DE102009060840A1 - System for feeding a dry cooler device for metallurgical slag, comprises a temporary storage upstream the dry cooler device, which receives impulsive effect of the metallurgical slag, and dischargeable through a tilting on a troughed belt - Google Patents

Abstract

The system for feeding a dry cooler device for metallurgical slag, comprises a temporary storage upstream the dry cooler device, which receives impulsive effect of the metallurgical slag, and dischargeable through a tilting on a thick-walled troughed belt (2). The temporary storage consists of side tiltable in opposite direction, non brick-lined, and water-cooled pan (1). The pan is emptied at the side turned away to troughed belt by the tilting in a casting bed or a collection bucket, and comprises cooling-water ducts. The system for feeding a dry cooler device for metallurgical slag, comprises a temporary storage upstream the dry cooler device, which receives impulsive effect of the metallurgical slag, and dischargeable through a tilting on a thick-walled troughed belt (2). The temporary storage consists of side tiltable in opposite direction, non brick-lined, and water-cooled pan (1). The pan is emptied at the side turned away to troughed belt by the tilting in a casting bed or a collection bucket, and comprises cooling-water ducts, which are connected to an inlet and outlet guided by a tilting axis of the pan.

Description

The invention relates to a plant for dry cooling liquid metallurgical slags, especially steelworks slag, wherein the slag is poured by means of a water-cooled, stationary pan in circumferential wells for the purpose of rapid cooling and recovery of the heat content.

Metallurgical slags are so far cooled with only relatively little effort wet. The large heat content of the liquid slag is destroyed, the environment polluted, water and energy consumed.

The large amounts of accumulating LD slag are emptied in modern steel mills from converter to slag bucket. The slag buckets are removed by rail or ground vehicle and emptied into foundries. After extensive cooling and observation, if no more liquid steel is available, is additionally cooled with water spray. Later, the slag is broken by excavators and loaded onto trucks, which brings them to the gravel plant. The steel remaining in the slag, solidified in large and small forms, is laboriously recovered from the slag.

This method has a fairly large personnel expenditure. The entire high energy content of the liquid slag is destroyed and pollutes the environment.

A significant percentage of steelworks slag must be dumped for qualitative reasons.

Austrian patent no. AT 406 378 B deals with a process for the slow, crystalline cooling of metallurgical slags which uses shallow trough baths to slowly, crystallinely cool the slag, starting from a fixed intermediate tank, in thicker layers. The method has not been proven because the intermediate container and its outlet after several batches by "increased" or "frozen" by increasing the thickness of the slag shell. The thickness of the well wall was kept low so that the capacitive cooling of the slag also remained low.

The invention is therefore an object of the invention to solve the problems described and to provide a method for dry cooling, especially of steelworks slag, which corresponds to the economic, qualitative and environmental requirements of our time with relatively low operating costs.

To solve this problem, the invention consists in that the slag emptied batchwise into an uninsulated, water-cooled, tiltable, stationary pan, cast from this regulated on uninsulated, thick-walled wells of a trough band and rapidly with a layer thickness of about 30 mm to a temperature range of about 1,000 ° C is brought. Subsequently, depending on the product, the slag is cooled to a temperature of approx. 150 ° C and loaded. Since the nature of the slag and its reuse are different, it is necessary to operate in a batchwise and flexible manner with dry cooling processes in order to achieve optimal products.

Since it does not allow the space conditions in the steelworks to situate the dry cooling directly to the LD converter, the previous removal by bucket i. a. to be kept. The buckets emptied into the stationary ladle are available again for the steelworks in a very short time. The emptying of the stationary pan takes place within approx. 10 minutes. They are adapted to the steel mill rhythm.

The performance of the troughed belt can be varied by changing the width and length of the belt. For very large amounts of slag, it may be advantageous to operate two trough belts next to each other. The stationary pan has a double drain in this case. Due to the rapid cooling of the slag to about 1,000 ° C, a very low free chalk value is achieved. This is especially important for gravel in road construction. Since the course of the refining process in the LD crucible can be very different, the properties of the slag and the proportion of liquid steel in the slag are very different, making an adapted sequence of dry cooling necessary in order to achieve an economic and qualitative optimum.

With the present method, each batch is treated separately. Their differences can be taken into account when emptying into the stationary cup as well as from the stationary cup. The transport with bucket already leads to a considerable sedimentation of the liquid steel content. As soon as when emptying the respective bucket and when emptying from the stationary pan liquid steel is observed, the emptying is stopped and the remaining largely consisting of liquid steel slag directly from the bucket or by tilting movement from the stationary pan to the rear into a collecting bucket of an existing small Gießbeetes emptied.

