CN101182413A - A kind of manufacturing method of rare earth aluminate matrix fluorescent powder - Google Patents

Abstract

A method for manufacturing aluminate-based fluorescent powder, including seven steps of raw material pretreatment, wet mixing, high-temperature air synthesis, crushing and classification, high-temperature reduction, secondary classification, and surface coating, and finally obtains a surface Finished aluminate phosphor coated with MgO film. The method of the present invention fully combines the advantages of the wet chemical method, the solid phase reaction method and the modern jet milling and classification technology, and improves the reactivity of the synthetic raw material through the pretreatment of the synthetic raw material and the wet mixing process. The method and airflow classification technology can effectively control the central particle size and distribution of the phosphor, and finally can produce phosphor products with high luminous efficiency and fine particle size distribution, which have significant application prospects.

Description

A kind of manufacturing method of rare earth aluminate matrix fluorescent powder

technical field

The invention relates to a method for manufacturing an aluminate matrix phosphor, in particular to a method for manufacturing a phosphor for a plasma panel display (PDP) and a phosphor for a light-emitting diode, and belongs to the field of luminescent materials.

Background technique

The color plasma display panel (Plasma Display Panel, PDP) uses the vacuum ultraviolet (VUV) generated by the discharge of the inert mixed gas to excite the phosphor to achieve the purpose of imaging. The excitation wavelength range of phosphor powder for PDP is 100-200nm, and the main excitation bands are around 147nm and 172nm.

The composition of the red, green and blue tricolor phosphors most commonly used in the PDP field is: red powder (Y ₂ O ₃ :Eu ³⁺ , (Y,Gd)BO ₃ :Eu ³⁺ ), green powder (ZnSiO ₄ :Mn ²⁺ , BaAl ₁₂ O ₁₉ :Mn ²⁺ ), blue powder (BaMgAl ₁₀ O ₁₇ :Eu ²⁺ ), these phosphors have been widely used in plasma displays due to their good luminous efficiency and chemical stability. field.

At present, aluminate-based green powder (Ba _1-z , Sr _x , Mg _y )O·aAl ₂ O ₃ :Mn _z (where 0<x≤1, 0<y≤1.5, 0.01<z≤0.5, a is an integer between 1 and 23) and aluminate matrix blue powder (Ba _1-m , Sr _n , Mg _p )0·bAl ₂ O ₃ :Eu _m (wherein 0≤n≤1, 0<p<2 , 0.005<m≤0.2, b is an integer between 1 and 23) due to its comprehensive advantages in luminous efficiency, color purity and chemical stability, it has become the first choice for PDP phosphors. Therefore, the development of blue powder or green powder for this kind of aluminate matrix system has always been the focus of the research community.

In the past two years, in order to meet the upcoming digital and high-definition display requirements, the resolution of the PDP display screen has gradually developed from the original VGA level (852×480) to XGA or WXGA level (1280×720) or even higher. Corresponding to this, the barrier spacing in the PDP panel will be further reduced, thus putting forward higher requirements for the particle size index of the phosphor, that is, the phosphor must not only have a higher luminous efficiency, but also have a finer particle size. Central particle size and more concentrated particle size distribution characteristics. Because of this, fine particle size and high luminous performance have always been the technical bottleneck restricting high-quality PDP phosphors, and are considered to be a key indicator to measure the quality of PDP phosphors. Therefore, how to obtain high light efficiency and fine particle size And its narrow distribution manufacturing technology has become the core technology of PDP phosphor.

At present, aluminate-based phosphors for foreign commercial PDPs are still mostly prepared by high-temperature solid-state reaction methods. The high-temperature solid-phase method has the advantages of simple process flow and stable product quality. However, in order to ensure that the phase is synthesized at a lower temperature during the synthesis process, it is generally necessary to add a flux to achieve the above purpose. However, this will lead to more serious point sintering of the powder, and serious adhesion between the particles. It must be crushed mechanically to reduce the particle size of the powder to meet the actual use requirements. Therefore, the development of aluminate-based phosphors with high luminous efficiency and fine powder particle size has always been the focus of researchers.

