DE6925747U - ELECTRODE FOR DETERMINING OXYGEN ION ACTIVITY IN MOLTEN METALS. - Google Patents

Description

British Steel Corporation, London SW l / England, 33 Grosvenor Place

Electrode for determining the oxygen ion activity in molten metals.

The subject of the invention is the electrochemical determination of the ions in molten metals, in particular the determination of the oxygen ions! activity in molten metals, for example in molten iron or steel. [

It is known that for the electrochemical determination of the ions in j molten metals and in particular for determining the; Oxygen ions a contact electrode in the melted, Immerse material and a reference electrode in the form of a tube closed at the end, which consists of a for the to be determined Ion-permeable material consists, and which is filled with a reference electrolyte, in which electrolyte Another contact electrode is immersed in the tube.

The resistance of such an electrode depends on the resistance of the pipe itself, and thereby the Selection from the substances that can be used for this purpose and that have sufficient mechanical strength under the conditions of use have, severely limited "

In addition, many known electrode cells are used as a cover material a gas is used which is introduced under constant pressure inside the tube constituting the electrode will. Such electrodes require a constant supply of gas,

where oxygen is usually used and it is necessary to supply the gas to the measuring point under constant pressure.

The invention relates to an electrode for determining the
. Oxygen ion activity in molten ketals, according to
According to the invention, the electrode consists of a metal-ceramic body which is connected to an electrical lead, and
which, immersed in the melt, consists of a surface layer
an electrolyte material that is permeable to oxygen ions. The arrangement can either be such that
the metal-ceramic body is provided with a surface layer
is used as an electrolyte material when immersed in the melt,
which is permeable to oxygen ions acts or so that when the metal-ceramic body is immersed in the melt, a layer of an electrolyte material that is permeable to oxygen ions forms on its surface. As for oxygen | Ion-permeable electrolyte material are possible, aluminum oxide, magnesium oxide, zirconium oxide or a mixture of yttrium and thorium oxide. The metal-ceramic material can be molybdenum alumina ceramics, molybdenum zirconia ceramics, molybdenum thorium oxide ceramics, molybdenum thorium oxydyttrium oxide ceramics or molybdenum; be magnesium oxide ceramic. Other metal-ceramic materials can also be used for the electrodes according to the invention.

Metal-ceramic materials are made by mixing the
finely divided metal with a heat-resistant metal oxide
or a mixture of such oxides and heating the mixture to a temperature so high that a heat-resistant one
Body arises. As an electrical lead to the electrode
According to the invention, a leg of a thermocouple
to serve. The Metallkera "iikkörper suitably has the shape of a j at one end closed tube, and in this case, the '· thermocouple may be located within this tube. The j metal lead may be electrically connected to the metal-ceramic body
be conductively connected, by means of molybdenum powder, which sinters together when immersed in the melt.

The electrodes according to the invention indiu.g]: önn ⁿ n in a converted f ;. ^: .;. ',, .i: - ■.: -. vw.v a 3 eh ^.: '.It er πι', hit :: c bent:! .ndigem putter ordered, ir. ic r oi:; o be used, ia. at least one electrode in I τ er

is. Advantage hold! Can also be several

Such electrodes ± "in the uterus are embedded staggered against one another at different depths, so that when the putter is removed due to wear, at least one of the electrodes is always used for measurement.

Lei performing the !! es :: 'i: .g with an electrode after the The present invention is, besides the I.e ^ electrode, another second electrode, ils contact electrode, inserted into the melt Ui.d the electromotive force (EIlK) between the ne.electrode and the contact electrode as I ate for the ion activity the melt -measure.

In the case of the oxygen ion activity in molten steel, old-. Hot electrode a rod or a tube made of fiolybdenum- ^: .lur-; ir.iumo: .. yjkeramik serve, which on its r ^: ub (. "En surface mi ζ -? Ine: .i .i.luminiumo:; ydüberzu ~ is provided.:. 'fi: .i immersion in a molten iron or steel, the aluminum oxide layer acts between the steel and ue: .. body made of polybdenum clay As ele]: trolyte of the! ■! ßelectrode cell luni the vezu-suontane. "is the holybden alumina ceramics is st. A contact electrode is inserted into the wrought iron and connected to the keiielelectrcde made of colybdenum aluminum oxide ceramics via a killivoltmeter. Measurement of the tension that arises depending on the acidic ion content of the molten steel. When using a rod or tube made of ilolybdenum aluminum oxide ceramic, it is possible to immerse the rod or tube directly into the steel, whereby the molybdenum is extracted the surface layer of the rod egg liohres out is dissolved, 10 because a layer of aluminum oxide remains, which forms the electrolyte, ° = o dai, '> a hot cell is formed. 3ei

