JPH07258761A - Operation method of copper smelting converter - Google Patents

Abstract

PURPOSE:To compensate the deficiency of heat in a converter and to intensify the treating capacity of copper matte by this converter by blowing solid carbon fuel into the converter at the time of obtaining blister copper by subjecting the copper matte obtd. from sulfide ore as a raw material to oxygen blowing in the converter. CONSTITUTION:The sulfide core contg. Cu2S and FeS is melted as the raw material in the smelting furnace to form the matte consisting of the FeS and Cu2S, by which the gangue component in the ore is separated as molten slag. The matte is charged into the converter and the oxygen-enriched air, etc., are blown into the converter to convert the FeS to Fe2O3 which is separated away as molten slag by a slag forming agent. The Cu2S is partly oxidized to CuO. The Cu (nearly equal to 99) converted to the blister copper and gaseous SO2 by reacting with the remaining Cu2S. The blister copper is used as anode at the time of electrolytic refining and is made into high-purity electric copper. The solid fuel, such as coke, is blown in an amt. of >=150kg from tuyeres into the converter by determining >=20vol.% of the oxygen in the air to be blown into the converter as the amt. at which the fuel makes perfect combustion. The deficiency of the heat in the converter is compensated by the combustion heat thereof, by which the efficiency of refining from the matte to the blister copper is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating a converter in copper smelting, and more particularly to improvement of heat balance in the operation of a converter.

[0002]

2. Description of the Related Art In copper smelting, the mat produced in a smelting furnace such as a flash smelting furnace is then charged into a converter and processed. When air or oxygen-enriched air is blown into the molten mat in this converter and silicate ore is added, iron sulfide in the mat is oxidized to SO ₂ and the iron oxide reacts with the silicate ore and melts. It forms a slag with a low point (the process for this is called the canning period), while the copper remains white (Cu
₂ S). Then, when the air or oxygen-enriched air is blown into the converter in which the slag having a small specific gravity is discharged and only the white glue is left, the sulfur in the white glue reacts with oxygen and is removed as SO ₂ gas, Crude copper containing about 98% copper and the balance oxygen and precious metal elements is produced (the process for this is called the coppermaking stage). SO ₂ gas generated in smelting furnace and converter is usually recovered as sulfuric acid

In recent years, copper smelting has been aimed at increasing melting, and the mat processing load in a converter has been increasing in response to increasing melting. There are various methods for increasing the mat processing capacity in the converter. Simultaneous blowing of a plurality of converters is the easiest method, but this is not economical because it requires additional exhaust gas treatment equipment and sulfuric acid production equipment.

There is also a method of increasing the unit air flow rate from the tuyere to shorten the blowing time, but in order to do so, it is necessary to increase the blower, and in the converter as it is, it can be easily detected as exhaust gas. This is not economical either, because the amount of body scattering increases and the converter needs to be large, and it is also necessary to add exhaust gas treatment equipment.

[0005] Therefore, as a method of increasing the matting capacity without causing any problems economically, there is a method of increasing the amount of oxygen enriched in the reaction air to shorten the blowing time. However, this increase in oxygen enrichment causes localized heating of the tuyere and the tuyere brick. Also, the blowing time is shortened,
The blowing time cannot be shortened beyond the required slag turning time.

[0006] Therefore, as a method of increasing the mat processing capacity without largely changing the operation load in the converter, the copper produced in the converter by increasing the copper grade in the mat produced from the smelting furnace (hereinafter referred to as mat grade) The method of increasing the amount is generally taken. However, if the matte quality becomes higher, the heat of oxidation reaction during the can-making period will decrease and the heat for melting and reducing the slag of the previous copper-making period will be required, and the heat balance during the can-making period will be the amount of the cooling agent charged. If you cannot adjust with, take measures to increase oxygen enrichment. However, this increase in oxygen content leads to a reduction in the blowing time during the can-making period, and when the blowing time during the can-making period is less than the specified time, the slag during the copper-making period does not melt, or during the copper-making period due to blowing Since the slag and the mat are not agitated and contacted with each other, the situation may occur in which the mat of the slag during the coppermaking period cannot be completely reduced, converted into slag, and discharged outside the furnace. Therefore, the amount of slag remaining in the furnace during the coppermaking period increases. Also, this slag during the copper-making period hinders the discharge of blister copper after the copper-making period ends, that is, blister copper is caught in the slag and remains in the furnace and is carried over to the next can-making period. There is a drawback that a vicious cycle is said that the blowing time during the can-making period is further shortened due to the re-sulfurization reaction of the crude copper thus produced.

