized in that, the aluminium dihydrogen phosphate solution after the concentration enters spray calcination tower with the flow velocity of 6L/min～15L/min and carries out cleaning for the first time Calcination, wherein the inlet air temperature is 700 ℃ ~ 800 ℃, the temperature of the upper section of the tower body is 680 ℃ ~ 750 ℃, the temperature of the middle section of the tower body is 650 ℃ ~ 720 ℃, the temperature of the lower section of the tower body is 620 ℃ ~ 700 ℃, the air outlet temperature is 400℃～500℃. 7. the preparation method of optical grade aluminum metaphosphate as claimed in claim 6, is characterized in that, material contact part in described spray calcination tower adopts high-purity alumina lining, and nozzle adopts titanium palladium alloy to manufacture, and heating mode adopts indirect heating. 8 . The preparation method of optical grade aluminum metaphosphate according to claim 1 , wherein the second clean calcination is carried out by using an electric furnace, the calcination temperature of the electric furnace is 750° C. to 850° C., and the calcination time is 4 h to 10 h. 9 . 9 . The preparation method of optical grade aluminum metaphosphate according to claim 8 , wherein the furnace of the electric furnace adopts high-purity alumina or high-purity quartz material as the inner lining. 10 .

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