JPH0747786B2 - Operation method of flash smelting furnace - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for operating a flash smelting furnace for performing non-ferrous metal smelting.

[Conventional technology]

One of the smelting furnaces that uses sulphide concentrate as a raw material is a flash smelting furnace, and Fig. 3 shows an example of the configuration of this type of flash smelting furnace called the so-called auto-kump flash smelting furnace. In the figure, the flash smelting furnace 1 has a reaction tower 3 provided with a concentrate burner 2 at the top and one end connected to the lower part of the reaction tower 4 and a side wall provided with a calami outlet 4 and It is basically composed of a settler 6 provided with a leather outlet 5 and a waste smoke path 7 connected to the other end of the settler 6. In the operation of such an auto-kump type flash smelting furnace, the smelting raw material 8 such as sulfide concentrate, flux and auxiliary fuel is blown to the reaction tower 3 through the concentrate burner 2 together with a part of the reaction air 9. Get caught.
Then, in the reaction tower 3, sulfur and iron, which are combustible components of the smelting raw material 8 heated by the combustion of the auxiliary fuel, react with the heated reaction air 9 and are melted. It is stored in the settler 6 in the state. Further, in the settler 6 as the hot water pool, the pooled solution is a mixture of Cu ₂ S and FeS due to the difference in the specific gravity of its components.
Separated into 0 and Karami 11 containing 2FeO.SiO ₂ as the main component. Then, the Karami 11 is discharged from the Karami discharge port 4 and introduced into the electric smelting furnace 12, while the river 10 is appropriately discharged from the Kawa discharge port 5 in accordance with the request from the converter in the next step. The kalami 11 that has entered the electrolysis furnace 12 is further heated and held by the heat generated by the energization from the electrode 13, and is mixed with the lump ore or lump flux that is charged into the electrolysis furnace 12 as necessary. However, at this time, the copper component is further deposited on the bottom of the furnace, and only the kelami containing the slightly remaining copper component is discharged from the outlet 14 to the outside of the furnace. The high temperature waste gas 15 generated in the reaction tower 3 is cooled by the waste heat boiler 16 via the settler 6 and the waste flue 7.

In the auto-kump type self-melting smelting furnace, since the adjustment of the degree of oxidation of the smelting raw material and the adjustment of the smelting temperature can be performed independently of each other,
It is suitable for purchasing mines and smelters where the composition of raw materials must be changed.

However, in such a conventional flash smelting furnace, there has been a problem that a sufficient amount of heat for melting the smelting raw material 8 first cannot be obtained. That is, normally, the retention time of particles of the smelting raw material 8 blown through the concentrate burner 2 is about 1
Seconds, and during this time the particles have to be dissolved by elevating their temperature to their ignition temperature and reacting with the oxygen in the reaction air 9, for which purpose the reaction air 9 must be preheated. Although it is necessary to quickly raise the temperature to the ignition temperature, the upper limit temperature of the reaction air 9 is restricted to 400 to 500 ° C due to the heat resistant temperature of the material of the smelting furnace equipment, and the preheating is sufficient. As a result, it is inevitable that not only the smoke ash generation rate becomes high, but also the oxygen utilization rate, that is, the oxygen efficiency becomes low.

Therefore, in order to solve such a problem, a method using oxygen-enriched air as a reaction air has been put into practical use. For example, according to the apparatus disclosed in Japanese Patent Publication No. 59-41495, industrial oxygen and sulfur are used. Focusing on the high reactivity with the concentrate, all or part of the oxygen for oxygen enrichment is injected into the concentrate chute and air or oxygen enriched air is blown from the venturi section of the concentrate burner. To uniformly mix and disperse the smelting raw material such as sulfide concentrate and oxygen,
There are some that are designed to improve oxygen efficiency.

