JPS63243871A - Method and instrument for direct analysis of molten metal by vertically movable type formation of fine particle by ultrasonic oscillation - Google Patents

Abstract

PURPOSE:To permit quick and direct analysis of various kinds of components by inserting a horn for ultrasonic oscillation into a molten metal and carrying the fine particles of the molten metal formed by the ultrasonic oscillation to an emission spectrochemical analysis instrument by inert gaseous flow. CONSTITUTION:The horn 6 is immediately heated to the temp. of a molten steel 2 and an ultrasonic oscillator 3 is operated when a probe 1 for forming fine particles is immersed into the molten steel 2. The ultrasonic oscillation generated from the oscillator 4 is transmitted via a transmission bar 5 to the horn 6 and a small amt. of the molten steel sticking to the surface of the horn 6 is splahed to form the fine particles. The fine particles of the molten steel are carried from a discharge port 15 of a fine particle forming chamber 23 through a transport pipe 8 by the inert gas supplied from an inert gas introducing pipe 7 to the plasma emission spectrochemical analysis instrument 11. The fine particles introduced into a plasma torch 20 are excited by a plasma flame 12 to emit light and the emission spectra thereof are spectrally split. The emission intensities of the respective elements are simultaneously measured by a photomultiplier 21 and the contents of the respective elements in the steel are determined by a data processor 22.

Description

Detailed Description of the Invention (Industrial Application Field 1) The present invention involves inserting a horn for ultrasonic oscillation into molten metal and placing fine particles of molten metal generated by ultrasonic imaging at a remote location. The present invention relates to a method and apparatus for analyzing the content of various components in molten metal in real time online by transporting the molten metal by an inert gas stream to an optical emission spectrometer having a plasma excitation source.

To manage operations such as metal refining and steel manufacturing processes, it is necessary to analyze as quickly as possible to understand the component content, and take appropriate action based on the results.

As described above, the present invention is a technology for directly analyzing molten metal, and is used in the fields of manufacturing process control analysis and quality control analysis in the steel industry, non-ferrous metal manufacturing industry, and the like.

(Prior art J) In the manufacturing process control analysis in the metal manufacturing industry, e-emission spectroscopy, which targets block samples obtained by sampling and solidifying molten metal, is often used. However,
In recent years, especially in the steel industry, online real-time technology has been used to directly target molten metals such as KX iron and iron, as well as faster manufacturing process control or operational control of new manufacturing processes such as multi-stage refining steelmaking. There is a strong demand for the development of analytical methods.

For the above-mentioned purposes, a method has been developed in which molten metal is pulverized using a special atomizer using Ar gas and then subjected to emission spectroscopic analysis (BISRA Annual Report Near 8 (19663, 65, 78 (1967), 35 (19
Various methods such as 687 have been studied. However, none of these methods have ever been actually put into practical use at manufacturing sites, and have only been attempted on a laboratory scale. The present inventors have also applied a method of performing emission spectroscopic analysis by irradiating molten metal with electrical discharge such as plasma arc or spark, or laser beam, etc., to evaporate fine particles representative of the composition of molten metal (Japanese Patent Laid-Open No. 1983-1993). No. 104152.

Invented JP-A No. 59-157541 J1 and a method of generating fine particles of molten metal by blowing inert gas and performing emission spectroscopic analysis (% JP-A No. 60-219538).
I just applied.

These inventions require a constant distance between the molten metal surface and the heating source device such as the tip of a spark discharge electrode, and are effective when the molten metal level fluctuates relatively slowly, but when the molten metal level fluctuates rapidly. In some cases, various measures must be taken to suppress fluctuations.

(Problem to be solved by the invention J) In developing a more practical direct analysis device for molten metal at actual manufacturing sites, we must take into consideration the fact that manufacturing sites have very poor measurement environments such as high temperatures, vibrations, and dust. Therefore, precision measurement equipment such as spectrometers and detectors that can cause trouble under adverse measurement environments must be installed in a building away from the location where molten metal is present. It is possible to evaporate the fine particles by applying external energy such as electric discharge, but if possible, the fine particles should be generated from the high-temperature molten metal itself by a simple physical method such as pulverization, and the fine particles can be collected and transported. It is preferable to do it in a simple way.

Under these circumstances, the present invention aims at online real-time analysis in manufacturing process control analysis of molten metal.
A practical analytical method for easily and quickly analyzing various components contained in molten metal by generating fine particles from molten metal by physical means and transporting them by an inert gas flow to an emission spectrometer having a plasma excitation source. It provides equipment.

