JPS59222552A - Manufacture of manganese-base ferroalloy - Google Patents

Abstract

PURPOSE:To accelerate a reaction and to manufacture an Mn-base ferroalloy in a short time by charging molten slag contg. Mn and a ferroalloy contg. Si into a reactor and by blowing an agitating gas from a nozzle at a high rate to cause a reducing reaction. CONSTITUTION:Molten slag contg. Mn produced as a by-product in the manufacture of ferromanganese is charged into a reactor, and a ferroalloy contg. Si is charged in a molten state. An agitating gas such as Ar, other inert gas or nitrogen is blown from a nozzle placed in the reactor at >=300Nm/sec and >=0.2Nl/ min.kg rate to force the charged slag and ferroalloy to be agitated. Thus, a reducing reaction attains a nearly equilibrium state in a short time without using any special heating means. By this method an Mn-base ferroalloy contg. Si is obtd. by short-time refining, and the recovery rate of Mn in the slag is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a ferro-alloy based on manganese by a reduction reaction between a molten slag containing manganese and a ferro-alloy containing silicon. The present invention proposes a method for producing a manganese-based ferroalloy having a silicon content of 0.1 to 30% by recovering manganese as ferromanganese, ferromanganese, or the like.

High-carbon ferromanganese is produced by heating and melting manganese ore and coke in an electric furnace, reducing the manganese ore with coke, and adding iron ore to adjust the iron content. . By the way, in general,
In the slag produced during the production of ferromanganese, manganese is discharged at a high concentration of about 20 to 300% by weight. Therefore, from this molten slag, mutton cancer (Mn), ferromanganese, or silicomanganese
Various methods have been proposed for producing Mn-based ferroalloys that are recovered as ferrous metals.

All of these production methods involve reducing manganese oxide (mainly Mn0) with a silicon reducing agent. In addition, it is based on the so-called thermite reaction method in which the reaction proceeds using the heat generated by this reduction reaction. However, in these known techniques, the reaction does not proceed sufficiently, and a high concentration of Mn remains in the molten slag after the reaction.

For this reason, the recovery efficiency of Mn from molten slag is low, and Mn
n remains in the slag at a high concentration and is wasted.

For example, in Japanese Patent Publication No. 44-22734, in Example 5, Mn was 9.0% in the molten slag after the reaction.
% (11.6 cm as MnO) remains.

According to the research results of the present inventors, when the reaction reaches equilibrium, the basicity of the slag after the reaction [(1,39XMgO
There is an extremely strong correlation between the Mn concentration in the slag after the reaction and the silicon (St ) concentration in the ferromanganese after the reaction. It is clear that According to this, when the slag basicity after the reaction is 0.79 as in Example 5, the Mn concentration (wt%) Y in the slag after the reaction and the St concentration (wt% ) The following (
The formula 1 holds true.

Y knee 0.87x + 22.3 ・・・・・・・・・
(1) In the embodiment of Example 5, X is 2
Since it is 3.7%, according to equation (1), the equilibrium Mn concentration Y
is found to be 1.7chi. However, after the actual reaction, Kura 5
Since the Mn concentration in the sample was 9.0%, it can be seen that the reaction did not proceed sufficiently.

In addition, in Japanese Patent Publication No. 10773/1984, the slag basicity after reaction was 0.88, and the Mn concentration in the slag was 17.
2%, and the 81 concentration in ferromanganese is 11.2%. According to the research results of the inventors, when the slag basicity is 0.88, when the reaction reaches equilibrium, Y and
The following equation (2) holds true between .

Y,=-0,87X+18.5 ・・・・・・・・・
(2) According to equation (2), when the reaction progresses to a state close to equilibrium, the Mn concentration in the slag should decrease to 8.8%. However, since the actual Mn concentration in the slag after the reaction is 17.2, it can be seen that the reaction has not progressed sufficiently in this case as well.

