DE1954413A1 - Method and device for granulating blast furnace slag - Google Patents

Description

Aoieries Reunies de Burbaoh.-Eioh.-Dud © long, AHBED S. A., arenue de la Liberte, Luxembourg (Luxembourg)

Process and device to granulate by Hoohofensohlaoke.

for this registration the priorities of the Luxembourg Patent applications No. 57 207 rom October 31, 1968 and no. 58 043 rome February 19, 1969.

The invention relates to a method and a device to granulate τοη blast furnace slag, which sur Production of a granular slag with a determinable Hydraulikrermugen (pouToir hydraulique) is used.

In the oeoteohnik of road construction sioh in France the use of the coefficient alpha ( ⁰ ^) to determine the hydraulic τοη granulated Sohlaoke, which accrues in the smelting τοη Ersen and is used for the production of τοη mixtures τοη Sohlaokenkiee and Sohlaokensand Tsrwendet. By starting from the fact that the extraction of the granulated solaoke can be used as a surface treatment, one has the specifics

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Surface of the fine coal naturally contained in the granulated slag, i.e. a fine coal that quickly can be made to react, as well as the percentage the fine coal obtained after comminution under precisely defined conditions, i.e. the friability of the granules, served to the following empirical Derive context;

Coefficient oC - SxP

10 3

In this formula, S is the specific surface area, more natural fine coal (filler) according to Blaine, which is smaller than

80 / U, which has the dimension cm / g and according to the French Hormvoreohrift Nf - P 15 - 4-42 rom Mars 1967 is determined, and P is the percentage of the fine coal which is less than 80 / U, obtained by a friability test which is derived from there is a comminution under precisely defined conditions.

The coefficient «* is in excellent agreement with the mechanical compressive strength and therefore also with the hyäraulikvernögen of the granulated slag.

The granulation τοη blast furnace slag can according to different known methods such as the method of granulation in a granulation basin or a granulation port take place. In the latter process, the liquid slag is introduced into a basin in a thin stream, whose side walls with a certain number τοη Wasaer-

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Injection openings are provided. The water jets collide in an oblique direction on the thin stream of liquid slag, calling for its decomposition and the vitrification of the resulting granules. A water stream is guaranteed in the lower part of the basin the removal of the resulting slag sand. In the Granulation conditions in such plants do not allow the production of granulated slag, whose coefficient is systematically over about 40, so that the hydraulic connection obtained in this way Products are generally very mediocre.

The object of the invention is therefore to provide a method for granulating blast furnace slag and an improved gate direction for granulating blast furnace slag in the fora of a granulation basin, in which the conditions are chosen so that a granulated slag is obtained with a coefficient oc which systematically over 40 and close to 100, with the general average being between 50-70.

Previous unions had already shown that the influence of different Factors such as the pressure of the water jet or the temperature of the water used for granulation of utmost importance for the value of the coefficient oC are.

Before the invention it was already known that a temperature increase of the granulation water by 15 to 60 ⁰ C inevitably

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lent a corresponding reduction in the coefficient ⁰ ^ for the granulate obtained in this way. For this reason, an effective cooling of the Granulationswassers great importance has attached, so that the granulation is carried out with water, the temperature does not exceed about 40 ⁰ C.

Systematic tests have shown that the coefficient o <who takes a minimum value at a temperature on the order of 60-70 ⁰ C, again increases when the temperature of the Granulationswassers exceeds 70 ⁰ C. When all other parameters are kept constant, the coefficient C * of a Granulationewasser of 85 - Sohlackensandea produced 95 ⁰ C as high as in the granulation with water whose temperature is lower than 40 ⁰ C. Based on this finding was the cooling circuit is switched off and the granulation vermittele a circulating Granulationswassers made, whose temperature ranged between 85 and 95 ⁰ C. If it is true that the values of the solk sand obtained in this way are not significantly higher than the values for the coefficient <X, which has ^{been granulated with water at a temperature below 40 °} C. or at 40 ^° C., this already means an important one Step towards a much more economical granulation process. Since it was indeed possible to work with a closed circuit, all piping systems and containers used to cool the granulation water are covered.

