JPS58167426A - Preparation of oxysulfate from rare earth element - Google Patents

Abstract

PURPOSE:To obtain oxysulfate of a rare earth element having a quality with little variation, by roasting a reaction precipitate of rare earth element ions with sulfuric acid ions and urea or a derivative thereof. CONSTITUTION:Salts, e.g. sulfates, chlorides, formates or acetates, of one or more rare earth elements are dissolved in water to prepare rare earth element ions. Sulfuric acid, a quaternary ammonium salt of the sulfuric acid or pyridinium sulfate, is dissolved in water to prepare sulfuric acid ions. The above- mentioned rare earth element ions are reacted with the sulfuric acid ions and urea or a derivative thereof in an aqueous solution. The resultant precipitate is then roasted to give easily the aimed oxysulfate of the rare earth elements with little variation in quality.

Description

[Detailed Description of the Invention] The device relates to a new preparation technology for oxysulfate of rare earth elements.Compared to the conventional production method, the sm production operation is 1 time, and the obtained side is It is a timely product that has less parasitic properties in its crystal quality. Furthermore, the rare earth element oxysulfate obtained by the production method of the present invention.

It is an excellent fluorophore substance.

Oxysulfurate of a rare earth element is a metal compound that can be represented by the general formula VLchohe (804) (Lzen; rare earth element), and as a method for producing this compound, A method of thermal decomposition has been used. This method may be because the heat distribution reaction at high temperature is commonly used, but the difference between the heat distribution temperature of the sulfate and the heat distribution temperature of the oxysulfate, which forms the II crystal, is not large, and the product is It always contained oxides produced by thermal scaling of oxysulfate, or undecomposed compounds. moreover.

Small variations in the particle size of the raw sulfate, the amount filled in the incense pot, the roasting time, the roasting temperature, etc. can result in significant changes in the quality of the product, making it difficult to produce rare earth element oxysulfates on an industrial scale. was difficult.

In the process of researching the synthesis of inorganic materials used in urine xvh, the present inventors discovered and produced extremely interesting reactions, leading to the present invention.

The structure of the present invention is as follows.

A method for producing rare earth element oxysulfate, which comprises roasting the precipitate obtained by reacting one or more rare earth element ions, sulfate ions, and urea or its derivatives in an aqueous solution. be.

The details of the present invention will be described below.

In the present invention, the rare earth elements are elements of the lanthanide group, namely lanthanum, cerium, praseodymium, neodymium, glomethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
It is a general term for 17 elements including scandium and yttrium.4. , rare earth element ions are selected from these or water-soluble salts of two or more elements, such as inorganic salts or organic salts such as sulfates, chlorides, nitrates, sulfur salts, acetates, etc. It can be obtained by dissolving it in water, or it can be obtained by dissolving a compound, hydroxide, etc. in sulfuric acid.

It may also be something obtained by solving Shun of Shiotetsutatsu. That is, anions other than sulfate ions, such as chloride ions and nitrate ions, may be contained in the Jl layer.

The sulfate ions mixed as raw materials in this @faKM are:
It is obtained by dissolving sulfuric acid, sulfates of rare earth elements, quaternary ammonium salts of sulfuric acid such as ammonium sulfate, and salts of the viridinicum sulfate group in water. Represents a group, etc. In the case of large areas, islands or large quantities, the 111 urine bulk derivatives become insoluble in water and hot water, making this use undesirable.

In carrying out the present invention, there is no particular limitation on the degree of filtration of the rare earth element ions in the mixed aqueous solution serving as the raw material. The chemical reaction used in the present invention is a reaction in water solution, and the product becomes solid and exits the reaction system. (Even if it is filled and remains as a precipitate, as the reaction progresses, the solution will be released and used for the reaction.

In addition, the amount of sulfate ions in the mixed aqueous solution that is the raw material is determined based on the structure of oxysulfate, which is the target product.
It is clear that more than 2 moles is required. When the molar ratio of sulfate ions to rare earth element ions is 14 or more,
All products returned are the same.

In addition, the amount of urea is the raw material for rare earth element ions.

Depending on the quality of the raw material for sulfate ions, the amount of urea required will be large if there is free sulfuric acid or if sulfuric acid itself is used as a raw material for sulfate ions.

