JP7124913B2 - Ore sorting method and its device - Google Patents

Description

The present invention relates to an ore sorting method for sorting non-defective ore from pulverized rock, and more particularly to an ore sorting method and apparatus for sorting non-defective ore from pulverized rock in the process of dropping the pulverized rock.

As a conventional ore sorting method, taking gold ore as an example of an object to be sorted, the gold ore is crushed and then pulverized to an appropriate particle size, and the obtained ore grains are suspended in an aqueous cyanide solution. A method of separating and concentrating gold from gangue minerals and sulfide minerals by the so-called cyanide method of leaching gold, and a method of separating and concentrating gold minerals from gangue minerals and sulfide minerals by gravity concentration and flotation, and then further cyanide. A method of separating and concentrating gold according to the law is adopted.
However, in order to carry out these methods, the ore must be pulverized to several tens of microns to several hundreds of microns, which requires a very large amount of energy. In other words, the as-mined ore contains many masses of host rocks containing little gold and silver, and crushing such host rocks into such fine particles wastes energy. will do. In addition, since host rocks contain a large amount of clay minerals, it is generally well known that clay minerals have an adverse effect on the cyanide method, the solvent in copper refining, and the flotation method. is.

Originally, quartz containing gold and silver is white, and can be easily distinguished visually from the gray or black host rock. Therefore, as a method of removing host rock from coarsely crushed materials, automatic sorting by an ore sorting device is known that performs an optical inspection and distinguishes whether or not it is host rock.
In the ore sorting apparatus as described above, for example, as described in Patent Document 1, an article is conveyed at a high speed by a belt conveyor at a constant speed, and the article is protruded from the pulley end of the belt conveyor to the side, and the pulley end protrudes. It is possible to apply a technique of inspecting the image in the horizontal flight state immediately after, and selecting the quality of the article by using the air nozzle row controlled by the electromagnetic valve and changing the trajectory of the falling flight.

In addition, although the sorting object is not ore, grain sorting apparatuses are already known, for example, those described in Patent Documents 2 to 4.
In Patent Document 2, grains mixed with different grains supplied from a vibrating feeder through a trough are allowed to pass through a gap of a photoelectric device formed by a light source and a light receiving element in a substantially constant trajectory. A light-receiving element receives a light beam emitted from a light source to mixed grains and passes through the grains, and the light-receiving element is provided at a position where the grains that have passed through the gap can be blown off according to the signal of the light-receiving element depending on the degree of light intensity. A grain color sorting device is disclosed in which a light receiving element and an electromagnet control device for opening and closing an open/close valve of a blowpipe are connected.

Further, in Patent Document 3, while a vibration supply gutter is provided on the transport start side of a material transport belt that is rotatably horizontally installed by a pair of rollers, the vibrating supply gutter is provided near the trajectory of the material falling from the transport end of the transport belt. and an ejector actuated by a signal from a control unit communicating with the detecting unit is provided on the trajectory, wherein the conveying surface of the conveying belt is positioned on the conveying end side. A granular matter color sorter is disclosed which is inclined so that the transport start end side is higher than the granules.
Furthermore, in Patent Document 4, a rotary valve is provided directly below the raw material supply hopper and the reselection hopper, and a belt conveyor is arranged on a horizontal surface below the rotary valve, and the grain is placed on the rotary valve A grain sorter is disclosed in which the grain is discharged onto a belt conveyor from the end and free-falls from the terminal end to be fed to an inspection and sorting position.

Japanese Patent Application Laid-Open No. 2008-55274 (best mode for carrying out the invention, FIG. 1) Japanese Patent Application Laid-Open No. 55-56874 (detailed description of the invention, FIG. 2) Japanese Patent Application Laid-Open No. 8-108146 (Example, FIG. 1) Japanese Patent Application Laid-Open No. 9-122606 (Embodiment of the Invention, FIG. 3)

However, for example, in Patent Document 1, since it is a method of sorting the quality of ore, which is an article, by horizontal flight by high-speed transportation, it is not only necessary to secure a wide installation space for the device in the horizontal direction. , it is necessary to control the transportation so that the ore flies horizontally with respect to the horizontal distance between the image inspection camera and the air nozzle row.
Furthermore, in Patent Document 1, when the ore is fed and conveyed on a belt conveyor in a dense state in order to increase the throughput, the ore may overlap up and down, and if it overlaps up and down, it will be hidden underneath. The ore that has been removed will not appear in the image, and the ore sorting performance will decrease. Also, if the ores do not overlap but are adjacent to each other, the probability of shooting down the ores that should not be shot by the air nozzle increases, lowering the ore processing performance. Therefore, it is necessary to transport the ores in a scattered state so that the ores are not adjacent to each other and do not overlap each other, and there is a concern that it is difficult to increase the processing amount.

In Patent Documents 2 and 3, grains are sorted based on grain permeation information, and different grains are blown away. The falling speed, the falling trajectory, and the rotation speed at the time of falling are stable even if the ore is slid and dropped, whereas the crushed rock containing the ore, which is the object of selection in this application, is not uniform in size and has a shape Therefore, if a similar method is adopted, the way the flow gutter slides will not be stable due to the difference in slip resistance, or it will slide down as if it is rolling, resulting in the falling speed, the falling trajectory, and the rotational speed at the time of falling. is likely to become unstable, and there is concern that the ore sorting performance will decline.
Moreover, in Patent Document 4, grains can be sent to the inspection position regularly, uniformly and stably, and the supply amount of the grains to be sent to the inspection position can be changed. As a result, the inspection and sorting of whether or not the grains are defective can be performed with high accuracy and efficiency. However, crushed rocks containing ore, which is the object of sorting in the present application, are not uniform in size and have various shapes, so it is difficult to adopt the same method as it is.

The technical problem to be solved by the present invention is to image the ore along a stable falling trajectory of crushed rock from the downstream end of the conveying direction of the belt-shaped conveying body without the need for complicated conveying control with a compact equipment configuration.・It is to supply the ore to the sorting stage so that the ore can be sorted.

In the invention according to claim 1, when sorting non-defective or defective ore predetermined by the content ratio of the target mineral from the crushed rock, the rock is stretched over a plurality of tension rolls and circulated, a supply step of using a belt-shaped conveying body for conveying the pulverized material so as to drop the pulverized rock material from the downstream end of the belt-shaped conveying body in the conveying direction along a predetermined parabolic drop trajectory; an imaging step of capturing an image of the pulverized rock supplied in the supply step from a direction intersecting with the direction of gravity in the middle of the falling trajectory; A sorting process in which air is blown toward one of the objects from a direction intersecting the direction of gravity so that the trajectories of the selected non-defective ore and defective ore are different; In the supplying step, at the curved portion that is stretched over the tension roll located at the downstream end of the conveying direction of the belt-shaped conveying body, the crushed rock material is distributed along the curvature of the peripheral surface of the curved portion . The ore sorting method is characterized in that the ore sorting method is characterized in that the ore is conveyed in a state of zero biting without slipping at the contact portion with the curved portion while drawing a falling trajectory.
In the invention according to claim 2, when sorting non-defective or defective ore predetermined by the content ratio of the target mineral from the crushed rock, the rock is stretched over a plurality of tension rolls and circulated, and the rock a supply step of using a belt-shaped conveying body for conveying the pulverized material so as to drop the pulverized rock material from the downstream end of the belt-shaped conveying body in the conveying direction along a predetermined parabolic drop trajectory; an imaging step of capturing an image of the pulverized rock supplied in the supply step from a direction intersecting with the direction of gravity in the middle of the falling trajectory; A sorting process in which air is blown toward one of the objects from a direction intersecting the direction of gravity so that the trajectories of the selected non-defective ore and defective ore are different; In the supplying step, at the curved portion that is stretched over the tension roll located at the downstream end of the belt-shaped carrier in the conveying direction, the crushed rock material has a curvature less than the curvature of the peripheral surface of the curved portion. The ore sorting method is characterized in that the ore sorting method is characterized in that the ore is conveyed in a state in which it draws a drop trajectory along the curvature and does not slip at the contact portion with the curved portion and does not bite into the portion.

