JP2723572B2 - Flash smelting furnace - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flash smelting furnace for producing a smelting intermediate of copper or nickel sulfide ore from a sulfide concentrate of the metal.

[Conventional technology]

As shown in FIG. 8, a conventional flash smelting furnace 1 has a reaction tower 3 provided with a concentrate burner 2 at the top, and one end connected to a lower part of the reaction tower 3 and A settler 6 having an outlet 4 and an outlet 5, and a settler 6
And a flue gas duct 7 connected to the other end of the plume.

The smelting process by the flash smelting furnace 1 is as follows.

First, smelting raw materials 8 such as sulfide concentrate, flux, auxiliary fuel and the like are blown into the reaction tower 3 from the concentrate burner 2 together with the preheated reaction air 9. In the reaction tower 3, sulfur and iron, which are flammable components of the smelting raw material 8, react with the high-temperature reaction air 9, and the reaction product forms a melt and accumulates in the settler 6. In the settler 6, which is the pool, the melt is made of a mixture of Cu ₂ S and FeS 10 and 2FeO · SiO _{2 due to a} difference in specific gravity. Discharged from mouth 4 Introduced into furnace 12. On the other hand, is extracted from the outlet 5 in response to a request from the converter, which is the next step. The high-temperature exhaust gas 13 generated in the reaction tower 3 is cooled by the exhaust heat boiler 14 through the settler 6 and the exhaust gas path 7. Electrolysis Is heated and held by the heated electric heat. It was mixed with massive ore and massive flux introduced into the furnace 12, and the copper further settled to the bottom of the furnace and contained a small amount of residual copper. Only the exhaust is discharged from the vent 16 to the outside of the furnace.

Incidentally, in such a self-melting smelting furnace 1, it is necessary that the reaction is completed while the smelting raw material 8 falls in the reaction tower 3.
The particles are scattered together with 13 to form smoke and are fixed in volume in the exhaust heat boiler 14, and partly accumulate as undissolved substances on the surface of the melt at the lower part of the reaction tower 3. The smoke ash deposited in the waste heat boiler 14 is recovered and repeated in the flash smelting furnace 1 and the converter. However, as the amount of smoke ash increases, the amount of auxiliary fuel for melting the smoke ash must be increased, resulting in an economic disadvantage. Bring. In addition, the smoke ash fixed in the exhaust heat boiler 14 grows, and not only reduces the heat transfer efficiency in the exhaust heat boiler 14, but also increases the risk that the exhaust heat boiler 14 may be separated and fall and be destroyed. On the other hand, undissolved matter deposited on the melt surface of the settler 6 impedes the formation of 10 and causes large fluctuations in temperature and quality, resulting in great difficulty in the furnace.

In order to avoid such a situation, the smelting raw material 8 and the reaction air 9 are uniformly mixed in the reaction tower 3, and the reaction between the smelting raw material 8 and the reaction air 9 is sufficiently completed. Although it is necessary to obtain a residence time, the conventional flash smelting furnace 1 has not been satisfactory in this respect.
That is, in order to obtain a uniform mixture of the smelting raw material 8 and the reaction air 9, the reaction air 9 must be blown into the smelting raw material 8 at a blowing speed of a certain value or more. This is because the smelting raw material 8 is distributed only in the jet stream formed by the concentrate burner 2, and the entire reaction tower 3 cannot be effectively used, and it is difficult to extend the residence time.

In order to solve the above-mentioned drawbacks of the conventional flash smelting furnace, the present inventors filed Japanese Patent Application No. 63-80038,
As shown schematically in FIG. 7 and FIG. 7, a self-melting smelting furnace having an air blowing pipe 17 for blowing the reaction air 9 into the side wall of the reaction tower 3 was proposed. According to this proposal, the concentrate burner 18 vertically provided at the top of the reaction tower 3 is provided so as to penetrate concentrically through the concentrate concentrate and project below the lower end of the concentrate concentrate. An oxygen injection pipe for separately supplying industrial oxygen, and an auxiliary fuel introduction pipe extending concentrically through the oxygen injection pipe and extending to the lower end of the oxygen injection pipe. According to this self-melting smelting furnace, the smelting raw material and the reaction air can be mixed more uniformly, and the residence time in the reaction tower can be lengthened, so that efficient operation can be performed.

In the flash smelting furnace disclosed in the above-mentioned Japanese Patent Application No. 63-80038, as a result of the test operation, it has been found that there is still room for improvement for efficient flash smelting.

