DE6935114U - DEVICE FOR DESULFURIZING PIG IRON - Google Patents

Description

Essen, September 5, 1969 PZ 268

"Device for the desulfurization of pig iron"

Applicant: Rheinstahl Hüttenwerke AG, Essen

The invention relates to a device for desulfurizing pig iron. You have already got over 90 ί> of the sulfur used in the blast furnace through highly basic slag feed. Slag transferred. This desulfurization is more cost-effective than desulfurization in steelworks and foundries; however, it has a number of disadvantages. On the one hand, the specific coke consumption and the generation capacity increases. On the other hand, the alkali oxides introduced via the burrows and the coke are only slightly absorbed by the basic slag of the blast furnace, they accumulate in the cooking furnace and lead to increased formation and wear of the masonry, which causes disturbances in the corridor.

To avoid these disadvantages, several methods are used Desulfurization of the pig iron outside the blast furnace in Pans were developed, among other things also a mixer (GM 1 988 244), the good desulfurization results brings; these procedures are jsdocii at least insofar disadvantageous, as the desulphurisation as an additional process step disrupts the flow of materials and delays the flow of the Pfanner flow and causes additional maneuvering and crane work. Particularly The desulphurisation of the pans, which is necessary after the desulphurisation treatment, is a nuisance. A clean slag with low iron losses is still not possible today

with mechanical devices, but only possible manually. The ladle desulfurization processes are accordingly has only been used in a few special cases,

* e.g. in the smelting of siliceous iron ores,

in order to reduce the specific amount of slag to economic values, as well as in the production of low-sulfur special steels or to reduce excessive sulfur content in the event of malfunctions in the furnace.

In order to enable the pig iron to be desulphurised without impairing the blast furnace passage and without disturbing the flow of material, attempts have been made to desulphurise the pig iron in the tapping channel. The desulphurisation slag can be retained in the channel by a fox or a siphon, so that manual reticulation is not necessary. With this procedure, however, in contrast to the desulfurization in the ladle, the reaction time is predetermined by the strongly fluctuating pig iron tapping speed of the blast furnace. To weaken this influence, the desulphurisation was carried out over a longer stretch of the tapping channel (Stahl and Eisen 1969, pages 776 to 73o). For mixing the lighter desulphurizing agent with the raw material . ! iron devices such as rotating drums have been used

and channel pieces through the porous bottom of which gas was introduced (Adrianov, V.Pe _S Slkaovyj rezim domennych peeey, Moscow 1967, pp. 295-3o2 and Wo.sko Boinikoff, WG, Stal in Deutsch, 1955, volume 7). But even these processes have not been able to establish themselves operationally, since once the problem of mixing the desulfurizing agent with the pig iron could not be safely controlled; on the other hand, the well-known continuous desulphurisation

process only at low tapping speeds of 1 to 3 t / min and only with liquid desulphurising agents, such as soda, adequate desulphurization results. The outlay on equipment in the known processes is high and the operational safety, such as in the case of the known rotary drum, because of the difficulty of replacement Interferences low. The need for desulfurizing agents even for low degrees of desulfurization is high.

On the basis of this prior art, the object of the invention is to provide an operationally reliable device To develop desulphurisation of pig iron in a blast furnace tapping channel with the addition of a desulphurisation agent, the even with strongly fluctuating tapping speed of the pig iron, due to a particularly high reaction speed, a uniform and strong reduction in the sulfur content enables and which is also suitable for the whole To enforce pig iron production in a large blast furnace, and which did not adhere to the use of soda as a desulphurizing agent is bound.

According to the invention, this task is solved by a device to be switched into the tapping channel of a blast furnace, which consists of a refractory-lined container with an inlet and an outlet, the lower inner surface of which is approximately at the level of the inner bottom surface of the container, consisting of a fox with an overflow edge for the pig iron, which is connected to the spout with a sense and consists of an agitator known to it, rotatable about its vertical axis, provided with a motor for rotation about its vertical axis, which is supported as the upper part of the container and which extends from above Xn the container.