That is, the precipitate, which is an intermediate of the product of the present invention, is decomposed by Shun and is decomposed by free sulfuric acid.
This is because it is necessary to neutralize the acid with ammonium ions, which are one of its decomposition products. If the amount of urea used is too small, the yield will be low (and the preferred amount is equal to or greater than the number of moles of rare earth element ions. The quality of the side crystals will not change even if more than the amount of rare earth ions is present; rather, considering the decomposition of the raw material urea during storage and the increase in reaction mode, it is practical to use 6 to 8 times the molar amount of rare earth element ions. It is.

In order to proceed with the decomposition reaction of urea, the raw material water *tt-70℃
Heat KJI above or at room temperature, wrinkle water 11[
Urease, which is a potassium urea degrading enzyme, is added to carry out the reaction. When carrying out thermal decomposition, the preferred reaction temperature is 1
The range is 1G-1001:.

If the temperature is lower than this, the degree of decomposition of urea will be small and a very long reaction time will be required. Furthermore, when Frease is used, the amount thereof is not limited to 41, but the reaction proceeds more quickly when the amount added is large. In that case, the pH of the aqueous solution is the optimum pH for urease! 6,
It is desirable that it is 4 to 7.6. Since the enzyme activity decreases at a pH outside this range, the pH is adjusted to the optimum pH of 48 using a suitable adjusting agent.

The reaction time varies depending on the reaction temperature, the amount of urea added, the amount of urease added, and the species of rare earth element, but as a guide, the reaction is completed in 1 to 5 hours after the reaction solution becomes cloudy. The value of the precipitate changes with the passage of reaction time,
Although its structure is still unknown, regardless of the composition of the precipitate at this time, the product obtained by roasting it is an oxysulfate of rare earth elements.

In carrying out the present invention, the roasting temperature of the precipitate is 600
-1200℃ range S is suitable, more preferably 700℃
It is in the range of ~800°C. In addition, the roasting time varies depending on the degree of roasting, etc., but in the above roasting temperature range s,
The time is appropriate.

That is, a low roasting temperature is not only economical but also preferable in terms of preventing the roasted raw material from further thermal decomposition and becoming oxidized, and the temperature is 700 to 00°C. That's why. However, when making oxysulfate containing several oxides as impurities, higher temperatures,
Specifically, fi5 roasted at 1200℃ is
There is a 5M value in that crystal adjustment can be achieved in hours.

In the present invention, rare earth element ions, sulfate ions and urea are mixed in water S* as raw materials.

Water-soluble salts of the elements added to the matrix as activating materials during the production of ordinary phosphors, i.e., tetrabium, terbium, bismuth, and chloride, nitrates, etc.
By adding sulfur sI salt or the like, it is possible to produce a phosphor based on oxysulfate of a rare earth element.

The degree of activating material is such that the number of moles of ions of the activating element is 11
&l-10 of the peak number of ions of rare earth elements that make up the body
16 is suitable, and the optimum amount varies depending on the combination of elements.

The phosphor obtained in this way is a conventionally known oxysulfate-based phosphor, that is, a rare earth element as a base and each sulfate of the element that activates it are mixed and roasted at high temperature. Compared to the method of baking, pure oxysulfate is obtained, so the brightness is higher and there is less backlash.

Incidentally, after roasting is performed under the above-mentioned roasting conditions to once generate a phosphor, 1.
By re-roasting the material once or more than three times, a phosphor with better luminous efficiency can be obtained.

According to the present invention, sulfates of rare earth elements can be obtained by roasting for many hours at Tori-temperature, so that the structure of
This is accompanied by equipment corrosion, durability deterioration, and environmental pollution due to the generation of potassium sulfur dioxide gas, etc., and in addition, it is possible to use pure tx 4h to produce oxysulfate at relatively low temperatures and in a short period of time. By roasting, it has become possible to obtain high axiality and almost no generation of harmful gases such as sub-II* gas.

Furthermore, the production method of the present invention has the advantage that the particle size can be controlled by adjusting the reaction time, etc., and that it is possible to produce powder with a narrow particle size distribution. Moreover, the phosphor made of rare earth element oxysulfate obtained in this way is compared to 〇 obtained by the conventional manufacturing method.
The present invention has great practical significance also from the point of view that brightness is uniform and there is little flickering.

Examples will be described below, but the present invention is not limited to the following examples, which do not go beyond the gist of the invention.

