JP3952112B2 - Operation method of flash furnace - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for operating an auto-cump flash smelting furnace used for non-ferrous metal smelting.
[0002]
[Prior art]
An auto-cump flash smelting furnace is a type of smelting furnace used for non-ferrous metal smelting.
In this flash smelting furnace, fine powdered dry raw material with silicate ore as a solvent added to sulfide concentrate is fed into the reaction tower along with auxiliary fuel and oxygen-enriched air from a concentrate burner installed at the top of the cylindrical reaction tower. And oxidative combustion reaction in the gas phase. As a product of this oxidation reaction, a mat in which valuable metals such as copper are concentrated and a slag mainly composed of iron and silicic acid are obtained as a melt and stay in the settler.
[0003]
Although the oxidation reaction is completed within an extremely short time when the dry raw material falls in the reaction tower, it is an important management point in the operation of the flash furnace to average the oxidation degree of the reactant as much as possible.
However, in the reaction tower, the dry raw material may be locally supplied in excess relative to the oxygen-enriched air, or vice versa. In the former case, oxidation is insufficient and undissolved material accumulates on the surface of the molten metal or scatters as smoke ash, oxidizes and burns in the waste heat recovery boiler to increase the gas temperature, adheres to the water pipe, and heats the boiler. The exchange rate may be reduced. In the latter case, iron in the raw material is peroxidized, leading to deterioration of the slag properties, inhibiting the separation of the product mat and slag and generating deposits in the furnace around the smoke exhaust. These cause loss of valuable metal in the slag, troubles of clogging of the mat and slag tap holes, and cause fluctuations in the molten metal temperature and valuable metal quality in the mat, and adversely affect the operation in the subsequent process.
[0004]
Further, since the solid-gas ratio of the raw material and oxygen-enriched air increases as the processing amount of the flash smelting furnace increases, it becomes more difficult to uniformly disperse the fine raw material in the reaction air. Therefore, improving the mixing and dispersibility of raw materials and reaction air and averaging the degree of oxidation of the reactants as much as possible is not only to stabilize the operation of the flash smelting furnace, but also to the throughput to a single furnace. This is an extremely important management point for increasing productivity and improving productivity.
[0005]
In order to estimate the reaction situation in this reaction tower, a method of inserting a probe from a measurement hole provided in the side wall and measuring the temperature and oxygen potential of the falling object on the reaction tower central axis, or sampling the falling object is Already widely implemented. However, it is dangerous to capture only the central axis of the furnace located directly under the concentrate burner that feeds the raw material and supplies the reaction air as the representative point of the entire furnace, and erroneously evaluates the reaction status in the reaction tower. There was a concern that would give.
[0006]
[Problems to be solved by the invention]
Therefore, it was necessary to consider measuring the temperature distribution in the reaction tower accurately. The present inventors examined a method of measuring the temperature distribution of fallen objects in the reaction tower as a criterion for determining the reaction state in the reaction tower and using the data for efficient operation. That is, when peroxidation occurs, the oxidative combustion reaction proceeds excessively, so that the temperature of the fallen object in the reaction tower increases, and conversely, when the oxidative combustion reaction is insufficient, the temperature of the fallen object decreases. In this method, the distribution of the degree of oxidation is estimated by measuring the temperature distribution. In addition, in the present invention, the temperature distribution measurement of falling objects in the reaction tower is periodically performed at a rate of once / day or more, and the daily reaction state is grasped, so that data on how to deal with changes is obtained. So that early resolution of uneven conditions can be achieved.
[0007]
That is, the present invention is (1) a measurement point on the diameter line of the reaction tower is inserted by a mobile temperature measurement device having a temperature measurement probe having a consumable thermocouple attached to the tip of the measurement hole provided on the side wall of the reaction tower. automatically moves while changing at regular intervals of the temperature distribution in the reaction tower falling objects is measured, the temperature distribution as a criteria for determining the oxidation reaction conditions of the reaction tower to determine the status of the oxidation reaction The operation method of the flash smelting furnace which averages the oxidation reaction in the reaction tower by adjusting the operation conditions according to the determination result.
[0008]
(2) The method of above (1), wherein performing the temperature distribution measurement reactor from two directions Cartesian.
It is.
[0009]
Hereinafter, the present invention will be described in detail.
FIG. 1 is a side view of an auto-cump flash smelting furnace, and FIG. 2 is a plan view.
On the side wall of the reaction tower having an inner diameter of 6.2 m × height of 6 m, in which one concentrate burner (20) is installed at the center of the top, inspection holes are installed at a total of 10 locations with different heights and positions. The temperature distribution measurement is at a level about 4.5 m below the top (arrow part of the reaction tower in FIG. 1), and is performed from four inspection holes with an inner diameter of 100 mm, which are in a positional relationship as shown in FIG. These are called A, B, C, and D holes, respectively. Even if there are four or more inspection holes, they are not excluded from the present invention.
[0010]
The concentrate burner (20) is blown with dry raw material and oxygen-enriched air, and falls while reacting in the reaction tower (1). A time of about 0.5 to 0.7 seconds elapses until reaching the position about 4.5 m below. As a result of various investigations, it can be estimated that the reaction is completed at this position.
The measurement point is not limited to the above position, but a position where the reaction is almost completed is desirable.
[0011]
