JPH0367168A - Analysis of trace carbon, sulfur, phosphorus in metallic sample and equipment therefor - Google Patents

Abstract

PURPOSE:To quickly quantify C, S, P in a metallic sample at ppm order by heating the surface of the metallic sample in gaseous hydrogen flow, introducing and concentrating the generated gaseous hydrides of C, S or P contained in the sample into a gas concentrator and them sending the concentrated gaseous hydrides to a gas analyzer by inert gas flow. CONSTITUTION:A sample base 2 is provided to the center of a cylindrical reaction chamber 1 and a top part is made of a quartz glass window 3. A gaseous hydrogen cylinder 5 is connected to the inlet side of the reaction chamber 1 via a pipeline 6. A heater 8 is arranged just above the reaction chamber 1. The surface of the sample is activated by heating this surface of the metallic sample S at high temp. The components of the sample S are allowed to react with gaseous hydrogen to produce gaseous hydrides. In other words, C in the metallic sample is allowed to react with hydrogen and changed into CH4, S is changed into H2S and P is changed into PH3. The generated gaseous hydrides are introduced into a gas concentrator 22 together with gaseous hydrogen flow and concentrated. The concentrated gaseous hydrides are carried to a gas analyzer 34 by inert gas and quantitatively analyzed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method and an apparatus for rapidly quantitatively analyzing characteristic carbon, sulfur, phosphorus, etc. in a metal sample.

The present invention is used for manufacturing process control analysis and quality control analysis in the steel industry or various non-ferrous metal manufacturing industries.

[Conventional technology] In order to manage operations such as gold crown refining and steelmaking processes, it is necessary to collect samples from molten metal, analyze them to ascertain the composition of gold ore as quickly as possible, and use the results to determine the age and treatment. It is necessary to take For example, in a steel manufacturing process, the time from sampling to obtaining analytical results is typically 5 to 6 minutes. Highly accurate and rapid analysis is also required for product verification. Among the components to be analyzed, carbon, sulfur, and phosphorus are important components in determining quality, especially in steel manufacturing.

For example, as a method for quantitatively analyzing trace carbon,
There is a "Method for Determining Carbon in Metals" disclosed in Publication No. 6-10251. In this method, a metal sample is heated in a hydrogen stream to generate and extract carbon in the sample as methane. The extracted methane is transported by a hydrogen stream and combusted together with hydrogen gas at the end of the pipe, and the carbon ionized by the combustion is detected and quantified. However, in this method, the metal sample must be made into particles of 40 to 50 μm, and it takes time to prepare the sample. In addition, the sample must be heated for a long time (1 hour in the example described in the above publication). Therefore, it has been difficult to feed back the analysis results to the manufacturing process for operational management. In addition, as a method for quantifying trace amounts of sulfur, time opening%j56-10252
There is a ``method for determining sulfur in metals'' disclosed in the publication.

This method also requires a long time to quantify sulfur.

To solve this problem, for example, there is a method for rapidly analyzing carbon and sulfur disclosed in Japanese Unexamined Patent Publication No. 157541/1983. In this analysis method, the surface of a molten metal is heated by spark discharge in an inert gas stream to evaporate and generate fine particles made of metal components. The generated fine particles are then pneumatically conveyed to an emission spectrometer using a transport tube, and carbon and sulfur are quantified by emission spectrometry.

Further, as another method for rapidly analyzing carbon and sulfur, there is a technique disclosed in Japanese Patent Application Laid-Open No. 61-65154. In this analysis method, the energy key of spark discharge, arc discharge, plasma arc discharge, or laser beam irradiation is applied to the analysis sample in an inert gas atmosphere containing oxygen gas. It excites the carbon and sulfur components present and converts them into gaseous oxides. Then, these oxide gases are introduced into a hydrogen flame, and the ionic current of the carbon component and/or the riL yellow component light intensity are measured to determine the content rate of each element in the sample.