Moreover, in this technology, as described in the detailed description of the invention section of the specification, Mn is used as a starting material.
Since it is necessary to use a molten slag containing 5- or more, Mn cannot be recovered from the molten slag (Mn concentration 17.2%) after the above reaction using this technique. Therefore, even though it contains a high concentration of Mn, the slag after the reaction has no choice but to be discarded.

Furthermore, in Japanese Patent Publication No. 53-37812, molten slag and a molten image s whose St concentration was adjusted in advance to 1 to 5
Although the i-concentration iron alloy is used, the stirring time is as long as 15 minutes.

Furthermore, in Japanese Patent Publication No. 57-36337, since it is necessary to cause the reaction vessel to perform horizontal eccentric movement, the amount of charge is limited because the charge moves in a wave-like manner. Further, in Examples 1 and 2 described in the specification, the stirring time was 18 to 2.
The stirring time is as long as 3 minutes, and even when the SI-containing iron alloy and flux are heated and melted in advance (Example 3), stirring for 9 minutes is necessary.

This invention was made in view of the above circumstances, and aims to improve the Mn recovery efficiency and shorten the refining time by powerfully stirring the Mn-containing molten slag and the St-containing ferroalloy. The purpose of the present invention is to provide a method for manufacturing a manganese-based ferroalloy. That is, in all conventional methods for producing Mn-based ferroalloys by recovering Mn from molten slag by out-of-furnace refining, the stirring force of the charge is light.

As a result of repeated research, the inventors of the present application have found that by increasing the stirring power of the charge, the reduction reaction can proceed to a near-equilibrium state in an extremely short time and without the need for special heating means. It has been found that Mn can be recovered with high efficiency. The present invention was made from this point of view, and in order to strongly stir the charged material, stirring gas is discharged at high speed from a nozzle provided in the charged material.

The method for producing a manganese-based ferroalloy according to the present invention includes charging a ferroalloy containing molten slag containing manganese into a reaction vessel, and using a nozzle installed in the charged material for stirring. More than 30ONV seconds of gas and/or 1kl charge! The molten slag containing manganese and the ferroalloy containing weakly contained manganese are reduced and reacted by discharging the slag into the charge at a rate of 0.2 Nly or more and stirring the charge to produce a ferroalloy containing manganese. It is characterized by

The present invention will be explained in detail below. Manganese-based ferroalloy (
Mn-containing molten slag, which is a raw material for producing ferromanganese (ferromanganese, silicomanganese, etc.), is high carbon ferromanganese, medium carbon ferromanganese.

When producing low carbon ferromanganese or Sbeegel,
Molten slag produced as a by-product in an electric furnace or the like can be used. This molten slag is charged into a reaction vessel lined with a refractory material, such as a ladle. The temperature of the molten slag during charging is preferably 1300°C or higher.

Si-containing ferroalloy is charged into a reaction vessel containing this molten slag. As the Si-containing iron alloy, metal silicon,
Ferrosilicon, silicomanganese or calcium silicon can be used. In terms of reaction efficiency, it is preferable to charge the weak Si-containing iron alloy into the reaction vessel in a molten state. However, even when the Si-containing ferroalloy is charged into the reaction vessel in a solid state at room temperature without preheating, the object of the present invention can be fully achieved.

In addition, Mn-containing molten slag and Si-containing ferroalloy are
It can be loaded up to about 80 inches of the transponder's capacity.

A stirring gas is blown into the charge in the reaction vessel through a nozzle installed in the charge to stir the charge. As the stirring gas, an inert gas such as argon gas or nitrogen gas can be used. Further, in order to raise the temperature of the charged material while stirring, oxygen gas may be used in combination. In order to discharge the stirring gas into the charge, a lance whose tip nozzle part is immersed in the charge and the surrounding area is covered with refractory material may be used, or a lance whose tip nozzle part It is also possible to use a gas supply pipe which is inserted through the bottom wall of the reaction vessel and faces into the charge. The discharge direction of the stirring gas is preferably set so as to maximize the stirring effect on the charge. −
For example, it is possible to discharge horizontally from 2 to 4 locations near the center of the bottom of the reaction vessel.

