JPH0746088B2 - Device for measuring silicon concentration in molten metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application]
This is a device for measuring the concentration of silicon (Si). [Prior Art] Regarding a measuring method and an apparatus for impurity elements in molten metal,
Applying the technology of oxygen concentration battery with solid electrolyte
JP-A-61-142455, JP-A-61-260155,
Opened in Japanese Unexamined Patent Publication No. 61-260156 and Japanese Unexamined Patent Publication No. 61-260157.
It is shown. This will be explained with reference to the drawings.
As shown in Fig. 3, a device for measuring the silicon concentration in molten iron M
In, the silicon sensor element 1 has oxygen ion conductivity.
Inside the tubular body formed by the solid electrolyte 2 having
A silicon oxide is provided on the outer surface of the cylindrical body while having the quasi-electrode 3.
Compound and / or silicon composite oxide deposited in spots
It also has a sub-electrode 4. The reference electrode 3 is a reference substance 5
It is embedded inside, and the reference substance 5 is a reference oxygen content.
It regulates the pressure and is used in conventional oxygen concentration batteries.
It is similar to what is described. The molten metal electrode 6 is
Separated from the recon sensor element 1
A potential difference measuring circuit is provided between the silicon sensor element 1 and
Form. Therefore, the molten metal electrode 6 and the reference electrode 3 have a potential
It is connected to the difference meter 7. In addition, 8 is a temperature measuring element. Therefore, according to this device, measurement in molten metal M should be performed.
The silicon activity is stable and constant on the surface of the sub-electrode 4.
It exists as a quasi-chemical equilibrium band. Therefore,
By measuring the potential difference appearing on the potentiometer 7,
It is possible to know the concentration of silicon in molten metal. [Problems to be Solved by the Invention] According to the above conventional measuring device, the silicon concentration in the molten metal is
It is excellent in that it can detect the
There is a problem that the output result is not accurate. In this regard, the present inventor has found that the silicon activity in the molten metal is
The amount varies greatly depending on the amount of carbon contained in the metal.
It was found that the amount of carbon was larger and smaller than the silicon concentration.
Found to be the cause of inaccurate detection of
It was. In addition, the above-mentioned measuring device is composed of molten iron / sub-electrode / solid electrolyte.
It uses the principle of measuring the oxygen partial pressure at the phase interface.
However, the present inventor used the measuring device to measure
Compared to the case of measuring silicon concentration, it looks like blast furnace hot metal gutter
For measuring the concentration of silicon in molten metal flowing in
In this case, the three-phase interface is renewed, resulting in an equilibrium state.
Is difficult to reach, the equilibrium arrival time becomes longer, and the detection results
It was discovered to be extremely unstable. Therefore, the present invention makes these detection results inaccurate.
There is a problem in removing the cause
The problem was solved by. [Means for Solving Problems] First, the measurement principle based on the above-described measurement device will be described.
In both cases, the amount of carbon in the molten metal affects the fluctuation of silicon activity.
Explain why. In the above measuring device, the silicon sensor element 1 is configured.
Solid electrolyte 2 is a zirconia solid electrolyte (oxygen concentration
And a sub-electrode 4 formed on the surface of the solid electrolyte 2
SiO₂Or SiO₂And SiO₂Complex oxides with other oxides,
For example ZrO₂＋ ZrSiO_FourIf the substance consists of
If the consensus element is immersed in molten iron, the sub-electrode / zirco
At the three-phase interface of near solid electrolyte / molten iron
A balanced state occurs. Si (in Fe) + O₂＋ ZrO₂= ZrSiO_Four (1) The equilibrium constant K1 (T) of (1) is as follows.Where aZrSiO_Four= 1, aZrO₂When = 1, the above K1 (T)
IsBecomes. Where K1 (T) is a function of temperature only, and thermodynamically
Since it is known, the oxygen partial pressure at the three-phase interface can be adjusted to the zirconia solid state.
