JP5633444B2 - Method for melting converter furnace deposit metal - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for melting converter furnace deposit metal for melting molten metal scattered in a converter and sprayed at the converter furnace.

  In the converter, by repeatedly performing blow smelting, molten iron, molten steel, etc. scattered near the furnace port are deposited as a metal, and the furnace port becomes narrower. Therefore, in order to stably operate the converter, the metal deposited at the furnace port (melting of the furnace port deposit) is constantly melted.

  At that time, in order to make effective use of the melted furnace mouth deposit metal, the hot metal for the next charge is applied during the charge process (from the end of the previous charge process until the start of the next charge process). After charging, using the top blowing oxygen lance used in blowing, oxygen is blown to the furnace mouth deposit metal to melt the furnace mouth deposit metal, and the molten furnace mouth deposit metal is melted into the hot metal in the furnace. To be mixed.

  However, when melting the furnace mouth deposited metal by blowing oxygen from the top blowing oxygen lance to the furnace mouth deposited metal with the hot metal charged, the oxygen for melting the furnace mouth deposited metal and the Since the hot metal reacted with it to generate black smoke (rarely red smoke), the supply rate and total supply amount of oxygen for melting furnace deposits were limited. As a result, the amount of furnace mouth deposit metal that can be melted within the limited time between charge processes was limited.

  On the other hand, there is a prior art (for example, Patent Document 1) for spraying cooling water and / or spraying mist from the upper part of the furnace port toward the furnace port for preventing black smoke at the time of hot metal charging.

  In addition, as for the prevention of red smoke during hot metal charging, prior art (for example, Patent Document 2) that controls the oxygen concentration in the receiver (such as a ladle) and applies water spray to the molten iron flow, or hot metal charging There is a prior art (for example, Patent Document 3) in which an inert gas such as nitrogen or water vapor is blown into a container (a ladle or the like).

JP 2005-087992 A JP 2002-003919 A JP-A-9-96492

  However, as described in Patent Document 1 and Patent Document 2, in the case of a method using sprayed water, there is a risk of a steam explosion due to contact between the sprayed water and a high-temperature melt (molten metal), which is problematic in terms of safety. is there. Furthermore, there is a problem that a control means for controlling the oxygen concentration in the receiver is required and the cost is increased.

In addition, as described in Patent Document 3, in the case of a method using an inert gas, for example, an inert gas of about 20,000 Nm ³ / H is required on a ladle scale of 150 tons, and the inert gas is instantaneously supplied. Therefore, it is not economical and practical.

  Moreover, in the first place, it is difficult to install a spray water supply device and an inert gas supply device in the converter equipment in terms of equipment space.

  The present invention was made in view of the circumstances as described above, and after the hot metal was charged into the converter, the hot metal was charged into the converter before the hot metal blowing was started. Therefore, when melting oxygen from the top blown oxygen lance to the furnace mouth deposit metal, it is possible to efficiently dissolve the furnace mouth deposit metal while preventing the generation of black smoke and red smoke safely and economically. An object of the present invention is to provide a method for melting converter furnace deposit metal.

  In order to solve the above problems, the present invention has the following features.

  [1] After the hot metal is charged into the converter and before the hot metal blowing is started, the furnace is charged with oxygen from the top blowing oxygen lance to the furnace mouth deposit metal while the hot metal is charged. When melting the mouth deposit metal, the molten iron is charged into the converter, and then a part or all of the auxiliary raw materials and / or scrap used in the blowing of the molten metal is put into the converter, and then the furnace port deposition is performed. A melting method for converter furnace deposit metal, characterized by melting metal.

[2] The cross-sectional area of the straight body of the converter is S (m ² ), and the amount of auxiliary raw materials and the amount of scrap added to the scrap metal are charged after the molten iron is charged and before melting of the furnace deposit metal is started. When the total amount of raw material equivalent is W (kg),
Secondary material equivalent amount of scrap (kg) = scrap amount (kg) / 3
As
W / S ≧ 40
The method for melting converter furnace deposit metal as described in [1] above.

