WO2017096711A1 - Reference electrode for oxygen sensor and preparation method therefor, and oxygen sensor - Google Patents

Abstract

A reference electrode for an oxygen sensor, prepared from the following raw materials in percentages by weight: 40-99.96 wt% of Cr; 0.01-30 wt% of Cr2O3; 0.01-10 wt% of MnO; 0.01-10 wt% of CoO; and 0.01-10 wt% of NiO. For the reference electrode, MnO, CoO, and NiO are added to a Cr+Cr2O3 system, such that electrode powder has high reactivity and a large effective surface area. An oxygen sensor prepared using the reference electrode is quick in response, has a low temperature measurement deviation, and is applicable in both high-oxygen and low-oxygen environments. Results show that the provided oxygen sensor is able to respond within 4s, has a temperature measurement deviation less than 2°C, and is applicable to both high-oxygen and low-oxygen environments.

Description

Reference electrode for oxygen battery sensor, preparation method thereof and oxygen battery sensor

This application claims priority on Chinese patent application filed on December 10, 2015, Chinese Patent Office, application number 201510920382.4, titled "a reference electrode for oxygen battery sensor and its preparation method, and an oxygen battery sensor" The entire contents are hereby incorporated by reference.

Technical field

The invention belongs to the technical field of oxygen battery sensors, and particularly relates to a reference electrode for an oxygen battery sensor, a preparation method thereof and an oxygen battery sensor.

Background technique

The zirconia solid electrolyte oxygen sensor (oxygen battery sensor) direct oxygenation technology is listed as one of the three major scientific research achievements in the world of iron and steel metallurgy in the 1970s.

At present, the commonly used oxygen battery sensor is a tubular sensor. The specific structure is shown in Fig. 16. Fig. 16 is a schematic structural view of the tubular oxygen battery sensor. The core technology of the oxygen battery sensor lies in the oxygen battery. The working principle of the oxygen battery is as follows: the oxygen content in the molten steel is measured by the zirconia solid electrolyte. When the probe is inserted into the molten steel, the electrode reaction will occur at the electrode interface of the electrolyte, and respectively established. Different balanced electrode potentials, the oxygen measurement technology of the solid electrolyte concentration battery in the probe is composed of a half-cell and a thermocouple, which can simultaneously measure the temperature and oxygen content of the molten steel. The main test principle is the reference of a known oxygen partial pressure. The specific electrode and the other molten steel having the oxygen content to be measured are connected by the conductive property of the oxygen ion solid electrolyte to constitute an oxygen concentration battery. By measuring the temperature of the molten steel and the oxygen potential, the Nernst equation can be used to calculate the oxygen content in the molten steel.

The core technology of the oxygen battery is the preparation of the zirconia zirconium tube and the reference electrode, wherein the reference electrode has a greater influence on the performance of the oxygen battery.

At present, the reference electrode system commonly used in the market is basically a metal + metal oxide system, such as Cr+Cr ₂ O ₃ or Mo+MoO _{2 ,} etc., such a system can constitute a reference electrode having a certain oxygen partial pressure, and constitutes a fixed electrode. Half cell of the oxygen sensor. However, the oxygen battery sensor prepared by the reference electrode of the above system has a slow response speed, a large measurement temperature deviation, and can not be applied to both high and low oxygen environments.

Summary of the invention

In view of this, the technical problem to be solved by the present invention is to provide a reference electrode for an oxygen battery sensor, a preparation method thereof, and an oxygen battery sensor, and the response speed of the oxygen battery sensor provided by the present invention is provided. Fast, small measurement temperature deviation, and high and low oxygen environment can be applied.

The invention provides a reference electrode for an oxygen battery sensor, which is prepared from the following mass percentage components:

40 wt% to 99.96 wt% of Cr;

0.01 wt% to 30 wt% of Cr ₂ O ₃ ;

0.01 wt% to 10 wt% of MnO;

0.01% to 10% by weight of CoO;

0.01% by weight to 10% by weight of NiO.

Preferably, it is prepared from the following mass percentage components:

50% by weight to 80% by weight of Cr;

10 wt% to 25 wt% of Cr ₂ O ₃ ;

1 wt% to 8 wt% of MnO;

1wt% to 8wt% CoO;

1 wt% to 8 wt% of NiO.

The invention also provides a preparation method of a reference electrode for an oxygen battery sensor, comprising the following steps:

Ball milling of 40 wt% to 99.96% by weight of Cr, 0.01 wt% to 30 wt% of Cr ₂ O ₃ , 0.01 wt% to 10 wt% of MnO, 0.01 wt% to 10 wt% of CoO, and 0.01 wt% to 10 wt% of NiO Mixing to obtain a mixed slurry;

The mixed slurry is sequentially dried, ground, sintered, and pulverized to obtain a reference electrode for an oxygen battery sensor.

Preferably, the ball milling speed is 100-300 r/min, and the ball milling time is 5-10 h.

Preferably, the specific method of sintering is:

It is heated to 1100-1400 ° C at a heating rate of 1 to 6 ° C / min, and kept for 3 to 6 hours.

The present invention also provides an oxygen battery sensor comprising an oxygen battery, a thermocouple, a mud head and a protective paper tube, wherein the oxygen battery comprises:

Zirconium tube

a reference electrode disposed at an inner bottom end of the zirconium tube;

An alumina powder layer disposed inside the zirconium tube and above the reference electrode;

a metal wire penetrating through the reference electrode and the alumina powder layer, the metal wire is in contact with a bottom end of the inside of the zirconium tube, and the other end extends to the outside of the zirconium tube;

The reference electrode is selected from the reference electrode for an oxygen battery sensor according to claim 1 or 2.

Preferably, the zirconium tube is prepared from a powder and a binder, and the powder comprises the following components:

72wt% to 95wt% ZrO ₂ ;

4wt% to 15wt% HfO ₂ ;

A mixed powder of 0.5 wt% to 15 wt% of a metal oxide including one or more of CaO, MgO, Y ₂ O ₃ and CeO ₂ .