If measured with an electrolyte, the amount of silicon (Si) in molten iron
The activity can be measured. By the way, the information necessary for controlling molten iron components is silicon (Si).
Not the activity, but the amount of silicon (Si) (% by weight)
Then, the silicon in the molten iron measured in this way
Convert (Si) activity into silicon (Si) content (wt%)
This explains the formula. Electromotive force of silicon sensor and silicon (Si) activity and temperature
The relation of is as follows.By transforming equation (4) and rearranging h (Si), the following equation is obtained.
It ’s on the street.However: h (Si); Henry standard activity K1 (T); Si (in Fe) + O₂＋ ZrO₂= ZrSiO_Four Equilibrium constant of equation (1) log K1 (T) = 41900 / T-10.99 Po₂(Ref); Reference substance (Mo-MoO₂) Equilibrium oxygen partial pressure Po₂(Ref) = exp (14.238-59049 / T) Pθ; electron conduction parameter log Pθ = 24.42-74370 / T T; absolute temperature F; Faraday constant 23052 (cal ・ V)^-1・ Mol^-1) R; Gas constant 1.98648 (cal ・ deg^-1・ Mol^-1) Henry's standard silicon activity h (Si) in molten iron is
It can be calculated from
[% Si] can be obtained. log h (Si) ＝ ▲ e^Si _Si▼ [% Si] ＋ ▲ e^C _Si▼ [% C] + log [Si] (6) However: ▲ e^Si _Si▼ = 0.109 ▲ e^C _Si▼ ＝ 0.198 Therefore, from the above measurement principle, the amount of silicon (Si) in molten iron
The concentration can be measured. By the way, when measuring the silicon concentration in molten iron,
As measured by the solid electrolyte silicon sensor,
Is the activity of silicon (Si) in molten iron, and this activity is
Greatly affects the fluctuation of the amount of carbon (C) contained in molten iron
I have a problem of receiving it. That is, the concentration of silicon (Si)
If the amount of carbon (C) changes,
Correspondingly, the silicon activity value also fluctuates, and the silicon sensor
Electric power (E.M.F.) also changes. The information necessary for controlling molten iron components is the activity of silicon (Si).
Not the amount of silicon (Si) (% by weight)
Silicon (Si) activity can be detected by consensus
Therefore, the activity is accurately converted to the amount of silicon (% by weight).
Information about the amount of carbon (C) is needed to convert
Becomes. Here, the amount of carbon (C) with respect to the electromotive force of the silicon sensor
Explain the effect of. The relationship between silicon activity, temperature, and electromotive force is shown in (1) above.
Is transformed, the electromotive force at carbon (C) fluctuation, that is, ΔC
If the change is ΔE, it is shown by the following equation. log h (Si) ＝ ▲ e^Si _Si▼ [% Si] ＋ ▲ e^C _Si▼ [% C] ＋ log
[% Si] log h ′ (Si) ＝ ▲ e^Si _Si▼ [% Si] ＋ ▲ e^C _Si▼ [% C
+ ΔC] + log [% Si] (9) (8) Formula- (7) Formula ΔE = ln {k1 (T) h '(Si)^-1/4+ Pθ^1/4} −ln {k1 (T) h (Si)^-1/4+ Pθ^1/4} (10) In equation (10), Pθ^1/4<< {K1 (T) h (Si)}
^-1/4And Eq. (10) should be simplified as
Can be done.In formula (11), F = 23052 (cal ・ V^-1・ Mol^-1) R = 1.98648 (cal ・ deg^-1・ Mol^-1) ▲ e^C _SiSubstituting ▼ = 0.198, the effect of the amount of carbon (C) on the cell electromotive force
Can be expressed as ΔE (mV) = 9.824 x 10^-3× T (K) × ΔC (%) (12) When measuring silicon in molten iron using a known sensor
The amount of carbon (C) in molten iron is saturated or supersaturated.
