JP7167573B2 - Supply amount control method - Google Patents

Description

The present invention relates to a supply amount control method. More particularly, it relates to a method of controlling the amount of supply of concentrate such as copper concentrate to a concentrate burner of a flash furnace.

In the dry copper smelting process, the copper concentrate (hereinafter sometimes referred to as dry ore) dried in a flash furnace is oxidized by burning it in a concentrate burner to remove some of the sulfur and iron and produce copper to produce a mat containing This matte is fed to a converter where high purity blister copper is produced.

In order to stably produce blister copper in a converter, it is necessary to maintain a stable copper grade in the matte in the flash furnace. It is important to let This is because the concentrate burner is supplied with a constant amount of oxygen that is used to burn the dry ore, so if the amount of dry ore supplied to the concentrate burner fluctuates, the amount of oxygen supplied to the concentrate burner will change. and the amount of dry ore would be out of balance. As a result, unburned dry ore is generated and copper is in a peroxidized state, so that proper matte is not formed, the amount of unrecoverable copper increases, and operational troubles occur in the copper smelting process. There is a possibility that

The dry ore supplied to the concentrate burner of the flash furnace is temporarily stored in a storage container such as a hopper, and then conveyed to the concentrate burner of the flash furnace by a conveying device such as a screw conveyor. However, since the condition of the dry ore in the storage vessel fluctuates, the amount of dry ore transferred by the transfer device to the concentrate burner of the flash furnace fluctuates. Therefore, in order to stabilize the amount of dry ore supplied to the concentrate burner, the amount of dry ore supplied to the concentrate burner (mass flow rate) is grasped and the amount of dry ore conveyed by the conveying device is adjusted. becomes necessary.

As a method for measuring the mass flow rate of powder such as dry ore transported by a transport device, there is an impact flow meter (for example, Patent Document 1).
The impact-type flowmeter is provided with a detection plate against which falling powder collides, and a load detector measures the impact force of the powder applied to the detection plate to calculate the mass flow rate of the powder. Specifically, the amount of displacement (the amount of rotation and the amount of parallel movement) of the detection plate when the powder collides is detected by a load detector, and the flow rate of the powder is calculated based on the amount of displacement.

JP-A-57-189013

However, in a flash furnace concentrate burner, hot air may flow back from the concentrate burner due to combustion of the concentrate burner. Since the hot air flows in the direction opposite to the direction in which the dry ore collides with the detection plate, the displacement of the dry ore when it collides with the detection plate is suppressed by this hot air, and the impact force of the dry ore is calculated to be smaller than it actually is. There is a possibility that it will be done. In other words, there is a possibility that the flow rate of dry ore is calculated to be smaller than the actual amount. Then, when the flow rate of dry ore is adjusted based on the calculated flow rate of dry ore, the balance between the amount of oxygen and the amount of dry ore may be further disturbed. Therefore, at present, the amount of dry ore transported to the flash furnace is not measured using an impact flow meter, and the transport device based on the flow rate of dry ore measured using an impact flow meter. is not controlled.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a method for controlling the amount of concentrate that can be stably supplied to the concentrate burner of a flash furnace by a conveying device.

A supply amount control method of the first invention is a method of adjusting the amount of concentrate supplied from a storage device in which concentrate is stored to a concentrate burner of a flash furnace using a conveying device, wherein the storage device automatically An impact-type powder mass flow meter is installed in the flow path for conveying the concentrate to the concentrate burner of the blast furnace, and the impact-type powder mass flow meter communicates with the flow path and drops the concentrate. A detection member having a body portion having a flow path, and a through space penetrating between a collision surface on which the concentrate collides and a back surface located on the opposite side of the collision surface, which are arranged in the drop flow path of the body portion. and a flow rate calculation unit for calculating the mass flow rate of the concentrate based on the amount of movement of the detection member, wherein the mass flow rate detected by the impact powder mass flow meter deviates from the reference value. maintains the amount of ore conveyed until a certain period of time has elapsed, and after a certain period of time has elapsed in which the mass flow rate detected by the impact powder mass flow meter has increased from the reference value, the amount of ore conveyed by the conveying device is reduced. and when the rate of increase in the mass flow rate detected by the impact type powder mass flow meter exceeds a predetermined rate of increase, the transport of the concentrate by the transport device is stopped.
A second aspect of the present invention provides a method for controlling the amount of supply, in the first aspect, wherein the impact-type powder mass flow meter is arranged immediately before the concentrate burner of the flash furnace.

