JP6233810B2 - A method for detecting clogging of a mine chute and a mine chute having a clogging detection function - Google Patents

Description

  The present invention relates to a method for detecting clogging of a mine chute and a mine chute having a clogging detection function.

  In a ferronickel smelting plant, for example, a rotary kiln described in Patent Document 1 is used. The raw ore calcined in such a rotary kiln (hereinafter referred to as “calcined ore”) is weighed by a weighing hopper (hereinafter referred to as “surge hopper”) equipped with a load cell, and then charged into a container to the electric furnace of the next process. Conveying. Between these rotary kilns and surge hoppers, a sieving means (hereinafter referred to as rooster) having a predetermined opening is generally provided. This roastle is supplied with the burned ore processed in the rotary kiln, where sieving is performed, and for example, the burned ore having a particle size of less than about 100 mm passes through the rooster and is charged into a surge hopper located almost directly below.

  On the other hand, the large-diameter sinter that cannot pass through the rooster and remains on the sieve surface is extruded from one end on the rooster with a removal device called a pusher that reciprocates in the plane direction on the sieve surface, It is dropped toward a firing chutes (hereinafter also referred to as ring chutes) that are provided obliquely below one end of the rooster and that are different from the surge hopper. The large-diameter sinter ring dropped on the ring chute is sent to the crushing process.

  The pusher is composed of a tip portion made of a rectangular plate member for extruding the ore on the rooster, and driving means for reciprocating the tip portion on the sieve surface. Although the sinter is extruded, some of the sinter remains on the rooster without being extruded. The remaining part of the slag is scraped to the other end opposite to the end where the slag is pushed out during the double action of the pusher. (Hereinafter referred to as back leakage chute) is dropped as back leakage ore.

JP 2014-162937 A

  Of the slag discharged from the rotary kiln, most of the slag that cannot pass through the rooster and remains on the slag is softened by overheating inside the rotary kiln, and the slag attached to the furnace wall is stripped and discharged. It is a sinter with a large particle size and also called a ring. If a large amount of this ring is discharged from the rotary kiln, it is not possible to push the ring on the rooster completely toward the ring chute only by one forward movement of the pusher. It could fall and clog the vicinity of the back leak chute entrance.

  As described above, if the ring or the back leakage mine continues to be dropped on the back leakage chute when the vicinity of the back leakage chute entrance is clogged, the back leakage ore may overflow from the upper inlet of the back leakage chute. As a result, drive means such as a chain and a sprocket that reciprocates the above-described pusher installed near the inlet of the back leakage chute may bite the back leakage ore and cause the pusher to stop abnormally. . When the pusher stops abnormally, it is necessary for the operator himself to manually drop the ring on the rooster to the ring chute in a hot working environment. In some cases, it is also necessary to stop the operation of the rotary kiln. In order to avoid troubles such as an abnormal stop of the pusher during operation, a method for preventing overflow of the back leakage chute has been demanded.

  In order to prevent overflow near the inlet of the back leakage chute, change the shape such as operating the rotary kiln so that no ring is generated or widening the inlet of the back leakage chute so that the ring is not clogged. Think about what to do. However, ring formation may be difficult to avoid depending on operating conditions. On the other hand, changing the shape of the back leak chute is not realistic because it requires a large space for remodeling because it is necessary to secure an empty space around the back leak chute. Therefore, there has been a demand for a method for detecting the clogging of the back leakage chute at an early stage so that the operator can eliminate the clogging at the initial stage before the back leakage chute overflows.

  In order to detect the clogging of the back leakage chute at an early stage, there is a method of detecting clogging in the chute by installing a contact type sensor such as a rotary level sensor or a non-contact type sensor of the opposite type. However, since the temperature of the ore being put into the back leakage chute is very high at 700 to 900 ° C., it is heat resistant to install the contact type clogging sensor and the counter type clogging sensor on the back leakage chute. In addition, the sensor mounting atmosphere is extremely high, and there is a concern that maintenance and maintainability are poor.

