JP4034884B2 - Elemental analysis equipment for samples - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to elemental analysis in a sample for analyzing elements such as N (nitrogen), O (oxygen), C (carbon), S (sulfur), and H (hydrogen) contained in a trace amount in a material such as steel. Relates to the device.
[0002]
[Prior art]
For example, as a quantitative analysis method for N and O contained in a small amount in steel, a combination of a melting extraction method in an inert gas, an infrared absorption method, and a thermal conductivity method is generally used. As a quantitative analysis method for C and S contained in a very small amount, a combination of an in-oxygen combustion method and an infrared absorption method is generally used.
[0003]
That is, the method combining the combustion method in the oxygen stream and the infrared ray absorption method burns steel as a sample while supplying oxygen gas into the heating furnace, and includes CO / CO ₂ and SO ₂ generated at that time. The combustion gas is analyzed with a non-dispersive infrared analyzer (NDIR), and the melting extraction method in the inert gas, the infrared absorption method, and the thermal conductivity method have a graphite crucible with a sample placed in a heating furnace. , and heated to melt the steel as a sample while supplying an inert gas, and analyzed in the NDIR for CO ₂ generated at that time are those analyzed by thermal conductivity method for N _2.
[0004]
By the way, in order to detect an element contained in a trace amount in a sample such as steel with high accuracy, it is necessary to remove in advance oil or dirt (hereinafter referred to as adhering matter) adhering to the surface of the sample. Such deposits include hydrocarbons, carbon dioxide gas, moisture, oxygen, and the like. For this reason, conventionally, the sample was subjected to pretreatment by electrolytic polishing, chemical polishing, or heating the sample at 400 ° C. to 600 ° C. for 10 minutes to remove deposits.
[0005]
[Problems to be solved by the invention]
However, in the pretreatment by the electrolytic polishing and chemical polishing, there are problems that a tool and chemicals for that purpose are required and a considerable amount of labor is required. Moreover, in the pretreatment by heating, there is a problem that a dedicated heating device is necessary. Furthermore, in any of the above pre-treatments, the sample that has been pre-treated must be placed in an extraction furnace such as an impulse furnace for the analysis. Although it is necessary to prevent it from adhering again, it is inevitable that the adhering material adheres again when the sample is handled.
[0006]
The present invention has been made in consideration of the above-mentioned matters, and its purpose is in a sample capable of accurately and quantitatively analyzing elements such as N, O, C, and S contained in a trace amount in a material such as steel. Elemental analyzer (hereinafter simply referred to as elemental analyzer).
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the elemental analysis apparatus according to the first aspect of the present invention heats and melts the sample in the graphite crucible while supplying the inert gas in the impulse furnace, and analyzes the gas extracted at that time in the gas analyzer. In the elemental analysis device for a sample in which at least one of oxygen, nitrogen and hydrogen in the sample is quantitatively analyzed, the upper part of the furnace body is connected to the sample introduction path into the graphite crucible. A pretreatment chamber opposed to the core and a sample inlet that is laterally deviated with respect to the sample introduction path, and a block body hermetically connected to the furnace body, and the pretreatment chamber of the block body And a position in which the sample receiving portion, which is held in an airtight state in a hole formed below the sample inlet and temporarily holds the sample, matches the sample inlet and a position that matches the pretreatment chamber. Can slide across, A sample supply device having a sample holder which is rotatable to allow the sample held in the sample receiving portion to be put into the graphite crucible from the sample feeding path at a position matched with the pretreatment chamber. In addition, a halogen lamp for irradiating light to the sample held in the sample receiving portion of the sample holder is provided in the pretreatment chamber, and the sample is placed in the graphite crucible by the rotation of the sample holder. Before being charged and melted by heating, the sample is irradiated with light from a halogen lamp, and the graphite crucible is energized to pre-treat the graphite crucible (claim 1).
[0008]
The elemental analyzer of the second invention burns the sample in the magnetic crucible while supplying the oxygen gas in the high-frequency heating furnace, analyzes the gas generated at that time in the gas analysis unit, and analyzes the carbon in the sample. In the elemental analysis apparatus for a sample in which at least one of sulfur and nitrogen is quantitatively analyzed, the upper part of the furnace body is concentrically opposed to the sample introduction path into the magnetic crucible A block body in which a sample insertion port that is laterally displaced with respect to the pretreatment chamber and the sample introduction path is formed and hermetically connected to the furnace body, and the pretreatment chamber and the sample insertion port of the block body A sample receiving portion that is held in an airtight state in a hole formed below and temporarily holds a sample is slidable between a position that matches the sample inlet and a position that matches the pretreatment chamber. And in the pretreatment chamber With the sample supply device is provided with a sample holder of the sample held in the sample receiving portion is rotatable in order to put into a porcelain crucible from the sample loading path at positions, the front A halogen lamp for irradiating light to the sample held in the sample receiving portion of the sample holder is provided in the processing chamber, and before the sample is put into the magnetic crucible by the rotation of the sample holder and burned. The sample is pretreated by irradiating light from a halogen lamp (claim 2).