Preferably, the volume ratio of the powder to the binder is (35-60): (40-65).

Preferably, the binder is selected from one or more of the group consisting of ethylene and vinyl acetate copolymers, high density polyethylene, stearic acid and paraffin wax.

Preferably, the binder is selected from the group consisting of ethylene (9 to 20): (7 to 10): (8 to 15): (55 to 76) ethylene and vinyl acetate copolymer, high density polyethylene, and hard. a mixture of fatty acids and paraffin.

Compared with the prior art, the present invention provides a reference electrode for an oxygen battery sensor, which is prepared from the following mass percentages of raw materials: 40 wt% to 99.96% by weight of Cr; 0.01 wt% to 30 wt% of Cr ₂ O ₃ ; 0.01 wt% to 10 wt% of MnO; 0.01 wt% to 10 wt% of CoO; 0.01 wt% to 10 wt% of NiO. The reference electrode provided by the present invention adds MnO, CoO and NiO to the Cr+Cr ₂ O ₃ system to make the electrode powder highly reactive and has a large effective surface area. The oxygen battery sensor prepared by using the reference electrode has a fast response speed, a small measurement temperature deviation, and is applicable to both high and low oxygen environments.

The results show that the oxygen battery sensor provided by the invention has a response speed of <4 s, a measurement temperature deviation of less than 2 ° C, and can be applied in both high oxygen and low oxygen environments.

DRAWINGS

1 is an electron micrograph of a reference electrode powder prepared in Example 1;

2 is a graph showing performance test results of an oxygen battery sensor under high oxygen concentration conditions prepared in Example 1;

3 is a graph showing performance test results of an oxygen battery sensor under high oxygen concentration conditions prepared in Example 1;

4 is a graph showing performance test results of an oxygen battery sensor under low oxygen concentration conditions prepared in Example 1;

5 is a graph showing performance test results of an oxygen battery sensor under the condition of low oxygen concentration prepared in Example 1;

6 is an electron micrograph of a reference electrode powder prepared in Example 2;

7 is a graph showing performance test results of an oxygen battery sensor under high oxygen concentration conditions prepared in Example 2;

8 is a graph showing performance test results of an oxygen battery sensor under high oxygen concentration conditions prepared in Example 2;

9 is a graph showing performance test results of an oxygen battery sensor under low oxygen concentration conditions prepared in Example 2;

10 is a graph showing performance test results of an oxygen battery sensor under low oxygen concentration conditions prepared in Example 2;

11 is an electron micrograph of a reference electrode powder prepared in Example 3;

12 is a graph showing performance test results of an oxygen battery sensor under high oxygen concentration conditions prepared in Example 3;

13 is a graph showing performance test results of an oxygen battery sensor under high oxygen concentration conditions prepared in Example 3;

14 is a graph showing performance test results of an oxygen battery sensor under low oxygen concentration conditions prepared in Example 3;

15 is a graph showing performance test results of an oxygen battery sensor under low oxygen concentration conditions prepared in Example 3;

Figure 16 is a schematic view showing the structure of a tubular oxygen battery sensor.

detailed description

The invention provides a reference electrode for an oxygen battery sensor, which is prepared from the following mass percentages of raw materials:

40 wt% to 99.96 wt% of Cr;

0.01 wt% to 30 wt% of Cr ₂ O ₃ ;

0.01 wt% to 10 wt% of MnO;

0.01% to 10% by weight of CoO;

0.01% by weight to 10% by weight of NiO.

The reference electrode for an oxygen battery sensor provided by the present invention comprises Cr, and the Cr is added in an amount of 40% by weight to 99.96% by weight, preferably 50% by weight to 90% by weight, more preferably 60% by weight to 80% by weight.

The reference electrode for an oxygen battery sensor provided by the present invention further comprises Cr ₂ O ₃ ; the Cr ₂ O ₃ is added in an amount of 0.01 wt% to 30 wt%, preferably 1 wt% to 25 wt%, more preferably 5 wt% to 20 wt%. %.

The reference electrode for an oxygen battery sensor according to the present invention further includes MnO, and the MnO is added in an amount of 0.01% by weight to 10% by weight, preferably 0.5% by weight to 9% by weight, more preferably 1% by weight to 8% by weight.

The reference electrode for an oxygen battery sensor provided by the present invention further comprises CoO, and the CoO is added in an amount of 0.01% by weight to 10% by weight, preferably 0.5% by weight to 9% by weight, more preferably 1% by weight to 8% by weight.

The reference electrode for an oxygen battery sensor provided by the present invention further comprises NiO, and the NiO is added in an amount of 0.01% by weight to 10% by weight, preferably 0.5% by weight to 9% by weight, more preferably 1% by weight to 8% by weight.

Preferably, the reference electrode is prepared from the following mass percentage components: 50 wt% to 80 wt% Cr; 10 wt% to 25 wt% Cr ₂ O ₃ ; 1 wt% to 8 wt% MnO; 1 wt% to 8 wt. % CoO; 1 wt% to 8 wt% NiO.

The invention also provides a preparation method of a reference electrode for an oxygen battery sensor, which comprises the following steps:

Ball milling of 40 wt% to 99.96% by weight of Cr, 0.01 wt% to 30 wt% of Cr ₂ O ₃ , 0.01 wt% to 10 wt% of MnO, 0.01 wt% to 10 wt% of CoO, and 0.01 wt% to 10 wt% of NiO Mixing to obtain a mixed slurry;

The mixed slurry is sequentially dried, ground, sintered, and pulverized to obtain a reference electrode for an oxygen battery sensor.

In the present invention, Cr, Cr ₂ O ₃ , MnO, CoO and NiO are first ball-milled to obtain a mixed slurry.