[Problems to be Solved by the Invention] Recently, as products have become more sophisticated, high-grade steel materials containing trace amounts of high-purity metals, such as carbon, have been developed. For this reason, there is a demand for analyzing carbon and the like on the order of ppm. In addition, in order to use the analysis results for manufacturing process control and quality control, online analysis is required and the analysis must be completed in a short time.

However, in the rapid analysis method disclosed in JP-A-59-157541, fine particles are subjected to emission spectroscopic analysis in an inert gas stream, and high sensitivity cannot be obtained. Furthermore, in the rapid analysis method disclosed in JP-A No. 61-65154, since the arc is generated in an inert gas atmosphere mixed with oxygen gas, the arc becomes unstable and it is difficult to obtain high sensitivity similar to the above-mentioned rapid analysis method. I couldn't. Therefore, it has been impossible to rapidly quantify carbon and sulfur on the order of ppm using these limited rapid analysis methods.

Incidentally, spark emission spectroscopy requires a short analysis time but lacks sensitivity, while combustion-infrared absorption spectroscopy has a short sensitivity but has the problem of long analysis times.

Therefore, this invention aims to investigate carbon and sulfur in metal samples.

The purpose of this invention is to provide analytical power and an apparatus capable of rapidly quantifying phosphorus on a ppm scale.

[Means for Solving the Problems] The method of analyzing trace amounts of carbon, sulfur, and phosphorus in a metal sample according to the present invention heats the surface of the metal sample in a hydrogen gas stream to detect carbon, sulfur, or phosphorus gas in the sample. A gaseous hydride is generated, and the gaseous hydride is flowed into a scum concentrator to be concentrated, and at the same time, hydrogen gas is discharged and replaced with inert scum. Then, the concentrated gaseous hydride is sent to a waste analyzer using an inert gas stream, and the gaseous hydride is quantified. Trace carbon, sulfur, and phosphorus may all be analyzed simultaneously, or any one or two of these elements may be analyzed.

Step 4: To form a gas stream, hydrogen gas is supplied from an F1 hydrogen gas supply source to the sealed part passed through the gas concentrator. The hydrogen gas stream reacts with the heated sample surface to generate the amount of gaseous hydride necessary for analysis, and further converts the generated gaseous hydride into gas! ! The flow rate shall be sufficient to flow into the 1st retraction station.

The metal sample is in the form of a plate or block and is placed inside a closed chamber. In the steelmaking process, molten steel in a converter is sampled using a sub-lance, and a sample prepared by 3I is used in a disk with a diameter of 3 On+m, for example, using a sample preparation machine.

The method of heating the sample surface requires relatively high heating energy density because it is necessary to rapidly heat the sample surface to react with hydrogen gas and generate the amount of gaseous hydride required for analysis in a short time. There must be. For example, infrared heating, high frequency heating, etc. are used. The heating temperature varies depending on the composition and size of the sample, the required analysis time, etc.
The temperature is about 300 to 1000°C. In order to uniformly collect sample components, the heating area is desirably large, for example, about 100 to 70001112 mm.

Commonly used cold traps, a-condensation columns, and the like are used to condense the generated gaseous hydrides. As the adsorbent for the concentration column, Molexler Nob (registered trademark for synthetic fluorite), activated carbon, and others are used.

Argon, helium, nitrogen gas, etc. are used as an inert gas to replace hydrogen gas and send the concentrated gaseous hydride to the gas analyzer.

A gas analyzer for quantifying concentrated gaseous hydrides is
This device is equipped with a detector or an analytical device such as a semiconductor gas sensor, hydrogen flame ionization detection: atmosphere five-flame photometric detector, or inductively coupled plasma emission analyzer. A hydrogen flame ionization detector is used to detect carbon, and a flame photometric detector is used to detect sulfur and phosphorus.

Also, trace carbon in metal samples according to the present invention.