[0009]
In the elemental analyzers of the first and second inventions, it is preferable that a vacuum pump capable of preliminarily placing the pretreatment chamber in a predetermined vacuum state is connected to the pretreatment chamber (claim). Item 3).
[0010]
In any of the above element analyzers, the deposits adhering to the sample surface can be surely removed in advance, so that the element contained only in a trace amount in the sample can be quantitatively analyzed with high accuracy.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. 1 to 3 show the first invention. First, FIG. 2 schematically shows the configuration of the elemental analysis apparatus according to the first invention. This elemental analysis apparatus quantitatively analyzes at least one of O, N, and H in a sample. It is configured.
[0012]
That is, in FIG. 2, reference numeral 1 is an impulse furnace as a melting extraction furnace, in which an inert gas such as helium gas is supplied, the sample is melted, and N and H are obtained by infrared absorption using O as CO. The gas flow path 2 connected to the subsequent stage of the impulse furnace 1 is provided with a dust filter 3 for removing dust contained in the gas generated in the impulse furnace 1, and then analyzed by the thermal conductivity method. A gas analyzer 4 is provided at the stage.
[0013]
Then, the the gas analyzer unit 4, the oxidation catalyst 6 for oxidizing non-dispersive infrared gas analyzer 5, CO gas for detecting CO gas contained in the gas extracted in impulse furnace 1 into CO _2, CO ₂ removal unit 7, dehydrator 8, line provided with thermal conductivity analyzer 9 for detecting N ₂ gas, room temperature oxidizer 10 for oxidizing CO gas to CO ₂ , CO ₂ remover 11, dehydration A vessel 12 and a line provided with a thermal conductivity analyzer 13 for detecting H ₂ gas are provided in parallel. The outputs of the non-dispersive infrared gas analyzer 5 and the thermal conductivity analyzers 9 and 13 are subjected to signal processing in a data processing unit (not shown) (for example, a microcomputer) to obtain O concentration, N concentration and H concentration. The configuration so far is not different from the conventional configuration of this type of elemental analyzer.
[0014]
Next, a characteristic configuration of the elemental analyzer according to the first invention will be described with reference to FIG. FIG. 1 schematically shows the structure of an impulse furnace 1 and the vicinity thereof. In this figure, reference numeral 14 denotes a furnace body, and an inner space 15 thereof has an upper electrode 16 and upper and lower electrodes 16. A lower electrode 18 is provided that moves and sandwiches the graphite crucible 17 together with the upper electrode 16. Reference numeral 19 denotes a sample input path formed in the upper part of the furnace body 14. Reference numeral 20 denotes an inert gas supply path for supplying an inert gas such as helium gas to the internal space 15, and reference numeral 21 denotes an inert gas cylinder.
[0015]
Reference numeral 22 denotes a sample supply device provided on the upper portion of the furnace body 14 and is configured as follows. That is, reference numeral 23 denotes a block body hermetically connected to the upper surface portion of the furnace body 14, a lower hole 24 communicating with the sample insertion path 19, a pretreatment chamber 25 concentric with the lower hole 24, and a lower hole A sample inlet 26 is formed that is laterally displaced with respect to 24 . A halogen lamp 27 and a lens 28 are provided above the pretreatment chamber 25 toward the lower sample insertion path 19. The halogen lamp 27 is formed, for example, by enclosing a halogen element or a halogen compound in a glass bulb. An opening 29 connected to a vacuum pump (not shown) is formed in the upper side portion of the pretreatment chamber 25.
[0016]
Reference numeral 30 denotes a horizontal cross section 31 formed horizontally in the block body 23 below the pretreatment chamber 25 and the sample insertion port 26 in the left-right direction (indicated by double arrows in the figure) while maintaining airtightness. slidable direction), and in a rotatable cylindrical sample holder, a sample receiving portion 33 for temporarily holding the sample 32. Reference numeral 34 denotes an operation knob provided at one end of the sample holder 30.
[0017]
The operation of the elemental analyzer having the above configuration will be described with reference to FIG.