Among them, the Cr, Cr ₂ O ₃ , MnO, CoO, and NiO are all in a powder form. The manner in which the ball milling is mixed in the present invention is not particularly limited, and a ball milling mixing method known to those skilled in the art may be used. In the present invention, ball milling mixing is preferably carried out as follows:

Cr powder, Cr ₂ O ₃ powder, MnO powder, CoO powder, and NiO powder were mixed with an ethanol solution, placed in a ball mill jar, and ball-milled at a rate of 100 to 300 r/min for 5 to 10 hours.

After the mixed slurry is obtained, the mixed slurry is dried and ground to obtain a mixed powder.

The specific method for drying and grinding the mixed slurry of the present invention is not particularly limited, and a drying and grinding method known to those skilled in the art may be used. In the present invention, the drying is preferably vacuum drying.

In the present invention, it is preferred to subject the ground mixed powder to sieving and classifying. Preferably, a mixed powder of 0.25 μm to 1 μm is used for the preparation of the reference electrode.

The obtained mixed powder was sintered and pulverized to obtain a reference electrode powder.

Specifically, the mixed powder is placed in a tube furnace and vacuum sealed. It is placed in a high-temperature heat treatment furnace, heated at a heating rate of 1 to 6 ° C / min to 1100 to 1400 ° C, and kept for 3 to 6 hours to obtain a reference electrode powder.

The reference electrode powder was placed in a zirconium tube to obtain a reference electrode for an oxygen battery sensor.

Preferably, the amount of the reference electrode powder added to the oxygen battery sensor is preferably from 30 to 150 mg.

The present invention also provides an oxygen battery sensor comprising an oxygen battery, a thermocouple, a mud head and a protective paper tube, wherein the oxygen battery comprises:

Zirconium tube

a reference electrode disposed at an inner bottom end of the zirconium tube;

An alumina powder layer disposed inside the zirconium tube and above the reference electrode;

A metal wire penetrating through the reference electrode and the aluminum powder, one end of the metal wire is in contact with the bottom end of the inside of the zirconium tube, and the other end extends to the outside of the zirconium tube.

The oxygen battery of the oxygen battery sensor provided by the present invention comprises a zirconium tube.

In the present invention, the zirconium tube is preferably prepared from a powder and a binder, and the powder includes the following components:

70 wt% to 95 wt% of ZrO ₂ ;

4wt% to 15wt% HfO ₂ ;

A mixed powder of 0.5 wt% to 15 wt% of a metal oxide including one or more of CaO, MgO, Y ₂ O ₃ and CeO ₂ .

In the present invention, the raw material for preparing the zirconium tube includes ZrO ₂ powder, and the ZrO ₂ powder is added in an amount of 70% by weight to 95% by weight, preferably 71% by weight to 80% by weight, more preferably 72% by weight to 85% by weight. %.

The raw material for preparing the zirconium tube further includes HfO ₂ powder, and the HfO ₂ powder is added in an amount of 4 wt% to 15 wt%, preferably 5 wt% to 12 wt%, more preferably 8 wt% to 10 wt%.

The raw material for preparing the zirconium tube further includes a mixed powder of a metal oxide, and the mixed powder of the metal oxide is added in an amount of 0.5% by weight to 20% by weight, preferably 5% by weight to 19% by weight. In the present invention, the mixed powder of the metal oxide includes one or more of CaO, MgO, Y ₂ O ₃ and CeO ₂ .

In the present invention, the raw material for preparing the zirconium tube further includes a binder, wherein a volume ratio of the powder to the binder is (35 to 60): (40 to 65), preferably ( 40 to 45): (55 to 60).

Wherein, the binder is preferably one or more of ethylene and vinyl acetate copolymer (EVA), high density polyethylene (HDPE), stearic acid (SA) and paraffin wax (PW). In some embodiments of the invention, the binder is a mixture of ethylene and vinyl acetate copolymer (EVA), high density polyethylene (HDPE), stearic acid (SA), and paraffin (PW), wherein ethylene The volume ratio of the copolymer of vinyl acetate, high density polyethylene, stearic acid and paraffin is (9-20): (7-10): (8-15): (55-76), preferably (10-18) ): (8 ~ 9): (10 ~ 12): (60 ~ 70).

There are three crystal forms of pure zirconia in different temperature ranges. The change of crystal form is reversible, and it is accompanied by volume change. It is easy to cause cracking of the tube during cooling after sintering, so some stabilizers will be added to form replacement. The solid solution makes the crystal form transition irreversible. The zirconium tube provided by the present invention adds magnesium oxide as a stabilizer to the raw material, and the low-priced magnesium ion replaces the high-priced zirconium ion, in order to maintain the electrical neutrality of the molecule, in the anion (oxygen ion) The formation of holes at the junction provides an advantageous condition for the migration of oxygen ions, which is also the basis of MgO-ZrO ₂ as the oxygen ion solid electrolyte.

The content of MgO, the thermal shock resistance of the zirconium tube, and the shrinkage of the zirconium tube after sintering all affect the ionic conductivity and electronic conductivity of the zirconium tube and the performance, which in turn affects the performance of the entire oxygen battery. The invention has good thermal shock resistance performance by controlling the addition amount of MgO and using a specific kind of adhesive, and has low and stable electronic conductive characteristic oxygen partial pressure and dense microstructure ( Prevent oxygen leakage).

The method for preparing the zirconium tube of the present invention is not particularly limited, and a method for preparing a zirconium tube known to those skilled in the art may be used. In the present invention, the method for preparing the zirconium tube is preferably:

The powder and the binder are sequentially subjected to kneading, injection, degreasing, and sintering to obtain a zirconium tube.

The present invention first kneads the powder and the binder to obtain a mixture. In the present invention, the kneading temperature is preferably from 110 ° C to 200 ° C, more preferably from 120 ° C to 180 ° C, and the kneading time is preferably from 3 to 8 hours, more preferably from 4 to 7 hours.