-t *

By intensively mixing the desulfurizing agent with The hot metal flowing through by means of the agitator in the container is given such a high reaction rate achieved that even with fluctuations in the pig iron throughput as a result of the often fluctuating tapping speed the desulfurization is completed to the desired level.

This result is most surprising. In the known continuously operating desulphurisation processes, such as z "3. © ei Sre'ntroiEEelTii a desulphurizing agent, soda, which forms a liquid slag is used; there is a thorough rotation of the drum _; Convergence between the desulphurizing agent and the pig iron salt; In addition, for a certain pig iron flow rate, the dwell tents of all the pig iron and slag volume units that pass through the rotary drum are the same. Despite these apparently optimal desulfurization conditions in the known rotary drums, only unsatisfactory degrees of desulfurization are achieved at high tapping speeds . It could therefore not be expected that in the device according to the invention, in which a raw iron volume is discharged from the container, for example after a single rotation of the handle, or after several times, and that there is a wide range of dwell times for the individual Pig iron and slag volume units are available, and the ßäSigen desulphurization results of the well-known turntable1 can be achieved, let alone surpassed. The width of the residence time spectrum | namely counteracts the achievement of an overall low sulfur content by the fact that the volumetric units, the | only briefly desulphurized ν. & νά & ή ^ with eggs? relafciv high ^

rim stop are fed to the treated melt, and that with the volume units, the desulphurized container is very long because of the desulphurisation rate Approach to the equilibrium values is hardly effective than with the average length of stay. As a result, provide the long desulfurized volume units do not compensate for those who are only briefly disturbed.

However, it has been shown * that with the orfindungsgenjäSen Device the good one despite the broad dwell time spectrum Desulfurization of the total melt fcis to low sulfur content from around o, oo5 # can be reached with certainty. In addition, these results are not limited to the a liquid slag-forming desulphurizing agent such as soda, but also with solid desulphurizing agents such as Lime and calcium carbide achieved. To that extent, this offers a significant technical progress, as soda as a desulphurizing agent Use with great caution because of the vapors that are produced and are harmful to health is; furthermore they are in the case of the soda desulphurisation The resulting slag, with due regard for keeping the groundwater clean, must not be carried out without extensive precautionary measures storable or otherwise usable. The reliability of the device according to the invention in achieving lower values Sulfur content and the simple, robust, failure-prone Construction make it possible to desulfurize the entire production of large blast furnaces. Essential in this Relationship is that the device as a closed unit can be lifted out of the channel using a crane and quickly exchanged for a replacement unit without further adjustment.

In detail, the device according to the invention in the following

V / eise ■ ι
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β
• be. 1 * · - 6 - gender advantageous selected valley tet

A very good throughput of pig iron and separation

Means of maintenance and thus rapid desulphurisation is achieved with an agitator in the shape of an upside-down T, the lower, bar-shaped part of which is fireproof and unra-coated. In many cooking furnace systems there is not a great difference in height between the hoe furnace tapping hole and the base edge of the transport pans that receive the pig iron. In this case, the invention recommends that the lower inner surface of the Sinlfeufs for the pig iron is approximately at the level of the inner bottom surface of the container, that the upper inner surface of the inlet is lower and that the upper inner surface of the outlet is slightly higher than the overflow edge of the Fuchses for the cast iron. An addition opening is used for the addition of the sulphurizing agent. The height of the pig iron bath in the container is kept constant by the overflow edge of the fox. The upper inner surface of the outlet or its deepest edge then holds the desulphurisation back somewhat so that it loads the container more slowly than the pig iron. This promotes the good utilization of the decontamination agent. The upper inner surface of the inlet or its lower edge is then lower than the constant hot metal bath level irr. Container, whereby the ejection of desulphurizing agents by the agitator and the running of high-carbon slag into the container are avoided.