(Means for Solving the Problems J) The present invention is characterized in that when producing fine particles from molten metal by a physical method, ultrasonic irradiation is employed as the method.

That is, in the present invention, first, the horn connected to the ultrasonic vibrator is immersed in the high-melt metal collected in the probe, and the horn is pulled up while applying ultrasonic waves, and the horn is immersed again. Fine particles are generated by scattering molten metal.

Next, the fine particles are transported and introduced into a plasma emission spectrometer using an inert gas stream, and the spectrum of the excited and emitted light is analyzed spectroscopically. The components contained in molten metal are determined online in real time using an analytical method and apparatus based on these principles.

(Example) The second structure of the present invention will be described based on examples of the apparatus for implementing the present invention and examples of analysis results shown in FIGS. 1 to 5.

FIG. 1 is an explanatory diagram of the entire system of nine examples of the present invention, including a plasma emission analysis section for the generated fine particles. FIGS. Figure 5 shows explanatory diagrams of the analysis results. These figures show an example in which the molten metal is molten steel in a processing ladle in a steelmaking process.

The device according to the example of the present invention has an ultrasonic transducer 4 and a WI@2
A particulate generation probe 1 immersed therein and a particulate transport pipe 8
It is mainly composed of a high-frequency coupled plasma emission spectrometer 11 connected through a

The particle-generating probe is made of a refractory material that has excellent high-temperature corrosion resistance and heat shock resistance, such as silicon carbide thread.

It is a cylinder made of alumina-carbon based refractory material, with an ultrasonic transmission rod 51r made of metal etc. installed at the center of the upper part, an inert gas outlet 13 such as Ar gas for transporting fine particles on the lower inner wall, and an inert gas outlet 13 for transporting fine particles at the upper part. A discharge port 15 is attached, and the inside is hollow to take in molten steel. Therefore, when the particle generation probe 1 is immersed in the molten steel 2, it becomes a closed container having a space for the particle generation chamber 23 inside. The ultrasonic transmission rod 5 is also attached to the probe 1 in a sealed state by using an O-ring T7 or the like. An ultrasonic oscillator 4 is coupled to the upper part of the transmission rod 5 via a cone, and the ultrasonic oscillator 3 is connected to the oscillator 4 by a cable 24. A shielding plate 16 is provided below the vibrator 4 to prevent heat radiation from the molten steel 2, and air is further blown around the vibrator 4 for cooling.

On the other hand, a horn 6 immersed in the molten steel 2 is located at the bottom of the transmission rod 5.
are connected by screwing. The horn is made of a material that has little corrosion resistance against molten steel and is resistant to heat shock, but is dense and allows ultrasonic waves to easily propagate, such as Zr-Mo-0 ceramics. However, when the molten metal has a low melting point, such as aluminum, tin, or lead, the horn material is preferably a metal such as stainless steel.

When the probe 1 is immersed in the molten steel 2, the horn 6, which has a much smaller volume than the volume of the high temperature molten steel of around 1600° C. contained in the probe, is immediately heated to the molten steel temperature. Once Ho/6 is heated, ultrasonic oscillator 3
The horn 6 is raised from the surface of the molten steel while applying ultrasonic waves.

Ultrasonic vibrations generated from the vibrator 4 are transmitted to the horn 6 via the transmission rod. A small amount of molten steel remaining on the surface of the horn 6 is scattered by the action of the ultrasonic waves and becomes fine particles. It is appropriate for the horn 6 to be made of a material having the above-mentioned characteristics, but a material with good wettability is more suitable for the purpose of leaving a thin film on the entire surface of the melting metal horn 6.

Forming irregularities such as shallow grooves on the horn surface in order to leave molten metal on the horn surface further improves the efficiency of generating fine particles. Even when the horn 6 is brought into contact with the surface of the molten steel 2 or immersed in the molten steel, fine particles of molten steel are generated from the contact valve surface between the horn surface and the molten steel. but,
Since the position of the molten steel surface fluctuates, it is actually difficult to bring the tip of the horn into stable contact with the molten steel surface.If the horn tip is immersed in the molten steel, the particle generation efficiency decreases.

Therefore, while moving the horn 6 up near the surface of the molten metal,
Alternatively, the most effective method is to generate fine particles using ultrasonic waves while moving up and down.

In FIG. 2, the ultrasonic transmission rod 5 is fixed to the particle generation probe 1, the probe 1 held on the particle generation device holding stand 25 is moved up and down by the probe lifting device 26, and the horn 6 is immersed in the molten steel 2. , then when performing the pull-up operation, all the following are shown.

