Manufacturing device and manufacturing method

Abstract

To provide a manufacturing device that can manufacture at least two kinds of granular objects having different required grain size in a single line.SOLUTION: A manufacturing device 1 includes a crusher for crushing supplied raw material crushed stones, and at least two classifiers for classifying crush processed products crushed by the crusher in sequence. The classifier includes a first classifier for classifying the crush processed products into a size exceeding a first grain size d1 and a size smaller than or equal to the first grain size d1, and a second classifier for classifying the first classification processed product classified into a size smaller than or equal to the first grain size d1 by the first classifier into a size exceeding a third grain size d3 and a size smaller than or equal to the third grain size d3.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a production apparatus and a production method suitable for producing a plurality of granular materials having different required particle sizes. [Background technology]

[0002] For example, crushed limestone sand, which is a raw material for concrete, and sulfur dioxide (SO 2 ) can be produced from limestone. For example, according to JIS A 5005, crushed limestone sand for concrete is 5 mm (5000 μm) or less, and calcium carbonate powder for desulfurization is, for example, several tens of μm or less. Thus, there is a difference in the particle size required between crushed limestone sand for concrete and calcium carbonate powder for desulfurization, and this difference is large. As such, the range of particle size required for crushed limestone sand for concrete and calcium carbonate powder for desulfurization is different, so it is not easy to produce crushed limestone sand for concrete and calcium carbonate powder for desulfurization on the same production line. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-253982 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, crushed sand is produced by crushing rocks, and fine powder generated during the production of crushed sand is classified and then collected by a dust collector. Since the fine powder is considered to cause a deterioration in the quality of the crushed sand, it is classified and separated to be removed from the crushed sand product. Therefore, although the crushed limestone sand for concrete and the calcium carbonate powder for desulfurization are obtained from the same raw material, the line for producing the crushed limestone sand for concrete and the line for producing the calcium carbonate powder for desulfurization are generally constructed separately. If crushed limestone sand for concrete and calcium carbonate powder for desulfurization, which are made from the same raw materials, are produced on separate lines, the costs of operating and maintaining the separate lines, as well as the labor costs, will be significant.

[0005] In view of the above, an object of the present invention is to provide a production apparatus capable of producing at least two types of granular materials having different required particle sizes, such as crushed limestone sand for concrete and calcium carbonate powder for desulfurization, on a single line. [Means for solving the problem]

[0006] The production apparatus of the present invention comprises a crusher that crushes raw crushed stone supplied thereto, and at least two classifiers that successively classify the crushed material crushed by the crusher. The classifiers comprise a first classifier that classifies the crushed material into sizes exceeding a first particle size d1 and sizes equal to or less than the first particle size d1, and a second classifier that classifies the classified material classified by the first classifier into sizes equal to or less than the first particle size d1 into sizes exceeding a third particle size d3 and sizes equal to or less than the third particle size d3.

[0007] In the production apparatus of the present invention, the crusher preferably includes at least one roll, the first classifier is a vibrating sieve, and the second classifier preferably includes an air separator that performs dry classification.

[0008] The production apparatus of the present invention preferably includes a first return path for transporting the second classified product, which has been classified into particles having a size exceeding the first particle size d1, from the first classifier to the crusher.

[0009] In the production apparatus of the present invention, the crusher is preferably a double roll crusher having two driven rolls, the two rolls being adjacent to each other, and the distance between the two rolls being adjustable.

[0010] In the production apparatus of the present invention, the first classifier is preferably a vibrating sieve, and the second classifier includes a second air separator and a first air separator located upstream of the second air separator, and the first air separator dry-classifies the first classified product classified by the vibrating sieve to a size equal to or less than a first particle size d1 into a size exceeding a second particle size d2 and a size equal to or less than the second particle size d2, and the second air separator dry-classifies the third classified product classified by the first air separator to a size equal to or less than the second particle size d2 into a size exceeding a third particle size d3 and a size equal to or less than the third particle size d3.

[0011] The production apparatus of the present invention preferably includes a first return path for transporting the second classified material, which has been classified to a size exceeding the first particle size d1, from the vibrating sieve to the crusher, and a second return path for transporting the fourth classified material, which has been classified to a size exceeding the third particle size d3, from the second air separator to the crusher.

