JPH0625715B2 - Fluorescent X-ray analysis sample preparation method and apparatus thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for preparing a sample for fluorescent X-ray analysis in which a powder sample is melted in a platinum crucible and glass beads are prepared, and an apparatus therefor.

(Prior Art) Conventionally, as a method for producing a glass bead for preparing a sample for fluorescent X-ray analysis, a melting agent of sodium tetraborate or lithium tetraborate in an amount of 7 to 10 times the sample weight 1 is peeled off. When using a promoter, weigh out an optimum amount of sodium bromide, potassium bromide, sodium bromate, sodium nitrate, sodium iodide, etc., put them in a platinum crucible and stir them, then use an electric furnace or high frequency wave. The glass beads were produced by heating and melting in an induction furnace.

When sodium tetraborate is used as the melting agent, the heating temperature is generally a constant temperature between 1000 and 1050 ℃, and when lithium tetraborate is used, it is a constant temperature between 1050 and 1100 ℃, and the heating time is The electric furnace was heated for 8 to 20 minutes, and the high frequency induction furnace was heated for 3 to 5 minutes while stirring the melt.

(Problems to be solved by the invention) However, in this method, when a metallic element is present in the sample, the platinum crucible reacts with the metal to form a platinum alloy, which damages the platinum crucible and causes the platinum bead contact surface of the glass bead to come into contact. Is not smooth, and the analysis accuracy of the fluorescent X-ray analyzer is deteriorated.

In recent years, in order to solve the above problems, a method effective when a metallic element is present in a sample has been proposed in Japanese Patent Application Laid-Open No. 53-69096 as a method for preparing a fluorescent X-ray analysis sample. In this method, the sample is placed in a porcelain dish, baked in a heating furnace at a temperature of about 900 ° C., transferred to a platinum crucible, mixed with a melting agent, and heated again in the heating furnace to melt. This method requires a long time of 15 to 30 minutes because the baking in the porcelain dish is an oxidation reaction of the metal in the air atmosphere, and when the sample is transferred to a platinum crucible, some of the sample is placed in the porcelain dish. There is a drawback that it sticks and the analysis accuracy deteriorates, and it is not yet satisfactory.

Further, as a method for improving this drawback, Japanese Patent Application Laid-Open No. 57-54846 proposes a method for preparing a sample for fluorescent X-ray analysis. In this method, a flammable fibrous substance is laid on the bottom of a platinum crucible, a sample is placed on the bottom, a melting agent is added after calcination, and the mixture is heated and melted to produce a glass bead. However, this method also has the drawback that the platinum crucible is unavoidably damaged if the sample contains a large amount of metallic elements, and the operation is complicated.

The present invention provides a method for producing a glass bead in a short time, which does not cause damage to a platinum crucible at all even when a sample contains a large amount of metallic elements, and can be accurately analyzed, and an automatic production apparatus thereof.

Method (for means for solving the problems) The present invention provides a fluorescent X-ray sample preparation method for analysis of making glass beads were thawed powder sample in a platinum crucible, the sample, V ₂ O Other oxidant of the melting agent ₅ , NaClO ₃ , K
Add either IO ₃ or KClO ₃ in the range of 0.5 to 1 with respect to the sample weight of 1, and when adding to the platinum crucible, first add 40 to 70% of the amount of the melting agent used.
Oxidant, remaining melting agent, or oxidant, sample,
Add the remaining melting agent in that order, add the release agent at the end, and put the contents in the platinum crucible first in the oxidation temperature range
For fluorescent X-ray analysis, which is characterized by holding at 0 to 900 ° C. for 5 to 15 minutes to oxidize, and then holding at 1050 to 1200 ° C. in the melting temperature range for 3 to 10 minutes to melt to prepare a glass bead. A sample preparation method, wherein the apparatus of the present invention is a sample preparation method for fluorescent X-ray analysis in which a powder sample is melted in a platinum crucible to produce a glass bead, in which a plurality of platinum crucibles are held by a flange above the platinum crucible. A platinum crucible turntable that has a plurality of holes in the circumferential direction, is rotatable in the horizontal direction, and moves vertically in the vertical direction, and the platinum crucible of this turntable is located under the orbit that rotates in the circumferential direction. Adjacent to the turntable for the platinum crucible and the movable melting agent hopper and oxidizer hopper that can be adjusted with the balance and the cutting device attached to the bottom respectively, with each cutting position being centered on the balance table. A plurality of sample containers are stored in the circumferential direction and can be rotated in the horizontal direction. The sample container is located between the turntables and the sample container is located between the turntables. The sample container is placed in the platinum crucible on the platinum crucible turntable. The sample loading arm turns the sample inside, and after loading, the empty sample container returns to the original position of the sample container turntable, and the platinum crucible of the platinum crucible turntable rotates in the circumferential direction. Stripping agent solution automatic burette having a discharge position on the orbit, a high frequency induction furnace for heating the platinum crucible, a cooling stand for air cooling the heated platinum crucible, the platinum crucible turntable, the high frequency induction. The platinum crucible on the platinum crucible turntable is located between the furnace and the cooling table, set in the high-frequency induction furnace after being heated, and after heating, the platinum crucible of the high-frequency induction furnace is acquired and the cooling table is set. Place the glass crucible on the cooling table after cooling and hold the platinum crucible on the cooling table to return it to the platinum crucible turntable. Turntable, the platinum crucible turntable and the glass bead storage turntable are located between the platinum crucible and the glass beads in the platinum crucible are sucked and adsorbed by a negative pressure method, and taken out.
An arm for taking out the glass bead for placing the platinum crucible contact surface downward on the turntable for storing the glass bead,
A sample preparation device for fluorescent X-ray analysis, comprising a controller for sequentially performing the above-mentioned series of operations.