In order to achieve this goal, people have successively carried out a large number of researches and attempts on wet chemical methods such as coprecipitation method, sol-gel method, spray pyrolysis and combustion method. However, due to the shortcomings of these wet chemical methods in process control, quality assurance, cost and other aspects, it is still difficult to apply to actual production.

Contents of the invention

The present invention aims to solve the problems existing in the above-mentioned prior art, and provides a method for manufacturing aluminate-based phosphors to obtain high-brightness, fine-grained aluminate phosphors for PDPs to meet the requirements of future high-definition phosphors. PDP displays have higher requirements.

The present invention rationally combines the respective advantages of the solid-phase method and the wet chemical method, and the prepared phosphor not only has higher luminous efficiency, but also can obtain finer phosphor particles without loss of crystallinity. The particle size and narrower distribution width can better meet the actual use requirements.

The aluminate-based fluorescent powder of the present invention is aluminate-based green powder (Ba _1-z , Sr _x , Mg _y )O·aAl ₂ O ₃ :Mn _z (wherein 0<x≤1, 0<y≤ 1.5, 0.01<z≤0.5, a is an integer between 1 and 23) and aluminate matrix blue powder (Ba _1-m , Sr _n , Mg _p )O·bAl ₂ O ₃ :Eu _m (wherein 0 ≤n≤1, 0<p<2, 0.005≤m≤0.2, b is an integer between 1 and 23), the manufacturing method includes the following steps:

(1) Raw material pretreatment

According to the chemical structure formula of aluminate-based phosphors, disperse various raw materials for the synthesis of aluminate phosphors into an acid solution with a molar concentration of 0.1M-2.0M, adjust the pH value to 2-5, stir and stand for soaking Centrifuge and dehydrate, then wash until the supernatant is neutral;

(2) wet mixing

Mix at least one compound among NH ₄ F and HBO ₃ with BaF ₂ in any weight ratio as a reaction accelerator, dissolve it in the phosphor powder raw material suspension that has been washed to neutral, stir, let it stand, and then dry it; the above reaction The dosage of the accelerator is 0.5-10% of the weight of the phosphor raw material;

(3) Primary high temperature air synthesis

Heat the dried powder to 1300-1600°C in an air atmosphere, keep it warm for 2-12 hours, and cool it to room temperature with the furnace;

(4) Primary crushing and grading

The synthesized powder blocks are crushed and classified into primary fired powders with a central particle diameter of D50≤3.5μm, D10≥1μm, and D90≤7μm.

(5) Secondary high temperature reduction

Put the powder obtained by one high-temperature air synthesis into a high-temperature hydrogen furnace, heat it to 1200-1550°C, keep it warm for 2-12 hours, and cool it to room temperature with the furnace to get the phosphor;

(6) Secondary classification

The phosphor powder obtained by the secondary reduction is classified again to obtain phosphors with a central particle diameter of D50 ≤ 3.2 μm, D10 ≥ 1 μm, and D90 ≤ 6 μm;

(7) Surface coating

Wash the phosphor powder after secondary classification until the supernatant is neutral, take 0.5-20% MgCl ₂ of the phosphor powder weight, and prepare phosphor suspension with a concentration of 0.2-10% together with the phosphor powder, and disperse it by ultrasonic 1. After keeping warm in a water bath, stir to form a phosphor suspension; add NH ₃ ·H ₂ O solution with a molar concentration of 0.25-2M into the phosphor suspension in a dropwise manner, and adjust the pH value of the solution to a range of 8-10 before ending the dripping. Add, continue to keep warm and stir, then centrifuge, wash with water until neutral, then dehydrate and dry, heat to 200-400°C in the air, keep warm for 30-120min, and cool with the furnace to get the final surface coated with MgO film aluminate phosphor finished product.

The acid solution described in the aforementioned step (1) is HNO ₃ or HCl solution, the stirring time is 30-240 min, the soaking time is 6-48 h, and the distilled water or deionized water is used to wash until the supernatant is neutral.

After the stirring time in the aforementioned step (2) is 30-300 min, the standing time is 1-12 h, and the drying temperature is 80-200° C. The weight of the reaction accelerator in step (2) is preferably 1-5% of the total weight of the phosphor raw material.

