WO2002101096A1

WO2002101096A1 - Method of preliminarily processing converter type hot metal

Info

Publication number: WO2002101096A1
Application number: PCT/JP2002/005563
Authority: WO
Inventors: Keiji Shin; Masao Yamauchi; Syunsuke Nagata; Tamotsu Matsumura
Original assignee: Nippon Steel Corporation
Priority date: 2001-06-06
Filing date: 2002-06-05
Publication date: 2002-12-19
Also published as: JP4718722B2; JP2002363630A

Abstract

A method of preliminarily processing converter type hot metal that has higher productivity. A method of preliminarily processing converter type hot metal for p-removal refining and C-removal refining of molten metal, characterized in that in effecting C-removal refining, molten metal having its P removed by the converter that is charged into the converter for C-removal refining, or molten metal put on standby in advance and having its p removed in some other converter or a similar facility, is charged into the converter to continue C-removal refining.

Description

Description Converter type hot metal pretreatment method Technical field

The present invention relates to a dephosphorization scouring (hereinafter, referred to as de-P scouring) mainly for dephosphorization in a converter or a converter type steelmaking furnace (hereinafter, referred to as a converter), and a decarburization mainly for decarburization. The present invention relates to a converter-type hot metal pretreatment method for refining (hereinafter referred to as de-C refining). Background art

Conventionally, so-called hot metal pretreatment, such as dephosphorization of hot metal, has been carried out using a torpedo car or the like that transports hot metal from a blast furnace to a converter. However, techniques for hot metal pretreatment in converters are becoming widespread. For example, a plurality of converters as described in Japanese Patent Application Laid-Open No. 6-73425 are used, and one of the converters is used only for de-P refining and the other is used for de-P refining. There is a so-called dedicated furnace type converter-type hot metal pretreatment method used as a C furnace. In addition, after using one converter as disclosed in Japanese Patent Application Laid-Open No. 11-181512 to remove the P from the hot metal from the blast furnace, the molten metal was discharged once, and as a result of the P removal, There is a so-called converter type hot metal pretreatment method of so-called converter type in which the de-P slag is discharged, the de-P-purified molten metal is charged again into the same converter and de-C-refining is performed. In any case, the hot metal pretreatment can be performed in the converter, and the advantages such as equipment consolidation are great.

However, in the converter type pre-purification as described above, charging, scouring, tapping, etc. are required twice for both de-P and de-C refining, occupying the converter per charge. Avoiding longer time As a result, productivity has declined, and a converter-type hot metal pretreatment method that further improves productivity is needed.

Figure 3 shows an overview of the cycle time in the same furnace type hot metal pretreatment method. In the same furnace type hot metal pretreatment method, after de-P scouring, after tapping the P-free iron into a pan, the pot is moved from the bottom of the furnace to the charging side, and the transportation time for lifting to the charging position is appear. During that time, the converter performs waste after the tapping, and a non-operating time is generated from the end of the waste to the charging of the molten metal.

On the other hand, Fig. 4 shows an example of the refining schedule of a dedicated furnace type hot metal pretreatment method.

Normally, the cycle time from charging of de-P refining to waste is shorter than the cycle time of de-C refining. Therefore, in the dedicated furnace type hot metal pretreatment method, since the refining pitch of the P-removing furnace is matched with the pitch of the C-removing furnace, the non-operating time of the converter between the refining of the P-removing furnace is as shown in the figure. appear. Disclosure of the invention

The present invention provides a converter-type hot metal pretreatment method with high productivity that effectively utilizes the non-operation time of the converter.

The present invention has been made to solve the above problems, and the gist thereof is as follows.

(1) In a converter-type hot metal pretreatment method that performs de-P refining and de-C refining of molten metal, during de-C refining, the P furnace is charged into the converter for de-C refining. The converter is characterized in that the molten metal that has been removed or the molten metal that has been de-P treated in a converter or other similar equipment and that has been placed on standby in advance is charged into the converter and the C-refining is continued. Furnace hot metal pretreatment method. (2) In the converter-type hot metal pretreatment method in which the molten metal that has been de-P-refined is de-C-purified in the converter after the molten metal is de-P-refined in the converter, For this reason, the molten metal charged into the converter is a molten metal (hereinafter, molten metal B) other than the molten metal (hereinafter, molten metal A) which has just been de-P scoured and discharged in the converter. Converter type hot metal pretreatment method.

