JPH0513259B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for measuring the amount of manganese in molten metal, and more specifically, the amount of manganese in molten metal can be analyzed in a short time and by simply holding the probe immersed. Concerning how it can be done accurately.

[Conventional technology]

For example, in the steelmaking process, accurately and quickly detecting and measuring the content of elements such as manganese, silicon, carbon, sulfur, and phosphorus in molten steel is important in the refining process to remove these elements, or in determining their amounts. This is an extremely important concern in processes where additions are made to maintain a constant amount, and performing this work efficiently is an essential condition for shortening the overall steelmaking process and reducing costs. . or,
This situation is similar, for example, in the aluminum refining process, and measuring the content of specific elements in various other molten metals is also an important issue.

Conventionally, methods for measuring the amount of elements contained in molten metal include the oxygen concentration measurement method, which involves attaching an oxygen sensor using a solid electrolyte to the tip of a probe, and the method of measuring molten steel by immersing a sublance in a converter. A known carbon content measurement method is to measure the solidification temperature of the sampled molten steel.

In addition, as a method for measuring the amount of silicon, a space opened to the outside is provided at the tip of the main body of the device, and two
Two electrodes are provided as detection ends, and one electrode is associated with a temperature lowering means so as to create a temperature difference between the two electrodes, and the thermoelectromotive force generated between these two electrodes is measured. The applicant has filed an application for a thermoelectromotive force method for measuring the amount of silicon in the material. However, measurement using this thermoelectromotive force method was limited to measuring the amount of silicon in hot metal. This is because the thermoelectromotive force generated between a pair of electrodes immersed in hot metal with a temperature difference is almost determined by the silicon content, and the effect of the presence of other elements on the thermoelectromotive force is relative. However, when measuring the content of trace elements in general molten metal, the thermoelectromotive force generated between the two electrodes has multiple types of thermoelectromotive force values. Because the effects of elements are compounded, it is not possible to exclude the influence of elements other than the intended one, and especially when the number of carbons is unknown, the carbon content has a large effect on the thermoelectromotive force value, It was not possible to measure the content of the elements.

Therefore, this thermoelectromotive force method has never been used to measure the manganese content in the process of controlling the amount of ferromanganese or manganese ore added in the steelmaking process or in the aluminum refining process.
In particular, when measuring the amount of manganese in molten steel, the conventional physical or chemical analysis method of collecting a molten steel sample and cooling it has been followed.

[Problem that the invention seeks to solve]

However, the measurement of manganese content in molten metal was dependent on the above analytical method.
Not only does analysis take time, but the state of the molten metal changes from moment to moment, making it impossible to measure accurately and determining the appropriate amount of ferromanganese and manganese ore to be added. It was also considered inefficient.

[Means for solving problems]

The present invention was made to solve these problems, and it is possible to measure the amount of manganese in molten metal by applying the principle disclosed in the device for measuring the amount of silicon in molten metal that was previously filed by the same applicant. The purpose of this study is to provide a method for measuring

When a pair of electrodes with a temperature difference are placed in a molten iron alloy, the magnitude of the thermoelectromotive force generated between the two electrodes is determined by the amount of silicon among trace elements such as silicon, manganese, carbon, phosphorus, and sulfur. It is known that it depends largely on the content. This principle was used in the invention related to the earlier application by the present applicant, but the content of the above-mentioned trace elements other than silicon also changes into thermoelectromotive force, and the amount of change is not as large as that of silicon. However, it is still within a measurable range. It is also recognized that this change is not limited to molten iron alloys, but also occurs in other molten metals.

The present inventors believe that if the amount of silicon is unknown or changes, it is not possible to clearly distinguish and extract the influence of differences in the content of trace elements such as manganese on the thermoelectromotive force value, but the amount of silicon is known. In this case, the present invention was completed based on the idea that it is possible to clearly distinguish and extract the influence of differences in the content of trace elements such as manganese on the thermoelectromotive force value.

In other words, the present invention aims to measure the amount of manganese in molten metal in cases where silicon has almost no effect on thermoelectromotive force or whose degree of effect is being measured, such as during preliminary treatment in the steelmaking process. In the case of molten pig iron, it is used after the converter process, and in the case of ordinary pig iron and desulfurized pig iron, it is used after the converter has been desiliconized, that is, at the end of blowing and at the end of blowing, and after the converter process, and there is almost no silicon. It is used in situations where the amount does not change. In these steps, there is almost no change in the content of elements other than manganese and carbon, and deoxidation by adding ferromanganese is performed under these conditions. The deoxidation process must be carried out under strict control, and for this reason, in order to determine the amount of ferromanganese to be added,
It is extremely important to measure the amount of manganese in hot metal.

