JP2019143209A - Operation method of metal refining furnace - Google Patents

Abstract

To provide an operation method of a metal refining furnace capable of suppressing deformation of a furnace body due to expansion of a refractory of the metal refining furnace.SOLUTION: Variation measurements 8to 8are arranged per prescribed interval around a furnace body 2, variation of whole furnace body 2 is measured periodically at prescribed timing, and control to reduce an operation temperature in a furnace 2 is conducted so that the variation of the furnace body 2 is upper limit or less when variation of at least one location is over preset upper limit, and renewal timing of the furnace body 2 is determined from remaining linear expansion coefficient of the furnace body 2 and variation limitation of a frame constituting the furnace. Thereby expansion or deformation of the furnace body 2 can be maintained in prescribed range, and further renewal of a furnace material becomes available at proper timing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for operating a metal smelting furnace, and more particularly, for example, metal smelting capable of suppressing deformation of a furnace body due to expansion of a refractory in a metal smelting furnace including a flash smelting furnace in copper refining. It relates to the operation method of the furnace.

  A metal smelting furnace in metal smelting, for example, a flash smelting furnace 100 in copper smelting, is composed of a reaction shaft 101, a setter 102 and an uptake 103, as shown in FIG. Mining burners 104, 104 are provided. Then, the concentrate is blown simultaneously with oxygen-enriched air or high-temperature hot air to cause a chemical reaction instantaneously, and is separated into mat and slag by the specific gravity difference. The flash smelting furnace 100 is characterized by a lower fuel consumption rate than other methods because it uses the heat of oxidation reaction of concentrate. Depending on the quality and composition of the raw material to be processed, the amount of heat may be insufficient with only the oxidation reaction heat, and the concentrate burners 104 and 104 may be supplemented with heavy oil or the like.

  The mat usually contains 60 to 70% of copper, and the mat is extracted from mat tap holes 105 and 105 provided in a row in the vicinity of the bottom of the flash smelting furnace 100. On the other hand, since the slag contains about 1% copper, the slag is extracted from the slag tap hole 106 provided on the lower side of the uptake 103 and sent to the smelting furnace 120 for smelting, and the copper contained in the slag. Is collected as a mat and is processed in a converter together with the mat extracted from the flash furnace 100. And electrolytic copper of higher quality is manufactured by electrolytic refining.

  The inside of a shell (can) of a copper smelting furnace including a flash smelting furnace is mainly composed of refractory bricks and irregular refractories. The refractory has a property of expanding at a high temperature during operation and contracting at a low temperature when the operation is stopped for a long time, such as during regular repair (cold repair). Such deformation of the furnace body due to the thermal expansion of the refractory leads to deterioration of the soundness of the furnace body, so it is necessary to confirm the deformation state. When the high temperature state and the low temperature state as described above are repeated, the expansion does not return to the original size even when the refractory material is contracted to a low temperature state due to the residual linear expansion, and the expansion gradually expands. Therefore, a furnace having a shorter cycle for performing cold repair has a larger deformation and displacement of the furnace frame holding the refractory due to the residual linear expansion of the refractory. Furthermore, when a specific component in the refractory, for example, MgO or CaO, comes into contact with water, a hydrate is formed and the refractory expands rapidly. In the worst case, so-called slaking occurs. Such expansion of the refractory may lead to troubles such as an increased risk of leakage due to the destruction of the arrangement of the refractory bricks at the bottom of the furnace or the generation of voids, and damage to the furnace frame.

  Therefore, conventionally, the pillar of the building where the furnace body is installed is used as a reference point, and a predetermined part of the furnace body is used as a mark, and the distance to the mark is periodically measured to monitor the expansion of the furnace body. It was done. For example, Patent Literature 1 discloses a method for measuring a furnace expansion of a coke oven.

JP-A-9-26309

  However, the conventional method has a problem that it is difficult to notice the change because the measurement point is focused on a representative portion of the furnace body as a mark. Therefore, the discovery of expansion and deformation of the furnace body is delayed, and the response such as reinforcement is delayed, which may lead to cracks and breakage of the members constituting the furnace body.

  In addition, for example, the furnace body expansion measuring method shown in Patent Document 1 merely discovers the expansion and deformation of the furnace body, and even when the expansion and deformation of the furnace body can be discovered early. It is only possible to perform repairs or the like at an appropriate time, and does not suppress or control the expansion or deformation of the furnace body itself.