The sulfur-1-phosphorus analyzer implements the Kita method, and includes a sample chamber, a hydrogen gas supply source connected to the sample chamber, a heating device, a gas concentrator, an inert gas supply source, and a gas analyzer. It is equipped with

The sample chamber has a transmission window (j-shi), which accommodates a plate or block sample, and is airtight.The transmission window is made of quartz glass or other heat-resistant glass7, and the heating chamber is made of infrared rays. The lamp includes a lamp and a concave mirror.The infrared lamp is arranged inside the concave mirror so that the light from the infrared lamp is focused on the sample surface through the transmission window.The sample chamber is provided with a first trigonal punch. The gas concentrator is connected to the valve man 1-1, and the gas concentrator is connected to the outlet of the 13th Jf type valve.

An inert gas supply is connected to the other population of the first three-way switching valve. The gas concentrator is equipped with a second pressure rectangular switching block.
The gas analyzer is connected to the second three-way valve 1j, respectively. Additionally, one outlet ``1'' of the second rectangular switching valve is open to the public.

The hydrogen gas supply source and the inert gas supply source are, for example, a /F, an inner container, and a pressure vessel for storing these pressurized gases.
It consists of a stop valve, a flow rate adjustment valve, etc. attached to the l. Note that the gas concentrator and gas analyzer are the same as those explained in the invention of the above method.

[Function] By heating the fully bent sample surface to a high temperature, the sample surface IMi
is activated and the five metal sample components react with hydrogen gas to form a gaseous hydride. That is, carbon in a metal sample reacts with hydrogen to form methane ([114), and sulfur reacts with hydrogen sulfide ([114]).
H2S), and phosphorus becomes hydrogenated phosphorus (pi+, ). The composition of the mixed gas consisting of the generated gaseous hydride is as follows:
Substantially equal to the component composition of any analytical sample 1. ·stomach. The gaseous hydrides generated and the hydrogen gas stream also flow into a gas concentrator where they are concentrated. The concentrated gaseous hydride is transported to an inert gas analyzer and quantified. Since the gaseous hydride is mN,
Quantitative analysis with high precision.

In addition, in the apparatus of the present invention, the manual power of the infrared lamp is adjusted according to the size, surface condition, etc. of a metal sample in the form of a plate or block, and the surface of the sample is heated to a desired temperature in the required time. . 7JJII-: Square switching valve and No. 2E square switching valve are used to control the flow of gaseous hydride into the gas concentrator, exhaust hydrogen gas and replace it with inert gas, and inert gas flow. Perform operations such as feeding concentrated gaseous hydride to a gas analyzer.

[Example 1] Hereinafter, a case where trace amounts of carbon, sulfur, and phosphorus in a steel sample are simultaneously determined will be described as an example.

FIG. 1 schematically shows an example of a constant mastication analyzer for carrying out the method of the present invention.

A sample stage 2 is provided in the center of a cylindrical reaction chamber l,
The top is a quartz glass window 3. A hydrogen gas cylinder 5 is connected to the inlet side of the reaction chamber 1 via a pipe 6.

A heating device 8 is placed directly above the reaction chamber 1 . The heating device 8 includes a concave reflecting mirror 9 facing the quartz glass window 3 of the reaction chamber 1.
It is equipped with An infrared lamp IO is attached inside the reflector m9, and the output of the infrared lamp IO is controlled by a temperature controller 11. Infrared rays emitted from the infrared lamp IO pass through the quartz glass window 3 to the sample stage 2.
The upper analysis sample S is irradiated. At this time, in order to increase the heating energy density on the surface of the analysis sample, the infrared rays are
The light is focused by In this example, the infrared lamp lO
The power consumption '1 is I kw, and the irradiation area is room
II+2.

A dehumidifier +5 is provided on the piping 13 on the outlet side of the reaction chamber 1. The dehumidifier 15 absorbs moisture contained in the gas from the reaction chamber 1 using magnesium perchlorate.

A switching valve 17 is attached to the pipe 13.

A nitrogen gas cylinder 19 is connected to one of the inlet pipes 18 of the switching valve 17, and a gas concentrator 22 is connected to the outlet pipe 20 of the switching valve 17.