der 3>ef.;'cir.r ..: iui:.; aer Gauerstoffi a: egg.activity in molten steel v'ir.'i hence the otcb or aas]; ear immersed in the ^ esch ::: olzenen '■ tahl and either; ui the', 'ana of the container or by means of' .- ¹ IHC ^; n: aerer>.-Eoi-: r.etor. Device "attached, Das ::: etail]: he": i: i: -che Hctevial is connected to the one branch of a KiIIivoltneters, desce :; other clergy r.it the molten steel over a graphite or 3tau rod, which forms the contact electrode, in Verbir; -;:. - -does. The voltage that occurs depends on the ::. : \ ateri.il,: as that of the Iietallker; a: iikkör:; he consists and of the Sauo ^ L-tuffVehait of the melt.

J ± e Jle.:troaen tore the rfir.dun: have the. Advantage that in i: \ all one I ^; esch ^: 'di ^ uni :: the i .e tallicerai ikschicht the ketall from the metalkeraniüchon -itoi'f ai: aer surface;'. before it is released, so that a cb -. ;; - fl. '"chenscl : icht -i-up the oxide of the met. '. illkera:.: isehen "..atorial ^ ent; vta:, t and on this'., ^r eise the cell is regenerated, so that., ^ ie \, is still usable.

Auuführungsbeispiele the st The fen and it _b lJrfindun - are described in bargain forming the basis of the r '^ acids.

Figure 1 shows schematich a Lil ^ trode according to the invention with the measuring arrangement.

Pigur 2 shows another embodiment of an electrode the invention.

Figure 3 shows a further .lUs ⁴ .lihrunrtsform an electrode according to the invention.

Figure 4 shows a Säch curve.

FIG. 5 shows a graph of the result of a rlessung Oxygen ion activity of a melt compared to temperature.

Figure ο shows a section through the wall of a converter, in the mutually staggered electrodes according to the invention

f \ C \ r ~ * si μ ι + λ

are embedded.

The cell shown in Figure 1 consists of rough, the tube Io, which is closed at one end, of kolybdenum aluminum oxide core, which has an outer diameter of Io mn and a ¹ V ¹ thickness of 2 mm. The outer surface of the metal ceramic body is covered with a layer 11 of aluminum oxide which has a thickness of 0.5 mm and which forms electrolytes. A supply line 12 is electrically conductively connected to the Eetallkeranikrohr Io, and this electrode can be arranged in the permanent lining of a pan or a freshness, in which the melt whose oxygen ion activity is to be determined is located. Jie .- 'ulei cu ·: ■ 12 is a Llillivoltmeter 13, z is a Eöhrenvoltmeter u ± / can esistance be high Eingangsv, connected to the contact electrode 14 (3 mm ca) an iron rod of l / ü " can its diameter to carry out the - essunr / ith the electrode from the v.!. earrings Io with the surface layer 11 is made and placed in non-rui ι .IRR melt the contact electrode 14 and di · - Po lentialdif conference-acres beiaer . ilektroden means of VoI ■ ': ·; ters I ^ measured with the -enessene opannun · a,:. iin \; ice -vdi'.. the Sauerstoffai: ^TIVIT:; .t der] contained in the Gefäb -. -Jci.nolzo;: ibt.

The in - '"ι; ur 2 -represented .1ο..Λ: ■ ·. ..?. Is made from a tube of I \ olybdenum' ⁱ .lUi'.ir.ium..eramik (durarii os material is in the trade you can get it under the trade name: unen "I; etamic 562" der Ilor, -anite .iesearch .0 Development Lt. is located. The electrical connection with the de;., Roiir 2o is made by a hollybden wire 22 which is inserted into the tube, v / whether the nolybde: " Establish electrical contact between the pipe 2o and the supply line 22. The supply wire 22, in this case a Holybdbiidrakt, is currently a leg of a

Thermocouple 23, the second wire 24 of which is a molybdenum alloy with 41 wt / molybdenum.

The:, contact electrode that works as a second electrode together with the electrode shown in o / 'igur 2 is used again a steel rod of 1 / fcä "diameter. The electric one The voltage between the two electrodes is measured again with a tube voltmeter with a high input resistance.

To carry out a measurement, the ear 20 of the electrode shown in the figure was immersed in an aluminum oxide crucible of an electric high-temperature furnace. The crucible was filled with electrolyte iron powder, and the furnace atmosphere was hydrogen gas. The temperature v / urde increased to 1580 ⁰ C and melted the Siaen. The hydrogen atmosphere was replaced by nitrogen containing A> hydrogen. The electrode voltage was measured and a sample of the molten iron was taken. The oxygen content of the bath was then increased by adding iron oxide and then decreased again by adding graphite. After each addition, the melt was allowed to come to equilibrium and a sample was then drawn and the electrode voltage measured / has been corrected to determine the effect of carbon on the basis of an interaction coefficient of 0.13.