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become liquid. This result enables a collection of ~ borrowed cost savings in terms of construction, operation and the maintenance and care of such a system.

In addition, in contrast to previous practice, a move was made to increase the pressure of the granulation water beyond 4 kg / om to an optimum value of almost 10 kg / om. The pressure can even be increased up to 15 kg / om, the upper limit being determined by economic considerations. In this way the values of the coefficient οί could be increased in an amazing way. For example, the mean value of the coefficient d at a pressure of granulation water of the order of 8 kg / om without further reaches the value 65, in contrast to a value of less than 40 when the pressure of the granulation water is below 4 kg / om, regardless of one relatively low temperature of the slag.

According to the method according to the invention, the water used for granulation is used under a pressure of more than 4 kg / om injected, with the preferred «Druok about 10 kg / oa. Dl · to carry out the invention Procedure used device consists of a * Granulation basin, the inventive »ate characterized by this let »that dl« number of waea injection openings, • owl · the general cross-sonality of all openings for «in · wished AueetrtauMng in a given page depending on

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speed γόη the chosen one, but above 4 kg / cm Pressure are set.

You shape the granulation basin and especially the look! the same in the walls sur water delivery gate viewed openings, as well as the total area of the openings fall within each depending τοη the pressure fixed, the τοη for a particular Durchsats Granulationewasser is to be maintained "The Geeamtwasser- 'durchsats is in turn for its part, by the Amount of slag determines which is to be granulated per unit of time.

Another feature of the GranulatiossbeckeBS is that that the basin is divided into two branches, which are separated fed with water. The two irrigation devices can be connected to each other by a hinge connection of any design, which serves the purpose within in the pool to compensate for any tensions that may arise. The water injection ports are in several rows the inner walls of the two irrigation gates of the Granulatlon system arranged.

If the granulation is done with he! Bern water, you could expect that the water vapor formed in large quantities the sole grains enveloped and a · plStsliohe Hardening prevents hardening, which leads to stronger crystallization would be favored than the glazing. Laboratory test in the received Sohlaekexuiazid a * b «a but tends to, that

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This is not the case. Basically, this can be traced back to the planning of the plant and the appropriate choice of granulation conditions. Ba Waseer Ton 85 I) Ib 95 ⁰ O evaporates practically instantly, the cooling capacity of this water is at least as high as that of a water of 40 ⁰ O ₁ which cools to the large Xe11 through contact. The cooling, which takes place exclusively by evaporation, is effectively achieved by the very high bridge which favors intimate contact between the slag and the water and which seems to prevent the above-mentioned insulating shell from being formed. Despite the use of hot water, there is therefore a sufficiently sudden cooling of the surface, which is completed by the swirling of the water and finally in the emptying channel. In addition, under these conditions the grains are even finer, so that the heat exchange can take place even more easily despite the poor thermal conductivity of the slag. The fact that crystallization occurs at the end of cooling is therefore reduced to a minimum. The obtained Sohlaokensand is homogeneous in terms of grain determination and vitrification, and the grain spindle indicates finer grain sizes, whereby the value of the coefficient ex is advantageously improved.

It is to be noted that instead of the granulation of blast furnace slag with water, the temperature is about 90 ⁰ O and which is injected into the Granulationsbecken with a bridge of more than 4 kg / cm, a less hot

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or even cold water can be used to make the to achieve the same advantageous results, provided that the injection pressure is selected accordingly. It is with that managed to prove that to produce a high quality slag sand in contrast to the current Also practice both granulation water under a higher one can be used as the commonly used pressure can, so that the granulation of the blast furnace slag becomes independent of expensive cooling devices in this way.