(3) The molten metal B charged into the converter for de-C refining is a molten metal that has been de-P-purified in the converter (hereinafter, molten metal A ') prior to the molten metal A. (2) The converter type hot metal pretreatment method according to (2).

(4) The molten metal B charged into the converter for de-C refining is molten metal de-P-refined in another converter (hereinafter, molten metal C). (2) 2. A converter type hot metal pretreatment method according to item 1.

(5) In the converter type hot metal pretreatment method, after the molten metal is de-P-refined in the converter and discharged, and then the de-P-refined molten metal is de-C-refined in the converter or another converter. Then, after the molten metal is removed from the melt in the converter and the molten metal is discharged, the molten metal (melt C) that has been removed from the melt and discharged from the other converter is charged into the converter, and the molten metal is removed from the melt. The molten iron (Molten A) that has been de-P-refined in the converter and discharged from the converter is charged into another converter and de-C-purified. Processing method.

(6) A converter-type hot metal pretreatment method in which the molten metal that has been de-P-purified is de-C-purified in the converter or another converter after the molten metal is de-P-refined in the converter and discharged. In the above, after removing the P and refining in the converter, the molten iron is charged into the converter or another converter, the ordinary converter is refined and the steel is removed, and then the P-refined molten metal is removed. A converter-type hot metal pretreatment method characterized by charging and decarbonizing.

(7) After removing the molten metal in the converter, In the converter-type hot metal pretreatment method for removing de-P-purified molten metal in a converter, de-P-refining the molten metal in the converter-type hot metal pretreatment method.After that, ordinary hot metal is charged into the converter, and then ordinary converter refining is performed. A method for preheating a converter type hot metal, which comprises charging a molten metal (melt A) that has been de-P-refined in the converter and then discharged, and de-C-refined.

(8) In the converter or another converter, after the molten metal is removed from the molten metal in the converter and the molten metal is discharged, the molten iron is subjected to de-P refining in the converter or another converter. In the converter, the molten metal is de-P-refined and discharged. The molten metal (Molten A) is charged into another converter and de-C-refined, and ordinary molten iron is charged into the converter. A converter-type hot metal pretreatment method characterized by charging a molten metal (melt C) that has been de-P-purified in another converter, and then de-C-refined after the steel has been refined in a converter.

(9) After removing the molten metal in the converter and removing the molten metal from the furnace, the molten metal is de-P-refined in the converter or another converter. At least one of the converters is a converter for de-P, and the other converter is a converter for de-C.

De-P refining is continuously performed in the P-removal converter, and when the non-operating time of the P-removal converter exceeds the cycle time required for ordinary hot metal refining, the P-removal is performed. A converter-type hot metal pretreatment method characterized by performing ordinary converter refining in a converter.

(10) After removing the molten metal in the converter and removing the molten metal from the furnace, the molten metal is de-P-refined in the converter or another converter. At least one of the converters is a converter for de-P, and the other converter is a converter for de-C. At the same time, the de-P refining is performed, and the molten metal that has been de-P-refined in the de-C converter is (Molten A). The molten metal (Molten C) de-P refined in the P-removing converter is alternately charged and de-C refined, and the P-removing converter performs de-P refining. A converter-type hot metal pretreatment method characterized by performing ordinary converter refining for refining ordinary hot metal.

(11) The molten metal de-P-refined in the C-free converter and the molten metal de-P-refined in the P-free converter are alternately charged into the C-free converter. In the de-C-refining, the de-C-removing converter de-P-refined the molten metal (melt C) that has been de-P-refined in the P-removing converter, and then de-P-refined in the de-C-removing converter. The converter-type hot metal pretreatment method according to (10), wherein the molten metal (molten metal A ′) is de-C-purified. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing an embodiment of the converter type hot metal pretreatment method of the present invention. (Part 1 )

FIG. 2 is a diagram showing an embodiment of the converter type hot metal pretreatment method of the present invention. (Part 2)

FIG. 3 is a diagram showing a refining cycle of the same furnace type.

FIG. 4 is a diagram showing a refining schedule of a dedicated furnace type. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described specifically.

As shown in Fig. 3, in the hot metal pretreatment method of the same furnace type, the molten metal discharged from the pot after de-P refining in the converter is de-C-refined. To the charging position of the converter. During this transfer process, the converter generates downtime. On the other hand, the present invention deals with the following method.