The primary crushing and grading of the aforementioned step (4) is to firstly add the synthesized powder to a jaw crusher for primary crushing, and then add the powder obtained by crushing the jaw crusher into a corundum roller crushing machine for further crushing to powder state, and finally the powder obtained by the roll crushing is put into the jet mill classifier for classification. Among them, the jaw crusher is preferably a jaw crusher with a corundum plate as the inner lining. The central particle size of the primary fired powder obtained by crushing and classifying in step (4) is preferably such that D50 is ≤3.2 μm, D10 ≥ 1 μm, and D90 ≤ 6 μm.

The secondary classification described in the aforementioned step (6) is carried out using an air classifier. Phosphor powder with central particle diameter D50≤3.0μm, D10≥1μm and D90≤6μm is obtained.

In the aforementioned step (7), use 40-100°C deionized water or distilled water to wash the classified fluorescent powder until the supernatant is neutral; the ultrasonic dispersion time is 10-30 minutes; the temperature of the water bath is 20-60°C, and the water bath The time is 30-120min; use a high-speed mixer to stir the phosphor suspension at a speed of 100-800rpm/min; the dropping rate of the NH ₃ ·H ₂ O solution is 2-50ml/min, continue to keep warm and stir after the speed is dropped The time is 0.5-6h; after centrifugation, wash with deionized water until neutral, then dehydrate with absolute ethanol, and dry at 80-150°C.

In the step (7), MgCl ₂ preferably accounts for 2.5-7.5% by weight of the phosphor powder.

In step (7), NH ₃ ·H ₂ O is added dropwise to adjust the pH value of the solution to preferably 8-9.

The present invention has the following advantages:

(1) Using HNO ₃ or HCl aqueous solution to pre-treat the raw materials of synthetic phosphors under acidic conditions, the Al ₂ O ₃ , BaCO ₃ , MgO, Eu ₂ O ₃ and MnCO used in the synthesis of aluminate phosphors can be The surface functional group types and surface activity of ₃ and other raw materials are adjusted, which will play a very beneficial role in effectively reducing the synthesis temperature in the subsequent high-temperature synthesis process.

(2) Water-soluble compounds such as NH ₄ F or H ₃ BO ₃ are specially used as reaction accelerators. After NH ₄ F and H ₃ BO ₃ are dissolved, the F ^- ions or BO ₃ ^3- ions generated by ionization can be used in the already The powder surface of the raw material for phosphor powder synthesis with peracid pretreatment forms a uniform adsorption, thereby greatly reducing the amount of accelerator used, avoiding severe sintering or adhesion of the synthesized powder, and is conducive to obtaining phosphor powder with fine particle size.

(3) The primary synthesis powder and the secondary reduction powder of the phosphor are crushed and classified by an airflow classifier twice. On the one hand, because the working principle of the airflow crushing and classifying machine is to rely on the high-speed collision and crushing between the powders to achieve the purpose of reducing the particle size, it can effectively avoid or reduce the surface damage caused by the traditional ball mill mainly grinding. Crystallinity loss. On the other hand, through the airflow classification, it is also possible to screen out most of the powder that is too fine or too coarse, so as to effectively ensure the central particle size and particle size distribution of the phosphor powder, which is very important for the coating and application of high-definition plasma displays. A showing request would be very beneficial.

(4) By coating the surface of the fluorescent powder with MgO, the thermal degradation caused by the coating process of the fluorescent powder can be effectively reduced. The reason is that the MgO film on the surface of the phosphor can effectively block the intrusion of external oxygen [O] during burning, thereby preventing the excitation center Mn ²⁺ (or Eu ²⁺ ) in the phosphor from being oxidized to Mn ³⁺ (or Eu ^{3 +} ); in the PDP working state, the envelope can also alleviate the work deterioration caused by high-energy ion bombardment and vacuum ultraviolet (VUV) irradiation, and prolong the working life of the PDP.

(6) Since MgO has a high secondary electron emission coefficient, as a coating material, it can also play a role in reducing the ignition voltage of the phosphor, thereby reducing energy consumption.

(7) The method effectively combines the advantages of high-temperature solid-phase method, ultra-fine powder crushing and classification technology, and powder surface modification technology, and the process is simple and easy to control. Compared with wet methods such as co-precipitation, sol-gel, spray pyrolysis, etc., the manufacturing method provided by the present invention has more advantages in cost control and production control, and is easy to realize large-scale production.