That is, in the flash smelting furnace disclosed in Japanese Patent Application No. 63-80038,
For the purpose of improving the heat balance of the entire operation, activating the smelting reaction, and improving the productivity, etc., a concentrate burner as shown in FIG. 5 was installed and a test operation was performed. This concentrate burner includes a tubular concentrate shot 21 vertically installed on a cradle 20 at the top 19 of the reaction tower,
An oxygen blowing pipe 22 penetrating concentrically through the concentrate orifice 21 and projecting downward from the lower end of the concentrate orifice 21.
And an auxiliary fuel introduction pipe 23 penetrating concentrically through the oxygen injection pipe 22 and extending to the lower end of the oxygen injection pipe 22, and a burner joined to the lower ends of the oxygen injection pipe 22 and the auxiliary fuel introduction pipe 23 The burner chip 24 includes a fuel injection hole 34 in the center, which communicates with the auxiliary fuel introduction pipe 23 and a vertically downward fuel injection hole 34, and a plurality of oxygen injection holes around the fuel injection hole 34 which communicate with the oxygen injection pipe 22. 35 are provided. A dispersing cone 25 (see Japanese Utility Model Application Laid-Open No. 60-38665) was attached to the lower outer periphery of the oxygen injection pipe 22 below the lower end of the concentrate shot 21 as required. Further, the oxygen blowing pipe 22 has a double structure so that cooling water can flow. Reference numeral 26 denotes an inspection hole provided in the concentrate shot 21, which is normally closed.

In the test operation, the concentrate burner concentrate 21
Smelting raw material 8 such as copper concentrate, and auxiliary fuel such as heavy oil 27 from auxiliary fuel introduction pipe 23, and high-pressure oxygen 28 is blown into oxygen blowing pipe 22 to form air blowing pipe 17 on the side wall of reaction tower 3. , Air for reaction 9 was blown in, and the operation was carried out.

As a result, in order to increase the amount of oxygen supplied to the oxygen injection pipe 22 so as to improve the heat balance and achieve the purpose of the productivity improvement tower, high pressure is required, and a large oxygen compressor must be used. As a result, a large amount of electric energy is consumed. In order to avoid this, the flow resistance may be reduced by, for example, increasing the area of the oxygen ejection hole 35 of the burner chip 24, but in this case, since the oxygen ejection speed is reduced, the auxiliary fuel introduction pipe 23 is required. There is a danger of a so-called flashback, in which combustion takes place in the interior. In order to prevent flashback, it is necessary to maintain the oxygen ejection speed usually at 100 m / s or more, preferably at 200 m / s or more, and it is clear from this point that the above means cannot be taken.

Therefore, the high pressure oxygen 28 supplied to the oxygen injection pipe 22 is
An attempt was made to mix the remaining oxygen with the normal reaction air 9 at a low pressure and blow it in at a low pressure. However, this method does not increase the electric energy consumed by the oxygen compressor, but the air blowing pipe on the side wall of the reaction tower 3.
At the top of the reaction tower 3 before the smelting raw material 8 comes into contact with the oxygen-enriched air blown from 17, only combustion of heavy oil 27 occurs,
The smelting raw material 8 is heated and heated, but no oxidation reaction occurs. Accordingly, there has been a problem that the oxygen efficiency is deteriorated and it is impossible to carry out efficient self-melting smelting.

[Problems to be solved by the invention]

The present invention has been made in view of the above-mentioned conventional circumstances, and provides a self-melting smelting furnace that can reduce power costs for blowing high-pressure oxygen and has high oxygen efficiency and can perform efficient self-melting smelting. The purpose is to provide.

[Means for solving the problem]

In order to achieve the above object, in the flash smelting furnace of the present invention, a tubular concentrate shot vertically provided at the top of the reaction tower,
An oxygen injection pipe penetrating concentrically through the concentrate shot and projecting below the lower end of the concentrate shot to blow high-pressure oxygen; and an oxygen injection pipe penetrating concentrically through the oxygen injection pipe. An auxiliary fuel introduction pipe extending to the lower end of the pipe, a fuel injection hole which is joined to the lower end of the oxygen injection pipe and the auxiliary fuel introduction pipe and communicates with the inside of the auxiliary fuel introduction pipe at the center, and communicates with the periphery thereof within the oxygen injection pipe A concentrate burner having a burner chip having a plurality of oxygen ejection holes; and an oxygen conduit provided at the top of the reaction tower so as to blow low-pressure oxygen into the reaction tower from the periphery of the concentrate burner in the reaction tower;
An air blowing pipe is provided on a side wall of the reaction tower so as to blow air for reaction into the reaction tower.