That is, after de-P scouring is completed in the converter, the scoured molten metal (hereinafter, referred to as Rather than waiting for the molten metal A) to be discharged and transported to the charging position of the converter, the de-P-refined molten metal is separately kept at the charging position of the converter, and Immediately after the de-P scouring in the furnace is completed and the discharge of the converter is completed, the separately de-P-purified molten metal (Molten B) that has been put on standby is charged into the converter, and C scouring.

The molten metal (hereinafter, “molten A”) refers to the charge refined in the converter.

That is, as shown in the patterns 1 and 2 in FIG. 1, after the molten metal is removed from the molten metal in the converter and the molten metal is discharged, the molten metal removed from the molten metal is continuously removed in the converter. In the converter-type hot metal pretreatment method for C-refining, other than the molten metal charged into the converter for de-C refining, which is de-P-refined in the converter and discharged (hereinafter, molten metal A) The other molten metal (hereinafter, “Molten B”). This allows the converter to operate effectively while the molten metal A de-P-purified in the converter is moving for recharging.

In addition, as shown in Pattern 1 in FIG. 1, in claim 3, in claim 2, the other molten metal B charged to the converter for de-C refining is added to the molten metal A. Prior to that, the molten metal was de-P-refined in the converter (hereinafter referred to as molten metal A ').

Further, according to claim 4, as shown in pattern 2 of FIG. 1, in claim 2 (pattern 1 of FIG. 1), the other molten metal B charged into the converter for de-C purification is Molten metal that has been de-P scoured in another converter (hereinafter, molten metal C).

In this way, by charging the de-P-purified molten metal separately from the molten metal of the charge into the converter and performing the C-refining, the operation rate in the converter can be increased, Also, this method can be performed mutually between a plurality of converters. That is, in claim 5, as shown in pattern 2 of FIG. 1, after the molten metal was removed from the melt in the converter, the molten metal was discharged, and then the molten metal was removed from the melt in the converter or another converter. In the converter-type hot metal pretreatment method in which the molten metal is de-C-purified, the molten metal is de-P-refined in the converter and discharged, and then de-P-refined in another converter to discharge the molten metal. The molten metal (Molten C) is charged and de-C scouring is performed, and the molten metal (Molten A) de-P scoured and discharged in the converter is charged into another converter and de-molten. C to refine. In this way, multiple converters can mutually increase efficiency.

As described above, in the above claims 2 to 4, after the molten metal is de-P-purified in the converter and discharged, the de-P-purified molten metal that is de-C-purified in the converter is converted into the molten metal of the charge ( By replacing the molten metal A) with a molten metal that has been de-P-purified separately (melt B), in claim 5, the molten metal that is de-C-purified in the converter is de-P-purified in another converter. In addition to melting the molten metal, the molten metal de-P-purified in the converter is de-C-purified in another converter, thereby eliminating the non-operating time caused when the de-P-purified molten metal is transported to the charging position. Things.

Furthermore, in the present invention, the non-operating time caused by this transportation is replaced with the use of ordinary molten iron instead of the separate introduction of the P-refined molten metal and the removal of the C-refining, followed by ordinary converter refining. This can be resolved. In other words, claim 6 is a converter-type hot metal reserve in which the molten metal that has been de-P-refined is de-C-refined in the converter or another converter after the molten metal is de-P-refined in the converter and discharged. In the treatment method, after de-P refining in the converter and tapping, ordinary hot metal is charged into the converter or another converter, ordinary converter refining and tapping, and then de-P refining. The molten metal is charged and decarbonized. This method can respond by placing ordinary hot metal on standby as necessary, which is extremely useful for eliminating downtime. In addition to being effective, it is also effective in controlling slag contamination as described below. Note that ordinary converter refining means refining ordinary molten iron into molten steel in a converter (also abbreviated as N refining). However, ordinary hot metal means hot metal that is not subjected to P removal treatment.

That is, claim 7 is a converter-type hot metal pretreatment method in which after the molten metal is de-P-refined in the converter and the molten metal is discharged, the de-P-refined molten metal is further de-C-refined in the converter. After de-P refining and tapping, the molten metal is continuously charged with the ordinary molten iron into the converter, and then subjected to ordinary converter refining and tapping. (Molten A) is charged and decarbonized.