Therefore, since it does not affect the electromotive force theoretically,
According to the experiments conducted by the invention, the actual operating conditions are
The amount of carbon (C) in molten iron varies considerably,
About 1% of the change was recognized in the
It has been found that the change in sensor electromotive force reaches approximately 17 mV.
It was. Therefore, in the conventional silicon sensor,
I must accept the measurement error in the range of change.
There is a problem. Therefore, the present inventor accurately grasps the amount of silicon in molten iron.
In order to achieve
Carbon fluctuations do not influence the calculation of the quantity.
We focused on the fact that certain conditions are necessary for measurement. by the way,
Various studies have been conducted on the saturated solubility of carbon.
However, the saturated solubility of carbon is generally calculated by
Is expressed. % C = 1.52 + 2.39 × 10^-3Xt (° C) According to this, if the molten iron temperature is low, the carbon saturation solubility is low.
On the contrary, the higher the molten iron temperature, the higher the carbon saturation solubility.
Become. Therefore, the above-mentioned fluctuation of carbon content in the molten iron is due to the molten iron temperature.
It is due to the change of. Therefore, the inventor
The carbon in the molten iron is always kept saturated regardless of the change in
Knowing that you can solve the above problems by holding
It was. Therefore, according to the present invention, the molten metal near the silicon sensor element is
By adopting a method of actively supplying carbon to iron
Therefore, it is important to keep the carbon content saturated during the measurement period.
It is a feature. In addition, to measure the silicon concentration using a known sensor
When molten iron is flowing like blast furnace hot metal gutter,
As in the past, a bare sensor element is directly immersed in molten iron.
Then, the above-mentioned three-phase interface of molten iron / sub-electrode / solid electrolyte is
Since it is updated, the three-phase interface is unlikely to reach an equilibrium state,
It is said that the equilibrium time becomes longer and the instructions become unstable.
There is a problem. Thus, the inventor has found that molten iron near the silicon sensor element
Isolate from the influence of molten iron flow so that it does not flow during the measurement period
Have found that is advantageous. Moreover, like this
Prevent molten iron near the silicon sensor element from flowing
As a result, the carbon saturation state by the above-mentioned carbon supply means
Is easy to maintain. Therefore, the present invention is
Retains molten iron that has penetrated around the recon sensor element
It is characterized by forming a chamber. Therefore, the present invention is configured as a means of the above characteristics.
Is based on an example of a solid electrolyte having oxygen ion conductivity.
It has an electrode and a silicon acid on the other side of the solid electrolyte.
With a sub-electrode made of oxide and / or silicon composite oxide
And the silicon sensor element
Molten gold forming a potential difference measuring circuit between the sensor and the sensor element
With a metal pole: at least the silicon
Forming and retaining a molten metal retention chamber around the sensor element
A partition having an opening for allowing molten metal to enter the chamber;
Means for supplying carbon into the molten metal retention chamber
There is a point. [Examples] Examples of the present invention will be described in detail below with reference to the drawings. (First Embodiment) In the first embodiment shown in FIGS. 1 and 2, silicon is used.
The concentration measuring device includes a silicon sensor element 1 and a molten iron electrode.
(Molten metal electrode) 6 and temperature measuring element 8 are assembled together
It is included. The silicon sensor element 1 is based on Fig. 21.
The same as the above-mentioned conventionally known ones, the oxygen ion
Cylindrical cylinder with a bottom formed of a solid electrolyte 2 having conductivity
Has a reference electrode (not shown) inside the
Silicon oxide on the outer surface in spots or any other form
It has an attached sub-electrode 4. The solid electrolyte 2 is
In addition to the cylindrical shape as shown, it can be molded into various shapes
In short, a reference electrode is provided on one side of the solid electrolyte 2.
In addition, the sub-electrode 4 is provided on the other side, and molten iron (hot metal, molten steel
Other molten metal), the molten iron between the molten iron electrode 6 and
Any device that forms a potential difference measurement circuit via the above may be used. Well
Moreover, the sub-electrode 4 is directly deposited on the surface of the solid electrolyte 2.
