JPH11350050A - Operation of copper smelting and refining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a refined crude copper suitable to electrolytic refining without the need for oxidizing process in a refining furnace, additional processes, lowering the crude copper temp. and extending the time for reducing process. SOLUTION: In a copper smelting and refining, in which copper concentrate consisting essentially sulfide is smelted and removed with a smelting furnace, converter and refining furnace to make refined crude copper suitable to the copper electrolytic refining, sulfur content in the crude copper produced from the converter, is controlled in the range of 0.015-0.050%. This crude copper is charged into the refining furnace and immediately, only reducing process for blowing reducing agent of gaseous ammonia, etc., is executed. In this reducing process, gaseous oxygen in the crude copper is reduced and removed and at the same time, the sulfur is oxidized and removed to obtain the refined crude copper having <=0.005% sulfur content.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a smelting furnace for copper concentrate,
The present invention relates to a copper smelting operation method in which smelting is performed using a converter and a refining furnace to obtain purified blister copper suitable for electrolytic copper refining.

[0002]

2. Description of the Related Art Usually, in copper smelting from copper concentrate, which is mainly composed of sulfide, to refined crude copper suitable for electrolytic copper refining, copper concentrate is first oxidized and dissolved in a smelting furnace. ,copper,
It is divided into rivers mainly composed of iron and sulfur, and karami mainly composed of iron and silica. Kawa generated in the smelting furnace is extracted from the smelting furnace and charged into the converter.

In the converter, air for reaction or oxygen-enriched air for reaction is blown from a tuyere, and further, a flux is charged, and a mixture mainly composed of Fe ₂ SiO ₄ from FeS in a stream and SO ₂ gas Is generated. This process is called the kang-making period, and the generated lumps are discharged outside the furnace. Subsequently, the reaction air or the oxygen-enriched air for the reaction is blown again from the tuyere, and the blister copper and SO having a copper grade of 98% or more are concentrated.
_Two gases are generated, and this process is called the copper making stage.

[0004] The blister copper produced in this converter usually contains 0.02 to 0.5% of sulfur, and is not suitable for electrolytic copper refining in this state. That is, when casting as an anode for electrolytic refining, inconveniences such as deterioration of the shape such as swelling of the anode surface due to SO ₂ gas and passivation of the anode and increase in the amount of slime occur in the next electrolytic refining process. is there. For this reason, blister copper produced in the converter is charged into a refining furnace, and sulfur is oxidized and removed to 0.005% or less.

[0005] In this refining furnace, first, air or industrial oxygen is blown into blister copper in an oxidation step to oxidize sulfur and remove it as SO ₂ gas. However, oxidation of copper progresses as sulfur decreases in the oxidation step, and blister copper originally contains about 0.5 to 1.0% of oxygen. Therefore, following this oxidation step, a reducing agent such as a hydrocarbon gas, an ammonia gas, or heavy oil is blown into the blister copper to reduce oxygen to 0.1.
A reduction step of deoxidizing to about 1 to 0.15% is performed to produce purified crude copper having a sulfur grade of 0.005% or less and suitable for electrolytic purification.

[0006]

In the operation of a refining furnace in ordinary copper smelting, an oxidation step for removing sulfur is required together with a reduction step. However, the reduction step requires about 8
It takes about 0 to 180 minutes, and the oxidation step is usually 30 to
Since it takes about 180 minutes, the operation schedule of the refining furnace is often pressed by this oxidation step. Further, performing the oxidation step has a major drawback in that the blister copper temperature is lowered due to the heat carried away by the exhaust gas, and the subsequent anode casting is likely to be hindered.

[0007] Therefore, it has been considered to omit the oxidation step in the refining furnace. For example, a method has been proposed in which the oxidation step is omitted by blowing nitrogen gas into blister copper.
However, in this method, even if the oxidation step can be omitted, only the step of blowing nitrogen gas instead increases, and the blister temperature also decreases due to the heat carried away by the nitrogen gas. Absent.

