CN1616956A

CN1616956A - Method for making sulphur determining probe and auxiliary electrode

Info

Publication number: CN1616956A
Application number: CN 200410082888
Authority: CN
Inventors: 于景坤; 陈敏; 刘涛
Original assignee: Northeastern University China
Current assignee: Northeastern University China
Priority date: 2004-12-08
Filing date: 2004-12-08
Publication date: 2005-05-18
Anticipated expiration: 2024-12-08
Also published as: CN100344967C

Abstract

The present invention relates to making process of sulfur determining probe and auxiliary electrode, and belongs to the field of sulfur determining sensor technology. The sulfur determining probe includes solid oxygen ion electrolyte tube, Mo filament electrode inside the tube, high temperature cement and Al2O3 powder filled inside the tube, sulfide film attached to the outer or outer and inside surface of the tube, and Mo+MoO2/MoS2 powder or Cr+Cr2O3 powder as additive. The sulfide film is prepared via setting corundum tube sealed with high temperature cement and filled with H2S gas into high temperature furnace and reduction at 1000-1600 deg.c for 2.5-10 hr to form ZrS2+MgS/CaS film in the surface of the tube. The sulfur determining probe of the present invention has fast measuring speed and high measuring precision.

Description

Method for manufacturing sulfur determination probe and auxiliary electrode

Technical Field

The invention relates to a sulfur determination sensing element in a sulfur determination technology in the metallurgical industry, in particular to a sulfur determination probe for determining the sulfur content in molten metal and a manufacturing method of an auxiliary electrode thereof.

Background

The sulfur content is an important index for measuring the quality of pig iron. The accurate measurement and on-line control of the sulfur content in the molten iron are a vital task in the blast furnace ironmaking process. The traditional method for detecting the sulfur content has two types: chemical analysis and infrared sulfur determination. The method needs a complicated process of sampling, sample preparation and analysis, and cannot meet the requirement of automation of modern enterprises. Therefore, a method for rapidly and accurately measuring the sulfur content of molten iron is urgently needed. At present, one of the sulfur probes for measuring the sulfur content in molten metal comprises a solid electrolyte tube, electrodes arranged in the tube, high-temperature cement filled in the tube from top to bottom, and Al₂O₃Powder and Mo + MoO₂Powder layer, spraying a layer of sulfide or a mixture of sulfide and oxide on the surface of the tube as an auxiliary electrode, such as: the use of ZrO has been proposed by researchers₂(CaO) as solid electrolyte tube, CaO + CaS as auxiliary electrode, ZrO for Beijing university of science and technology₂A method for adding a CaS-CaO auxiliary electrode to a (MgO) electrolyte tube is used for researching and developing a sulfur determination probe for determining the sulfur content of molten iron, and Ca β -Al is also used by scholars₂O₃A sulfur determination probe which is a solid electrolyte and takes CaS as an auxiliary electrode, or La β -Al₂O₃A sulfur probe with CaS as auxiliary electrode as solid electrolyte, although β -Al₂O₃The high-temperature solid electrolyte has good high-temperature chemical stability and high ionic conductivity, but the response time of the probe is long, and the probe is not favorable for quickly measuring the sulfur content. The Baotou iron and steel institute comprehensively analyzes the thermodynamic feasibility of the metal liquid sulfur determination probe half cell. The results show that the product is represented by Y₂O₃Stabilized ZrO₂Solid electrolyte, Y₂O₂S is the sulphur determination probe half-cell of the auxiliary electrode, the performance is stable in the range of the sulphur content of the molten iron, the accuracy is high, and the error is small; adopted by Anhui university of industry Y₂O₃Stabilized ZrO₂As solid electrolyte, Y₂O₂S and Y₂O₃The mixture is used as an auxiliary electrode to assemble a sulfur determination probe.

The auxiliary electrode thin film layer of the probe has poor uniformity, low adhesion, low measurement precision and poor reproducibility.

Disclosure of Invention

Aiming at the defects, the invention aims to provide the sulfur determination probe which is high in sulfur content determination speed and high in sulfur determination precision.

The invention also aims to provide the sulfur determination probe which is low in production cost and high in yield.

The invention also aims to provide a sulfur determination probe which has strong auxiliary electrode adhesion, uniform adhesion density, large conductivity and small internal resistance of a battery;

the invention also aims to provide a manufacturing method of the auxiliary electrode, which can further ensure the quality of the sulfur determination probe.