The method for measuring the amount of manganese in molten metal according to the present invention is for measuring the content of manganese as long as other components other than manganese and carbon do not change or the amount of change can be confirmed. If the conditions are satisfied, it can be used not only for measuring the amount of manganese in hot metal and molten steel, but also in ferroalloys. In order to more accurately measure the amount of manganese in such various molten metals, it is desirable that the exterior shape of the device, the electrode arrangement position, etc. be optimized for each molten metal.

The present invention was made based on the above idea. The gist of this method is to measure a molten metal whose content of elements other than manganese and carbon does not change or whose amount is known, and to immerse it in the molten metal that is the object to be measured. Provide at least two cavities on the tip side of the device body for introducing and solidifying molten metal,
One cavity is constructed from a mold with a larger cooling capacity on the base side than the opening side, and the thermoelectromotive force is measured in the high temperature side space formed on the opening side and the low temperature side space formed on the base side of the cavity. A sensing end for the metal to be measured is arranged to make this space a space for measuring thermoelectromotive force, and the other space is used as a space for measuring the solidification temperature by installing a thermocouple for measuring the solidification temperature. By one immersion operation, a sample is collected in the thermoelectromotive force measurement space and the coagulation temperature measurement space, and the thermoelectromotive force value of the sample collected in the thermoelectromotive force measurement space and the coagulation temperature measurement space are collected. The solidification temperature of the collected sample is measured, and the influence of the carbon content on the thermoelectromotive force value is calculated from the carbon content determined by the solidification temperature measurement method. It is characterized by specifying the manganese content.

[Example] Next, details of the present invention will be explained by referring to an example shown in the accompanying drawings.

What is shown in FIG. 1 is a sectional view showing an embodiment of the device used in the method for measuring the amount of manganese in molten metal according to the present invention, and FIG. 2 is an enlarged sectional view of the main part of the tip of the device. be.

The manganese amount measuring device 1 is constructed by fixing a cavity forming member 3 having a cooling capacity with heat-resistant cement 4 or the like inside the tip of an exterior tube 2 made of a paper tube, a refractory material, etc., and forming a cavity into which molten metal is introduced. 8 and on the other hand,
A cavity 21 into which molten metal is introduced is also formed behind the cavity 8. The space 8 is for providing a space for thermoelectromotive force measurement, and the space 21
is a space for measuring solidification temperature. The space 8 is a space for measuring elements whose content affects the thermoelectromotive force value, and the space 21 is a space for measuring elements whose content affects the solidification temperature. The present invention targets carbon in this space.

The cavity forming member 3 is manufactured by a mold, and as shown in the figure, is a cylindrical member having, for example, an opening 6 at the tip as a whole, and is made of a heat-resistant material such as iron, copper, or ceramic, either as it is or made of these materials. Among them, for example, materials such as copper and iron are made by coating the surface with an inorganic heat-resistant material. The mold constituting the cavity forming member 3 is provided with a cooling means 5 made of a thicker wall of the cavity forming member 3 at the bottom of the cavity, so that the cooling capacity on the cavity bottom side is increased compared to the opening 6 side. The opening side 6 is a high temperature side space, and the base 12 side is a low temperature side space.

The opening 6 is such that a cylindrical inflow pipe 7 made of, for example, ceramic is provided at the tip of the probe, and this inflow pipe 7 communicates between the cavity 8 and the outside through the opening 6 of the cavity forming member 3. This makes it possible to introduce molten metal from outside. This opening 6
The internal space 8 of the cavity forming member 3 is formed in a slightly reduced diameter state, and after the molten metal flowing from the inflow pipe 7 is introduced into the cavity 8 through the opening 6, the measuring device 1 is installed. Solidification in this portion is made quick so that the molten metal does not flow out from the opening 6 when pulled up from the molten metal.

In the figure, 15, 15 are thermocouples, the hot junction of one thermocouple is located in the low-temperature side space, and the hot junction of the other thermocouple is located in the high-temperature side space. It also serves as electrodes 9 and 10 as detection ends. Although not shown, it is also possible to arrange a dedicated electrode as an electrode for measuring thermoelectromotive force without also serving as a hot junction of a thermocouple.

Reference numeral 11 denotes a cap made of iron or the like that is fitted over the inlet pipe, and its thickness is set so that it will melt away after being immersed in the molten metal and passing through the slag. Reference numeral 12 denotes a base for fixing the electrodes 9 and 10, and lead wires from both the electrodes 9 and 10 are led out toward a connector 13 in the device through the base 12.