In the present invention, the three-stage temperature of the injection is preferably 160-180 ° C, 120-160 ° C, 110-150 ° C; the three-stage pressure of the injection is 110-130 bar, 90-109 bar, 40-58 bar, respectively. .

The degreasing temperature is preferably 160 to 600 ° C, more preferably 200 to 500 ° C; the degreasing time is preferably 60 to 100 h, more preferably 70 to 90 h; and the sintering temperature is preferably 1400 to 1900 ° C. More preferably, it is 1500 to 1800 ° C; the sintering time is 2 to 10 h.

The oxygen battery provided by the present invention further includes a reference electrode disposed at the bottom end of the zirconium tube, and the reference electrode is the reference electrode for the oxygen battery sensor provided by the present invention, and the raw material type and preparation method are not performed here. Narration. The amount of the reference electrode added in the oxygen battery sensor is preferably from 30 to 150 mg, more preferably from 40 to 120 mg.

The oxygen battery sensor provided by the present invention further includes an alumina powder layer disposed inside the zirconium tube and above the reference electrode. The amount of alumina added to the alumina powder layer is not particularly limited, and the reference electrode can be covered.

The oxygen battery sensor provided by the present invention further includes a metal wire penetrating through the reference electrode and the alumina powder layer, the metal wire is in contact with the bottom end of the inside of the zirconium tube at one end, and the other end extends to the zirconium Outside the tube. The type of the metal wire of the present invention is not particularly limited, and a metal wire known to those skilled in the art may be used. In the present invention, a molybdenum rod or an iron ring is preferably used.

In the present invention, the oxygen battery is preferably prepared as follows:

The reference electrode powder and the alumina powder are sequentially added to the zirconium tube, and then the metal wire is inserted into the reference electrode powder and the alumina powder, and finally sealed with cement to obtain an oxygen battery.

The reference electrode provided by the present invention adds MnO, CoO and NiO to the Cr+Cr ₂ O ₃ system to make the electrode powder highly reactive and has a large effective surface area. The oxygen battery sensor prepared by using the reference electrode has a fast response speed, a small measurement temperature deviation, and is applicable to both high and low oxygen environments.

In order to further understand the present invention, a reference electrode for an oxygen battery sensor, a method for preparing the same, and an oxygen battery sensor provided by the present invention will be described below with reference to the embodiments, and the scope of the present invention is not limited by the following examples.

Example 1

1. Preparation of zirconium tube

(1) Raw material composition:

Powder as a percentage of total volume: 41%

The specific composition of the powder is as follows:

70wt% ZrO ₂ ;

10wt% HfO ₂ ;

10wt% CaO;

5 wt% of Y ₂ O ₃ ;

5 wt% of MgO.

Adhesive as a percentage of total volume: 59%

The specific composition of the adhesive is as follows (volume percent):

15% EVA;

8% of SA;

10% HDPE;

67% of PW.

(2) Preparation method

The above powder and binder are kneaded, injected, degreased and sintered to obtain a zirconium tube.

Among them, the mixing temperature was: 172 ° C, and the time was 7 h.

The three temperatures of injection are: 180 ° C, 160 ° C, 150 ° C;

The three injection pressures were 110 bar, 90 bar, and 55 bar, respectively.

The degreasing temperature was 160 °C in the early stage and 460 °C in the later stage, and the total time was 80 hours.

The sintering temperature was 1900 ° C and the temperature was kept for 2 h.

(3) Performance test

1 Test method: The above zirconium tube was immersed in molten steel for a residence time of 10 s, and then the zirconium tube was inspected for cracks and defects, and the entire oxygen content test was successfully completed.

Test results: The above zirconium tube did not produce cracks and defects, and the entire test process was completed without affecting the test results.

2 The zirconium tube used once was broken, and the section was observed to have oxygen permeation. If there is no oxygen permeation, the section is clean white; if there is oxygen permeation, there are gray or dark impurities in the section.

As a result of the test, the cross section was clean white, demonstrating that there was no oxygen permeation, and the zirconium tube provided by the present invention was dense in texture.

2, reference electrode powder

(1) Raw material composition (% by mass)

Cr(40%)+Cr ₂ O ₃ (30%)+MnO(10%)+CoO(10%)+NiO(10%)

(2) Preparation method

The above electrode powder raw materials were ball milled and mixed. The ball milling process is as follows: the mixed powder is adjusted into a paste with an appropriate amount of ethanol solution, placed in a ball mill jar, and ball-milled at a rate of 300 r/min for 5 hours. The ball mill was vacuum dried and then ground for several hours, and then sieved and classified, and a mixed powder of 0.5 μm was selected. . The powder sample was placed in a quartz glass tube and vacuum sealed. It was placed in a high-temperature heat treatment furnace, heated to 1400 ° C at a heating rate of 3 ° C / min, and kept for 3 h, and pre-heat treated and pulverized to obtain a reference electrode powder.

(3) Performance test

The above reference electrode powder was subjected to an electron microscope scanning test, and the results are shown in FIG. 1. FIG. 1 is an electron micrograph of the reference electrode powder prepared in Example 1.

It can be seen from Fig. 1 that the reference electrode prepared by the invention has a good particle size distribution range and a large specific surface area.

3. Preparation of oxygen battery sensor

30 mg of reference electrode powder and alumina powder were added to the zirconium tube, and the molybdenum rod was inserted and sealed with a quick-drying cement to obtain an oxygen battery.

An oxygen cell sensor is prepared by assembling a thermocouple, a mud head, a protective paper tube, and the above oxygen battery.

(1) The performance of the oxygen battery sensor was tested under high oxygen concentration conditions, and the measurement was performed twice in succession, wherein the oxygen potential response time was <4 s. The specific results are shown in Table 1, Figure 2 and Figure 3. Among them, Table 1 shows the performance test results of the oxygen battery sensor under high oxygen concentration conditions.