In this invention, pressurized gas is discharged into the charge at high speed from a nozzle installed in the charge, and the charge is strongly stirred by the powerful discharge energy.
The reduction reaction can be achieved in a near-equilibrium state in an extremely short time without providing any special heating means. Therefore, in order to achieve the object of the present invention, the discharge energy of the stirring gas is an important factor. Even if the amount of stirring gas is the same, this discharge energy varies depending on the shape of the reaction vessel, the amount of charge, specific gravity, temperature, viscosity, etc. Therefore, the inventors of the present invention conducted experiments while variously changing these refining conditions, and determined the relationship between the discharge energy and the Mn recovery efficiency or the time until the reaction ends in a state close to equilibrium. In this case, the amount of discharge energy is determined by the pressure P of the stirring gas when blown into the charge (secondary gas pressure), the standard of the stirring gas when blown into the charge. It was quantified by the flow rate converted to the state (0° C., 1 atm) or the flow rate converted to the standard state of the stirring gas per 1 kg of the charge (molten slag and ferroalloy). As a result, it was found that the reduction reaction was completed in an extremely short time when the flow rate V was 30ONtnβ or more or the flow rate was 50.2NlZ or more per weight of charge.

Note that the secondary gas pressure P varies depending on the depth of immersion of the nozzle in the charge, but is preferably about 4 kg/crn2 or more. By stirring the charge under such discharge conditions, the Si-containing ferroalloy in the reaction vessel is dispersed and suspended in the molten slag at a relative speed to the molten slag, and is rapidly reduced (reduced). The reaction progresses.

The reaction between Mn oxide (mainly Mn0)' and St is an exothermic reaction. The reaction proceeds without heating, ie, without external heat supplementation. However, as in the case where the temperature of the molten slag at the start of the reaction is low, there are cases where the required temperature cannot be maintained only with the amount of heat generated during the reaction. In this case, oxygen gas or a heating gas containing oxygen gas such as air may be blown into the charge. In this case, in addition to the amount of Si-containing ferroalloy necessary to obtain the composition of the R1n-based ferroalloy to be manufactured, an amount of Si necessary to raise the temperature of the charge by reaction with oxygen gas is added. A containing ferroalloy is added, or an oxidizing exothermic substance containing one or more types of Sl*aluminum (CAL) or carbon (C) is charged into the reaction vessel as an exothermic agent. Then, oxygen-containing gas (heating gas) is blown into the charge using a nozzle such as an immersion lance, and the heat generated by the reaction between the exothermic agent and the oxygen gas raises the temperature of the charge to the required temperature. . A stirring gas is then introduced into the charge, as described above, via a separate nozzle or by sharing the nozzle for the introduction of the oxygen-containing gas, and the charge is stirred. Note that the temperature increase using the oxygen-containing gas and the stirring using the stirring gas may be performed in parallel.

In order to adjust the basicity of the molten slag or to improve its fluidity, flux may be introduced into the charge at appropriate times during and/or prior to the introduction period of the stirring gas. Can be injected via carrier gas. Such a flux is quicklime 1 limestone.

Dolomite, fluorite, calcium chloride or salt, etc.
This flux can be added to the charge in the solid state at room temperature. For example, when increasing the basicity of the charge in order to adjust the composition of the ferromanganese to be produced, a basic slack such as quicklime 9 limestone or dolomite may be used.

Preferably, the flux is blown into the charge via a carrier gas through a nozzle provided in the charge. Even if slack with a low specific gravity is dropped onto the surface of molten slag, the flux will float on the slag surface and solidify, and will not be dispersed in the slag, so the effect of modifying the slag will be small. As the carrier gas, nitrogen gas, argon gas/carbon dioxide gas, carbon oxide gas, oxygen gas, air, or a mixture of two or more thereof can be used. Note that when the viscosity of the molten slag is extremely high, it is necessary to reduce the solid-gas ratio [(weight of powder blown in per unit time)/(weight of carrier gas blown in per unit time)].