Detailed ways

Example 1

1) Raw material pretreatment

According to the chemical structural formula of Ba _0.85 MgAl ₁₀ O ₁₇ :Eu _0.06 , 13.98 g of BaCO ₃ , 3.33 g of MgO, 41.67 g of Al ₂ O ₃ , and 0.88 g of Eu ₂ O ₃ were weighed. Place in _HNO3 aqueous solution with a molar concentration of 0.2M, adjust the pH value to 2, stir for 30 minutes, let stand for soaking for 6 hours, centrifuge and dehydrate, and then wash with distilled water (or deionized water) until the supernatant is neutral.

2) wet mixing

Weigh 0.9 g of NH ₄ F (0.5-10%) and dissolve it in the phosphor powder raw material suspension that has been washed to neutral, stir for 50 min, let stand for 1 h, and dry at 80°C.

3) One-time high-temperature air synthesis

Put it in a high-temperature furnace under an air atmosphere, heat it to 1300 ° C, keep it warm for 6 hours, and cool it to room temperature with the furnace;

4) One-time jet milling and grading

Put the calcined powder into the jaw crusher with corundum plate as the inner liner for primary crushing, and then put the powder obtained by the jaw crusher into the corundum roller crusher for further crushing to powder state. Finally, the powder obtained by roller crushing is added to the jet mill classifier to obtain a primary firing powder with a central particle size (D50) ≤ 3.5 μm, D10 ≥ 1 μm, and D90 ≤ 7 μm.

5) Secondary high temperature reduction

Put the primary synthetic powder obtained by classification into a crucible, place it in a high-temperature hydrogen furnace, heat it to 1350°C, keep it warm for 3 hours, and cool it to room temperature with the furnace to get the fired phosphor.

(6) Secondary classification

The phosphor powder obtained by the secondary reduction will be classified again by an airflow classifier to obtain a phosphor powder with a central particle diameter (D50) ≤ 3.2 μm, D10 ≥ 1 μm, and D90 ≤ 6 μm.

(7) Surface coating

Wash the graded fluorescent powder with deionized water (or distilled water) with deionized water at 60°C until the supernatant is neutral, then weigh 0.29g (0.5-20%) of MgCl ₂ and prepare it with the fluorescent powder at a concentration of 0.5 % fluorescent powder suspension, ultrasonically dispersed for 10min, kept at 50°C in a water bath, while stirring the phosphor suspension at a speed of 100rpm/min, while stirring the phosphor suspension with a molar concentration of 0.25M NH ₃ ·H ₂ O solution at a rate of 3ml/min Add the phosphor suspension into the phosphor suspension at a dropping speed, adjust the pH value of the solution to 8, stop the dripping of the ammonia solution, continue to keep warm and stir for 1 hour, centrifuge, wash with deionized water until neutral, and then dehydrate with absolute ethanol, 80 ℃ drying, heating to 200 ℃ in the air, holding the temperature for 30min, and cooling with the furnace to obtain the finished product of aluminate blue phosphor coated with MgO film on the surface.

Example 2

Treat raw materials according to the same chemical ratio and pretreatment process as in Example 1, take 0.15g of NH ₄ F and 0.28g of BaF ₂ , disperse them in the phosphor suspension, stir for 30min, let stand for 6h, and dry at 100°C Put it in a high-temperature furnace, hold it at 1500°C for 4 hours, and cool it to room temperature with the furnace; put the fired powder into a jaw crusher with a corundum plate as the inner liner for primary crushing, and then crush the jaw crusher to obtain The powder is added to a corundum roller crusher for further crushing to a powder state. Finally, the powder obtained by roller crushing is fed into the jet mill classifier to obtain a primary firing powder with a central particle size (D50) ≤ 3.5 μm, D10 ≥ 1 μm, and D90 ≤ 7 μm. Put the primary synthetic powder obtained by classification into a crucible, place it in a high-temperature hydrogen furnace, keep it warm at 1450°C for 6 hours, and then cool it to room temperature with the furnace and leave the furnace. The phosphor powder obtained by the secondary reduction will be classified again by an airflow classifier to obtain Phosphor powder with a central particle size (D50) ≤ 3.2 μm, D10 ≥ 1 μm, and D90 ≤ 6 μm.