Table 1 Performance test results of oxygen battery sensors under high oxygen concentration conditions

Continuous test sequence number	Temperature (°C)	Oxygen potential (mV)	Oxygen concentration (ppm)
1	1644.5	157.5	405.4
2	1645.5	155.8	399.1

As can be seen from Table 1, in the continuous test, the temperature deviation was only 1 ° C, the oxygen content deviation was only 6.3 ppm, the deviation was within 10%, and as can be seen from Fig. 2 and Fig. 3, the response was very rapid.

2 is a graph showing the performance test results of the oxygen battery sensor under the high oxygen concentration condition prepared in Example 1, and FIG. 3 is a graph showing the performance test results of the oxygen battery sensor under the high oxygen concentration condition prepared in Example 1. Figure 2 is the first test result chart of two consecutive tests, and Figure 3 is the second test result chart of two consecutive tests.

In Figures 2 and 3, the abscissa represents the test time (t) in s; the left ordinate represents the oxygen potential (EMF) in mV, and the right ordinate represents the temperature (TEMP) in °C. In the two curves in Fig. 2 and Fig. 3, the solid line indicates the change in temperature with the change of the test time, and the broken line indicates the change in the oxygen potential with the change of the test time. The test curve in the figure is stable and the result is reliable.

The TEMP on the right side of the curve in Figures 2 and 3 represents the final test result, namely the molten steel test temperature; TVar represents the temperature test variance; EMF represents the final oxygen potential value of the oxygen battery; EVar represents the oxygen potential test variance; a(O) represents Active oxygen content in molten steel, C represents the carbon content in molten steel.

Among them, the TEMP in FIG. 2 is 1644.5 ° C, the TVar is -1.4 ° C, the EMF is 157.5 mV, the EVar is 1.7 mV, the a (O) is 405.4 ppm, and the C is 0.068%. In Figure 3, TEMP is 1645.5 ° C, TVar is 1.6 ° C, EMF is 155.8 mV, EVar is 3.1 mV, a (O) is 399.1 ppm, C is 0.069%.

(2) The performance of the oxygen battery sensor was tested under low oxygen concentration conditions, and the oxygen potential response time was <4 s. The specific results are shown in Table 2, Figure 4 and Figure 5. Among them, Table 2 shows the performance test results of the oxygen battery sensor under low oxygen concentration conditions.

Table 2 Performance test results of oxygen battery sensors under low oxygen concentration conditions

Continuous test sequence number	Temperature (°C)	Oxygen potential (mV)	Oxygen concentration (ppm)
1	1509.7	-81.6	5.7
2	1509.2	-82.7	5.6

As can be seen from Table 2, in the continuous test, the temperature deviation was only 0.4 ° C, the oxygen content deviation was within 10%, and it can be seen from Fig. 4 and Fig. 5 that the response was very rapid.

4 is a graph showing the performance test results of the oxygen battery sensor under the low oxygen concentration condition prepared in Example 1, and FIG. 5 is a graph showing the performance test results of the oxygen battery sensor under the low oxygen concentration condition prepared in Example 1. Figure 4 is a graph of the first test results of two consecutive tests, and Figure 5 is a graph of the second test results of two consecutive tests.

In Figures 4 and 5, the abscissa represents the test time (t) in s; the left ordinate represents the oxygen potential (EMF) in mV and the right ordinate represents the temperature (TEMP) in °C. In the two curves in Fig. 4 and Fig. 5, the solid line indicates the change in temperature with the change of the test time, and the broken line indicates the change in the oxygen potential as a function of the test time. The test curve in the figure is stable and the result is reliable.

The TEMP on the right side of the curve in Figures 4 and 5 represents the final test result, namely the molten steel test temperature; TVar represents the temperature test variance; EMF represents the final oxygen potential value of the oxygen battery; EVar represents the oxygen potential test variance; a(O) represents The active oxygen content in the molten steel, and Al indicates the acid-melted aluminum content in the molten steel.

Among them, in FIG. 4, TEMP is 1509.7 ° C, TVar is -1.8 ° C, EMF is -81.6 mV, EVar is -3.4 mV, a (O) is 5.7 ppm, and Al is 0.000%. In Fig. 5, TEMP is 1509.2 ° C, TVar is -1.8 ° C, EMF is -82.7 mV, EVar is -2.7 mV, a (O) is 5.6 ppm, and Al is 0.000%.

Example 2

1. Preparation of zirconium tube

(1) Raw material composition:

Powder as a percentage of total volume: 55%

The specific composition of the powder is as follows:

71wt% ZrO ₂ ;

10wt% HfO ₂ ;

12wt% CaO;

7 wt% of MgO.

Adhesive as a percentage of total volume: 45%

The specific composition of the adhesive is as follows (volume percent):

17% EVA;

12% SA;

8% HDPE;

63% of PW.

(2) Preparation method

The above powder and binder are kneaded, injected, degreased and sintered to obtain a zirconium tube.

Among them, the mixing temperature was: 170 ° C, and the time was 6 h.

The three temperatures of injection were: 178 ° C, 158 ° C, 146 ° C

The three injection pressures were 108 bar, 87 bar, 53 bar.

The degreasing temperature was 165 ° C in the early stage and 465 ° C in the late stage, and the time was 90 h.

The sintering temperature was 1600 ° C and the temperature was kept for 2 h.

(3) Performance test

1 Test method: The above zirconium tube was immersed in molten steel for a residence time of 10 s, and then the zirconium tube was inspected for cracks and defects, and the entire oxygen content test was successfully completed.

Test results: The above zirconium tube did not produce cracks and defects, and the entire test process was completed without affecting the test results.

2 The zirconium tube used once was broken, and the section was observed to have oxygen permeation. If there is no oxygen permeation, the section is clean white; if there is oxygen permeation, there are gray or dark impurities in the section.

