JP2003268366A - Treating method of fluorescent substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treating method for a fluorescent substance which can efficiently improved its dispersibility and luminous characteristics. <P>SOLUTION: The dispersibility and luminous characteristics are efficiently improved by baking a mixture of raw materials, then dispersing the baked product in liquid nitrogen or liquid helium and classifying, particularly with regard to a fluorescent substance having low water resistance, such as BaMgAl<SB>10</SB>O<SB>17</SB>:Eu; BaMgAl<SB>10</SB>O<SB>17</SB>:Eu, Mn:BaAl<SB>12</SB>O<SB>19</SB>:Mn; CaAl<SB>2</SB>O<SB>4</SB>:Eu; SrAl<SB>2</SB>O<SB>4</SB>:Eu; BaAl<SB>2</SB>O<SB>4</SB>: Eu; LiAlO<SB>2</SB>:Eu; NaKAl<SB>2</SB>O<SB>4</SB>:Eu; La<SB>2</SB>O<SB>2</SB>S:Eu; MgS:Eu; and CaS:Eu. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating phosphors used in mercury lamps, Xe excitation lamps, various displays, phosphorescent materials and the like.

[0002]

PRIOR ART Phosphors used in mercury lamps, etc.
Hereafter, a fired product obtained by firing a raw material mixture is dispersed by a dry method.
Classification after treatment or dispersion treatment with solvent
Is being manufactured. After dry dispersion treatment, dry
If you classify through the
Since it is bad, it is generally wet dispersion after dispersion treatment with water.
To obtain a phosphor after solid-liquid separation and drying.
It However, the phosphors re-aggregate during separation and drying.
As a result, the dispersibility of the phosphor decreases, and the phosphor is heated by heating during drying.
However, there is a problem in that the luminescent properties are deteriorated due to the oxidation of the.
Furthermore, BaMgAl₁₀O₁₇: Eu, BaMgAl
₁₀O₁₇: Eu, Mn, BaAl₁₂O ₁₉: Mn,
CaAl_TwoO_Four: Eu, SrAl_TwoO_Four: Eu, BaA
l_TwoO_Four: Eu, LiAlO_Two: Fe, NaKAl_TwoO
_Four: Eu, La_TwoO_TwoS: Eu, MgS: Eu, Ca
S: Eu, SrS: Eu, BaS: Eu, (Ca, S
r, Ba) Ga_TwoS_Four: Eu, (Ca, Sr, Ba) I
n_TwoS_Four: Fluorescent substance with low water resistance such as Eu
The body surface hydrolyzes or dissolves in water, and the composition changes
There is a problem that the characteristics are significantly deteriorated. Against this
However, instead of water, methanol, ethanol, IPA, etc.
The above problems are alleviated to a certain extent by using the organic solvent of
However, these organic solvents have low flash points and are harmful to humans.
Therefore, there was a problem that the workability was very poor.
Also, since it easily absorbs moisture, it can be used repeatedly.
There is a problem that the emission characteristics of the phosphor gradually deteriorate.
It was

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems, and an object thereof is to provide a method for treating a phosphor, which can efficiently improve the dispersibility and emission characteristics of the phosphor. There is.

[0004]

The inventors of the present invention have made extensive studies to solve the above-mentioned problems, and as a result, the phosphor-calcined product is dispersed in liquid nitrogen or liquid helium, and classification is performed to improve efficiency. The inventors have newly found that the dispersibility and emission characteristics of the phosphor can be improved, and have completed the present invention.