Practical example] Dissolve the raw materials having the compositions listed in mul~3 in Table 1 in water of each IA, and add 9 SCk under stirring! The precipitate produced by the MI reaction for a period of time was collected, dried, and then roasted for 2 hours at 5 ooc.
All the powders obtained by 0 or more operations were white and j1! According to an electronic examination, the grain shape was plate-like. In addition, the xs1 diffraction of each powder is shown in row 7,
II I II-$113 WiK indication, Taka, I
When calculating the Iif relation from EI, the representation (inversion) is obtained, respectively.
K becomes ~0. For gadolinium, A37M
Card values and good sentences are seen, and for Yztrif 5, although it is not in the 81 card, gadolinium 11 2
(A) Table 2 @Table 20
It can be said that he is well within the III degree of the xiaia fold obtained by martial arts.

Comparative Example 1 Yttricum sulfur (80a)a@5)4010f was roasted at SOO°C and 1000°C for 3 hours each. SOO℃
of the powder obtained by roasting x! The results of one diffraction are shown in Figure 4, and as can be seen from this figure, 800
℃ roasting did not produce yttrium oxysulfate. Further, the results of X-diffraction of the powder dispersed by roasting at 1000°C are shown in FIG. The diffraction ratio (ter/w-) was co-occurring with the peak of yttrium oxysulfate, and there were also peaks other than this compound.As can be seen from these results, during roasting at 1000°C, some yttrium oxysulfate was formed. (However, other compounds were also mixed.

Further, FIG. 6 shows the particle size distribution of the yttrium oxysulfate powders obtained in Example 1 and Comparative Example 1 (roasted at 1000° C.). As you can see from the diagram, i
The particle size of the oxysulfate obtained by c1 was smaller than that obtained by the conventional method, and its distribution was sharp.

Actual example 4 Yttrium chloride ycchi・1l) 1t0 45.
50fi1jl Aymoniu A (NH4), so,
3o as urea
The above substance was dissolved in 1 t of water and reacted under stirring at 95°C for 3 hours. The resulting precipitate was roasted at 800°C for 2 hours. When the white powder obtained by the above procedure was subjected to X* diffraction, a single fold pattern similar to that of the yttrium oxysulfate obtained in Example IKN was obtained. Furthermore, when the molar ratio of Y and 8 (V8) was added by -1 by the same method as in % Collection Example 4, the result was 103.

The above results prove that the obtained powder is pure yttrium oxysulfate. Note that the yield was 96 mo.

夷mExample 5 Yttri sulfate (80i)s”8 for 0 46.
O5f Mouse
60F urease
2. The above substance is dissolved in 1 t of water K11 l. 1) J
(6,5), the precipitate produced as a result of the 411 reaction at 25°C with stirring was subjected to PNR, dried, and then roasted at 800°C for 2 hours.

X* diffraction pattern of the white powder obtained by the above procedure -
As a result, a diffraction pattern similar to that of the yttrium oxysulfate obtained in Example 1 was obtained. Furthermore, when the molar ratio of Y and 8 (Y/8) was measured using Examples 1 to 3 and N11 f:, a value of 2.05 was obtained. The above results prove that the obtained powder is pure yttrium oxysulfate. 8, the yield was 90%.

Implementation f16 ii*Yitliu A Y, (80,), -81-1
,04L15 as europium sulfate Nut (804)s
”JI HIO1,66 under armpit
60 f A precipitate was produced as a result of reacting 1 t of mixed aqueous solution of the above substances at 95° C. for 3 hours with stirring. Xm of the white powder obtained by the above operations
When i-folding was carried out, a diffraction pattern similar to that of the yttrium oxysulfate obtained in Example IKjj was obtained. Furthermore, when the −w ratio (Y/8) of y and s was determined using the same method as in Example 1111-3, ? , 05, and the combination of europium and yttrium determined at the same time was 102 sol 14. The above results prove that pure Y (J104) with a europium activation amount of 0.0!92 f per 1 t of yttrium oxysulfate was obtained.

After packing the obtained powder into a VV sample cell and layering it, a Shimadzu fluorescent photometer RF-BOOK was set, and detection with a photomultiplier tube revealed that 101 at an excitation wavelength of 2906 m.
When the light emission in the ' direction (liquid length 41511rzA) was kept constant, a relative intensity of [57] was obtained. On the other hand, yttrium sulfate and europium sulfate were heated in the same manner as in the present example,
When the powder obtained by thermal decomposition (110 G'C, 4 hours) was measured using the same scale using the same machine, the relative strength was 3o. In other words, the phosphor whose parent substance is yttrium oxysulfate obtained by the conventional method has 1.9 times the luminance per luminescence than the phosphor whose parent substance is oxynalphate obtained by the conventional method. there were.