In addition, it is supported by the solid electrolyte 2 with a minute gap.
May be The silicon sensor element 1, molten iron electrode 6, temperature measuring element 8 are preferably
To be specific, each base end should be the tip of the head 9 made of ceramic or the like.
Retained buried in refractory cement 10 filled in the opening
The The head 9 has a resistance to the outer surface as shown by the chain line in FIG.
It is inserted into a holder 11 consisting of a paper tube covered with a fire
Configure the probe with. In Fig. 2, 12 is
Reference electrode lead wire of silicon sensor element, 13 is molten iron electrode lead
The lead wire, 14 is the temperature measuring element lead wire,
Although it is inserted in the base end part of 9,
Connector on the holder 11 side through the connector.
It is desirable to be connected to the lead wire. Use
Sometimes, the lead wire 12 of the silicon sensor element 1 and the molten iron electrode 6
The lead wire 13 of is similar to the conventional sensor shown in FIG.
It is connected to a potentiometer. Thus, in this first embodiment, the silicon sensor element is
1, molten iron electrode 6, temperature measuring element 8 are placed on the cap-shaped partition 15
It is surrounded, and the base end of the partition 15 is attached to the head 9.
It is fixed. The partition body 15 has molten iron penetrated inside.
To do this, open the opening 16a at the tip and the opening 16b at the peripheral wall.
The molten gold surrounded by the partition 15
It forms a metal retention chamber 17. This partition 15 is
It does not break when immersed, and the amount of silicon in molten iron
While measuring (usually about 30 to 120 seconds)
It retains its shape without disappearing due to loss, etc.
If so, the material does not matter. However, it disappears after the measurement is completed.
I don't mind. Further, in the molten metal retention chamber 17, charcoal is
Means for supplying the element are provided. This carbon supply means
In the molten metal retention chamber 17, which will be described later in a preferred embodiment,
Positively saturates the carbon in the molten iron accumulated in the
For example, the material of the cap-shaped partition body 15 is
As such, it shall leach carbon by the heat of molten iron.
This can be done by and. (Example of Partition) In the above-described example, the silicon partition is formed by the cap-shaped partition 15.
Sensor element 1, molten iron electrode 6, temperature measuring element 8
In addition to the above, the embodiment shown in FIGS.
It is possible to adopt. In the embodiment shown in FIG. 3, the head 9 has a silicon sensor.
The element 1 and the temperature measuring element 8 are provided.
No separate molten iron electrode 6 is provided. Cap
The peg-shaped partition 15 includes the silicon sensor element 1 and the temperature measuring element 8.
It is fixed to the head 9 while being surrounded, and the openings 16a and 16b are opened.
However, the point that the molten metal retention chamber 17 is formed inside is that
But the partition 15 itself is made of a conductive material.
Has been made. Therefore, in this case, the partition 15 is the molten iron electrode 6
It also has the function of and is connected to the lead wire 13.
At this time, carbon graphite was used as the conductive material forming the partition 15.
If a fight is used, the partition body 15 will have the above-mentioned carbon supplier.
It will also function as a step, and the structure will be simple.
If the partition 15 is formed in a cap shape,
Due to the cooling effect of the partition body 15, it flows into the molten metal retention chamber 17
It is considered that there is a temperature difference between the molten iron and the external molten iron.
However, the temperature measuring element 8 is arranged in the retention chamber 17 as in this embodiment.
If it is installed, the molten iron temperature in the retention chamber 17 can be measured.
It is advantageous. In the embodiment shown in FIG. 4, the head 9 has a silicon sensor element.
1 and the molten iron electrode 6 are provided and have openings 16a, 16b
The cap-shaped partition 15 forming the molten metal retention chamber 17 is
A head 9 surrounding the silicon sensor element 1 and the molten iron electrode 6.