The gas concentrator 22 consists of a cold trap,
It includes a cooling tank 23 and a cooling pipe 24 inserted into the cooling tank 23. The cooling tank 23 is filled with liquid nitrogen 25.

Since the condensation temperature of methane, hydrogen sulfide and phosphorus hydride flowing into the cooling pipe 24 of the gas concentrator 22 is higher than that of liquid nitrogen, they are cooled by liquid nitrogen and condensed. On the other hand, since the condensation temperature of hydrogen gas is lower than that of liquid nitrogen, it passes through the cooling pipe 24 as it is. A sheathed heater 27 controlled by a temperature controller 26 is installed along the cooling pipe 24. The sheathed heater 27 is the cooling pipe 2
4 to vaporize the condensed gaseous hydride.

A switching valve 31 is provided on the outlet pipe 29 of the gas concentrator 22 . One outlet of the switching valve 31 is connected to a gas analyzer 34 via a pipe 32, and the other outlet is open to the atmosphere.

The gas analyzer 34 includes a chamber 35 and three SnO□ semiconductor gas sensors 36 arranged within the chamber. The three semiconductor gas sensors 36 are selected to have component selectivity for methane, hydrogen sulfide, and phosphorus hydride. The semiconductor gas sensor 35 is connected to a data processing section 37 including a signal processing circuit (not shown) for amplification, calculation, etc.

Here, a method for simultaneously analyzing trace amounts of carbon, sulfur, and phosphorus in the analysis sample S using the apparatus configured as described above will be described. The analysis sample S is obtained by preparing molten steel collected in a converter into a small disk shape with a diameter of 30 mm using a well-known sample preparation machine.

An analysis sample S is placed on the sample stage 2 of the reaction chamber 1.

Also, the cooling pipe 24 of the gas concentrator 22 passes from the nitrogen power supply 19 through the switching valve 17. Nitrogen gas is caused to flow into the switching valve 31 and the chamber 35 of the gas analyzer 34, and gas, atmosphere, etc. remaining in these devices and piping are discharged and removed.

Then, from the hydrogen gas cylinder 5 to the reaction chamber 1. Dehumidifier +5.
Switching valve 17. Hydrogen gas is caused to flow into the cooling pipe 24 and the switching valve 31. The surface of the analysis sample S is heated by the infrared lamp 10 while flowing hydrogen gas. In this example, the hydrogen gas flow rate is 50 tnl/+in
It is. Further, the heating temperature of the sample surface was 800° C., and the heating time was 60 seconds.

Next, the gaseous hydride ((:
H4, H2S, P, H) flow into the cooling pipe 24 of the gas concentrator 22 via the dehumidifier 15, where they are condensed.

Hydrogen gas is discharged from the switching valve 31 as described above.

When the gaseous hydride condenses, the switching valve 17 is activated to flow nitrogen gas from the nitrogen gas cylinder 19 into the cooling pipe 24, and the hydrogen gas remaining in the cooling pipe 24 and the piping before and after this is passed through the switching valve 31. Discharge. Once the hydrogen gas has been discharged, the switching valve 3I is switched to communicate the cooling pipe 24 with the chamber 35 of the gas analyzer 34, and the cooling tank is removed. Then, the cooling pipe 24 is heated by the sheathed heater 27 to vaporize the condensed hydride. The vaporized gaseous hydride flows into the chamber 35 of the gas analyzer 34 and is detected by the semiconductor gas sensor 36.

Depending on the above hydrogen gas flow rate and heating conditions, for example, approximately 0
．． 01 N111j! of methane gas is generated. Nitrogen gas flow rate after methane gas concentration is 100o+j2/wi
When n, the concentration of methane in nitrogen gas is approximately 1100
It becomes pp. The concentration detected by the semiconductor gas sensor 36 is even lower, and the concentration of 1ppm is a constant ([degrees] with a margin of 1-min. Therefore, the quantitative sensitivity of the powder method is extremely high, and the concentration of 1ppm is very low. can be determined sufficiently.The same applies to sulfur and phosphorus.According to the present invention, the time required for analysis is within about 1.5 minutes after setting the analysis sample S in the reaction chamber 1. I can do it.

