Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B5/00—Making pig-iron in the blast furnace
  • C21B5/008—Composition or distribution of the charge

Definitions

• Blast furnaces for the reduction of E isenerzen in the form of lump ore, sinter, pellets or the like are fed usual such that the ore is with and without additional batch abandoned separated from the coke.
• the procedure is such that the batch of gout bells closes more or less strongly against a cylinder with adjustable diameter as an impact armor and is more or less pushed back from there or practically falls vertically downwards.
• the material hits the fill in a ring, rolls to the center and to the edge and forms an embankment to the center and to the edge with a slope of normal 30 - 35 0 .
• This is the usual practice, since in the ring zone a stronger decrease in the bed than is done in the middle, and thereby the stratification after a certain drop in p RAK table is horizontal.
• the embankment on the one hand to the center and on the other hand to the edge of the shaft causes the coarse material to roll preferentially to the center and to the edge in both the ore and coke batches and promote the flow there. This corresponds to the prevailing practice that one is somewhat stronger on the edge and in the middle, but otherwise completely even gas flow provides the best operating results. A completely even distribution of coke and ore is also sought over the entire cross-section of the shaft.
• a rotating chute is preferred as the feed device, the angle of inclination of which can be changed depending on the feed of coke or ore, so that the material can hit the bed in a narrower or wider ring, e.g. is described in German patent specification 2320 532.
• German patent specification 2320 532 e.g. is described in German patent specification 2320 532.
• nothing fundamental has been changed in the way coke and ore are distributed across the shaft cross-section.
• the mold gases formed from CO + H 2 in addition to N 2 in the blow mold cavities are distributed from the blow mold cavities over the entire shaft cross-section, with the flow being considerably increased towards the center and partly also at the edge and between the blow mold cavities, since there layers predominantly or exclusively from lumpy coke, which participates only to a very small extent in the reactions, while above the blow mold cavities alternately coke and partially reduced ore layers occur, which offer greater flow resistance.
• coke and ore layers sinking rapidly downward meet specifically smaller amounts of mold and shaft gases.
• significantly smaller amounts of heat and CO + H 2 are available for the reduction in the ring zone than in the central and peripheral zone.
• the reduction above the blow mold cavities cannot be completed and the iron ore enters the blow mold cavities only partially reduced and unmelted. This leads to the reduction and melting of iron and slag in the blow mold level, which results in higher C consumption and air consumption.
• German patent specification 1 758 372 claims a method of adding fuel in the middle and a ring zone on the wall and Möller in the ring zone in between. For this purpose, ring-shaped partitions and a discharge of top gases from two zones are recommended in the upper part.
• German patent specification 1 252 214 claims a method of heating coke with a grain size of 5-50 mm in an amount of about 400 kg / t of pig iron in the peripheral zone and next to it in the middle zone Möller and reduction and coaling coke with a grain size of 50-80 mm give up in an amount of about 200 kg / t RE.
• the aim of the invention is to largely compensate for the differences between the individual zones.
• a certain compensation is achieved by the known injection of fuel through the blow molds, whereby coke is saved and the sinking of the bed in the ring zone is slowed down.
• measures are carried out to increase the flow resistance in the middle and edge zone and to reduce it in the ring zone.
• above average ore and therefore below average coke should be added to the middle and peripheral zone in order to better utilize the heat and CO of the shaft gases rising there.
• coke for the conversion of C0 2 to 2 C0 and for carburizing the iron in an amount of 100 to 200 kg C / t of the pig iron produced there can be used.
• ore is to be supplied in an increased quantity to the central zone and similarly to the peripheral zone, it also being possible here to use the finer ore with greater flow resistance.
• the coke should also preferably be smaller than it is fed to the ring zone.
• the coke available to the blast furnace is expediently separated into two grain classes, namely with a grain size of, for example, above 50 and below 50 mm.
• the bell With the usual bell lock, a center drop can be achieved in that the bell additionally has a central outlet with its own bell lock or better with lower flap lock with connected central downpipe.
• the bell is then operated as usual to charge ore and coke.
• the desired quantity of ore is fed through the central zone in the middle zone.
• Additional quantities of ore in the middle and in the edge zone are expediently introduced to the extent that an advance in the temperatures in the middle and edge zones is observed in relation to the ring zone and how the coke consumption is optimally reduced.
• the central and peripheral zone of coke is expediently fed in in an amount of only 100-200 kg t of pig iron and preferably in small pieces, while the ring zone is supplied with as much coke and preferably in a coarse manner as the blast furnace as a whole requires.
• a flap lock with a central downpipe and a rotating chute is available instead of a bell lock with impact armor
• the angle of inclination of the coarse or fine material of coke or ore can be changed depending on the task, e.g. described in German patent specification 2320 532 so that the impact point for the material in the middle, ring and edge zone can be set as desired, so the measures according to the invention can be implemented with simple means.
• a rotating chute it is also possible to reinforce the ore and fine-grained edge zone Add coke between two blow molds. Between the blow molds the lowering of the fill is less than directly above the blow molds, so that it can be blown through more easily here. This can be prevented if the rotary chute is stopped in the middle between two blow molds for a certain time when adding ore or fine-grained coke to the edge zone. This measure can be carried out in regular periods or also when required, i.e. in the case of observed marginal disorders.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacture Of Iron (AREA)

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• 1978
  • 1978-03-23 DE DE19782812788 patent/DE2812788A1/de active Pending
• 1979
  • 1979-03-21 EP EP79100849A patent/EP0004373A3/fr not_active Withdrawn

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