As shown in pattern 5 in FIG. 2, after de-P refining in the converter, ordinary hot metal is made to stand by at the charging position of the converter in advance, and after completion of the discharge of the converter, The ordinary molten iron is charged, ordinary converter refining is performed, and tapping is performed. Then, in the converter, the molten metal that has been de-P refined first (the molten metal A,) is charged and de-C refined. Things.

That is, in pattern 5 in Fig. 2, after de-P refining of pattern 1, instead of another de-P refining molten metal, ordinary hot metal is charged and ordinary converter refining is performed. It can be seen that the refined molten metal (Molten A ') is de-C-purified. This will eliminate downtime and increase operational flexibility.

Further, the above method can be performed between a plurality of converters.

In other words, claim 8 is a hot metal pretreatment for removing the P from the molten metal in the converter and discharging the molten metal, and then removing the de-P-purified molten metal from the molten metal in the converter or another converter. In the converter, the molten metal is removed from the furnace by de-P refining, and the molten metal is supplied to another converter. In addition, ordinary molten iron is charged into the converter, and the ordinary converter is refined. Then, the molten metal (Molten C) that has been de-P scoured in another converter is charged, and de-C scouring is performed. It is what you do.

This is a pattern that is a compromise between the methods of claim 4 (pattern 2 of FIG. 1) and claim 10 (pattern 5 of FIG. 2), as shown in pattern 6 of FIG. One of the furnaces (B furnace in pattern 2 in Fig. 1) removes P and scours the molten metal, and supplies the molten metal to another converter (A furnace in pattern 2 in Fig. 1) to remove C. In the converter, after the slag is discharged, ordinary hot metal that has been previously placed in a standby position at the charging position of the converter is charged, the ordinary converter is refined, and tapping is performed. Next, in the converter, the molten metal de-P-purified in another converter is charged and de-C-purified. This processing pattern is performed in each furnace.

With this method, it is possible to eliminate the non-operating time due to the processing time shift and the transport time among a plurality of converters, and to expand the degree of freedom of operation.

Next, as described in FIG. 4, in the converter type hot metal pretreatment method of the dedicated furnace type, the cycle time of the de-C refining and the de-P refining is different. Non-operating time occurs on the P-free side. In the present invention, this non-operation time is eliminated by the following method.

That is, the invention of claim 9 is a hot metal pretreatment in which the molten metal de-P-refined in the converter or another converter is de-C-refined in the converter or another converter. In a converter-type hot metal pretreatment method of a dedicated furnace type in which at least one of the multiple converters is used as a converter for removing P and the other converter is used as a converter for removing C, In the P converter, the P removal is continuously performed, and when the non-operating time of the P removal converter is longer than the cycle time required for ordinary converter refining of the normal molten iron, the P removal is performed. The furnace is used for ordinary converter purification.

As shown in Pattern 3 in Fig. 1, this is a converter for de-C conversion (A furnace). In the converter for de-P (B furnace), the de-P converter is continuously de-C-purified, and the non-operating time is concentrated. In the mining, the normal converter refining is sandwiched between the de-P refining. As a result, it is possible to effectively contribute to the production of non-operating time due to the difference in cycle time between de-P scouring and de-C scouring.

For example, in pattern 3 in Fig. 1, the P-removing converter (B furnace) continuously performs 5 charges of P-free refining, and the cycle time difference from C-free refining accumulates. Since non-operating time for one ordinary converter refining is generated, one ordinary converter refining can be performed for every five charges after de-P refining, and the non-operating time can be eliminated.

In addition, in pattern 3 in Fig. 1, the normal furnace converter 1 charge was applied to the hot metal pretreatment 5 charges. For example, the continuous converter (CC) that receives the refined molten copper If the continuous steelmaking machine (CC) that receives the hot metal pretreated molten steel, that is, the low phosphorus steel, is separated, the number of charges supplied to the two continuous steelmaking machines will be unbalanced.