[0012] The production method of the present invention includes a first step of crushing the supplied limestone, a second step of classifying the limestone crushed in the first step into a size exceeding a first particle size d1 and a size equal to or less than the first particle size d1, and a fourth step of classifying the limestone crushed sand classified into a size equal to or less than the first particle size d1 in the second step into a size exceeding a third particle size d3 and a size equal to or less than the third particle size d3, and the limestone crushed sand equal to or less than the first particle size d1 and exceeding the third particle size d3 is used for concrete, and the lime powder equal to or less than the third particle size d3 is used for desulfurization.

[0013] In the production method of the present invention, preferably, crushed limestone sand classified to have a particle size exceeding the first particle size d1 is transported to the first step (20).

[0014] In the production method of the present invention, preferably, sizes exceeding the first particle size d1 are sizes that do not pass through a sieve with a nominal size of 5 mm, and sizes equal to or less than the first particle size d1 are sizes that pass through a sieve with a nominal size of 5 mm, sizes exceeding the third particle size d3 are sizes that do not pass through a metal mesh sieve with a nominal mesh size of 45 μm, and sizes equal to or less than the third particle size d3 are sizes that pass through a metal mesh sieve with a nominal mesh size of 45 μm.

[0015] The production method of the present invention preferably includes a third step of dry classifying the limestone crushed sand classified in the second step to a size equal to or less than the first particle size d1 into a size exceeding the second particle size d2 and a size equal to or less than the second particle size d2, and a fourth step of dry classifying the lime powder classified in the third step to a size equal to or less than the second particle size d2 into a size exceeding a third particle size d3 and a size equal to or less than the third particle size d3.

[0016] In the production method of the present invention, preferably, limestone crushed sand classified to a size exceeding the first particle size d1 is transported to the first step, and lime powder classified to a size exceeding the third particle size d3 is transported to the first step.

[0017] In the production method of the present invention, preferably, sizes exceeding the first particle size d1 are sizes that do not pass through a sieve with a nominal size of 5 mm, sizes equal to or less than the first particle size d1 are sizes that pass through a sieve with a nominal size of 5 mm, sizes exceeding the third particle size d3 are sizes that do not pass through a metal mesh sieve with a nominal mesh size of 45 μm, sizes equal to or less than the third particle size d3 are sizes that pass through a metal mesh sieve with a nominal mesh size of 45 μm, sizes exceeding the second particle size d2 are sizes that do not pass through a metal mesh sieve with a nominal mesh size of 75 μm, and sizes equal to or less than the second particle size d2 are sizes that pass through a metal mesh sieve with a nominal mesh size of 75 μm. Effect of the Invention

[0018] According to the present invention, it is possible to produce crushed limestone sand and, at the same time, produce calcium carbonate powder for desulfurization on the same production line by utilizing the fine powder generated during the production of crushed limestone sand. [Brief description of the drawings]

[0019] [Figure 1] 1 is a diagram showing a configuration of a production device according to a first embodiment of the present invention. [Diagram 2] FIG. 4 is a diagram showing a history of particle size of a product produced by the production apparatus according to the first embodiment. [Diagram 3] FIG. 5 is a diagram showing a configuration of a production device according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a diagram showing a history of particle size of a product produced by the production apparatus according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. This embodiment includes at least a first embodiment and a second embodiment. In the following, the first embodiment will be described first, and then the second embodiment will be described. <First embodiment: see Figs. 1 and 2> As an example, the production apparatus 1 shown in Fig. 1 produces calcium carbonate powder for desulfurization by utilizing powder contained in crushed sand for obtaining crushed limestone sand for concrete. This production apparatus 1 can produce crushed limestone sand for concrete and calcium carbonate powder for desulfurization in a single line. Below, the configuration of the production apparatus 1, the production method by the production apparatus 1, and the effects of the first embodiment will be described in order.