Further, it is preferable to increase the discharge energy of the stirring gas to achieve even stronger stirring. It is preferable for the particle size of the flux to be re-entrantly small due to the need for rapid dispersion and rapid reaction, as well as constraints from the construction of the blowing device.
Practically speaking, it is sufficient to have 10 ports or less.

As mentioned above, when adding 7lux to improve the basicity or fluidity of molten slag, the amount of flux used is small, so there is no need to provide special heating means to turn the flux into slag. do not have. On the other hand, even when producing ferromanganese with an extremely low Sl content, flux may be added to the charge during refining. In this case, since it is necessary to continuously add a large amount of 7 lux, a heat source for turning the flux into slag is insufficient, so it is necessary to raise the temperature of the charged material. Therefore, as mentioned above, S
A temperature raising treatment is performed by a reaction between the i-containing iron alloy or the exothermic agent and the oxygen-containing gas.

The Mn-based ferroalloy refined as described above is cast after removing the molten slag after the reaction.

Since this reaction progresses to a state close to equilibrium, the degree of Mn IJ in the slag after the reaction is extremely low.

Next, embodiments of the invention will be described.

[Example 1] Molten slag as a charging raw material was a by-product during the production of high carbon ferromanganese, and was directly charged into a reaction vessel from the electric furnace. The composition of this molten slag and Si-containing iron alloy,
Basicity 9 The charging amount and charging temperature are as described in the Example 1 column of Table 1. This molten slag has an inner diameter of 10fIn.
A lance having two gas discharge nozzles of φ was immersed, and stirring gas was discharged at high speed in two horizontal directions while adding Si-containing iron alloy whose particle size was adjusted to 10 mm or less.

The stirring conditions are as described in the Example 1 column of Table 2. Note that the discharge flow rate (N743 tank) is the flow rate of the stirring gas discharged from the lance into the charge under standard conditions. After stirring for 5 minutes, the lance was pulled out and the generated slag was removed, and the obtained Mn-based ferroalloy was cast. Its composition, amount, etc. are as described in the Example 1 column of Table 4.

In this way, a Mn-based ferroalloy is produced in an extremely short time, the Mrr remaining in the slag is extremely small at 6.4% by weight, and the Mn recovery efficiency is extremely high.

In this example, flux (quicklime and fluorite) was added to improve the basicity and fluidity of the slag. The composition and charging amount of the molten slag are as shown in Table 1. A stirring lance having two nozzles with an inner diameter of 5 mm was used. The discharge direction is sb in two horizontal directions.
The stirring conditions were as shown in Table 2. Simultaneously with the start of stirring, powdered Si-containing ferroalloy, quicklime, and fluorite having the compositions shown in Table 1 were blown into the molten slag via a carrier gas. The conditions for blowing the carrier gas were as shown in Table 2, and an immersion lance with an inner diameter of 36 wφ was used. This blowing time is 3 minutes. The grain size of the Si-containing ferroalloy was 3 mm or less, the total amount of carrier gas used was 11N3, and the solid-gas ratio was 92.

After blowing in the carrier gas, the lance was pulled up, and blowing of the stirring gas from the stirring lance was continued for another 2 minutes. Therefore, the total stirring time is 5 minutes as listed in Table 2. The composition and amount of the product after stirring are as shown in Table 4. After lifting the stirring lance,
Mn-based alloy iron was cast. In this example as well, the Mn concentration in the slag after the reaction was reduced to 6.8% after stirring for 5 minutes, indicating extremely high recovery efficiency.

[Example 3] In this example, oxygen gas was introduced to raise the temperature of the charge. Table 1 shows the temperature at the time of charging the slag and molten slag.
As described in (1280°C, which was as low as 1280°C.) Therefore, after charging the molten slag into the reaction vessel, the Si-containing ferroalloy listed in Table 1 was charged onto the slag, and the cross-sectional area of the outer tube was 0.126 cm2.
A lance having a nozzle having a double tube structure with an inner tube cross-sectional area of 0.478 cm2 was immersed. 02 gas from the inner tube and N2 gas from the outer tube were blown into the molten slag under the conditions shown in Table 3. The N2 gas blown from the outer tube is used to prevent the nozzle from melting due to the introduction of the 02 gas, and has the function of cooling the nozzle tip.