(1) First, the graphite crucible 17 is placed on the lower electrode 18, the lower electrode 18 is further raised by a predetermined distance, and the graphite crucible 17 is sandwiched between the upper electrode 16 and the lower electrode 18. Then, slide the specimen holder 30 to the left, as shown in FIG. 3 (A), towards the sample receiving portion 33 on the upper surface, match the opening in the position of the sample inlet 26. In this state, steel as the sample 32 is put into the sample receiving portion 33 through the sample insertion port 26.
[0018]
(2) Next, the sample holder 30 is slid rightward so that the sample receiving portion 33 holding the sample 32 is aligned with the position of the pretreatment chamber 25 as shown in FIG. In this case, the pretreatment chamber 25 is previously set in a predetermined vacuum state by a vacuum pump. Then, as shown in FIG. 3B, the halogen lamp 27 is turned on, and the light (indicated by phantom lines in the figure) is applied to the sample 32 in the sample receiving portion 33 located in the pretreatment chamber 25. Irradiate directly . The halogen lamp 27 is set so that the temperature of the sample 32 is 400 to 600 ° C., and a predetermined pretreatment is performed by this light irradiation. This irradiation time may be about 1 to 3 minutes, for example. In parallel with the pretreatment of the sample 32, the graphite crucible 17 is energized through the upper electrode 16 and the lower electrode 18, and the graphite crucible 17 is baked. At this time, the energization current to the graphite crucible 17 is adjusted to be substantially the same as that during actual analysis. This blanking reduces the blank effect.
[0019]
(3) When the pretreatment of the sample 32 by irradiating the light of the halogen lamp 27 to the sample 32 and the baking of the graphite crucible 17 by energizing the graphite crucible 17 are finished, the sample holder 30 is rotated 180 ° at that position. Then, the sample 32 held in the sample receiving portion 33 is put into the graphite crucible 17. Since the graphite crucible 17 is energized through the upper electrode 16 and the lower electrode 18 while helium gas is supplied into the impulse furnace 1, the sample 32 in the graphite crucible 17 is heated and melted to extract the gas. is there.
[0020]
The extracted gas flows through the gas flow path 2 shown in FIG. 2, and CO gas is detected in the non-dispersive infrared gas analyzer 5 provided at the rear stage of the gas flow path 2 to analyze the thermal conductivity. in total 9, 13, _{N 2} gas, _{H 2} gas is detected. The outputs of the non-dispersive infrared gas analyzer 5 and the thermal conductivity analyzers 9 and 13 are subjected to signal processing in the data processing unit, and O concentration, N concentration and H concentration are obtained.
[0021]
As described above, in the elemental analyzer of the first invention, the sample 32 subjected to the analysis is irradiated with the light from the halogen lamp 27 before the analysis, and the surface of the sample 32 is 400 to 600 ° C. As a result, the deposit attached to the surface of the sample 32 can be completely removed during handling of the sample 32, and the influence on the measurement results of O, N, and H contained in the deposit can be avoided. it can. The graphite crucible 17 that accommodates the sample 32 and heats and melts it is baked before analysis, so avoid the influence on the measurement results of O, N, and H contained therein. Can do. Therefore, according to the first invention, it is possible to accurately measure O, N, and H in the sample 32 even if they are in a very small amount.
[0022]
In the above embodiment, the gas analyzer 4 is constituted by the non-dispersive infrared gas analyzer 5 and the thermal conductivity analyzers 9 and 13, but instead of this, a mass spectrometer is used. Also good. In this case, it is not necessary to use various analyzers, and it is not necessary to provide the oxidation catalyst 6, the CO ₂ removers 7 and 11, the dehydrators 8 and 12, the room temperature oxidizing agent 10, and the like.
[0023]
4 and 5 show the second invention. The elemental analysis apparatus according to the second invention is configured to quantitatively analyze at least one of C, S and N in the sample.
[0024]
That is, in FIG. 5, reference numeral 41 denotes a high-frequency heating furnace as a heating furnace, in which a sample is burned in a state where oxygen gas is supplied, and CO gas / CO ₂ gas and SO ₂ gas generated at that time are obtained by an infrared absorption method. In addition to the analysis, the NO ₂ gas is replaced with NO gas and analyzed by a chemiluminescence analysis method. The gas flow path 42 connected to the rear stage of the high-frequency heating furnace 41 has a CO gas extracted in the high-frequency heating furnace 41. A dust filter 43 and a dehumidifier 44 for removing oxidized dust and moisture contained in each of / CO ₂ gas, SO ₂ gas and NO ₂ gas are provided, and a gas analyzer 45 is provided at the subsequent stage.