[0021] [Configuration of production equipment 1: See Figure 1] The production apparatus 1 includes a raw material hopper 10, a double roll crusher 20 as a crusher, a vibrating screen 30 as a classifier, a first air separator 40, and a second air separator 50. The production equipment 1 is equipped with a first conveying path 11 connecting the raw material hopper 10 and the double roll crusher 20, a second conveying path 12 connecting the double roll crusher 20 and the vibrating sieve 30, a third conveying path 13 connecting the vibrating sieve 30 and the first air separator 40, and a fourth conveying path 14 connecting the first air separator 40 and the second air separator 50. The production device 1 includes a first recovery path 15 connecting the first air separator 40 and the first recovery area PA1, and a second recovery path 16 connecting the second air separator 50 and the second recovery area PA2. The production device 1 also includes a first return path 17 connecting the vibrating sieve 30 and the first conveying path 11, and a second return path 18 connecting the second air separator 50 and the first conveying path 11.

[0022] [Raw material hopper 10] The raw material hopper 10 stores limestone as a raw material to be supplied to the double roll crusher 20. This limestone is a raw material for producing limestone crushed sand for concrete and calcium carbonate powder for desulfurization. A feeder (not shown) is connected to the raw material hopper 10, and a predetermined amount of limestone is supplied to the double roll crusher 20 via the first conveying path 11 by the feeder. In this embodiment, the limestone as raw material crushed stone RM supplied to the raw material hopper 10 is, for example, of "crushed stone" in type and "2005" in particle size category in "Table 1-Classification by type and particle size" of JIS A 5005.

[0023] [Double Roll Crusher 20] The double roll crusher 20 crushes the supplied raw material crushed stone RM made of limestone to produce limestone crushed sand CS. This process corresponds to the first process in the present invention. The limestone crushed sand CS is supplied to the vibrating screen 30 via the second conveying path 12. The double roll crusher 20 includes a casing 21 having a crushed stone inlet 22, and a first roll 23, a second roll 24, and a hydraulic cylinder 25 provided inside the casing 21. The crushed limestone sand CS corresponds to the crushed product in the present invention. In addition, since the crushed sand, which is the crushed product, inevitably contains powder with a smaller particle size, the crushed sand in the present invention is allowed to contain powder.

[0024] The casing 21 receives the raw crushed stone RM supplied from the raw material hopper 10 at a crushed stone inlet 22 and discharges the crushed limestone sand CS to the second conveying path 12. The first roll 23 and the second roll 24, which are adjacent and rotatable, crush the raw material crushed stone RM supplied to generate limestone crushed sand CS. The first roll 23 and the second roll 24 are arranged so that their rotation axes are parallel to each other. The first roll 23 and the second roll 24 are each connected to a driving source, such as an electric motor (not shown).

[0025] In the present embodiment, the diameters of the first roll 23 and the second roll 24 are, for example, approximately the same dimension. The first roll 23 is rotated at a predetermined rotation speed in a clockwise direction by a driving source, and the second roll 24 is rotated at a predetermined rotation speed in a counterclockwise direction by a driving source. The raw material crushed stone RM supplied from the raw material hopper 10 is crushed by passing between a first roll 23 and a second roll 24 which are rotated at a predetermined rotation speed. It is preferable to control the respective drive sources so that the rotation speeds of the first roll 23 and the second roll 24 are approximately the same. In other words, it is preferable to control the respective drive sources so that the peripheral speeds of the first roll 23 and the second roll 24 are approximately the same. When the peripheral speeds of the first roll 23 and the second roll 24 are approximately the same, the supplied raw material crushed stone RM is less likely to slip on the roll surfaces, and the crushing efficiency of the double roll crusher 20 is improved.

[0026] The hydraulic cylinder 25 presses the second roll 24 in a direction approaching the first roll 23, thereby generating a crushing force for crushing limestone passing between the first roll 23 and the second roll 24. The tip side of the rod 25A of the hydraulic cylinder 25 is pin-connected to the upper end side 26A of the support member 26 that supports the second roll 24. The second roll 24 is swung in an arc shape around the rotation support end 26B of the support member 26 by moving the rod 25A of the hydraulic cylinder 25 forward and backward. When the distance between the rotation support end 26B and the rotation axis of the second roll 24 is the same as the distance between the upper end side 26A and the rotation axis of the second roll 24, a crushing force twice the thrust of the hydraulic cylinder 25 is generated between the first roll 23 and the second roll 24 due to the principle of leverage. Therefore, by providing the support member 26, even if the hydraulic cylinder 25 has a small thrust, it is possible to increase the crushing force generated between the first roll 23 and the second roll 24.