According to the first invention, since the conveying device is controlled based on the mass flow rate of the concentrate measured by the impact powder mass flow meter, the mass flow rate of the concentrate can be appropriately controlled. In addition, when the mass flow rate fluctuates abruptly, the supply of the concentrate by the conveying device is stopped, so that it is possible to prevent a drop in the copper recovery rate and operational troubles. Moreover, it is possible to prevent problems such as a decrease in the integrated value of the mass flow rate of the concentrate.
According to the second invention , since the mass flow rate of the concentrate supplied to the concentrate burner of the flash furnace can be grasped more accurately, the conveying state of the concentrate can be brought into a more appropriate state.

1 is a schematic explanatory diagram of a constant supply device 1 used in the supply amount control method of the present embodiment; FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory diagram of an impact-type powder mass flowmeter 10 used in a constant supply device 1 used in the supply amount control method of the present embodiment, (A) is an external perspective view, and (B) is an internal It is explanatory drawing of a structure. 4 is a diagram showing an example of a detection member 13 employed in the impact powder mass flowmeter 10. FIG. It is a graph showing the result of controlling the amount of powder supplied to the self-melting furnace by the method of controlling the amount of supply of the present invention, showing the relationship between the rotation speed (SC rotation speed) of the screw conveyor and the load of the impact type powder mass flow meter. It is a graph which shows a time change.

The supply amount control method of the present embodiment is a method for controlling the supply amount of concentrate such as copper concentrate to the concentrate burner of the flash furnace, and the supply amount of the concentrate supplied to the concentrate burner fluctuates. It is characterized by being able to suppress

The concentrate for which the supply amount to be supplied to the concentrate burner of the flash furnace is adjusted by the supply amount control method of the present embodiment is not limited to the copper concentrate. For example, when supplying silica sand, smoke ash, or the like to a concentrate burner of a flash furnace, the supply amount control method of the present embodiment can be employed.

<Quantitative supply device 1>
First, before explaining the supply amount control method of the present embodiment, the outline of the fixed amount supply device 1 (hereinafter sometimes simply referred to as the fixed amount supply apparatus 1) used in the supply amount control method of the present embodiment will be explained.

As shown in FIG. 1, the fixed quantity supply device 1 includes a conveying device 2 that cuts out and conveys the concentrate M stored in a storage device H such as a hopper. The conveying device 2 is not particularly limited as long as it has a function of continuously conveying the concentrate M supplied from the storage device H by a constant amount. For the conveying device 2, for example, a known powder conveying device such as a screw conveyor, a belt conveyor, or a chain conveyor can be used. A screw conveyor is preferable as the conveying device 2 in consideration of the scattering of the concentrate M to the surroundings and the ease of controlling the conveying amount. Below, the case where the conveying device 2 is a screw conveyor will be described.

As shown in FIG. 1, the conveying device 2 is electrically connected to a controller 20 for controlling its operation. This control unit 20 has a function of adjusting the operation of the conveying device 2 , that is, the mass flow rate of the concentrate M conveyed by the conveying device 2 . For example, if the conveying device 2 is a screw conveyor, the control unit 20 has a function of adjusting the mass flow rate of the concentrate M by controlling the rotation speed and operation timing of the motor that operates the screw conveyor. .

As shown in FIG. 1, the upper end of the supply pipe 3 is connected to the end (the right end in FIG. 1) from which the concentrate M is discharged in the conveying device 2 . The supply pipe 3 and the powder discharge port of the conveying device 2 are airtightly connected to prevent the concentrate M from scattering outside. The supply pipe 3 is arranged substantially vertically, and the concentrate M supplied from the upper end of the supply pipe 3 moves toward the lower end in the supply pipe 3 due to gravity.

In addition, the supply pipe 3 does not necessarily have to be arranged vertically as long as the concentrate M can move smoothly from the upper end to the lower end. good.