  In the present invention, when the hot metal is charged into the converter, oxygen is blown from the top blown oxygen lance to the furnace mouth deposit ingot to melt the furnace mouth deposit ingot. Since the furnace mouth deposit metal is melted after a part or the whole of the furnace is put into the converter, the surface of the hot metal in the furnace is covered with the added secondary materials, etc. The reaction between the oxygen for melting the mouth deposit and the hot metal in the furnace is cut off, and the generation of black smoke and red smoke can be prevented safely and economically. As a result, it is possible to eliminate restrictions on the supply rate and total supply amount of oxygen for melting furnace-hole deposited metal, and increase the amount of melted (recovered) furnace-hole deposited metal.

It is a figure which shows one Embodiment of this invention. It is a comparison figure of the generation level of black smoke of an example.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an embodiment of the present invention.

  As shown in FIG. 1, in this embodiment, after the molten iron 11 is charged into the converter 10 and before the blowing of the molten iron 11 is started, the top blowing oxygen lance is applied to the furnace deposit metal 20. It is assumed that oxygen 22 is blown from 21 to dissolve the furnace deposit metal 20, and in this case, after the molten iron 11 is charged into the converter 10, auxiliary materials (for example, dolomite, Lime etc.) 12 is put into the converter 10 in advance, and then oxygen 22 is blown from the top blown oxygen lance 21 to the furnace deposit 20 to melt the furnace deposit 20. ing.

  The work procedure is as follows.

  (S1) The precharge process is terminated.

  (S2) First, scrap (not shown) is charged into the furnace as the main raw material.

  (S3) Next, the hot metal 11 of the charge is charged into the furnace.

  (S4) Next, a predetermined amount of auxiliary material (for example, dolomite, lime, etc.) 12 is charged in advance into the furnace from an auxiliary material charging hopper (not shown).

  (S5) Then, oxygen 22 is injected from the top blowing oxygen lance 21 to dissolve the furnace port deposited metal 20.

  (S6) Then, the charge process is started.

  As a result, in this embodiment, the entire surface of the hot metal 11 in the furnace is covered with the pre-added auxiliary raw material 12 so that the reaction between the sprayed oxygen 22 and the hot metal 11 in the furnace is cut off. The generation of smoke and red smoke can be prevented safely and economically.

  As a result, it is possible to eliminate restrictions on the supply rate and total supply amount of the oxygen 22 for dissolving the furnace mouth deposited metal 20 and increase the amount of dissolved (recovered amount) of the furnace mouth deposited metal 20. Become.

  In addition, the quantity of the auxiliary | assistant raw material 12 thrown in in said (S4) should just be the quantity which the whole surface of the hot metal 11 in a furnace is covered.

For example, when the cross-sectional area of the straight body portion of the converter 10 is S (m ² ) and the amount of the auxiliary raw material 12 to be input in (S4) is W (kg), the auxiliary raw material input ratio W / S is
W / S ≧ 40 (1)
What should be done.

  Here, the value calculated from the diameter (design value) of the straight body part of the converter may be used for the cross-sectional area S of the straight body part.

  Further, a part or all of the scrap charged in (S2) may be charged in (S4), and the scrap and the auxiliary material 12 may cover the surface of the hot metal 11 in the furnace.

In that case, the amount of scrap added in (S4) above converted into a secondary raw material (a secondary raw material equivalent amount of scrap) is calculated by the following equation (2), and the secondary raw material equivalent amount of the scrap and the above amount are calculated. The total value with the secondary raw material 12 may be set to W in the above (1) as the secondary raw material equivalent input amount.
Secondary material equivalent amount of scrap (kg) = Scrap amount (kg) / 3 (2)

  In some cases, the auxiliary material may not be charged in (S4), and the surface of the hot metal 11 in the furnace may be covered with only the scrap charged in (S4).

  In that case, the amount of scrap equivalent to the raw material calculated by the above equation (2) may be used as W in the above (1).