[0008] The operation method of the converter particularly includes As, S
In the case of a raw material having a high impurity grade such as b, Pb, Zn, etc., there is a method of blowing more (referred to as overblow) than in the case of obtaining normal blister copper in a converter for the purpose of removing these impurities by oxidation. In this case, as a result, the sulfur grade in the blister copper is reduced to about 0.01%. Therefore, in such a case, as a result, the oxidation step in the refining furnace can be omitted, but it is a peculiar method performed only in a special raw material situation.

In addition, in the case of such an overblowing operation, the oxygen grade in the blister copper is inevitably increased to 1 to 2%, so that the time required for the reduction step for removing oxygen in the refining furnace is greatly increased. There is a drawback that the efficiency is extremely reduced as compared with the operation of a refining furnace that performs a normal oxidation step. In addition, part of the copper is oxidized to copper oxide by overblowing, and karami having a low melting point with Fe ₂ O ₃ and SiO ₂ is generated. When the raw material is charged, the raw material reacts with the raw material to generate a large amount of fumes such as SO ₂ gas and Pd, thereby causing a problem of remarkably deteriorating the environment.

The present invention has been made in view of such a conventional situation,
It is possible to obtain purified blister copper suitable for electrolytic refining without omitting the oxidation step in the refining furnace and without increasing the number of extra steps, lowering the blister temperature and extending the time required for the reduction step. It is an object of the present invention to provide a method of operating copper smelting that can be performed.

[0011]

In order to achieve the above object, a method for operating copper smelting provided by the present invention comprises a smelting furnace, a converter, and a refining process using copper concentrate mainly composed of sulfide. In copper smelting, which is refined in a furnace to obtain purified blister copper suitable for copper electrolytic refining, the sulfur grade in the blister copper produced from the converter is reduced to 0.
After the blister copper is charged into a refining furnace, the oxidation step is omitted, and only the reduction step of removing oxygen in the blister copper by blowing a reducing agent is performed.
It is characterized by obtaining purified crude copper having a sulfur grade of 0.005% or less.

In the actual operation, when the sulfur content in the blister copper in the converter has fallen to the range of 0.015 to 0.050%, blowing of the converter is terminated, and the blister copper is removed from the converter to the refining furnace. Immediately after that, a reducing agent such as a hydrocarbon gas or an ammonia gas is blown into the blister copper to obtain an oxygen grade of 0.1 to 0.1.
Reduce and remove dissolved oxygen until it becomes about 15%. The purified crude copper obtained in the refining furnace has a sulfur grade of 0.005% or less, and is then cast into an anode and subjected to an electrolytic refining process.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, conventionally, when the sulfur grade in blister copper produced from a converter is higher than 0.005% of the sulfur grade in a target anode for electrolysis,
In order to remove sulfur until the sulfur grade is reached, it is considered necessary to perform an oxidation step in which air or industrial oxygen is blown into the blister copper in the refining furnace. The process was being implemented.

In contrast to the prior art, the present invention eliminates the oxidation step in the refining furnace and reduces and removes the oxygen in the blister copper only by the reduction step in which a reducing agent is blown. It is removed to a sulfur grade suitable for purification. That is, the sulfur grade in the blister copper from the converter was set to 0.
If it is controlled to 050% or less, the blister copper is agitated by blowing a reducing gas in a refining furnace, and oxidation of sulfur proceeds by oxygen dissolved in the blister copper or oxygen entrained from the atmosphere, and only the reduction step is performed. Can remove sulfur to 0.005% or less of sulfur grade.

Further, according to the present invention, it is not necessary to add a special step instead of omitting the oxidation step in the refining furnace, and it can be replaced by only the reduction step conventionally performed. In addition, the time required for the reduction step in this refining furnace does not generally exceed the time required for the reduction step after performing the conventional oxidation step, and even if the sulfur quality in the blister copper is relatively low, Is shorter than the total time of the oxidation step and the reduction step. The blister temperature in the refining furnace is higher than in the case of performing the oxidation step and the reduction step, which is convenient for casting the anode for electrolytic refining later.