As described above, using the semiconductor gas sensor 36 to detect carbon in a sample,
Although an example of simultaneously quantifying sulfur and phosphorus has been described, it is also possible to quantify one or both of these elements. Further, a detector or an analyzer other than a semiconductor gas sensor can also be used as the gas analyzer 34.

For example, these elements may be quantified using an optical emission spectrometer. When using inductively coupled plasma emission spectrometry (ICP), since ICP detects nitrogen gas, argon gas is used as the inert gas instead of the nitrogen gas. Furthermore, a flame ionization detector (FID) can also be used to quantify carbon. A hydrogen flame ionization detector is a detector commonly used in gas chromatographs, and uses a hydrogen flame as an excitation source to ionize an analytical component and measure the ion current. Since carbon dioxide cannot be measured with a flame ionization detector, a gas reduction device with a heated nickel catalyst is placed in front of the flame ionization detector. Carbon dioxide gas is reduced to methane and introduced into a hydrogen flame ionization detector, where it is detected with high sensitivity. Also, to perform quantitative analysis of sulfur or phosphorus.

A flame photometric detector (FPD) can also be used.

Flame photometric detectors are selectively sensitive to phosphorus and sulfur compounds, with sulfur around 400 nm;
Furthermore, phosphorus exhibits maximum emission intensity at a wavelength around 530 na+. Therefore, selection is made using an interference filter that passes through this wavelength range, and the intensity of each spectrum is measured using an optical multiplier. The sulfur or phosphorus content is calculated from the measured spectral intensity based on a calibration curve determined in advance using a steel standard sample.

Hereinafter, the explanation has been given using a steel sample as an example, but the present invention can also be applied to various non-ferrous metals, minerals, ceramics, etc. in addition to steel samples.

[Effects of the Invention] According to the present invention, although the elements to be analyzed are limited to carbon, sulfur, and phosphorus, these elements can be rapidly quantified on the order of ppm. In addition, since the main elements of carbon, sulfur, and phosphorus, which are the most important elements for quality evaluation of metals, are analyzed, it is extremely effective for operational management of metal refining and manufacturing processes.

[Brief explanation of drawings]

FIG. 1 is an apparatus configuration diagram schematically showing an example of an apparatus for carrying out the method of the present invention. DESCRIPTION OF SYMBOLS 1... Reaction chamber, 5... Hydrogen gas cylinder, 8... Heating device, 9... Reflector, IO... Infrared lamp 51
5... Dehumidifier, 17... Switching valve, 19... Nitrogen gas cylinder, 22... Gas concentrator, 24... Cooling pipe, 25... Liquid nitrogen, 31... Switching valve, 34・
...Gas analyzer, 36...Semiconductor gas sensor, 37
...Data processing section, S...Analysis sample.

Claims (1)

[Claims] 1. In a method of gasifying and analyzing components in a metal sample in a closed system, the surface of the metal sample is heated in a hydrogen gas stream to remove carbon, sulfur, or phosphorus in the gaseous state of the sample. Generate hydride, flow the gaseous hydride into a gas concentrator and concentrate it, exhaust the hydrogen gas and replace it with an inert gas, and send the concentrated gaseous hydride to a gas analyzer using an inert gas stream. A method for analyzing trace amounts of carbon, sulfur, and phosphorus in metal samples, which is characterized by quantifying gaseous hydrides. 2. A sample chamber having a transmission window and containing a plate or block-shaped sample, a hydrogen gas supply source connected to the sample chamber, an infrared lamp, and a concave mirror that focuses light from the infrared lamp onto the sample surface through the transmission window. a gas concentrator connected to the sample chamber via a first three-way switching valve, an inert gas supply connected to the other inlet of the first three-way switching valve, and one outlet. An apparatus for analyzing trace amounts of carbon, sulfur, and phosphorus in a metal sample, comprising a gas analyzer connected to the gas concentrator through a second three-way switching valve open to the atmosphere.