An impact type powder mass flow meter 10 is provided at the lower end of the supply pipe 3 . This impact type powder mass flowmeter 10 is a device for measuring the mass flow rate of the concentrate M supplied from the supply pipe 3 . As shown in FIG. 2(A), the main body 11 of this impact type powder mass flowmeter 10 has its upper end airtightly connected to the lower end of the supply pipe 3 . The body portion 11 is provided with a drop channel 11h for allowing the concentrate M to freely drop inside (see FIG. 2(B)). The body portion 11 is provided with a detection portion 12 for measuring the mass flow rate of the concentrate M dropping through the drop passage 11h. The detection unit 12 includes a flow rate calculation unit 15 having a calculation unit 17 that calculates the mass flow rate and transmits the calculated mass flow rate of the concentrate M to the control unit 20 described above.

The upper end of the discharge pipe 4 is airtightly connected to the lower end of the body portion 11 of the impact powder mass flowmeter 10 . The lower end of the discharge pipe 4 is air-tightly connected to the concentrate supply port of the concentrate burner B of the flash furnace F so as to prevent the concentrate M from scattering outside. The discharge pipe 4 is arranged substantially vertically, and the concentrate M supplied from the upper end of the discharge pipe 4 moves toward the lower end, that is, toward the concentrate supply port of the concentrate burner B by gravity. It is designed to

The discharge pipe 4 does not necessarily have to be arranged vertically as long as the concentrate M can be smoothly moved from the upper end to the lower end, and the discharge pipe 4 may be arranged so as to be inclined with respect to the vertical direction. good.

<Supply amount control method of the present embodiment>
In the supply amount control method of the present embodiment, since the quantitative supply device 1 described above has the structure described above, based on the information on the mass flow rate of the concentrate M measured by the impact powder mass flow meter 10, can control the supply amount of the concentrate M to the concentrate burner B of the flash furnace F.
The supply amount control method of this embodiment will be described below.

First, when the information on the mass flow rate of the concentrate M measured from the impact powder mass flowmeter 10 is supplied to the control unit 20, the control unit 20 determines that if the mass flow rate of the concentrate M is within a predetermined range, , controls the operation of the conveying device 2 so as to maintain the current state.

On the other hand, when the measured mass flow rate of the concentrate M exceeds a certain range (reference value), the control unit 20 adjusts the operation of the conveying device 2 . For example, when the mass flow rate of the concentrate M exceeds a predetermined value, the controller 20 adjusts the operation of the conveying device 2 to reduce the conveyed amount of the concentrate M. If the conveying device 2 is a screw conveyor, the number of revolutions thereof is lowered to reduce the amount of the concentrate M conveyed. As a result, it is possible to prevent problems such as an increase in the melt level due to an increase in the mass flow rate of the concentrate M supplied to the concentrate burner B of the flash furnace F.

Conversely, when the mass flow rate of the concentrate M falls below the predetermined value, the controller 20 adjusts the operation of the conveying device 2 to increase the conveyed amount of the concentrate M. If the conveying device 2 is a screw conveyor, the rotational speed is increased to increase the conveying amount of the concentrate M. Also in this case, problems such as peroxidation of the concentrate due to a decrease in the mass flow rate of the concentrate M supplied to the concentrate burner B of the flash furnace F can be prevented.

As described above, when the measured mass flow rate of the concentrate M exceeds the reference value, the control unit 20 causes the transport device 2 to operate as soon as the measured mass flow rate of the concentrate M deviates from the predetermined value. may be controlled. However, if the mass flow rate of the concentrate M deviates from a predetermined value (abnormal state) within a certain period of time, the current state is maintained, and if the abnormal state exceeds a certain period of time, the transport device 2 is operated. You may make it adjust. Then, even if the mass flow rate of the concentrate M increases, the increased mass flow rate of the concentrate M is maintained for a certain period of time, so the mass flow rate of the concentrate M does not suddenly decrease. Therefore, problems such as a decrease in the integrated value of the mass flow rate of the concentrate M supplied to the concentrate burner B of the flash furnace F can be prevented from occurring.

Moreover, when the rate of increase in the mass flow rate of the concentrate M exceeds a predetermined rate of increase, the control unit 20 may stop the transport of the concentrate M by the transport device 2 . When such a sudden change occurs, even if an attempt is made to adjust the mass flow rate of the concentrate M by operating the conveying device 2 (for example, the number of revolutions of the screw conveyor, etc.), it may not be possible to sufficiently control it. On the other hand, if the transport of the concentrate M by the transport device 2 is stopped, the flow resistance given to the concentrate can be increased. Become. Therefore, when the mass flow rate of the concentrate M fluctuates abruptly, if the transport of the concentrate M by the transport device 2 is stopped, the flash furnace F caused by the rapid increase in the mass flow rate of the concentrate M Fluctuations in the combustion state of the concentrate M in the concentrate burner B can be suppressed as much as possible.