The analysis of the chimpanzee was as follows:

Carbon 0.0 ^v >0;'

Silicon less than 0.010 ; o

Manganese 0, whether ? ^J

Sulfur 0.01 !; Γ>

Phosphorus $ 0.007>

- 7 -

-Y-

The results of several such Voi'suchon were combined in id it resulted, äni'i they scattered a line which corresponds to the equation:

ELiK

-114 log

- 94,

v / whether ei 0 indicates the oxygen ionic activity. The scatter probably due to the indefinite drawing between your g-esant oxygen content, dor also the floating ones Oxygen particles includes and the oxygen activity, the exclusively through the oxygen dissolved in the liquid metal is conditional. The scatter -.uch can be traced back to the l'eil are on the hand in the accuracy of the Kessung the EI-IC and the analysis. The Bich curve obtained is in Figure 4 shown.

In practice it is expedient to use a more resistant form of the ^ lc.trode after the l-irfindun. ^, As shown in Pigur 3. The metal ceramic tube 2o here has a significantly greater thickness than in the embodiment according to i ⁽¹ i ~; ur 2. The open end of the tube is effectively clogged by means of the insulator 25, which is located between the inner surface of the tube 2o and the outer surface of the tube 2't> of the thermocouple is located. the assembly of the wires 22 and 24 of the thermocouple is as in the ..usfL.hrungsform by ^ iäPg

2.

The cell shown in Figure 3 was inserted into the './and of a basic Bessemer pear in order to measure the ionic activity in the converter during the Irish from high iron to steel. Molten iron and scrap were brought into a converter along with a batch of limestone. Oxygen and high pressure steam were, as in the procedure with. ■ or lower St>.> C-: stu T. common, lurcii; ie nozzles in .. o.icn des j.onvurters eijigeleit t, '..': '. :: rend the converter to

"JThinking" was, and be :. At the beginning of the frish reaction, the converter was tilted back for a period of about 12 limiter. With the cornfield tilted back, the Ziieanmer electrode dipped into it. with a contact electrode into the molten metal ur.a the BLK av / i see the contact electrode and the heating electrode was continuously monitored and recorded during the first blowing. At the end of the first blowing, the temperature was increased to 1600, the converter was tilted downwards and the slag was removed, and an additional Len: ei ^ alk was then added. Then a short Γ. durcngef achblasen ährt before the molten steel ε au was variables of the converter ~ e *.

? i ^for 5 shows a diagram of the chewing process of this process, where the oxygen ion is indicated as the ordinate and the time as abscesses. The> rdinaterjnaßotab on the right side of the -johuubildes. "Indicates the temperature.

The curve A and A are lines, the temperature curves and the curves 3 and ⁴ Β "'ie iauerstoffionen.uitivität as during the first and second blowing on ere Gz ^ ichnut \ ^r..

In practice, several electrodes with thermocouples can be stored in the '.'- nd of the converter, in the'., 'As shown in i'igur ό. The ' ^r .md 40 of the converter is provided on the inside Mi-: -ir.er refractory lining 41. Lccner 42 are provided in the '.'and 4o of the converter, which by means of displacement 4!?, Preferably from lethal or also outside refractory material are sealed. Four electrodes 44, -5, - '6 and 47 with thermocouples, as never shown in' igur 5 , were built into the lining 41 when it was manufactured. The first electrode is arranged ip.t ro , d'i ... ¹ it rn the inside something from the er., U?: X \ :; ru; r- -'1 iier-'Uür · .-: ':. _-i ·: - ^ \; ^ ite electrode