On the other hand, when the degree of mixing of the smelting raw material blown from the concentrate burner 2 into the reaction tower 3 of the furnace 1 and the oxygen-enriched oxygen or the oxygen-enriched reaction air is poor, the smelting raw material is reacted. The utilization efficiency of oxygen, that is, the oxygen efficiency decreases. When the oxygen efficiency is low, it becomes necessary to supply more oxygen-enriching oxygen or oxygen-enriched reaction air than necessary, and this increases the amount of auxiliary fuel for raising the temperature of the excess reaction air supplied. It also leads to an increase in the smoke ash generation rate with an increase in the amount of waste gas.

In order to solve such problems, for example, Japanese Utility Model Laid-Open No. 1-78161, Japanese Utility Model Laid-Open No. 1-78162, and Japanese Patent Application No. 1-56
There is one described in No. 032.

The one described in Japanese Utility Model Laid-Open No. 1-78161 and Japanese Utility Model Laid-Open No. 1-78162 includes a blower pipe, a venturi portion concentrically connected to the lower surface of one end of the blower pipe, and an end portion of the blower pipe from the upper side. A concentrate burner that has a concentrate chute concentrically extended through the venturi section and penetrates into the venturi section and blows reaction air sent from a blower pipe between the concentrate chute and the venturi section into the top of the reaction tower ( Hereafter, referred to as a conventional concentrate burner.) In which one or two air conditioners were provided in the blower pipe close to the venturi section so that the reaction air could be blown out uniformly from the venturi section. Is.

Further, the one described in Japanese Patent Application No. 1-56032 has a blower shaft of each nozzle in a position near the central portion of the side wall of the reaction tower at a position symmetrical to a vertical line passing through the center point of the reaction tower on the side wall. One or more sets of blower nozzles mounted so that the direction thereof is the vertical direction are provided, and the blower nozzles rotate within the vertical plane including the nozzle blow axis direction around the mounting position as necessary. As a result, by blowing a part of the reaction air from the blowing nozzle and making the entire reaction tower turbulent, the smelting raw material blown into the reaction tower from the concentrate burner is evenly distributed in the reaction air. , And the residence time in the reaction tower becomes longer, whereby the smelting raw material such as concentrate and the reaction air are sufficiently reacted, and the oxygen efficiency of the reaction air is further improved, and as a result, Made it possible to reduce the smoke ash generation rate and prevent the formation of undissolved substances. It is a thing.

[Problems to be Solved by the Invention]

However, in the device described in Japanese Patent Publication No. 59-41495, since oxygen for oxygen enrichment is injected into the concentrate chute, the sulfide concentrate in the concentrate chute reacts with oxygen to cause the chute. There was a problem that it was welded inside and blocked the concentrate chute, making continuous operation impossible.
Further, in this apparatus, since the concentrate particles are sufficiently suspended in the oxygen stream, a good in-furnace reaction can be performed, but the air stream does not spread, so SO ₂ generated by combustion is generated.
The concentrate particles are likely to be carried out to the outside of the furnace together with the exhaust gas containing, and not only the smoke ash generation rate cannot be reduced, but also the smoke ash generation rate rather increases depending on the operating conditions.

In addition, in those disclosed in Japanese Utility Model Laid-Open No. 1-78161 and Japanese Utility Model Laid-Open No. 1-78162, a ventilation plate is installed in a conventional concentrate burner in order to make the ventilating section of reaction air uniform. Although it is a technology to make full use of the performance of the conventional concentrate burner, the performance of the conventional concentrate burner is only 9% or more in the smoke ash generation rate and 80% or less in the oxygen efficiency in the first place. There is no better performance than this.

Further, according to the example of Japanese Patent Application No. 1-56032, the best result obtained in this operation was reported to be a value of 5.8% in smoke ash generation rate and 100% in oxygen efficiency. It is clear that the smelting furnace and operating method are superior to the flash smelting furnace and operating method using the conventional concentrate burner. However, according to the subsequent studies, in the operation according to the above-mentioned example, when the ratio of silicate ore other than the sulfurized concentrate as a smelting raw material was increased, the smoke ash generation rate did not change so much, but the oxygen efficiency decreased. It became clear that it would do. This is considered to be due to the following reasons.

