JPS62207809A - Slag treating method at molten iron pre-treatment - Google Patents

Abstract

PURPOSE:To prevent solidification as lumpy slag and to easily treat it, by refining continuously molten iron in a molten iron trough and slurrying the generated slag as cooling rapidly and crushing by the specified rate of an injecting flow water at the time of removing the slag from the trough. CONSTITUTION:The molten iron 4 from a blast furnace is introduced to the molten iron trough 2, and suitable quantity of refining material is injected, and then the generated slag 6 is over-flowed from a dam 10 of the molten iron trough 2 and flowed out to a branched slag trough 8. Then, this slag trough 8 is inclined by about >=1/10 toward one side direction and in case of the generated slag 6 with bad fluidity, it is mixed partially with the blast furnace flag 12. At just flowing out the slag 6 from the slag trough 8, the slag is injected under high pressure from the nozzle 14, 16 by not less than two times of the injecting flow water 18, 20 rate to the generated slag 6, to make it into slurry by cooling rapidly and crushing. The generated slurry 22 is sent to solid-liquid separator 26 through a slurry trough 24, to separate water granulated slag from water. In this way, the length of the slag trough 8 is made as short as possible and the trouble caused by clogging of the slag trough 8 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for treating hot metal pretreated slag, in particular, a method for treating hot metal pretreated slag in which, after slag discharge, the slag is rapidly cooled and pulverized using jet water to form a slurry. Regarding the method.

(Prior art) The method of continuously pre-smelting hot metal from a blast furnace in a hot metal sluice is becoming more and more widely adopted today, but the amount of slag produced during this process has also increased, making it difficult to process it efficiently. There is a need to establish a method.

Traditionally, the slag generated during hot metal pretreatment as described above is
It was common to discharge the hot metal from the hot metal gutter, then guide it into the slag gutter, where it was slowly cooled in the same way as blast furnace slag. For example, JP-A No. 60-162711, JP-A No. 60-16271
See issue 3 etc. The slag produced during hot metal pretreatment has extremely poor fluidity, so the applicant previously proposed a method of mixing a portion of blast furnace slag with the slag produced in order to improve the slag fluidity (particularly Gansho 60-274676
For example, the amount of blast furnace slag generated is approximately 300 kg.
/Ton, whereas the amount of slag generated during hot metal pretreatment is very small at less than 50 kg/Ton, and when it is discharged into the slag gutter, it quickly cools down and tends to solidify. It has been proposed to install equipment such as installing a slag pot nearby or a vacuum pump sludge remover, but this has resulted in the problem of high equipment costs.

However, in these conventionally proposed methods, it is necessary to install a large number of slag troughs around the narrow blast furnace, which may cause the slag to solidify when the temperature of the slag drops or during a pause between tapping. There is a problem that a large amount of man-hours are required to maintain the slag gutter.

(Problems to be Solved by the Invention) An object of the present invention is to provide a method of preventing slag from solidifying into lumps in a slag trough and making its handling easier.

Still another object of the present invention is to provide an effective slag treatment method that reduces the length of the slag gutter as much as possible and avoids troubles caused by clogging of the slag gutter.

(Means for Solving the Problems) As a result of various studies to realize means for achieving the above-mentioned object, the present inventors have found that the slag post-treatment, the slag treatment space, and the slag swelling due to Ca0 min. They found that the blowing method was extremely useful in solving the problem, and conducted further research to complete the present invention.

Here, the gist of the present invention is a method for treating generated slag that is continuously discharged outside the molten metal sluice when hot metal from a blast furnace is continuously refined in the molten metal sluice, A method for treating hot metal pre-treated slag, which is characterized by rapidly cooling and crushing the generated slag discharged outside the hot metal sluice with jet water of twice or more volume to form a slurry.

As described above, according to the present invention, immediately after the slag generated in the preliminary treatment of blast furnace pig iron is bathed from the hot metal trough, it is rapidly cooled with jet water of twice the volume or more of the slag to form a slurry. Therefore, a slag gutter is substantially unnecessary, and the generated slag is appropriately sent to a processing plant as a slurry with good transportability. The generated slag in this case may be a desiliconization slag, a dephosphorization slag, or a mixed slag of desiliconization and dephosphorization slag.