(Action, Example) Types of analysis samples are sinter, sintering raw material, iron ore, blast furnace slag, converter slag, converter slag, hot metal treatment slag before converter charging, falling dust, scale, silica stone, limestone, fluorite , Continuous casting powder, blast furnace ash, etc.
Some include 5%. In the conventional method, when these metallic elements were present in a large amount in the sample, the metallic elements could not be completely oxidized, and it was unavoidable to form a platinum alloy with the platinum crucible and the metal.Therefore, an oxidizing agent was added to the sample. It was decided to promote the oxidation of metal elements.

As the oxidizing agents, NaClO ₃ , KIO ₃ , KClO ₃ , V ₂ O ₅ and CeO ₂ were selected, and the oxidizing ability of each metallic iron was investigated.
From the results shown in the figure, the oxidizing agents were NaClO ₃ , KIO ₃ , and KClO.
₃ , V ₂ O ₅ is used, and the oxidation reaction time is 5 to 15 minutes. Further, from the results shown in FIG. 3, the temperature at which the oxidation reaction is carried out is in the range of 800 to 900 ° C., and the amount of the oxidizing agent added is in the range of 0.5 to 1 with respect to 1 weight of the sample. Regarding the oxidation reaction time, if the oxidation reaction time is shorter than the above range, the oxidation of metallic iron is not sufficiently performed. On the other hand, even if the oxidation reaction time is long, the oxidation of metallic iron has already been completed and the time is wasted. When the oxidation temperature is lower than the above range, the metal iron is not sufficiently oxidized, and when it is higher than the above range, the metal iron and the platinum crucible react simultaneously with the oxidation reaction of the metal iron, and the platinum crucible is damaged. When the amount of the oxidizing agent added is less than the above range, the metallic iron is not sufficiently oxidized, and when it is more than the above range, the oxidizing agent is wasted.

Next, the order of adding the melting agent, the oxidizing agent, the sample, and the release agent to the platinum crucible, which does not damage the platinum crucible when the glass beads are produced by melting the sample under the above-mentioned oxidizing agent use conditions, Add 40 to 70% of the amount of the melting agent used, and
Sample, oxidant, remaining melting agent, or oxidant,
In this order, the sample and the remaining melting agent are charged in that order, and the release agent is added last. As shown in Table 1, when the glass beads were prepared in the above order, the platinum crucible was not damaged, and the prepared glass beads were homogeneous because the reaction between the sample and the melting agent was sufficiently performed.

On the other hand, damage is observed in the platinum crucible in the conventional method, that is, the method of stirring the contents of the platinum crucible before heating. Even if an oxidizer is used, if it is stirred in the platinum crucible, there will be a part where the platinum crucible and the sample come into direct contact,
That part of the platinum crucible reacts with metallic iron to form an alloy. On the other hand, according to the method of the present invention, there is almost no chance that the sample and the platinum crucible come into direct contact with each other during the oxidation reaction time as shown in FIG.