It is fixed to. The temperature measuring element 8 is the conventional one shown in FIG.
As in the example, it may be used separately from the measuring device of the present invention.
However, as shown by the chain line in Fig. 4, outside the cap-shaped partition 15.
It may be attached to the head 9 in advance. In the embodiment of FIG. 5, the silicon sensor element 1 is attached to the head 9.
Only, with openings 16a and 16b, and molten metal retention inside
The silicon partition is formed by the cap-shaped partition 15 that forms the chamber 17.
The sensor element 1 is surrounded. The cap-shaped partition 15 is
As in the embodiment shown in FIG.
Function as molten iron pole 6 by connecting to the lead wire 13
It has both. Also in this embodiment, the temperature measuring element 8 is
Although it can be used separately from the measuring device of the present invention,
It may be attached to the head 9 outside the partition 15 as shown by the line.
Yes. In the embodiment shown in FIG. 6, the head 9 has a silicon sensor element.
1 and the molten iron electrode 6 are provided and have openings 16a, 16b
By the cap-shaped partition 15 that forms the molten metal retention chamber 17 in
It surrounds only the silicon sensor element 1. Obey
The molten iron electrode 6 is outside the partition 15. The temperature measuring element 8
Although it may be used separately from the measuring device of the present invention, the partition 15
It may be attached to the head 9 outside the. Thus, the silicon concentration measuring device of the present invention is
Which requires only the sensor element 1 and the molten iron electrode 6.
Therefore, the temperature measuring element 8 is not always essential. Also,
The molten iron electrode 6 does not need to exist independently, and
It is free to construct the molten iron electrode by the cut body 15. Change
In addition, the molten metal retention chamber 17 formed by the partition body 15 is
It is necessary to form it around the recon sensor element 1.
However, in addition to that, it is essential to form around the molten iron electrode 6 etc.
Not. By the way, in the embodiment shown in FIG. 2 and FIG.
The outer diameter of the partition body 15 increases, and it receives resistance from the molten iron flow.
Therefore, it is suitable for measurement when molten iron is at rest or close to rest.
Are suitable. On the other hand, in the embodiment of FIGS. 4 to 6,
Because the outer diameter of the cap-shaped partition 15 is reduced, molten iron
The resistance due to the flow can be reduced, and the flow of the molten iron flow is fast.
It is advantageous when In addition, the cap-shaped partition 15 is small
If it is made smaller, the volume of the molten metal body flow chamber 17 will be correspondingly smaller.
Therefore, the molten iron in the retention chamber 17 is supplied by the carbon supply means.
It has the advantage that it is easy to maintain the carbon content of the saturated state. Change
In addition, if the molten iron flow velocity to be measured is high or the molten iron temperature is high.
If the cap-shaped partition 15 is small, the molten iron
The heat exchange due to
The temperature and the temperature can be made equal in a short time, and the response time
This is advantageous in that it enables short measurements. (Example of Partition Opening) Each cap-shaped partition as shown in FIG. 3 to FIG.
In the body 15, the molten metal is allowed to enter the molten metal retention chamber 17
In addition to the above, the structure of the opening for closing is shown in FIG.
It is possible to adopt the embodiment shown in FIG. In the embodiment shown in FIG. 7, the cap-shaped partition 15 has a tip.
While the opening 16a is provided on the peripheral part, the opening 16b and the air are provided on the peripheral wall.
The punched hole 16c is opened. The air vent hole 16c is the opening 16
It is preferable that it is located higher than b. Therefore, open
Molten metal penetrates into the molten gold residence chamber 17 through the mouths 16a and 16b.
When doing so, the air in the chamber is appropriately exhausted from the hole 16c.
It is possible to fill the room with molten metal. In the embodiment shown in FIG. 8, the cap-shaped partition body 15 has
Although it has the opening 16a, only the air vent hole 16c is provided in the peripheral wall.
