JPH0586422A - Method for operating self-melting smelting furnace - Google Patents

Abstract

PURPOSE:To improve the trouble, such as decrease of inner vol. in a settler by efficiently melting flue cinder, etc., dropped in a large quantity to the settler below an exhausting flue for self-melting smelting furnace and the stuck material produced in this settler without damaging the furnace wall. CONSTITUTION:In an operating method for self-melting smelting furnace 1 having a reaction tower 5, a concentrated ore burner 4 arranged at the top part of the reaction tower 5, a settler 6 arranged as connecting with one end at the lower part of the reaction tower 5, the exhaust flue 13 stood up as connecting with the other end of the settler 6 and a boiler 14 arranged as connecting with the side surface of the exhaust flue 15, a lance pipe 17 is inserted into the furnace penetrating a roof horizontal part in the exhaust flue or a roof inclining part in the exhaust flue. To melting body in the settler 6 or the stuck material in the furnace bottom, at least fine coal and reacting gas are injected through this lance pipe 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a flash smelting furnace for producing a mat, which is a smelting intermediate of the metal, from copper or nickel sulfide ore, and particularly to smoke ash and furnace. The present invention relates to an operating method for improving operational troubles in a settler due to bottom adhered substances.

[0002]

2. Description of the Related Art In a conventional copper smelting flash smelting furnace, as shown in FIG. 3, a powdered concentrate 2 reacts with a reaction gas 3 such as preheated air from a furnace burner 4 to a furnace reaction. It is blown into the tower 5. In the reaction tower 5, sulfur and iron, which are combustible components in the powdery concentrate 2, react with the high-temperature reaction gas 3 to be dissolved, and are stored in the settler 6. In the settler 6 which is the hot water pool, the solution is divided into a mat 7 which is a mixture of Cu ₂ S and FeS and a slag 8 which contains 2FeO.SiO ₂ as a main component due to the difference in specific gravity. The slag 8 is discharged from the slag outlet 9 and introduced into the electric smelting furnace 10. On the other hand, the mat 7 is extracted from the mat outlet 11 in accordance with the demand of the converter in the next step.

On the other hand, high-temperature exhaust gas 12 from the flash smelting furnace 1 is cooled by a boiler 14 through a settler 6 and a smoke exhaust passage 13. The slag 8 that has entered the electric smelting furnace 10 is the electrode 15
The slag is heated and held by the electric heat supplied by the slag and is mixed with the lump ore or flux charged into the electric smelting furnace 10 if necessary, and the copper content is further settled on the bottom of the furnace, and a slight amount of the remaining copper content is contained in the slag. Only 8 is discharged out of the system through the outlet 16.

In the above conventional flash smelting furnace, there is a problem in that the settler 6 below the smoke exhaust channel 13 causes troubles due to smoke ash and a substance adhering to the furnace bottom. That is, while the gas in the furnace flows to the reaction tower 5, the settler 6, the flue gas duct 13, and the boiler 14, the wind direction suddenly changes, especially near the flue gas duct, and the temperature of the gas also drops. For this reason, smoke ash or solution particles contained in the gas fall from the gas, or once adhere to the furnace wall or the flue wall and then cooled, the settler 6 below the flue gas duct 13 is cooled.
To fall. When the settler 6 has a large amount of a solution such as slag 8 or the like, the smoke ash or the like that has fallen on the settler 6 is dissolved in the slag 8 or the like, or is discharged from the furnace through the slag outlet 9 together with the slag 8. However, when the settler 6 contains little or no solution such as slag 8, the falling smoke ash or the like does not dissolve and remains as a sticking substance on the furnace bottom, which reduces the internal volume of the settler 6 and reduces slag. Slag outlet 9
It is difficult to discharge the gas from the room, and it causes problems such as narrowing the space through which the gas passes. That is, smoke exhaust 1
The settler 6 under 3 is located farthest from the hottest reaction tower 5, and as described above, low-temperature smoke ash and the like are constantly dropped, so that the settler 6 is easily cooled. It is the location, and further, the furnace temperature deteriorates, the solution temperature drops, the furnace bottom coating becomes abnormally thick, and a large amount of viscous slag composed of magnetite etc. is generated and sticks to the furnace bottom and side walls. There is a large amount of these, and these furnace bottom adhered substances may bulge or be exposed near the surface of the settler 6. Particularly, in a flash smelting furnace of the type in which the slag 8 overflows from the slag outlet 9, the surface of the mat 7 descends when the mat 7 is pulled out from the mat outlet 11, and It is easily exposed from the surface of the solution of the settler 6.