After blowing in these 02 gas and N2 gas for 2 minutes, the gas flowing through the inner tube was switched from 0□ gas to N2 gas, and N2 gas was introduced into the charge from the inner tube and outer tube. Stirred.

The stirring conditions are shown in Table 2. After stirring for 4 minutes, the temperature of the melt began to decrease and the reaction was complete. As shown in Table 4, Mn is 1.6 in the slag after the reaction.
Only % by weight remains.

[Example 4] In this example, Heflux was added to the charge and the temperature drop of the charge was prevented by introducing 02 gas. Molten slag having the composition shown in Table 1 was directly charged into a reaction vessel from a high carbon ferromanganese production furnace. Next, the inner diameter is 5.
A stirring lance with two nozzles each having a diameter of 7 m was immersed in the molten slag. As shown in Table 2, a mixed gas of 02 gas and Ar gas is introduced into the charge from this lance and stirred, and the heat of reaction caused by the 0□ gas prevents the temperature of the charge from decreasing. The temperature was kept constant. At the same time as this stirring, the Sl-containing iron alloy (
(g) and (B) were charged onto the molten slag. In addition, in parallel with this stirring, quicklime and common salt having the composition shown in Table 1 were added.
N2 gas was blown as a carrier gas under the blowing conditions shown in Table 2.

For this slack blowing, a blowing lance with an inner diameter of 17 mm was immersed into the charge. After injecting the flux for 7 minutes, only the blowing lance was pulled up, and the introduction of 02+Ar gas from the lance accompanying the blowing was continued for about 1 minute. Therefore, the stirring time is approximately 8 minutes. In addition, only 4.8 Nm3 of carrier gas was used, and the flux had a particle size of 1.
I used something below the diameter. As for the Jjt stirring gas, 34 Nm' of 02 gas and 8 Nm of Ar gas were used. The composition of the low St ferromanganese thus produced is shown in Table 4, and the degree of Mn remaining in the slag after the reaction is extremely low at 2.2 weight.

°' As explained above in detail, according to the present invention, the reaction proceeds rapidly, so that a manganese-based ferroalloy can be produced in an extremely short time.

Further, since the reaction reaches a state close to equilibrium by strong stirring, the amount of M and n remaining in the slag after the reaction is extremely small, and Mn can be recovered with high efficiency. Therefore,
This invention is extremely beneficial in the production of manganese-based ferroalloys.

Claims (5)

[Claims] (1) Molten slag containing manganese and ferroalloy containing silicon are charged into a reaction vessel, and a stirring gas of 30 ONd or more is supplied from a nozzle installed in the charge and/or the charge 1 The molten slag containing manganese is discharged into the charge at a rate of 0.2Nl/9 or higher, the charge is stirred, and the manganese-containing molten slag and the silicon-containing ferroalloy are subjected to a reduction reaction to produce a manganese-containing ferroalloy. A method for producing a manganese-based ferroalloy. (2) During an appropriate period during which the stirring gas is being introduced into the charge and/or during a period prior to the introduction, the particle size is The method for producing a manganese-based ferroalloy according to claim 1, characterized in that 7 lux, which is 10 fields or less, is blown into the charge together with a carrier gas. (3) During an appropriate period during and/or a period prior to the introduction of the stirring gas into the charge, a heating gas containing oxygen gas is blown into the charge. 3. The method for producing a manganese-based ferroalloy according to claim 1 or 2, which comprises raising the temperature of the container to a predetermined temperature. (4) The method for producing a manganese-based ferroalloy according to any one of claims 1 to 3, wherein the stirring gas is an inert gas or nitrogen gas. (5) The method for producing a manganese-based ferroalloy according to any one of claims 1 to 4, characterized in that the stirring gas is introduced for 10 minutes or less.