The small Gießbeet thus serves firstly the emptying of the residual slag with a large proportion of liquid steel. This can with the o. A. be recovered liquid according to situated sump.

Second, the slag shell formed in the cooled pan wall is dropped from each new filling into the small casting bed. Third, any incidents of failure in operation of the trough belt or slag that can not be cast require the additional small casting bed. The tilting movement of the stationary pan back into the small Gießbeet takes place, as mentioned above, in all cases as a conclusion and for complete emptying.

The cooled pan wall has the advantage that the slag shell dissolves perfectly. The constant cooling is necessary because the pan would otherwise assume even high temperatures by the non-stop refilling with LD slag of a temperature of about 1,600 ° C and the slag would stick to the pan. The cooling takes place from the outside by a closed water cooling.

At the end of the trough strip, the solidified slag is dropped by itself, pre-broken, transported up with a slow-moving cell plate belt, thrown into another spiny crusher and cooled to about 150 ° C. in the cooling shaft or a vibrating cooler.

The cooling of the slag takes place in the upper temperature range on the one hand by radiation and on the other hand by heat conduction into the thick-walled trough.

The trough is cooled in the upper strand at the bottom and in the lower strand on both sides by radiation and possibly additionally by air. For this purpose, corresponding cooling ribs are cast on the back of the trough.

A final low cooling of the wells can be supplemented by means of splash water. In order to achieve particularly favorable Los Angeles (LA) values, which are usually also dependent on the particle size, the cooling should be slow below 1000 ° C. For this reason, the slag with the trough band in a cell plate belt with very large cells (pockets) is allowed to continue to be cooled at very low speed or for a long residence time.

In order to be able to cool specifically and to have ample capacity, it is expedient to operate two trough belts together with downstream devices in parallel. The process is thus very flexible, as it requires the Stalwerksschlacke.

Since the investment and operating costs of the process are favorable and large amounts of heat are recovered, it is also very economical.

The LD slag gravel obtained by the new dry cooling process is characterized by very low free lime, uniformity and good phylical values. It is also very suitable for further processing into chippings. In the production of chippings, it may be advantageous to pour the slag in a very thin layer d. H. fill the hollows only minimally.

The process avoids explosions, frost problems, exhaust fumes and other environmental problems right from the start.

The recoverable by the described cooling steam can be fed into the existing in any steelwork saturated steam network. It represents a multiple value compared to the value of the slag itself.

The invention is described below with reference to drawings with two schematically illustrated embodiments. Show it

1 a stationary according to the invention tiltable pan on both sides, a trough band, a downstream cell plate belt with small cells and a subsequent cooling shaft and

2 a similar device with a cell plate belt with large cells (pockets).

The dry cooling plant for steelworks slag in a thicker layer consists essentially of a water-cooled, uninsulated, stationary pan 1 , which can be tilted forward and back, a trough band 2 , two spiny crushers 3 and 4 , a cell plate tape 5 and a cooling shaft 6 together.

The pan 1 has cooling channels with central supply and discharge of the cooling water 7 , The trough band will be on all sides of radiation panels 8th surrounded to absorb the radiant heat.

In the lower run of the trough band are also channels for cooling air 9 and 10 intended. The subsequent cell plate band 5 with small cells also has cooling air channels 11 ,

3 shows an example of a cross-section of a thick-walled casting mold, which form the long trough band in the required number of pieces.

The liquid slag together with residual liquid steel and impurities at approx. 1,600 ° C is emptied into a bucket by the steelworks converter. The full buckets are moved to the dry cooling system according to the invention and emptied into the stationary pan. From this pan, the slag is poured regulated on the trough band, so that the troughs z. B. continuously filled with an approximately 30 mm thick slag layer. The intensive radiation and the heat conduction into the thick-walled hollow lead to a rapid cooling to approx. 1,000 ° C with simultaneous solidification. This is followed by the discharge at the end of the belt, the precalculation and the further transport by means of a cell plate belt to the second spiny crusher and cooling shaft with simultaneous further cooling by air. The installation of radiant panels and air ducts allow the production of saturated steam of large scale, which is fed into the steam network of the hut.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• AT 406378 B [0006]

Claims (3)

Plant for feeding a dry cooling device for metallurgical slag with a dry cooling device upstream, the jerky accumulating slag receiving, emptying by tilting on a thick-walled trough strip intermediate storage, characterized in that the intermediate storage of a tiltable on opposite sides, not walled, water-cooled pan ( 1 ) consists. Plant according to claim 1, characterized in that the pan ( 1 ) on the trough band ( 2 ) turned away side by tilting into a Gießbeet or a bucket emptying. Plant according to claim 1 or 2, characterized in that the pan ( 1 ) Cooling water channels ( 7 ), which are connected to a guided through the tilt axis of the pan inlet and outlet.

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