JP7069696B2 - Limestone raw material supply chute - Google Patents

Description

The present invention relates to a chute for supplying a limestone raw material used for preparing a limestone slurry, and a method for preventing the accumulation of the limestone raw material on the chute.

In a nickel smelting plant using the high pressure acid leaching (hereinafter referred to as HPAL) method, valuable metals such as nickel and cobalt are leached by adding sulfuric acid to slurried low-grade nickel ore under high pressure. Processing is being performed. Since the leachate obtained by this leachate contains impurities such as iron, the pH of the leachate is adjusted in the first neutralization step, and then the impurities are removed by solid-liquid separation. After removing impurities, nickel and cobalt as valuable metals are recovered as sulfides by blowing _H2S gas into the leachate. The residual liquid after recovery of the valuable metal is sent to the tailing dam after the pH is adjusted in the second neutralization step.

In the HPAL smelting plant described above, limestone is used to adjust the pH of the process liquid in each neutralization step. This limestone is added to the process liquid in the form of a limestone slurry composed of finely crushed limestone raw material and water from the viewpoint of reaction efficiency and ease of transportation. To prepare this limestone slurry, a conveyor that transports the limestone raw material from the storage location, a chute that receives the limestone raw material that has fallen from the tip of the conveyor and guides it to a predetermined position, and a limestone raw material that is charged from the chute are used. A crusher for crushing, a storage tank for storing the crushed limestone raw material in the form of a limestone slurry together with water added so as to have a predetermined slurry concentration, and a storage tank for storing the limestone slurry extracted from the storage tank are transferred. Therefore, equipment mainly composed of a liquid feed pump that boosts the pressure is generally used.

The chute that guides the limestone raw material toward the crusher is to guide the limestone raw material while sliding it down along the inclined bottom surface. The fine limestone raw material adhered to the bottom surface to form a lump, and the limestone raw material was deposited from there as a starting point, which sometimes caused clogging in the chute. When the deposited lump of limestone raw material becomes large to some extent and the force in the sliding direction exceeds the frictional resistance with the bottom surface of the chute, it falls into the crusher as a large lump, and as a result, the crusher is instantly overloaded. The motor tripped and the equipment stopped frequently.

Various techniques have been proposed to prevent clogging of the limestone raw material in the chute as described above. For example, Patent Document 1 proposes a technique for flowing dry air from the inside to the outside of a chute having a closed structure. It is stated that this method can prevent moist external air from flowing into the chute and can dry the moist limestone inside the chute, thus preventing the limestone from adhering to the inside of the chute. Has been done.

Further, in Patent Document 2, in a fixed chute for charging a powder raw material into a rotary kiln, a steel plate liner independent of the chute is inserted on the powder raw material receiving side, and a commercially available vibrator is attached to the liner. A technique has been proposed in which powder is prevented from adhering to the inside of a chute by continuously vibrating the liner and connecting a general lifting device to the liner to raise and lower the powder.

Japanese Unexamined Patent Publication No. 2008-290045 Japanese Unexamined Patent Publication No. 10-31682

However, in order to dry the limestone raw material inside the chute using the technique of Patent Document 1, equipment for supplying a large amount of dry air is required, which is not practical from the viewpoint of cost. In addition, the technique of Patent Document 2 requires a liner vibration device and an elevating device to prevent powder adhesion, so that the equipment as a whole becomes large, and when it is introduced into the existing limestone slurry preparation equipment, it is a large-scale remodeling work. In this case as well, it was not practical in terms of cost.

On the other hand, in order to suppress the accumulation of limestone raw materials in the chute, it is conceivable to increase the tilt angle of the chute, but in order to change the tilt angle of the chute, it is necessary to change the position of the existing crusher and belt conveyor. The cost of the remodeling work can be enormous. Furthermore, if the tilt angle of the chute changes, the amount of limestone raw material supplied to the crusher may change, and there is a risk of causing frequent equipment outages.