  Further, by installing a sensor in the chute, the sensor may cause clogging of the chute. Therefore, there has been a demand for a method for detecting clogging of the back leakage chute at an early stage without installing a sensor in the back leakage chute. The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to detect a clogging of a burning shoot at an early stage and prevent the overflow of the burning shoot.

  In order to achieve the above object, a method for detecting clogging of a sinter ore chute according to the present invention is a method of detecting a slag of 700 to 900 ° C. discharged from a rotary kiln in a ferronickel smelting process and guiding it downward. A method for detecting clogging of the slag, without placing a refractory inside the slag chute, contacting a thermometer to its outer surface and continuously measuring the temperature of the slag chute, When the measured temperature exceeds a predetermined threshold value, it is judged that clogging has occurred.

  Further, the mine chute system according to the present invention includes a mine chute that receives a 700-900 ° C. smelt discharged from a rotary kiln in a ferronickel smelting process and guides it downward, and has a refractory inside the slag chute. It consists of a control device that continuously measures the temperature with a thermometer that is in contact with the outer surface of the part where no object is applied, and transmits a clogging signal when the measured temperature exceeds a predetermined threshold value. It is characterized by.

  According to the present invention, it is possible to detect clogging of a sinter at an early stage, and thus it is possible to respond quickly before the slag overflows.

It is a block flow figure showing the general flow of the raw material ore processed with the rotary kiln of a ferronickel smelting process. It is a longitudinal cross-sectional view which shows typically the installation of the back | latter stage of the rotary kiln to which the detection method of the clogging of the calcination chute which concerns on this invention is applied. It is a graph which shows the temperature profile when the burning mine chute referred in the detection method of the clogging of the firing mine according to the present invention is clogged. It is a graph which shows a temperature profile when a back leak chute is clogged in an Example.

  Hereinafter, a specific example of the method for detecting clogging of a sinter according to the present invention will be described with reference to the drawings. FIG. 1 is a block flow diagram showing the treatment of the sinter after the treatment with the rotary kiln generally performed in a ferronickel smelting plant. FIG. 2 schematically shows an apparatus for performing each process shown in FIG. As shown in FIG. 2, the burned ore processed in the rotary kiln 1 is discharged from the end of the rotary kiln 1 and supplied onto a rooster 2 provided below the mines. The rooster 2 has a sieve portion having a predetermined opening. Here, the relatively small sized ore that passes through the rooster 2 and the relatively sized residue that remains on the rooster 2 without passing through the rooster 2. Sifted into large sinter.

  The burned ore that has passed through the rooster 2 is charged into a surge hopper 3 provided almost directly below the rooster 2. On the other hand, the burned ore remaining on the rooster 2 is pushed out by the pusher 4 and falls to the ring chute 5 provided obliquely below one end of the rooster 2, and is scraped off when the pusher 4 returns to the rooster 2. It is divided into two types of sinters with the back leakage ore falling on the back leakage chute 6 provided obliquely below the other end of the bottom.

  In the configuration on the downstream side of the rotary kiln 1 as described above, if the sinter is overheated due to fluctuations in the processing conditions in the rotary kiln 1 as described above, a large amount of rings that cannot pass through the rooster 2 become the back leakage chute 6. It could fall and clog, and overflow from its inlet. As a result of studying a method that can detect the clogging in the initial stage before the overflow, the inventor has found that the back leak chute 6 is not covered with a refractory inside the back leak chute 6 with a thermometer provided on the outer surface thereof. The inventors have found that the initial stage clogging in the back leakage chute 6 can be detected at an early stage by continuously measuring the temperature, and the present invention has been completed.