<Regarding impact type powder mass flowmeter 10>
As described above, in adopting the supply amount control method of the present embodiment to stabilize the mass flow rate of the concentrate M supplied to the concentrate burner B of the flash furnace F, it is necessary to accurately control the mass flow rate of the concentrate M Understanding is important.

In the method of controlling the amount of supply of the present embodiment, the device for measuring the mass flow rate of the concentrate M is not particularly limited as long as it can stably grasp the fluctuation of the mass flow rate of the concentrate M. However, by adopting the impact type powder mass flowmeter 10 having the following structure, the mass flow rate of the concentrate M supplied to the concentrate burner B of the flash furnace F can be stably measured.

As shown in FIG. 2, the impact-type powder mass flowmeter 10 includes a body portion 11 and a detection portion 12 that measures the mass flow rate of the concentrate M falling in the drop channel 11h of the body portion 11. ing.

As shown in FIG. 2, the body part 11 is a container having a hollow space inside. As described above, the lower end of the supply pipe 3 and the upper end of the discharge pipe 4 are airtightly connected to the body portion 11, and the supply pipe 3 and the discharge pipe 4 are communicated with the space inside the body portion 11. there is The supply pipe 3 and the discharge pipe 4 are connected to the body portion 11 such that the central axes CL3 and CL4 of the openings connected to the body portion 11 are vertical and the central axes CL3 and CL4 are aligned.

Therefore, the concentrate M supplied from the supply pipe 3 falls into the discharge pipe 4 through the space inside the main body 11 . At this time, the space inside the main body portion 11 through which the concentrate M passes becomes the drop flow path referred to in the claims. In FIG. 2, a virtual cylinder indicated by a dotted line connecting the supply pipe 3 and the discharge pipe 4 is the drop flow path 11h.

2 shows the case where the inner diameters of the supply pipe 3 and the discharge pipe 4 are the same, a virtual cylinder connecting the supply pipe 3 and the discharge pipe 4 so as to be continuous becomes the drop flow path 11h. On the other hand, when the inner diameters of the supply pipe 3 and the discharge pipe 4 are different, a virtual cylinder obtained by extending the supply pipe 3 becomes the drop flow path 11h.

As shown in FIG. 2 , a support frame 14 for the detection section 12 is provided inside the main body section 11 . The support frame 14 has its base end portion (the right end portion in FIG. 2(B)) fixed to the main body portion 11 .

A detection member 13 is provided at the tip of the support frame 14 . The detection member 13 is a plate-like member, and a plurality of sensors penetrating between its surface (upper surface in FIG. 2(B), hereinafter referred to as collision surface 13a) and its rear surface 13b (lower surface in FIG. 2(B)). is provided with a through space 13h (see FIG. 3). The detection member 13 is provided so that the collision surface 13a is horizontal when no force is applied to the collision surface 13a or the rear surface 13b. In other words, the detection member 13 is provided so that the collision surface 13a is perpendicular to the central axes CL3 and CL4 of the supply pipe 3 and the discharge pipe 4 when no force is applied to the collision surface 13a and the back surface 13b. . Moreover, the detection member 13 is formed so that the area surrounded by the outer edge 13e (outer edge area) is larger than the horizontal cross-sectional area (flow path area) of the drop flow path 11h in the above posture ( See Figure 3).

Further, the support frame 14 is connected with the measuring section 16 of the flow rate calculating section 15 . The weighing unit 16 detects the impact applied to the detection member 13, that is, the impact generated when the concentrate M falling down the drop passage 11h collides with the detection member 13. As shown in FIG. The weighing unit 16 is, for example, a load cell, a strain gauge, or the like, but is not particularly limited as long as it can detect the impact. Further, the weighing unit 16 has a function of outputting an impact applied to the detecting member 13 as an electric signal.

The measuring section 16 is electrically connected to the calculation section 17 of the flow rate calculation section 15 . This calculation unit 17 has a function of calculating the mass flow rate of the concentrate M based on the impact detected by the weighing unit 16 . The calculation unit 17 has a function of calculating the mass flow rate of the concentrate M based on the output signal transmitted from the weighing unit 16 using, for example, a relational expression obtained from the known flow rate and the shock value. Moreover, the calculation unit 17 has a function of transmitting the calculated mass flow rate of the concentrate M to the control unit 20 as described above.