In addition, if the fluidity of the produced slag is poor, a portion of slag with good fluidity such as blast furnace slag may be mixed in to increase the fluidity, and then the slag may be treated with jet water.

When mixing blast furnace slag, the water slag produced by mixing 10% by weight or less is useful as a roadbed material.

In the present invention, jet water is used in an amount that is more than twice the volume of such hot metal slag, but if the amount of water is smaller than this, the risk of steam explosion will increase and it will not be possible to use a conventional slag gutter. Similarly, it is conceivable that slag may stick to the gutter equipment and not be turned into slurry.

(Operation) Next, the present invention will be specifically described in conjunction with the accompanying drawings. The attached drawings show each processing operation when the slag that is continuously discharged outside the hot metal gutter is treated according to the method of the present invention when hot metal from a blast furnace is continuously refined in the hot metal gutter. It's a sketch.

In the attached drawings, the hot metal 4 in the hot metal trough 2 shown in cross section is filled with an appropriate refining agent (for example, in the case of desiliconization, oxygen or iron oxide, etc.)
In the case of dephosphorization, lime, soda ash, etc.) are injected, and the generated slag 6 overflows into a slag trough 8 branched from the hot metal trough 2 over a dam 10 of the hot metal trough and is discharged. This slag gutter 8 is inclined laterally, and the slope is preferably 1/10 or more. If necessary, the blast furnace slag 12 may be mixed in this slag trough. Upon exiting this slag trough, a jet of water 1 is generated by high pressure water from the nozzle 14.16.
8. It is rapidly cooled at 20 to form a slurry. The slurry 22 thus produced is then sent to a suitable solid-liquid separator 26 via a slurry gutter 24, where it is separated into granulated slag (water slag) and water.

Conventionally, hot metal pre-treated slag was only used for landfill, but by making it into granulated slag as mentioned above,
It can also be used in the formulation of roadbed materials and, when mixed with blast furnace slag, as a roadbed material itself.

Furthermore, since there is virtually no length in the slag trough, there is little opportunity for the slag to solidify in the slag trough, thereby reducing the need for maintenance. Furthermore, since the slag trough is very short, the slope can be made steeper to further prevent solidification in the slag trough.

Next, the present invention will be explained by examples.

Mill scale (iron oxide) using the equipment shown in the attached drawings.
Blast furnace hot metal was continuously desiliconized by blowing. The generated slag was discharged, and separately collected blast furnace slag was mixed if necessary, and the mixture was rapidly cooled into a slurry using jet water having a volume approximately four times that of the generated slag.

Table 1 shows an example of the composition of the desiliconization slag and blast furnace slag at this time.

Table 1 (% by weight) The slurry thus obtained was sent from the slurry trough to a solid-liquid separator, and the solid content was recovered as so-called slag. Table 2 summarizes the results of evaluating the physical properties of water slag when the blending ratio (weight) with blast furnace slag was changed.

As can be seen from the results in the same table, in this example, the blending ratio of the desiliconization slag increases as the unslag CaO and metal content increase.
10 for blast furnace slag to be used as roadbed material.
It can be seen that it is best to mix at a ratio of less than % by weight.

Table 2

[Brief explanation of drawings]

The accompanying drawings are sketches illustrating the process steps of the method of the invention. 2 Hot metal gutter 4 Hot metal 6 Slag 8 Slag gutter 10 Dam 12 Blast furnace slag 14, 1
6 Nozzle 18.20 Jet water 22 Slurry 24 Slurry gutter 26° solid-liquid separator

Claims (5)

[Claims] (1) A method for treating the generated slag that is continuously discharged outside the hot metal sluice when hot metal from a blast furnace is continuously refined in the slag A method for treating hot metal pre-treated slag, which comprises rapidly cooling and crushing the produced slag using jet water at least twice the amount of slag to form a slurry. (2) the hot metal pretreatment slag is a desiliconization slag;
A method according to claim 1. (3) the hot metal pretreatment slag is a dephosphorization slag;
A method according to claim 1. (4) The method according to claim 1, wherein the hot metal pretreatment slag is a mixed slag of a desiliconization slag and a dephosphorization slag. (5) The method according to any one of claims 1 to 4, wherein blast furnace slag is mixed into the generated slag prior to quenching and pulverization using jet water.