JPS60184611A - Apparatus for treating molten pig iron - Google Patents

Abstract

PURPOSE:To provide the titled apparatus for treating molten pig iron capable of removing Si and P in the molten pig iron with a high rate by blowing at high speed powdery fluxes for removing Si and for removing P simultaneously into molten pig iron flowing in a tapping trough in a reaction zone separated with a skimmer. CONSTITUTION:The molten pig iron discharged from a blast furnace flows in a tapping trough 5, and blast-furnace slag 7' is separated 2 from the molten pig iron with a skimmer 3a. Then the molten pig iron flows successively through reaction zones 4a and 4b. In the reaction zone 4a, the powdery fluxes for removing Si and for removing P are blown at high speed with a carrier gas into the molten pig iron 5 respectively from lances 6a and 6b, and slags 7a and 7b contg. SiO2 and P2O5 are separated with a skimmer 3b. Then the S in the molten pig iron is removed in the reaction zone 4b, and the slag 7c contg. S is separated with a skimmer 3c. The separated slag 7a and slag 7b are put together, and charged into a pot 10a from a trough 9a. The slag 7c is charged into a pot 10b from a trough 9b, and both slags are separately treated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot metal processing apparatus, and in particular to a hot metal treatment using a blast furnace tap trough, which removes impurities in the hot metal by injecting powder flux into the hot metal flowing through the blast furnace tap trough. As for this kind of method for treating hot metal using a blast furnace tap trough, there is known an overlay method in which powder flux is placed on top of the hot metal flowing through the tap trough to treat impurities. however,
In this method, the powder flux is not added well to the hot metal, and the contact between the powder flux and the hot metal is poor.
The first class de-impurity reaction does not proceed quickly, and therefore,
The reaction takes time and requires a very long reaction distance. To avoid this, in the nodding method, even if powder flux is added to the hot metal, it only melts the powder flux and does not involve in reactions such as de-81. At present, the only thing left to do is remove it.

Therefore, in order to improve the removal efficiency of impurities and shorten the processing time, the inventors of the present invention attempted to improve the method of adding powder flux and improve the contact between the added powder flux and hot metal. A variety of studies have been carried out in the past, including research on

As a result, the inventors found that in order to properly add powder flux into hot metal, a lance should be installed above the tap flute.
Powder blanks can be blown into the hot metal flow from this lance using carrier dregs, and the tapping sluice bed area (
In order to prevent wear and tear on the bottom part of the lance, it was found that it is better to install the lance away from the surface of the hot metal flow, and recently filed an application (Japanese Patent Laid-Open No. 330208/1983).

By such blowing, the powder flux penetrated deep into the hot metal bath and came into good contact with the hot metal, and impurities were removed with high efficiency and in a short time. Therefore, from this, it was discovered that it is possible to remove all of these impurities in the tap hole by removing Sl, P, S, etc. one by one, or in some cases, multiple at intervals. .

As a result of further research, the present inventors blow powder flux into the hot metal flow at bath depth H so that the penetration depth Hp or 0.30H≦[p(1,0H). It was discovered that if this method is used, it is possible to sufficiently prevent wear and tear on the taper track section due to powder flux collisions, and it is also possible to stably and highly efficiently remove impurities that have sometimes caused a decrease in efficiency. A hot metal processing method suitable for actual operation was obtained.

The present invention provides an apparatus for carrying out the hot metal treatment method obtained as a result of the series of researches described above, and the taper taper is installed downstream of the slag runner connecting position of the blast furnace taper. One reaction zone partitioned by the two skinmers is provided by installing two skinmers with their lower ends immersed at a distance from each other in the flowing hot metal with a space between them and the bottom surface of the tap flue. In addition, in the one reaction zone, a first lance of a tank for blowing a powder flux for de-SI into the bath iron at a high speed, and a second lance of a tank for blowing a powder flux for dephosphorization at a high speed. The tips of the first and second lances are placed above the surface of the molten pig iron, and further, the tips of the first and second lances are placed on the side wall of the tap iron in the one reaction zone. 1. Hereinafter, the following 15 embodiments will be described. 1, which will be described in detail based on FIG. 161, is a plan view showing the hot metal processing apparatus of the present invention, and FIG.
~2 In Figure 2, 1 is a tap trough of the blast furnace, and downstream of the connection position of the slag trough 2 of the tap trough 1, a reaction zone 4a is formed by skimmers 3a, 3b, and 3C that partition the tap trough 1.
and 4b are formed.