If the impact type powder mass flowmeter 10 as described above is used, even if hot air or the like generated by combustion from the concentrate burner B of the flash furnace F is blown into the discharge pipe 4 and wind pressure is applied to the detection member 13, the wind pressure will be reduced. can reduce the impact. That is, since the wind pressure can be released by the penetration space 13h of the detection member 13, the mass flow rate of the concentrate M can be measured while suppressing the influence of the wind pressure. Then, the precision of the mass flow rate of the concentrate M measured based on the impact applied to the detection member 13 can be improved.

Therefore, if the control unit 20 controls the operation of the conveying device 2 based on the mass flow rate of the concentrate M measured by the impact-type powder mass flow meter 10 as described above, the concentrate burner B of the flash furnace F Concentrate can be stably supplied.

In addition, in the flow path through which the concentrate M is conveyed, the position where the above-described impact-type powder mass flow meter 10 is installed is not particularly limited. If it is arranged immediately before the concentrate burner B of the flash furnace F as described above, the mass flow rate of the concentrate M supplied to the concentrate burner B of the flash furnace F can be grasped more accurately. The advantage is that the state can be brought to a more appropriate state.

<Regarding the detection member 13>
As described above, the detection member 13 is formed so that the area of the outer edge is larger than the area of the flow path (see FIG. 3). However, as long as the mass flow rate of the concentrate M can be measured with a certain degree of accuracy, the outer edge area does not necessarily have to be larger than the channel area. However, if the outer edge area is made larger than the channel area, even if the concentrate M falls in a biased position when dropping through the drop channel 11h, the concentrate M will not collide with the detection member 13. can be done. Therefore, the mass flow rate of the concentrate M based on the impact applied to the detection member 13 can be accurately measured regardless of the drop state of the concentrate M when dropping through the drop passage 11h.

In addition, the shape, size, number, etc. of the through space 13h formed in the detection member 13 are not particularly limited, and even if wind pressure is applied to the back surface 13b of the detection member 13, the measurement of the mass flow rate of the concentrate M is affected. It is sufficient if the wind pressure can be reduced to the extent that it does not occur. For example, as shown in FIG. 3A, a plurality of through spaces 13h having elongated openings may be provided as the detection member 13, or a large number of through holes having a grid-like frame and serving as the through spaces 13h may be provided for detection. A member 13 may be used.

Further, by providing a large number of through spaces 13h, the resistance caused by the wind pressure applied to the back surface 13b of the detection member 13 is reduced, while the amount of the concentrate M colliding with the detection member 13 is reduced. In other words, if the opening area of the through space 13h is increased, the measurement accuracy of the mass flow rate of the concentrate M based on the impact applied to the detection member 13 may decrease. Therefore, in order to reduce the resistance caused by the wind pressure applied to the back surface 13b of the detection member 13 and prevent a decrease in the measurement accuracy of the mass flow rate of the concentrate M, the total area of the opening areas of all the through spaces 13h is , is preferably adjusted to about 30 to 70% of the outer edge area.

It should be noted that resistance due to wind pressure applied to the back surface 13b of the detection member 13 can be reduced when the opening areas of the through spaces 13h are large. Therefore, it is desirable to increase the opening area of each through space 13h while keeping the total area within the above range.

(Flow rate calculator 15)
For the measuring unit 16 of the flow rate calculating unit 15, one that detects deformation or movement of the support frame 14 may be used. In other words, when the support frame 14 swings or bends about its base end due to the impact force from the concentrate M applied to the detection member 13, the amount of bending or the amount of movement is determined. may be measured. For example, a load cell or the like is used as the weighing unit 16, and the calculating unit 17 calculates the impact force applied from the concentrate M to the detection member 13 based on the amount of displacement of the weighing unit 16. The mass flow rate may be calculated by the calculator 17 .

Also, in the above example, the flow rate calculator 15 has the calculator 17 , but the calculator 17 does not necessarily have to be provided in the impact powder mass flowmeter 10 . That is, the signal from the measuring section 16 of the flow rate calculating section 15 may be directly transmitted to the control section 20 . In this case, the controller 20 may be provided with a function of calculating the mass flow rate of the concentrate M based on the signal from the weighing unit 16 .

