[go: up one dir, main page]

EP0363749A1 - Procédé pour la déphosphoration de métaux en fusion par traitment avec de métaux alcalins et de métaux alcalino-terreux - Google Patents

Procédé pour la déphosphoration de métaux en fusion par traitment avec de métaux alcalins et de métaux alcalino-terreux Download PDF

Info

Publication number
EP0363749A1
EP0363749A1 EP89118010A EP89118010A EP0363749A1 EP 0363749 A1 EP0363749 A1 EP 0363749A1 EP 89118010 A EP89118010 A EP 89118010A EP 89118010 A EP89118010 A EP 89118010A EP 0363749 A1 EP0363749 A1 EP 0363749A1
Authority
EP
European Patent Office
Prior art keywords
alkaline earth
alkali
melt
metals
metal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89118010A
Other languages
German (de)
English (en)
Inventor
Alok Dr. Dr.-Ing. Choudhury
Gerhard Dr. Dr.-Ing. Brückmann
Wilhelm Dr. Dr.-Ing. Burgmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Balzers und Leybold Deutschland Holding AG
Original Assignee
Leybold AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Leybold AG filed Critical Leybold AG
Publication of EP0363749A1 publication Critical patent/EP0363749A1/fr
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/10—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals with refining or fluxing agents; Use of materials therefor, e.g. slagging or scorifying agents
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising

Definitions

  • the invention relates to a process for removing phosphorus from metallic melts by treating the melt with at least one metal from the group of the alkali and alkaline earth metals in a treatment tank in the presence of slag.
  • the ESR process is an extremely slow process with a high energy requirement and consequently only suitable for smaller quantities of metal.
  • the energy requirement it must be taken into account that electrodes must first be cast from the steel to be cleaned, which electrodes must subsequently be remelted continuously into blocks. Since this process must take place in a water-cooled mold, high energy losses to the cooling water are inevitable.
  • the invention is therefore based on the object of specifying a method of the type described at the outset which is distinguished by a high degree of efficiency or utilization rate of the alkali metal or alkaline earth metal used and in which the disposal problem of the slag containing the reaction products is also reliably solved.
  • the object is achieved according to the invention in the method mentioned at the outset by treating melts with an iron content of at least 50 percent by weight and contents of nickel, cobalt and copper of at most 30 percent by weight in the melt at a distance from the bath surface , which corresponds to at least half of the total bath height, by means of an inert gas, injects a particulate mixture of at least one of the alkali and alkaline earth metals mentioned and at least one halide of the same alkali or alkaline earth metal, the mixing ratio being chosen so that under the reaction conditions a Minimum of alkali or alkaline earth metal evaporates that the unreacted components of the mixture (alkali and alkaline earth metal and the halide or the halides of these metals) and the phosphides formed by the reaction of the alkali and alkaline earth metals in the slag located above the melt collects and thereby carries out further reactions between the alkali and alkaline earth metals and the iron-containing molten metal by bath movement
  • the melts in which the process according to the invention can preferably be used include, in addition to pure iron melts with less than 5% by weight of alloying elements, the melts of commercially available stainless chromium or chromium-nickel steels, such as, for example, No. 1.4300 (X 12 CrNi18 8), No. 1.4000 (X 6 Cr 13) and No. 1.4371 (X 12 CrMnNi 18 8 5).
  • Such chromium and / or manganese-containing steels cannot be freed from phosphorus by conventional freshening because due to the greater affinity of these metals for oxygen, a large part of the metals is lost through oxidation or combustion before the phosphorus reacts with oxygen.
  • phosphorus is usually removed by refining or oxidation.
  • the particulate mixture used for dephosphorization can either consist of a mixture of granules of the alkali and alkaline earth metals on the one hand and at least one halide of the same alkali or alkaline earth metal on the other hand, or of a granulate of a mixture in which the alkali or alkaline earth metal in the at least a halide of the same alkali or alkaline earth metal is dissolved.
  • the alkali and alkaline earth metals in question can be dissolved in their own halides in any proportions, and the alkali or alkaline earth metals evaporate from this melt far more poorly than if they were added to the iron-containing melt alone.
  • the phosphorus content can be reduced with the process according to the invention without noticeable erosion of chromium from the melt.
  • the alkali or alkaline earth metal is dissolved in the halide in question before being blown into the iron-containing melt, the solution is allowed to solidify and granulated, and the granules are blown into the iron-containing melt.
  • the size of the granules is not very critical; it is only necessary to ensure that the granulate is transportable by a gas flow which is fed to the blowing lance.
  • the mixing or solution ratio of alkali and alkaline earth metals to the corresponding halide is chosen between 1: 2 and 2: 1.
  • drops of the solutions of alkali and alkaline earth metals in their halides rise from the injection point below the molten bath level to the latter due to the given temperatures and in the process interact intimately with the melt.
  • other contaminating elements such as tin, lead, nitrogen, arsenic, antimony, bismuth, oxygen, sulfur, selenium and tellurium are also removed from the melt.
  • reaction products rise to the surface of the molten bath and collect in the top slag located there, which preferably consists of the oxides of calcium and aluminum or contains these oxides in substantial amounts. Is of particular advantage also the presence of an amount of 5 to 15 percent by weight magnesium oxide. It should be emphasized that such a slag in turn does not dissolve any alkali or alkaline earth metal and has no significant influence on the P content of the melt.
  • the alkali or alkaline earth metal also continues to participate in the reaction, namely through the inevitable bath movement caused by the blowing gas supplied mixing of the iron-containing melt and the top slag is effected.
  • the phosphine formed is converted into the oxide in question, at the same time forming phosphorus pentoxide.
  • Ca3P2 + 4 02 3 Ca0 + P205.
  • Ca0 and P205 can in turn be converted to calcium phosphate, which can be used as a fertilizer in agriculture.
  • the separated slag is kept under an inert gas atmosphere until the oxygen treatment.
