JP4111115B2 - Dob treatment method for non-ferrous smelting furnace - Google Patents

Description

  The present invention relates to a smelting method for obtaining valuable metals such as copper and nickel from sulfide concentrates containing valuable metals such as copper and nickel.

Conventionally, there is a method of using a smelting furnace such as a self-smelting furnace, a converter, and a refining furnace as a method for obtaining a valuable metal from a nonferrous metal raw material such as sulfide concentrate. In this method, for example, copper sulfide concentrate, flux, and the like are blown into a flash furnace together with auxiliary fuel, oxidized and smelted, and the copper content is mainly composed of iron or Cu ₂ S mainly composed of FeS and Cu ₂ S. White sulfur as a component, and sulfur content is recovered as sulfurous acid gas. The obtained river or white river is extracted from a smelting furnace such as a self-melting furnace into a ladle, etc., transported to the converter, and charged into the converter. Then, oxidation smelting is continued in the converter.

The converter process is broadly divided into a canning period in which a flux of silica or the like is charged into the converter, and the Fe content contained in the melt is fixed to the slag, and S in Cu ₂ S is removed. It consists of a copper making stage to obtain crude copper, and each reaction is represented by the following formula.
Canning period 2FeS + 3O ₂ + SiO ₂ → 2FeO · SiO ₂ + 2SO ₂
Copper making stage Cu ₂ S + O ₂ → 2Cu + SO _{2
Cu 2 S + 3 / 2O 2} → Cu 2 O + SO 2
2Cu ₂ O + Cu ₂ S → 6Cu + SO ₂

Both the reaction during the can-making period and the copper-making period are exothermic reactions. If left as it is, the melt temperature becomes too high and the bricks in the furnace are damaged. For this reason, a copper-containing compound such as copper scrap, late copper, copper slag, and smoke ash is added as a cooling agent, so that excessive reaction heat is absorbed in the melting and the like, and the melt temperature is maintained within a certain range.

Crude copper obtained after completion of the copper making period is charged into a refining furnace. In the refining furnace, impurities in the crude copper are separated and removed on the surface of the crude copper as a refining furnace slag by a reaction gas or the like blown from a tuyere provided near the middle part of the furnace body. The refined crude copper from which impurities are removed is discharged out of the furnace, sent to a casting process, and cast on a refined anode.

By the way, when the crude copper is transferred from the converter to the refining furnace, a part of the FeO—Cu ₂ O—SiO ₂ slag remaining in the converter is mixed into the crude copper and brought into the refining furnace. For convenience, this slag is referred to as a dove. This dove has a magnetite quality of 40% or more.

The dove brought into the refining furnace floats on the surface of the molten crude copper due to the difference in specific gravity. Therefore, the refining furnace is tilted and discharged from the furnace opening to the ladle. The dove discharged to the ladle is usually charged and processed in the converter during the copper making phase of the converter in the molten state in order to recover the copper component accompanying the dove. At this time, when a large amount of dove is returned to the converter, the dove remains in the converter even after the converter copper making period, and this is the flux charged during the next converter canning operation. It reacts to form FeO-SiO ₂ slag.

Therefore, if the amount of dove charged into the converter as a repetitive product in the converter copper making phase is larger than the expected amount, the amount of dove remaining in the furnace after the copper making phase ends will exceed the expected amount. It is unavoidable to add an appropriate amount of flux during the building process. The amount of heat commensurate with the melting of the additional charge of the flux is consumed, causing heat shortage during the canning period in the converter, resulting in poor reactivity during the converter canning period, and worsening the slag properties. As a result, it becomes difficult to discharge the slag from the converter furnace port, which causes a problem that hinders the converter operation.

Such a problem does not become a big problem if the amount of dough discharged from the refining furnace is stable. However, as a result of adopting an operation of charging dough into the converter in the total copper making stage, the amount of dobbing generated in the refining furnace fluctuates as large as 5 to 15 t / times, so that the above problem becomes serious.
This invention is made | formed in view of such a conventional problem, and it aims at provision of the nonferrous metal refining method which can prevent the deterioration of the slag property in a converter canning stage.

The present invention that achieves the above object is a method of performing nonferrous metal refining using a smelting furnace, a converter, and a refining furnace, and when collecting copper in a dove discharged from the refining furnace, Transfer the entire amount of discharged dob to a mold and cool and solidify it, and / or let it cool in the ladle and solidify it, and then repeatedly charge a portion of the solidified dove into a copper-making converter In addition , the remaining portion is repeatedly charged into the auto-melting furnace as a lump or powder .

