JPH01176040A - Method for recovering metal from molten iron desulfurized slag - Google Patents

Abstract

PURPOSE:To recover high-quality iron from desulfurized slag at a low cost by charging the desulfurized slag into an empty molten iron pan after desulfurization, further receiving molten iron in the pan, and again discharging the desulfurized slag floated by the agitation at the time of receiving molten slag. CONSTITUTION:The molten iron 2 is introduced into the molten iron pan 1, a desulfurizing agent is charged while agitating by an agitating rod 3, and the molten iron 2 is predesulfurized. The floated desulfurized slag 4 is recovered in a slag pan 6 by a slag dragger 5. The slag 4 is charged into an empty molten iron pan 1 as soon as possible without cooling the slag 4. The molten iron 2 is received in the molten iron pan 1 from an iron ladle 8. The iron in the slag 4 is melted by the agitation at the time of receiving molten iron and the heat retained by the molten iron 2 and recovered in the molten iron 2, and only the slag 4 is floated onto the molten iron 2. The slag 4 is again discharged into the slag pan 6 by using the slag dragger 5, and delivered by a truck 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for recovering metals from desulfurization slag generated during desulfurization treatment of hot metal.

(Prior art) Desulfurization slag generated in the hot metal desulfurization process is scraped and discharged from the pouring ladle by a slag tracker, transported to a predetermined location, and then cooled. A method of recovering bullion by repeatedly crushing and grinding the ore through a sieve using a crushing and grinding machine with a built-in impact iron, and then repeating magnetic separation, crushing and grinding using a rod mill a required number of times to recover the bullion. is publicly known (Special Publication No. 56-2
(Refer to Publication No. 5259) In addition, there is a known metal recovery method in which desulfurization slag is poured into water while still at high temperature, and the slag is pulverized by thermal shock and separated from iron having a different specific heat (Japanese Patent Publication No. 52
(Refer to Publication No.-30243).

Furthermore, a generally known method is to water-cool the desulfurization slag, then repeat the crushing magnetic separation and sieving steps to recover the iron content and reuse it as an iron source.

(Problems to be Solved by the Invention) However, in these conventional techniques, the desulfurization slag (hereinafter sometimes simply referred to as "slag") generated in the hot metal desulfurization process is cooled, then crushed, magnetically sorted, In addition to requiring sieving and complicated work processes, each process requires equipment costs such as crushing equipment, magnetic separation equipment, sieving equipment, etc., increasing processing costs, and the quality of recovered iron is also poor. There were problems such as low iron-coated steel and restrictions on its reuse as an iron source for steelmaking raw materials.

In addition, in the process of scraping and discharging desulfurization slag from the processing vessel, hot metal is scraped out along with slag at the same time, and this amount reaches as much as 1000 kg per charge, which cannot be ignored in actual operations, especially in recent years when production In a situation where there is a strong demand for improved sexual quality, improvements are required.

(Means for Solving the Problems) The present invention has been made to solve these problems, and its gist is to solve the problems in the pouring ladle after desulfurization treatment performed as a preliminary treatment for hot metal. Hot metal desulfurization characterized by charging the generated desulfurization slag into an empty pouring ladle, receiving hot metal into the pouring ladle, and discharging again the desulfurization slag that floated to the surface by stirring during iron reception. This is a method of recovering bullion from slag.

As described above, according to the present invention, the desulfurization slag generated in the hot metal desulfurization process is scraped out, and the discharged desulfurization slag is poured into the converter while it is hot without being cooled, that is, as soon as possible. The desulfurized slag is once charged into an empty pouring ladle and reddled, and the desulfurized slag is received from a hot metal ladle (torpedo, etc.) while being reddled.

The previously charged desulfurization slag contains base iron that was scraped out and discharged together with the desulfurization slag, but it is melted by the high heat of the receiving pig iron, and the desulfurization slag is melted by the high heat of the receiving pig iron. It is separated from the slag and only the desulfurized slag floats to the surface. This floating desulfurization slag is scraped out again, discharged into a slag pot, and transported to a slag processing station. Compared to the first scraping of desulfurization slag, the iron content of the slag is reduced to 20-30%.

As described above, the present invention does not require the complicated process and work of cooling the desulfurization slag discharged after the desulfurization treatment, and recovering the base iron by crushing, magnetic separation, and sieving. First, the base iron in the desulfurization slag can be recovered with a high yield.

(Function) Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIGS. 1(A) to 1(F) are schematic explanatory diagrams sequentially showing steps for recovering base iron from hot metal desulfurization slag according to the present invention.

As shown in FIG. 1(a), the desulfurization treatment is performed while stirring the hot metal 2 charged in the pouring iron H41 with the stirring rod 3, and desulfurization slag 4 is generated and floats above the hot metal 2.