Furthermore, if the amount of the melting agent initially charged to the platinum crucible is less than the above range, damage to the platinum crucible is recognized, and the glass beads produced are inhomogeneous due to insufficient reaction between the sample and the melting agent. On the other hand, when the amount is more than the above range, the platinum crucible is not damaged, but the glass beads produced are not homogeneous.

FIG. 4 shows an embodiment of the device of the present invention.

The sample container turntable 1 can be loaded with a plurality of sample containers 2 along which the sample container 2 can be loaded, and can be horizontally rotated.
That is, it can rotate clockwise and counterclockwise.

The platinum crucible turntable 3 has a plurality of holes formed in the circumferential direction, and the platinum crucible 4 is held by the upper flange 5 in the opening. The platinum crucible turntable 3 is rotatable in the horizontal direction, that is, it can be rotated in the clockwise direction and the counterclockwise direction, and can also be vertically moved.

The sample loading arm 6 has a chucking mechanism 7 and a turning mechanism 8 at its tip, holds the sample container 2 in a fixed position of the sample container turntable 1, and holds the platinum crucible 4 in a fixed position of the platinum crucible turntable 3. After moving up and turning, the sample in the sample container 2 is put into the platinum crucible 4 and then turned back to the original position to return the sample container 2 onto the turntable 1 for sample container. There is.

The melting agent hopper 9 and the oxidizing agent hopper 10 respectively have a melting agent cutting device 11 and an oxidizing agent cutting device 12 at the bottom, and the support bases 13 of both hoppers move horizontally to cut the melting agent and the oxidizing agent predetermined. It can be done at the position.

A balance 14 is installed below the platinum crucible turntable 3, and when the platinum crucible turntable 3 descends vertically, the bottom of the platinum crucible 4 is placed on the balance table 15 of the balance 14 of the balance 14. The weight of the platinum crucible 4 can be weighed.

The stripper solution automatic buret 16 is at the solution dropping position 1
7 is on the platinum crucible 4 at a fixed position on the platinum crucible turntable 3, and the solution can be dropped into the platinum crucible 4.

The platinum crucible moving arm 18 has a chucking mechanism 19 at its tip, the arm axis moves up and down in the vertical direction, and the arm rotates horizontally. The platinum crucible turntable 3 has a fixed position on the turntable 3. Grab the platinum crucible 4 from
After setting the sample in the high frequency induction furnace 20 at the sample setting position 21, after melting, grasp the platinum crucible at the sample setting position 21 and set it on the sample cooling table 22. After cooling, grasp the platinum crucible on the sample cooling table 22. , It can be set in a fixed position on the platinum crucible turntable 3.

The high-frequency induction furnace 20 can control the heating temperature of the sample by adjusting the additional current, and at the same time has a structure having an ordinary platinum crucible swinging mechanism, and the sample cooling table 22 has a compressed air below the outer surface of the platinum crucible. It is designed to be sprayed.

The glass bead taking-out arm 23 has a suction device 24 by an air negative pressure system at its tip, and is configured to move vertically in the vertical direction, and the arm moves horizontally, so that the position on the platinum crucible turntable 3 is fixed. The adsorption device 24 descends and adsorbs the glass bead in the platinum crucible at, and the adsorption device 24 ascends after adsorption, the arm moves to a fixed position on the glass bead storage turntable 25, and the adsorption device 24 descends. Then set the glass beads. When discarding the glass beads, they are moved to the disposal port 26 and discarded.

The glass bead storage turntable 25 can be loaded with a plurality of glass beads along its circumference, and can be horizontally rotated.
That is, it can rotate clockwise and counterclockwise.

Next, a control device for sequentially performing a series of operations of this device will be described.

First, one or a plurality of (36 in this embodiment) samples are put into the sample container 2 on the turntable 1 for a sample container, and one or a plurality (12 in this embodiment) of platinum crucibles. 4 is set on the platinum crucible turntable 3.
In this state, the start switch is turned on to start the glass bead manufacturing process.

The platinum crucible turntable 3 is horizontally rotated to a position where the platinum crucible to be used can be set on the balance table 15, and then descends to set the platinum crucible on the balance table 15. After the weight of the platinum crucible has been weighed, the melting agent cutting device 11 is driven to cut the melting agent into the set amount of platinum crucible and store the actual weight.

