CN1403806A - Sulfur-detecting sensor capable of being used in in-situ detection - Google Patents

Abstract

The present invention belongs to the field of high temperature chemical and is one sulfur detecting sensor capable of being used in in-situ detection of sulfur content in high temperature molten steel and iron. It features the sensor with La beta-Al2O3 as electrolyte tube coated with one layer of La2O3S+Cr2O3 as supplement electrode material, reference electrode material mixture of La2O3+Cr+Cr2O3 and one Mo wire to constitute the cell; one thermocouple and one Mo wire set outside the electrolyte tube, and coated refractory material. The sensor can measure electric motive force and temperature in 20 sec and thus give out sulfur activity for directing production. It may be used in measuring the S content in molten iron, steel and other metal liquid.

Description

Sulfur measurement sensor capable of realizing online detection

The technical field is as follows:

the invention belongs to the field of high-temperature electrochemistry, and is particularly suitable for online detection of sulfur content in high-temperature molten steel or molten iron.

Background art:

the sulfur content of the melt is an important quality index in the steel-making and iron-making process, and workers operate according to an analysis result in smelting. However, chemical analysis or general instrumental analysis requires sampling and re-analysis, and the analysis speed is slow. Particularly in the rapid top-bottom combined converting, the end point judgment is only a few minutes, and the common analysis method can not meet the requirements. As long as 20 years ago, after the invention of a high-temperature oxygen sensor, namely an oxygen probe, people have started to research high-temperature sulfur sensors, but the high-temperature sulfur sensors are not successful because sulfides are unstable, and the high-temperature sulfur sensors can only be used in iron liquid with low oxygen content with several results.

The invention content is as follows:

the invention aims to solve the technical problem of how to realize on-line detection in the actual production process and quickly measure the sulfur content in molten steel or molten iron at high temperature.

A sulfur measuring sensor capable of realizing on-line detection is characterized in that the sensor uses La β -Al₂O₃The outersurface of the tube is coated with a layer of La for the solid electrolyte tube₂O₂S+La₂O₃Auxiliary electrode material, reference electrode material La is filled in the tube₂O₃+Cr+Cr₂O₃The mixture and a molybdenum wire lead wire are inserted into the center of the electrolyte tube to form a battery main body, a pair of thermocouples and a molybdenum wire are arranged outside the electrolyte tube, and the electrolyte tube is wrapped into a whole by using a temperature-resistant material, namely La β -Al₂O₃As an electrolyte, La₂O₂S+La₂O₃As an auxiliary electrode, La₂O₃+ Cr and Cr₂O₃For reference electrode, the specific cell expression is:

Mo|[S]_Fe|La₂O₂S，La₂O₃|Laβ-Al₂O₃|La₂O₃，Cr，Cr₂O₃|Mo

and (3) anode reaction:

and (3) cathode reaction:

and (3) battery reaction:

the theoretical calculation formula of sulfur activity is as follows: lna_[S]＝-23214E/T-79027/T+22.08。

The sensor can simultaneously measure the electromotive force and the temperature within 20 seconds, so that the activity of the sulfur can be immediately obtained. The activity can guide production, or the production control is carried out according to the conversion of the components of the molten steel into concentration, and the activity can be used for measuring the S content in molten iron, molten steel or other molten metals; the signal is output in millivolts (mV), and is easy to be connected with automatic control equipment; response time: 10-15 seconds; the use temperature is as follows: 1000-1750 ℃; in-situ measurements can be made; test range: 0.001-0.3% S;

calculating formula and testing accuracy:

calculation of iron melt at 1500 ℃: ln [% S]═ 5.578+0.01149E (mV) ± 0.0504

Calculation formula of molten steel at 1600 deg.C: ln [% S]═ 4.847+0.01075E (mV) ± 0.0728

And (3) comprehensive test error: delta +/-1.38%

The invention has the advantages of realizing on-line detection in the actual production process and quickly measuring the sulfur content in molten steel or molten iron at high temperature.

The specific implementation mode is as follows:

using a La β -Al with the diameter of 6mm and the length of 25mm₂O₃A solid electrolyte tube, the outer surface of which is coated with a layer of La₂O₂S+La₂O₃Auxiliary electrode material, reference electrode material La is filled in the tube₂O₃+Cr+Cr₂O₃The mixture and a molybdenum wire lead wire are inserted into the center of the electrolyte tube to form a battery main body, a pair of thermocouples and a molybdenum wire are arranged outside the electrolyte tube, and the electrolyte tube is wrapped by a temperature-resistant material to form a whole sensor.

TABLE 1 test results of sensors in iron bath at 1500 deg.C

[％S]	0.001	0.011	0.023	0.035	0.046	0.058	0.080	0.058
									Test 1(mV)	-114	95	154	189	212	235	268	379
Test 2(mV)	-119	100	152	192	218	240	270	383

TABLE 2 test results of sensors in molten steel at 1600 deg.C

[％S]	0.001	0.020	0.030	0.046	0.100	0.130	0.300
								Test 1(mV)	-188	92	119	171	226	264	338
Test 2(mV)	-180	98	120	170	230	268	343

[％S]Is the mass percentage.

Claims (1)

1. A sulfur measuring sensor capable of realizing on-line detection is characterized in that the sensor uses La β -Al₂O₃The outer surface of the tube is coated with a layer of La for the solid electrolyte tube₂O₂S+La₂O₃Auxiliary electrode material, reference electrode material La is filled in the tube₂O₃+Cr+Cr₂O₃The mixture and a molybdenum wire lead wire are inserted into the center of the electrolyte tube to form a battery main body, a pair of thermocouples and a molybdenum wire are arranged outside the electrolyte tube, and the electrolyte tube is wrapped into a whole by using a temperature-resistant material, namely La β -Al₂O₃As an electrolyte, La₂O₂S+La₂O₃As an auxiliary electrode, La₂O₃+ Cr and Cr₂O₃For reference electrode, the specific cell expression is:

Mo|[S]_Fe|La₂O₂S，La₂O₃|Laβ-Al₂O₃|La₂O₃，Cr，Cr₂O₃|Mo

and (3) anode reaction:

and (3) cathode reaction:

and (3) battery reaction:

the theoretical calculation formula of sulfur activity is as follows: lna_[S]＝-23214E/T-79027/T+22.08。