According to this operating method, in order to blow a part of the reaction gas from the blowing nozzle to the jet stream formed by the concentrate burner and make it a turbulent flow that spreads throughout the reaction tower,
The smelting raw material blown into the reaction tower from the concentrate burner together with the auxiliary fuel and the reaction air is uniformly dispersed in the reaction air. Here, silicate ores other than sulphurized concentrate, iron refined powder, copper syrup, smoke ash, etc., which are mulched as smelting raw materials, are non-self-combustible substances and inhibit combustion of the concentrate inside the reaction tower. In particular, silicate ore has a high melting point of 1720 ° C, which is the main component of SiO ₂ ,
It is clear that the degree of inhibition of the flammability of the concentrate is high,
In this operating method, when the proportion of silicate ore added is increased, the burning concentrate and silica are uniformly dispersed, so that the silicate ore acts as if it were a powder extinguishing agent. To do. As a result, the temperature of the burning concentrate particles itself is lowered, and the oxidation reaction of the concentrate itself is suppressed,
Oxygen efficiency is reduced.

In view of the above problems, the present invention is a self-melting smelting furnace for non-ferrous metal sulfides that uses oxygen-enriched air as reaction air, which can significantly improve oxygen efficiency and reduce smoke ash generation rate. It is intended to provide a method of operating a furnace.

[Means for Solving the Problems]

One of the operating methods of the flash smelting furnace according to the present invention is a reaction tower, a settler having one end connected to a lower part of the reaction tower and a side wall provided with a drainage port and a drain port, A waste flue connected to the other end of the settler, and at least one concentrate burner provided at the top of the reaction tower and / or at the ceiling of the settler, wherein the concentrate burner is at least the concentrate. A chute, an oxygen blowing tube inserted into the concentrate chute, and an auxiliary fuel burner inserted into the oxygen blowing tube,
In a method of operating a flash smelting furnace, the lower end of the oxygen blowing pipe is made to project below the lower end of the concentrate chute, and at least the auxiliary amount of oxygen necessary for burning the smelting raw material and auxiliary fuel is supplemented. It is characterized in that an amount of oxygen for fuel or more is blown into the furnace as industrial oxygen through the oxygen blowing pipe.

In addition to the above configuration, the other one is that all of the oxygen amount necessary for combustion of the smelting raw material and the auxiliary fuel is blown into the furnace as industrial oxygen through the oxygen blowing pipe. It has a feature.

Further, in addition to the above configuration, the other one is characterized in that the lower end of the auxiliary fuel burner is at the same level as the lower end of the oxygen blowing pipe.

[Action]

According to the above configuration, among the smelting raw materials supplied from the concentrate chute, the non-ferrous metal sulfide concentrate having self-combustibility such as copper, nickel and lead is radiant heat from the furnace wall or high temperature exhaust gas or auxiliary fuel burner. The temperature rises and ignites rapidly due to the flame formed by. Then, since industrial oxygen in excess of the amount of oxygen for combustion of the auxiliary fuel is blown through the oxygen blowing pipe, the ignited sulfide concentrate is immediately mixed with industrial oxygen supplied from the oxygen blowing pipe. Reacting to form Kawa, Karami and exhaust gas, of which Hot Kawa and Karami collide with each other while falling in the reaction tower and the particles become enlarged, and silicate ore and copper slag added as smelting raw materials. , Collides with non-self-burning substances such as iron refined powder and smoke ash, and melts them. Further, some of the non-self-burning substances are also melted by the radiant heat generated by the combustion of the sulfide concentrate and the high temperature exhaust gas. here,
Since the industrial oxygen supplied from the oxygen blow-out pipe is usually 90% or more at the oxygen temperature, the oxidation reaction (combustion) of the sulfide concentrate is quicker than the oxidation reaction in the case of air or oxygen-enriched air. . The reason is that air and oxygen-enriched air contain a large amount of inert nitrogen other than oxygen, and this hinders the reaction between the sulfide concentrate and oxygen. Exhaust gas mainly composed of SO ₂ released during combustion of sulfide concentrate does not require heating of nitrogen or the like in the case of industrial oxygen, so exhaust gas generated when air or oxygen-enriched air is used. Will be hotter than. With the above-described action, the smelting raw material supplied into the reaction tower efficiently reacts with industrial oxygen, so that it is possible to carry out self-melting smelting with a low smoke ash generation rate and high oxygen efficiency.