  Therefore, the present invention has been made in view of such problems, and by maintaining expansion and deformation of the furnace body within an appropriate range, the risk of hot water leakage due to damage to the refractory brick array at the bottom of the furnace, An object of the present invention is to provide a method for operating a metal refining furnace capable of suppressing the occurrence of troubles such as deformation and breakage of a body frame.

  It is another object of the present invention to provide a method for operating a metal refining furnace that enables a furnace material to be updated at an appropriate timing by monitoring a furnace length change that occurs over time.

  In order to solve the above problems, the present invention according to claim 1 is a method for operating a metal refining furnace in which expansion and deformation of a furnace body are maintained within a predetermined range. Measure the displacement of each location, and if the displacement of at least one location exceeds the preset upper limit value, lower the operating temperature in the furnace so that the displacement is less than the upper limit value It is characterized by.

  In order to solve the above-mentioned problem, the present invention as claimed in claim 2 is characterized in that, in the method for operating a metal smelting furnace as claimed in claim 1, when the displacement exceeds a preset upper limit value, B. Increasing the mixing ratio of raw materials with a small calorific value for the raw materials charged into the furnace body; C. reducing the amount of raw material charged into the furnace body per hour; C. cooling the furnace body; E. Adjusting the amount of reducing material to be in-furnace environment in which self-coating can be easily formed; The operation temperature in the furnace body is lowered by either reducing the copper quality (mat grade (MG)) in the mat layer, or any combination of A to E.

  In order to solve the above-mentioned problem, the present invention described in claim 3 is the method for operating a metal refining furnace according to claim 1 or 2, wherein the displacement meters are arranged around the furnace body at predetermined intervals. The displacement of the whole furnace body is measured.

  In order to solve the above-mentioned problem, the present invention described in claim 4 is the method of operating a metal smelting furnace according to claim 3, wherein the displacement meter detects the displacement of each backstay that supports the side wall of the furnace body. It is characterized by measuring.

  In order to solve the above-mentioned problem, the present invention according to claim 5 is the method for operating a metal refining furnace according to any one of claims 1 to 4, wherein the upper limit value is obtained by displacing the furnace body. The load applied to the frame constituting the furnace body is a displacement not exceeding an elastic limit for plastically deforming the frame.

  In order to solve the above-mentioned problem, the present invention according to claim 6 is the operation method of the metal refining furnace according to any one of claims 1 to 5, wherein the furnace body is calculated based on the measured value of the displacement meter. When the remaining linear expansion coefficient exceeds a predetermined ratio, the various furnace materials forming the furnace body are updated.

  According to the method for operating a metal smelting furnace according to the present invention, it becomes possible to maintain the expansion and deformation of the furnace body within an appropriate range by enabling operation within the plastic deformation range of the furnace body frame. .

  Further, the present invention has an effect that the furnace material can be renewed at an appropriate timing by monitoring the change in the furnace length that occurs over time.

It is a top view which shows the structure of the metal smelting furnace of preferable one Embodiment for enforcing the operating method which concerns on this invention. It is AA sectional drawing of the metal smelting furnace of FIG. It is a front view of a jacket. It is a block diagram which shows the structure of the control apparatus which performs various controls based on the output of a displacement meter. It is a flowchart of one Embodiment of the operating method of the metal smelting furnace which concerns on this invention. It is front sectional drawing which shows an example of the flash smelting furnace in copper refining.

  Hereinafter, the operation method of the metal smelting furnace which concerns on this invention is demonstrated in detail based on preferable embodiment. First, before explaining the operation method of the metal smelting furnace according to the present invention, the configuration of the metal smelting furnace to which the present invention is applied will be described. FIG. 1 is a plan view showing a configuration of a metal smelting furnace of a preferred embodiment for carrying out the operating method according to the present invention, and FIG. 2 is a cross-sectional view taken along line AA of the metal smelting furnace of FIG.

[Configuration of metal smelting furnace]
The illustrated metal smelting furnace 1 is a so-called flash furnace, and generally includes a reaction shaft 3 provided on one end side, an uptake 4 provided on the other end side, a reaction shaft 3 and an uptake 4. A furnace body 2 is configured to include a setler 5 located at an intermediate portion, and the furnace body 2 is entirely formed by a shell (can body) formed of a metal material such as a steel material. And
In the furnace body 2, a plurality of backstays 2 a and 2 a are arranged at a predetermined interval so as to surround the periphery as reinforcing materials for ensuring necessary strength.

