DE10027432C2 - Process for the removal of solid desulfurization slag which forms during the desulfurization of pig iron - Google Patents

Abstract

The invention relates to a method and device for conveying away slags, especially desulfurization slags, which form on pig iron melts or steel melts. According to the invention, the slag layer drawn off from the surface of a pig iron melt or steel melt is poured into a vessel and, after pouring, the slag is cooled down by means of a cooling medium. Once a predetermined temperature is fallen below of, the vessel is subsequently tilted for emptying. According to the invention, the pouring takes place in rhythm with the deslagging, whereby the respective quantity of deslagging is assigned to only one vessel that is moved in rhythm past the deslagging point, and the quantity of slag poured inside is continuously cooled down along a fixed distance and is subsequently dumped.

Description

The invention relates to a method for the removal of pig iron during desulfurization solid desulfurization slag that forms according to the generic term of claim 1.

The slag that forms on the surface of the pig iron during desulphurization is drawn off into large slag pails or slag boxes by means of a slag scraper. After slagging, the slag buckets are cooled for several days and then soaked for at least 2-3 days. The slag is cooled down by means of the cooling medium water so that emissions or deflagrations do not occur when it is dumped. The temperature of the cooled slag should be less than 400 ° C to avoid odors caused by the formation of H ₂ S gas. Disadvantages of the known method are the long waiting time until the slag cools down and the provision of a large number of slag buckets in circulation, including the transport logistics required for this.

From DE-PS 618 451 a system for the casting of hot melt materials, especially known from blast furnace slag. In this known method the molten material flows out of a channel into a multi-chamber feeder. This dispenser, usually provided with four chambers, can rotate or back and forth oscillate. The chambers of the distributor are preferably cooled from below, they can also be heated, for example, to make the blast furnace slag more fluid close. As soon as the chamber facing the channel is filled, it turns or swivels the allocator so that the contents of the chamber are funneled into a container pours.

A plurality of such containers are arranged on a continuous endless belt, which in the Cycle of emptying the feeder past the funnel. Depending on what is poured, the containers pass through a water bath for rapid cooling or a gas flow to slowly cool the goods. When returning the empty one Containers through the water bath are pulled up and run through to dry a heated tube. This drying is necessary so that when filling the melted good does not come to a deflagration.

The object of the invention is to provide a method for the removal of sulfur during desulfurization of pig iron forming solid desulfurization slag and a device to indicate that the not described disadvantages.

This task is based on the generic term in conjunction with the characteristic Features of claim 1 solved. Advantageous further training are the subject of subclaims.

The problem is solved with regard to the device by claim 4. Advantageous further developments of the device are the subject of subclaims.  

According to the teaching of the invention, the amount of slag drawn off is divided into subsets subdivided, with the partial slag amount deducted only one in time is assigned to containers moving past the deslagging point. Subsequently is the amount of slag filled in along a specified path cooled continuously and then discarded.

The proposed method has the advantage that the removal of the withdrawn Slag is clocked in partial quantities and this partial quantity takes place in a much shorter time can be cooled.

To carry out the method, a so-called trough conveyor is proposed from a large number of similarly designed containers or troughs, all around are arranged. The containers that can be attached to one another can form an endless train, the containers being provided with wheels that run on a closed Unroll the rail band. In another embodiment, the containers are open arranged in a separate circulating endless belt. To in case of damage To be able to replace damaged containers, they are detachable on the endless belt attached. With each stroke of the slag scraping, the endless belt or Container train back a specified conveying path. After filling it goes through Endless belt or the container train a cooling section and promotes after dropping the cooled slag the empty containers back to the filling area. This eliminates the complex transport logistics for many slag buckets in circulation.

One problem is the risk of the slag adhering Pig iron or steel on the wall of the collecting funnel or the individual Container. In the case of the collecting funnel, the problem described is thereby avoided making the inclined surfaces of the funnel so steep that the Contact time is not sufficient to allow attachment. The disadvantage here is that the funnel becomes very long in order to have the required opening width. alternative To do this, it is proposed that the inner surfaces of the funnel be cooled with copper plates undress. This variant can also be used for the individual containers that are in Modification to this can also be designed as water-cooled copper troughs. Another method offers itself in such a way that before filling the  hot slag, fill the container with a cold solid part beforehand. Preferably this solid ground slag.

When the containers are arranged on the endless belt, they form on top of each other subsequent containers gaps. So that no hot ones in these spaces Slag can fall into it, each container has a space covering this space Cover plate on.