Next, the platinum crucible turntable 3 is horizontally rotated to a position where the sample can be loaded into the platinum crucible, and then the sample loading arm 6 is driven to grab a predetermined sample container 2 to load the sample into the platinum crucible. Charge the sample container and return it to the original position after completion. Next, the platinum crucible turntable 3 rotates horizontally until the platinum crucible reaches the position of the balance table 15, and then descends to set the platinum crucible on the balance table 15 and weigh and store the sample weight. .

After weighing the sample weight, the support 13 is moved and the oxidizer cutting device 12 is driven to load the oxidizer by the set weight of the previously weighed sample weight.

After the oxidizer is charged, the support base 13 is moved, and then the melting agent cutting device 11 is driven to charge only the weight of the melting agent of the set magnification of the sample weight less the weight of the melting agent previously charged.

Regarding the order of charging the sample and the oxidizing agent into the platinum crucible, it is possible to charge the oxidizing agent first and then charge the sample. In this case, the amount of the oxidizing agent is set to be the set amount regardless of the weight of the sample.

After the cutting of the melting agent is completed, the platinum crucible turntable 3 rises in the vertical direction, and then the platinum crucible rotates in the horizontal direction until the dropping solution solution dropping position is reached. Next, the release agent solution automatic buret 16 is driven to drop a predetermined amount of the release agent solution into the platinum crucible.

After the dropping is completed, the platinum crucible turntable 3 horizontally rotates the platinum crucible to a position where the platinum crucible moving arm 18 can be operated. Next, the platinum crucible moving arm 18 is driven to grab the platinum crucible and set at the sample setting position 21 of the high frequency induction furnace 20.

After the platinum crucible is set, the high frequency induction furnace 20 is driven, and the contents of the platinum crucible are first kept at a predetermined temperature of 800 to 900 ° C. for a predetermined time of 5 to 15 minutes, and then a normal melting temperature of 1050 to 1200. Melt by holding at a predetermined temperature between 0 ° C. and a predetermined holding time of 3 to 10 minutes which is a normal holding time.

After the melting is completed, the platinum crucible moving arm 18 is driven,
The platinum crucible located on the sample setting position 21 is grabbed and set on the sample cooling table 22. After the platinum crucible is set, compressed air is blown onto the lower portion of the outer surface of the platinum crucible from the nozzle of the compressed air pipe connected to the sample cooling table 22 to cool the platinum crucible.

After completion of cooling, the platinum crucible moving arm 18 is driven to grab the platinum crucible on the sample cooling table 22 and set it at a predetermined position of the platinum crucible turntable 3. After the setting is completed, the platinum crucible turntable 3 horizontally rotates the platinum crucible to a position where the glass bead taking-out arm 23 can be operated. Next, the glass bead taking-out arm 23 is driven, and the adsorption device 24 descends into the platinum crucible to adsorb the glass beads. After adsorption, adsorption device 24
Rises, and then the glass bead take-out arm 23 moves horizontally to turn the glass bead storage turntable 2
The adsorption device 24 descends to a predetermined position 5 to set the glass beads.

After setting the glass beads, the glass bead storage turntable 25 rotates horizontally to prepare for the next glass bead set.

The glass beads are produced by the above series of operations, but when the inside of the platinum crucible needs to be cleaned, the following steps are carried out in accordance with the above operations.

First, a predetermined amount of a melting agent is cut out in a platinum crucible and then dropped into a stripping agent solution. This platinum crucible is set in a high-frequency induction furnace, held at a predetermined temperature for a predetermined time, melted, and cooled. This glass bead is disposed of in the disposal port 26.

The above platinum crucible is washed every time the glass beads of the sample are produced.
Alternatively, a plurality of platinum crucibles can be continuously used.

(Effects of the Invention) As described above, according to the present invention, even when a large amount of metallic elements are present in a sample, a platinum bead is not damaged at all, and a glass bead that can be accurately analyzed is automatically and in a short time. It has an excellent effect of producing.

[Brief description of drawings]