The skinmers 3a to 3C are provided perpendicularly to the tap hole 1, and their lower ends are immersed in the hot metal 5 flowing inside the tap hole 1 with a gap between them and the bottom surface 1a of the tap hole 1. has been done.

Therefore, the hot metal 5 discharged from the blast furnace and flowing through the tap pipe 1 is separated from the blast furnace slag 7' by the skimmer 3a, and flows sequentially down the reaction zones 4a and 4b. The blast furnace slag 7' is discharged through the slag trough 2. Reaction zone 4a
is for removing Sl and P in the hot metal 5, reaction zone 4b is for removing S, and in the reaction zone 4a is a lance 6 for blowing powder flux into the hot metal 5.
Similarly, an appropriate number of lances 6c (two in the figure) are inserted through the gutter cover 11 into the reaction zone 4b. , the lances 6a to 6b and 6C are fixed at their tips to prevent them from being eroded by the slags 7a to 7b and 7C generated by blowing the hot metal 5 and powder flux flowing in the respective reaction zones 4a and 4b. The section is installed so as to be isolated from the surface of the hot metal 5 for an appropriate period of time.

In the lances 6a to 6C, the powder flux for de-S1, the powder flux for de-P, and the powder flux for de-S are supplied to the carrier gas from the refining agent tanks 8a to 8C installed outside the tap flute l, respectively. "Ni": The first thing that is supplied. These powder fluxes are blown at high speed into the hot metal 5 flowing in the respective reaction zones 4a and 4b together with the carrier gas from the lances 6a to 6C.

Here, into the hot metal 5 flowing in one reaction zone 4a, a powder flux for desilization is injected from the lance 6a, and a powder flux for dephosphorization is injected from the lance 6b, so that the si in the hot metal 5,!
The purpose of treating P at the same time is to allow the powder flux for removing Si, such as mill scale, to undergo the de-S reaction in a highly basic state in which the powder flux for removing P is present. In such a state of high basicity in which the powder flux for desulfurization coexists, the powder flux for desulfurization has high reactivity, so the removal efficiency of Sl increases, and the generated Sj,02
It is also possible to prevent the slag 7a containing iron from turning black due to iron such as mill scale. Furthermore, the coexistence of the powder flux for dephosphorization can prevent slags 7a and 7b from resulfurizing into the hot metal. Further, the basicity (Ca/5i02) of the slag 7a containing S and i02 is usually about 0.1 to 0.5, and the basicity of the slag 7b containing P2O5 is usually 3.0 to 4.0. These slags 7a and 7b have poor fluidity when used alone.
If the slag is mixed, the basicity will be about 1.5 to 2.0 and the fluidity will be improved. Slag 7a
and 7b can be discharged with good flow.

When blowing the powder flux, the bath depth of the hot metal 5 is I (when the penetration depth Hp into the hot metal 5 is 0.50H≦)
It is desirable to control it so that it becomes lp(H).

According to such blowing of powder flux, reaction zone 4
It is possible to prevent wear and tear caused by the collision of powder flux on the bottom surface 1a' (the taphole floor part) of the tap hole 1 in parts a and 4b, and to improve the contact between the powder flux and the hot metal 5. The impurity removal reaction can be carried out in a short time and with high efficiency. The penetration depth Hp of such powder flux
is controlled by the formula derived by the inventors: Hp = Q 6e
xp' (-r) / (Zheng+-o, IHL) 2 (Feed rate of powder Franks in tube 9 CKg/min)
, ('', Carrier gas supply rate [N7++7m1n
), Y: average particle diameter of powder flux Cmm, :],
do, lance inner diameter Ccnr), ■]: lance height from the hot metal surface [α]).

Slags '7a to 7 generated by blowing powder flux are deposited on the side walls of the tap hole 1 in the reaction zones 4a and 4b.
1] and 7C are connected to sump troughs 9a and 9b for discharging and processing the slag separately from the blast furnace slag flowing through the slag trough 2. These troughs 9a and 9h are preferably provided upstream of the tap troughs of the reaction zones 4a and 4b, respectively, as shown in the figure.