The invention according to claim 3 is an ore sorting device for sorting out good or defective ores predetermined by a target mineral content ratio from crushed rocks, wherein the crushed rocks are sorted in a predetermined parabolic shape. an imaging device that captures an image of the pulverized rock supplied by the feeding device from a direction intersecting the direction of gravity on the way of the dropping trajectory; and an imaging result by the imaging device. and a discriminating device that discriminates non-defective ore from the rock pulverized product based on the above, and non-defective or non-defective ore that has fallen below the imaging position of the imaging device based on the discrimination result of the discriminating device. and an air blowing device for blowing air toward one of the objects from a direction intersecting the direction of gravity so that the trajectory of falling of each object is different, and the supply device is stretched over a plurality of tension rolls. A belt-shaped carrier that circulates and moves the crushed rock material, and a curved portion that is stretched over the tension roll positioned at the downstream end of the belt-shaped carrier in the conveying direction. The belt-like conveying body is conveyed in a predetermined manner so that it draws a drop locus along the curvature of the peripheral surface of the curved portion and is conveyed in a state of zero biting without slipping at a contact portion with the curved portion . and a drive device driven at a speed.
The invention according to claim 4 is an ore sorting device for sorting good or defective ores predetermined by a target mineral content ratio from rock pulverized materials, wherein the rock pulverized materials are sorted in a predetermined parabolic shape. an imaging device that captures an image of the pulverized rock supplied by the feeding device from a direction intersecting the direction of gravity on the way of the dropping trajectory; and an imaging result by the imaging device. and a discriminating device that discriminates non-defective ore from the rock pulverized product based on the above, and non-defective or non-defective ore that has fallen below the imaging position of the imaging device based on the discrimination result of the discriminating device. and an air blowing device for blowing air toward one of the objects from a direction intersecting the direction of gravity so that the trajectory of falling of each object is different, and the supply device is stretched over a plurality of tension rolls. A belt-shaped carrier that circulates and moves the crushed rock material, and a curved portion that is stretched over the tension roll positioned at the downstream end of the belt-shaped carrier in the conveying direction. The belt-like conveying body is determined in advance so that the belt-like conveying body draws a drop trajectory along a curvature smaller than the curvature of the peripheral surface of the curved portion, and is conveyed in a state where it does not slip at the contact portion with the curved portion and does not bite. and a driving device that drives the ore sorting apparatus at a set conveying speed with a permissible range of about zero biting.

The invention according to claim 5 is the ore sorting apparatus according to claim 4, wherein the driving device increases the conveying speed of the belt-shaped conveying body by less than 20% with respect to the conveying speed at which the biting amount is 0. An ore sorting apparatus characterized by selecting a conveying speed.
The invention according to claim 6 is the ore sorting apparatus according to claim 3 or 4 , wherein the discriminating device extracts gradation information caused by the ore from the imaging result of the crushed rock, and the ratio of this gradation information is determined in advance. The ore sorting apparatus is characterized in that the ore is determined to be a non-defective product when the ore is equal to or greater than a predetermined threshold value.
The invention according to claim 7 is the ore sorting apparatus according to claim 3 or 4 , wherein the discriminating device determines an air blowing start time and a The ore sorting apparatus is characterized by adjusting the start of the air blowing operation and the air blowing time of the air blowing device by calculating the projected area facing the direction of gravity of the ore, which is the object to be sprayed.

According to the invention of claim 1 or 2 , the ore is imaged along a stable drop trajectory of crushed rocks from the downstream end of the belt-shaped conveying body in the conveying direction, with a compact equipment configuration and without the need for complicated conveying control.・Supplied to the sorting stage, it is possible to sort out good or defective ore.
According to the invention according to claim 3 or 4 , the ore is imaged along a stable drop trajectory of crushed rocks from the downstream end in the conveying direction of the belt-shaped conveying body with a compact equipment configuration and without the need for complicated conveying control.・It is possible to embody an ore sorting method that can supply the ore to the sorting stage and sort out good ore defective items.
In particular, according to the invention of claim 1 or 3 , rocks are placed from the downstream end of the belt-like conveying body in the conveying direction in a state where the amount of bite into the curved portion of the belt-like conveying body stretched over the tension roll is 0. It is possible to supply the pulverized material while suppressing variations in the drop time, the amount of protrusion, and the amount of rotation.
According to the invention according to claim 2 or 4 , the belt-like conveying body is set to the curved portion of the belt-like conveying body stretched over the tension roll, with the permissible range being the vicinity of the biting amount of 0 in the state of no biting amount. It is possible to supply crushed rocks from the downstream end in the conveying direction while suppressing variations in drop time, amount of protrusion, and amount of rotation.
According to the fifth aspect of the invention, it is possible to easily select an allowable range in the vicinity of the biting amount of 0 in a state of no biting amount for the curved portion of the belt-like conveying body that is stretched over the tension rolls. .
According to the sixth aspect of the invention, it is possible to accurately discriminate between non-defective products and defective products in a mode in which the ore to be sorted has gradation characteristics.
According to the seventh aspect of the invention, air can be blown by the air blowing device against the object to be air-blown without waste.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the outline|summary of embodiment of the ore sorting method to which this invention was applied, and its apparatus. 1 is an explanatory diagram showing the overall configuration of an ore sorting device according to Embodiment 1. FIG. FIG. 2 is an explanatory diagram showing a main part of the ore sorting device according to Embodiment 1; FIG. 3 is an explanatory diagram showing a control system of the ore sorting device according to Embodiment 1; 4 is a flow chart showing an ore sorting process according to Embodiment 1. FIG. (a) is an explanatory diagram showing a method for determining whether or not an object is an ore from the result of imaging by a camera, and (b) is an explanatory diagram showing an example of determination from the result of imaging by a camera. (a) is an explanatory diagram showing an example of calculation of the speed v (v ₁ , v ₂ ) of ore passing in front of the camera and nozzle array, and the elapsed time t (t ₁ , t ₂ ) of falling, and (b) is a camera FIG. 7C is an explanatory diagram showing an example of calculation of the size of ore from imaging results, and FIG. (a) is an explanatory diagram showing the behavior of ore accompanying air blowing from a blowing nozzle, and (b) is an explanatory diagram schematically showing the air blowing operation from the blowing nozzle accompanying falling ore. FIG. 10 is an explanatory diagram showing a main part of an ore sorting device according to Embodiment 2; (a) is an explanatory view showing an example of the air blowing operation by the two-row type blowing nozzle used in Embodiment 2, and (b) shows another example of the air blowing operation by the same blowing nozzle. Explanatory drawing, (c) is explanatory drawing which shows typically the air blowing operation|movement by a two-row type blowing nozzle accompanying the fall of an ore. (a) is an explanatory diagram showing an example of air spraying operation by a three-row type spray nozzle used in a modified form, and (b) to (d) are other air spraying operations by the same spray nozzle. FIG. 4 is an explanatory diagram showing an example; (a) is an explanatory view showing the behavior of the ore dropped from the belt conveyor in the ore sorting apparatus according to the first embodiment, and (b) is an explanatory view comparing the behavior of the ore when dropped by the belt conveyor method and the vibration feeder method. is. FIG. 5 is an explanatory diagram showing the relationship between the falling time of ore falling from a belt conveyor and the conveying speed of the belt conveyor in the ore sorting apparatus according to Example 1; FIG. 4 is an explanatory diagram showing the relationship between the amount of ore falling from a belt conveyor and the conveying speed of the belt conveyor in the ore sorting apparatus according to Example 1; 4 is an explanatory diagram showing the relationship between the amount of rotation of ore falling from a belt conveyor and the conveying speed of the belt conveyor in the ore sorting apparatus according to Example 1. FIG. FIG. 4 is an explanatory diagram showing a simulation of the ore drop trajectory from the tip of the conveyor at each conveying speed of the belt conveyor (roll diameter: 200 mm) used in Example 1; FIG. 4 is an explanatory diagram showing a simulation of the ore drop trajectory from the tip of the conveyor at each conveying speed of the belt conveyor (roll diameter: 300 mm) used in Example 1; FIG. 10 is an explanatory diagram showing the distribution of flight distances associated with air blowing in the ore sorting apparatus (drop of 550 mm from the conveying surface of the belt conveyor to the air blowing position) according to Example 2-1; FIG. 10 is an explanatory diagram showing the distribution of flight distances associated with air blowing in the ore sorting apparatus (drop of 750 mm from the conveying surface of the belt conveyor to the air blowing position) according to Example 2-2. FIG. 10 is an explanatory diagram showing the distribution of the amount of rotation of ore in the head of 550 mm in the ore sorting apparatus according to Example 2-1. FIG. 10 is an explanatory diagram showing the distribution of the amount of rotation of ore in the head of 750 mm in the ore sorting apparatus according to Example 2-2; FIG. 11 is an explanatory diagram showing changes in flying distance due to differences in air blowing conditions in the ore sorting apparatus according to Example 3; FIG. 10 is an explanatory diagram showing changes in ore drop angle due to differences in air blowing conditions in the ore sorting apparatus according to Example 3;