The shape of the oxygen conduit is not particularly limited. For example, as shown in FIG. 1, the oxygen branch is branched from a donut pipe 30 surrounding the concentrate burner, and the burner tip 24 at the lower end of the concentrate burner is formed in the reaction tower 3.
Discharge pipes open diagonally downward on the outer circumference of the pipe
2, a cylindrical body 32 supported concentrically outside the concentrate burner 21 of the concentrate burner and having a lower end opened near the lower end of the concentrate burner in the reaction tower 3 as shown in FIG.
Can be configured.

Also, the fuel outlet 34 and the oxygen outlet of the burner chip 24 are provided.
35 is usually formed vertically downward.

However, preferably, a group of the oxygen orifices 35 are provided at an angle toward the fuel orifices 34 to assist the combustion of the auxiliary fuel and to reduce the smelting raw material 8 falling from the concentrate 21. The risk of digestion can be eliminated. In this case, it is preferable that the other group of the oxygen ejection holes 35 be formed so that the outer periphery of the oxygen injection pipe 22 is inclined outwardly from a virtual plane extending downward.

[Action]

In the flash smelting furnace of the present invention, as shown in FIG. 1 or FIG. 2, high-pressure oxygen 28 only necessary for combustion of auxiliary fuel such as heavy oil 27 is supplied from the oxygen injection pipe 22 of the concentrate burner. The remaining oxygen required for blowing and efficient flash smelting is supplied through an oxygen conduit 29. Since the oxygen supplied from the oxygen conduit 29 may be low-pressure oxygen 33 and therefore industrial oxygen can be used as it is, the power of the oxygen compressor is greatly reduced as compared with the case where the total oxygen amount is supplied at a high pressure. In consideration of the flammability of the concentrate, low pressure oxygen 33 from the oxygen conduit 29 is used to prevent flashback.
Is preferably 20 to 30 m / s. The reaction air 9 is supplied from an air blowing pipe 17 provided on the side wall of the reaction tower 3 shown in FIGS. 6 and 7.

Heavy oil 27 supplied to the auxiliary fuel introduction pipe 23 of the concentrate burner
Immediately after the auxiliary fuel such as is discharged from the fuel discharge hole 34 of the burner chip 24 into the reaction tower 3, it is ignited and burned by the high-pressure oxygen 28 blown from the oxygen blowing pipe 22, and the concentrate shot 21.
The smelting raw material 8 that has fallen from and is dispersed by the dispersion cone 25 is heated and heated. The smelting raw material 8 heated and heated has an oxygen conduit 29
Low-pressure oxygen 33 is blown from the reaction tower 3, an oxidation reaction is started at the upper part of the reaction tower 3, and further, an air blowing pipe 17 on the side wall of the reaction tower 3.
The oxidation reaction takes place more completely by means of the reaction air 9. As a result, also in the upper part of the reaction tower 3, sufficient oxygen is supplied from the oxygen conduit 29 and an oxidation reaction occurs.
High oxygen efficiency can be achieved.

〔Example〕

FIG. 1 is a sectional view showing a part of a concentrate burner and an oxygen conduit of a flash smelting furnace according to the present invention used in the present embodiment, which has a diameter provided with an air blowing pipe on a side wall as shown in FIG. 1.5m, height
A test flash smelting furnace with a 3.4 m reaction tower and a 6 m long settler was equipped. The oxygen conduit 29 in FIG. 1 has been described above, and the configuration of the concentrate burner is the same as that in FIG. However, as shown in FIGS. 3 and 4 (the cooling water passage is omitted), the burner tip 24 has a fuel injection hole communicating with the inside of the auxiliary fuel introduction pipe 23 at the center.
34 is provided vertically downward, and a plurality of oxygen ejection holes 35 communicating with the oxygen injection pipe 22 are provided around the fuel ejection holes 34, and 35a of the oxygen ejection holes 35 are inclined toward the fuel ejection holes 34. The group 35b and the group 35b are inclined toward the outside from an imaginary plane extending downward on the outer periphery of the oxygen blowing pipe 22.

Using the above smelting furnace, the following three cases of the test operation were carried out under the operation conditions shown in the following table; Case 1: In accordance with the present invention, a part of oxygen was converted into high-pressure oxygen 28 from the oxygen blowing pipe 22. The remaining oxygen was supplied as low-pressure oxygen 33 from the oxygen conduit 29, and the reaction air 9 was supplied from the air blowing pipe 17.

Case 2: The entire amount of oxygen was blown as high-pressure oxygen 28 from the oxygen blowing pipe 22 and the reaction air 9 was supplied from the air blowing pipe 17.