Has been established. In the embodiment of FIG. 9, the cap-shaped partition body 15 is
The openings 16a are circumferentially spaced at the slightly retracted positions.
Open a plurality of holes and open only the air vent hole 16c on the peripheral wall.
There is. In the embodiment shown in FIG. 10, the cap-shaped partition body 15 is provided at the tip.
There are no openings, and multiple openings 16b are opened in the peripheral wall.
ing. The opening 16b has a relatively large diameter and a plurality of openings.
Therefore, it can also serve as the air bleeder. In the embodiment shown in FIG. 11, in the same manner as in FIG.
Place several openings 16b with the phases vertically shifted.
There is. Therefore, the opening 16b located above does not remove air.
Also serve. In the embodiment shown in FIG. 12, the cap-shaped partition body 15 is provided at the tip.
There is no opening, and the opening 16b is opened in the peripheral wall,
An air vent hole 16c is provided above the portion 16b.
The (Example of Carbon Supply Means) The carbon supply means of the present invention retains in the molten metal retention chamber 17
It positively saturates the carbon in the molten iron.
As described above with reference to FIGS. 3 and 5,
The material of the partition 15 itself elutes carbon by the heat of molten iron
Molding with carbon graphite to
In this case, the partition 15 itself is made of carbon material.
Partition body made of any material other than molding
A carbon material is attached to the surface of 15 or the partition 15 is formed.
Implemented by impregnating the shape material with a carbon material
You can also In addition, as shown in Figs.
It is also possible to adopt an example. That is, in the embodiment of FIG. 13, the silicon sensor element 1,
Refractory cement for head 9 supporting molten iron electrode 6 and temperature measuring element 8
The upper part of 10 is made of carbon material facing the molten metal retention chamber 17.
The shaped plate 18 is polymerized and fixed. The silicon cell
The sensor element 1, the molten iron electrode 6, and the temperature measuring element 8 extend through the plate-shaped body 18.
However, an insulating bush is interposed in the insertion hole of the plate-shaped body 18.
ing. In the embodiment of FIG. 14, from the head 9 to the molten metal retention chamber 17
A rod-shaped body 19 formed of a carbon material extends on the. In this way, in the molten metal retention chamber 17, cylindrical, plate-shaped or other
Inserting a separate carbon material shaped into any shape
So that carbon is eluted in the molten iron in the retention chamber 17
However, this can constitute a carbon supply means. Furthermore, although not shown, granular or powdery carbon materials
A shell that can be broken or carbon permeable in the enclosed molten iron
By charging the molten metal retention chamber 17 into the retention chamber 17
It is configured so that carbon gradually exudes into the molten iron inside the
Can also be used as a carbon supply means. In this case,
To prevent the sensor from being affected by the reaction with iron, carbon
Place the material so that it does not come into direct contact with the sensor element.
Good. (Second Embodiment) The present invention positively carbonizes molten iron in the vicinity of a silicon sensor element.
Element is supplied, and the amount of carbon in the measured molten iron is saturated.
Normalization, and the change width of the electromotive force of the sensor is made as small as possible.
The goal is to
The cap-shaped partition 15 shown in the first embodiment is not always necessary.
It doesn't matter. That is, as described in claim 1 of the present patent claim
The embodiment of the invention is, for example, as shown in FIG.
A carbon supply means such as a carbon rod 20 is arranged around the sensor element 1.
It can be placed. In this case,
On the outer periphery of the sensor element 1, the caps as in each of the above embodiments are provided.
No molten metal retention chamber is formed by the cup-shaped partition
However, when measuring molten iron when it is at rest or close to rest,
Then, there is a sufficient effect to achieve the above purpose.
Although not shown, in FIG.
If necessary, the molten iron electrode and temperature measuring element are supported. (Third Embodiment) In the third embodiment shown in FIG. 16, the head 9 is made of silicon.