◎Outline of Embodiment FIG. 1 shows an outline of an embodiment of an ore sorting method and apparatus to which the present invention is applied.
In the figure, in the ore sorting method, when sorting good ore 1a and defective ore 1b determined in advance by the content ratio of the target mineral from the crushed rock 1, the ore is circulated across a plurality of tension rolls 9a. A moving belt-shaped carrier 6 for carrying the crushed rock 1 is used, and the crushed rock 1 is dropped from the downstream end of the belt-shaped carrier 6 in the conveying direction along a predetermined parabolic drop trajectory w. A supply step A for supplying, an imaging step B for imaging the pulverized rock 1 supplied in the supply step A from a direction intersecting the direction of gravity in the middle of the fall trajectory w, and an imaging step based on the imaging result of the imaging step B. A non-defective ore 1a and a defective ore 1b are sorted from the crushed rock 1 that has passed through B, and the selected non-defective ore 1a and defective ore 1b fall in different trajectories w (w1 and w2 in this example). , and a sorting step C in which air is blown from a direction intersecting the direction of gravity toward one of the objects (the good ore 1a is exemplified in FIG. 1). At the curved portion stretched over the tension roll 9a positioned at the downstream end in the conveying direction, the pulverized rock 1 draws a falling trajectory w with a curvature close to the curvature of the peripheral surface of the curved portion, and at the contact portion with the curved portion It is transported without slipping.

In this example, the method of sorting good ore 1a and defective ore 1b is to set a threshold of the content ratio of the target mineral in the ore in advance, ore above the threshold is regarded as good 1a, and ore less than the threshold is regarded as defective 1b. It is to sort out.
Here, as for the supply step A, a typical mode is that the pulverized rock material 1 is let out and dropped by a belt conveyor system at a predetermined speed, and supplied to the sorting stage.
Further, the imaging process B may be a process of capturing an image of ore in the middle of falling using the imaging device 3, and may be performed not only from one direction but also from a plurality of directions.
Furthermore, in the sorting process C, the good ore 1a and the bad ore 1b to be sorted are sorted out through the imaging process B, and air is blown to one of the objects to change the drop trajectory w, and the good ore is selected. It is sufficient if it physically sorts 1a and defective products 1b. In this case, whether the object to be sprayed is the non-defective product 1a or the defective product 1b may be selected as appropriate. It is preferable to be attached. The reason for this is that the smaller the ratio of the target to be sprayed, the smaller the amount of air to be sprayed, making it possible to reduce the load on the compressor for air compression.

As shown in FIG. 1, an ore sorting apparatus that embodies the ore sorting method sorts out good ore 1a and defective ore 1b predetermined by the content ratio of the target mineral from the pulverized rock 1. A supply device 2 for supplying pulverized rock 1 so as to drop it along a predetermined parabolic drop trajectory w; An imaging device 3 that takes an image from a direction that intersects the direction of gravity; Based on the determination result, one of the objects is set so that the falling trajectories w (w1 and w2 in this example) of the good ore product 1a and the defective ore product 1b that have fallen below the imaging position of the imaging device 3 are different. and an air blowing device 5 for blowing air from a direction crossing the direction of gravity.
In FIG. 1, reference numeral 8 denotes a sorting container for sorting and storing the good ore 1a or the defective ore 1b. It has a structure divided by a partition wall.

In such a technical means, the discriminating device 4 recognizes the non-defective ore 1a or the non-defective ore 1b based on the imaging result of the imaging device 3, so that the non-defective ore 1a Any device that can discriminate the defective product 1b is acceptable. The discrimination method here is based on the characteristics of the minerals in the ore, for example, focusing on the density information for minerals having concentration characteristics, and selecting the mineral ratio from this density information. For minerals having color characteristics, attention should be paid to the color information, and the mineral ratio may be appropriately selected based on the color information.
The air blowing device 5 is intended to blow crushed rock 1 that has fallen below the imaging position, and the blowing direction is a direction intersecting the direction of gravity (not only the horizontal direction, but also the ) is acceptable.

Next, typical aspects or preferred aspects of the ore sorting apparatus according to the present embodiment will be described.
First, as a typical embodiment of the supply device 2, as shown in FIG. At the curved portion stretched over the tension rolls 9a located at the downstream end in the conveying direction of the body 6, the crushed rock 1 draws a falling trajectory w with a curvature close to the curvature of the peripheral surface of the curved portion, and falls with the curved portion . and a driving device 7 for driving the belt-like conveying body 6 at a predetermined conveying speed v so that the contact portion is conveyed without slipping.
In this example, the crushed rock material 1 is let out and dropped by the belt-like conveying body 6 having a predetermined conveying speed v.
Here, when the crushed rock material 1 is conveyed by the belt-like conveying body 6, the conveying speed v of the belt-like conveying body 6 is preferably adjusted within a predetermined range. In this example, the fact that the conveying speed v of the belt-like conveying body 6 is adjusted within a predetermined range means that the belt-like conveying body 6 is stretched over the tension roll 9a positioned at the downstream end in the conveying direction. The condition was that the pulverized rock 1 was conveyed at the curved portion without slipping at the contact portion with a drop trajectory w having a curvature close to the curvature of the peripheral surface of the curved portion.
Now, assuming that the conveying speed v of the belt-like conveying body 6 exceeds a predetermined range, the crushed rock material 1 has a large horizontal velocity component at the downstream end of the conveying direction of the belt-like conveying body 6. fly in the state In this state, the falling trajectory w of the pulverized rock 1 is stable, but the horizontal flight distance of the pulverized rock 1 increases due to the large horizontal velocity component. There is a concern that the horizontal dimension of the mineral sorting device will become large.
On the other hand, when the conveying speed v of the belt-like conveying body 6 falls below the predetermined range, the conveying speed v of the belt-like conveying body 6 decreases at the curved portion of the belt-like conveying body 6 stretched over the tension rolls 9a. Because of the slow speed, the crushed rock 1 slips at the contact portion with the curved portion , and the fall start position of the crushed rock 1 separating from the belt-like conveying body 6 varies, or the crushed rock 1 separates from the belt-like conveying body 6. There is a concern that the drop starting posture of the crushed rock 1 may vary, and the falling trajectory w of the crushed rock 1 may become unstable.
Further, as a representative aspect of the discriminating device 4, gradation information due to the ore is extracted from the imaging result of the crushed rock 1, and when the ratio of the gradation information is equal to or higher than a predetermined threshold value, the ore is a non-defective product. There is an aspect in which it is determined that there is.
Furthermore, as a preferred embodiment of the discriminating device 4, based on the imaging result of the imaging device 3, the air blowing start time for the ore, which is the air blowing target, and the projection of the ore, which is the air blowing target, facing the direction of gravity By calculating the area, there is a mode in which the start of the air blowing operation by the air blowing device 5 and the air blowing time are adjusted. In this example, based on the imaging result of the imaging device 3, the air blowing start time of the target object passing in front of the air blowing device 5 and the projected area facing the direction of gravity are calculated. The air blowing operation by the air blowing device 5 may be started from the blowing start time, and the air blowing operation may be continued facing the projected area of the object to which the air is blown. As a result, the air blowing operation is performed on the air blowing object passing in front of the air blowing device 5, and is rarely performed on useless areas other than the air blowing object.