That is, the method for treating a phosphor of the present invention is
After firing the raw material mixture, place the fired product in liquid nitrogen or in liquid
Characterized by dispersion treatment in helium and classification
The phosphor is BaMgAl₁₀O₁₇: Eu, BaMgA
l₁₀O₁₇: Eu, Mn, BaAl₁₂O₁₉: M
n, CaAl_TwoO_Four: Eu, SrAl_TwoO_Four: Eu, B
aAl_TwoO_Four: Eu, LiAlO_Two: Fe, NaKAl
_TwoO_Four: Eu, La_TwoO _TwoS: Eu, MgS: Eu, C
aS: Eu, SrS: Eu, BaS: Eu, (Ca, S
r, Ba) Ga_TwoS_Four: Eu, (Ca, Sr, Ba) I
n_TwoS_Four: Especially for phosphors with low water resistance such as Eu
It is effective.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the method for treating a phosphor of the present invention will be described in detail. For example, BaM with low water resistance
In the case of gAl ₁₀ O ₁₇ : Eu phosphor, after mixing barium compound, magnesium compound, aluminum compound, europium compound and flux as raw materials,
The raw material mixture is packed in a crucible, fired in air, and fired in a reducing atmosphere. By stirring or ball milling the baked product in liquid nitrogen or liquid helium,
Alternatively, the dispersion treatment is performed by stirring with alumina beads or the like in a container containing liquid nitrogen or liquid helium, and after passing through a sieve, naturally dried to form BaMgAl ₁₀
O ₁₇ : Eu phosphor is obtained. B thus obtained
The aMgAl ₁₀ O ₁₇ : Eu phosphor has improved dispersibility and light emission characteristics as compared with a phosphor dispersed in water.

In the case of the present invention, liquid nitrogen and liquid helium have a much smaller polarity than water and have high fluidity, so that the sieve is very easy to be classified, efficient classification can be achieved in a short time, and dispersion of the phosphor can be achieved. As a result, the remaining amount of the sieve is reduced and the yield is increased. In addition, since it does not need to be heated because it is naturally dried, there is no problem that the phosphors are oxidized and the emission characteristics are reduced. There is no problem that the body re-aggregates and the dispersibility of the phosphor decreases. Furthermore, since liquid nitrogen and liquid helium are chemically inert,
Even with a phosphor having low water resistance, there is no problem that the composition of the phosphor surface is changed by water and the light emission characteristics are deteriorated, as in the case of dispersion treatment with water. Liquid nitrogen and liquid helium are at extremely low temperatures of −196 ° C. and −269 ° C., respectively, under atmospheric pressure, and the water adsorbed on the surface of the fired product solidifies, so there is no effect of water during dispersion processing. Thus, it is possible to obtain a phosphor having excellent light emitting characteristics.

[0008]

EXAMPLES Example 1 BaMgAl ₁₀ O ₁₇ : Eu
The phosphor is manufactured as follows. First, the following raw materials were weighed, and BaCO ₃ ... 0.90 mol 3MgCO ₃ .Mg (OH) ₂ .3H ₂ O ... 0.25 mol γ-Al ₂ O ₃・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 5.00 mol Eu ₂ O ₃・ ・ ・ 0 0.05 mol 1.0 part by weight of Al based on 100 parts by weight of the total amount.
It was added F _3, mixed ball mill in the magnetic pot. The obtained raw material mixture is filled in an alumina crucible with a lid and fired in air at 1500 ° C. for 8 hours. After cooling, N ₂ −
Baking is performed at 1500 ° C. for 8 hours in a reducing atmosphere of H ₂ .
1: 2: 2 by weight of baked product, liquid nitrogen, and alumina beads
The mixture was placed in a treatment container at a ratio of 1 hour, stirred for 1 hour to perform a dispersion treatment, passed through a 300-mesh sieve to remove coarse particles and agglomerated particles, and then naturally dried to obtain BaMgAl ₁₀ O ₁₇ : Eu.
Obtain a phosphor. The average particle size of the obtained phosphor is 2.5μ.
m, the median particle size is 5.2 μm, and the dispersity is 0.48. Here, the average particle size is a value measured using a Fisher sub-sieve sizer (FSSS) by the air permeation method, and the median particle size is the Coulter Multisizer II (Coulter) of the electrical resistance method. (Manufactured by K.K.) and shows the 50% value of the cumulative distribution. The dispersity is a value obtained by dividing the average particle size by the median particle size, and this is defined as the dispersity. It can be evaluated that the larger this value is, the better the dispersibility of the phosphor is.
The time required for sieving was 3 minutes, and the yield was 97%. Here, the yield represents the ratio of the weight of the phosphor after sieving to that before sieving.