[0027] The crushing capacity of the double roll crusher 20 can be changed by adjusting the distance between the first roll 23 and the second roll 24 and by adjusting the set pressure of the oil supplied to the hydraulic cylinder 25. In addition, the double roll crusher 20 can adjust the size distribution of the limestone crushed by the double roll crusher 20 by adjusting the distance between the first roll 23 and the second roll 24.

[0028] [Vibrating sieve 30: Classification at first particle size d1 (5 mm)] The vibrating sieve 30 classifies the limestone crushed sand CS crushed by the double roll crusher 20 at the first particle size d1, and classifies the limestone crushed sand CS1 having a size equal to or smaller than the first particle size d1 and the limestone crushed sand CS2 having a size larger than the first particle size d1. This step corresponds to the second step of the present invention. The vibrating screen 30 includes a casing 31 and a mesh 33 provided inside the casing 31. The casing 31 includes a crushed stone inlet 32 ​​into which the limestone crushed sand CS from the double roll crusher 20 is fed, a first discharge outlet 34 from which the limestone crushed sand CS1 is discharged, and a second discharge outlet 35 from which the limestone crushed sand CS2 is discharged. The mesh 33 is provided over the entire opening of the casing 31 when the casing 31 is viewed from above. The mesh 33 is also provided at a predetermined angle with respect to the horizontal direction H. The crushed limestone sand CS1 corresponds to the first classified product of the present invention, and the crushed limestone sand CS2 corresponds to the second classified product of the present invention.

[0029] The limestone crushed sand CS supplied to the upper side of the receiving mesh 33 of the casing 31 is classified into limestone crushed sand CS1 which passes through the mesh 33 downward in the vertical direction V by the vibration of the vibrating sieve 30, and limestone crushed sand CS2 which remains on the upper side without passing through the mesh 33. The limestone crushed sand CS1 passing through the mesh 33 is discharged from the first discharge port 34 located at the bottom of the casing 31 and supplied to the first air separator 40. The limestone crushed sand CS2 rolls on the upper side of the mesh 33, which is inclined with respect to the horizontal direction H, by vibrating the casing 31 with a vibration source (not shown), and is discharged from the second discharge port 35 located above the mesh 33. The limestone crushed sand CS2 discharged from the second discharge port 35 is transported via the first return path 17 to the first conveying path 11 connected to the crushed stone inlet 22 of the double roll crusher 20, and is again fed into the double roll crusher 20.

[0030] In this embodiment, the mesh 33 has, as an example, a nominal sieve size of 5 mm as defined in JIS A 5005. The limestone crushed sand CS1 that passes through the mesh 33 having a nominal sieve size of 5 mm satisfies the grain size of the limestone crushed sand standard in JIS A 5005. Therefore, the limestone crushed sand CS1 is used as limestone crushed sand for concrete. The limestone crushed sand CS2 that does not pass through the mesh 33 of the sieve with a nominal size of 5 mm is larger than the standard particle size of limestone crushed sand, and is returned to the double roll crusher 20 for crushing. Here, the size of the limestone crushed sand CS1 that passes through the nominal size of the sieve of 5 mm is equal to or smaller than the first particle size d1, and the size of the limestone crushed sand CS2 that does not pass through the nominal size of the sieve of 5 mm exceeds the first particle size d1. However, when classification is performed on an industrial production scale, it is difficult to clearly distinguish the particle sizes of the limestone crushed sand CS1 and the limestone crushed sand CS2. Therefore, even the limestone crushed sand CS1 that is equal to or smaller than the first particle size d1 may contain a small amount of limestone crushed sand with a particle size exceeding the first particle size d1. The same is true for the limestone crushed sand CS2 that is larger than the first particle size d1.

[0031] [First air separator 40: Classification at second particle size d2 (75 μm)] The first air separator 40 classifies the limestone crushed sand CS1 classified by the vibrating sieve 30 into the first particle size d1 or less at the second particle size d2, and separates it into limestone crushed sand CS3 having a size exceeding the second particle size d2 and lime powder PW1 having a size equal to or less than the second particle size d2. This process corresponds to the third process of the present invention. The lime powder PW1 corresponds to the third classified product of the present invention. The first air separator 40 performs dry classification by utilizing centrifugal force and a circulating swirling air current. The first air separator 40 includes a casing 41, a crushed stone inlet 42, a small diameter outlet 43, and a large diameter outlet 44. The casing 41 is supplied with crushed limestone sand CS1 classified by the vibrating sieve 30 to a first particle size d1 or less from a crushed stone inlet 42. A fan blade (not shown) is disposed inside the casing 41, and the fan blade is rotated by a drive source connected to the fan blade, generating centrifugal force and a circulating swirling airflow inside the casing 41. The centrifugal force and circulating swirling airflow generated inside the casing 41 dry classify the crushed limestone sand CS1 supplied to the casing 41 at the boundary of the second particle size d2.