  • FIG. 1 shows a melting unit 1, which is of no interest here and in which the melt to be cleaned is produced. From this melting unit, the melt is poured into a pan 2, which is provided with a bottom outlet 3, which can be closed by a slide valve 4, and with an inlet 5 for a purge gas (for example argon).
  • a purge gas for example argon
  • slag 6 (so-called head slag) based on Ca0-Al203 is added.
  • the pan 2 is closed by a lid 7 with a blowing lance 8.
  • the immersion depth of the blowing lance in the molten metal is at least 50% of the total bath height from the pan bottom to the melt / slag interface.
  • the blow lance 8 stands via a flexible line with a reservoir, not shown here, in connection with a granulate which is a mixture of calcium and calcium fluoride.
  • the blowing lance 8 is connected to an argon source, the connection being selected in such a way that the argon introduces a corresponding amount of the mixture of calcium-calcium fluoride into the metal melt 9.
  • the gas space above the slag 6 is connected to the environment via a filter, but this is not shown here for the sake of simplicity.
  • the gate valve 4 is opened after cleaning, so that the molten metal 9 flows as a melt jet 9a in a further pan 10.
  • the process is interrupted before the slag 6 (now provided with the reaction products of the impurities) has the opportunity to exit through the bottom outlet 3. It is important that the gas space 11 remains shut off from the atmosphere.
  • the gas space above the slag can either through the blowing lance 8 or through a special line 13 with an inert gas, for example, argon, too.
  • the pan 10 with the melt 9b can now be fed to a further treatment station, not shown here, in which a treatment such as vacuum degassing or vacuum oxygen decarburization is carried out.
  • a treatment such as vacuum degassing or vacuum oxygen decarburization is carried out.
  • FIG. 3 shows the state in which the pan 2 essentially contains only the slag 6.
  • the oxidation treatment of the slag described above is now carried out. It is important that the gas space 11 above the slag is still sealed off from the atmosphere.
  • dry oxygen is blown into the pan 2 through the blow lance 8 until all reaction products have been converted into the pure oxygen compounds of the impurities.
  • the still molten slag is discharged through the bottom outlet 3 into a slag bucket 12, in which it can easily solidify in the ambient air.
  • the slag can now be brought to a disposal site.
  • a converter an arc furnace or an induction furnace, for example, can serve as the melting unit 1.
  • a mixture of a production gas and the reactive mixture of the alkali and alkaline earth metals and their halides can also through the bottom inlet 5 be introduced.
  • Example 1 Treatment of a 30 ton melt:
  • the steel melt to be treated contains the following components after casting from the melting unit 1: 1% C; 18% Cr; 8.5% Ni; 0.07% P; 0.04% S.
  • 300 kg of a slag mixture of 150 kg Ca0 and 150 kg Al203 as top slag are given up.
  • the melt is rinsed vigorously for 3 minutes with an amount of argon of 50 l / min.
  • the freeboard of pan 2 is 1000 mm; the temperature of the steel is 1600 ° C.
  • the Ca-CaF 2 mixture is blown in.
  • a blowing time of 10 minutes and an average blowing rate of 12 kg / min a total of 120 kg Ca-CaF2 are blown into the melt.
  • the blowing of the cleaning substance was stopped and the reaction was completed after a further 5 minutes.
  • the metal was tapped into a second pan 10 at a temperature of 1550 ° C. according to FIG.
  • the analysis of the melt after completion of the reaction led to the following values: 1% C; 18% Cr; 8.5% Ni; 0.025% P; 0.02% S.
  • the still liquid slag in the first pan 2 was refreshed with the same blowing lance 8 with oxygen.
  • the lower end of the lance was at a distance of approx. 400 mm from the slag.
  • a strong floor flush of approx. 75 l / min led to a quick oxidation.
  • the blowing time was about 7.5 minutes. About one minute after the completion of the freshening, the treated slag could easily be tapped into the slag bucket 12.
  • Example 2 Treatment of a 50 ton melt:
  • the timing of the individual process steps corresponded to that in Example 1.
  • the steel melt to be treated contained the following components: 0.8% C; 20% Cr; 10% Ni; 0.06% P; 0.04% S.
  • the amount of top slag added during tapping was 600 kg and consisted of 50% Ca0 and Al203. 100 l / min of argon were introduced through the bottom inlet 5 to bring about a gas purge.
  • the initial temperature of the melt was 1600 ° C.
  • the blowing lance 8 was immersed in the melt to such an extent that its lower end was about 1000 mm below the bath level, which also corresponded to 50% of the bath height here. This was constantly Inert gas passed through the blowing lance.
  • a Ca-CaF2 mixture containing 50% Ca was blown in over a period of 14 minutes with an average amount per unit time of 15 kg / min, so that a total of 210 kg of the treatment mixture got into the melt.
  • the reaction was complete 5 minutes after the blowing had ended and the analysis of the melt gave the following values: 0.8% C; 20% Cr; 10% Ni; 0.020% P; 0.015% S.
  • the final temperature was 1550 ° C, which guaranteed a subsequent vacuum degassing.
  • the slag was treated in accordance with Example 1.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
EP89118010A 1988-10-07 1989-09-28 Procédé pour la déphosphoration de métaux en fusion par traitment avec de métaux alcalins et de métaux alcalino-terreux Withdrawn EP0363749A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3834164 1988-10-07
DE3834164 1988-10-07