FIG. 1 is a diagram showing the oxidation state of a sample by the method of the present invention, and FIGS. 2 (a) and 2 (b) are diagrams showing an example of the results of investigation of the oxidizing ability of metallic iron by various oxidizing agents and the optimum oxidation reaction time, FIGS. 3 (a) to (d) are diagrams showing an example of the optimum oxidation reaction temperature and the optimum oxidant addition amount investigation result. The conditions for charging the sample, etc. into the platinum crucible are: 3.5 g of melting agent + 0.7 g of sample + oxidizing agent. 0.7 g
+3.5 g of melting agent, and FIG. 4 is a plan view showing an embodiment of the apparatus of the present invention. A ... Melting agent, B ... Oxidizing agent, C ... Sample, D ... Remaining melting agent, E ... Release agent, 1 ... Sample container turntable, 2 ... Sample container, 3 ... Platinum Crucible turntable, 4 ... Platinum crucible, 5 ... Tsuba, 6 ... Sample loading arm, 7 ... Chucking mechanism, 8 ... Rolling mechanism, 9
...... Melting agent hopper, 10 ...... Oxidizing agent hopper, 11 ...
… Melting agent cutting device, 12 …… Oxidizing agent cutting device, 13
…… Support stand, 14 …… Balance, 15 …… Balance stand, 16 ……
Release agent solution automatic buret, 17 ... solution dropping position,
18 ... Platinum crucible moving arm, 19 ... Chucking mechanism, 20 ... High-frequency induction furnace, 21 ... Sample setting position, 22 ... Sample cooling stand, 23 ... Glass bead removing arm, 24 ... Adsorption Equipment, 25 ... Turntable for glass bead storage, 26 ... Disposal port.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Miyuki Shimizu 5-3 Tokai-cho, Tokai-shi, Aichi Nippon Steel Co., Ltd. Nagoya Steel Works (56) References JP-A-58-123441 (JP, A) JP-A-60-27847 (JP, A) JP-A-61-41948 (JP, A) JP-A-51-74689 (JP, A)

Claims (2)

[Claims] 1. A method for preparing a sample for fluorescent X-ray analysis, which comprises melting a powder sample in a platinum crucible to prepare a glass bead, wherein V ₂ O ₅ and NaClO are used as oxidizing agents in addition to the sample and the melting agent.
₃ , KIO ₃ , or KClO ₃ should be added in the range of 0.5 to 1 with respect to 1 of the sample weight.
0 to 70%, then sample, oxidizer, remaining melting agent in that order, or oxidizing agent, sample, remaining melting agent in that order, and finally release agent, and platinum crucible First of all, set the middle contents to 800-900 in the oxidation temperature range.
Hold at 5 ° C for 5 to 15 minutes to oxidize, then in the melting temperature range
A method for preparing a sample for fluorescent X-ray analysis, which comprises holding at 1050 to 1200 ° C. for 3 to 10 minutes to melt to prepare a glass bead. 2. A sample preparation apparatus for fluorescent X-ray analysis for melting a powder sample with a platinum crucible to prepare glass beads, wherein a plurality of platinum crucibles are circumferentially opened so that a plurality of platinum crucibles are held by a flange on the upper part of the platinum crucible. However, a platinum crucible turntable that is rotatable in the horizontal direction and that moves up and down in the vertical direction, a balance located below the orbit that the platinum crucible of this turntable rotates in the circumferential direction, and a cutout at the bottom, respectively. Attached to the device, each cutting position is a movable melting agent hopper and oxidizer hopper that can be adjusted with the balance center, and is adjacent to the platinum crucible turntable, and stores a plurality of sample containers in the circumferential direction. A turntable for the sample container that can be rotated in the horizontal direction, and a sample container that is located between the two turntables and holds the sample container in the platinum crucible on the platinum crucible turntable. The sample loading arm turns the sample inward and returns the empty sample container to the original position of the sample container turntable, and the platinum crucible of the platinum crucible turntable moves in the circumferential direction. A stripper solution automatic burette having a discharge position on a rotating orbit, a high-frequency induction furnace for heating a platinum crucible, a cooling stand for air-cooling the heated platinum crucible, and a turntable for the platinum crucible, The platinum crucible on the platinum crucible turntable is located between the high-frequency induction furnace and the cooling table, set in the high-frequency induction furnace after being heated, and after heating, the platinum crucible of the high-frequency induction furnace is set in the cooling table after cooling, and the cooling table is set after cooling. Hold the upper platinum crucible and return it to the platinum crucible turntable. Move the platinum crucible moving arm and the glass bead that is adjacent to the platinum crucible turntable. A glass bead storage turntable for storing several glass beads, and the glass bead in the platinum crucible located between the above-mentioned platinum crucible turntable and glass bead storage turntable are sucked and sucked out by a negative pressure method of air, and the glass bead is removed. An apparatus for preparing a sample for fluorescent X-ray analysis, comprising an arm for taking out a glass bead for placing a platinum crucible contact surface on a turntable for storage, and a controller for sequentially performing the above series of operations.