The space 21 provided behind the space 8 as a space for measuring thermoelectromotive force is used to measure the content of an element whose content affects the solidification temperature. A thermocouple 22 for measuring the solidification temperature is placed inside. The mutual arrangement relationship of the space 8 serving as the thermoelectromotive force measurement space and the space 21 serving as the solidification temperature measurement space is not limited to that shown in the figure, and other configurations may also be adopted.

Although 24 in the figure is a sample collection container 24 for spectroscopic emission analysis, this container can also be excluded.

The device 1 having such a configuration is used in the following manner. When the exterior tube 2 is gripped by a suitable mechanism and the device is immersed in the intended molten metal, the cap 11 at the tip will first melt away, and the molten metal will flow in from the inlet tube 7 and the cavity forming member 3 The liquid flows into the space 8 from the opening 6 of the thermoelectromotive force and fills the space 8 as a space for measuring thermoelectromotive force. The molten metal flowing in this state is cooled by the cavity forming member 3, and in particular, the space surrounded by the cooling means 5 formed by partially thickening the mold is rapidly cooled to a low temperature. A low temperature is quickly applied to the side electrode 9, and a predetermined temperature difference is applied to the high temperature side electrode 10 located on the opening side. Although it is possible to maintain a predetermined temperature difference between the low-temperature side electrode 9 and the high-temperature side electrode 10 even when the measuring device 1 is immersed in the molten metal, it is more preferable to It is desirable to withdraw the metal at the same time as it is filled.

The reason why it is preferable to lift the measuring device 1 from the molten metal is that in this way, the molten metal sampled is isolated from the molten metal in the furnace, which has a large heat capacity, and the influence of the heat of the molten metal in the furnace is also cut off. This is because it becomes easy to quickly provide a predetermined temperature difference between the low-temperature side electrode 9 and the high-temperature side electrode 10, and to maintain this temperature difference.

Then, the thermoelectromotive force generated between the low temperature side electrode 9 and the high temperature side electrode 10 to which a predetermined temperature difference is given in this way is measured.

In addition, when the molten metal is introduced into the cavity 8, the molten metal also flows into the cavity 21, which forms the space for solidification temperature measurement, from the opening formed by partially burning out the outer tube 2. The temperature change during the solidification process of the molten metal is observed by the solidification temperature measuring thermocouple 22.

In addition, the molten metal introduced into the cavity 8 is prevented from flowing out by the opening 6 whose diameter is smaller than the inner diameter of the cavity 8, and is quickly solidified at the opening 6, so that the molten metal does not flow into the molten metal. Even if the device is immediately pulled up after being immersed, there is no risk that the molten metal that has flowed into the device will leak out from the cavity 8.

Further, the reason why a large space is provided between the high temperature side electrode 10 and the opening 6 is to provide this space with a function as a sample collection container. That is, with such a configuration, after the molten metal introduced into the cavity 8 is solidified, if this solidified sample is taken out,
Since only a portion of the coagulated sample is contaminated with the electrode 10 as a foreign substance, most of the portion of the coagulated sample taken out can be used as a sampler for physical or chemical analysis.

Then, the carbon content is specified based on the solidification temperature curve obtained by the solidification temperature measurement thermocouple 22, and the electrodes 9 and 1 are
The amount of manganese in the molten metal is determined by processing the thermoelectromotive force generated during zero using the thermoelectromotive force method.

In particular, in this embodiment, since the hot junction of the temperature measuring thermocouples 15, 15 is given the function of the low temperature side electrode 9 and the high temperature side electrode 10 for thermoelectromotive force measurement, the presence of both electrodes 9, 10 Since the temperature difference between the two electrodes 9 and 10 can be monitored by measuring the temperature at the same position, it is possible to compensate for fluctuations in the temperature difference between the two electrodes, allowing for more accurate measurements. It becomes possible. In addition, in the diagram, there are three lead wires led out from each thermocouple, but from FIG. A two-wire structure as shown in FIG. 10 can also be used.

What is shown in FIG. 11 specifically shows the structure near the hot junction of this thermocouple.
Two parallel through holes 28, 28 are formed inside the 0, and thermocouple wires 27, 27 made of, for example, chromel/alumel wires are introduced into the through holes, and the tips of both wires 27, 27 are inserted. are melted and fixed as shown in the figure to form a hot junction 26. The hot junction 26 is partially or completely exposed and is held together with the wires 27 and 27 by, for example, heat-resistant insulating means 29, which is mounted with heat-resistant cement as shown in the figure. In addition to forming the thermocouple wires 27, 27, a method of covering the thermocouple wires 27, 27 with heat-resistant cement may be adopted as appropriate.
In this way, temperature measurement and thermoelectromotive force measurement for determining the amount of contained elements can be performed at the same position, so that the amount of contained elements can be measured with higher accuracy.