[0032] The relatively small-diameter limestone powder PW1 carried along with the centrifugal force and circulating swirling air current generated inside the casing 41 is discharged from a small-diameter outlet 43. The relatively large-diameter crushed limestone sand CS3 not carried along by the centrifugal force and circulating swirling air current generated inside the casing 41 is discharged from a large-diameter outlet 44. By adjusting the strength of the centrifugal force and circulating swirling air current generated inside the casing 41, it is possible to arbitrarily change the size of the second particle size d2 as a predetermined particle size.

[0033] Here, as an example, the first air separator 40 adjusts the centrifugal force and the strength of the circulating swirling air current generated inside the casing 41 so that the crushed limestone sand CS3 discharged from the large diameter outlet 44 has a particle size that will not pass through a metal mesh sieve with a nominal mesh size of 75 μm as specified in JIS Z 8801-1. In this case, the particle size of the lime powder PW1 discharged from the small diameter outlet 43 is a particle size that will pass through a metal mesh sieve with a nominal mesh size of 75 μm. The limestone crushed sand CS3 discharged from the large diameter outlet 44 has a standard particle size for limestone crushed sand, and is a particle size that does not pass through a metal mesh sieve with a nominal mesh size of 75 μm, so it corresponds to a fine particle content of 0% as specified in JIS A 5005. The limestone crushed sand CS3, which corresponds to a fine particle content of 0%, can be easily adjusted to the fine particle content of the limestone crushed sand desired by the user.

[0034] The lime powder PW1 discharged from the small diameter outlet 43 is supplied to the second air separator 50 via the fourth conveying path 14. The limestone crushed sand CS3 discharged from the large diameter outlet 44 is collected in the first collection area PA1 via the first collection path 15 and is commercialized as limestone crushed sand for concrete, for example.

[0035] In order to classify the limestone crushed sand CS into sizes exceeding the first particle size d1 (5 mm) and sizes equal to or smaller than the first particle size d1 (5 mm), a vibrating sieve is used instead of an air separator. This is because, in order to classify a large volume of limestone crushed sand CS at the first particle size d1 (5 mm), a vibrating sieve that classifies by sifting using vibrations is more efficient at classifying than an air separator, which is a so-called air-powered specific gravity separator.

[0036] [Second air separator 50: Classification at third particle size d3 (45 μm)] The second air separator 50 classifies the lime powder PW1 classified by the first air separator 40 into the second particle size d2 or less at the third particle size d3, and separates it into lime powder PW2 having a size of the third particle size d3 or less and lime powder PW3 having a size exceeding the third particle size d3. This step corresponds to the fourth step of the present invention. The lime powder PW3 corresponds to the fourth classified product of the present invention. The second air separator 50 performs dry classification using centrifugal force and a circulating swirling air current, similar to the first air separator 40. The second air separator 50 includes a casing 51, a crushed stone inlet 52, a small diameter outlet 53, and a large diameter outlet 54. The lime powder PW1 classified by the first air separator 40 into particles of the second particle size d2 or less is supplied to the casing 51 through the crushed stone inlet 52. A fan blade (not shown) is disposed inside the casing 51, and the fan blade is rotated by a drive source connected to the fan blade, generating centrifugal force and a circulating swirling airflow inside the casing 51. The lime powder PW1 supplied to the casing 51 is dry-classified at the third particle size d3 as a boundary by the centrifugal force and circulating swirling airflow generated inside the casing 51.

[0037] Relatively small-diameter lime powder PW2 carried along with the centrifugal force and circulating swirling airflow generated inside the casing 51 is discharged from a small-diameter outlet 53. Relatively large-diameter lime powder PW3 not carried by the centrifugal force and circulating swirling airflow generated inside the casing 51 is discharged from a large-diameter outlet 54. By adjusting the strength of the centrifugal force and circulating swirling airflow generated inside the casing 51, it is possible to arbitrarily change the size of the third particle size d3 as a predetermined particle size.