Supports sensor element 1, and if necessary, molten iron electrode and temperature measuring element
The fact that the child (the chair in the drawing) is supported is the same as in the first embodiment.
Similarly, the partition body 15 has its base end supported by the head 9.
A plurality of claws extending in the direction of the tip of the silicon sensor element 1.
It consists of pieces 15a and 15a. The nail pieces are spaced from each other
And has an opening 16 formed between them. Therefore, this third
Even in the embodiment, the silicon sensor element is
A molten metal retention chamber 17 is formed around the child 1 and has an opening 16
The molten metal that has entered from the inside is retained in the retention chamber 17.
Can be done. The carbon supply means is the same as in the above-mentioned embodiment.
The partition 15 itself may be made of a carbon material, or separately.
A carbon material may be charged in the retention chamber 17. As described above, in the present invention, the partition body 15 is made of silicon.
Forming the molten gold storage chamber 17 around the entire circumference of the sensor element 1
It is not necessary to be
Anything can be done. In addition, the molten metal by the partition 15
The present invention is used for the partition between the residence chamber 17 and the molten metal outside.
Depending on the flow state of molten iron for which the silicon concentration should be measured
You can freely change the design appropriately.
When it is relatively close to the stationary state, the partition body 15 is formed in a net shape.
You can also (Test Example 1) The conventionally known measuring device shown in FIG. 21 and the one shown in FIG.
Molten iron under the same conditions with the measuring device according to the embodiment of the present invention
The silicon concentration inside was measured. The present invention shown in FIG.
The product is a silicon sensor element 1 supported by the head 9 and melted.
The iron electrode 6 and the temperature measuring element 8 are enclosed by a cap-shaped partition 15.
The cap-shaped partition 15 is made of a car.
Bon graphite. The cap-shaped partition 15 is at the tip
It has an opening 16a that is a circular hole, and extends vertically at one location on the peripheral wall.
It has a slit-shaped opening 16b. The test results appearing on the potentiometer are as shown in Figure 18.
The solid line is the conventional example, and the broken line is the output waveform of the product of the present invention.
The The test measurement is for the gun in the gun pot, and the gun temperature is
1358 ~ 1413 ℃, melting gun composition, carbon (C) is 3.99 ~ 4.89
%, Silicon (Si) is 0.08 to 0.38%.
Power indication equilibrium arrival time (Ta; Conventional example, Tb; Implementation of the present invention
Product), ΔE is the fluctuation range of the electromotive force indicating balance part (ΔEa; conventional example,
ΔEb; product of the present invention). According to this, compared to the conventional example, the product of the present invention is
The electromotive force indicating equilibrium arrival time (Tb) is short, so the response time is
Is short, the fluctuation range (ΔEb) of the electromotive force indicating balance part is small,
It was confirmed that the difference between the upper and lower limits was small. The test was conducted 20 times, and the results are shown in Table 1 below.
It was on the street.(Test Example 2) The conventionally known measuring device shown in FIG. 21 and the one shown in FIG.
With the measuring device according to the embodiment of the present invention, a melting gun under the same conditions
The silicon concentration inside was measured. The present invention shown in FIG.
The product is a head 9, a silicon sensor element 1 and a temperature measuring element 8.
The silicon sensor element that supports the
It surrounds only child 1. 15 cap-shaped partitions
The material is carbon graphite, and the partition 15 itself
Also serves as the molten iron pole 6. The cap-shaped partition 15 is circular at the tip
It has an opening 16a in the shape of a hole, and is longitudinally located at one location on the peripheral wall.
It has a slit-shaped opening 16b. The test results appearing on the potentiometer are as shown in Figure 20.
The solid line is the conventional example, and the broken line is the output waveform of the product of the present invention.
The The test measurement is for the gun in the blast furnace gutter, and the gun temperature is
1400 to 1522 ℃, melting gun composition is carbon (C) 4.2 to 4.88
%, Silicon (Si) is 0.15 to 0.50%.