Case 3: Part of the oxygen is blown as high-pressure oxygen 28 from the oxygen blowing pipe 22, and the remaining oxygen is blown as the low-pressure oxygen in the air blowing pipe 17.
From the reaction air 9 and supplied.

The results of the test run, together with the operating conditions, are summarized in the table below.

As can be seen from the above results, there is no significant difference in the smoke ash generation rate in any case, but in case 2, the power for converting the total amount of oxygen to high pressure oxygen is extremely high, and in case 3, the oxygen efficiency and quality are extremely low. . On the other hand, in Case 1 of the present invention, the oxygen efficiency was high, high quality was obtained, and the power for high-pressure oxygen could be suppressed low.

In the case of the flash smelting furnace equipped with an oxygen conduit 29 composed of a pair of cylinders 32 shown in FIG. 2, the same test operation was performed as in the above-described embodiment, and almost the same operation results were obtained.
Is sprayed to the vicinity of the lower end of the concentrate ore 21, so that a phenomenon such as deposition of the concentrate on the lower end of the concentrate ore 21 is likely to occur.

1 and 2, even when the dispersion cone 25 is not provided on the outer periphery of the lower end of the oxygen blowing pipe 22, as a result of the same test operation, the case 1 of the present invention Showed significant differences as indicated above.

〔The invention's effect〕

According to the present invention, it is possible to reduce power costs for injecting high-pressure oxygen, achieve high oxygen efficiency, improve productivity such as obtaining high quality, and perform efficient self-melting smelting. Can be.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a part of a concentrate burner and an oxygen conduit in a flash smelting furnace according to one embodiment of the present invention.
The figure is a longitudinal sectional view showing a concentrate burner and an oxygen conduit in a flash smelting furnace of another specific example. FIG. 3 is a longitudinal sectional view showing the burner tip of the concentrate burner in detail, and FIG. 4 is a transverse sectional view thereof. FIG. 5 is a longitudinal sectional view showing a concentrate burner and an oxygen blowing pipe in a conventional flash smelting furnace. 6 and 7 are a longitudinal sectional view and a transverse sectional view of a portion of a reaction tower in which an air blowing pipe is provided on a side wall of the reaction tower of the flash smelting furnace. FIG. 8 is an explanatory view of a general flash smelting furnace. 1 ... smelting smelting furnace 2 ... concentrate burner 3 ... reaction tower 4 ... Vent 5: Vent, 6: Settler 7: Flue gas, 8: Smelting raw material 9: Air for reaction, 10 13… High-temperature exhaust gas, 14… Exhaust heat boiler 15 …… Electrode, 16 …… Outlet 17 …… Air injection pipe, 18 …… Concentrate burner 19 …… Reaction tower top, 20 …… Stack 21 …… Concentrate shot, 22 Oxygen injection pipe 23 Auxiliary fuel introduction pipe 24 Burner tip 25 Dispersion cone 26 Inspection hole 27 Heavy oil 28 High pressure oxygen 29 Oxygen conduit 30 ... Donut tube 31 ... Discharge tube, 32 ... Cylinder 33 ... Low-pressure oxygen, 34 ... Fuel outlet 35 ... Oxygen outlet

Claims (3)

(57) [Claims] 1. A tubular concentrate chute suspended from the top of a reaction tower, and a high-pressure oxygen blown concentrically through the concentrate chute and projecting downward from a lower end of the concentrate chute. An oxygen injection pipe to be inserted, an auxiliary fuel introduction pipe penetrating concentrically through the oxygen injection pipe and extending to the lower end of the oxygen injection pipe; A concentrate burner comprising a fuel outlet communicating with the fuel inlet pipe and a burner chip having a plurality of oxygen outlets surrounding the fuel outlet and communicating with the inside of the oxygen inlet pipe; and a concentrate burner provided at the top of the reaction tower. Self-melting smelting characterized by comprising: an oxygen conduit for blowing low-pressure oxygen from around the concentrate burner into the reaction tower; and an air blowing pipe provided on a side wall of the reaction tower and blowing air for reaction into the reaction tower. Furnace. 2. An oxygen conduit comprising a plurality of discharge pipes branching from a donut pipe surrounding a concentrate burner and opening obliquely downward and inward on the outer periphery of a burner chip at the lower end of the concentrate burner in the reaction tower. Claim (1), characterized in that:
Self-melting smelting furnace as described. 3. An oxygen conduit is concentrically supported outside a concentrate chute of a concentrate burner, and a lower end is formed of a cylindrical body opened near a lower end of the concentrate burner in the reaction tower. A flash smelting furnace according to claim 1.