In Fig. 3, the ultrasonic transmission rod 5 is sealed to the particle generation probe 1 with an O-ring 17 and attached with a vertically movable mechanism, the probe remains immersed in the molten steel, and a holder that holds the vibrator 4 is attached. A method is shown in which an ultrasonic horn elevating device 27 attached to a stand 25 is used to move the horn 6 up and down, such as lifting it out of the molten steel.

In order to transport the generated fc molten steel fine particles to the analyzer 11, the fine particle generation chamber 23 of the probe 1 is supplied with an inert gas for transporting the fine particles through the inert gas introduction pipe 7. In addition to Ar, N2, He, and the like are suitable for the inert gas. The type of gas is regulated in terms of the stability of the plasma flame 12 of the analyzer 11, but plasma flames that use air are currently being developed, and if this becomes possible, it will be possible to use air instead of inert gas. It may be used, and the fine particles become oxides, but there is no problem. However, when the horn 6 is oxidized, the natural frequency of the horn 6 changes and it becomes difficult to resonate, so it is necessary to select a material that is difficult to oxidize for the horn or to devise a tuning mechanism for the ultrasonic oscillator.

The blown inert gas passes through the porous brick 14 as shown in FIGS. 2 and 3, and is discharged as small bubbles from the inner wall of the probe 1 into the molten steel 2, thereby stirring the molten steel taken into the probe 1. It can be done. However, since the main purpose of introducing this inert gas is to transport fine particles, the discharge port 13 does not necessarily have to be located below the surface of the molten steel 25. A case is shown in which the ultrasonic transmission rod 5 and the horn 6 are provided inside, and the discharge port 13 is provided at the lower end of the horn 6. According to this method, there is no need to provide an introduction tube to the refractory probe 1, and the probe can be manufactured easily. In addition, the ultrasonic transmission rod 5 is heated due to heat conduction of molten steel and requires some kind of cooling.1. Blowing also has the advantage of being able to obtain the cooling effect of inert gas.

Fine particles of molten steel naturally evaporate from the surface of the molten steel due to the high heat of the molten steel itself. This amount of evaporation is much smaller than the amount of fine particles generated by physical methods such as ultrasonic vibration. 1! When fine particles are generated from molten metal by evaporation, selective evaporation based on the vapor pressure of each element is a problem and is directly affected by changes in the temperature of the molten metal.

This problem is particularly serious in natural evaporation, but even when fine particles are evaporated in a superheated state by providing high heat using external energy such as a plasma arc that can obtain extremely high temperatures, this problem cannot be completely resolved. The best way to avoid this problem of selective evaporation is not to generate fine particles through evaporation, but to pulverize the molten steel itself by a physical method to generate fine particles.

Furthermore, since the purpose of the present invention is quantitative analysis of each element in molten metal, the generated fine particles must be so fine that they can be easily and stably excited to emit light in plasma emission spectrometry. .

The present invention has conducted various studies on these points, and has developed molten steel 2.
A new method has been discovered for generating fine particles of molten steel from the surface of the molten steel by applying ultrasonic waves to the surface of the molten steel.

The fine particles of molten steel generated by ultrasonic irradiation have a diameter of approximately 1
They are fine particles of 0 μm or less and have a narrow particle size distribution, making them suitable for plasma emission spectroscopic analysis.

The G steel particles thus generated are transported from the particle outlet 15 provided at the upper part of the particle generation chamber 23 to the plasma emission spectrometer 11 via the particle transfer pipe 8. The transport pipe 8 is made of a stainless steel pipe or the like, and is preferably provided with a heating device ts' to prevent fine particles from adhering to the inner wall of the transport pipe 8 due to cooling.

The fine particles are sent into the carrier gas distributor 9 from the carrier pipe outlet at the end of the carrier pipe 8 . If the flow rate of the inert gas that transports the particles is the same as the flow rate introduced into the plasma torch 20, the carrier gas distributor 9 is not necessary. However, although the flow rate for introducing particulates into the plasma flame 12 is usually about 1 t/min, the flow rate for transporting particulates through the transport pipe 8 may be higher than this in order to shorten the transport time. In such a case, the valve 19f at the bottom of the gas distributor is adjusted to release part of the particle carrier gas to the outside of the system, and the required flow rate is introduced into the plasma torch 20 via the introduction pipe 10.