  The reaction shaft 3 has a substantially cylindrical shape, and a plurality of concentrate burners 6 and 6 are disposed on the reaction shaft 3. A preheating air inlet 7 is provided adjacent to the concentrate burners 6 and 6. The setler 5 is formed by connecting a plurality of water cooling jackets 30 as shown in FIG. The water cooling jacket 30 includes a plurality of cooling pipes 32 and 32 for circulating cooling water therein, and water supply ports 33 and 33 for supplying cooling water are provided on one end sides of the cooling pipes 32 and 32, respectively. In addition, drain ports 34 for discharging cooling water are provided on the other end side. A plurality of ribs (not shown) are formed on the inner surface of the furnace, and fire bricks (not shown) are stacked on the ribs. The uptake 4 recovers waste heat by guiding the internal exhaust gas to a waste heat boiler, and the cooled exhaust gas is sent to a sulfuric acid factory.

Around the furnace body 2, the required number (42 in the present embodiment) of displacement gauges 8 (hereinafter referred to as “displacement gauges 8 ₋₁ to 8 ₋₄₂ ”) surrounds the furnace body 2 at predetermined intervals. Say). These displacement gauges 8 measure the overall displacement of the furnace body 2. In the present embodiment, the displacement meters 8 ₋₁ to 8 ₋₄₂ are disposed to face the 42 backstays 2 a disposed in the furnace body 2 at the furnace bottom level where the expansion is large. Note that the number of displacement meters 8, 8 is not limited to 42, and is appropriately determined according to the shape, size, etc. of the furnace body 2. Further, the displacement measurement is not limited to the backstay 2a, and an appropriate position of the furnace body 2 can be used as a mark.

The displacement meters 8 ₋₁ to 8 ₋₄₂ are optical or physical sensors that measure the displacement (expansion) of the furnace body 2, and output an electrical signal obtained by converting the measured displacement amount of the furnace body 2 into a length. To do. Examples of the displacement meters 8 _-1 to 8 _-42 include a non-contact method such as a laser focus method, an ultrasonic method, and a triangulation, a contact method using a differential transformer, and the like.

FIG. 4 is a block diagram showing the configuration of a control device that performs various controls based on the output of the displacement meter. The control device 10 includes a CPU, a memory, and the like, and includes a program that takes in the measurement values obtained by the displacement meters 8 _-1 to _8-42 at regular intervals and executes the flow illustrated in FIG. 5 based on the measurement values. A calculation unit 11 is provided. That is, the control unit 10 monitors whether or not the displacement (expansion) of the furnace body 2 measured by the displacement meters 8 _-1 to _8-42 is within a preset upper limit range. When the displacement (expansion) exceeds a preset upper limit of displacement, control is performed to lower the operating temperature so that the displacement (expansion) is less than or equal to the upper limit value. And in order to perform control which lowers operating temperature, the following control systems are provided. That is, the control device 10 includes a raw material mixing control unit 12 that increases the mixing ratio of a raw material with a small calorific value, for example, iron oxide slag, with respect to the raw material charged into the furnace body 2 based on a command from the calculating unit 11, and a calculating unit. 11, a charging amount control unit 13 that controls the charging amount per time of concentrate based on a command from 11, a cooling control unit 14 that cools the furnace body 2 based on a command from the calculation unit 11, and a calculation unit 11. Is provided with a reducing material charging control unit 15 for controlling the amount of reducing material charged into the furnace.

  Here, the upper limit value is a displacement in which the load applied to the frame constituting the furnace body 2 by the displacement of the furnace body 2, for example, the backstay 2a does not exceed the elastic limit for plastically deforming the backstay 2a, preferably elastic A displacement having a certain margin with respect to the limit, for example, a displacement having a margin of 10%. In other words, since the refractory expands when heated and contracts when the temperature decreases, the displacement is smaller than when the operation is stopped, but the refractory does not return completely due to the characteristics of the refractory, and heating and cooling are repeated. Over time, the displacement during heating increases, and the displacement gradually increases even when cooled. If the load applied to the frame constituting the furnace body 2, for example, the backstay 2a, exceeds the elastic limit for plastic deformation of the backstay 2a due to the displacement of the furnace body 2, the operating temperature is lowered. This is because the furnace body 2 remains in a deformed state.