The yield of 8, Y, 804:1 tiu was 96 pieces.

Example 7 Yttrium sulfate-(80a)s” aito
4 L70 sulfur Hf rubium Tb, (so,)
asaHlo 1.58? Urea
60 was reacted with 1 t of a mixed aqueous solution of the above substances at 95°C for 3 hours under stirring, and the resulting precipitate 1/IkvP was collected, dried and then roasted at 800°C for 2 hours. When the white powder obtained by the above procedure was subjected to Xaa analysis, it was found that yttrium oxysulfate and 1jjIl
A diffraction pattern was obtained. Furthermore, by the same method as Examples 1 to 3.

When the molar ratio of Y and 8 (Y/8) was measured, zoi
The ratio of terbium to yttrium measured at the same time was L97so1%. Based on the above results, pure Y (804
); It is proven that Tb was obtained.

By the same method as in Example 6, the excitation wavelength was set to 375IIIa.
When the luminescence (liquid length S4aam) was measured, the luminescence brightness of this phosphor was found to be 2 of the emission brightness obtained by ．． It was twice that amount. In addition, YIOI (804);
Tb #) yield was 9511.

Example 8 Lanthanum sulfate L~(804)s・-搗0 10.
1iif Eurobic chloride h 1ucj,
Add 0.21f SO to the above substance at 100℃ for 15 minutes with stirring.
Take a portion of the precipitate produced as a result of the reaction and dry it for 75 minutes.
It was roasted at 0°C for 2 hours. When the white powder obtained by the above procedure was subjected to xlI-fraction, a diffraction pattern similar to that of the lanthanum oxysulfate obtained in Example 2 was obtained.

Furthermore, by the same method as in Example 1-8, la and 8
When the solenoid ratio (La/8) was determined by sea, it was 10M, and the ratio of U measurement um to Funtan, which was determined in the lii1mlK column, was 104go11G. Conclusion of the above
Pure L whose activation amount is o, ozzst for 1fK (lanthanum oxysulfate)
~01 (804); It is proven that Ru has been obtained.

When the luminescence (wavelength 4115 mm) was measured using the same method as in Example 6 when the excitation wavelength was 30 G, the luminance of this phosphor was found to be higher than that of lanthanum sulfate and 1III! NiPbium was added in the same proportion as in this example, a mixture L, heat content % (1
10QC, 411M) The luminescence brightness was L8 times that of the one obtained by LTEII. In addition, the yield of L～(804);i'' was 99 mm.

Example 9 Yttrium sulfate (804)s 118 pigs 0 4 shakes 75f monomethylol urea 90 The above substance was dissolved in 1 t of water and reacted at 95°C for 3 hours with stirring. As a result, the precipitate formed was PAL. .

After drying, it was roasted at 800C for 2 hours to obtain yttrium oxysulfate, )% l).

[Brief explanation of the drawing]

Fig. 1g is a graph showing the xII diffraction pattern of the powder obtained in Example 111, Fig. 3 is a graph showing the XSa diffraction pattern of the powder obtained in Example 8. 7. A needle showing the XII ■ fold pattern of the powder. No. 4811 is a needle 7 showing the X*a fold pattern of the powder obtained by roasting at 800°C in Comparative Example I.
．． No.! ! @l is a graph showing the XS diffraction pattern of the powder obtained by roasting at 1000°C in Comparative Example I, No. 6
■ indicates Example IS and Comparative Example 1 (roasted at 100℃>Ks+t
3 is a graph showing the particle size distribution of powders obtained by

Claims (1)

[Claims] (1) One or more rare earth element ions. A method for producing oxyduryaate of rare earth elements, which involves reacting sulfate ions with urea or its derivatives in an aqueous solution and roasting the resulting precipitate to produce v4I mold. ■) Claims in which the rare earth element ions are produced by dissolving inorganic or organic acid salts such as ms salts, chlorides, formates, and acetates of wrinkle elements in an aqueous solution [1$K 1
A method for producing the oxysulfate described in If. (The 37ik Shun ion is obtained by dissolving sulfuric acid, rare earth element sulfates, quaternary ammonium salts of sulfuric acid such as ammonium sulfate, and salts of pyridinium sulfate in an aqueous solution. Method for producing oxysulfate. (4) The method for producing oxysulfate according to claim 1, wherein the aqueous solution contains an activating material for a phosphor.