[0025]
The gas analyzer 45 includes an oxidation catalyst 46 that oxidizes CO gas contained in the gas extracted in the high-frequency heating furnace 41 and converts it into CO ₂ gas, and a non-dispersive infrared gas for detecting CO _2. A line provided with an analyzer 47 in series, a line provided with a non-dispersive infrared gas analyzer 48 for detecting SO ₂ , a converter 49 for converting NO ₂ gas into NO gas, and NO gas are measured. is provided in parallel with the line provided with the NO _x meter 50 using the chemiluminescence gas analyzer (CLD) in series. The output of the non-dispersive infrared gas analyzer 47 and NO _x meter 50 is a signal processing in the data processing unit, not shown (for example, a microcomputer), C concentration, S concentration and the N concentration is obtained. The configuration so far is not different from the conventional configuration of this type of elemental analyzer.
[0026]
Next, a characteristic configuration of the elemental analyzer according to the present invention will be described with reference to FIG. FIG. 4 schematically shows the configuration of the high-frequency heating furnace 41 and the vicinity thereof. In this figure, 51 is a furnace body, and an inner space 52 has a crucible base 54 for holding a magnetic crucible 53. Is provided. The crucible base 54 is configured to move up and down the internal space 52 by a vertical movement mechanism (not shown) and to stop at a predetermined position. Reference numeral 55 denotes a high frequency coil wound around the upper part of the furnace body 51. Reference numeral 56 denotes a sample input path formed in the upper part of the furnace body 51. 57 is an oxygen gas supply path for supplying oxygen gas to the internal space 53, and 58 is an oxygen gas cylinder.
[0027]
The high-frequency heating furnace 41 configured as described above is provided with a sample supply device 22A at the top thereof, as in the impulse furnace 1 of the first invention. Since this sample supply device 22A has the same configuration as the sample supply device 22A in the first invention, the corresponding parts are denoted by the same reference numerals and description thereof is omitted.
[0028]
The operation of the elemental analyzer having the above configuration will be described. In this elemental analyzer, the magnetic crucible 53 is previously baked.
[0029]
(11) First, the magnetic crucible 53 is placed on the crucible base 54, the crucible base 54 is raised, and the magnetic crucible 53 is held at the position of the high-frequency coil 55. Then, slide the specimen holder 30 to the left, toward the sample receiving portion 33 on the upper surface, match the opening in the sample slot 26. In this state, steel as the sample 32 is put into the sample receiving portion 33 through the sample insertion port 26.
[0030]
(12) Next, the sample holder 30 is slid rightward so that the sample receiving portion 33 holding the sample 32 matches the position of the pretreatment chamber 25. In this case, the pretreatment chamber 25 is previously set in a predetermined vacuum state by a vacuum pump. Then, the halogen lamp 27 is turned on, and the light is irradiated to the sample 32 in the sample receiving portion 33 located in the pretreatment chamber 25 to perform a predetermined pretreatment. This irradiation time may be about 1 to 3 minutes.
[0031]
(13) When the pretreatment of the sample 32 by irradiation with light from a halogen lamp 27 to the sample 32 is completed, at that position, the sample holder 30 is rotated 180 °, the sample is held in the sample receiving portion 33 32 Into the graphite crucible 53. Then, in a state where oxygen gas is supplied into the high-frequency heating furnace 41, a high-frequency current is passed through the high-frequency coil 55 to heat the magnetic crucible 53, and the sample 32 accommodated therein is heated and melted to extract the gas. To do.
[0032]
The extracted gas flows through the gas flow path 42 shown in FIG. 5, and the dust filter 43 and the dehumidifier 44 provided in the gas flow path 42 remove oxidized dust and moisture, respectively. The analyzer 47 detects CO ₂ gas, the non-dispersive infrared gas analyzer 48 detects SO ₂ gas, and the NO _x meter 50 detects NO gas. The output of these non-dispersive infrared gas analyzer 47 and NO _x meter 50 is a signal processing in the data processing unit, C concentration, S concentration and the N concentration is obtained.
[0033]
As described above, in the elemental analyzer of the second invention, the sample 32 subjected to the analysis is irradiated with light from the halogen lamp 27 before the analysis, and the surface of the sample 32 is 400 to 600 ° C. As a result, the deposit attached to the surface of the sample 32 when the sample 32 is handled can be completely removed, and the influence on the measurement results of C, S and N contained in the deposit can be avoided. it can. The magnetic crucible 53 that accommodates the sample 32 and melts it is used as a separately baked one before analysis, so that the measurement results of C, S, and N contained in the crucible 53 are included. The impact can be avoided. Therefore, according to the above-described invention, C, S, and N in the sample 32 can be accurately measured even if they are in a very small amount.