Wash the graded fluorescent powder with deionized water (or distilled water) with deionized water at 80°C until the supernatant is neutral, then weigh 0.6g (0.5-20%) of MgCl ₂ and prepare it with the fluorescent powder at a concentration of 0.5 % phosphor suspension, ultrasonically disperse for 10min, keep warm in a water bath at 50°C, stir the phosphor suspension at a speed of 400rpm/min, and mix the NH ₃ ·H ₂ O solution with a molar concentration of 0.05M at 15ml/min Add the phosphor suspension into the phosphor suspension at a dropping speed, adjust the pH value of the solution to 9, stop the dripping of the ammonia solution, continue to keep warm and stir for 1 hour, centrifuge, wash with deionized water until neutral, and then dehydrate with absolute ethanol, 120 ℃ drying, heating to 300 ℃ in the air, holding the temperature for 30 minutes, and cooling with the furnace to obtain the final product of aluminate blue phosphor coated with MgO film on the surface.

Example 3

Treat raw materials according to the same chemical ratio and pretreatment process as in Example 1, take 1.2g of NH ₄ F and 2.5g of H ₃ BO ₃ , disperse them in the phosphor suspension, stir for 30 minutes, let stand for 12 hours, and bake at 100°C After drying, put it in a high-temperature furnace, keep it warm at 1550 ° C for 3 hours, and then cool it to room temperature with the furnace; put the fired powder into a jaw crusher with a corundum plate as the inner liner for primary crushing, and then crush the jaw crusher The obtained powder is added to a corundum roller crusher for further crushing to a powder state. Finally, the powder obtained by roller crushing is added to the jet mill classifier to obtain a primary firing powder with a central particle size (D50) ≤ 3.5 μm, D10 ≥ 1 μm, and D90 ≤ 7 μm. Put the primary synthetic powder obtained by classification into a crucible, place it in a high-temperature hydrogen furnace, keep it warm at 1400°C for 3 hours, and then cool it to room temperature with the furnace and leave the furnace. The phosphor powder obtained by the secondary reduction will be classified again by an airflow classifier to obtain Phosphor powder with a central particle size (D50) ≤ 3.2 μm, D10 ≥ 1 μm, and D90 ≤ 6 μm.

Use deionized water (or distilled water) to wash the graded phosphor powder with deionized water at 100°C until the supernatant is neutral, then weigh 2.85g (0.5-20%) of MgCl ₂ and prepare it with the phosphor powder at a concentration of 2.5 % phosphor suspension, ultrasonically dispersed, kept at 80°C in a water bath, while stirring the phosphor suspension at a speed of 400rpm/min, dripping NH ₃ ·H ₂ O solution with a molar concentration of 0.05M at a rate of 6ml/min Quickly add the fluorescent powder suspension, adjust the pH value of the solution to 10, stop the dripping of the ammonia solution, continue to keep warm and stir for 6 hours, centrifuge, wash with deionized water until neutral, and then dehydrate with absolute ethanol at 120°C Drying, heating to 300°C in the air, holding the temperature for 60 minutes, and cooling with the furnace, the final product of aluminate blue phosphor coated with MgO film on the surface is obtained.

Example 4

1) Raw material pretreatment

According to the chemical structural formula of Ba _0.95 Mg _0.82 Al ₁₂ O ₁₉ :Mn _0.15 , 15.62 g of BaCO ₃ , 2.73 g of MgO, 50.5 g of Al ₂ O ₃ , and 1.44 g of MnCO ₃ were weighed. Place in a _HNO3 aqueous solution with a molar concentration of 0.1M, adjust the pH value to 3, stir for 60 minutes, let stand and soak for 6 hours, centrifuge and dehydrate, and then wash with distilled water (or deionized water) until the supernatant is neutral.

2) wet mixing

Weigh 1.41g of NH ₄ F (0.5-10%) and dissolve it in the phosphor powder raw material suspension that has been washed to neutral, stir for 50 minutes, let stand for 3 hours, and dry at 80°C.