In this case, even in the de-C converter of pattern 3 in Fig. 1, de-P purification is performed at an arbitrary timing. That is, claim 10 is a special furnace type in which the hot metal pretreatment is performed by using at least one of the plurality of converters as a converter for removing P and the other converter as a converter for removing C. In the converter-type hot metal pretreatment method, the de-P refining is performed also in the de-C converter, and the molten metal de-P-purified in the de-C converter is added to the de-C converter. (Molten A) and the molten metal (Molten C) de-P refined in the P-removing converter are alternately supplied to de-C refining, and P-removing is performed in the P-removing converter. During the non-operation time, ordinary converter refining for refining ordinary hot metal is performed. As shown in pattern 4 of Fig. 2, at least one of the converters is a converter for de-P (B furnace) and the other converter is a converter for de-C (A In the converter for de-P (B furnace), de-P scouring is carried out while sandwiching the ordinary converter as shown in pattern B in Fig. 1, pattern 3. On the other hand, the de-C converter (A furnace) mainly performs de-C refining and de-P refining at any time. Here, in pattern 4 in Fig. 2, the converter for C removal is a dedicated furnace that mainly performs C removal, but unlike pattern 3 in Fig. 1, P removal is also performed at an arbitrary timing. Therefore, in the outline of pattern 4 in Fig. 2 and pattern 4-2 in Fig. 2 described later, it is treated as the same furnace and described as the same furnace-dedicated furnace mixture.

In this way, the pattern for removing P from the C-removing furnace side is defined as follows. In the converter for removing C, the molten metal removed in the P-removing converter and in the converter for removing C are removed. The molten metal is charged alternately to remove C. As a result, the processing ratio of the ordinary steel and the low-phosphorus steel is almost the same.

However, in the case of pattern 4 in FIG. 2, the non-P converter may have a non-operating time. In such a case, priority should be given to the molten metal that has been de-P-refined in the P-P converter.

That is, in claim 11, the molten metal de-P-purified in the C-free converter and the molten metal de-P-purified in the P-free converter are alternately placed in the C-free converter in claim 10. At the time of charging and de-C refining, in the de-C de-converter, the molten metal de-P-refined in the de-P converter is de-C-refined, and then the temporarily-removed de-C converter is placed. It is a process in which molten metal (Molten A ') that has been de-P-purified in a furnace is charged and de-C-purified. This is because, as shown in pattern 4-2 in Fig. 2, the molten metal that has been de-P-refined in the C-removal converter is temporarily placed, and the molten metal is removed by the P-removal converter. P Refined molten metal (Molten C) Is charged, de-C refining and tapping are performed, and then the temporarily placed de-P-purified molten metal (Molten A,) is de-C refined. As a result, the non-operating time on the P-converter side can be eliminated.

At this point, immediately after de-P scouring, if de-C scouring is performed in the same converter immediately, it will adhere to the furnace and return P (re-phosphorus) to the molten metal from slag with a high P content. The method described in any one of claims 6 to 11, for example, as shown in pattern 4, 4-2, 5 or 6 in FIG. By sandwiching the operation, slag with a low P concentration is generated, the slag attached to the furnace with a high P concentration is washed, and it is possible to suppress the recovery of P in the subsequent de-C refining. There are advantages.

As can be seen from the examples of Pattern 1 to Pattern 3 in FIG. 1 and Pattern 4 to Pattern 6 in FIG. 2, the point of the present invention is that the hot metal is removed from the molten P After that, the other furnace is charged with the de-P molten metal of another charge and de-C refined, or the molten iron is de-P refined, and then the de-P molten metal is discharged, and then the converter is put into the converter. In addition, normal molten iron is charged, the converter becomes a normal converter, copper is removed, and then other molten metal from other channels is charged and decarbonized.

The effects of the method of the present invention, such as the improvement of productivity and the suppression of contamination of molten metal by slag (suppression of P), are shown together with the pattern examples of FIGS. Example

Using a converter in actual operation, according to the operation of Pattern 1 in Fig. 1, the molten metal (Molten A,) previously de-P-purified in the converter and the molten metal (P-melted) in other converters C) was used to remove C in the converter. Compared to the conventional hot metal pretreatment method of the same furnace type, the productivity is improved by about 5%. Was. Industrial applicability

ADVANTAGE OF THE INVENTION According to the present invention, in the converter type hot metal pretreatment method, it is possible to improve the operation rate of the converter and improve the productivity, and also to perform sound de-C refining capable of suppressing the recovery P. .