As a result of the test, the cross section was clean white, demonstrating that there was no oxygen permeation, and the zirconium tube provided by the present invention was dense in texture.

2, reference electrode powder

(1) Raw material composition (% by mass)

Cr(50%)+Cr ₂ O ₃ (25%)+MnO(5%)+CoO(12%)+NiO(8%)

(2) Preparation method

The above electrode powder raw materials were ball milled and mixed. The ball milling process is as follows: the mixed powder is adjusted into a paste with an appropriate amount of ethanol solution, placed in a ball mill jar, and ball-milled at a rate of 300 r/min for 5 hours. The ball mill was vacuum dried and then ground for several hours, and then sieved and classified, and a mixed powder of 0.25 μm was selected. The powder sample was placed in a quartz glass tube and vacuum sealed. It was placed in a high-temperature heat treatment furnace, heated to 1300 ° C at a heating rate of 4 ° C / min, kept for 5 h, and pre-heat treated and pulverized to obtain a reference electrode powder.

(3) Performance test

The above reference electrode powder was subjected to an electron microscope scanning test, and the results are shown in FIG. 6. FIG. 6 is an electron micrograph of the reference electrode powder prepared in Example 2.

It can be seen from Fig. 6 that the reference electrode prepared by the present invention has a good particle size distribution range and a large specific surface area.

3. Preparation of oxygen battery sensor

65 mg of reference electrode powder and alumina powder were added to the zirconium tube, and the molybdenum rod was inserted and sealed with a quick-drying cement to obtain an oxygen battery.

An oxygen cell sensor is prepared by assembling a thermocouple, a mud head, a protective paper tube, and the above oxygen battery.

(1) The performance of the oxygen battery sensor was tested under high oxygen concentration conditions, and the measurement was performed twice in succession, wherein the oxygen potential response time was <4 s. The specific results are shown in Table 3, Figure 7 and Figure 8. Among them, Table 3 shows the performance test results of the oxygen battery sensor under high oxygen concentration conditions.

Table 3 Performance test results of oxygen battery sensors under high oxygen concentration conditions

Continuous test sequence number	Temperature (°C)	Oxygen potential (mV)	Oxygen concentration (ppm)
1	1646.8	163.8	450.3
2	1647.2	158.6	420.3

As can be seen from Table 3, in the continuous test, the temperature deviation was only 0.4 ° C, the oxygen content deviation was within 10%, and it can be seen from Fig. 7 and Fig. 8 that the response was very rapid.

7 is a graph showing the performance test results of the oxygen battery sensor under the high oxygen concentration condition prepared in Example 2, and FIG. 8 is a graph showing the performance test results of the oxygen battery sensor under the high oxygen concentration condition prepared in Example 2. Figure 7 For the first test result chart of two consecutive tests, Figure 8 is the second test result chart of two consecutive tests.

In Figures 7 and 8, the abscissa represents the test time (t) in s; the left ordinate represents the oxygen potential (EMF) in mV and the right ordinate represents the temperature (TEMP) in °C. In the two curves in Figs. 7 and 8, the solid line indicates the change in temperature with the change of the test time, and the broken line indicates the change in the oxygen potential as a function of the test time. The test curve in the figure is stable and the result is reliable.

The TEMP on the right side of the curve in Figures 7 and 8 represents the final test result, namely the molten steel test temperature; TVar represents the temperature test variance; EMF represents the final oxygen potential value of the oxygen battery; EVar represents the oxygen potential test variance; a(O) represents Active oxygen content in molten steel, C represents the carbon content in molten steel.

Among them, the TEMP in FIG. 7 is 1646.8 ° C, the TVar is -1.5 ° C, the EMF is 163.8 mV, the EVar is -3.2 mV, the a (O) is 450.3 ppm, and the C is 0.061%. In Fig. 8, TEMP is 1647.2 ° C, TVar is 1.5 ° C, EMF is 158.6 mV, EVar is -1.6 mV, a (O) is 420.3 ppm, and C is 0.066%.

(2) The performance of the oxygen battery sensor was tested under low oxygen concentration conditions, and the oxygen potential response time was <4 s. The specific results are shown in Table 4, Figure 9, and Figure 10. Among them, Table 4 shows the performance test results of the oxygen battery sensor under low oxygen concentration conditions.

Table 4 Performance test results of oxygen battery sensors under low oxygen concentration conditions

Continuous test sequence number	Temperature (°C)	Oxygen potential (mV)	Oxygen concentration (ppm)
1	1509.2	-82.7	5.6
2	1509.5	-82.5	5.6

As can be seen from Table 2, in the continuous test, the temperature deviation was only 0.3 ° C, the oxygen content was not deviated, and the deviation was within 1 ppm, and it can be seen from Fig. 9 and Fig. 10 that the response was very rapid.

9 is a graph showing the performance test results of the oxygen battery sensor under the low oxygen concentration condition prepared in Example 2, and FIG. 10 is a graph showing the performance test results of the oxygen battery sensor under the low oxygen concentration condition prepared in Example 2. Figure 9 is a graph of the first test results of two consecutive tests, and Figure 10 is a graph of the second test results of two consecutive tests.

In Figures 9 and 10, the abscissa indicates the test time (t) in s; the left ordinate indicates the oxygen potential (EMF) in mV, and the right ordinate indicates the temperature (TEMP) in °C. Figure 9 And in the two curves in Fig. 10, the solid line indicates the change in temperature with the change of the test time, and the broken line indicates the change in the oxygen potential as a function of the test time. The test curve in the figure is stable and the result is reliable.

The TEMP on the right side of the curve in Figures 9 and 10 represents the final test result, namely the molten steel test temperature; TVar represents the temperature test variance; EMF represents the final oxygen potential value of the oxygen battery; EVar represents the oxygen potential test variance; a(O) represents The active oxygen content in the molten steel, and Al indicates the acid-melted aluminum content in the molten steel.