As a countermeasure against these troubles, a method of raising the temperature of the reaction gas 3 or burning a burner in the settler 6 to raise the temperature of the melt to dissolve the adhered substance at the bottom of the furnace, FeO / of slag Although methods such as lowering the SiO ₂ ratio or lowering the matte quality to suppress the generation of magnetite are adopted, a large amount of smoke ash falling on the settler 6 can be quickly dissolved or a large amount of furnace can be generated. It was very difficult to dissolve the bottom stick. Further, as a direct method of removing the sticky matter attached to the furnace wall, etc., coarse-grained carbonaceous material such as coarse-grained coke was provided on the side wall or ceiling of the furnace using a non-oxidizing gas such as nitrogen gas as a carrier gas. A method (Japanese Patent Publication No. 2-53493) in which beko is blown obliquely from a plurality of outlets has also been proposed. However, when tapping the slag of the self-melting smelting furnace by a tap hole method, coarse carbonaceous material floats on the surface of the solution for a long time, so it seems that there is an effect of removing the beko near the surface of the solution, When the slag is constantly extracted by the overflow method, there is a large amount of coarse-grained carbonaceous material that immediately floats out of the furnace while floating on the surface of the solution, so the effect of reducing and dissolving Beco is small. Furthermore, in the method of spraying coarse carbonaceous materials such as coarse coke to the beko, it is not possible to efficiently dissolve the substance adhered to the bottom of the furnace in the solution, and coarse coke with poor reactivity is the surface of the solution of the settler. Exists for a long time, so the coating that protects the furnace wall is melted too much,
There were problems such as erosion of bricks, and a large amount of impurities such as As and Sb distributed in the mat, and measures for removing impurities in a converter or the like had to be strengthened.

[0006]

DISCLOSURE OF THE INVENTION The present invention damages the furnace wall with smoke ash and the like that drop in large amounts on a settler below the exhaust pipe of a flash smelting furnace, and the bottom deposits produced by the settler. It is to propose a method for operating a flash smelting furnace that can efficiently solve the above problems and can solve problems such as a decrease in the internal volume of the settler.

[0007]

In order to achieve the above object, the present invention provides a reaction tower, a concentrate burner provided at the top of the reaction tower, and one end of which is connected to the lower part of the reaction tower. In the method for operating a flash smelting furnace having a settler, a flue gas passage that is connected to the other end of the settler and is erected, and a boiler that is provided on the side surface of the flue gas passage, Alternatively, it is characterized in that a lance pipe is inserted into the furnace by penetrating the flue gas roof ceiling part, and at least pulverized coal and reactive gas are sprayed onto the melt in the settler or the fixed material on the furnace bottom through the lance pipe.

As the pulverized coal, those having an average particle size of 35 to 45 μm and a maximum particle size of 200 μm or less which are highly reactive and burn very easily are preferable. The charging amount is about 150 to 500 kg / hour in a commercial flash smelting furnace having a settler brick inner dimension of 7 m in width and 20 m in length. 150 kg
If it is less than / hour, the effect of dissolving smoke ash and the like that adheres to the bottom of the settler and the material stuck to the bottom of the furnace will not be sufficient, and if it exceeds 500 kg / hour, it will flow out to the boiler, and the pulverized coal will burn in the boiler and The temperature is raised too much, which is not preferable in terms of boiler management. Coke powder is also considered as a powdery carbonaceous material, but since coke powder has poor reactivity, it remains in the furnace unreacted for a long time when slag is extracted by the tap hole method, and shows the same behavior as coarse grain coke, The overflow method is not preferable because it is discharged outside the furnace before the reaction is completed.

The reaction gas is preferably air, and the total amount of blast air including the air for carrying the pulverized coal is preferably 50 to 70% of the theoretical combustion air amount of the pulverized coal. If it is less than 50%, the calorific value is insufficient and the solution is cooled, rather,
If it exceeds 70%, it is not suitable for reducing and dissolving the smoke ash containing a large amount of peroxide such as magnetite and the adhered substance on the furnace bottom.