Figures 3 to 5 show other embodiments of the thermoelectromotive force measurement space, and whereas each of the previous embodiments had six openings on the tip side of the device. An opening 6 is provided on the side of the device to serve as an inlet for the molten metal sample, and a cooling member 5 with a large heat capacity is placed on the bottom side of the cavity 8, so that the opening 6 side is a high-temperature side space and the bottom side is a low-temperature side space. This is an example in which a low temperature side electrode 9 and a high temperature side electrode 10 are arranged in each space.

Moreover, what is shown in FIG. 6 is an example in which the previous embodiment and various other functions are combined. The metal side electrode 20 is embedded in refractory cement, etc., and the temperature of the molten metal is measured by the thermocouple 18 for measuring the temperature of molten metal for the oxygen concentration battery. The oxygen concentration in the molten metal can be measured using the molten metal side electrode 20.

FIG. 7 shows another embodiment, in which a washer or the like made of iron or ceramic is appropriately fitted into the cavity 21 serving as the space for measuring the solidification temperature, and the reduced diameter portion 2 is
3 is formed, and the speed of the molten alloy iron flowing into the space where the thermocouple 22 for solidification temperature measurement is arranged is adjusted appropriately due to the presence of the reduced diameter part 23, and a solidification curve suitable for the solidification temperature measurement is obtained. It is possible to obtain this.

What is shown in FIG. 8 is the above-described apparatus to which another sample collection container 24 for spectroscopic emission analysis is added. Although it is possible to use each space as a sample collection container in the apparatus shown in Figures 3 to 7, it is also possible to use a separate sample collection container as shown in Figures 8 and 1. This is more preferable because the structure of the sample collection container can be set so that the sample is in an ideal state.

FIG. 9 shows an embodiment in which a thermocouple 18 for measuring the temperature of molten metal is embedded in the tip of the apparatus shown in FIG. 7, thereby making it possible to simultaneously measure the temperature of the molten metal in addition to the above measurements. Furthermore, FIG. 10 shows an example in which a thermocouple-equipped oxygen concentration battery 25 is buried in place of the thermocouple for measuring the temperature of molten metal, making it possible to measure the oxygen concentration in addition to the above measurements. These Figures 9 and 1
It goes without saying that a sample collection container can be provided as appropriate in the embodiment shown in FIG. 2
It is not a problem to change the vertical relationship of the arrangement of the numbers 4 and 4.

As described above, the method for measuring the amount of manganese in molten metal according to the present invention uses both the thermoelectromotive force method and the solidification temperature measuring method. By subtracting the thermoelectromotive force value corresponding to the carbon content from the thermoelectromotive force value measured by the method, the amount of manganese in the molten metal can be measured. Not only the amount of manganese, but also the amount of manganese in general molten metal can be measured quickly and accurately by appropriately devising the exterior shape of the device, the electrode arrangement position, etc. Therefore, when measuring the carbon content is essential, for example when measuring the amount of manganese using the thermoelectromotive force method and the influence of the amount of carbon cannot be ignored, the data for calculating the amount of manganese can be obtained with a single measurement. Process control becomes more efficient. Conversely, when measuring the carbon content, by using the measured value of the manganese content, the influence of the manganese content on the solidification curve of molten steel can be removed, making it possible to measure the carbon content more accurately.

[Effects of the Invention] The method for measuring the amount of manganese in molten metal of the present invention is as follows:
We decided to use a measuring device that has a space for measuring thermoelectromotive force and a space for measuring solidification temperature, and simultaneously measure the amount of contained elements by thermoelectromotive force method and measure the amount of carbon by solidification temperature measuring method. When the target is a molten metal in which the content of other elements does not change or whose amounts are known, the carbon content determined by the solidification temperature measurement method should be taken into account in the results obtained by the thermoelectromotive force method. By doing this, it is possible to accurately measure the amount of manganese. Therefore, there is no need to collect a sample in a collection container and measure the amount of manganese as in the past, and it is possible to It is now possible to easily measure the amount of manganese by simply immersing it in the water, greatly reducing the time required for analysis.
The amount of manganese in the molten metal, which changes from moment to moment, can be accurately grasped.