Among them, in Fig. 9, TEMP is 1509.2 ° C, TVar is -1.8 ° C, EMF is -82.7 mV, EVar is -2.7 mV, a (O) is 5.6 ppm, and Al is 0.000%. In Fig. 10, TEMP is 1509.5 ° C, TVar is -1.6 ° C, EMF is -82.5 mV, EVar is -3.2 mV, a (O) is 5.6 ppm, and Al is 0.000%.

Example 3

1. Preparation of zirconium tube

(1) Raw material composition:

Powder as a percentage of total volume: 50%

The specific composition of the powder is as follows:

72wt% ZrO ₂ ;

9wt% HfO ₂ ;

8 wt% of Y ₂ O ₃ ;

11 wt% of MgO.

Adhesive as a percentage of total volume: 50%

The specific composition of the adhesive is as follows (volume percent):

20% EVA;

7% of SA;

7% HDPE;

66% of PW.

(2) Preparation method

The above powder and binder are kneaded, injected, degreased and sintered to obtain a zirconium tube.

Among them, the mixing temperature was: 165 ° C, and the time was 8 h.

The three temperatures of injection were: 175 ° C, 155 ° C, 143 ° C;

The three injection pressures were 112 bar, 92 bar, and 56 bar.

The degreasing temperature is 180 °C in the early stage and 550 °C in the later period, and the total time is 85 hours;

The sintering temperature was 1650 ° C and the temperature was kept for 2 h.

(3) Performance test

1 Test method: The above zirconium tube was immersed in molten steel for a residence time of 10 s, and then the zirconium tube was inspected for cracks and defects, and the entire oxygen content test was successfully completed.

Test results: The above zirconium tube did not produce cracks and defects, and the entire test process was completed without affecting the test results.

2 The zirconium tube used once was broken, and the section was observed to have oxygen permeation. If there is no oxygen permeation, the section is clean white; if there is oxygen permeation, there are gray or dark impurities in the section.

As a result of the test, the cross section was clean white, demonstrating that there was no oxygen permeation, and the zirconium tube provided by the present invention was dense in texture.

2, reference electrode powder

(1) Raw material composition (% by mass)

Cr(70%)+Cr ₂ O ₃ (25%)+MnO(2%)+CoO(2%)+NiO(1%)

(2) Preparation method

The above electrode powder raw materials were ball milled and mixed. The ball milling process is as follows: the mixed powder is adjusted into a paste with an appropriate amount of ethanol solution, placed in a ball mill jar, and ball-milled at a rate of 250 r/min for 5 hours. The ball mill was vacuum dried and then ground for several hours, then sieved and classified, and a mixed powder of 1 μm was selected. The powder sample was placed in a quartz glass tube and vacuum sealed. It was placed in a high-temperature heat treatment furnace, heated to 1250 ° C at a heating rate of 5 ° C / min, and kept for 4 h, and pre-heat treated and pulverized to obtain a reference electrode powder.

(3) Performance test

The above reference electrode powder was subjected to an electron microscope scanning test, and the results are shown in FIG. 11. FIG. 11 is an electron micrograph of the reference electrode powder prepared in Example 3.

As can be seen from Fig. 11, the reference electrode prepared by the present invention has a good particle size distribution range and a large specific surface area.

3. Preparation of oxygen battery sensor

100 mg of reference electrode powder and alumina powder were added to the zirconium tube, and the molybdenum rod was inserted and sealed with a quick-drying cement to obtain an oxygen battery.

An oxygen cell sensor is prepared by assembling a thermocouple, a mud head, a protective paper tube, and the above oxygen battery.

(1) The performance of the oxygen battery sensor was tested under high oxygen concentration conditions, and the measurement was performed twice in succession, wherein the oxygen potential response time was <4 s. The specific results are shown in Table 5, Figure 12 and Figure 13. Among them, Table 5 shows the performance test results of the oxygen battery sensor under high oxygen concentration conditions.

Table 5 Performance test results of oxygen battery sensors under high oxygen concentration conditions

Continuous test sequence number	Temperature (°C)	Oxygen potential (mV)	Oxygen concentration (ppm)
1	1650.8	162.1	453.8
2	1652.6	160.3	448.8

As can be seen from Table 3, in the continuous test, the temperature deviation was only 1.8 ° C, the oxygen content deviation was only 5 ppm, the deviation was within 10%, and as can be seen from Fig. 12 and Fig. 13, the response was very rapid.

12 is a graph showing the performance test results of the oxygen battery sensor under the high oxygen concentration condition prepared in Example 3, and FIG. 13 is a graph showing the performance test results of the oxygen battery sensor under the high oxygen concentration condition prepared in Example 3. Figure 12 is a graph of the first test results of two consecutive tests, and Figure 13 is a graph of the second test results of two consecutive tests.

In Figs. 12 and 13, the abscissa indicates the test time (t) in s; the left ordinate indicates the oxygen potential (EMF) in mV, and the right ordinate indicates the temperature (TEMP) in °C. In the two curves in Fig. 12 and Fig. 13, the solid line indicates the change in temperature with the change of the test time, and the broken line indicates the change in the oxygen potential as a function of the test time. The test curve in the figure is stable and the result is reliable.

The TEMP on the right side of the curve in Figures 12 and 13 represents the final test result, namely the molten steel test temperature; TVar represents the temperature test variance; EMF represents the final oxygen potential value of the oxygen battery; EVar represents the oxygen potential test variance; a(O) represents Active oxygen content in molten steel, C represents the carbon content in molten steel.

In Fig. 12, TEMP is 1650.8 ° C, TVar is -1.4 ° C, EMF is 162.1 mV, EVar is 2.8 mV, a (O) is 453.8 ppm, and C is 0.061%. In Fig. 13, TEMP is 1652.6 ° C, TVar is -1.9 ° C, EMF is 160.3 mV, EVar is -1.2 mV, a (O) is 448.8 ppm, and C is 0.062%.