In particular, if all the amount of oxygen required for combustion of the smelting raw material and the auxiliary fuel is blown into the furnace as oxygen for industrial use through the oxygen blowing pipe, the addition ratio of non-self-combustible substances other than the sulfide concentrate as the smelting raw material is increased. Even if it is increased, a low smoke ash generation rate and high oxygen efficiency can be obtained by the above principle.

Further, best results are obtained if the lower end of the auxiliary fuel burner is at the same level as the lower end of the oxygen blowing tube. This is because a heavy fuel oil combustion frame is formed near the lower end, the reaction of the smelting raw material passing through this frame is completed in an extremely short time, and as a result, enlargement due to mutual collision between particles in the reaction tower. This is because the time for can be extended.

〔Example〕

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

Embodiment 1 FIG. 1 is a schematic view of a concentrate burner 2'of a flash smelting furnace used in this embodiment, in which 17 is a wind box having a narrowed portion 17a and an opening 17b expanding downward. , 18 is a concentrate chute suspended in the central portion of the wind box 17 so that the lower end is located slightly below the narrowed portion 17a,
Reference numeral 19 is an oxygen blowing tube that is concentrically inserted into the concentrate chute 18 and has a dispersion cone 20 on the outer periphery of the lower end that projects downward from the tip of the concentrate chute 18, and 21 is an oxygen blowing tube.
The auxiliary fuel burner is concentrically inserted into 19 and positioned so that its lower end is at the same level as the lower end of the oxygen blowing pipe 19. And, a reaction tower 3 having an inside diameter of 1.5 m and a height of 4.0 m equipped with such a concentrate burner 2'at the top and an inside diameter of 1.5 m
And a medium-scale test furnace equipped with a settler 6 with a length of 5.25 m (see Fig. 3) and a throughput of about 0.8 t / h, and the test operation for 4 days under the conditions shown in Table 1 below. I went.

Here, in Table 1, the industrial oxygen amount means the amount of industrial oxygen used as the enrichment oxygen, and the oxygen blowing pipe oxygen amount means the oxygen blowing pipe 19 of the industrial oxygen. It means the amount of oxygen blown into the furnace. Then, in the test operation No. 1 (Comparative Example 1), industrial oxygen and air were mixed and the whole amount was supplied from the wind box 17, and in the test operation No. 2, for burning heavy oil as an auxiliary fuel. Only the amount of oxygen required (54 Nm ³ /
h) is blown into the furnace from the oxygen blowing pipe 19, the rest is mixed with air and fed into the furnace from the wind box 17, and in the test operation No. 3, the total amount of industrial oxygen (134 Nm ³ / h ) Was blown into the furnace through the oxygen blowing pipe 19. In these cases (No. 1 to No. 3), the lower end of the auxiliary fuel burner 21 is adjusted so as to project downward from the tip of the oxygen blowing pipe 19. Further, the test operation No. 4 is similar to the above-described test operation No. 3 except that the lower end of the auxiliary fuel burner 21 is positioned at the same level as the lower end of the oxygen blowing pipe 19. Is.

Next, the results of each of the test operations No. 1 to No. 4 are shown in Table 2 below.

As is clear from the results shown in Table 2, it is clear that the smoke ash generation rate is reduced and the oxygen efficiency is improved by injecting oxygen in excess of the oxygen amount for the auxiliary fuel from the oxygen injection pipe 19. Is. That is, normally, the ignition / combustion of the auxiliary fuel occurs prior to the ignition / combustion of the concentrate, but if the amount of industrial oxygen blown from the oxygen blowing pipe 19 is at least the oxygen amount necessary for the combustion of the auxiliary fuel or more. As a result, the concentrate and oxygen react violently in the oxygen-rich portion of the generated air flow,
This significantly reduces the overall reaction time.