The present invention has been proposed in view of the above circumstances, and even when a limestone raw material having a high water content is handled in a limestone slurry preparation facility, the limestone raw material is less likely to be clogged in the chute, so that the limestone raw material is supplied. The purpose of the above-mentioned crusher is to provide a chute that is less likely to stop due to overload and can improve the operating rate of the equipment.

As a result of intensive research to solve the above-mentioned problem of clogging of the limestone raw material in the chute, the present inventor has installed a plurality of discharge parts for discharging compressed air at both ends in the width direction of the bottom surface of the chute. , It was found that the accumulated limestone raw material can be instantly blown off and the quantitative supply to the crusher can be maintained, and the present invention has been completed.

That is, the chute according to the present invention is a chute having an inclined bottom surface for supplying a limestone raw material and side surfaces located at both ends in the width direction thereof, and slides down along the bottom surface at both ends in the width direction of the bottom surface. A plurality of air discharging portions for discharging compressed air toward the downstream side in the sliding direction of the limestone raw material are arranged , and the direction toward the downstream side in the sliding direction is parallel to the bottom surface and the sliding direction. It is characterized in that it is tilted by 25 to 45 ° with respect to the relative .

Further, the method for preventing the accumulation of a limestone raw material according to the present invention is a limestone that slides along the bottom surface from both ends of a chute having an inclined bottom surface for supplying the limestone raw material and side surfaces located at both ends in the width direction thereof. A method for preventing deposition in which compressed air is discharged in a direction toward the downstream side of the raw material in the sliding direction, and the direction toward the downstream side in the sliding direction is parallel to the bottom surface and 25 with respect to the sliding direction. It is characterized by being tilted by ~ 45 ° .

According to the present invention, even when handling a limestone raw material having a high water content, it is possible to prevent the limestone raw material from being clogged in the chute.

It is a schematic side view of the limestone slurry preparation equipment to which the chute of this invention is preferably applied. It is a perspective view of the chute of embodiment of this invention. It is sectional drawing which saw the chute of FIG. 2 from the direction perpendicular to the bottom surface. It is a side view of the chute of FIG.

Hereinafter, embodiments of the shoot of the present invention will be described in detail with reference to the drawings. The chute of the embodiment of the present invention is used to supply a limestone raw material to a crusher constituting a limestone slurry preparation facility of a nickel HPAL smelting plant. That is, as shown in FIG. 1, the limestone raw material R carried from the stockyard by the belt conveyor 1 is received from the upper end opening of the chute 2 provided below when it falls from the tip end portion thereof. The limestone raw material R received from the upper end opening is guided along the inclined bottom surface of the chute 2, then discharged from the lower end opening of the chute 2 and charged into the crusher 3 located below the lower end opening. ..

As described above, the chute 2 of the embodiment of the present invention, which plays a role of guiding the limestone raw material, has an inclined bottom surface 10 having an elongated substantially inverted trapezoidal shape and the width direction of the bottom surface 10, as shown in FIG. 2, for example. A pair of substantially rectangular side surfaces 11 and 12 located at both ends, and an elongated substantially inverted trapezoidal shape spanning the upper edges of the pair of side surfaces 11 and 12 so as to face the bottom surface 10. It is composed of a lid portion 13, and the upper end opening and the lower end opening serve as an input port and a discharge port for limestone raw materials, respectively.

The chute 2 of the embodiment of the present invention has a plurality of air discharging portions that discharge compressed air toward both ends of the bottom surface 10 in the width direction toward the downstream side of the sliding direction A of the limestone raw material that slides down along the bottom surface 10. 14 are arranged. By blowing compressed air from the plurality of air discharging portions 14 in this way, it is possible to blow off the limestone raw material that tends to be particularly deposited in the corners of the bottom surface 10 and the side surfaces 11 and 12, and thus the quantitative supply of the limestone raw material can be achieved. It will be possible to continue.