If there is a greater difference in height between the oven tap hole and the upper edge of the Trar.sport pan, the invention applies that the inlet for · uää Hehä-iseri is in the lid of the holder and that the oven is inn # Kfiäch "d" s "is slightly higher üslsufs sls the Ub & rläüfkäftte the fox for the pig iron. At the

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This embodiment of the device is the kinetic sensor pouring of the pig iron falling freely into the bath in the container The beam is also used to mix pig iron and desulphurising agent. The desulfurizing agent will [then added to the iron jet falling into the container.

f By the fact that the bottom of the container and the bottom of the spout

are blend into each other and that the bottom dee Behäl · ters IxPA of the outlet is the direction of skating za outlet slightly inclined and that the outlet to the outside Erwei * -.

tert is «results in a simple« smooth vessel shape » which at the end of the tapping process is almost full of pig iron and slag continuously drain, so that the vessel is ready for the next sentence does not need to be cleaned * Due to the extension the run-out will also cause deposits to form

f in the outlet avoided «the effects of the addition of non-melting

S ate Entschwefelungsiaitteln such as lime and Kalziunkarbid hai? "

fig can be observed.

To prevent a short circuit between the inlet and the outlet, the lower edge of the bar-shaped stirring part is between 2 and 10 cm above the bottom of the vessel; below 2 cm the risk of bumping into any slag residues is too great; above Io cm there is a risk of a short circuit.

With high amounts of hot metal running through of around δ t / min, good desulphurization is achieved with a container, whose inside diameter is greater than 1.5 m and where the length of the bar-shaped stirrer part is ο.35 to 0.45 the inner diameter of the container is.

With this dimension of the agitator a strong and ί rapid mixing of the desulphurizing agent with the raw material |

iron and thus a high reaction speed- er! aims. At lower tapping speeds up to 2 t / rnint

the same is achieved in that the inner diameter of the container is smaller than 1.5 »and that the length of the bar-shaped stirrer part is 0.5-0.80 times the inner diameter of the container. The speed of rotation for the stirring elements is advantageously between 70 and 90 rpm. A long contact time between the pig iron and the aggregate can be achieved if the direction of the pig iron inlet points to the axis of the container and the pig iron outlet from the inlet * counting in the direction of rotation of the stirrer in the third quadrant and the addition opening for the desulphurizing agent in the fourth quadrant lies. This counteracts a direct flow by promoting the formation of circular flows in the container. Because the feed opening for the desulphurizing agent is in the fourth quadrant, it is first conveyed away from the outlet by the stirrer and mixed with the incoming hot metal stream in the area of the inlet by turbulence. To prevent pig iron from being ejected over the edge of the vessel, the upper edge of the vessel is at least 60 cm above the upper edge of the outlet. For pig iron tapping speeds of 1 t / min, container diameters of 1.2 m have proven to be good, for tapping speeds of 6 t / min container diameter of 2 m.

As is well known cer blast furnace slag can be substantially increasing the Hoehofenleis-tung by lowering the Basizitätsgrades. In addition, the blast furnace aisle is more uniform and the risk of hanging is greatly reduced. This way; Up to now, however, it has not been possible to increase the furnace output, since the high sulfur content resulting from subsequent desulphurisation _and special desulphurisation devices and in the steelworks was too expensive. It has been shown that, surprisingly, with the desulfurization device according to the invention, such high axis values are achieved.

can reduce sulfur levels from 0.070 % reliably and safely to levels below 0.010%. This also enables the use of previously unusable coke with sulfur contents above 1%; namely, in the case of a base

1 degree CaO / SiO «of the blast furnace slag of less than 1.2

■ I

even when using sulphurous coke with over 1%. Sulfur content the resulting high sulfur content on the low sulfur content of less than 0.010% can be reliably dismantled.

The blast furnace output is increased by 10 % to 15% compared to the usual, and additional cost savings are achieved through the use of low-sulfur, cheap coke.