The technical scheme adopted by the invention for solving the technical problems is as follows: mo wires used as electrodes are arranged in the center of a sulfur determination probe containing an oxygen ion solid electrolyte tube, and high-temperature cement and Al are sequentially filled in the tube from top to bottom₂O₃Powder and Mo + MoO₂Powder or Cr + Cr₂O₃The outer surface or inner and outer surfaces of the powder layer and the oxygen ion solid electrolyte tube are provided with a layer of compact sulfide film used as an auxiliary electrode, and the sulfide film is formed by ZrS₂And MgS or ZrS₂And a CaS material;

the manufacturing method of the auxiliary electrode comprises the following steps: firstly, filling Al into the oxygen ion solid electrolyte tube₂O₃Tamping the powder, plugging the powder by high-temperature cement, placing the powder into a corundum tube with one closed end, placing the corundum tube into a high-temperature furnace, and simultaneously injecting 0.04-0.4 NM into the corundum tube³H of/H₂S gas, the high-temperature furnace operates within 1000-1600 ℃, the reduction process is finished within 2.5-10 h of working time, thus a layer of compact sulfide is generated on the outer surface of the oxygen ion solid electrolyte,and the sulfur determination probe assembled by the tube has the following battery form:

Mo|Mo+MoO₂|ZrO₂(MgO)|ZrS₂-MgS|[S]_Fe|Mo(+)

or

Mo|Cr+Cr₂O₃|ZrO₂(MgO)|ZrS₂-MgS|[S]_Fe|Mo(+)

Or

Mo|Mo+MoO₂|ZrO₂(CaO)|ZrS₂-CaS|[S]_Fe|Mo(+)

Or

Mo|Cr+Cr₂O₃|ZrO₂(CaO)|ZrS₂-CaS|[S]_Fe|Mo(+)

Another manufacturing method of the auxiliary electrode comprises the following steps: directly placing an oxygen ion solid electrolyte tube into a corundum tube with one closed end, then placing the corundum tube and the oxygen ion solid electrolyte tube into a high-temperature furnace together for carrying out a vulcanization reduction reaction, wherein the working temperature of the reaction process is 1000-1600 ℃, the reduction time is 2.5-10 h, and simultaneously, 0.04-0.4 NM is injected into the corundum tube³H of/H₂S gas, thus a layer of compact sulfide is generated on the inner and outer surfaces of the oxygen ion solid electrolyte, namely a two-phase electrolyte tube is formed, and the sulfur determination probe assembled by the tube has the following battery composition:

Mo|Mo+MoS₂|ZrS₂-MgS|ZrO₂(MgO)|ZrS₂-MgS|[S]_Fe|Mo(+)

or

Mo|Cr+Cr₂S₃|ZrS₂-MgS|ZrO₂(MgO)|ZrS₂-MgS|[S]_Fe|Mo(+)

Or

Mo|Mo+MoS₂|ZrS₂-CaS|ZrO₂(CaO)|ZrS₂-CaS|[S]_Fe|Mo(+)

Or

Mo|Cr+Cr₂S₃|ZrS₂-CaS|ZrO₂(CaO)|ZrS₂-CaS|[S]_Fe|Mo(+)

The invention has the beneficial effects that: the sulfur determination probe has the advantages of simple structure, convenient manufacture, low cost, high speed of sulfur content determination, good reproducibility, stable work, high precision and long service life of the auxiliary electrode.

Drawings

The invention will be further explained with reference to the drawings

FIG. 1 is a schematic view of the structure of an external auxiliary electrode type sulfur determination probe;

FIG. 2 is a schematic diagram showing the structural principle of an auxiliary electrode type sulfur determination probe for internal and external surfaces;

FIG. 3 is a schematic diagram of the distribution of the auxiliary electrodes of FIG. 1;

FIG. 4 is a schematic diagram of the distribution of the auxiliary electrodes in FIG. 2;

FIG. 5 is a schematic diagram of a method for manufacturing the auxiliary electrode in FIGS. 2 and 3;

in the figure, 1 corundum tube, 2 high-temperature furnace, 3 oxygen ion solid electrolyte tube, 4 thermocouple, 5 Mo wire, 6 high-temperature cement and 7 Al₂O₃Powder, 8 auxiliary electrodes, 9 Mo + MoO₃Powder or Cr + Cr₂O₃Powder, 10 Mo + MoS₂Powder or Cr + Cr₂S₃And (3) pulverizing.