Also, especially in the case of test operation No. 4, the total amount of enriching oxygen (134N
m ³ / h) is not only blown into the furnace from the oxygen blowing pipe 19, but the lower end of the oxygen blowing pipe 19 and the auxiliary fuel burner 21 are at the same level, so that the best operation result is obtained. Is a violent heavy oil combustion frame is formed near the tip of the oxygen blowing pipe 19 and the auxiliary fuel burner 21, the smelting raw material passing through this frame is immediately heated, and the reaction of the smelting raw material occurs in an extremely short time. Completed, resulting in reaction tower 3
This is because it is possible to extend the time for enlargement due to mutual collision of particles inside.

Further, the following Tables 3 and 4 show that, in the above-mentioned medium-scale test furnace, the lower ends of the oxygen injection pipe 19 and the auxiliary fuel burner 21 were adjusted to the same level, and only the industrial oxygen was used as the reaction air. The operating conditions and results of test operation No. 5 performed by blowing the entire amount into the furnace from the oxygen injection pipe 19 are shown.

According to the test operation No. 5, the smoke ash generation rate was remarkably reduced, and in particular, the oxygen utilization efficiency could be made 100%.

As described above, in this embodiment, the oxygen efficiency can be improved, but the dispersion cone 20 in the flash smelting furnace uniformly disperses the smelting raw material, and so-called heap (lump of undissolved material) is generated. Is being prevented.

When the same conditions as in the above-mentioned test operation No. 5 were applied and oxygen was blown into the furnace from the concentrate chute 18 instead of the oxygen blowing pipe 19, the concentrate chute was completed within 2 hours after the start of the test operation.
The concentrate burned inside 18 and the concentrate chute 18 was blocked.

Example 2 FIG. 2 is a schematic view of a concentrate burner 2 ″ of a flash smelting furnace used in this example. It is made by removing the concentrate burner 2 ″ at the top with an inner diameter of 1.5 m and the height from the ceiling to the settler level is 2.
Using a small experimental flash smelting furnace equipped with a 5m reaction tower 3 and a settler 6 with an inner diameter of 1.5m and a length of 5.25m, the processing amount of the concentrate is about
0.8t / h, so that the target quality is 50%,
The operation was performed under the conditions shown in Table 1 below. In addition, test operation
No. 1 is the case where heavy oil is supplied from the auxiliary fuel burner 21 at a rate of 7 l / h to form a flame, and the test operation No. 2 is when no heavy oil is supplied, for 3 days and 2 days respectively. Was carried out.

The results are shown in Table 2 below.

Comparative Example 2 Using the same small experimental flash furnace as in Example 2 with one conventional concentrate burner on the top, the target Kawa quality was 58.
The operation was carried out for 2 days under the condition No. 3 shown in Table 3 below so that the ratio would be%. Further, using the same small flash furnace for experiment as in Example 2 in which one concentrate burner at the top and one set of air-blowing nozzles near the center of the side wall thereof were provided in Japanese Patent Application No. 1-56032,
The operation was carried out for 3 days under the condition No. 4 shown in Table 3 below so that the target quality of Kawa was 55%. In Table 3 below, L is the height of the reaction tower, and I is the distance from the ceiling of the reaction tower to the blowing nozzle.

The results are shown in Table 4 below.

As is clear from the comparison of the results of Example 2 and Comparative Example 2,
It can be seen that the operation method of the present invention enables operation with a lower smoke ash generation rate and higher oxygen efficiency than in conventional flash smelting furnaces.

Example 3 Using the same small experimental flash furnace as in Example 2, operation was carried out under the operating conditions shown in Table 1 below so that the target quality of the river would be 50%. The test operation No. 1 is the one in which the addition rate of silicate ore to the concentrate is increased, and the test operation No. 2 is the one in which silica and iron refined powder are added to increase the addition rate of the non-self-burning substances, for 2 days each. It was operated for 3 days.