By providing the gutter (') a, 9b at the upstream position, the reaction zones 4a, 71. Slag 7a generated in each of b
~7b, slag ゛/C can be flowed toward the flow to create a flow in the opposite direction to the hot metal 5, so the powder flux for dephosphorization and powder flux for dephosphorization blown from lances 8a and 8b. The hot metal 5 can be desiliconized by blowing the powder flux for de-S1 from lance 6a and the powder flux for de-S1 blown from lance 8C. Departing from Lance 6b
The hot metal 5 is dephosphorized by blowing the powder flux for dephosphorization, and the slag 7a containing Sin and the slag '7b containing P2O produced thereby pass through the gutter 9a and are discharged together from the reaction zone 4a. The slag is discharged and stored in a pot 10a located at the discharge end of the gutter 9a. Similarly, the S-containing slag 7C generated in the reaction zone 4b passes through the Yuzu i9b and is stored in the pot 10b.

Therefore, according to this device, from the hot metal 5 discharged from the blast furnace and flowing down the tap hole 1, the blast furnace slag 7' is first separated by the skimmer 3a, and then Sl and P in the hot metal 5 are removed in the reaction zone 4a. At the same time, the slags 7-a and 7b containing 5102 and P2O are separated by the skinmer 3b, and then the S in the hot metal is removed in the reaction zone 4b, and the slag 7C containing S is separated by the skinmer 30. be done. On the other hand, slag 7 containing separated SiO□
The slag 7b containing a and P2O is stored together in the pot 10a through the gutter 9a, and the slag 7c containing S
are stored in the pot 101) through @iHb and processed individually.
Reaction zones 4a and 4b are formed by a to 3C, and reaction zone 4
Sl and P are treated simultaneously in a, and then S is treated in reaction zone 4b.
4'+' is designed to process the reaction zone 4.
Except for processing Sl and r in a, the subsequent processing is in S.
However, the treatment can be carried out by increasing or decreasing the reaction zone depending on the number of impurities to be treated. 7. (1) Powder flux for tapping iron (1) that can remove Sl and 1 from hot metal at a high rate in the iron tapping (1) (2) De-S) and powder flux for de-S (1) Blow into the bath iron in one reaction zone,
Since S, and P are treated simultaneously, the reactivity of the powder Franks for removing Sj can be increased, and the generated Sj, (
') Residual powder flux for de-S1 in slag containing 2 - Since the fan can be made smaller, slag containing SlO□ and 1'
2 (including +5 73・slag) can be combined with 1 slag to turn black with 11 power II'('') S j, (
, )2 and the slag containing F''205 together, the fluidity is improved compared to when these slags are used alone, so that these slags can be smoothly discharged.

(4) S in the slag containing 5in2 and the slag containing P2O does not leave behind in the hot metal6, (5)
Since the blast furnace slag and the slag produced in each reaction zone can be treated separately, the quality of these slags can be improved.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the hot metal processing equipment of the present invention, and FIG. 2 is a plan view showing the AA&! It is an arrow view. In the drawings: 1. Tap trough, la - tap trough bottom, 2. Slag trough, 3.
a-3c skinmer, 4 a-t↓P)-reaction zone, 5. hot metal, 6a-6C... u/s, 'n a-7C, slag, 7', blast furnace slag, 8a-8C, refining agent tank,
9a-9b-gutter, 10a-10b-47,1
1. Gutter cover.

Claims (2)

[Claims] (1) Two skimmers are placed downstream of the slag gutter connection position of the blast furnace tap water, with their lower ends immersed in the hot metal flowing through the tap water with a space between them and the bottom of the tap water. It was partitioned off by the two skimmers by installing the two skimmers with a gap between them. One reaction zone is provided, and in the one reaction zone, a first lance for injecting a powder flux for desalinization into the hot metal at a high speed and a tank for injecting a powder flux for dephosphorization at a high speed. with the second lance,
The tips of the first and second lances are installed away from the surface of the hot metal, and the slag generated in the one reaction zone is disposed of on the side wall of the tap water of the one reaction zone. A hot metal processing apparatus, characterized in that a gutter is connected to treat the blast furnace slag separately from the blast furnace slag flowing through the slag gutter. (2) Claim 1, characterized in that the slag for discharging the slag produced in the one reaction zone is connected to a position upstream of the tap hole of the one reaction zone. Hot metal processing equipment as described in section.