The inner diameter of the lance pipe is 50 because of workability.
It is preferably about 80 mm. The distance from the tip of the lance pipe to the surface of the melt of the settler or the substance stuck to the furnace bottom, the wind speed at the lance pipe outlet are the amount of splash when air or pulverized coal is sprayed on the solution, and the smoke ash dropped on the settler part, etc. And it may be decided from the melting condition of the bottom fixed matter,
The former is preferably 800 to 1000 mm, and the latter is 80 to 1000 mm.
150 m / sec is preferred. If the value of the former is less than 800 mm and the value of the latter exceeds 150 m / sec, there will be too much splash and the coating on the furnace wall will be peeled off, and the coating of the furnace wall will be peeled off. If the former exceeds 1000 mm and the latter is less than 80 m / sec, the settler part will appear. It is not preferable because the smoke ash and the like that have fallen down and the adhered substances on the bottom of the furnace are not sufficiently dissolved, and the lance pipe is deteriorated by red heat due to radiant heat from the furnace wall and the like.

The boiler 14 is connected to the side surface of the smoke exhaust path 13 rising from the settler 6 of the flash smelting furnace 1 in FIG. 1, and is provided on the side surface of the smoke exhaust path 13 opposite to the boiler 14. Slope of flue gas ceiling inclined diagonally upward 1
9 is formed. The position where the lance pipe 17 is installed in the flue gas duct 13 is the flue gas duct horizontal part 18 of FIG. 2 or the flue gas duct ceiling part 19 on the opposite side of the boiler 14. Since the lance length becomes too long when the lance pipe 17 is inserted into the furnace, it is preferable that the lance pipe 17 is inserted into the furnace from the flue gas ceiling ceiling portion 19 which is as far away as possible from the side wall. ,
In a commercial flash smelting furnace with a length of 20 m, the width of the smoke exhaust 13 along the longitudinal direction of the settler 6 is about 3 m, so the boiler 1
It is preferable to insert one lance pipe at a position 1 to 2 m from the end inner wall of the settler 6 between 1 to 3 m from the side wall on the side opposite to 4.

Although only the pulverized coal and the reaction gas may be sprayed from the lance pipe 17 onto the solution in the settler 6 or the substance adhered to the furnace bottom, a sulfide concentrate, powdered copper slag, etc. are mixed with the pulverized coal and used. May be. However, if the conditions such as the spraying position and speed are not good, or if the amount of sulfide concentrate or powdered copper slag mixed is too large, the copper grade of the slag 8 discharged from the slag outlet 9 is slightly increased. It is better to adjust the mixing amount of the sulfide concentrate, powdery copper slag, etc. while observing the changes in the copper grade of the slag 8 and the copper grade of the slag 8 discharged from the outlet 16 of the electric smelting furnace 10.

[0013]

According to the present invention, the lance pipe is inserted into the furnace from the horizontal portion 18 of the flue gas ceiling or the inclined portion 19 of the flue gas ceiling, and pulverized coal having good reactivity is mixed with 50% to 70% of the theoretical combustion air amount of air. At the same time, since it is vertically sprayed onto the surface of the solution in the settler portion or the surface of the material adhered to the bottom of the furnace, the pulverized coal reacts quickly and forms a reducing atmosphere in a limited range. For this reason, the coating is performed by efficiently dissolving the smoke ash and the like that have fallen into the settler solution and the solidified material on the bottom of the furnace, and forming a reducing atmosphere in a wide range as when inserting coarse coke into the furnace. It does not cause excessive delamination and brick erosion.

The sulfide concentrate used together with the pulverized coal oxidizes and generates heat, and reduces and dissolves peroxides such as smoke ash, and the powdered copper slag has a relatively large particle size and therefore enters the solution. It collides with the substance stuck to the bottom of the furnace and exhibits an effect like shot blasting.