Such desulfurization treatment and the desulfurization agent used therein are already well known. When the desulfurization treatment of the hot metal is completed, as shown in FIG. During scraping, some of the hot metal is also scraped out. According to the method of the present invention, the scraped desulfurization slag 4 is removed from the empty space after pouring hot metal into the converter as quickly as possible without being cooled, as shown in FIG. 1 (c). It is charged into a pouring ladle and re-dolled. It is more effective to charge the charged desulfurization slag in multiple charges, at least 2 to 4 charges at once.

Next, as shown in FIG. 1(d), the desulfurization slag 4 is charged and the hot metal 2 is received from a hot metal ladle 8 such as a torpedo into the iron pouring ladle 1 which is being re-addressed. By stirring during pig iron receiving,
The desulfurization slag 4 charged into the hot metal pouring ladle 1 and being reladled is divided into desulfurization slag alone and slag discharged together with the hot metal from the hot metal ladle 8 such as a torpedo, due to the difference in specific gravity due to the melting of the contained base iron by the retained heat of the hot metal. floats on top of the hot metal. The floating slag I is
As shown in FIG. 1(E), the slag is scraped out and discharged into a slag pot 6. Since the slag treated and discharged in this manner contains a large amount of sulfur, it is transported to a predetermined location such as a slag yard by a slag transport vehicle 9, as shown in FIG. on the other hand,
The hot metal whose slag has been roughly discharged in this way is again subjected to the desulfurization step (a), and the previous treatments are repeated in sequence.

Figure 2 (a), mountain) shows the preliminary slag, that is, the rough slag, which is carried out prior to the desulfurization treatment in the present invention.
The slag at this time is carried out by the above-mentioned slag carrying vehicle 9. Although this preliminary slag is carried out for the purpose of removing blast furnace slag, etc., it may be used instead if the steps (2) and (e) in FIG. 1 described above are performed.

As described above, the method for recovering base iron from hot metal desulfurization slag according to the present invention has a great effect on reducing processing costs by simplifying the process without going through complicated processes such as crushing desulfurization slag, magnetic separation, and sieving. It is something that you have. What's more, the practical benefits are great, including a significant reduction in hot metal loss.

EXAMPLE As mentioned above, the present invention was carried out according to the process order shown in FIGS. 1(A) to 1(F).

Hot metal of 200 to 290 T was poured into the pouring ladle 1, and after performing preliminary slag removal as shown in FIG. 2, desulfurization treatment was performed. The desulfurization slag 4 that has surfaced during the desulfurization process is scraped out by the slag tracker 5 and discharged to the slag 5i46, and the desulfurization slag 4 remains hot without being cooled and is poured into the converter in an empty pouring ladle 1. I loaded it into the tank and used it as a relay.

As shown in Table 1, this iron pouring & f41 is for 2 ch.
The amount of desulfurization slag charged was changed for one charge and one charge for four charges, and the hot metal was then poured into the pouring ladle to recover the bare steel. Incidentally, the slag resulting from the coarsely discharged slag at this time was carried out by a slag transport vehicle in the conventional manner.

The results are also summarized in Table 1. As shown in the lifting table, multiple charges of desulfurized slag are poured into an empty pouring pot, and after the hot metal is discharged, the slag from the coarse waste slag that floats to the surface due to the difference in specific gravity is removed. The amount of recovered steel was confirmed by scraping it out again and actually measuring the weight at each step.

As is clear from Table 1, 0.6 per charge of desulfurization slag
We were able to recover 6 to 0.8 tons of base iron.

(Effects of the Invention) As described above, according to the method of recovering bare metal from desulfurization slag according to the present invention, by performing re-dolling and re-raking of the desulfurization slag, efficient recovery of bare metal can be achieved easily. It can be carried out according to the process and operation, prevents hot metal loss, and can be processed hot, so it is possible to save heat sources and reduce processing such as crushing, magnetic separation, and sieving for recovering steel, making it possible to improve industrial performance. It has a great effect.

[Brief explanation of the drawing]

FIGS. 1(A) to 1(F) are schematic explanatory diagrams showing an embodiment of the present invention in the order of steps; and FIG. 2 is a schematic explanatory diagram showing each step of preliminary sludge removal. 1: Pour iron! lit 3: Stirring rod 4: Desulfurization slag 5: Slag trough car 6; Slag pot
8: Hot metal pot 9: Export vehicle

Claims (1)

[Claims] After charging the desulfurization slag generated in the pouring ladle after the desulfurization treatment performed as a preliminary treatment of the hot metal into an empty pouring ladle, the hot metal is received into the pouring ladle, and by stirring during the pouring. A method for recovering metal from hot metal desulfurization slag, characterized by discharging the floated desulfurization slag again.