When a stainless steel pipe with an inner diameter of 4 ψ and a length of 40 m is used as the conveying pipe 8, and the Ar gas flow rate is 2 t/min,
The internal pressure in the particulate generation chamber 23 is approximately 150cmH20,
Although the hot water level fell by about 2 hours, the fine particles of Kogane reached the plasma torch 20 in a short time, and the spectral intensity of each element excited and emitted in the plasma flame 12 was measured by the photomultiplier tube 21. By performing integration over seconds, each element could be quantified with good reproducibility. A small amount of fine particles may remain on the inner wall of the transport tube, but after one analysis, which takes about 30 seconds, is completed, Ar gas is introduced into the transport pipe 8 at a flow rate of 5 to 10 t/min.
A method was adopted to remove residual fine particles by blowing into the tank.

Next, the Ar gas flow rate was increased to 10~2017 m1n, the molten steel in the particle generation chamber 23 was removed from the same chamber, and the flow rate was increased to 1~2017 m1n.
By returning to the normal state of 2 t/min, new molten steel 2 in the ladle can be taken into the production chamber 23.

With such a method, online analysis of the refining process of molten steel in the processing pot can be easily performed.

The fine particles introduced into the plasma torch 20 are excited by the high heat of the plasma flame 12 and emit light.The emission spectrum is separated, and the emission intensity of each element is simultaneously measured by the photomultiplier tube 21 set at each wavelength position. Simultaneous and rapid analysis of multiple elements in a substance can be performed.

In order to avoid being affected by slight fluctuations in the amount of 6 steel fine particles produced by ultrasonic irradiation, the luminescence intensity of each element was determined based on the luminescence intensity of iron, such as by taking the ratio to the luminescence intensity of iron. It is appropriate to adopt a correction calculation based on the following. Such calculations are performed by the data processing device 22, and the content of each element in the steel is determined. According to the present invention, C, P, contained in molten steel,
S, Si, Mn.

Simultaneous analysis of most elements such as Ni, Cr, and other elements except O, N, and H gas components could be performed. The present invention can also adequately analyze high melting point metals such as Ti, V, and W, which are difficult to evaporate using methods that generate fine particles by careful evaporation.

As the analyzer, an optical emission spectrometer having a plasma excitation source that can quantify multiple elements simultaneously and quickly and with high precision is suitable. At present, Ar is highly accurate and easy to handle.
A high-frequency inductively coupled plasma emission spectrometer using plasma is optimal.

An example will be described in which the present invention is implemented using the apparatus shown in FIG. 1 during vacuum degassing treatment in a steel manufacturing process.

The particulate generation probe 1 and the horn 6 are heated in advance in a heating furnace with a set of gas nozzles, an iron cap is attached to the lower end of the probe, and the probe 1 is inserted into the processing pot using the probe lifting device 26 that holds the probe 1. do. Immediately after passing through the slag layer and immersing the probe in molten steel, the cap dissolves and the +g steel 2 enters into the interior of the probe 1, excluding the slag. This operation is performed by introducing Ar gas into the inert gas introduction pipe 7.
Performed with ventilation at a flow rate of 1 t/min from
About 30 seconds after immersing the probe 141 in the steel, the lower part of the probe 1, the horn 6, etc. are preheated, and the particulate generation chamber 23 is heated.
The interior is also reliably made into an Ar atmosphere, and preparations for the generation of fine particles are completed.

Next, the ultrasonic oscillator 3 is activated to transmit the ultrasonic waves generated by the ultrasonic vibrator 4 to the transmission rod 5, and the horn 6, which has about half its total length immersed in the molten steel, generates ultrasonic waves at maximum output. let At the same time, the probe elevating device 26 was activated, and the horn 6 was repeatedly moved up and down so that it moved in and out of the m-steel interface. It is thought that when the horn is pulled up from the common steel surface, the molten steel remaining on the surface of the horn 6 is scattered by the ultrasonic waves generated from the horn, producing fine particles. Since the amount of fine particles produced increases when irregularities are formed on the horn surface, it is considered that molten steel fine particles are also generated from the horn surface.

The generated molten steel fine particles were transported to a plasma emission spectrometer 11 located 50 m away using a stainless steel tube with an inner diameter of 4 Wψ by a blown Ar gas stream.

At vacuum degassing processing sites, it is not possible to install a spectroscopic analyzer, which is a precision measurement device, near the location where molten steel exists due to the poor measurement environment such as high temperature, dust, and photography. It has the feature that it can be transported over long distances and then analyzed, making it particularly suitable for such purposes.

An example of the results of analyzing an in-gun in an m-steel under the above conditions is shown in Figure 5. Figure 5 shows Mn from the fcMn emission intensity and Fe emission intensity measured by the present invention during vacuum degassing treatment of various steel types such as thick plates and thin plates.
/F6 intensity ratio is calculated, the value is plotted on the QY axis, and the Mn analysis value obtained by the conventional method of spark emission spectrometry of nine samples sampled and solidified at the same time is plotted on the X axis.