[0038] Here, as an example, the second air separator 50 adjusts the centrifugal force and the strength of the circulating swirling air current generated inside the casing 51 so that the particle size of the lime powder PW3 discharged from the large diameter outlet 54 is a particle size that will not pass through a metal mesh sieve with a nominal mesh size of 45 μm as specified in JIS Z 8801-1. In this case, the particle size of the lime powder PW2 discharged from the small diameter outlet 53 is a particle size that will pass through a metal mesh sieve with a nominal mesh size of 45 μm. The lime powder PW2 discharged from the small diameter outlet 53 has a particle size that passes through a metal mesh sieve with a nominal mesh size of 45 μm, and is an appropriate particle size for calcium carbonate powder for desulfurization. Therefore, the lime powder PW2 discharged from the small diameter outlet 53 is recovered in the second recovery area PA2 via the second recovery path 16 and is commercialized as calcium carbonate powder for desulfurization, for example. In addition, the lime powder PW3 that does not pass through the metal mesh sieve with a nominal mesh size of 45 μm has a particle size larger than the particle size of the calcium carbonate powder for desulfurization, so it is transported via the second return path 18 to the first conveying path 11 connected to the crushed stone inlet 22 of the double roll crusher 20, and is fed back into the double roll crusher 20 for crushing.

[0039] [Production method using production equipment 1: see Figure 2] The method for producing crushed limestone sand for concrete and calcium carbonate powder for desulfurization by the production apparatus 1 according to the embodiment includes a first step, a second step, a third step, and a fourth step as described below. First process: The supplied raw material crushed stone RM is crushed to produce limestone crushed sand CS. As an example of the crusher used in the first process, a double roll crusher 20 is applied. Second step: The limestone crushed sand CS from the first step is classified into limestone crushed sand CS1 having a size equal to or smaller than the first particle size d1 and limestone crushed sand CS2 having a size larger than the first particle size d1. The classification in the second step is performed, for example, by a vibrating sieve 30. For example, the first particle size d1 is set to 5 mm. Third step: The limestone crushed sand CS1 from the second step is classified into limestone crushed sand CS3 having a size exceeding the second particle size d2 and lime powder PW1 having a size equal to or smaller than the second particle size d2. The classification in the third step is performed, for example, by an air separator. The second particle size d2 is, for example, 75 μm. Fourth step: The lime powder PW1 from the third step is classified into lime powder PW2 having a size equal to or smaller than the third particle size d3 and lime powder PW3 having a size greater than the third particle size d3. The classification in the fourth step is performed, for example, by an air separator. The third particle size d3 is, for example, 45 μm.

[0040] In the production method according to the embodiment, the limestone crushed sand CS3 classified in the third step and the lime powder PW2 classified in the fourth step are manufactured into products as follows. Limestone crushed sand CS3: Limestone crushed sand for concrete (grain size distribution: 75-5000μm) Lime powder PW2: Calcium carbonate powder for desulfurization (particle size distribution: ≦45 μm)

[0041] In the production method according to the embodiment, the following classified products from the second and fourth steps are subjected to crushing in the first step together with the raw crushed stone RM. However, since the lime powder PW3 already has a small particle size, even if it is fed into the double roll crusher 20, some of the powder may simply pass through the double roll crusher 20 without being crushed. 1st particle size d1 < limestone crushed sand CS2 (2nd process) 3rd particle size d3 < lime powder PW3 (4th step) ≦ 2nd particle size d2