Power indication equilibrium arrival time (Ta; conventional example, Tc; implementation of the present invention
Product), ΔE is the fluctuation range of the electromotive force indicating balance part (ΔEa; conventional example,
ΔEc; product of the present invention). According to this, compared to the conventional example, the product of the present invention is
The electromotive force indicating equilibrium arrival time (Tc) is short, so the response time is
Is short, and the fluctuation range (ΔEc) of the electromotive force indicating balance part is small.
It was confirmed that the difference between the upper and lower limits was small. The test was performed 19 times, and the results are shown in Table 2 below.
It was on the street.[Effect of the invention] According to the present invention described in claim 1, carbon supply
Carbon of molten metal near the silicon sensor element by the feeding means
The amount can be kept saturated during the measurement period.
Therefore, fluctuations in silicon activity due to fluctuations in carbon content in molten metal
The sensor output is stable and accurate measurement is possible.
Becomes. Further, according to the present invention described in claim 2,
Molten metal stays around the silicon sensor element by the partition
A means for forming a chamber and supplying carbon into the retention chamber was provided.
Therefore, the molten metal flows violently in the retention chamber during the measurement period.
Therefore, the amount of carbon in the metal must be kept saturated.
It is easy to perform and when measuring in a place with flow
However, the three-phase interface of molten metal / sub-electrode / solid electrolyte is updated
Is less likely to occur and the equilibrium arrival time is shortened.
In addition, stable instructions can be obtained, which is fast and stable.
This has the effect of enabling measurement.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention partially broken away, and FIG. 2 is a side view showing a partial cross section of the same embodiment, and FIG.
FIGS. 6 to 6 are side views showing partially different sectional embodiments of the partition body, and FIGS. 7 to 12 are sectional views showing different embodiments of the opening of the partition body, FIG. 13 and FIG. 14th
FIG. 15 is a sectional view showing a different embodiment of carbon supplying means, FIG. 15 is a perspective view showing a second embodiment of the present invention, and FIG. 16 is a perspective view showing a partially broken third embodiment of the present invention. Figure, No. 17
FIG. 18 is a sectional view showing a product of the present invention used in Test Example 1, No. 18
Fig. 19 is a waveform diagram showing the test results of the same test example and the conventional example.
FIG. 1 is a sectional view showing a product of the present invention used in Test Example 2,
Figure 20 is a waveform diagram showing the test results of the same test example and the conventional example.
Fig. 21 is a cross-sectional view showing the usage state of a conventionally known example. 1 ... Silicon sensor element, 2 ... Solid electrolyte, 3 ... Reference electrode, 4 ... Sub electrode, 6 ... Molten metal electrode, 7 ... Potentiometer, 8 ...
… Temperature measuring element, 15 …… Partitioner, 16 (16a, 16b) …… Opening, 17
…… Molten metal retention chamber, 18, 19, 20 …… Carbon supply means (plate, rod, carbon rod).

Claims (2)

[Claims] 1. A silicon sensor element having a reference electrode on one side of a solid electrolyte having oxygen ion conductivity and a sub-electrode made of silicon oxide and / or silicon composite oxide on the other side of the solid electrolyte. A molten metal electrode forming a potential difference measurement circuit between the silicon sensor element and the silicon sensor element in a molten metal: comprising means for supplying carbon to the periphery of the silicon sensor element Measuring device for silicon concentration in molten metal. 2. A silicon sensor element having a reference electrode on one side of a solid electrolyte having oxygen ion conductivity and a sub-electrode made of silicon oxide and / or silicon composite oxide on the other side of the solid electrolyte. In a molten metal having a molten metal electrode forming a potential difference measuring circuit between the silicon sensor element and the silicon sensor element: a molten metal retention chamber is formed at least around the silicon sensor element, and An apparatus for measuring silicon concentration in molten metal, comprising: a partition body having an opening for allowing molten metal to enter; and means for supplying carbon into the molten metal retention chamber.