Furthermore, as a representative aspect of the air blowing device 5, when the size of the crushed rock 1 is within a range of a predetermined minimum size or more and a maximum size or less, the air blowing device 5 can blow air individually. and the nozzles having a diameter smaller than the minimum dimension are horizontally arranged at a pitch smaller than the minimum dimension. When the size of the pulverized rock 1 is determined within a predetermined range by sieving, when selecting the air blowing device 5, if nozzles with diameters smaller than the minimum dimension are arranged horizontally at a pitch less than the minimum dimension, the minimum It is possible to blow air even on the sized rock crushed material 1 .
Furthermore, as a preferred mode of the air blowing device 5, there is a mode in which nozzles capable of individually blowing air are arranged in parallel in the horizontal direction and have a plurality of stages in the direction of gravity. Although this example shows a mode in which the nozzle rows are arranged in a plurality of stages, the nozzles in each row may blow air at the same time or separately. Further, the spraying direction may be parallel, or may be non-parallel so that the spraying is concentrated in one place.
Further, as another preferable aspect of the air blowing device 5, when air is blown to either the non-defective ore 1a or the defective ore 1b, the upward blowing force component of the air against the object to be blown is There is an embodiment in which air is blown so as to generate
In this example, focusing on the behavior of the object to be sprayed with air falling while rotating along the drop trajectory w, the rotational posture of the object to be sprayed with air is changed, for example, so that the upper side of the object to be sprayed with air is downward. If the posture is tilted so as to approach the air blowing device 5 side rather than the side, the blowing force of the air gives an upward blowing force component to the object to be sprayed. In this case, the upward spraying force component acts on the object to be sprayed, and a resistance force is generated when the object to be sprayed falls. It is possible to secure a large flying distance of the object accompanying the blowing of air by 5.
Further, as a further preferred embodiment of the air blowing device 5, when blowing air onto either the non-defective ore 1a or the defective ore 1b, the projection plane facing the direction of gravity of the object to which the air is blown is An example is a mode in which air is blown over the majority area. In this example, since the object to which the air is blown falls, a sufficient air blowing force is required to move the object in the direction intersecting with the direction of gravity. For this reason, it is preferable to secure the air blowing area as wide as possible to the object to be sprayed, and in this example, the majority area of the projection surface facing the direction of gravity of the object to which air is to be sprayed.

Hereinafter, the present invention will be described in further detail based on the embodiments shown in the attached drawings.
◎ Embodiment 1
-Overall configuration of ore sorting equipment-
FIG. 2 is an explanatory diagram showing the overall configuration of the ore sorting apparatus according to Embodiment 1. As shown in FIG.
In the figure, an ore sorting device 20 has a storage container 21 in which crushed rocks containing ores to be sorted (e.g., gold ore) are stored. A sieve 22 is attached to adjust the size, for example, a maximum diameter of 50 to 75 mm, and a water washing device (not shown) is attached, and the crushed rock is washed with water in the container 21 and passed through the sieve 22 to a predetermined size. It is intended to pass only a range of rock fragments.
In this example, a vibrating feeder 23 is arranged at an angle below the sieve 22 of the container 21, and a belt conveyor 25 is arranged downstream of the vibrating feeder 23 via a guide chute 24. .

In the present embodiment, the belt conveyor 25 has, for example, a conveying belt 26 stretched between a pair of tension rolls 27 and 28 so as to be able to circulate. is a drive roll capable of transmitting, and the conveying belt 26 is circulated.
In this example, the conveying belt 26 is made of a thick wear-resistant belt material (e.g. steel cords, elastic rubber such as ethylene or propylene containing reinforcing materials such as non-woven fabric) capable of conveying pulverized rocks. The surface of the chute 24 is provided with an appropriate amount of frictional resistance so that crushed rocks carried in through the guide chute 24 are not rolled unnecessarily, but are held at appropriate intervals and conveyed. It's becoming
In this example, the belt conveyor 25 is adjusted by the drive motor 29 so as to convey the conveyor belt 26 at a predetermined speed vc.
In FIG. 2, pulverized rock G is placed on the belt conveyor 25 within a predetermined allowable width. (represented by ◯) and defective products Gb (represented by ● in the figure), which are so-called scraps. The details of the criterion for distinguishing the non-defective ore Ga and the defective ore Gb referred to here will be described later.

Further, as shown in FIGS. 2 and 3, the belt conveyor 25 drops the pulverized rock G from the leading end of the portion of the conveying belt 26 stretched over the tension roll 28 at the downstream end in the conveying direction. It is made to fall along the trajectory w.
A camera 30 as an image pickup device is arranged substantially horizontally at a position facing the image pickup position Q1 located in the middle of the fall trajectory w of the pulverized rock G. is provided with one or a plurality of illumination lamps 40 for illuminating the imaging position Q1.
Further, a nozzle array 51, which is one element of the air blowing device 50, is arranged at a portion facing the blowing position Q2 located below the imaging position Q1 in the middle of the fall trajectory w of the crushed rock G.
Furthermore, a sorting container 70 for sorting and storing good ore products Ga and defective ore products Gb to be sorted is installed below the spraying position Q2 on the falling trajectory w of the pulverized rock material G. As shown in FIG.
Reference numeral 80 denotes a control device for sending predetermined control signals to the camera 30, the illumination lamp 40, the air blower 50 and the drive motor 29 to control each element.

<Selection of Conveyor Speed of Belt Conveyor>
In this embodiment, the conveying speed vc of the belt conveyor 25 (specifically, the conveying belt 26) is selected as follows.
In this example, the tension roll 28 positioned on the downstream side in the conveying direction of the belt conveyor 25 has a diameter of d, and the conveying belt 26 is stretched over the tension roll 28 with a diameter of d and is curved in a semicircular cross section. there is
Here, the crushed rock G is placed on and conveyed on a straight portion 26a extending in the horizontal direction of the conveying belt 26 of the belt conveyor 25, and is conveyed horizontally at a portion from the straight portion 26a to the curved portion 26b of the conveying belt 26. released to
At this time, if the conveying speed of the conveying belt 26 is set faster than a predetermined threshold value, the discharge speed of the crushed rock G in the horizontal direction becomes faster, and the crushed rock G is separated from the curved portion 26b of the conveying belt 26. It will fly away. In this case, although the falling trajectory w of the crushed rock G varies due to the difference in particle size (weight), it can be obtained as a relatively stable one. , the flight distance of the crushed rock material G in the horizontal direction is increased, and accordingly, it is necessary to secure an installation space for the camera 30 and the air blowing device 50 at a position sufficiently distant from the belt conveyor 25. There is a concern that the size of the sorting device 20 will be increased.
On the other hand, when the conveying speed of the conveying belt 26 falls below the predetermined threshold value, the crushed rock G is conveyed while being in contact with the conveying belt 26 until it reaches the drop start position corresponding to the tip position of the curved portion 26b of the conveying belt 26. However, if the conveying speed of the conveying belt 26 becomes extremely slow, the crushed rock material G slides at the contact portion with the curved portion 26b of the conveying belt 26, and leaves the conveying belt 26. The falling starting positions of the objects G may vary, or the crushed rocks G which have slid and moved may roll on the curved portion 26b, causing the crushed rocks G to fall off the conveying belt 26 to vary in starting posture. There is a concern that the drop trajectory w of G is likely to become unstable.
Therefore, in the present embodiment, at the curved portion 26b of the conveyor belt 26, the pulverized rock material G draws a falling trajectory w with a curvature close to the curvature of the peripheral surface of the curved portion 26b, and slides at the contact portion with the curved portion 26b. The conveying speed of the conveying belt 26 is selected to be a predetermined conveying speed vc so that the sheet is conveyed without moving.
A specific selection example will be described in detail in Examples.

<Camera>
In this embodiment, as shown in FIGS. 2 to 4, the camera 30 is composed of a line sensor in which imaging elements 31 such as monochrome CCDs are arranged in the horizontal direction at predetermined pixel density intervals k. The image of crushed rock G falling at position Q1 is sequentially captured.
In this example, the camera 30 has an imaging position Q1 which is vertically h1 below the horizontal position along the straight portion 26a of the conveying belt 26 of the belt conveyor 25, and the crushed rock G crossing the imaging position Q1. Imaging information including the projected area and the gradation information of the crushed rock material G is acquired. In this example, the object to be sorted is gold ore, and gold, which is the target mineral, appears in a nearly white image in the monochrome image. The ratio occupied by the image portion becomes the content ratio of the target mineral, and it is possible to determine whether the ore is good or bad depending on whether or not this content ratio is equal to or greater than a predetermined threshold.