In the present invention, the amount of dove repeatedly charged into the converter at the copper making stage is set within a range in which the heat balance in the canning stage of the converter can be taken. This amount is greatly influenced by the composition of the river and white river supplied into the converter, the amount of the cooling agent used, and the like, but cannot be uniquely limited. For example, the converter charge quality is Cu 60 to 65%. When the charging amount is about 225 to 235 t / times , the amount of dove repeatedly charged is 5 to 7 t.

According to the present invention, a large amount of dough is not repeated at the time of the converter copper making period, and deterioration of the slag properties during the converter canning period can be prevented. As a result, the amount of dough generated in the refining furnace was reduced and stabilized.

  In the present invention, the dough is solidified and then repeated in the auto-smelting furnace because it is difficult to reduce the charging amount per unit time if it is repeated in the molten state. This is because if the amount charged per unit time is large, the magnetite quality in the dove is as high as 40% or more, which promotes magnetite troubles in the self-melting furnace. That is, it is necessary to prevent the occurrence of magnetite trouble by operating while reducing and decomposing the magnetite contained in the dove by reducing the charging amount per unit time. In addition, magnetite adheres to a furnace bottom and a furnace wall, and reduces an effective furnace internal volume.

In the present invention, the entire amount of dove discharged from the refining furnace is solidified and pulverized, and charged into the converter and the self-melting furnace in the copper making stage. By doing so, the amount charged into the converter can be stabilized.

In the present invention, the most preferred method, the bleed amount charged repeatedly converter of forming copper life in the range of uninterrupted operation in the converter keep constant, repeated bleeds amount exceeding this self Yoro It is to be charged . If the amount of generated dough is less than the predetermined amount, there is a high possibility that excess heat will be generated in the can-making stage. In such a case, if you add a cooling agent such as copper scrap, late copper, copper slag, and absorb the excess heat Well, there are no particular problems.

Of course, it is possible to keep the dove charged in the converter as a melt, solidify the remainder and repeat it in the self-melting furnace, but in this case, the charging to the converter compared to the method of the present invention is possible. There is a problem that it is difficult to stabilize the amount.

In addition, as a shape at the time of repeating the solidified dough, it is preferable on handling that it is a lump when charging into a converter, and is lump or powder when charging into a self-melting furnace.

In the present invention, since the dove to be charged is a lump or powder, it is easy to handle and the charge amount is easily controlled. Therefore, it is also possible to charge the maximum amount into the converter within a range where the heat balance can be taken, and to charge the remaining portion into the flash furnace. If it carries out like this, it will become possible to reduce the copper loss and cost increase by repetition as much as possible.

As a means for solidifying the dove, for example, there is a method in which a part of the molten dove discharged from the furnace port of the refining furnace to a ladle is transferred to a mold formed of iron called a boat type and cooled and solidified. is there. The dove remaining in the ladle is taken out of the radle after being allowed to cool and solidify.

Using the converter and the refining furnace shown in FIG. 2 and FIG. 3, an operation test was conducted in which 99.5% grade of crude copper of 450 to 500 t was charged into the refining furnace and processed . The bleed that is discharged from the refining furnace to solidify transferred to boat-shown in FIG. 3, was charged repeat 2~3t content in its own Yoro, was charged repeatedly converter of forming copper-life balance.

When this operation was repeated 10 times, the variation in the amount of dough discharged in the refining furnace was reduced to 4-8 t / times from the conventional 5-15 t / times, and the frequency of deterioration of slag properties during the converter canning stage was also reduced. Reduced.

It is the schematic which uses the boat type | mold for cooling and solidifying a dove. It is sectional drawing which shows the outline of the nonferrous smelting converter. It is sectional drawing which shows the outline of the refinement furnace for nonferrous smelting.

Explanation of symbols

1 Converter Furnace 2 Refining Furnace Furnace 3 Feather 4 Tap

Claims (2)

In the method of non-ferrous metal refining using a smelting furnace, converter and refining furnace, when collecting copper in the dove discharged from the refining furnace, the total amount of dob discharged from the refining furnace to the ladle is used as a mold. After transferring and solidifying by cooling and / or allowing to cool and solidify in the ladle, a part of the solidified dough is repeatedly charged into a copper-making converter as a lump , and the remainder as lump or powder A non-ferrous metal refining method characterized by repeatedly charging into a flash furnace. The nonferrous metal refining method according to claim 1, wherein the amount of dove repeatedly charged into the converter at the copper making stage is within a range in which the heat balance in the canning stage of the converter can be taken.

Images