3) One-time high-temperature air synthesis

Put it in a high-temperature furnace under an air atmosphere, heat it to 1550 ° C, keep it warm for 8 hours, and cool it to room temperature with the furnace;

4) One-time jet milling and grading

Put the calcined powder into the jaw crusher with corundum plate as the inner liner for primary crushing, and then put the powder obtained by the jaw crusher into the corundum roller crusher for further crushing to powder state. Finally, the powder obtained by roller crushing is added to the jet mill classifier to obtain a primary firing powder with a central particle size (D50) ≤ 3.5 μm, D10 ≥ 1 μm, and D90 ≤ 7 μm.

5) Secondary high temperature reduction

Put the primary synthetic powder obtained by classification into a crucible, place it in a high-temperature hydrogen furnace, heat it to 1450°C, keep it warm for 6 hours, and cool it to room temperature with the furnace to get the fired phosphor.

(6) Secondary classification

The phosphor powder obtained by the secondary reduction will be classified again by an airflow classifier to obtain a phosphor powder with a central particle diameter (D50) ≤ 3.2 μm, D10 ≥ 1 μm, and D90 ≤ 6 μm.

(7) Surface coating

Wash the graded fluorescent powder with deionized water (or distilled water) with deionized water at 80°C until the supernatant is neutral, then weigh 3.33g (0.5-20%) of MgCl ₂ and prepare it with the fluorescent powder at a concentration of 1.5 % fluorescent powder suspension, ultrasonically dispersed for 10min, kept at 50°C in a water bath, while stirring the phosphor suspension at a speed of 100rpm/min, while stirring the phosphor suspension with a molar concentration of 0.25M NH ₃ ·H ₂ O solution at a rate of 3ml/min Add it into the fluorescent powder suspension at a dropping speed, adjust the pH value of the solution to 8, stop the dripping of the ammonia solution, continue to keep warm and stir for 3 hours, then centrifuge, wash with deionized water until neutral, and then dehydrate with absolute ethanol, 80 ℃ drying, heating to 200 ℃ in the air, holding the temperature for 30 minutes, and cooling with the furnace to obtain the final product of aluminate green phosphor coated with MgO film on the surface.

Example 5

According to the same composition as in Example 4 and the synthesis process of steps (1) to (6), phosphor powder with a central particle size (D50) ≤ 3.2 μm, D10 ≥ 1 μm, and D90 ≤ 6 μm was produced. Wash the graded fluorescent powder with deionized water (or distilled water) with deionized water at 60°C until the supernatant is neutral, then weigh 4.56g (0.5-20%) of MgCl ₂ and prepare it with the fluorescent powder at a concentration of 1.0 % phosphor suspension, ultrasonically dispersed for 15min, kept at 60°C in a water bath, while stirring the phosphor suspension at a speed of 100rpm/min, while stirring the phosphor suspension with a molar concentration of 0.2M NH ₃ ·H ₂ O solution at 5ml/min Add the phosphor suspension into the phosphor suspension at a dropping speed, adjust the pH value of the solution to 9, stop the dripping of the ammonia solution, and continue to keep warm and stir for 6 hours, then centrifuge, wash with deionized water until neutral, and then dehydrate with absolute ethanol, 80 ℃ drying, heating to 350 ℃ in the air, holding the temperature for 30 minutes, and cooling with the furnace to obtain the final product of aluminate green phosphor coated with MgO film on the surface.

Claims (10)