The results are shown in Table 2 below.

Comparative Example 3 Similar to the test operation No. 4 of Comparative Example 2, a small experimental flash furnace equipped with one concentrate burner at the top and a pair of blower nozzles near the center of the side wall of the burner was used. Under the operating conditions shown in the table, the operation was carried out so that the target quality of Kawa was 55%. Test operation No. 3 is for increasing the addition rate of silicate ore to concentrate, and test operation No. 4 is for increasing the addition rate of non-self-burning substances by adding silicate ore and iron refined powder. Days, 3
It was operated for a day. In Table 3 below, L is the height of the reaction tower, and I is the distance from the ceiling of the reaction tower to the backflow nozzle.

The results are shown in Table 4 below.

As is clear from the comparison between the results of Example 3 and Comparative Example 3, even if the operation method of the present invention increases the proportion of the non-self-burning substance added to the concentrate, low smoke ash generation was impossible with the conventional operation method. It is understood that it is possible to operate the flash furnace with high efficiency and high oxygen efficiency.

The test operation N of Comparative Example 2 equipped with a conventional concentrate burner N
Using the same experimental small flash furnace as in o.3, the processing amount of concentrate was 0.823t /
When the operation was carried out under the conditions of a concentrate burner with a h, silicate ore processing amount of 0.115 t / h, unmelted matter was deposited on the surface of the molten metal directly under the reaction tower, and the operation could only be performed for 4 hours.

〔The invention's effect〕

As described above, according to the method for operating a flash smelting furnace according to the present invention, in a flash furnace for non-ferrous metal oxides that uses oxygen-enriched air as reaction air, the oxygen efficiency is greatly increased and the smoke ash generation rate is reduced. It has an important practical advantage of being able to achieve

[Brief description of drawings]

FIG. 1 is a schematic diagram of a concentrate burner of a flash smelting furnace used in Example 1, FIG. 2 is a schematic diagram of a concentrate burner of a flash smelting furnace used in Examples 2 and 3, and FIG. The figure is a diagram showing a configuration of a conventional flash smelting furnace. 1 …… Smelting and smelting furnace, 2 ′, 2 ″ …… Concentration burner, 3 ……
Reaction tower, 4 ... Karami outlet, 5 ... Kawa outlet, 6 ...
… Settler, 7 …… Waste flue, 8 …… Smelting raw material, 10 …… Kawa, 11 …… Kalami, 12 …… Electric smelting furnace, 13 …… Electrode,
14 …… Vent, 16 …… Waste heat boiler, 17 …… Windbox, 18 …… Concentrate chute, 19 …… Oxygen blowing pipe, 20
…… Dispersion cone, 21 …… Auxiliary fuel burner.

Claims (3)

[Claims] 1. A reaction tower, a settler having one end connected to a lower portion of the reaction tower and having a side opening provided with a drainage port and a drainage port, and a waste flue connected to the other end of the settler. And at least one concentrate burner provided on the top of the reaction tower and / or the ceiling of the settler,
A smelting and refining furnace in which the concentrate burner is composed of at least a concentrate chute, an oxygen blowing tube inserted into the concentrate chute, and an auxiliary fuel burner inserted into the oxygen blowing tube. In the operating method, the lower end of the oxygen blowing pipe is made to project below the lower end of the concentrate chute, and at least oxygen for the auxiliary fuel is contained in the amount of oxygen required for combustion of the smelting raw material and the auxiliary fuel. A method for operating a flash smelting furnace, characterized in that an amount of not less than industrial oxygen is blown into the furnace through the oxygen blowing pipe. 2. The whole amount of oxygen required for combustion of the smelting raw material and the auxiliary fuel is blown into the furnace as industrial oxygen through the oxygen blowing pipe. The operating method of the described self-smelting and smelting furnace. 3. The flash smelting furnace according to claim 1, wherein the lower end of the auxiliary fuel burner is at the same level as the lower end of the oxygen blowing pipe. Operating method.