Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B3/00—Charging the melting furnaces
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B5/00—Making pig-iron in the blast furnace
  • C21B5/001—Injecting additional fuel or reducing agents
  • C21B5/003—Injection of pulverulent coal
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B5/00—Making pig-iron in the blast furnace
  • C21B5/02—Making special pig-iron, e.g. by applying additives, e.g. oxides of other metals
  • C21B5/023—Injection of the additives into the melting part
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/20—Recycling

Definitions

• the invention concerns a process for returning scrap into a cupola furnace for preparing silicate melt for the production of rock wool, and a device for returning scrap into a cupola furnace for preparing silicate melt for the production of rock wool.
• the invention relates to returning the scrap produced during the production of rock wool back into the process.
• Silicate melt which is produced in cupola furnaces out of lump raw materials of the usual grain size of 30 to 200 mm, is most often used for the production of rock wool.
• the scrap produced in this process after the defibration of silicate melt amounts to 30 % of the weight of silicate melt, depending on the defibration procedure.
• Scrap is also produced during further processing of mineral rock, i.e. throughout the production line. Scrap usually appears in fibrous or pearly form, and represents an ecological and economic burden.
• Silicate melt is produced in cupola furnaces.
• a cupola furnace for the production of silicate melt is a special version of shaft furnace consisting of an upright, mainly double-walled, water-cooled iron tube, which is closed at the bottom by a removable lid lined with refractory mixture.
• the charging with raw material and heat producing fuel is performed from the top by means of a dosing device.
• Coke is normally the fuel which produces the necessary heat for melting.
• the oxygen or air needed for coke combustion is brought in at the lower portion of the cupola via a row of tuyeres. Heat is released during coke combustion in the cupola, which is reflected in reactive temperatures above 1500 °C, the result being the melting of raw material.
• the melt Due to gravity, the melt accumulates in the lower portion of the furnace and flows away through a side opening into a defibration machine. Flue gases which are produced during coke combustion flow away through the intermediate space between pieces of coke and raw material towards the upper portion of the furnace, where a stack or a fume exhausting pipeline is installed. In this way, flue gases preheat the pieces of raw material lying above the melt.
• the usual raw materials for the production of silicate melt are: diabase, basalt, amphibolite and other convenient alumino-silicate magmatic minerals, or various types of metallurgical slags.
• the most usual process is the briquetting process, where scrap is ground to obtain the desired granulation and compressed with the addition of cement into briquets which, when the cement hardens, give scrap the necessary lumpy form, size and hardness.
• scrap and raw materials are processed separately, and only when melted they are processed together in a special melting unit.
• the invention seeks to find a solution to the problem of returning scrap easily into the furnace without its preliminary processing, and without interrupting the flow of flue gases or causing undesired emissions into the environment.
• this problem is solved by a process for returning scrap into a cupola furnace according to which scrap is fed against the wall of the lower portion of the furnace at the same time as the furnace is being charged with raw material and fuel, by means of a device consisting of a revolving portion with a scrap feeder installed between the lower and the upper portion of the furnace.
• An oxygen adding device belongs to the standard furnace equipment, and it is basically intended for regulating the temperature of the melt, the capacity of the cupola, starting the furnace, and the like.
• the feeding of scrap against the inner wall of the furnace results in a reduced direct contact of fuel with the wall.
• the wall which is usually water-cooled, heats less.
• Figure 1 is a schematic elevation view illustrating a cupola furnace
• Figure 2 is a schematic cross-sectional view illustrating the charging of the furnace
• Figure 3 is a cross-sectional detail illustrating a cupola furnace and a scrap feeder with drive
• Figure 4 is a detail of the first embodiment illustrating the control of the revolving portion of a furnace
• Figure 5 is a detail of the second embodiment illustrating the control of a revolving portion of the furnace.
• FIG. 6 is a cross-sectional/plan view illustrating the revolving part with a feeder and control.
• the cupola furnace has a lower portion 1 with a (usually) water-cooled wall 8, where air is blown through tuyeres 6, the air being enriched with oxygen when needed for the combustion of fuel, this usually being coke.
• Said lower portion 1 has an outlet 7 for the melt.