  More specifically, the sinter discharged from the rotary kiln in the ferronickel smelting process has a temperature of about 700 to 900 ° C., but this sinter becomes a back leak chute as a back leak ore at normal times. Since the fall amount is small, it passes without staying in the back leakage chute. Therefore, even if no refractory is installed on the inside of the back leakage chute, the temperature of the back leakage chute body becomes the heat resistant temperature of the iron member due to heat radiation from the outer surface of the back leakage chute or heat transfer to the floor surface where it is installed. It is possible to maintain a temperature of about 400 ° C. or less, which is a measure of the above. However, once clogging occurs in the back leakage chute, the amount of heat transferred from the ore to the wall surface exceeds the amount of heat released from the outer surface, and the temperature of the wall surface rises rapidly. Therefore, by installing a thermometer on the outer surface as close as possible to the place where clogging is likely to occur in the back leakage chute where no refractory material is installed inside this, it is possible to detect this internal clogging at an early stage. Is possible.

  Since the temperature of the sinter is 700 to 900 ° C, a sheath thermocouple is preferable as the type of thermometer, and in particular, it can be measured up to about 1000 ° C in order to enable accurate temperature measurement corresponding to the sinter temperature. A thermometer is preferred. The thermometer mounting method is, for example, preparing a rectangular parallelepiped metal plate of the same material as the sheath material of the sheath thermocouple, for example, and inserting the temperature detection part at the tip of the sheath thermocouple into the hole provided on the side surface, The surface of the metal plate is fixed in contact with the outer surface of the back leakage chute. By attaching in this way, it becomes possible to measure the temperature of the wall surface with high accuracy without adversely affecting the flow of the ore falling in the back leakage chute. As a method of fixing the rectangular parallelepiped metal plate to the outer surface of the back leakage chute, a general method such as welding or screwing can be used.

  Referring to FIG. 2 again, the back leakage chute 6 is composed of a funnel-shaped receiving portion 6a and a pipe-shaped guide portion 6b provided at the lower discharge port of the receiving portion 6a. The thermometer 7 is attached to the connection part of the receiving part 6a and the guide part 6b among the outer surfaces of 6. FIG. The measurement value obtained by the thermometer 7 is input to the control device 8, where it is determined whether or not the measurement value exceeds a temperature threshold that is assumed to be clogged. When the measured value exceeds the temperature threshold value, a clogging signal is transmitted. This clogging signal is displayed, for example, on a monitor 9 provided in the cab. Note that the monitor 9 may always display the temperature measured by the thermometer 7. The temperature threshold for determining the occurrence of clogging described above may be determined based on temperature rise data obtained when the ring is intentionally dropped and clogged on the back leakage chute 6 in a state where there is no clogging.

For example, as shown in FIG. 3, when deliberately dropped the ring back leakage chute 6 at time t _0, the temperature profile measured temperature at time t ₀ increases rapidly. In this case, by setting T _th higher than any temperature before time t ₀ as the temperature threshold, it is possible to generate a clogging signal at time t _{1 at} a very early stage when the back leakage chute 6 overflows. Become.

  As shown in FIG. 3, in order to cause the measured temperature to rapidly increase when clogging occurs in the back leakage chute 6, the thermometer 7 is received in a funnel shape in which sinter is charged in the back leakage chute 6. It is preferable to attach to the outer surface of the part 6a or the outer surface within the range from the upper end to 1 m in the pipe-shaped guide part 6b provided in the lower discharge port of the receiving part 6a. This is because the joint portion between the receiving portion 6a and the guide portion 6b is a portion narrowed in the back leakage chute 6, and the clogging of the sinter occurs most in this narrowed portion.

If it is difficult to install the thermometer in the above range due to physical reasons or workability during maintenance, for example, it will be away from the position where the ore is clogged. In this case, the sensitivity for detecting the temperature rise is reduced. In this case, a temperature lower than the temperature threshold T _th and higher than any temperature before the time t ₀ in FIG. 3 may be set as the temperature threshold. In this case, clogging occurs even when there is no clogging. A signal may be emitted.