In this way, there is a very good correlation between the two, and it can be seen that the present invention can be put to practical use in the same way as the conventional method, and there is no need to sample molten steel as in the conventional method. There was no need for transportation to an analysis center via conduit, or for pretreatment such as cutting or polishing. In the conventional method, the total analysis time usually took 4 to 5 minutes, but with the present invention, the initial analysis could be performed within 2 minutes, and furthermore, analysis values could be obtained continuously thereafter.

Figure 5 shows the results of Mn analysis, but the present invention can analyze multiple elements simultaneously, including P, S, and Si, which are required for steel analysis.
, At, Ti, Ni, Cr, and many other components could be analyzed with good accuracy, almost the same as the Mn analysis.

(Effects of the Invention J As explained above and as follows, the present invention enables quick analysis of components contained in molten metal samples without the complicated pretreatment operations such as sampling, cooling solidification, cutting, and polishing that have been carried out in the past when analyzing components contained in molten metal samples. Moreover, it can be directly analyzed with high precision, making it extremely effective for quality control and operational management in metal refining and steelmaking processes.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the apparatus according to the present invention, Figs. FIG. 1... Fine particle generation probe, 2... Molten steel, 3...
Ultrasonic oscillator, 4... Ultrasonic camera, 5... Ultrasonic transmission rod, 6... Horn, 7... Inert gas introduction pipe,
8... Particulate transport pipe, 9... Carrier gas distributor, 11
...High frequency inductively coupled plasma emission spectrometer, 20
...Plasma torch, 23...Particle generation chamber, 25
. . . Particle generation device holding stand, 26 . . . Particle generation probe lifting device, 27 . . . Ultrasonic horn lifting device. Agent: Patent attorney Masaaki Akizawa and 1 talented figure 73 figure Otsu figure 5 figure Mn (%)

Claims (7)

[Claims] (1) A horn connected to an ultrasonic vibrator is inserted while oscillating into the molten metal collected in the probe whose bottom opening is closed by the molten metal, and then the molten metal is removed. During the vertical movement of the lifting horn, the molten metal adhering to the horn surface is scattered and generated as fine particles by ultrasonic vibration, and the generated fine particles of molten metal are discharged from the top of the probe by an inert gas blown into the probe, creating a plasma. Molten metal is transported and introduced into an emission spectrometer to measure the luminescence intensity of each element in the particles and determine the concentration of each element contained in the molten metal. Direct analysis method. (2) The vertical movement according to claim 1, characterized in that the molten metal adhering to the surface of the horn is turned into fine particles by ultrasonic vibration while repeating the vertical movement of lifting the horn out of the molten metal and dipping it again. A method for direct analysis of molten metal by ultrasonic vibration particle generation. (3) A method for direct analysis of molten metal by vertically movable ultrasonic vibration particle generation according to claim 1 or 2, which uses a horn with an uneven surface. (4) A particulate generation probe that has an inert gas inlet on the lower inner wall and a particulate discharge port on the upper part, the bottom part of which is immersed in molten metal to create a sealed state, and a lifting mechanism that can move up and down. a particle generation device in which an ultrasonic transmission rod is attached to the upper part of the particle generation probe, the ultrasonic transducer having an ultrasonic transducer connected to a sonic oscillator and a cable connected to the upper part and a horn immersed in molten metal in the lower part; A direct analysis device for molten metal by vertically movable ultrasonic vibration particle generation, comprising a plasma emission spectrometer to which the particle discharge port is connected via a conveying pipe. (5) An inert gas supply port is provided in the ultrasonic transmission rod, an inert gas passage hole is passed through the transmission rod, and an inert gas is supplied to a horn connected to the tip of the transmission rod and immersed in the molten metal. Claim 4 characterized in that an introduction port is provided.
A device for directly analyzing molten metal by vertically movable ultrasonic vibration generating fine particles as described in 2. (6) An inert gas inlet is provided on the lower inner wall and a particulate discharge port is provided at the upper part, and the particulate generation probe, whose bottom part is immersed in molten metal to form a sealed state, is equipped with an elevating mechanism that can move up and down. A direct analysis device for molten metal by vertically movable ultrasonic vibration particle generation according to claim 4. (7) A direct analysis device for molten metal by vertically movable ultrasonic vibration particle generation according to claim 4 or 5, which uses a horn having an uneven surface.