[0015]

【Example】

Example 1 A settler has a brick inner dimension of 7 m in width and 20 m in length, and a flue gas duct has an inner dimension of 3 m in a direction along the settler longitudinal direction.
From the center of the flue gas flue of the commercial smelting furnace of about 1.8 m from the side opposite to the boiler, the inner dimension of the flue gas duct along the longitudinal direction of the settler is 3 m. A lance pipe having an inner diameter of 50 mm was inserted into the furnace, and a settler having a slag depth of 50 to 100 mm in which the bottom fixed matter was grown was subjected to the following conditions. Distance from molten metal surface to lance tip = 1000 mm Reaction air + Pulverized coal flow air = 800 Nm ³ / hr Pulverized coal: Charge amount = 200 kg / hr Average particle size = 40 μ
m Particle size of 147 μm or more = 0.2% by weight Volatile content =
31.7% Ash content = 13.4% Fixed carbon = 52.4% Calorific value = 6920 kcal / kg Implementation period: 7 hours / day continued for 1 month.

As a result, the position closest to the position directly below the lance pipe,
From the mat outlet 11 located at a distance of 2.5 m from the smoke exhaust side end of the settler, smoke ash accumulated on the bottom of the furnace is discharged from the mat 11
The mat could not be removed because the flow path of the surrounding mat was filled, but at a rate of 1.5 tons / minute, it became possible to remove more than 40 tons per extraction. When the iron rod was inserted into the solution and investigated, the area of the furnace-bottomed deposits that had a shelf shape also decreased, and the height thereof decreased by about 300 mm.

Example 2 After the test of Example 1, the test was carried out at the same location under the following conditions. The pulverized coal used had the same properties as those used in Example 1. Distance from bath surface to tip of lance = 1000 mm Reaction air + Pulverized coal feeding air = 1000 Nm ³ / hr Pulverized coal: Charge amount = 300 kg / hr Implementation period: 7 hours / day continued for 1 month.

As a result, the height of the bottom fixed matter is about 100.
mm reduced. Furthermore, the operation of the self-melting smelting furnace was interrupted, the solution level was consciously lowered to create a situation where the adhered material on the furnace bottom was exposed above the solution level, and the condition of the adhered material on the furnace bottom from the inspection port about 18 m away Observed, the diameter was about 2000
It was found to be concave in a mortar shape of m / m, and it was confirmed that the reducing and dissolving effect of peroxide by pulverized coal was remarkable. Also, the beco that had thickly adhered to the surrounding settler furnace wall was reduced, and the pulverized coal that was not trapped in the solution was also effective in dissolving the beco that was thought to be peroxide exposed in the gas phase. Thought to be working. On the other hand, in this series of implementation, the adhered state of the smoke ash in the boiler 14 connected to the flue gas duct 13 and the change in the temperature at the outlet of the boiler 14 are within the normal fluctuation range, and pulverized coal flows into the boiler and exerts an adverse effect. I didn't.

[0019]

EFFECTS OF THE INVENTION According to the present invention, a large amount of smoke ash or the like falling on a settler under a smoke exhaust path of a flash smelting furnace and a substance adhered to the bottom of the furnace generated by the settler can be efficiently dissolved. Expands the settler internal volume, making it easier to discharge slag and mats. In addition, the splashes that are generated can also dissolve the flakes protruding from the inner wall of the furnace, which has the effect of reducing the copper content in the slag.

[Brief description of drawings]

FIG. 1 is an explanatory view of a flash smelting furnace according to the present invention.

FIG. 2 is a sectional view taken along the line EE of FIG.

FIG. 3 is an explanatory diagram of a conventional flash smelting furnace.

[Explanation of symbols]

 1 Self-smelting and smelting furnace 2 Powdered concentrate 3 Reaction gas 4 Concentrate burner 5 Reaction tower 6 Setler 7 Mat 8 Slag 9 Slag outlet 10 Electric smelting furnace 11 Matt outlet 12 High temperature exhaust gas 13 Flue gas duct 14 Boiler 15 Electrode 16 Exit 17 Lance pipe 18 Flue gas ceiling horizontal part 19 Flue gas ceiling inclined part 20 Furnace bottom fixed matter

Claims (1)

[Claims] 1. A reaction tower, a concentrate burner provided at the top of the reaction tower, a settler having one end connected to a lower part of the reaction tower, and a flue gas rising up connected to the other end of the settler. And a boiler connected to the side surface of the flue gas duct, in a method for operating a flash smelting furnace, wherein a lance pipe is passed through the flue gas duct horizontal part or the flue gas duct ceiling part into the furnace. A method for operating a flash smelting furnace, characterized in that at least pulverized coal and a reaction gas are sprayed onto the melt in the settler or the fixed material on the furnace bottom through the lance pipe.