EP0094241B1 - Method of minimizing slag carryover - Google Patents

Method of minimizing slag carryover Download PDF

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Publication number
EP0094241B1
EP0094241B1 EP83302619A EP83302619A EP0094241B1 EP 0094241 B1 EP0094241 B1 EP 0094241B1 EP 83302619 A EP83302619 A EP 83302619A EP 83302619 A EP83302619 A EP 83302619A EP 0094241 B1 EP0094241 B1 EP 0094241B1
Authority
EP
European Patent Office
Prior art keywords
taphole
furnace
slag
metal
molten 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.)
Expired
Application number
EP83302619A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0094241A1 (en
Inventor
James Guy Bassett, Jr.
William Mellon Keenan
Sheldon Mcgarry
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.)
USS Engineers and Consultants Inc
Original Assignee
USS Engineers and Consultants Inc
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 USS Engineers and Consultants Inc filed Critical USS Engineers and Consultants Inc
Priority to AT83302619T priority Critical patent/ATE16945T1/de
Publication of EP0094241A1 publication Critical patent/EP0094241A1/en
Application granted granted Critical
Publication of EP0094241B1 publication Critical patent/EP0094241B1/en
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B3/00—General features in the manufacture of pig-iron
    • C21B3/04—Recovery of by-products, e.g. slag
    • C21B3/06—Treatment of liquid slag
    • 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
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C21C5/4653—Tapholes; Opening or plugging thereof

Definitions

  • This invention relates to a method of minimizing slag carryover during tapping of molten metal from a furnace.
  • a method of minimizing slag carryover upon draining molten metal from a furnace through a taphole comprising dropping onto the surface of molten slag and metal in said furnace, within an area above said taphole, a body having a density intermediate that of the molten metal and slag in said furnace and having a cross-section of minimum dimension greater than the maximum dimension of the cross-section of the opening of said taphole, draining molten metal from the furnace through the taphole opening, and then shutting off flow through said taphole so as to prevent carryover of slag onto the molten metal already tapped from the furnace, characterized in that said body has equilateral generally planar faces, the intersections of which are adapted to lodge in the taphole so that said body blocks 20 to 80 percent of the taphole opening when said body becomes lodged in said taphole opening, and the method includes monitoring the condition of the stream emerging from said taphole so as to obtain an indication of flaring of said stream when said body lodges in the taphole as
  • a body having a density of .12 to .22 pounds per cubic inch (3320 to 6090 kg/m 3 ) is preferred.
  • the body is of a material substantially indissoluble in the molten metal and slag.
  • the body preferably has a maximum dimension in any direction of five to twelve inches (13 to 30 cm) and is adapted to block 20 and 80 percent of a round taphole opening having a diameter of four to ten inches (10 to 25 cm) when an intersection of the faces of the body is lodged centrally therein.
  • the flaring stream acts as a signal to a furnace operator that slag will start to flow soon.
  • the operator may shut off flow, preventing slag carryover onto the metal in the ladle.
  • a primary advantage of the polyhedral-shaped device is that it does not become permanently lodged in the taphole and does not require burning with an oxygen lance in order to remove it from the taphole.
  • the body may have faces all of the same shape and size. A cuboid shape is preferred.
  • the body may be of refractory material having solid metal particles distributed therein to increase its density.
  • the metal particles may be shot or fibers or both, the latter serving to increase cohesive- ness of the body.
  • carbon steel shot is used whereas the fibers are of stainless steel composition.
  • a steelmaking converter 10 is shown having a refractory lining 12 and a taphole 14 located near the mouth 16 of the converter vessel.
  • the vessel is shown tilted downwardly from its normal upright position, so that molten metal 18 and slag 20 will drain therefrom.
  • a cube 22, having been dropped into the furnace contents above the taphole, is shown floating at the slag-metal interface during the tap and before being drawn into dotted position 24 by vortex action towards the end of the tap.
  • Figure 2 which is an enlarged section taken along the line II-II of Figure 1, the cube 22 is shown lodged in the taphole 14 and only partially blocking the taphole opening.
  • a cube 7 or 8 inches (18 or 20 cm) on each face has been found to work satisfactorily.
  • a seven inch (18 cm) cube is preferred. It will block about 40 percent of the cross-section of a six-inch (15 cm) diameter taphole.
  • the cube may be of any refractory material resistant to dissolution in the metal and slag, at least sufficiently to maintain the minimum dimensions necessary for lodging in the taphole. Castable refractory is preferred. Seven-inch (18 cm) cubes having a density of from 0.15 to 0.17 Ib/in 3 , (4150 to 4710 kg/m 3 ) have been used although any density between that of the slag and metal should suffice. For example, molten steel has a density of about 0.25 Ib/in 3 (6920 kg/m 3 ), whereas steelmaking slags have density of about 0.10 Ib/in 3 (2770 kg/m 3 ). Shown below are examples of mixtures used for making typical cubes:
  • the steel shot is of a type readily available and is used for increasing the density of the cube. Iron ore is used since it reacts with carbon in the steel bath and indicates where the submerged cube is located.
  • the stainless steel fibers tend to bind the refractory preventing the cube from breaking apart prematurely. Of course, it is desirable to completely dry the cubes in order to remove moisture which reacts with the metal, causing the cubes to crack and break.
  • the cube be dropped into a restricted area over the taphole so as to assure its being carried by fluid currents in the metal during tap into an area directly over the taphole so that it will lodge therein.
  • the angle of downward tilt of BOP or Q-BOP furnace at the end of tap if tilted so as to obtain the maximum rate of draining metal, varies from about 88° to 103° from vertical. The range of angles is due to various factors such as erosion of the furnace lining and solid slag or metal buildup at the furnace mouth. It has been found that reasonable estimates of the location of the taphole can be made by calculating the horizontal distance of the taphole from the furnace trunnions for various angles of tilt of the furnace.
  • the location of the taphole from the trunnions at the end of tap will vary over about four feet (1.2 m). Thus it has been found best to insert the cube in the middle of the calculated four-foot (1.2 m) distance. This can be accomplished by various means from floor level at a location adjacent the furnace mouth.
  • the cube should also be inserted into the furnace just before a vortex forms as the final portion of metal starts to drain out.
  • This time may be calculated from the estimated tonnage of metal contained in the furnace, the size and shape of the taphole in relation to metal bath so as to arrive at a critical tonnage of metal left in the furnace when vortexing will begin to occur.
  • This critical tonnage may be calculated for conventional steelmaking BOP and Q-BOP vessels from a formula. Normally, it is preferred to add the cube within a calculated time of one to two minutes before all of the metal has drained from the furnace.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
  • Furnace Charging Or Discharging (AREA)
  • Manufacturing Of Electric Cables (AREA)
  • Package Closures (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
EP83302619A 1982-05-10 1983-05-10 Method of minimizing slag carryover Expired EP0094241B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83302619T ATE16945T1 (de) 1982-05-10 1983-05-10 Verfahren zum verringern des mitlaufens von schlacke.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37680082A 1982-05-10 1982-05-10
US376800 1982-05-10