1. A method for producing an aluminate matrix phosphor, characterized in that the manufacture of the phosphor comprises the following steps: (1) Raw material pretreatment According to the chemical structure formula of aluminate-based phosphors, disperse various raw materials for the synthesis of aluminate phosphors into an acid solution with a molar concentration of 0.1M-2.0M, adjust the pH value to 2-5, stir and stand for soaking Centrifuge and dehydrate, then wash until the supernatant is neutral; (2) wet mixing Mix at least one compound among NH ₄ F and HBO ₃ with BaF ₂ in any weight ratio as a reaction accelerator, dissolve it in the phosphor powder raw material suspension that has been washed to neutral, stir, let it stand, and then dry it; the above reaction The dosage of the accelerator is 0.5-10% of the weight of the phosphor raw material; (3) Primary high temperature air synthesis Heat the dried powder to 1300-1600°C in an air atmosphere, keep it warm for 2-12 hours, and cool it to room temperature with the furnace; (4) Primary crushing and grading The synthesized powder blocks are crushed and classified into primary fired powders with a central particle diameter of D50≤3.5μm, D10≥1μm, and D90≤7μm. (5) Secondary high temperature reduction Put the powder obtained by one high-temperature air synthesis into a high-temperature hydrogen furnace, heat it to 1200-1550°C, keep it warm for 2-12 hours, and cool it to room temperature with the furnace to get the phosphor; (6) Secondary classification The phosphor powder obtained by the secondary reduction is classified again to obtain phosphors with a central particle diameter of D50 ≤ 3.2 μm, D10 ≥ 1 μm, and D90 ≤ 6 μm; (7) Surface coating Wash the phosphor powder after secondary classification until the supernatant is neutral, take 0.5-20% MgCl ₂ of the phosphor powder weight, and prepare phosphor suspension with a concentration of 0.2-10% together with the phosphor powder, and disperse it by ultrasonic 1. After keeping warm in a water bath, stir to form a phosphor suspension; add NH ₃ ·H ₂ O solution with a molar concentration of 0.25-2M into the phosphor suspension in a dropwise manner, and adjust the pH value of the solution to a range of 8-10 before ending the dripping. Add, continue to keep warm and stir, then centrifuge, wash with water until neutral, then dehydrate and dry, heat to 200-400°C in the air, keep warm for 30-120min, and cool with the furnace to get the final surface coated with MgO film aluminate phosphor finished product. 2. according to the manufacture method of the described aluminate matrix fluorescent powder of claim 1, it is characterized in that the acid solution described in step (1) is _HNO3 or HCl solution, and stirring time is 30～240min, and standing immersion time is 6 ~48h, wash with distilled or deionized water until the supernatant is neutral. 3. according to the manufacture method of aluminate matrix fluorescent powder described in claim 1, it is characterized in that after the stirring time in step (2) is 30～300min, standing time is 1～12h, and drying temperature is 80～200 ℃. 4. According to the manufacturing method of the aluminate matrix phosphor according to claim 1 or 3, it is characterized in that in step (2), the weight of the reaction accelerator accounts for 1-5% of the total weight of the phosphor raw material. 5. according to the manufacture method of the described aluminate matrix fluorescent powder of claim 1, it is characterized in that step (4) described primary pulverization classification is that the powder that synthesizes is first added in adopting jaw crusher to carry out primary crushing, and then The powder obtained by crushing the jaw crusher is added to the corundum roller crusher for further crushing to a powder state, and finally the powder obtained by the roller crushing is fed into the jet crushing and classifying machine for classification. 6. According to claim 1 or 5, the method for producing aluminate-based fluorescent powder is characterized in that the central particle diameter D50 of the primary fired powder obtained by crushing and classifying in step (4) is ≤3.2 μm, and D10≥1 μm , D90≤6μm. 7. The method for producing aluminate matrix phosphor according to claim 1, characterized in that the secondary classification in step (6) is performed by an airflow classifier. Phosphor powder with central particle diameter D50≤3.0μm, D10≥1μm and D90≤6μm is obtained. 8. According to the method for producing aluminate matrix phosphor according to claim 1, it is characterized in that in step (7), the phosphor powder after classification is washed with deionized water or distilled water at 40-100°C until the supernatant is neutral; The time for ultrasonic dispersion is 10-30 minutes; the temperature of water bath insulation is 20-60 ° C, and the time is 30-120 minutes; the phosphor suspension is stirred at a speed of 100-800 rpm/min by a high-speed mixer; the NH ₃ ·H ₂ O solution The dropping rate is 2-50ml/min, and the time for keeping warm and stirring after the speed-dropping is 0.5-6h; after centrifugation, wash with deionized water until neutral, then dehydrate with absolute ethanol, and dry at 80-150°C Dry. 9. The method for producing aluminate matrix phosphor according to claim 1 or 8, characterized in that in step (7), MgCl ₂ accounts for 2.5-7.5% of the phosphor weight. 10. The method for producing aluminate-based phosphor according to claim 1 or 8, characterized in that in step (7), NH ₃ ·H ₂ O is added dropwise to adjust the pH value of the solution to 8-9.