[0034]
In the above embodiment, although the structure provided with such non-dispersive infrared gas analyzer 47 and NO _x meter 50 to the gas analyzer 45, instead of this, using a mass spectrometer Also good. In this case, it is not necessary to use various analyzers, and the oxidation catalyst 46 and the converter 49 need not be provided.
[0035]
[0036]
[0037]
[0039]
[0040]
[0041]
[0042]
[0043]
[0044]
[0045]
[0046]
[0047]
[0048]
[0050]
[0051]
[0052]
[0053]
【The invention's effect】
According to the elemental analysis apparatus of the present invention, a sample to be analyzed is irradiated with light from a halogen lamp before the analysis to reliably remove deposits adhering to the sample surface. It is possible to suppress variations in analysis results due to fluctuations in the amount of adhesion as much as possible, and elements such as N, O, C, S and H contained in trace amounts in various samples including steel Quantitative analysis can be performed with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of a main part of an elemental analysis apparatus according to a first invention.
FIG. 2 is a diagram schematically showing a configuration of an elemental analyzer according to the first invention.
FIG. 3 is a diagram for explaining the operation of the elemental analyzer of the first invention.
FIG. 4 is a diagram schematically showing a configuration of a main part of an elemental analyzer of the second invention.
FIG. 5 is a diagram schematically showing a configuration of an elemental analysis apparatus according to a second invention .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Impulse furnace, 4 ... Gas analysis part, 14 ... Furnace main body, 17 ... Graphite crucible, 19 ... Sample injection path, 22 ... Sample supply apparatus, 23 ... Block body, 25 ... Pretreatment chamber, 26 ... Sample injection port, 27 ... Halogen lamp, 30 ... Sample holder, 32 ... Sample, 33 ... Sample receiving part, 41 ... High-frequency heating furnace, 45 ... Gas analysis part, 53 ... Magnetic crucible .

Claims (3)

While supplying the inert gas in the impulse furnace, the sample in the graphite crucible is heated and melted, and the gas extracted at that time is analyzed in the gas analyzer, and at least one of oxygen, nitrogen and hydrogen in the sample is analyzed. In the elemental analysis device for a sample to be quantitatively analyzed, the upper part of the furnace body has a pretreatment chamber concentrically opposed to the sample charging path into the graphite crucible and a side to the sample charging path. A block is formed in an airtight manner in a block body formed in an airtight manner in the sample body and formed in a hole formed under the pretreatment chamber and the sample port in the block body. A position where the sample receiving portion for temporarily holding the sample can slide between a position where it is matched with the sample inlet and a position where it is matched with the pretreatment chamber, and where it is matched with the pretreatment chamber In the sample receiving part There is provided a sample supply device having a sample holder that is rotatable so that the held sample can be introduced into the graphite crucible from the sample introduction path, and the sample of the sample holder is provided in the pretreatment chamber. A halogen lamp for irradiating light to the sample held in the receiving part is provided, and before the sample is put into the graphite crucible by the rotation of the sample holder and heated and melted, the sample is heated from the halogen lamp. An elemental analysis apparatus for a sample characterized in that a pretreatment for irradiating light and energizing a graphite crucible to burn the graphite crucible empty is performed . A sample in a magnetic crucible is burned while supplying oxygen gas in a high-frequency heating furnace, and the gas generated at that time is analyzed in a gas analyzer to determine at least one of carbon, sulfur and nitrogen in the sample. In the elemental analysis device in the sample to be analyzed, the upper part of the furnace main body has a pretreatment chamber concentrically opposed to the sample charging path into the magnetic crucible and a side to the sample charging path. A block is formed in an airtight manner in a block body formed in an airtight manner in the sample body and formed in a hole formed under the pretreatment chamber and the sample port in the block body. A position where the sample receiving portion for temporarily holding the sample can slide between a position where it is matched with the sample inlet and a position where it is matched with the pretreatment chamber, and where it is matched with the pretreatment chamber Held by the sample holder A sample supply device having a sample holder that is rotatable so as to allow the sample to be introduced into the magnetic crucible from the sample introduction path, and the sample holder of the sample holder is provided in the pretreatment chamber. A halogen lamp for irradiating light to the sample held in the unit, and before the sample is put into the magnetic crucible by the rotation of the sample holder and burned, the light from the halogen lamp is applied to the sample. For elemental analysis in a sample, characterized in that a pretreatment for irradiation is performed . Wherein before the processing chamber, elemental analyzer in a sample according to claim 1 or 2 vacuum pump capable of a previously predetermined vacuum state pretreatment chamber is connected.

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