<Air blower>
In this embodiment, the nozzle array 51, which is one element of the air blowing device 50, is arranged vertically from a horizontal position along the straight portion 26a of the conveyor belt 26 of the belt conveyor 25, as shown in FIGS. A plurality of spray nozzles 52 are arranged in a substantially horizontal direction at predetermined pitch intervals p, and the air from each spray nozzle 52 is arranged so as to face the lower spray position Q2 by h2 (h2>h1). The spraying operations are controlled on and off by the corresponding solenoid valves 53 .
Here, the inner diameter u and the pitch interval p of the blowing nozzle 52 may be selected as appropriate, but from the viewpoint of maintaining good air blowing to the crushed rock G, the minimum size of the crushed rock G ( 50 mm in this example), and for example, it is set to about 8 to 20 mm (in this example, all are around 10 mm).
In this example, assuming that the nozzle array 51 has, for example, n spray nozzles 52 arranged in a line, the electromagnetic valves 53 corresponding to the respective spray nozzles 52 are divided into a plurality of stages (four stages in this example). It is constructed as a solenoid valve unit 54 in which n/4 pieces are arranged in each. An air tank 55 storing compressed air pressurized to a predetermined pressure (for example, 0.7 to 1.0 MPa) is provided, and the air tank 55 is connected to the flow path of each solenoid valve 53. , the compressed air of the air tank 55 is supplied to the corresponding blowing nozzle 52 along with the ON operation of the corresponding solenoid valve 53, and the blowing operation of the air by the blowing nozzle 52 is performed.
An on/off signal is generated from a solenoid valve drive circuit 56 to each solenoid valve 53 , and a control signal from a control device 80 is sent to the solenoid valve drive circuit 56 .
In particular, in this example, when the control device 80 determines that the pulverized rock G is a non-defective ore Ga from the result of imaging by the camera 30, the control device 80 responds at the timing when the non-defective ore Ga passes the spraying position Q2. The corresponding solenoid valve 53 is turned on, and the air blowing operation is performed by the corresponding blowing nozzle 52 .

<Sorting container>
In this embodiment, as shown in FIGS. 2 and 3, the sorting container 70 has a housing area for the good ore Ga and the bad ore Gb (in this example, the first h3) downward from the spraying position Q2 in the vertical direction. The second housing region R1 is used as a housing region for non-defective products Ga, and the second housing region R2 is used as a housing region for defective products Gb. has a partition wall 71 that partitions the
Here, when the non-defective ore Ga is blown along with the air blowing operation of each of the spray nozzles 52, the non-defective ore Ga falls along a trajectory w1 different from the trajectory w2 of the defective ore Gb. However, as the drop trajectory w1 of the non-defective ore Ga, it is sufficient that the protruding amount j from the partition wall 71 is sufficiently ensured so that the non-defective ore Ga is surely stored in the predetermined storage area R1. , the distance h3 from the spraying position Q2 to the sorting container 70 may be selected so as to ensure a sufficient protruding amount j.

－Ore sorting process－
In the present embodiment, the control device 80 has an ore sorting processing program (see FIG. 5) capable of sorting good ore Ga and defective ore Gb from crushed rock G. By executing this program, , sorting good ore Ga and defective ore Gb.
Now, as shown in FIG. 5, when a start switch (not shown) is turned on, the ore sorting device 20 is activated, and the crushed rock G is washed with water and passed through a sieve 22 in a storage container 21 to obtain a size within a predetermined range. After squeezing, the rock crushed material G is fed onto the belt conveyor 25 via the vibrating feeder 23 and the guide chute 24 .
At this time, the belt conveyor 25 is being conveyed at a predetermined conveying speed vc, and the pulverized rock material G on the belt conveyor 25 is conveyed at the predetermined conveying speed vc and stretched downstream of the belt conveyor 25 in the conveying direction. It falls while drawing a fall trajectory w having a curvature close to the curvature of the peripheral surface of the curved portion 26b of the conveying belt 26 along the support roll 28 .

Then, when the crushed rock G passes through the imaging position Q1, the camera 30 picks up an image of the crushed rock G under illumination light from the illumination lamp 40 .
In this state, the control device 80 discriminates whether the crushed rock G is a non-defective ore Ga or a defective ore Gb.
As a discrimination method used in this example, as shown in FIG. After calculating the projected area Sb of , the non-defective ore Ga and the defective ore Gb are discriminated from the following equation.
(Sa/Sb)≧α (Formula 1)
Here, α indicates the percentage (for example, 30%) that allows the ore to be non-defective Ga.
In this example, since quartz containing gold, which is the target mineral, is white, Sa is calculated based on the grayscale information (corresponding to white) of the image captured by the camera 30 . On the other hand, since minerals other than the target mineral are gray or black, Sb can be calculated by calculating the total projected area of the pulverized rock material G containing Sa. Specifically, the control device 80 obtains an 8-bit monochrome grayscale image (256 grayscales in this example) from the image pickup result (projected area, grayscale information) by the camera 30, and converts it into a three-valued image. After (white area, gray area, black area), it is determined whether or not the occupancy ratio of the white area (the occupancy ratio of the target mineral) is equal to or greater than the threshold α. In this case, the black area is the background, the white area and the gray area are the whole ore as the crushed rock material G, and the white area is the target mineral gold, so Sa/Sb=(white area)/(white area) + gray area).
Then, on the basis of the calculation result of (Formula 1), for example, as shown in case 1 of FIG. do.
Further, as shown in case 2 of FIG. 6(b), under the condition of (Sa/Sb)<α (condition of low mineral content), the crushed rock G is determined to be a defective ore Gb.
Furthermore, as shown in case 3 of FIG. 6(c), when Sa is approximately 0, the rock pulverized material G is determined to be a defective ore Gb.

Next, when the control device 80 determines, for example, that the crushed rock G is a non-defective ore Ga based on the imaging result of the camera 30, the control device 80 determines that the non-defective ore Ga passes the spraying position Q2. The corresponding blowing nozzle 52 blows air (Air) to the non-defective ore Ga.
At this time, although the falling speed of the good ore Ga differs between the imaging position Q1 and the spraying position Q2, the distance between the two is constant, so the good ore Ga passing through the imaging position Q1 reaches the spraying position Q2. The falling time until the air is dropped is constant, and based on this, the air blowing operation timing of the blowing nozzle 52 is determined.
In this example, as shown in FIG. 5, the control device 80 sets the air blowing conditions to is calculated, a control signal is generated based on this air blowing condition.

Here, an example of a method of calculating the conditions for blowing air by the corresponding blowing nozzles 52 will be described.
In this example, as the air blowing conditions, the size of the ore and the elapsed time from the imaging position Q1 to the spraying position Q2 are calculated based on the imaging result of the camera 30, and the air blowing operation by the corresponding blowing nozzle 52 is performed. Calculation of the air blowing time according to the start time of the ore and the size of the ore.
(1) Speed and time of ore at imaging position Q1 and spraying position Q2 In this example, as shown in FIG. The spraying position Q2 is set vertically downward by h2 (h2>h1) from the ore drop start position.
These pieces of information h1 and h2 are preliminarily input into the memory of the control device 80, and the control device 80 uses these pieces of information h1 and h2 to determine the velocity v1 at the imaging position Q1 and the elapsed time t1 from the drop start position. , ore velocity v2 at the spraying position Q2, the elapsed time t2 from the drop start position, and the elapsed time Δt (t2-t1) from the imaging position Q1 to the spraying position Q2 are calculated and recorded in advance. In addition, in the following formulas, g indicates gravitational acceleration.