In the following, an exemplary embodiment is given with reference to the drawing the invention explained.

They show in detail:

Fig. 1 is a sectional drawing of the device for desulfurization of pig iron with horzontal Inlet into the container,

. 2 shows a representation corresponding to FIG. 1, in which the inlet for the pig iron is located

FIg. 3 a horizontal section through the container xsaeh FIG. 1.

The device for desulphurization of pig iron in one Absclchrlnne #ipes blast furnace with the addition of a desorption

t ^ & ^{7 in} a container 2 with a

- Io -

Inlet 3 »an outlet 4 at the 3odenfläche 5 of the container 2 and a Fuchs 6 with an overflow edge 7 of the pig iron * From above rotatable about its vertical axis Rührorgön 8 extends into the container 2 in the form of an inverted T _t whose lower baikenförsiiger part 9 is refractory coated and with gear motor Io for rotation; is provided about its vertical axis and is supported on the upper part of the container 2. According to FIG. 1, the inlet opening 3 and the outlet opening k are at the same level and their lower boundary surfaces end with the inner bottom surface 5 of the container 2. The bottom of the container and the bottom of the outlet are slightly inclined in the direction of flow to make it easier to empty the vessel after the tapping has been completed. The outlet 4 is located according to FIG. 3 from the inlet 3 counted in the direction of rotation of the agitator 3 in the third quadrant and is expanded outwardly in order to prevent the slag from getting stuck above the bottom surface 5 of the container 2. This avoids a short circuit in the pig iron flowing through. The direction of the pig iron inlet 3 points to the axis of the container 2. Desulfurizing agents 1 can be added through an opening 12 at the top of the container 2. The opening 12 is located according to FIG. 3, counting from the inlet in the direction of rotation of the agitator 8, in the fourth quadrant. Both measures increase the duration of the desulfurization agent 1 in the container 2. The stirrer length is 0.5 times the inner container diameter j the upper edge of the container 2 is 70 cm above the upper edge of the outlet 4 to prevent hot metal from splashing out while stirring to avoid. The height of the pig iron in the desulfurization tank 2 is determined by the

- 11 -

- 11 -

Running edge 7 of the fox 6 connected to the outlet k by a channel, which also separates the used desulfurizing agent and the pig iron from each other, fixed. According to FIG. 2, the inlet opening 3 for the pig iron is in the lid IJ of the container 2.

gren. After finishing the blast furnace tapping, the fox becomes at or shortly before the end of parting, pierce so far below, that the solid desulfurization slag is retained or bypassed by a bypass.

With the desulphurisation device according to FIG. 1, pig iron was desulphurised during tapping of the blast furnace. The following table shows the results for high pig iron tapping speeds of h - 7 t / pig iron per minute with a vessel with an internal diameter of 2000 and for low tapping speeds of around 1 t / pig iron per minute with a smaller vessel of 1200 mm diameter. Various desulphurizing agents were used. When using lime and methane, the methane was blown into the melt through a lance outside the area of the bar-shaped agitator. ^1st '

- 12 ~

- IS -

Table: Continuous desulfurization of Stahlrohoisön

Tange des balkenför'Micen Tolles dos RUhrorgans ÖCG mm Rotational speed of the stirrer 7't rpm in

Inside
knife dos
i $ 5> iälters Medium Moh
elsen tapping
GesahwiriUif.keit
(t RB / min) iintsohwefolungoinmittel Mu nr.c
(XMV.) Chom'luoho Analyoo doü Rolioiöons before
«Ιt» r! Johnnellυηκ oil
(fS) Mn
(JS) P.
(ίί) S '
(Ji) SohwcfGlnehalt na oh
dor treatment
W) cn ""
3? C0
K>
GO 6.8 Art ν. o, 67 l, 6o o, o8o o, ol8 0.006 sacc 85 JS CnC ₂
• b 15 ^ CnCO> o, 55 1.55 o, o9l 0.089 0.005 ? ccc ⁽ i * .T «5 t» CöC _?
+ 15 fS CoCCv o, 57 . ι , ?? o, o9o o, oS2 r
ο, οοβ. ' accc CnC _? 5 »9 Kß
0.1 Nu? MS 0.5 ^ 1 1.6? o, o95 o, o52 ο, οΐ. ¹
« 1? CC c »9 CnO
> CiI _n S, ¹ »« «ε Ί, 5ο 0.6s l, 7o o, o98 o, o25 0.006 9.51 <G. 0.65 1.58 o, o8 ^ o, ol7 0.005 iiodn Ί, "9