Detailed Description

The specific embodiment of the method for manufacturing the sulfur determination probe and the auxiliary electrode is as follows:

example 1: selecting an oxygen ion solid electrolyte tube 3 as a matrix, wherein the material of the matrix is ZrO₂And MgO or ZrO₂And CaO, the auxiliary electrode 8 is made by filling analytically pure Al calcined at 1700 ℃ into the oxygen ion solid electrolyte tube 3₂O₃Compacting and tamping the powder 7, sealing the opening of an electrolyte tube by using high-temperature cement 6, then placing the electrolyte tube into a corundum tube 1 with one closed end, placing the corundum tube into a high-temperature furnace 2, and simultaneously injecting H into the corundum tube 1₂S gas, carrying out the following chemical reaction:

or

The sulfide thin film used as the auxiliary electrode 8 is manufactured, and the following parameters are adopted:

example 2: selecting an oxygen ion solid electrolyte tube 3 as a matrix, wherein the material of the matrix is ZrO₂And MgO or ZrO₂And CaO, which is directly arranged in a corundum tube 1 withone closed end, the corundum tube is arranged in a high-temperature furnace 2, and H is injected into the corundum tube 1₂S gas, the reduction reaction is as follows:

or

when a sulfur determination probe is manufactured, an oxygen ion solid electrolyte tube 2 with an auxiliary electrode 8 sulfide film on the outer surface is used as a matrixThe center of the tube is provided with a Mo wire 5 used as an electrode, and the inside of the tube is filled with high-temperature cement 6 and Al in sequence from top to bottom₂O₃Powder 7 and Mo + MoO₂Or Cr + Cr₂O₃9, grinding; when the oxygen ion solid electrolyte tube 2 with sulfide film on the inner and outer surfaces is used as a matrix, high-temperature cement 6 and Al are sequentially filled in the tube from top to bottom₂O₃Powder 7 and Mo + MoS₂Or Cr + Cr₂S₃Powder 10.

The following groups can be used for the selection of parameters for manufacturing the sulfur determination probe:

Claims

1. a sulfur-determining probe is composed of oxygen ion solid electrolyte tube, Mo wire as electrode in the center of tube, and high-temp cement and Al filled in tube from top to bottom when sulfide film is on the surface of tube₂O₃Powder and Mo + MoO₂Or Cr + Cr₂O₃Pulverizing; when the inner and outer surfaces of the tube are provided with sulfide films, high-temperature cement and Al are sequentially filled in the tube from top to bottom₂O₃Powder and Mo + MoS₂Or Cr + Cr₂S₃The powder is characterized in that a layer of compact sulfide film used as an auxiliary electrode is arranged on the outer surface or the inner and outer surfaces of the oxygen ion solid electrolyte tube.

2. The sulfur probe of claim 1, wherein the probe is Mo + MoO₂Powder of Cr + Cr₂O₃Powder, Mo + MoS₂Powder or Cr + Cr₂S₃The mass ratio of the powder reference electrode is 85-98: 15-2.

3. The sulfur probe of claim 1 wherein the sulfide thin film is comprised of ZrS2 and MgS or ZrS2 and CaS materials.

4. The method of manufacturing an auxiliary electrode as defined in claim 1, wherein the oxygen ion solid electrolyte tube is first filled with Al₂O₃Plugging the powder with high temperature cement, placing the powder into a corundum tube with one closed end, placing the corundum tube into a high temperature furnace, and simultaneously injecting 0.04-0.4 NM into the corundum tube³H of/H₂S, the high-temperature furnace is operated within 1000-1600 ℃,and the reduction process is finished within 2.5-10 h of working time; the oxygen ion solid electrolyte tube can also be directly placed into a corundum tube with one closed end, then the tube is placed into a high-temperature furnace for carrying out the vulcanization reduction reaction, the working temperature in the reaction process is 1000-1600 ℃, the reduction time is 2.5-10 h, and 0.04-0.4 NM is injected into the corundum tube³H of/H₂And (4) S gas.