  Therefore, in the above equation (1), W can be referred to as a secondary raw material equivalent input rate, and the secondary raw material input rate W / S can also be referred to as a secondary raw material equivalent input rate W / S.

  Examples of the present invention will be described.

As an example of the present invention, based on the above-described embodiment of the present invention, the top and bottom blowing with a hot metal charging amount of 300 Ton, a furnace height of 12 m, and a furnace diameter of 7.8 m (straight body section area S = 48 m ² ) After the molten iron is charged into the converter and before the melting of the furnace mouth deposited metal of the converter is started (that is, in (S4) above), the amount of auxiliary materials and scrap shown in Table 1 are set. The furnace mouth deposit metal 20 was melted.

  As shown in Table 1, in Example 1 of the present invention, only the auxiliary raw material 12 was added in the above (S4), and the auxiliary raw material equivalent input ratio W / S was set to 42. In Invention Example 2, only the auxiliary raw material 12 was added in the above (S4), and the auxiliary raw material equivalent charging ratio W / S was set to 125. Further, in Example 3 of the present invention, only the scrap was charged in the above (S4), and the auxiliary raw material equivalent charging ratio W / S was set to 42. In Invention Example 4, the auxiliary material and scrap were added in (S4) above, and the auxiliary material equivalent input ratio W / S was set to 125.

  On the other hand, as a comparative example, the melting of the furnace mouth deposited metal 20 was performed without adding the auxiliary material 12 and scrap as described above.

  In Examples 1 to 4 of the present invention and the comparative example, there was no restriction on the supply rate or supply amount of the oxygen 22 for dissolving the furnace mouth deposited metal 20.

  Regarding the results, the generation level of black smoke in each case is shown in FIG.

  As shown in FIG. 2, in the comparative example, the generation of black smoke is at a level that can be confirmed even outdoors, and the melting of the furnace mouth deposited metal 20 was stopped halfway.

  On the other hand, in the present invention example 1 and the present invention example 3, the level is lower than the level at which generation of black smoke can be confirmed, and the melting of the furnace mouth deposited metal 20 was possible.

  Further, in the present invention example 2 and the present invention example 4, the generation of black smoke was almost not recognized, and the melting of the furnace mouth deposited metal 20 was possible without any problems.

  As a result, in the present invention example, it is possible to eliminate restrictions on the supply speed and the total supply amount of the oxygen 22 for melting the furnace deposit deposited metal as in the prior art. It was confirmed that the supply rate of oxygen 22 and the total supply amount can be increased.

  Therefore, by applying the present invention, the supply rate of the oxygen for melting the furnace mouth deposited metal 22 is 1.5 times the conventional rate and the total supply amount is 1.6 times that of the conventional material, As a result, the recovery amount of the furnace mouth deposited metal 20 increased compared to the conventional case, and a yield improvement of 1.7% could be obtained.

DESCRIPTION OF SYMBOLS 10 Converter 11 Hot metal 12 Auxiliary material 20 Furnace deposit metal 21 Top blown oxygen lance 22 Oxygen (Oxygen for melting furnace deposit metal)

Claims (2)

  After the hot metal is charged into the converter and before the hot metal blowing is started, with the hot metal being charged, oxygen is blown from the top blowing oxygen lance to the furnace mouth deposit metal, When melting the gold, the molten iron is charged into the converter, and then a part or all of the auxiliary raw materials and / or scrap used in the blowing of the molten metal is put into the converter, A method for melting converter furnace deposit metal, characterized by melting. The cross-sectional area of the straight body of the converter is S (m ² ), the amount of secondary raw material and the amount of scrap secondary raw material converted that are charged after the molten iron is charged and before the melting of the furnace deposit metal is started. When the total amount of is W (kg),
Secondary material equivalent amount of scrap (kg) = scrap amount (kg) / 3
As
W / S ≧ 40
The method for melting converter furnace deposit deposited metal according to claim 1, wherein:

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