a, * ^ -. gE! ire «ii: -ffigH3iM ^^ -" ,,.

4 «

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- 13 -

The device according to the invention can also be used for alloying and preparing pig iron or other liquid metal melts during tapping one ton per hour need the vessels only quite small to be uriö. are easily in the usual StofffIuS einsehalten.

Schtftz ^ nsoriiGhe;

Claims (1)

1.Device for desulfurizing pig iron in a tapping channel of a blast furnace with the addition of a desulfurizing agent, characterized by a refractory lined container (2) with an inlet (3) and an outlet ( ² O, the lower inner surface of which is approximately at the level of the inner floor surface ( 5) of the container (2) lies by a fox (6) connected to a channel with the outlet (4) with an overflow edge (7) for the pig iron and by an agitator (8) which is known per se and which can be rotated about its vertical axis which is provided with a motor (lo) for rotation about its vertical axis, which is supported on the upper part of the container (2) and which extends from above into the container (2). 2. Device according to claim 1, characterized in that t the stirring element (8)., The shape of an inverted T whose lower _t beam-shaped part (9) is coated fireproof. , 1 or 5 * Device according to claim ¹ 2, characterized in that the lower inner surface of the inlet (5) for the pig iron is approximately at the level of the inner bottom surface (5) of the container (2), that the upper inner surface of the inlet ( 3) deeper and that the upper inner surface of the outlet ( ² O is slightly higher than the overflow edge (7) of the fox for the pig iron and that there is an inlet opening (12) for the desulfurizing agent (1), J. or
H-. Apparatus according to claim "^ 2, characterized ge characterizing zeiehriefc _r that the upper inner surface of the spout S (4) - 15 - is slightly higher than the overflow edge (7) of the Fuchses (6) for the pig iron and that the inlet (3) for the pig iron is in the lid of the container (2). 5- Device according to one of the above claims, characterized in that the container base (5) and the 3cden of the outlet (4) merge steplessly into one another . that the bottom (5) of the container (2) and sex * 3od «ü of the outlet {4} in are slightly inclined towards the outlet (^) and that the outlet is extended outwards. 6. Device according to one of the ooigen claims, characterized in that the lower edge (ll) of the beam-conveying stirrer part (9) up to Io cm above the inner bottom surface (5) of the container (2) is located. 7. Device according to one of the above claims, characterized in that with inside diameters of the container of more than 1 _r 5 ~ the length of the bar-shaped stirrer part (9) is from 0.35 to 0.45 times the inside diameter of the container (2) . 8. Device according to one of claims 1-5, characterized in that with inner diameters of the container (2) of less than 1.5 ra the length of the bar-shaped agitator r- ^ e ils (9) the 0, ^ 5 ois c , 8o times the inner diameter of the container (2) wearing. * 9- device according to one of claims 1 to 3 »5 to 3, gelcenri is characterized by the fact that the . tvvng of the pig iron inlet (3) on the axis of the container shows and the outlet (4) starting from the inlet (3) in The direction of rotation of the stirrer is counted in the third quadrant and the addition opening for the desulfurizing agent is in the fourth quadrant. 10. Device according to one of the above claims, characterized in that the upper The edge of the container is at least 60 cm above the upper edge of the outlet (4). 63351142 «. 1.71