The temperature is measured by attaching a consumable thermocouple (10) to the tip of the temperature measurement probe shown in FIG. 3 and inserting it into the reaction tower through each inspection hole (4-7). After insertion, hold in the reaction tower for 15 to 25 seconds, and measure the temperature of the reaction product that drops and adheres on the consumable thermocouple (10). The temperature is recorded by outputting a signal from the consumable thermocouple (10) to the chart recorder (12). At this time, for each inspection hole, the temperature of the tip position of the consumable thermocouple (10) is measured at intervals of 50 cm such that 2.5 m → 2 m →. The side fixed position may be a measurement point at which the following furnace temperature distribution can be accurately grasped. The measurement position is previously marked on the rear end side of the probe (9) by calculating back the length from the outer surface of the inspection hole furnace to the measurement point. After marking, measure the temperature and replace the consumable thermocouple in the process of inserting the probe at one measurement point → holding for 15 to 25 seconds → removing the probe. The above measurement is performed to create a temperature distribution curve as shown in FIG.
[0012]
By estimating the presence or absence of heterogeneous reaction based on this temperature distribution curve, comprehensively judging the inspection results of each place, taking measures such as changing operating conditions, etc., and maintaining a good reaction state, Continue stable operation without reducing raw material throughput.
The above temperature measurement can be performed manually using a temperature probe as shown in FIG. 3, and FIG. 5 shows a temperature measurement apparatus capable of performing this mechanically.
[0013]
The lance (18) has a double pipe structure, and is cooled when compressed air or compressed nitrogen flows from the inner pipe to the outer pipe. A holder (20) is installed at the tip of the lance (18), and a consumable thermocouple (10) is attached thereto.
The lance (18) is supported by the support roller (19), and moves on the rail back and forth by the motorized drive carriage (15) at the rear of the lance. A chain (18) is laid on the rail, and the pinion gear rotates on the chain in conjunction with the movement of the drive carriage. The number of rotations of the pinion is detected by the absolute coder (16) on the drive carriage and converted into a moving distance, and the pinion moves according to the moving distance set by the variable limit. At this time, in order to make the time of exposure to the high temperature in the furnace as short as possible, it is possible to move any measurement point from the fixed point in the furnace set by the variable limit and from the measurement point after measurement for 15 to 25 seconds. The movement to the outside is performed at a high speed (30 to 50 m / min).
[0014]
【Example】
As a result of examining the cause of deterioration in temperature distribution of the flash furnace, it became clear that the raw material was biased at the time of charging, and during the furnace repair period, the raw material charging portion of the concentrate burner (20) A modification was made to correct the drift during raw material charging.
The temperature distribution measured after the modification is shown in FIG. This temperature measurement position is the arrow portion of the reaction tower (1) shown in FIG. The operating conditions at this time were a raw material charge of 140 t / h, a total air flow of 369 Nm ³ / min, and a target mat copper content of 63%, which is almost the same as in the case of FIG. The balance is also good, and as far as this is seen, there is no drift of raw materials. During this time, the furnace condition was relatively stable, and the copper loss into the slag was 0.60%, a decrease of about 0.2% from the case of FIG. 6 shown in the comparative example.
[0015]
Thereafter, the temperature distribution in the reaction tower was used as an index of the reaction state. As a result, it is now possible to continue stable operation while raising the target copper grade of the mat to 65%, increasing the raw material charge 160 t / h and the processing capacity by about 14%.
[0016]
[Comparative example]
One of the comparative examples will be taken and described in detail below.
A typical example of the temperature distribution measurement result is shown in FIG. This temperature measurement position is also the arrow portion of the reaction tower (1) shown in FIG. The operating conditions at this time were a raw material charge of 140 t / h, a total air flow of 374 Nm ³ / min, and a target copper grade of 63% in the mat. As shown in Fig. 6, the temperature on the hole A side is in the range of approximately 1350 ° C to 1400 ° C, while on the hole C side, the point 1m to 2m from the furnace center is 1200 ° C or less. It can be seen that the temperature distribution is bad. The furnace conditions at this point were unstable, and the copper loss into the slag, which was normally 0.65 to 0.70%, deteriorated to 0.82%.
[0017]
【The invention's effect】
According to the method of the present invention, the reaction state in the reaction tower can be accurately and easily evaluated, and it becomes possible to quickly adjust the operating conditions based on the evaluation result. As a result, not only can stable operation be continued, but it is also possible to accurately cope with changes in the operation status due to the increase of raw materials. In addition, with the introduction of a mechanical temperature measuring device, when it is performed manually, measurement that takes 30 minutes to 1 hour by five people can be measured in about 20 minutes by one operator of the device.
[0018]
[Brief description of the drawings]
FIG. 1 is a side view of a flash smelting furnace.
FIG. 2 is a plan view of the flash smelting furnace.
[Fig. 3] Probe for temperature measurement [Fig. 4] Example of temperature distribution curve of reactor of the present invention [Fig. 5] Temperature distribution measuring device of reactor [Fig. 6] Temperature distribution curve of Example [Explanation of symbols]
Reaction tower raw material inlet Raw material inlet A hole B hole C hole D hole 8 Compensating lead probe consumable thermocouple sub-sleeve chart type recorder Cooling air outlet Cooling air inlet drive carriage ABSOCODER chain lance support roller 20 Concentrate burner

Claims (2)

While changing the insertion depth of the measurement points on the diameter line of the reaction tower at equal intervals by a mobile temperature measurement device with a temperature measurement probe fitted with a consumable thermocouple at the tip from the measurement hole provided on the side wall of the reaction tower automatically moves, the temperature distribution in the reaction tower falling objects is measured, the temperature distribution as a criterion for distinguishing oxidation reaction conditions of the reaction tower, to determine the status of the oxidation reaction, operation conditions by the determination result A method of operating a flash smelting furnace characterized in that the oxidation reaction in the reaction tower is averaged by adjusting The method of claim 1 for the temperature distribution measurement reactor from two directions Cartesian.

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