(2) The performance of the oxygen battery sensor was tested under low oxygen concentration conditions, and the oxygen potential response time was <4 s. The specific results are shown in Table 6, Figure 14, and Figure 15. Among them, Table 6 shows the performance test results of the oxygen battery sensor under low oxygen concentration conditions.

Table 6 Performance test results of oxygen battery sensors under low oxygen concentration conditions

Continuous test sequence number	Temperature (°C)	Oxygen potential (mV)	Oxygen concentration (ppm)
1	1622.3	-249.3	1.3
2	1623.2	-229.4	1.7

As can be seen from Table 6, in the continuous test, the temperature deviation was only 0.9 ° C, the oxygen content deviation was only 0.4 ppm, the deviation was within 1 ppm, and as can be seen from Fig. 14 and Fig. 15, the response was very rapid.

14 is a graph showing the performance test results of the oxygen battery sensor under the low oxygen concentration condition prepared in Example 3, and FIG. 15 is a graph showing the performance test results of the oxygen battery sensor under the low oxygen concentration condition prepared in Example 3. Figure 14 is a graph of the first test results of two consecutive tests, and Figure 15 is a graph of the second test results of two consecutive tests.

In Figs. 14 and 15, the abscissa indicates the test time (t) in s; the left ordinate indicates the oxygen potential (EMF) in mV, and the right ordinate indicates the temperature (TEMP) in °C. In the two curves in Fig. 14 and Fig. 15, the solid line indicates the change in temperature with the change of the test time, and the broken line indicates the change in the oxygen potential as a function of the test time. The test curve in the figure is stable and the result is reliable.

The TEMP on the right side of the curve in Figures 14 and 15 represents the final test result, namely the molten steel test temperature; TVar represents the temperature test variance; EMF represents the final oxygen potential value of the oxygen battery; EVar represents the oxygen potential test variance; a(O) represents The active oxygen content in the molten steel, and Al indicates the acid-melted aluminum content in the molten steel.

Among them, in Fig. 14, TEMP is 1622.3 ° C, TVar is -1.5 ° C, EMF is -249.3 mV, EVar is -3.4 mV, a (O) is 1.3 ppm, and Al is 0.174%. In Fig. 15, TEMP is 1623.2 ° C, TVar is 1.5 ° C, EMF is -229.4 mV, EVar is -2.5 mV, a (O) is 1.7 ppm, and Al is 0.153%.

In the preferred embodiment of the present invention, it should be noted that those skilled in the art can also make several improvements and refinements without departing from the principles of the present invention. These improvements and refinements should also be considered as the present invention. The scope of protection.

Claims (10)

1. A reference electrode for an oxygen battery sensor, which is prepared from the following mass percentage components:

   40 wt% to 99.96 wt% of Cr;

   0.01 wt% to 30 wt% of Cr ₂ O ₃ ;

   0.01 wt% to 10 wt% of MnO;

   0.01% to 10% by weight of CoO;

   0.01% by weight to 10% by weight of NiO.
2. The reference electrode according to claim 1, which is prepared from the following mass percentage components:

   50% by weight to 80% by weight of Cr;

   10 wt% to 25 wt% of Cr ₂ O ₃ ;

   1 wt% to 8 wt% of MnO;

   1wt% to 8wt% CoO;

   1 wt% to 8 wt% of NiO.
3. A method for preparing a reference electrode for an oxygen battery sensor, comprising the steps of:

   Ball milling of 40 wt% to 99.96% by weight of Cr, 0.01 wt% to 30 wt% of Cr ₂ O ₃ , 0.01 wt% to 10 wt% of MnO, 0.01 wt% to 10 wt% of CoO, and 0.01 wt% to 10 wt% of NiO Mixing to obtain a mixed slurry;

   The mixed slurry is sequentially dried, ground, sintered, and pulverized to obtain a reference electrode for an oxygen battery sensor.
4. The preparation method according to claim 3, wherein the ball milling speed is 100 to 300 r/min, and the ball milling time is 5 to 10 h.
5. The preparation method according to claim 3, wherein the specific method of sintering is:

   It is heated to 1100-1400 ° C at a heating rate of 1 to 6 ° C / min, and kept for 3 to 6 hours.
6. An oxygen battery sensor comprising an oxygen battery, a thermocouple, a mud head and a protective paper tube, the characteristics of which In that, the oxygen battery includes:

   Zirconium tube

   a reference electrode disposed at an inner bottom end of the zirconium tube;

   An alumina powder layer disposed inside the zirconium tube and above the reference electrode;

   a metal wire penetrating through the reference electrode and the alumina powder layer, the metal wire is in contact with a bottom end of the inside of the zirconium tube, and the other end extends to the outside of the zirconium tube;

   The reference electrode is selected from the reference electrode for an oxygen battery sensor according to claim 1 or 2.
7. The oxygen battery sensor according to claim 6, wherein the zirconium tube is prepared from a powder and a binder, and the powder comprises the following components:

   70 wt% to 95 wt% of ZrO ₂ ;

   4wt% to 15wt% HfO ₂ ;

   0.5 to 20% by weight of a mixed powder of metal oxides, the mixed powder of the metal oxides including one or more of CaO, MgO, Y ₂ O ₃ and CeO ₂ .
8. The oxygen battery sensor according to claim 6, wherein a volume ratio of the powder to the binder is (35 to 60): (40 to 65).
9. The oxygen battery sensor according to claim 6, wherein the binder is one or more selected from the group consisting of ethylene and vinyl acetate copolymers, high density polyethylene, stearic acid, and paraffin wax.
10. The oxygen battery sensor according to claim 6, wherein the binder is selected from the group consisting of ethylene having a volume ratio of (9 to 20): (7 to 10): (8 to 15): (55 to 76). Mixture with vinyl acetate copolymer, high density polyethylene, stearic acid and paraffin.

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