v1=√(2.g.h1) (Formula 1)
v2=√(2.g.h2) (Formula 2)
Since h1=(1/2)g·t1 ² , t1=√(2·h1/g) (Formula 3)
Since h2=(1/2)g·t2 ² , t2=√(2·h2/g) (Formula 4)
Δt=t2−t1=√(2·h2/g)−√(2·h1/g) (Formula 5)
Therefore, it is understood that the ore reaches the spraying position Q2 when Δt has elapsed after reaching the imaging position Q1, and the speed v at that time is √(2·g·h2).
In this state, the control device 80 may calculate the elapsed time from the imaging position Q1 to the spraying position Q2 of the ore, and start the air spraying operation by the spray nozzle 52 .
In this example, the method of calculating Δt using (Equation 5) was adopted, but it is not limited to this. The ore velocity v1 at the position Q1 may be used for simple calculation by the following (Equation 5').
Δt=(h2−h1)/v1 (Formula 5′)

(2) Size of Ore In this example, as shown in FIG. 7B, the ore is photographed by the camera 30 at the imaging position Q1, and a projected image facing the direction of gravity is obtained. At this time, as described above, it is determined whether the ore is a non-defective product Ga or a defective product Gb based on the density difference information of the projected image of the ore. The highest end position y _max and the lowest end position y _min of y are determined, and the difference L(y _max −y _min ) between the two is calculated. At this time, in order to calculate the vertical dimension L of the projected image of the ore, for example, the number of pixels in the vertical direction of the projected image of the ore sample whose dimensions are measured in advance (the vertical dimension is L0) is Assuming that n0, if the number of pixels n in the vertical direction of the projection image of the ore to be photographed is counted, the vertical dimension L of the ore can be calculated by the following (Equation 6).
L=(n/n0)·L0 (Formula 6)
For example, if L0 is 0.05 [m] and the number of pixels n0 is 2500, for example, if the number of pixels n at a location corresponding to the vertical dimension L of the projected image of the ore measured is 2000, L is It is calculated as 0.04 [m].
In particular, in this example, since the camera 30 is a line camera using a line sensor, the imaging rate f [Hz] (in the case of a line camera, Since the line rate for each line) is constant, the pixel resolution B [m/pixel] can be calculated by B=v1/f [m/pixel]. Therefore, if the number of pixels between the uppermost position y _max in the vertical direction y and the lowermost position y _min in the projected image of the ore is n [pixels], the vertical dimension L of the ore is given by the following (formula 6').
L = B · n ...... (Equation 6')

(3) Adjustment of Air Spraying Time by Spray Nozzle In the calculation process of (1) described above, the start point of air spraying by the spray nozzle 52 and the speed v2 of the ore at the spraying position Q2 are recognized. In the calculation process of (2), the vertical dimension L of the projected image of the ore is recognized as a parameter of the size of the ore.
In this example, the control device 80 causes the blowing nozzle 52 to blow air only while the ore having the dimension L passes the blowing position Q2 of the blowing nozzle 52 at the speed v2, so that the following (Equation 7) , the air blowing time t _air by the blowing nozzle 52 is calculated.
t _air =L/v2 (Formula 7)
Therefore, the control device 80 starts the air blowing operation from the time when the blowing nozzle 52 starts blowing air, continues the air blowing operation for the calculated air blowing time t _air , and then stops the air blowing operation. good.
By performing such air blowing control, it is possible to blow air only to the ore to which air should be blown (in this example, the good ore Ga), and to blow the air only to the ore that is not to be sprayed (in this example, the defective ore). Since the air from the spray nozzle 52 is rarely blown to the non-defective product Gb), the ore sorting rate is maintained at a good level.

Now, when the good ore Ga is dropped toward the nozzle array 51, the control device 80 recognizes the drop movement position of the good ore Ga passing the spraying position Q2, and the time shown in FIG. As the process progresses (t=Δt→6Δt), the air blowing operation is performed by the blowing nozzle 52 at the position corresponding to the non-defective ore Ga. In FIG. 8(b), the blowing nozzles 52 marked with .smallcircle.
When such an air blowing operation is performed by the blowing nozzle 52, the compressed air is blown over substantially the entire projection surface facing the gravitational direction of the non-defective ore Ga, and the partition wall 71 of the sorting container 70 is blown. , and is accommodated in the second accommodation area R2 through a drop trajectory w2 having a sufficient protrusion amount j. In this example, the compressed air is blown to almost the entire area of the projection plane facing the direction of gravity of the non-defective ore Ga. Ore sorting operations can be performed well.
Since the air blowing operation by the blowing nozzle 52 is not performed on the defective ore Gb, the defective ore Gb passes through the second drop trajectory w2 that continues to the predetermined drop trajectory w. It is housed in the housing area R2.

In the present embodiment, as shown in FIG. 8A, the spray nozzle 52 rotates in the M direction and blows air onto the falling good ore Ga. However, when the upper side of the non-defective product Ga is tilted so that the upper side is closer to the spray nozzle 52 side than the lower side, when the air from the spray nozzle 52 is blown to the non-defective product Ga, the non-defective product Ga has a horizontal direction. In addition to the upward blowing force component Fh, an upward blowing force component Fv is applied. At this time, the upward blowing force component Fv acts on the non-defective product Ga of the ore, so that a resistance force is generated when the non-defective product Ga falls. It is possible to secure a large flight distance of the non-defective product Ga accompanying the spraying.
Furthermore, in the present embodiment, the ore, which is the rock pulverized material G that has fallen from the belt conveyor 25, is subject to gravitational acceleration as it falls, so that it scatters in the falling direction. Therefore, the amount of the pulverized rock G supplied onto the belt conveyor 25 may be varied to the extent that the pulverized rock G does not overlap. It is not necessary to supply the rock crushed material G in a state.

◎Embodiment 2
FIG. 9 is an explanatory diagram showing a main part of an ore sorting apparatus according to Embodiment 2. FIG.
In the figure, the ore sorting apparatus 20 has a basic configuration substantially similar to that of the first embodiment, but has an air blower 50 different from that of the first embodiment. Components similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed descriptions thereof are omitted here.
In this example, the air blowing device 50 has two upper and lower nozzle arrays 51a and 51b, and each of the nozzle arrays 51a and 51b has spray nozzles 52 arranged at predetermined pitch intervals.
In the present embodiment, the upper and lower nozzle arrays 51a and 51b are configured such that, as shown in FIG. 10(a), air is simultaneously blown by the spray nozzles 52 in each row (simultaneous impact method). Alternatively, as shown in FIG. 10(b), the air blowing operation of the blowing nozzles 52 in each row may be performed with a time difference (time difference impact method).
Further, in this example, when the good ore Ga is dropped facing the nozzle arrays 51a and 51b, the control device 80 recognizes the drop movement position of the good ore Ga passing the spraying position Q2. , with the lapse of time (t=Δt→6Δt) in FIG. 10(c), the air blowing operation is performed by the blowing nozzle 52 at the position corresponding to the non-defective ore Ga. In FIG. 10(c), the blowing nozzles 52 indicated by ◯ indicate the state in which the air blowing operation is not performed, and the blowing nozzles 52 indicated by ● indicate the state in which the air blowing operation is performed.
When such an air blowing operation is performed by the blowing nozzle 52, compared with the first embodiment, the non-defective ore Ga is blown with about twice as much compressed air, and further from the partition wall 71 of the sorting container 70. It is accommodated in the first accommodation area R1 through a drop trajectory w1 having a sufficient pop-out amount j.

◎Modifications In this embodiment, the air blowing device 50 employs two nozzle arrays 51a and 51b arranged vertically, but is not limited to this. , three upper and lower nozzle arrays 51a to 51c, and spray nozzles 52 are arranged at predetermined pitch intervals in each of the nozzle arrays 51a to 51c.
In this modification, the nozzle arrays 51a and 51b in the three upper and lower stages simultaneously carry out air blowing operations by the blowing nozzles 52 in each row (simultaneous blowing method), as shown in FIG. 11(a), for example. Alternatively, as shown in FIG. 11(b), the air blowing operation of the blowing nozzles 52 in each row may be performed with a time difference (time difference impact method).
Furthermore, as shown in FIG. 11(c), the spray nozzles 52 in each row may be arranged in parallel to carry out a spraying operation using parallel airflows (parallel impact method), or FIG. 11(d). 3, the spray nozzles 52 in each row may be arranged at an angle so as to concentrate on one point, and the air flow concentrated on one point may be used to perform the spraying operation (single-point concentrated impact method).
It goes without saying that the air blowing device 50 may employ a nozzle array with four or more vertical stages.