Further features, advantages and details of the invention result from the following description of an embodiment shown in a drawing example. Show it:

Fig. 1 as a schematic diagram of a trough conveyor designed according to the invention

Fig. 1 shows a basic diagram of an inventively embodied trough conveyor 1. It consists of a revolving endless belt 2 , which is only symbolically indicated here, to which several containers 3 of the same design are attached. The direction of rotation 4 of the end losbandes 2 is marked with an arrow. The procedure carried out with this trough conveyor 1 for the removal of removed slags proceeds as described below. From a pan, not shown here, a certain amount of slag 5 is drawn off by means of a scraper scraper, also not shown here, ie in time with the stroke of the scraper scraper. This falls into a collecting funnel 6 , which is arranged above the endless belt 2 and from there directed into a container 3 below. In this exemplary embodiment, a filling station is connected upstream of this filling station. This has a feed hopper 7 , through which the previously empty container 3 is given a predetermined amount of granular solid 8 . Preferably, the granular solid 8 is cold slag ground. As a result, the respective container 3 is partially filled. This pre-filling prevents the remaining portion of pig iron or steel in the slag 5 from adhering to the wall of the container 3 . During further transport, the containers 3 pass through a cooling section, here in the form of a cooling tunnel 9 . As seen in the transport direction 4 of the endless belt 2 , a plurality of nozzles 10 are arranged in the cooling tunnel 9 , from which a cooling medium 12 , preferably water, sprays, the jet being directed onto the filled containers 3 passing by. The arrangement of a cooling tunnel 9 has the advantage that the vapors which are unavoidable during spraying can be sucked off in a controlled manner.

For this purpose, a suction device 13 , which is only indicated here, is installed on the cooling tunnel 9 . Since each container 3 has only a relatively small amount of slag 5 , it is ensured that the cooling section is sufficient to cool down the amount of slag 5 introduced in coordination with the average transport speed of the endless belt 2 . At the reversal point of the endless belt 2 , the containers 3 come into the tilted position, so that the total content, ie the pre-fill quantity + slag quantity 5 , can be dumped out. A trough 11 arranged at this point forms the collecting point. From there, the slag that has already cooled can be removed and used for further use. A part of it can be ground and returned to the feed device 7 as a pre-filler. So that no hot slag 5 can fall into the spaces between the successive containers 3 , each container 3 has a cover plate 14 .

LIST OF REFERENCE NUMBERS

1

trough conveyor

2

endless belt

3

container

4

transport direction

5

amount of slag

6

receiving hopper

7

feed hopper

8th

Vorfüllmittel

9

cooling tunnel

10

jet

11

trough

12

cooling medium

13

suction

14

Cover plate

Claims (10)

1. A process for the removal of solid desulfurization slag which forms during the desulphurization of pig iron, in which the hot slag layer drawn off from the surface of a pig iron melt is poured into a container and, after filling, the slag is continuously cooled by feeding in a cooling medium along a specified path and falling below at a predetermined temperature, the container is finally tilted for emptying, characterized in that the filling takes place in time with the deslagging, the respective amount of deslagging being assigned only to a container moving past the deslagging point in time. 2. The method according to claim 1, characterized, that before filling the removed hot slag with a cold granular solid part to be filled and after cooling the total content of the respective container is dropped. 3. The method according to claim 2, characterized, that a ground, cold slag is used as a solid. 4. Apparatus for carrying out the method according to claim 1 with a ladle containing the pig iron melt and a continuous slag receiving the slag, which is provided with a plurality of containers of the same design, characterized in that the solid slag floating on the pig iron melt by means of a cyclically moving Slag scraper removed and with each stroke of the slag scraper, the endless belt ( 2 ) travels a fixed conveying path and a collecting funnel ( 6 ) is arranged in the inlet area of the hot slag ( 5 ) that has been removed. 5. The device according to claim 4, characterized in that the inclined surfaces of the collecting funnel ( 6 ) have a small angle with respect to the vertical. 6. The device according to claim 4, characterized in that the collecting funnel ( 6 ) is provided on the inside with cooled plates. 7. Device according to claims 4-6, characterized in that the filling area upstream of the empty container ( 3 ) a cold granular solid feed hopper ( 7 ). 8. The device according to claim 4, characterized in that each container ( 3 ) is provided on the inside with cooled plates. 9. The device according to claim 8, characterized, that the plates are designed as water-cooled copper plates. 10. The device according to claim 4, characterized in that each container ( 3 ) is designed as a water-cooled copper trough.