[0042] [effect] The production device 1 according to the present embodiment described above provides the following advantages. [First effect] The production device 1 is equipped with a vibrating sieve 30 for classifying the limestone crushed sand CS into limestone crushed sand CS1 having a size of a first particle size d1 or less and limestone crushed sand CS2 having a size exceeding the first particle size d1, a first air separator 40 as a classifier for classifying the limestone classified into limestone powder PW1 having a size of a second particle size d2 or less and limestone crushed sand CS3 having a size exceeding the second particle size d2, and a second air separator 50 as a classifier for classifying into limestone powder PW2 having a size of a third particle size d3 or less and limestone powder PW3 having a size exceeding the third particle size d3, thereby enabling stepwise classification. Here, the limestone crushed sand CS3 for concrete having a size of a first particle size d1 or less and a size exceeding the second particle size d2, and the limestone powder PW2 having a size of a third particle size d3 or less is calcium carbonate powder for desulfurization. As a result, the production equipment 1 forming a single manufacturing line can produce limestone crushed sand CS3, and also produce limestone powder PW2, which becomes calcium carbonate powder for desulfurization, by utilizing the limestone powder PW1 generated during the production of the limestone crushed sand CS3. Furthermore, according to the production apparatus 1, the crushed limestone sand CS3 does not contain any lime powder having a size of 75 μm or less, or if it does contain any, the amount is small. This makes it possible to remove limestone fines that are equal to or smaller than the second particle size d2 and larger than the third particle size d3 from the lime powder PW1. Since the recovered crushed limestone sand CS3 does not contain fines, it is possible to easily adjust the amount of fines to a desired amount by adding a predetermined amount of fines to the recovered crushed limestone sand CS3.

[0043] [Second effect] The production device 1 mixes the crushed limestone sand CS2, which has a particle size large enough for concrete use, and the lime powder PW3, which has a particle size large enough for calcium carbonate powder for desulfurization, with the raw crushed stone RM and supplies the resulting mixture to the double roll crusher 20. This makes it possible to consume all of the raw material crushed stone RM supplied to the production device 1 in the production of limestone crushed sand CS3 and lime powder PW2 without leaving any waste.

[0044] [Third effect] The production device 1 uses a double roll crusher 20 to crush the raw crushed stone RM and the limestone crushed sand CS2 and lime powder PW3 to be mixed with the raw crushed stone RM. Due to its crushing mechanism, the double roll crusher 20 can continue to crush stably even when crushing objects having such a wide range of particle sizes. Therefore, the production device 1 can produce limestone crushed sand for concrete and calcium carbonate powder for desulfurization with high production efficiency. Moreover, the double roll crusher 20 is capable of adjusting the distance between the two crushing rolls (the first roll 23 and the second roll 24). This makes it possible to adjust the size distribution of the crushed sand crushed by the double roll crusher 20.

[0045] [Fourth effect] The production device 1 supplies limestone classified to a size exceeding a first particle size d1 to the double roll crusher 20, and supplies limestone classified to a size exceeding a third particle size d3 to the double roll crusher 20. This makes it possible to produce limestone crushed sand CS3 for concrete and calcium carbonate powder for desulfurization using all of the raw crushed stone RM supplied to the production equipment 1 without waste, with no or only trace amounts of limestone powder of 75 μm or less.

[0046] <Second embodiment: see Figs. 3 and 4> The production apparatus 1 according to the first embodiment includes a first air separator 40 and a second air separator 50 in addition to the vibrating sieve 30, but the present invention is not limited thereto. As shown in Fig. 3, the production apparatus 2 according to the second embodiment can omit the first air separator 40 and classify the limestone crushed sand CS1 classified by the vibrating sieve 30 by the second air separator 50. In Figs. 3 and 4, the same elements as those in the first embodiment are denoted by the same reference numerals as those in Figs. 1 and 2, and the description thereof will be omitted.

[0047] According to the production device 2, as shown in Fig. 4, the limestone crushed sand CS1 is classified at the third particle size d3 (45μm) as a boundary, and is divided into limestone crushed sand CS4 having a size exceeding the third particle size d3 and lime powder PW4 having a size equal to or smaller than the third particle size d3. The limestone crushed sand CS4 is used as limestone crushed sand for concrete, and the lime powder PW4 is used as calcium carbonate powder for desulfurization. Therefore, the limestone crushed sand CS4 corresponds to the limestone crushed sand CS3 in the first embodiment, and the lime powder PW4 corresponds to the lime powder PW2 in the first form.

[0048] The crushed limestone sand CS4 and the lime powder PW4 are compared with the crushed limestone sand CS3 and the lime powder PW2 of the first embodiment. The particle sizes of these are listed below. The lime powder PW4 has the same particle size range as the lime powder PW2, but the crushed limestone sand CS4 contains lime powder with a particle size of 75 μm or less, which is smaller than that of the crushed limestone sand CS3. Therefore, although the production device 2 cannot reduce the fine particle content to 0%, it is sufficient to install one air separator, which makes it possible to keep production costs low. Limestone crushed sand CS4: 45~5000μm Limestone crushed sand CS3:75~5000μm Lime powder PW4:≦45μm Lime powder PW2:≦45μm

[0049] In addition to the above, the configurations given in the above embodiments can be selected or appropriately changed to other configurations without departing from the spirit of the present invention.