• the process of fuel combustion and raw material melting takes place in the area of tuyeres 6, while above it, the pre-heating of raw material with flue gases is taking place.
• the under the invention is located between said lower portion 1 and an upper portion 2.
• Said upper portion serves for charging the furnace with raw material and fuel via a conveyor 5, and for removing flue gases through a stack 3.
• Figure 1 illustrates how the lower portion 1 and the upper portion 2 are fixed by supporting frames 22, which, in the pictures, are shown only schematically to allow better clearness.
• the device in accordance with the present invention and with the embodiment consists of a revolving portion 4 with feeder 10 and supporting structures 13, and a guiding ring 11 and a driving ring 12 on the periphery of the upper edge of the lower furnace portion 1
• the arrangement of said supporting structures 13 along the circumference of the revolving portion 4 is shown differently in Figure 1 than it is shown correctly in Figure 4, all for the sake of better clearness.
• the revolving portion 4 is installed, in as much as possible gas-proof way, between the lower portion 1 and the upper portion 2.
• a scrap 24 feeder 10 consisting of worm conveyors with a drive 17 is fixed to the revolving portion 4.
• the upper portion of the feeder 10 is a scrap 24 collector tank 18 At the side of the feeder 10 there is a drive 14 with a toothed wheel 21.
• a guiding device 15 is arranged on the revolving portion 4 above the feeder 10, which directs the scrap 24 which is pushed by a worm conveyor against the inner wall of the lower portion 1 of the furnace
• the guiding device 15 is carried out as a screen lying in acute angle to the wall of the revolving portion 4 over the outlet of the feeder 10.
• the supporting structures 13 enable the rotating of the revolving portion 4 alongside the guiding ring 11 mounted at the upper circumference of the lower portion 1 of the furnace.
• the horizontal wheels 19 guide the revolving portion 4 in horizontal direction
• the vertical wheels 20 and 24 carry the revolving portion 4, guiding it in vertical direction, namely all the wheels: 19, 20 and 24, alongside the guiding ring 11 which is mounted at the upper circumference of the lower portion 1 of the furnace.
• the guiding ring 11 is structurally linked with a driving ring 12, which is toothed along its periphery in order to match the toothed wheel 13 of the drive 14 on the feeder 10.
• a guiding ring 23 is added at the lower circumference of the upper portion 2 of the furnace for vertical guiding, and the supporting structure 13 is shaped in such a way as to allow the vertical wheel 25 to sit onto the ring 23.
• Another possible embodiment is with the driving wheel on the periphery of the revolving portion 4 and with the drive 14 on the lower portion 1 or the upper portion 2.
• the charging of the furnace proceeds as follows: in idle state, the tank 18 of the feeder 10 is filled with scrap 24 via charging unit 9.
• the charging of the furnace begins when the level sensor senses that the furnace needs re-charging.
• a drive 17 starts pushing the scrap 24 over a worm conveyor into the furnace, while simultaneously the drive 14 starts rotating the revolving portion 4 over the toothed wheel 13 in engagement with the driving ring 12.
• the guiding device 15 directs the scrap 24 close to the inner wall 8 of the lower portion 1.
• the feeder 10 rotates by two cycles.
• the charging of furnace with raw material and fuel or a mixture 26 of raw material and fuel may proceed in the known way, and there is no need to modify the furnace in accordance with the invention.
• the invention is not limited by the stated sequence of charging the furnace, and it is possible, in accordance with the invention, to use any consecutive or simultaneous charging of the furnace with the scrap 27 and the mixture 26, however, always with the scrap 27 being charged against the inner portion of the wall 8 of the lower portion 1 of the furnace.
• Figure 2 shows, in a schematical cross-sectional view of the furnace, consecutive charges with the scrap 27, raw material and fuel, or a mixture 26 of raw material and fuel.
• the thickness of the scrap 27 layer against the wall 8 is between 8 and 0 cm, and approximately 25cm.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Metallurgy (AREA)
• Vertical, Hearth, Or Arc Furnaces (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Furnace Charging Or Discharging (AREA)
• Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Processing Of Solid Wastes (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20431879

Family Applications (1)

Country Status (6)

Citations (9)

• 1996
  • 1996-07-24 SI SI9600236A patent/SI9600236B/sl not_active IP Right Cessation
• 1997
  • 1997-06-17 HR HRP-9600236 patent/HRP970335B1/xx not_active IP Right Cessation
  • 1997-07-18 CZ CZ99180A patent/CZ18099A3/cs unknown
  • 1997-07-18 SK SK92-99A patent/SK9299A3/sk unknown
  • 1997-07-18 WO PCT/SI1997/000023 patent/WO1998003438A1/en not_active Application Discontinuation
  • 1997-07-18 EP EP19970930974 patent/EP0914296A1/en not_active Ceased

Patent Citations (9)

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