However, if the sulfur grade in the blister copper produced from the converter exceeds 0.050%, the sulfur grade in the blister copper is too high.
% Cannot be removed, and an oxidation step is required as usual. Conversely, the sulfur grade in blister copper is 0.015
%, The oxidation step can be omitted, but the oxygen level in the blister copper becomes too high due to overblowing in the converter, so the reduction time in the refining furnace is greatly lengthened, and the efficiency of the refining furnace is significantly reduced. I do.

[0017]

EXAMPLE By changing the operating conditions in the converter, the sulfur grade of the blister copper produced from the converter was changed as shown in Table 1 below. The blister copper in each case was transferred from the converter to the refining furnace, and 500 tons were charged into each of the refining furnaces until the refining furnaces were filled while keeping the heat with a heavy oil combustion heat retention burner.

Thereafter, in case 3, 12 tuyeres are
Although the reduction step was performed following the oxidation step of blowing air of 00 Nm ³ / H, in other cases, the same two blades were immediately supplied with 800 to 1000 kg / hour of a reducing agent (propane gas) without passing through the oxidation step. The reduction step was performed by blowing through the mouth. Table 1 shows the sulfur grade and temperature of purified crude copper (oxygen grade 0.1 to 0.15%) obtained in the refinery furnace for each case.
Are also shown.

[0019]

[Table 1] Converter grade crude copper reducing agent refined crude copper case Sulfur grade temperature Oxidation process Reduction process blowing quantity Sulfur grade temperature 1 0.02% 1130 ℃ None 2.1hr 1500kg 0.001% 1180 ℃ 2 0.03% 1130 ℃ None 1.6hr 1400kg 0.002 % 1175 ℃ 3 * 0.03% 1130 ℃ 0.5hr 1.7hr 1550kg 0.002% 1165 ℃ 4 0.05% 1135 ℃ None 1.4hr 1300kg 0.005% 1170 ℃ 5 * 0.10% 1140 ℃ None 1.3hr 1200kg 0.015% 1170 ℃ (Note) Cases marked with * are comparative examples.

As can be seen from this result, if the sulfur grade in the blister copper obtained in the converter is controlled to 0.05% or less, the purified bleached copper can be reduced only by the reduction step without performing the oxidation step in the purification furnace. Can be reduced to 0.005% or less, and the sulfur grade in the purified blister copper does not largely depend on the sulfur grade in the blister copper. However, if the sulfur grade in the blister copper in the converter is reduced to less than 0.015% due to overblowing, the reduction time required to obtain the purified blister copper having the desired oxygen grade in the refining furnace becomes extremely long, which is extremely improper. Economy.

In case 3, the oxidation was performed for 0.5 hours prior to the reduction step. However, the sulfur grade in the purified crude copper obtained was the same as in case 2 without the oxidation step. , And the amount of propane gas used as a reducing agent increases. In Case 5, the sulfur grade in the blister copper obtained in the converter was 0.05%
Therefore, the sulfur quality could not be reduced to 0.005% or less only by the reduction step in the refining furnace, the surface of the anode was swollen in the subsequent casting step, and the casting step could not be continued. .

[0022]

According to the present invention, it is possible to produce purified crude copper suitable for electrolytic refining after the sulfur grade is 0.005% or less by omitting the oxidation step in the refining furnace and only the reduction step. . Moreover, in the operation of the refining furnace, no extra steps are required, the temperature of the blister copper is not reduced, and the time required for the reduction step is not prolonged, so that the copper smelting can be performed very efficiently.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masato Murakami 3-5-3 Nishiharacho, Niihama-shi, Ehime Pref.

Claims (1)

[Claims] Claims 1. A copper concentrate mainly composed of sulfide is used as a raw material.
In copper smelting, which is refined in a smelting furnace, a converter, and a refining furnace to obtain purified blister copper suitable for copper electrolytic refining, the sulfur grade in the blister copper produced from the converter is 0.015 to 0.050%. After the blister copper is charged into the refining furnace, the oxidation step is omitted, and only the reduction step of removing oxygen in the blister copper by blowing a reducing agent is performed, and the sulfur grade is 0.005% or less. A method for operating copper smelting, characterized by obtaining purified crude copper.