-; . ■ '-
. *. . > υ α ch Lr ... : ι. ι i β e de ier whether a en 'ann. U :; tc de η ■. c e noG "! ■: v / 'ärts staggered,:; o na.V. you further backwards.; staggered, ■ "1 ■ i i'.at "./ is also the ercte -.lek- - 10 - re .. ■ :. - / oiye d G ever drove 4th T Q-K »4- . jil J h iniiori'io.lb the fouc-rfeston. '.. us- estell'u i.; t. ' ■' u ^ i ' ^; .b je tr "., ^ e η, until the point η ac n !,> ■: .'- I lic V-. ¹ t V entry r . . ^: 'i Jur e .j Electrodes 46 and 47 are "e ^ eni-bor rd lic ..u.-ivuorun ^ 41 due to wear and tear ran - c: -laene i.etall 48, which is in the trode he ies trovien Ι- T ^ 4- _r . ton Lir.i i unu -; · + still other t them Inside of the Ketallkeranikrohr ·. Ί · ■ rei nd in J ¹ I - u 1 .; '' Ua from lex ¹ - υ d ar. '·' n.-i ne 3 0 I · '·· trode and the thermocouple ',,"' H i'f.a and des: .- etr 'ie , - earth. _ η ■ L) ° ^ . . , < ■■■ / i 'OSC :. rvK-'i ": 'jj ■ - ^ i ~ b ^' 4. ^^ V ^ ^^ ^^ L ^ Λ Nrf% Vj ^ '_V> vJ ^ - A Λ \ ^ ^ Li ** · \ ^ ^^' V ^ ^ »4 ^^ ^ Jb W
ZiGi -Jrreicher. this state, 44 after from rs or d "en ; ^ f η _. j. ^, ; ::::. 'iuerun; ^f up to the dash au .; t i as well . - ·> to: iekt Oh and • -ί - " _g ""r-»'', ^ t, ra-t but the second 21ek- eggs st, at all -c i j r. -d "■ ρ ν; earth. '. • .r -. Us and can be used for measurement e included ^ e . ο .. a J e S. i: .t, in zer ο :: continue until the i η - ■ 'J "I ic ese '. ^- eit from, etr-s ^ en is that too -3e : ...!. i.:e i now oar will, in front of the third and about chtej. , .η - '.' · et .: -de used in "leicher * ^r '.jise" Point ε ^ u before i fan dun ■ the electrodes after the tro ur.b uoriitoffionen activity of the ν, he. No. rs e that in the pan continually } or. the _ ice the advance of the fresh d i c r IT ■ / ■■; r öchu'Gz claims: v.-r 3 oils. I e s ρ

Claims (1)

- 10 protection requirements 1. Electrode for esti ^ rauir · the oxygen iojienuktivi: i. : eschmolzenen Iletallen, thereby: '; ekenn.ζeich: iet, da; ir; Ie consists of a metal ceramic body which i: i connects to an electrical supply line ;; is and there, immersed in the molten metal, a surface layer; made of an electrolyte material permeable to oxygen ions 2.?] Electrode according to claim 1, characterized ^ elzennzL'ichnet _? there..; the l.et-illkerar: .i]: ä: Body provided with a surface ::. chtjnc layer, which when :: immersed in .ii ·.? -chneize -.Is "'lektrolytr.at-irial, drx for r uorsto? JTio: · on v; rchli ^; .sci; T is, acts. 3. .. lt.;: Rojc r. ?. ..; ..) _ ruoh 1, h-,, ch .'ckci'.ngeichnc t , da ;. ' : ^ i cei. .iM: i., c; oj. ios. .e tallkeranikkiirpers into the melt a ^ chichi -us cine: ·: ΐ '\ τ ä;: u -..- ratofrio] ion dvruhlilssige :; » ■ -lchtrolyte material biliet. s electrode ". ch E.nspr ^ oi'i 1-? or J>, recognized by the fact that:. ¹ · that for .viuerstoEfionen d ^ irclilossi ^ e Elektrolytnatorial! at least one of the StoiTe .ELu: .iniumoxyd, Kajnesiui. ioxyd, üir;: oniu :: o; cyd or a 'Je;., isch before: E ::; contains oriuxioxyd and yttriuiioxyd. 'j. Electrode iv.ch a:;, iter ..nnrhche 1 eis 4, characterized da., Der: net-'ll>: era:.; Ische j.'ir ^ er from Lolybden-; i.luriiniuno: - : ydkora: ik, \ olybdänsirkoniunoxydkerariik, Eclybtihnthoriii.noxydkerai.iik, kolybdänthoriurnoxydyttriumoxydkerai.ik or üolrbdiinna,: nesiu :: io :: ' ^r dkera :: ii]: exists. ■:> . ". '.le :'ii'O.; e J. U:. O - Ί '' - draws ^: JM,:,: uie öle]: Lri ^ c ¹ : · ^. '! υlei Um; ·; there is one leg of the oinoK thermocouple. 7. Electrode according to one of claims 1 to 6, characterized in that the metal-ceramic body has a Äohr int closed at one end. 8. Electrode according to claim 7, characterized in that the thermocouple is located inside the ear. y. Electrode according to one of Claims 1 to 6, characterized in that the first metal supply line is in an electrically conductive bond with the metal-ceramic body with aolybdenum powder, which sintered together when immersed in the melt. 10. Electrode according to one of address 1 to 9 »In a converter vessel, characterized in that the electrode is embedded in the refractory lining of the converter. 11. Electrode according to claim IC, characterized in that that in the lining of the converter I have electrodes are staggered at different depths so that when the brick lining wears out, at least one of electrodes; ius aer. ilonverterfutter sticks out.