Publications (2)

Publication Number Publication Date
EP0094241A1 EP0094241A1 (en) 1983-11-16
EP0094241B1 true EP0094241B1 (en) 1985-12-11

Family

ID=23486561

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83302619A Expired EP0094241B1 (en) 1982-05-10 1983-05-10 Method of minimizing slag carryover

Country Status (15)

Country Link
EP (1) EP0094241B1 (ja)
JP (1) JPS5952189A (ja)
KR (1) KR840004786A (ja)
AR (1) AR231706A1 (ja)
AT (1) ATE16945T1 (ja)
AU (1) AU552735B2 (ja)
BR (1) BR8302426A (ja)
CA (1) CA1218846A (ja)
DE (1) DE3361476D1 (ja)
ES (1) ES522241A0 (ja)
FI (1) FI73739C (ja)
HU (1) HU187077B (ja)
IN (1) IN159857B (ja)
NO (1) NO831649L (ja)
YU (1) YU102483A (ja)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2188132B (en) * 1986-03-19 1990-06-13 Labate Michael D Slag retaining device for use in vessels such as converters, ladles or the like.
GB8712255D0 (en) * 1987-05-23 1987-07-01 Goricon Metallurg Services Plug members
NL8801231A (nl) * 1988-05-11 1989-12-01 Hoogovens Groep Bv Stop voor een staalconverter.
CN104117668B (zh) * 2014-08-01 2016-03-02 莱芜钢铁集团有限公司 一种大包浇注挡渣用挡渣塞及制备和挡渣方法
DE102017114859A1 (de) * 2017-07-04 2019-01-10 Sms Group Gmbh Vorrichtung zur selektiven Steuerung des Abstichvorgangs einer Schmelze aus einem Elektrolichtbogenofen

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2718389A (en) * 1950-11-17 1955-09-20 Electro Chimie Metal Skimmer for holding slag back during pouring metal
AT259602B (de) * 1965-07-05 1968-01-25 Voest Ag Verfahren zur Verbesserung der Trennung von Metall und Schlacke beim Abgießen schmelzflüssigen Metalles aus einem mit einem Abstichloch versehenen Ofengefäß
DE1508223B1 (de) * 1966-09-26 1970-04-09 Mannesmann Ag Schwimmerverschluss zum Zurueckhalten der Schlacke waehrend des Abstiches bei Abstichkonvertern
JPS4720803B1 (ja) * 1968-10-31 1972-06-13

Also Published As

Publication number Publication date
EP0094241A1 (en) 1983-11-16
HU187077B (en) 1985-11-28
KR840004786A (ko) 1984-10-24
DE3361476D1 (en) 1986-01-23
FI831624L (fi) 1983-11-11
CA1218846A (en) 1987-03-10
NO831649L (no) 1983-11-11
FI73739C (fi) 1987-11-09
BR8302426A (pt) 1984-01-10
AU1443583A (en) 1983-11-17
FI831624A0 (fi) 1983-05-10
JPS5952189A (ja) 1984-03-26
ES8404415A1 (es) 1984-04-16
YU102483A (en) 1986-04-30
IN159857B (ja) 1987-06-13
ES522241A0 (es) 1984-04-16
AU552735B2 (en) 1986-06-19
FI73739B (fi) 1987-07-31
ATE16945T1 (de) 1985-12-15
AR231706A1 (es) 1985-02-28

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