  As control for lowering the operating temperature, the raw material mixing control unit 12 increases the amount of iron oxide slag supplied to the concentrate in the raw material mixing device 22 for mixing the concentrate and the raw material having a small calorific value, for example, iron oxide slag, The charging amount control unit 13 controls the operation of the concentrate charging device 23 for charging the concentrate to reduce the charging amount per hour, and the cooling control unit 14 cools the cooling water supplied into the water cooling jacket 30. Cooling of the bottom of the furnace is promoted by increasing the amount and / or flow rate of water, and the reducing material charging control unit 15 adjusts the amount of reducing material charged into the furnace from the reducing material charging device 24. In addition, the cooling of the bottom of the furnace is performed by controlling the output of a fan (not shown) that blows cool air toward the bottom of the furnace by the cooling control unit 14 to cool the bottom of the furnace or to reduce the oxygen concentration of the reaction gas supplied into the furnace. It is also possible to adjust the furnace temperature. The reducing material is introduced from a plurality of locations in the furnace body. For example, the amount of reducing material introduced into a high-temperature area is reduced or stopped to form on the furnace inner wall of the area. Since the thickness of the magnetite-based self-coating is increased, the furnace temperature in the area can be partially reduced. Further, the management can be performed based on the quality of the desired metal in the mat layer in which the desired metal is concentrated, that is, the mat grade (MG). For example, it is possible to adjust the heat generation amount to be decreased by lowering the MG and the operating temperature in the furnace is lowered.

[Operation method of metal smelting furnace]
Next, an embodiment of a method for operating a metal refining furnace according to the present invention will be described. FIG. 5 is a flowchart of an embodiment of a method for operating a metal smelting furnace according to the present invention. First, when the operation is started, displacement associated with local expansion is measured for each backstay 2a, 2a of the furnace body 2 corresponding to each displacement meter 8 _-1 to 8 _-42 at predetermined time intervals (steps). S <b> 1), and the measurement value is taken into the calculation unit 11. The computing unit 11 monitors whether or not at least one of the displacement meters 8 ₋₁ to 8 ₋₄₂ is within the range of the preset upper limit value of displacement. When the calculating unit 11 of the control device 10 determines that at least one displacement gauge ₈ -1 _{8 -42} exceeds the upper limit value: (step S2 Yes) is, (A) a raw material mixing control unit 12 Controls the operation of the raw material mixing device 22 and increases the mixing ratio of the raw material with a small calorific value for the raw material charged into the furnace body 2. (B) The charging amount control unit 13 operates the concentrate charging device 23. (C) The cooling control unit 15 lowers the amount of raw material charged into the furnace body 2 per hour (for example, from 210 t / h to 170 t / h). The temperature of the furnace body 2 is lowered by adjusting the amount of water. (D) The reducing material charging control unit 15 controls the operation of the reducing material charging device 24 to reduce or stop the amount of reducing material charged into the furnace body 2. Promotes self-coating on the inner wall of the furnace, The operating temperature is lowered by any one of (E) lowering the MG of the desired metal in the mat layer or any combination of the above (A) to (E) (step S3) Control is performed so as to be below the upper limit. The reducing material charging control unit 15 adjusts the charging amount only for the reducing material charging device 24 arranged in a high temperature area among the plurality of reducing material charging devices 24 to partially increase the self-coating thickness. Can be controlled.

  Since the displacement of the furnace body 2 can be maintained in an appropriate range by such control, the change in the furnace length that occurs over time can be monitored. As a result, the operation within the range of plastic deformation of the furnace body 2, that is, the furnace body 2 It becomes possible to manage the constituent members without breaking them, and it is possible to take measures such as reinforcement before the hot water leaks or the furnace body constituent members break. And it becomes possible to aim at the risk reduction of a hot water leak, and the extension of a furnace body lifetime. In addition, when local expansion is observed, it is possible to reduce the risk of hot water leakage in that portion by enhancing cooling in the vicinity of the area.

When the measured values of the displacement meters 8 ₋₁ to 8 ₋₄₂ are equal to or lower than the upper limit values by the control described above (step S4: Yes), the control unit 10 includes the raw material mixing control unit 12 and the charging amount control unit. 13. A command is sent to the cooling control unit 14 so as to perform a preset normal operation, and the operation is continued within an appropriate range where the operation temperature is not more than the upper limit value (step S5). On the other hand, when the measured values of the displacement meters 8 _-1 to _8-42 are not yet below the upper limit values (step S4: No), the process of step S3 is continued.