◎ Example 1
In this example, the performance of the ore sorting apparatus according to the first embodiment is evaluated.
In this embodiment, as shown in FIG. 12(a), crushed rock material G containing ore is let out and dropped from the end of the belt conveyor 25 in the conveying direction.
Here, as the crushed rock material G, one having a shape that is easy to roll was selected.
In FIG. 12(a), A is a position 0.5 m below the conveying surface of the crushed rock material G of the belt conveyor 25, and B is a position 0.5 m below the A position.
tf is the drop time (fall distance) from A to B, x is the amount of jumping out from the tip position of the belt conveyor 25 to B (when dropped by 1m), θ is the amount of rotation from A to B ( 100 ms), and each experiment was performed multiple times (N=10 times).
In this example, the tension roll diameter of the belt conveyor 25 is 200 mm, and the conveying speed of the belt conveyor 25 is 1 m/s.
In Comparative Example 1, the samples were dropped directly from the vibrating feeder 23 without using the belt conveyor 25 . However, the vibrating condition of the vibrating feeder 23 is 60 Hz, and the conveying speed is 8 m/min. is.
The results of comparison items for Example 1 and Comparative Example 1 are shown in FIG. 12(b).
It is understood that Example 1 has less variation than Comparative Example 1 in all the comparison items, and the falling behavior of the pulverized rock G is stable.

In Example 1, the experiment was performed 20 times at each conveying speed under the condition that the conveying speed of the belt conveyor 25 was changed. The results shown in FIG. 15 were obtained.
However, the variation in drop time was set to 700 mm to 1200 mm. In addition, the head was set to 1200 mm for the variation in the amount of projection. Furthermore, the variation in the amount of rotation was defined as the drop between 700 mm and 1200 mm.
FIG. 13 shows variations in falling time.
Here, "the amount of biting is 0" means that the crushed rock material is conveyed by the belt conveyor so that it is conveyed while drawing a drop trajectory along the curvature of the peripheral surface of the curved portion of the conveying belt that is stretched over the tension roll. It corresponds to the case where the speed is selected, and "no biting" means that the crushed rock is conveyed by the belt conveyor so that it is conveyed by drawing a curvature trajectory less than the curvature of the curved portion that is stretched over the tension roll. It corresponds to the case where the speed is selected, and "bite" means that the conveying speed of the belt conveyor is adjusted so that the pulverized rock is conveyed while drawing a locus with a curvature larger than the curvature of the curved portion that is stretched over the tension roll. Corresponds to the selected equivalent.
According to the figure, it is understood that in the case of "no bite", the variation in the drop time is smaller than in the case of "bite". 0” (1.04 m/s in FIG. 13), the variation in drop time increases. This means that if the conveying speed of the belt conveyor is extremely slowed down, the crushed rock material slides and moves at the contact area with the curved part of the belt conveyor when the crushed rock material is let out and falls from the curved part of the belt conveyor. This is presumed to be caused by variations in the drop start position and drop start posture from the belt conveyor.
FIG. 14 shows variations in the protruding amount of the crushed rock, and FIG. 15 shows variations in the amount of rotation of the crushed rock. Compared to the case of "with bite", it is understood that variations in the amount of protrusion and the amount of rotation of the crushed rock are small. It is understood that the larger the distance, the greater the variation in the amount of protrusion and the amount of rotation.
In Example 1, the tension roll diameter was changed from 200 mm to 300 mm, and the conveying speed of the belt conveyor 25 was changed. When variation in time, variation in amount of protrusion, and variation in amount of rotation were investigated, almost the same tendency as in the case of the tension roll having a length of 200 mm was observed.

In addition, when the trajectory of the crushed rock material in the portion stretched over the tension roll of the belt conveyor (diameter of the tension roll: 200 mm in this example) was examined by changing the conveying speed of the belt conveyor, the results shown in FIG. 16 were obtained. was gotten.
According to the figure, when the conveying speed of the belt conveyor is 1 m/s (a speed substantially corresponding to "bite amount 0"), the falling trajectory of the crushed rock material substantially corresponds to the curvature of the curved portion of the belt conveyor. It is understood that the falling trajectory is stabilized. Also, when the conveying speed of the belt conveyor is set to, for example, 1.2 m/s, the falling trajectory of the crushed rock material becomes less than the curvature of the curved portion of the belt conveyor, but changes to a trajectory with a curvature close to the curvature of the curved portion of the belt conveyor. It is understood that Even in the case of "bite", if the biting amount is close to 0 (for example, the conveying speed of the belt conveyor is set to 0.8 m/s), the falling trajectory of the crushed rock material will follow the curvature of the curved part of the belt conveyor. It is understood that the trajectories are close to each other.
Furthermore, when the falling trajectory of the rock crushed material in the portion stretched over the tension roll of the belt conveyor (diameter of the tension roll: 300 mm in this example) was examined by changing the conveying speed of the belt conveyor, the results shown in Fig. 17 were obtained. was gotten.
According to the figure, when the conveying speed of the belt conveyor is 1.2 m/s (a speed substantially corresponding to "bite amount 0"), the falling trajectory of the crushed rock material substantially corresponds to the curvature of the curved portion of the belt conveyor. It is understood that the falling trajectory is stabilized. Also, when the conveying speed of the belt conveyor is set to 1.4 m/s, for example, the falling trajectory of the crushed rock material becomes less than the curvature of the curved portion of the belt conveyor, but changes to a trajectory with a curvature close to the curvature of the curved portion of the belt conveyor. It is understood that Even in the case of "bite", if the biting amount is close to 0 (for example, the conveying speed of the belt conveyor is set to 1.0 m/s), the falling trajectory of the rock crushed material does not match the curvature of the curved part of the belt conveyor. It is understood that the trajectories are close to each other.
Therefore, in the case of "no bite", that is, under the speed condition exceeding the speed of the belt conveyor corresponding to "bite amount 0", the falling trajectory of the crushed rock is stable, but the speed of the belt conveyor should be set high. If it is too much, the amount of movement of the crushed rock material in the horizontal direction becomes large, so from the viewpoint of reducing the amount of movement of the crushed rock material in the horizontal direction, the belt conveyor speed corresponding to "biting amount 0" It is preferable to choose a speed close to .
In addition, in the case of "bite", the falling trajectory of the crushed rock becomes a trajectory close to the curvature of the curved portion of the belt conveyor in the vicinity of "the amount of bite is 0", but depending on the shape of the crushed rock, the crushed rock may not be crushed. Since there is a possibility that the variation in the falling time, the amount of protrusion, or the amount of rotation of the object may increase, when selecting the conveying speed of the belt conveyor, at least except for the case of "bite", "bite amount 0" or "no bite" is preferably selected as the permissible range in the vicinity of "bite amount 0".

◎ Example 2
This embodiment is an embodiment of the ore sorting apparatus according to Embodiment 1. As shown in FIG. 550 mm and 750 mm, respectively, to examine the effect on the ore sorting performance (in this example, the flight distance from the partition wall of the sorting container). Incidentally, in this embodiment, h3=500 mm.
FIG. 18 shows the result of 160 times each of 20 types of crushed rocks G, 8 times each of ore, which is configured to perform air blowing operation by the blowing nozzle 52 for the mode of h2=550 mm.
FIG. 19 shows the result of 160 times of 8 times each of 20 types of rock crushed material G, ore, which is configured to perform air blowing operation by the blowing nozzle 52 for the mode of h2 = 750 mm. .
18 and 19, Pz indicates the drop position of the ore when the air blowing operation by the blow nozzle 52 is not performed.