Therefore, the present invention can be applied, for example, to pre-treated hot metal in the steelmaking process after the converter process, and in the case of ordinary pig iron or desulfurized pig iron, it can be applied after desiliconization in the converter, that is, at the final stage of blowing. It can be applied to processes after the blow-off, blow-off, and converter processes, and the amount of manganese in hot metal in these processes can be measured accurately and quickly. Therefore, it is possible to efficiently adjust the amount of ferromanganese and manganese ore added for deoxidation in these processes, and dynamic control stabilizes the product and improves the yield of ferromanganese and manganese ore. We also hope to improve this.

Furthermore, the present invention can be applied not only to molten steel but also to aluminum refining processes, etc., and it is also possible to measure the amount of elements contained in ferroalloys, so it can be used, for example, in the production of ferromanganese, which is the additive mentioned above.

Furthermore, the measuring device used in the present invention is of the immersion type, and the mold constituting the thermoelectromotive force measurement space has a larger cooling capacity on the base side than on the opening side.
The low-temperature side electrode, which is one of the detection ends, can be quickly brought to a low temperature state, and a predetermined temperature difference can be quickly given between it and the high-temperature side electrode, making it possible to measure the amount of elements using the thermoelectromotive force method. It can be done quickly, and as a result, the amount of manganese can be measured in a short time.

[Brief explanation of drawings]

The drawings show various embodiments of the measuring device used in the method for measuring the amount of manganese in molten metal of the present invention. FIG. 1 is a cross-sectional explanatory diagram of one embodiment of the measuring device, and FIG. Enlarged sectional view of the section, Figures 3 to 5
The figure is an explanatory diagram of another embodiment of a thermoelectromotive force measurement space with an opening provided on the side of the device, Figures 6 to 10 are explanatory diagrams of an embodiment of a device combining other measuring means, and Figure 11
The figure is an explanatory diagram showing the specific structure of the thermocouple, and FIG. 12 is an explanatory diagram showing the wiring state of the thermocouple. 1... Manganese amount measuring device, 2... Exterior tube, 3
...Vacancy forming member, 4...Cement, 5...Cooling means, 6...Opening, 7...Inflow pipe, 8...Vacancy,
9... Low temperature side electrode, 10... High temperature side electrode, 11...
...Cap, 12...Base, 13...Connector,
15... Thermocouple for temperature measurement, 18... Thermocouple for molten metal temperature measurement, 19... Oxygen concentration battery, 20... Molten metal side electrode for oxygen concentration battery, 21... Blank space, 22...
... Thermocouple for measuring solidification temperature, 23 ... Reduced diameter part, 24
... Sample collection container, 25 ... Oxygen concentration battery, 2
6, 26'... Hot junction, 27... Element wire, 28...
Through hole, 29... Insulating means, 30... Insulating tube.

Claims (1)

[Scope of Claims] 1. A molten metal whose content of elements other than manganese and carbon does not change or whose amount is known is set as a measurement object, and the molten metal is poured into the molten metal and immersed in the molten metal that is the object to be measured. At least two cavities for introducing and solidifying molten metal are provided on the tip side of the main body of the device, and one of the cavities is constructed from a mold whose cooling capacity is larger on the base side than on the opening side. Detection ends for measuring thermo-electromotive force are arranged in the high-temperature side space formed on the opening side and the low-temperature side space formed on the base side. The space is equipped with a thermocouple for measuring solidification temperature, and is used as a space for measuring solidification temperature, and samples are collected in the space for measuring thermoelectromotive force and the space for measuring solidification temperature by one-time immersion into the metal to be measured. At the same time, the thermoelectromotive force value of the sample sampled in the thermoelectromotive force measurement space and the solidification temperature of the sample sampled in the coagulation temperature measurement space are measured, and the carbon content determined by the coagulation temperature measurement method is used to determine the relevant carbon content. A method for measuring the amount of manganese in molten metal by calculating the effect of carbon number on the thermoelectromotive force value, taking this influence into account, and determining the manganese content using the thermoelectromotive force method. 2 At least two thermocouples each having a wire portion covered with heat-resistant insulating means and a hot junction exposed on the surface are placed in a space at a distance, one thermocouple hot junction is placed in the high temperature side space, and the other thermocouple is placed in the space on the high temperature side. The method for measuring the amount of manganese in molten metal according to claim 1, characterized in that the hot junction of the thermocouple is located in the low-temperature side space, and the hot junctions of both thermocouples are also used as electrodes for measuring thermoelectromotive force. .