Experiments confirmed the effectiveness of controlling the amount of powder supplied by the method of controlling the amount of supply of the present invention.
In the experiment, in a facility where copper concentrate is cut out from a storage tank with a screw conveyor installed at the bottom and supplied to a flash furnace, an impact type powder mass is placed between the screw conveyor and the inspection port of the flash furnace. A flow meter was installed. Then, the operation of the screw conveyor was controlled based on the impact force measured by the impact-type powder mass flow meter to adjust the amount of powder supplied to the self-melting furnace.

The amount of powder supplied from the screw conveyor to the self-melting furnace was adjusted by the rotation speed of the screw conveyor.

The results are shown in FIG.
As shown in FIG. 4, the load value measured by the impact-type powder mass flowmeter increases sharply even when the rotation of the screw conveyor is not changed (see arrow A in FIG. 4). In other words, it can be confirmed that the increase in the amount of copper concentrate supplied to the flash furnace can be detected by the impact powder mass flowmeter.

As shown in FIG. 4, the rotation speed of the screw conveyor sharply decreases immediately after the load value measured by the impact powder mass flowmeter increases. That is, since the load value measured by the impact type powder mass flowmeter increased sharply, it can be confirmed that the rotational speed of the screw conveyor decreased sharply (see arrow B in FIG. 4).

If the speed of the screw conveyor is kept low for a certain period of time after the speed of rotation of the screw conveyor suddenly decreases, the load value measured by the impact powder mass flow meter will decrease and return to the value before the sudden increase. It's becoming

Then, when the conveyed amount of the copper concentrate supplied to the flash furnace decreases from the original state, the copper concentrate supplied to the flash furnace is increased by increasing the rotation speed of the screw conveyor (see arrow C in FIG. 4). It can be confirmed that the ore transportation amount has returned to the original stable transportation amount.

As described above, if the rotation speed of the screw conveyor is reduced based on the load value measured by the impact powder mass flow meter, even if the amount of copper concentrate supplied to the flash furnace fluctuates greatly, It was confirmed that it was possible to confirm that the conveyance amount was restored to an appropriate amount. Even if the amount of copper concentrate supplied to the flash furnace increases rapidly, the amount of copper concentrate conveyed can be restored to an appropriate state by adopting the supply amount control method of the present invention. It could be confirmed.

INDUSTRIAL APPLICABILITY The metering supply device of the present invention is suitable as a device for supplying concentrate to a concentrate burner of a flash furnace in a dry process such as copper smelting.

Reference Signs List 1 constant supply device 2 transport device 3 supply pipe 4 discharge pipe 10 impact type powder mass flowmeter 11 main body 11h drop flow path 12 detection unit 13 detection member 13a collision surface 13b rear surface 13e outer edge 13h penetration space 14 support frame 15 flow rate calculation Part 16 Weighing Part 17 Calculation Part 20 Control Part H Storage Device F Flash Furnace B Concentrate Burner M Concentrate

Claims (2)

A method for adjusting the amount of concentrate supplied to a concentrate burner of a flash furnace using a conveying device from a storage device in which the concentrate is stored,
An impact-type powder mass flow meter is installed in the flow path that conveys the concentrate from the storage device to the concentrate burner of the flash furnace.
The impact mass flow meter is
a main body having a drop channel for dropping the concentrate, which is connected to the channel;
a detecting member having a penetrating space penetrating between a collision surface on which the concentrate collides and a back surface located on the opposite side of the collision surface, the detection member being disposed in the drop channel of the main body;
a flow rate calculation unit that calculates the mass flow rate of the concentrate based on the amount of movement of the detection member,
Maintaining the amount of concentrate conveyed until the mass flow rate detected by the impact-type powder mass flow meter deviates from the reference value for a certain period of time,
When the mass flow rate detected by the impact powder mass flow meter has increased from the reference value for a certain period of time, the amount of concentrate transported by the transport device is reduced,
A supply amount control method, characterized in that when the rate of increase in the mass flow rate detected by the impact type powder mass flow meter exceeds a predetermined rate of increase, the transport of the concentrate by the transport device is stopped. 2. A method according to claim 1 , wherein said impact type powder mass flow meter is arranged immediately before a concentrate burner of a flash furnace.

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