[Comparative Example 1] A baked product obtained in the same manner as in Example 1 was stirred for 1 hour in pure water in an amount twice the weight,
Dispersion treatment is performed, and after passing through a 300 mesh sieve, 10
BaMgAl ₁₀ O ₁₇ : Eu after drying at 0 ° C. for 15 hours
Obtain a phosphor. The average particle size of the obtained phosphor is 2.6μ.
m, the median particle size is 6.2 μm, and the dispersity is 0.42. The time required for sieving was 10 minutes, and the yield was 9
It is 0%.

[Example 2] BaCO as a raw material_Three0.9
5 mol, 3MgCO_Three・ Mg (OH)_Two・ 3H_TwoO0.
24 mol, γ-Al_TwoO_Three 5 mol, Eu_TwoO_Three0.0
25 mol, MnCO_ThreeExcept using 0.04 mol
The same procedure as in Example 1 is performed and BaMgAl₁₀O ₁₇: Eu,
Obtain the Mn phosphor.

[Example 3] 0.9 mol of BaCO ₃ and γ-
6 mol of Al ₂ O _{3 and} 0.1 mol of MnCO ₃ were mixed, baked and treated in the same manner as in Example 1, and BaAl ₁₂ O ₁₉ : M.
Obtain n phosphor.

Example 4 0.9 mol of CaCO ₃ , γ-
1 mol of Al ₂ O _{3 and} 0.05 mol of Eu ₂ O ₃ are mixed and baked and treated in the same manner as in Example 1 to obtain CaAl ₂ O ₄ : Eu.
Obtain a phosphor.

[Examples 5 to 6] S in place of CaCO ₃
Example 4 was repeated except that rCO ₃ and BaCO ₃ were respectively used, and SrAl ₂ O ₄ : Eu phosphor and BaA were used.
An l ₂ O ₄ : Eu phosphor is obtained.

[Example 7] Al (OH) ₃ , Li ₂ CO
_{3, Fe (NO 3) 3} · 9H 2 O were wet-mixed, the mixture was dried and calcined for 2 hours at 1250 ° C., calcined product,
Liquid nitrogen and alumina balls were put into a ball mill at a ratio of 1: 2: 2 by weight to carry out a dispersion treatment, and after passing through a 300-mesh sieve, naturally dried to obtain a LiAlO ₂ : Fe phosphor.

[Example 8] Na ₂ CO ₃ 0.5 mol, K
₂ CO ₃ 0.5 mol, γ-Al ₂ O ₃ 1 mol, Eu ₂ O
_The mixture obtained by mixing 0.025 mol of ₃ is baked and treated in the same manner as in Example 7 to obtain a NaKAl ₂ O ₄ : Eu phosphor.

Example 9 La ₂ O ₃ 0.96 mol, E
After dissolving 0.04 mol of u ₂ O ₃ in nitric acid and adding an oxalic acid solution to obtain an oxalate, the oxalate is calcined at 850 ° C. for 3 hours to obtain an oxide. This oxide was placed in an H ₂ S atmosphere at 1100 °
The fired product obtained by firing for 1 hour is treated in the same manner as in Example 1 to obtain a La ₂ O ₂ S: Eu phosphor.

[Example 10] 1 mol of MgCO ₃ and Eu ₂
A mixture obtained by mixing 0.00075 mol of O _{3 and} calcining at 1300 ° C. for 2 hours and further calcining at 1200 ° C. for 2 hours in a H ₂ S atmosphere was treated in the same manner as in Example 1, Obtain the MgS: Eu phosphor.

[0018] but using CaCO _3, SrCO _3, BaCO ₃ in place of Example 11 to 13] MgCO ₃ respectively the same manner as in Example 10, CaS: Eu phosphor, SrS: Eu phosphor, BaS : Get Eu phosphor.

Example 14 Eu ₂ O ₃ 0.00075
A MgS: Mn phosphor is obtained in the same manner as in Example 10 except that 0.0015 mol of MnO is used instead of mol.