With the aim of reducing the number of water circuits and making water consumption more economical, according to a further development of the method according to the invention, the circuit of the granulation water8 can be combined with the cooling water circuit of the blast furnace. In order can which is made in the immediate vicinity of the blast furnace in! Clock of taps granulation by means of the blast furnace cooling water made its temperature is between 40 ° and 50 ⁰ C. This water is pumped directly from collecting channels into the granulation basin. If the sedimentation basin has a filter floor, there is also an additional and free treatment option for the blast furnace cooling water. At the exit of the settling basin for the granulated slag, the cleaned hot water is collected, reintroduced into the primary feeder and fed to the cooling device of the blast furnace.

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Further features of the invention are evident from the following Description of various examples in connection with the drawings, in which χ

fig. 1 a schematic representation of a granulation token,

fig. 2 a vertical section through the basin of FIG. 1, and

Pig. 3 is a relevant illustration of a "wide embodiment of a granulation basin" which allows the method according to the invention to be carried out.

According to the invention is 1.2 ohwanken the liquid slag, whose basicity swisohen under the given conditions by the applicant production to 1.5 "and poured into tin Gtranulatlonsbeoken 1 whose temperature" wipe may be 1350 to 1550 ⁰ O, * the "white Btwäeserungsvorrlohtungen 2, which are connected to one another by an articulated connection 3. The granulation beken used for this is similar to the basin shown in Figures 1 and 2. Each watering device of the Beokens has about 14 whiskey orifices 4, the total area of which, that is to say the cross-section of the water, is about 0.42 dm. A circulation pump ensures an injection pressure of the order of 8 kg / omega. The jets of water, the temperature of which is "wischen öü> and Sb ⁰ O", are directed in an oblique direction towards untou and "ur Vordarauite de" Beokens. at

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the contact with the water jets becomes the one on the Water curtain 8 impinging - thin stream of liquid slag 7 in a large number of grains, which are carried away by the eddies of the water. After the grains bounced back several times on the walls and floor and experienced a sudden cooling, they will γόη the sum Abs et »basin-going Waseeretrom. The cooling and the complete glazing take place in the ■ water used for removal. The sedimentation basin is designed like this! that there is a rapid draining of the SoblackensanScr permitted, whereby the latent lurttok held in the grains " Wäxw ensure the evaporation of a large rope of the undrained, urüokblelbenden water.

The one required to make a ton of sludge sand Amount of ron örenulationa water is 5 to 10 m / t, with only a little water to supplement the evaporated water is required *

This becomes a general nitration in the Absetsbeoken is called water without further cooling treatment just like in the previous proceedings, overturned again. As mentioned above, the use of cooling water is available not in the way, except for the daduron-related sueätsliohen Costs that result from setting up and operating a cooling system.

The mean value for the coefficient oi of the soleplate sand produced by means of the method described is

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at 65, i.e. the specific surface area and thus also that Hydraulic capacities have very favorable values and are far better than those with relatively cold slag since then achieved values.

In which. described method, in which · »the thin · jet of liquid slag in an essentially vertical direction falls on the curtain of water that falls through the water rungsvorriohtungen emerging water jets is formed, it is not uncommon that liquid · slag from the The water curtain bounces back and is thrown out of the pool. The ejection of slag is even more favored, if the height between the feed trough for the liquid slag and the settling basin is reduced and / or the injection pressure of the water is increased. For protection The granulation system described can be provided with a protective enclosure 5 to prevent slag from being ejected from the surroundings which is closed on the top by a plate covering the enclosure.

In view of this inconvenience, the procedure and the granulation pool of the type described above world developed. You further embodiment can be found in Use advantageously in all cases in which, as a result of the lack of sufficient space, of the desire, the dimensions to reduce the system, or as a result of the given in an existing system planned for renovation Conditions it is impossible to have a sufficiently large

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Provide way for the free fall of the liquid slag.