As described above, the reason why the plurality of air discharging portions 14 are arranged at both ends in the width direction of the chute 2 is that the limestone raw material adheres not only to the bottom surface of the chute 2 but also to the side surfaces 11 and 12 of the chute 2. This is because a larger amount of limestone raw material is deposited at the corners where 10 and the side surfaces 11 and 12 are orthogonal to each other. The installation position of the plurality of air discharging portions 14 is not particularly limited as long as compressed air is blown from both ends of the bottom surface 10 of the chute 2 in the width direction toward a portion where limestone raw material is likely to be deposited. As shown in FIG. 3, it is preferable to arrange the same number of air discharging portions 14 (three in each in FIG. 3) at both ends of the bottom surface 10 in the width direction at equal intervals in the sliding direction A. In FIG. 3, the center lines of the bottom surface 10 parallel to the sliding direction A are arranged symmetrically with respect to the center line, but instead of this, they may be arranged in a staggered pattern so as to be staggered on the left and right sides.

As the direction in which each of the above air discharging portions 14 faces the downstream side of the sliding direction A, specifically, as shown in FIG. 3, it is preferable to incline 25 to 45 ° with respect to the sliding direction A. If this inclination angle θ exceeds 45 °, compressed air will be blown at an angle closer to the right angle to the sliding direction A of the limestone raw material, so that clogging by the limestone raw material may not be effectively prevented. There is. On the contrary, when the inclination angle is less than 25 °, the corners located on both sides of the bottom surface 10 in the width direction can be effectively prevented from being clogged, but the shoot 2 is deposited in the center portion in the width direction. It becomes difficult to blow off the limestone raw material, and there is a risk of clogging starting from this point.

In the specific examples shown in FIGS. It may be less. However, it is preferable to arrange 6 or more air discharging portions 14 per 2.6 m ² of the bottom surface 10 of the chute 2. This makes it possible to more reliably prevent clogging of the limestone raw material. The upper limit of the number of air discharging portions 14 is preferably as small as possible from the viewpoint of cost and ensuring a wide area of the bottom surface 10.

As a specific structure of each air discharge unit 14, as shown in FIGS. 2 to 4, a nominal diameter of about 1/4 to 1 inch is arranged so that the tip opening portion faces the downstream side of the sliding direction A. However, the method is not limited to the above, and for example, two pipes are provided along both ends in the width direction of the bottom surface 10, and the pipes are spaced apart from each other in the sliding direction. An opening that opens in a direction facing the downstream side of A may be drilled, or a commercially available air nozzle may be used so that compressed air is blown to the downstream side of the sliding direction A at regular intervals in these pipes. It may be attached.

An opening / closing means such as a solenoid valve is provided on the upstream side of each of the plurality of air discharging portions 14, and the compressed air is intermittently blown into the chute 2 by opening / closing these at regular intervals, for example. It is preferable to control it. The timing of intermittent blowing of compressed air is not particularly limited. For example, compressed air may be discharged from all the air discharging units 14 at the same time, or one or several pieces may be discharged in a predetermined order. You may do so. In the above-mentioned intermittent blow control, it is preferable that the frequency of blows per unit time and the release time at each blow can be easily changed. Further, it is preferable that a flow rate adjusting valve such as a globe valve is provided on the upstream side of each air discharge unit 14. As a result, even if the properties such as the water content and particle size of the limestone raw material fluctuate, the supply amount and release time of the compressed air at the time of blowing can be appropriately changed, so that the local deposition of the limestone raw material is more efficient. It can be prevented well.