[0020] [Examples 15 to 17 except that use CaCO ₃ instead of MgCO _3, SrCO _3, BaCO _3, respectively the same manner as in Example 14, CaS: Mn phosphor, SrS: Mn phosphor, BaS : Mn phosphor is obtained.

Example 18 CaCO ₃ 0.1 mol, S
rCO ₃ 0.76 mol, BaCO ₃ 0.1 mol, Ga ₂
O ₃ 1 _mol of a mixture of Eu ₂ O 3 0.02 _{mole, H} 2 S
The calcined product obtained by calcining at 900 ° C. for 4 hours in the atmosphere was treated in the same manner as in Example 1 to obtain (Ca, Sr, Ba).
A Ga ₂ S ₄ : Eu phosphor is obtained.

Example 19 In Instead of Ga ₂ O ₃
Example 18 was repeated except that ₂ O ₃ was used.
a, Sr, Ba) In ₂ S ₄ : Eu phosphor is obtained.

Example 20 The same procedure as in Example 1 was carried out except that liquid helium was used instead of liquid nitrogen, and BaM was used.
A gAl ₁₀ O ₁₇ : Eu phosphor is obtained.

[Comparative Examples 2 to 19] The fired products obtained in the same manner as in Examples 2 to 19 are treated in the same manner as in Comparative Example 1 to obtain phosphors.

Table 1 shows Examples 1 to 20 and Comparative Examples 1 to 1.
The maintenance rate, average particle size, median particle size, dispersity, sieving time, and yield of the phosphor obtained in Example 9 are collectively compared. Here, the maintenance ratio is a value obtained by exciting the phosphor before and after the dispersion treatment with 254 nm ultraviolet rays to measure the emission intensity and obtaining it by the following formula, and this is defined as the maintenance ratio. Maintenance rate = (emission intensity after dispersion treatment / emission intensity before dispersion treatment) × 100 From the retention rates of Comparative Examples 1 to 19 shown in Table 1, all of these phosphors were maintained when dispersed with water. The rate is 95%
It is shown below that the phosphor has low water resistance.
As is clear from this table, the phosphor of the example of the present invention has a higher degree of dispersion than that of the phosphor of the comparative example, and has a high maintenance rate, and by performing a dispersion treatment with liquid nitrogen or liquid helium, water It is possible to obtain a phosphor having good dispersibility and excellent emission characteristics as compared with the case where the dispersion treatment is carried out. Further, in the case of the example of the present invention, the time required for sieving is shorter than that of the comparative example, the classification can be efficiently performed, and the yield is high.

[0026]

[Table 1]

[0027]

As described above, the fired product obtained by firing the raw material mixture is subjected to dispersion treatment in liquid nitrogen or liquid helium and then classified to obtain good dispersibility and excellent emission characteristics. The phosphor is obtained, the sieving time is shortened, the working efficiency is good, and the yield is high. In particular, the effect is great for phosphors having low water resistance.

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Claims (3)

[Claims] 1. A method for treating a phosphor, comprising firing a raw material mixture and then subjecting the fired product to dispersion treatment in liquid nitrogen or liquid helium for classification. 2. The method for treating a phosphor according to claim 1, wherein the phosphor is a phosphor having low water resistance. 3. The phosphor is BaMgAl₁₀O₁₇:
Eu, BaMgAl ₁₀O₁₇: Eu, Mn, BaAl
₁₂O₁₉: Mn, CaAl_TwoO_Four: Eu, SrAl_Two
O_Four: Eu, BaAl_TwoO_Four: Eu, LiAlO_Two: F
e, NaKAl_TwoO_Four: Eu, La_TwoO_TwoS: Eu, M
gS: Eu, CaS: Eu, SrS: Eu, BaS: E
u, (Ca, Sr, Ba) Ga_TwoS_Four: Eu, (Ca,
Sr, Ba) In_TwoS_Four: Selected from the group consisting of Eu
At least one kind of phosphor is used.
2. The method for treating the phosphor according to 2.