Publications (1)

Publication Number Publication Date
EP0363749A1 true EP0363749A1 (fr) 1990-04-18

Family

ID=6364608

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89118010A Withdrawn EP0363749A1 (fr) 1988-10-07 1989-09-28 Procédé pour la déphosphoration de métaux en fusion par traitment avec de métaux alcalins et de métaux alcalino-terreux

Country Status (2)

Country Link
EP (1) EP0363749A1 (fr)
JP (1) JPH02217411A (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2520841A1 (de) * 1974-05-09 1975-11-20 Nippon Steel Corp Verfahren zur entphosphorung und denitrifizierung einer leicht oxidierbare komponenten enthaltenden legierung
DE2629020B1 (de) * 1976-06-29 1977-08-11 Nippon Steel Corp Verfahren zum entphosphorn von metallen und legierungen
FR2428672A1 (fr) * 1978-06-14 1980-01-11 Siderurgie Fse Inst Rech Procede de dephosphoration d'un bain d'acier en phase reductrice
US4435210A (en) * 1982-02-12 1984-03-06 Showa Denko Kabushiki Kaisha Refining agent of molten metal and methods for producing the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2520841A1 (de) * 1974-05-09 1975-11-20 Nippon Steel Corp Verfahren zur entphosphorung und denitrifizierung einer leicht oxidierbare komponenten enthaltenden legierung
DE2629020B1 (de) * 1976-06-29 1977-08-11 Nippon Steel Corp Verfahren zum entphosphorn von metallen und legierungen
FR2428672A1 (fr) * 1978-06-14 1980-01-11 Siderurgie Fse Inst Rech Procede de dephosphoration d'un bain d'acier en phase reductrice
US4435210A (en) * 1982-02-12 1984-03-06 Showa Denko Kabushiki Kaisha Refining agent of molten metal and methods for producing the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
STAHL UND EISEN *

Also Published As

Publication number Publication date
JPH02217411A (ja) 1990-08-30

Similar Documents

Publication Publication Date Title
DE3024697A1 (de) Verfahren und vorrichtung zur herstellung legierter oder unlegierter reaktiver metalle
DE1941282A1 (de) Verfahren zur Veredelung von Stahl durch Umschmelzen in einem Plasma-Lichtbogen
DE3809477C2 (de) Verfahren zum Entfernen von Schwefel aus Kupferschmelzen
DE3045180C2 (de) Verfahren und Vorrichtung zur Herstellung einer hochchromhaltigen Roheisenschmelze als Zwischenprodukt für die Herstellung von hochchromhaltigem Stahl
EP0053848B1 (fr) Procédé d'insufflation de gaz à teneur élevée en oxygène dans un bain de fusion de métaux non-ferreux
DE1583260B1 (de) Verfahren zur Herstellung nichtrostenden Stahls mit 14 bis 18% Chrom
DE2255977A1 (de) Verfahren zum raffinieren von metallischem kupfer
DE3136058C1 (de) Verfahren zum Gewinnen eines CO-reichen Abgases beim Frischen von Stahlschmelzen
DE3426736C2 (fr)
DE2803940C2 (de) Verfahren zum Vakuumfrischen hochchromhaltiger Stähle mit äußerst geringen Kohlenstoff- und Stickstoffgehalten
EP0363749A1 (fr) Procédé pour la déphosphoration de métaux en fusion par traitment avec de métaux alcalins et de métaux alcalino-terreux
DE3931656A1 (de) Verfahren zum entfernen von phosphor aus metallischen schmelzen durch behandeln mit alkali- und erdalkalimetallen
DE4033182C2 (fr)
DE2629020C2 (de) Verfahren zum entphosphorn von metallen und legierungen
DE2559188C2 (de) Verfahren zur Entschwefelung von Stahlschmelzen
DE573114C (de) Verfahren zur Gewinnung von Platinmetallen
EP0343378A1 (fr) Procédé pour l'élaboration, à partir de leurs oxydes, de métaux tels que le titane, le zirconium, le chrome, le samarium ou le néodyme
DE2829372A1 (de) Verfahren zum herstellen von yttrium- metall und von dessen legierungen
DE19918766C2 (de) Verfahren zur Entfernung von Verunreinigungen aus Schmelzen von Metallen oder Legierungen
DE2509650C2 (de) Verfahren zur schmelzmetallurgischen Herstellung von vanadinhaltigen Legierungen
AT337238B (de) Verfahren zur entschwefelung von stahlschmelzen
DE2114123A1 (de) Herstellung von Metallen aus metallhaltigen Werkstoffen
DE648244C (de) Verfahren zur Entfernung von Verunreinigungen aus Kupfer mit Ausnahme von Sauerstoff
DE2656812A1 (de) Verfahren zum fortlaufenden frischen von geschmolzenem eisen
DE1758455C3 (de) Verfahren zum Frischen von legierten kohlenstoffhaltigen Eisenschmelzen

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB LU SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19901019