In Pig. 3 is the Auführungeform shown Slag is no longer poured in a vertical direction onto the curtain formed by the water jets »but the water jets wipe in an oblique direction. In this way all "wipe the jets of water introduced with the liquid slag coming to the bottom." Jets of water lurüok could bounce off, caught and by the upper rays carried away · lifting the lower height has This arrangement also includes the door part that no special protective bezel is required"

The liquid slag runs from an inclined chute 11, which consists of carbon blocks. Compared to Hinnen, which are usually made of sealing material consist, ensure grooves made of carbon blocks or "Carbon bricks" have a lifespan that is more than ten times longer. . The jet of liquid slag falls in at the mouth of the channel oblique direction, the jets of water coming from the two irrigation devices 2 of the granulation bezel will be given off, and therefore will be on all sides of water surrounded, so it is practically impossible to eject the slag.

The granulation beken itself consists of two irrigation devices 2 that are independent at the edges the lower gutter are attached, welohe on their rear surface a bineprita opening 12 for the «um

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Has removal of the slag serving water. After an often unavoidable solidification of the slag on the lower hand of the feed chute, it happens that a rope of the liquid slag falls down from the chute in a vertical direction and is not caught by the water jets. In order to prevent the formation of larger agglomerates in the feed chute, the lower cable of the granulation jaw has an extension 10 which is guided forward to a point below the feed chute for the slag. The walls are old with several rows of round holes 4-6 mm in diameter, the jets of water emerging from these holes are directed in an oblique direction near the front and near the bottom. The two irrigation devices are heated separately from each other with the cooling water of the blast furnace under a pressure of more than 4 kg / cm and with a temperature as low as 40 to 50 ⁰ O. The granulated slag is fed to the settling basin together with the water used to remove the granulate " which has a plate bottom. After the filtration, the granulation water is fed back into the water cycle of the Hoohofen and first introduced into the cooling device * before it is used to cool the furnace «

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Claims (8)

Patent claims: 1. Method sum granulation of blast furnace slag in a granulation basin, with the formation of a granulated slag τοη increased hydraulic capacity and increased coefficient o ( , thereby gekennaelehnet that the sur granulation serving water under a pressure of more than 4 kg / cm is injected with the preferred Pressure is about 10 kg / cm. 2 · A method according to claim 1, characterized in that as Granulationnwaiaer umgewälstes and not chilled water is used, the temperature is higher than 70 ⁰ C and preferably wipe!. 85 ° to 95 ⁰ O amounts. 3. The method according to claim 1, characterized gekennae lehnet, since £ as Granulationswaaeer the ^{cooling water of a blast furnace, which is at a temperature between 40 ° and 50 0} O, is used and this water is returned to the water cycle of the blast furnace after treatment in a Absetsbeoken with iilterboden. 4. Device for granulating Hoohofensohlaoke » in particular granulation tokens, for the execution of the method according to one of claims 1-4 »characterized in that the number of water injection openings (4) · as well as the total cross-section of all openings for one 009886/1268. - 15 - ORJGiNAL Desired outflow rate in a given 2Side In Depending on the selected, but above 4 kg / cm Pressure are set. 5. Apparatus according to claim 4 »characterized in that that the GranulatIonsbeeken (1) divided into awei branches 1st, which are fed separately with water and connected to each other by a known articulation are, which serves inside the pelvis evolving tensions auesugleiohtn * b. Device according to claims 4 and 5 " characterized in that the mutual position of the two irrigation devices"! (2) and the feed channel (11) for the liquid slag are selected in such a way that a thin jet of liquid slag (7) enters between the water jets (8} which are pressed in under a pressure of more than 4 kg / om 7. Device naoh claims 4-6, characterized in that that the two irrigation devices (2) are provided on their underside with an extension (10) that extends up to one below the feed channel (11) for liquid slag lying point is led backwards. 8. Apparatus according to claim 4, characterized in that the feed channel (11) for liquid slag from refractory Carbon blocks η consists. 009888/1268