By continuing the operation as described above, when the residual linear expansion coefficient of the furnace body 2 calculated by the measured values of the displacement meters 8 _-1 to _8-42 exceeds a predetermined ratio, the furnace body 2 is Renew various furnace materials to be formed. Here, as described above, if the load applied to the backstay 2a exceeds the elastic limit for plastically deforming the backstay 2a, the displacement does not return to the original even if the furnace body 2 is cooled. It is preferable to set the residual linear expansion coefficient, which serves as a standard for renewal of various furnace materials, to a ratio that does not exceed at least the elastic limit for plastic deformation of the backstay 2a.

As described above, according to the operation method of the metal smelting furnace according to the present embodiment, the displacement (expansion) of the furnace body 2, for example, the side walls of the furnace body 2 are supported by the displacement meters 8 ₋₁ to 8 _-42 . When the displacement of the backstay 2a is measured and at least one displacement exceeds a preset upper limit value, the controller 10 operates the furnace body 2 so that the displacement becomes equal to or less than the upper limit value. Since the operation temperature is lowered by decreasing the temperature or increasing the coating thickness in the area exceeding the upper limit, the expansion and deformation of the furnace body 2 can be maintained within an appropriate range. It becomes possible to prevent the arrangement of the firebrick at the bottom of the furnace due to thermal expansion, the generation of voids, and the like.

Further, according to the operating method of the metal refining furnace according to the present embodiment, it was decided to measure the entire displacement of the furnace body 2 by the displacement gauge 8 _-1 8 _-42 at predetermined intervals around the furnace body 2 Therefore, the furnace length change can be monitored at any time, and the furnace material can be updated at an appropriate timing.

  Furthermore, according to the operation method of the metal smelting furnace according to the present embodiment, by updating the various furnace materials forming the furnace body when the residual linear expansion coefficient of the furnace body exceeds a predetermined ratio, Since renewal can be performed before the end, there is an effect that operation stoppage can be shortened and repair costs can be reduced.

[Other embodiments]
The present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from or changing the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Metal smelting furnace 2 Furnace body 2a Backstay 3 Reaction shaft 4 Uptake 5 Settler 6 Concentration burner 7 Preheating air inlet 8 Displacement meter 10 Control apparatus 11 Calculation part 12 Raw material mixing control part 13 Charge amount control part 14 Cooling control 15 Reducing material charging control unit 22 Raw material mixing device 23 Concentrate charging device 24 Reducing material charging device 30 Water cooling jacket

Claims (6)

In the method of operating a metal refining furnace that maintains expansion and deformation of the furnace body within a predetermined range,
When a plurality of displacement gauges measure a plurality of displacements at a predetermined location of the furnace body and at least one displacement exceeds a preset upper limit value, the displacement is equal to or less than the upper limit value. A method for operating a metal refining furnace, characterized in that the operating temperature in the furnace body is lowered. In the operation method of the metal smelting furnace according to claim 1,
When the displacement exceeds the preset upper limit value,
A. Increasing the mixing ratio of raw materials with small calorific values for the raw materials charged into the furnace body;
B. Reducing the amount of raw material charged into the furnace body per hour;
C. Cooling the furnace body;
D. By adjusting the amount of reducing material input, make the furnace environment easy to form a self-coating,
E. Lowering the copper grade (mat grade (MG)) in the mat layer,
A method for operating a metal refining furnace, wherein the operating temperature in the furnace body is lowered by any one of the above or a combination of any of A to E. In the operation method of the metal smelting furnace according to claim 1 or 2,
The displacement meter is arranged at predetermined intervals around the furnace body, and measures the total displacement of the furnace body. In the operation method of the metal smelting furnace according to claim 3,
The method for operating a metal refining furnace, wherein the displacement meter measures a displacement of each backstay that supports a side wall of the furnace body. In the operation method of the metal smelting furnace according to any one of claims 1 to 4,
The upper limit value is a displacement in which a load applied to a frame constituting the furnace body due to the displacement of the furnace body does not exceed an elastic limit for plastically deforming the frame. Method. In the operation method of the metal smelting furnace according to any one of claims 1 to 5,
An operation of a metal smelting furnace characterized in that when a residual linear expansion coefficient of the furnace body calculated by a measured value of the displacement meter exceeds a predetermined ratio, various furnace materials forming the furnace body are updated. Method.

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