According to FIGS. 18 and 19, the air blowing operation method at a head of 550 mm has an overall flight distance (projection amount) j greater than that of the air blowing operation method at a head of 750 mm. is understood.
Here, when h2=550 mm, the distribution of the amount of ore rotation up to the spraying position Q2 was examined, and the results shown in FIG. 20 were obtained.
According to FIG. 20, the amount of rotation of the ore was 95 degrees in the median within the range of 40 degrees to 145 degrees.
Further, when h2=750 mm, the distribution of the amount of ore rotation up to the spraying position Q2 was examined, and the results shown in FIG. 21 were obtained.
According to FIG. 21, the amount of rotation of the ore was 110 degrees in the median of the spread from 50 degrees to 165 degrees.
In this way, the flying distance (projection amount) j is increased overall in the mode of h2 = 550 mm because the amount of rotation of the ore is optimized, and the blowing nozzle 52 blows air upward to the ore. It is presumed that the reason for this is that the blowing force component of 1 acts effectively, and the falling speed of the ore slows accordingly.

◎ Example 3
In Example 3, the ore sorting apparatus according to Embodiment 2 is embodied, and the ore sorting performance is evaluated by changing the air blowing conditions of the air blowing device 50 .
In this example, ore sorting performance (flying distance j) was evaluated for the following four modes.
(1) Single row spray nozzle Air pressure 0.7 MPa
(2) Two-row spray nozzle Air pressure 0.7 MPa
Simultaneous impact method (3) 2-row spray nozzle Air pressure 1.0 MPa
Simultaneous impact method (4) 2-row spray nozzle Air pressure 1.0 MPa
Time difference impact method For comparison, (1) was conducted for a single row spray nozzle method in a similar manner.

When each case was measured ten times, the results shown in FIG. 22 were obtained.
It is understood that the ore sorting performance is higher when the air blowing operation is performed by the two-row blowing nozzle system than by the one-row blowing nozzle system. be.
It is also understood that in the two-row spray nozzle system, the higher the air pressure, the greater the flying distance j.
Furthermore, it is understood that, in the two-row spray nozzle system, the flying distance j is greater in the staggered impact system than in the simultaneous impact system.
In FIG. 22, Pz indicates the drop position of the defective ore under the condition that the air blowing operation is not performed by the blowing nozzle.

In Example 3, the number of spray nozzle rows and air pressure were changed, and the inclination angle from the spray position Q2 to the drop position (flying distance) of the ore was taken as the drop angle, and measurements were made 30 times for each case. The results shown in 23 were obtained.
According to the figure, it can be understood that the two-row spray nozzle method can obtain a larger drop angle than the one-row spray nozzle method, if the air pressure is the same.
In addition, it is understood that in the one-row spray nozzle system and the two-row spray nozzle system, the drop angle is larger when the air pressure is 1.0 MPa than when the air pressure is 0.7 MPa.
In FIG. 23, the theoretical increase rate is the ratio of the theoretical air blowing force in each case when the air blowing force in the mode of air pressure 0.7 MPa in the single row blowing nozzle system is set to 1. show.

1 rock pulverized product 1a non-defective ore 1b defective ore 2 supply device 3 imaging device 4 discriminating device 5 air blowing device 6 belt-shaped carrier 7 driving device 8 sorting container 9a tension roll A supply process B imaging process C sorting process

Claims (7)

When sorting out non-defective ore products determined in advance by the content ratio of the target mineral from the rock pulverized product,
A belt-shaped carrier that circulates across a plurality of tension rolls and carries the crushed rock material is used to convey the crushed rock material in a predetermined parabola from the downstream end in the conveying direction of the belt-shaped carrier. A supply step of supplying so as to drop on a drop trajectory of a shape;
an image capturing step of capturing an image of the pulverized rock supplied in the supplying step from a direction intersecting with the direction of gravity in the middle of the drop trajectory;
Based on the imaging result of the imaging step, the ore is sorted into non-defective ore from the rock pulverized material that has undergone the imaging step, and any one of A sorting step of blowing air toward one of the objects from a direction intersecting the direction of gravity;
with
In the supplying step, the pulverized rock falls along the curvature of the curved portion at the curved portion that is stretched over the tension roll located at the downstream end in the conveying direction of the belt-shaped carrier. , and the ore sorting method is characterized in that the ore is conveyed in a state of zero biting without slipping at the contact portion with the curved portion . When sorting out non-defective ore products determined in advance by the content ratio of the target mineral from the rock pulverized product,
A belt-shaped carrier that circulates across a plurality of tension rolls and carries the crushed rock material is used to convey the crushed rock material in a predetermined parabola from the downstream end in the conveying direction of the belt-shaped carrier. A supply step of supplying so as to drop on a drop trajectory of a shape;
an image capturing step of capturing an image of the pulverized rock supplied in the supplying step from a direction intersecting with the direction of gravity in the middle of the drop trajectory;
Based on the imaging result of the imaging step, the ore is sorted into non-defective ore from the rock pulverized material that has undergone the imaging step, and any one of A sorting step of blowing air toward one of the objects from a direction intersecting the direction of gravity;
with
In the supplying step, at a curved portion that is stretched over the tension roll located at the downstream end in the conveying direction of the belt-shaped carrier, the pulverized rock material is distributed along a curvature less than the curvature of the peripheral surface of the curved portion . ore sorting method, characterized in that the ore sorting method is characterized in that the ore is conveyed in a state in which it draws a falling trajectory and does not slip at the contact portion with the curved portion and does not bite into the portion. An ore sorting device for sorting out non-defective and defective ores predetermined by the content ratio of target minerals from pulverized rocks,
a supply device for supplying the rock crushed material so as to drop along a predetermined parabolic drop trajectory;
an image pickup device for picking up an image of the pulverized rock supplied by the supply device from a direction intersecting with the direction of gravity in the middle of the fall trajectory;
a discriminating device that discriminates a non-defective ore from the rock pulverized material based on the result of imaging by the imaging device;
Based on the discrimination result by the discriminating device, the trajectory of the good ore that has fallen below the imaging position of the imaging device is different from that of the defective ore. an air blowing device for blowing air from a direction;
with
The supply device includes a belt-shaped carrier that is stretched over a plurality of tension rolls and circulates to transport the pulverized rock material, and the tension roll positioned at the downstream end of the belt-shaped carrier in the conveying direction. The crushed rock is conveyed in a state of zero biting without slipping at the contact portion with the curved portion while drawing a falling trajectory along the curvature of the peripheral surface of the curved portion. and a driving device for driving the belt-like conveying body at a predetermined conveying speed. An ore sorting device for sorting out non-defective and defective ores predetermined by the content ratio of target minerals from pulverized rocks,
a supply device for supplying the rock crushed material so as to drop along a predetermined parabolic drop trajectory;
an image pickup device for picking up an image of the pulverized rock supplied by the supply device from a direction intersecting with the direction of gravity in the middle of the fall trajectory;
a discriminating device that discriminates a non-defective ore from the rock pulverized material based on the result of imaging by the imaging device;
Based on the discrimination result by the discriminating device, the trajectory of the good ore that has fallen below the imaging position of the imaging device is different from that of the defective ore. an air blowing device for blowing air from a direction;
with
The supply device includes a belt-shaped carrier that is stretched over a plurality of tension rolls and circulates to transport the pulverized rock material, and the tension roll positioned at the downstream end of the belt-shaped carrier in the conveying direction. In the curved portion that is stretched over the curved portion , the crushed rock falls along a curvature less than the curvature of the peripheral surface of the curved portion, and does not slip at the contact portion with the curved portion and does not bite. and a driving device for driving the belt-shaped conveying body at a predetermined conveying speed so that the ore is conveyed, with an allowable range of a biting amount near zero . In the ore sorting apparatus according to claim 4,
The ore sorting apparatus, wherein the driving device selects a conveying speed having an increase of less than 20% with respect to the conveying speed when the biting amount is 0 as the conveying speed of the belt-shaped conveying body. In the ore sorting device according to claim 3 or 4 ,
The discriminating device is characterized by extracting gradation information attributed to the ore from the imaging result of the crushed rock, and discriminating that the ore is a non-defective product when the ratio of the gradation information is equal to or higher than a predetermined threshold value. and ore sorting equipment. In the ore sorting device according to claim 3 or 4 ,
The discriminating device calculates the air blowing start time for the ore, which is the air blowing target, and the projected area of the ore, which is the air blowing target, facing the direction of gravity based on the imaging result by the imaging device. 1. An ore sorting apparatus characterized by adjusting the start of air blowing operation and air blowing time by said air blowing device.

Images