[0007]

DISCLOSURE OF THE INVENTION The present invention, in a converter operation during the smelting or smelting period of copper smelting, instead of maintaining a heat balance by increasing or decreasing the oxygen enrichment amount, burns a solid carbon fuel. Provides a method of compensating for heat to maintain the heat balance.

[0008]

In order to achieve the above object, the present inventors have paid attention to the exothermic effect of solid carbon fuel. That is, the present invention, in the operation of the converter smelting stage or the copper making stage of the copper smelting, the solid carbon-based fuel is charged into the furnace from the furnace opening of the copper smelting converter and burns the solid carbon-based fuel. The point is characteristic.

In addition, the present invention relates to the operation of the above converter,
It is characterized in that the amount of solid carbon-based fuel charged into the furnace is the amount of oxygen that completely combusts with 20% by volume or less of oxygen in the gas blown into the furnace from the tuyere.

Further, in the present invention, in the operation of these converters, the amount of solid carbonaceous fuel continuously charged into the furnace is 1
At a point of 50 kg or less, that is, when the total amount of solid carbonaceous fuel charged into the converter exceeds 150 kg, 150
It is characterized in that it is charged into a quantity of less than or equal to kg in multiple times.

[0011]

According to the present invention, in the converter operation in copper smelting, solid carbon fuel is charged from the furnace mouth of the converter during the blowing of oxygen-enriched air, etc. In order to improve the heat balance by compensating for the calorific value generated by burning them in this, when heat is insufficient in the operation of the converter, especially in the operation of the can-making period in the high matte quality operation, It is possible to lengthen the blowing time so as to obtain the slag slagging time.

As the solid carbon fuel, coal, coke, wood (charcoal), and any other so-called carbon-containing fuel can be used, but coke and coal are generally used considering the amount of heat generation. Is desirable. When coal is used, the dust in the exhaust gas may affect the exhaust gas treatment process, that is, the sulfuric acid coloring process in the case of copper smelting, which may affect the sulfuric acid production process. Cheaper coal is suitable as a solid carbon fuel.

Next, it is desirable that the particle size of the solid carbon fuel is fine particles from the viewpoint of reactivity. However, when the solid carbon fuel is charged directly into the furnace through the furnace port, it does not reach the inside of the furnace and the hood or There is a possibility of burning in the waste heat boiler. In addition, when the injection method of fine-grained solid carbon-based fuel is adopted from the tuyere, the fine-grained solid carbon-based fuel may collide with the inner wall of the tuyere and promote wear of the tuyere. It is not economical because it requires additional equipment. Therefore, the direct charging method of the solid carbon fuel having a certain size through the furnace port, which can use the existing equipment, is the easiest and most effective. Considering charging into the furnace during air blowing, the particle size of the solid carbon-based fuel is preferably 30 mm or more.

Further, since the massive solid carbon fuel is burned in the high temperature converter as described above, when coal is used as the solid carbon fuel, the volatile components contained in them are well burned and incomplete. It is also expected to prevent the coloring phenomenon of sulfuric acid due to the volatile components of combustion. Further, since the solid carbon fuel used in this manner is a lump, that is, one having a small surface area, a strong reducing atmosphere unlike when using a powdery solid carbon fuel having a large surface area is less likely to occur, and Considering that the solid carbon fuel used is massive and has a small specific gravity, it is likely that it floats on the surface of the high temperature melt when there are unburned materials. Less likely to interfere.

In the present converter operation of copper smelting, about 20% of the oxygen in the air blown from the tuyere does not react with Fe and S in the mat and remains as oxygen gas according to the balance calculation for oxygen. As the result of the investigation revealed that it will be released outside the reactor, the maximum amount of solid carbon fuel that can be completely burned is about 20% of the oxygen amount in the blown (oxygen-enriched) air. Need to charge as.

Further, the solid carbon fuel is charged in such a manner that the amount of steam that does not exceed the upper limit of the steam generation amount of the waste heat boiler is continuously charged for one time, and the blowing time in the can-making period is set to be equal. By controlling the amount of steam generated and the temperature of the molten metal to be controlled stably by performing the charging in multiple times, it is possible to perform stable operation control, and the maximum amount of solid carbon-based fuel that can be continuously charged in one batch As will be described later, the physical quantity is preferably 150 kg in the current commercial-scale converter and the operation using it.

[0017]

【Example】

Example 1 An example of the present invention will be shown below, and lumpy coal was used as a solid carbon-based fuel. The composition and particle size of agglomerated coal are shown below. Fixed carbon content: 16.8% Ash content: 11.8% Volatile content: 20.1% Moisture content: 10.1% Average particle size: 35 mm The converter used is a PS type converter, and its dimensions are brick inner diameter. It had a diameter of 3.3 m and a body length of 11.9 m, and the agglomerated coal was placed in a dedicated bottle and charged into the furnace from the furnace opening of the converter using a coolant charging chute.