The pressure of the compressed air supplied to each air discharge unit 14 is preferably 0.7 MPa or more based on the gauge pressure. If the pressure of the compressed air is less than 0.7 MPa, the wind force of the air discharged from the air discharging unit 14 becomes too weak, and it becomes difficult to effectively prevent the clogging of the limestone raw material. As described above, the discharge time of compressed air intermittently discharged from each air discharge unit 14 is preferably 1 second or more and 3 seconds or less. If this release time is less than 1 second, the effect of releasing compressed air can hardly be obtained. On the contrary, if the release time exceeds 3 seconds, it becomes difficult to obtain the effect of intermittent release. Next, specific examples of the shoot of the present invention will be described, but the present invention is not limited to the following examples.

Using equipment including a belt conveyor 1, a chute 2, and a crusher 3 as shown in FIG. 1, a limestone raw material having a particle size of 100 mm or less was crushed while being supplied to the belt conveyor 1 at 80 to 140 t / Hr. The chute 2 has a bottom surface 10 having an area of 2.6 m ² , and as shown in FIG. 3, air discharge portions 14 composed of a total of 6 pipes having a nominal diameter of 3/4 inch are attached to both ends in the width direction thereof. The tip opening was adjusted so as to face a direction inclined by 45 ° with respect to the sliding direction A.

Further, a compressed air supply pipe having a gauge pressure of 0.7 MPa is connected to each air discharge unit 14 via a solenoid valve, and the solenoid valves of the three air discharge units 14 on the left side of the paper in FIG. 3 are continued for 2 seconds from the top. By repeating the air discharge pattern with a 12-second cycle, which consists of opening the solenoid valves of the three air discharge units 14 on the right side of the same page continuously for 2 seconds each from the top, the inside of the chute 2 is opened. Compressed air is always blown from one of the air discharge units 14. In this way, the limestone raw material was pulverized.

For comparison, the limestone raw material was crushed in the same manner as above except that compressed air was not supplied to the chute. Table 1 below shows the results when these compressed airs are blown into the chute and when they are not blown into the chute.

As can be seen from the results in Table 1 above, when compared in a month with a monthly rainfall of about 500 mm / month, the clogging that occurred 15 times when compressed air was not blown into the chute became 2 by blowing compressed air. Decreased to times. That is, in a chute for a limestone raw material applied to a limestone slurry preparation facility, the water content of the limestone raw material is determined by intermittently blowing out compressed air by providing air discharge portions at a plurality of locations at both ends in the width direction of the bottom surface. Even if the properties change, the quantitative supply to the crusher can be almost maintained, and therefore, the equipment stoppage due to the overload of the crusher can be suppressed in a smaller size and cheaper than the conventional powder adhesion prevention device.

1 Belt conveyor 2 Chute 3 Crusher 10 Bottom surface 11, 12 Side surface 13 Cover part 14 Air discharge part A Sliding direction R Limestone raw material

Claims (4)

A chute having an inclined bottom surface for supplying a limestone raw material and side surfaces located at both ends in the width direction thereof, and is a downstream side in the sliding direction of the limestone raw material that slides down along the bottom surface at both ends in the width direction of the bottom surface. A plurality of air discharging portions for discharging compressed air are arranged , and the direction toward the downstream side in the sliding direction is parallel to the bottom surface and tilted by 25 to 45 ° with respect to the sliding direction. A shoot characterized by being. The chute according to claim 1 , wherein 6 or more air discharging portions are arranged per 2.6 m ² of the bottom surface. The pressure of the compressed air supplied to the plurality of air discharge portions is 0.7 MPa or more, and the discharge time of the compressed air from each air discharge port is 1 second or more and 3 seconds or less each time. The shoot according to claim 1 or 2 . Compressed air from the ends of a chute having an inclined bottom surface for supplying the limestone raw material and sides located at both ends in the width direction toward the downstream side in the sliding direction of the limestone raw material sliding along the bottom surface. A method for preventing the accumulation of limestone raw material on a chute, in which the direction toward the downstream side in the sliding direction is parallel to the bottom surface and tilted by 25 to 45 ° with respect to the sliding direction. A method for preventing the accumulation of limestone raw material on a chute.

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