Claims

Range of request

1. In the converter-type hot metal pretreatment method for de-P refining and de-C refining of molten metal, when de-C refining is performed, the P-removing process is performed in the converter that is inserted into the converter for de-C refining. The molten metal that has been de-P treated in a converter or other similar equipment and that has been put on standby beforehand

A converter-type hot metal pretreatment method comprising charging the furnace and continuing C-refining.

2. In the converter-type hot metal pretreatment method in which the molten metal that has been de-P-refined is de-P-refined in the converter and then de-C-refined in the converter,

The molten metal charged into the converter for de-C refining is a molten metal (hereinafter, “Molten B”) other than the molten metal (hereinafter, “Molten A”) that has just been de-P scoured and discharged from the converter. A converter type hot metal pretreatment method characterized by the above-mentioned.

3. The molten metal B charged into the converter for de-C refining is a molten metal that has been de-P-refined in the converter prior to the molten metal A (hereinafter, molten metal A '). The converter-type hot metal pretreatment method according to claim 2, characterized in that:

4. The molten metal B charged into the converter for de-C refining is a molten metal de-P-refined in another converter (hereinafter, molten metal C). A converter-type hot metal pretreatment method as described in the above.

5. In the converter type hot metal pretreatment method, after the molten metal is de-P-refined in the converter and the molten metal is discharged, and then the de-P-refined molten metal is de-C-refined in the converter or another converter.

After de-P scouring the molten metal in the converter and tapping, the molten metal (Molten C) de-P scoured and discharged in another converter is charged into the converter, and de-C refining is performed. At the same time, the molten metal (P Hot water A) is a converter-type hot metal pretreatment method characterized in that it is charged into another converter and decarbonized.

6. In the converter-type hot metal pretreatment method in which the molten metal de-P-refined in the converter or another converter is de-C-refined in the converter or another converter after the molten metal is de-P-refined in the converter.

After de-P scouring in the converter and tapping, the hot metal is charged into the converter or another converter, ordinary converter scouring and tapping, and then the de-P scoured molten metal is removed. A converter-type hot metal pretreatment method characterized by charging and decarbonizing.

7. In the converter-type hot metal pretreatment method for de-P refining the molten metal in the converter and discharging the molten metal, and then in the converter, de-P refining the molten metal,

After de-P scouring and tapping, the converter is charged with ordinary molten iron, ordinary converter scouring and tapping, and then de-P-refined and discharged from the converter. A) A converter-type hot metal pretreatment method characterized in that A) is charged and decarbonized.

8. In the converter or other converter, after the molten metal is removed from the molten metal in the converter and the molten metal is discharged, the molten metal is subjected to the de-P refining and the molten metal is de-C-purified.

In the converter, the molten metal is de-P scoured and discharged, the molten metal (Molten A) is charged into another converter and de-C refined, and ordinary molten iron is charged into the converter. A converter-type hot metal pretreatment method characterized in that after the steel is refined in a normal converter and the steel is tapped, the molten metal (melt C) that has been de-P-purified in another converter is charged and then de-C-refined. .

9. After removing the molten metal in the converter and de-pouring the molten metal, the pre-treatment of de-P-refined molten metal in the converter or another converter is performed in the converter. At least one of them is a converter for de-P In the converter-type hot metal pretreatment method of a dedicated furnace type performed as a de-C converter,

10. After removing the molten metal in the converter and removing the molten metal from the furnace, the molten iron preliminarily treated in the converter or another converter to remove the molten metal that has been de-P-purified is de-C-refined. At least one of them is a converter for de-P, and the other converter is a converter for de-C.

The de-P converter is also de-P-refined in the de-C converter, and the molten metal de-P-refined in the de-C converter (melt A) and the de-P converter in the de-P converter are removed. The refined molten metal (Molten C) is charged alternately and de-C-purified, while the de-P converter is de-P-refined, and during the non-operation time, the ordinary converter for refining ordinary molten iron A converter-type hot metal pretreatment method characterized by performing refining.

11. The molten metal de-P-refined in the converter for de-C and the molten metal de-P-refined in the converter for de-P are alternately charged into the converter for de-C, and then removed. C

In the converter for removing C, the molten metal (molten metal C) which has been de-P-purified in the converter for removing P is de-C-refined, and then the molten metal (melt A which has been de-P-refined in the converter for removing C is melted. 11. The converter-type hot metal pretreatment method according to claim 10, wherein the ') is subjected to de-C refining.