As a preliminary test prior to this test, the boiler steam generation amount charged from the furnace opening was set to 150 kg (the measured value was 147 kg) as the set value for the amount of coal continuously charged for 150 times. Examined. The results are shown in Fig. 1. From this, the maximum value of boiler steam generation is 17.5 tons /
However, the control upper limit of 20 tons / hour was not exceeded, and there was no adverse effect of unburned carbon on the sulfuric acid plant. However, the set value of the charging amount for one time is 200k
When g was used (measured value was 198 kg), a bumping phenomenon of jacket water from the hood jacket was observed.

Therefore, the upper limit of the charging amount for one time is 150
This test was carried out in the canning period so that the maximum treatment amount was kg and the blowing time was equally divided. The conditions and results are shown in Tables 1 and 2 as Test No. Shown as 1.

[0020]

[Table 1]

[0021]

[Table 2]

This test was conducted 64 times, and the numerical values in Tables 1 and 2 are average values per one time. In this test, test No. which is a comparative example in which coal was not charged. Oxygen enrichment was reduced by 2% compared to 2, and lumpy coal was charged as its heat compensation. The charging amount is 307 kg in the first canning period, 134 kg in the first canning period, and the set value of the charging amount for one time is 150 kg, so the first canning period is twice, and the second canning period is Then, it means that the coal was charged once. As a result, in this test, the test No. Compared with 2, it was possible to secure a sufficient blowing time by extending the blowing time of 11 minutes, which is 7 minutes in the first canning period and 4 minutes in the second canning period. Test No. 3 was also applied to the copper-containing content in the slag, which is an index of slag properties. There is no difference compared to No. 2, which means that the heat balance during blowing is sufficiently maintained as in conventional operation.

Example 2 Next, Table 3 and Table 4 show the conditions and results of the example in the case of charging coal in the coppermaking period. The test was performed 5 times, and the numerical values in Tables 3 and 4 are average values per one time. As the method, the oxygen enrichment rate during blowing was the same, and the effect of increasing the melt temperature due to coal charging was investigated by measuring the temperature of the crude copper at the end of the coppermaking period. In this test, the amount of coal charged was 145 kg, which was a comparative example in which no coal was charged. Compared with No. 4, the temperature of blister copper increased by 14 ° C, and the thermal effect due to coal charging was confirmed. From this, it was found that when the temperature of the blister copper during blowing was low, the massive coal charging during the coppermaking period was very effective.

[0024]

[Table 3]

[0025]

[Table 4]

COMPARATIVE EXAMPLE 1 During the smelting period of copper smelting, no lumpy coal was charged and the oxygen enrichment ratio in the blast air was kept at the conventional value, and the operation was carried out 5 times.
The conditions and results are shown in Table 1 and Table 2 as Test No. Shown as 2.

Comparative Example 2 During the copper smelting stage of copper smelting, conventional operations were carried out 5 times without charging lumpy coal, and the conditions and results are shown in Tables 3 and 4.
Test No. Shown as 4.

[0028]

EFFECTS OF THE INVENTION According to the method of the present invention, in the operation of a copper smelting converter, it is effective to increase or decrease the amount of oxygen enriched for reaction depending on the calorific value of the solid carbonaceous fuel directly charged from the furnace mouth of the converter. It is possible to maintain the heat balance during blowing by compensating for the increase or decrease in the heat generation amount or the increase or decrease in the reaction heat due to the increase or decrease in the mat quality. The method of the present invention is particularly effective in the can-making stage of high matte grade operation in which the heat of oxidation reaction is insufficient.

[Brief description of drawings]

FIG. 1 is a diagram showing a change in the amount of boiler steam generated during blowing of a converter for copper smelting, that is, a change in the amount of steam recovered by heat exchange of high-temperature exhaust gas from the converter with a boiler.

Claims (3)

[Claims] 1. A method of operating a copper smelting converter, which comprises charging a solid carbon fuel into the furnace through a furnace opening of the copper smelting converter and burning the solid carbon fuel. 2. The amount of solid carbon-based fuel charged into the furnace is a quantity such that 20% by volume or less of oxygen in the gas blown from the tuyere into the furnace is completely combusted. Operation method of copper smelting converter. 3. The method for operating a copper smelting converter according to claim 1 or 2, wherein the amount of the solid carbon-based fuel continuously charged into the furnace is 150 kg or less.