Example 1
The sinter burned in the rotary kiln 1 having an outer diameter of 4.8 m is supplied onto the rooster 2 equipped with the pusher 4 as shown in FIG. A test was carried out in which the back leakage chute 6 was clogged with sinter by dropping to the 6th side. The thermometer 7 uses a sheathed thermocouple, and the temperature detecting part at the tip of the sheathed thermocouple is fitted into a hole provided in a side surface of a rectangular parallelepiped metal plate made of the same material as the sheath material. And the surface of this rectangular parallelepiped metal plate was made to contact | abut to the outer surface of the junction part of the funnel-shaped receiving part 6a and the pipe-shaped guide part 6b, as shown in FIG. The measured value of this thermometer was input to the control device 8. Since the temperature of the sinter was as high as 700 to 900 ° C., the temperature threshold for judging the occurrence of clogging in the control device 8 was set to 400 ° C.

  In this state, the ring of the rotary kiln 1 was changed to intentionally produce a ring, and the temperature of the thermometer was continuously monitored while dropping the ring onto the back leakage chute 6 side. The measurement result of continuously measuring the temperature of the back leakage chute 6 is shown in FIG. In FIG. 4, it can be seen from the temperature data at 5:00 that the temperature of the back-leakage chute is normally about 100 to 150 ° C. However, the temperature suddenly increased at 5:56, and at 5:58, the temperature rose to 400 ° C. or higher, which is the temperature for detecting clogging. At that time, an alarm was issued and clogging was eliminated, and the temperature decreased to about 100 ° C. Therefore, it was confirmed that the back leakage chute, that is, the clogging of the ore chute can be detected by the method of the present invention.

(Example 2)
The thermometer mounting position is 2 m downstream from the joint between the lower end of the funnel-shaped portion of the back leak chute and the pipe-shaped portion of the back leak chute provided at the lower end of the funnel-shaped portion. A test was conducted in which the back leakage chute 6 was clogged with sinter in the same manner as in Example 1 except that the temperature threshold was set to 200 ° C. As a result, the value of the thermometer was changed at about 100 to 150 ° C., and when the clogging occurred, the temperature rise could be confirmed well and clogging of the back leakage chute could be detected early. However, since the threshold was 200 ° C., erroneous detection occurred about once or twice a week.

1 Rotary kiln 2 Rooster 3 Weighing hopper (surge hopper)
4 Pusher 4a, 4b Reciprocation limit of pusher 5 Ring chute 6 Back leak chute 7 Thermometer 8 Controller 9 Monitor

Claims (5)

  It is a method for detecting clogging of a smelting chute that accepts 700-900 ° C sinter discharged from a rotary kiln in a ferronickel smelting process and guides it downward, and a refractory is installed inside the sinter chute. The temperature of the ore chute is continuously measured by bringing a thermometer into contact with the outer surface of the ore, and the cinder is judged to be clogged when the measured temperature exceeds a predetermined threshold value. Chute clogging detection method.   The method of claim 1, wherein the thermometer is a sheathed thermocouple capable of measuring up to 1000 ° C.   The thermometer is attached by inserting a temperature detection part at the tip of the sheath thermocouple into a hole provided in a metal member of the same material as the sheath material of the sheath thermocouple, and the surface of the metal plate is placed on the surface of the mining chute. The method for detecting clogging of a baked ore chute according to claim 2, wherein the clogging is caused to abut on an outer surface.   The thermometer is placed on the outer surface of the funnel-shaped receiving portion of the mine chute or on the outer surface within a range of 1 m from the upper end of the pipe-shaped guide portion provided at the lower discharge port of the receiving portion. The method for detecting clogging of a baked ore chute according to any one of claims 1 to 3, wherein the method is attached.   The smelting chute that receives 700-900 ° C sinter discharged from the rotary kiln of the ferronickel smelting process and guides it downward, and the outer surface of the smelting chute where no refractory is applied inside A firing chute system comprising: a controller that continuously measures a temperature with a thermometer in contact with the controller and that transmits a clogging signal when the measured temperature exceeds a predetermined threshold value.

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