[0050] The production apparatuses 1 and 2 use a double roll crusher 20 as a crusher, but the crusher of the present invention is not limited to this. In other words, as long as it can crush the raw crushed stone RM and can process powder with a small particle size such as the lime powder PW3, it corresponds to the crusher of the present invention. For example, a crusher equipped with only one crushing roll and other crushers can be applied to the present invention. The production apparatus of the present invention can be applied to the simultaneous production of crushed limestone sand for concrete and calcium carbonate powder for desulfurization, as well as the production of a number of granular materials with different particle size ranges. [Explanation of symbols]

[0051] 1 Production equipment 2. Production Equipment 10 Raw material hopper 11 First conveyor path 12 Second conveyor path 13 Third Transport Path 14 4th Transport Route 15 First Recovery Route 16 Second Recovery Route 17 First Return Route 18 Second Return Route 20 Double Roll Crusher 21 Casing 22 Crushed stone inlet 23 Roll 1 24 Roll 2 25 Hydraulic Cylinder 25A Rod 26 Support member 26A Upper end side 26B Rotating support end 30 Vibrating sieve 31 Casing 32 Crushed stone inlet 33 Mesh 34 1st outlet 35 2nd outlet 40 First Air Separator 41 Casing 42 Crushed stone inlet 43 Small diameter exit 44 Large diameter exit 50 Second Air Separator 51 Casing 52 Crushed stone inlet 53 Small diameter exit 54 Large diameter exit CS crushed limestone sand CS1,CS2,CS3,CS4 Limestone crushed sand d1 1st particle size d2 2nd particle size d3 3rd particle size H horizontal direction V vertical direction PA1 First Recovery Area PA2 Second Recovery Area PW1,PW2,PW3,PW4 Lime powder RM Raw Crushed Stone

Claims

1. A crusher for crushing the raw material crushed stone supplied; At least two classifiers for sequentially classifying the crushed material crushed by the crusher; The classifier comprises: A first classifier that classifies the crushed product into a size exceeding a first particle size d1 and a size equal to or smaller than the first particle size d1; A production apparatus comprising: a second classifier that classifies the first classified product classified by the first classifier to a size equal to or less than the first particle size d1 into a size exceeding a third particle size d3 and a size equal to or less than the third particle size d3.

2. The crusher comprises at least one roll, The first classifier is a vibrating sieve, The second classifier is a second air separator that performs dry classification. The production device according to claim 1 .

3. A first return path is provided for transporting the second classified material classified into a size exceeding the first particle size d1 from the first classifier to the crusher. The production apparatus according to claim 1 or 2.

4. The crusher is a double roll crusher having two driven rolls, The two rolls are adjacent to each other, and the distance between the two rolls is adjustable. The production apparatus according to claim 2.

5. The first classifier is a vibrating sieve, The second classifier includes the second air separator and a first air separator provided upstream of the second air separator, The first air separator dry-classifies the first classified product classified by the vibrating sieve into a size equal to or less than the first particle size d1 into a size exceeding a second particle size d2 and a size equal to or less than the second particle size d2, The second air separator dry-classifies the third classified product classified by the first air separator into a size equal to or less than the second particle diameter d2 into a size exceeding the third particle diameter d3 and a size equal to or less than the third particle diameter d3. The production apparatus according to claim 2 or 4.

6. A first return path for conveying the second classified material classified into a size exceeding the first particle size d1 from the vibrating sieve to the crusher; A second return path for transporting a fourth classified material classified to a size exceeding the third particle size d3 from the second air separator to the crusher. The production apparatus according to claim 5.

7. A first step of crushing the supplied limestone; A second step of classifying the limestone crushed in the first step into a size exceeding a first particle size d1 and a size equal to or smaller than the first particle size d1; A fourth step of classifying the crushed limestone sand classified into the first particle size d1 or less by the second step into a size exceeding a third particle size d3 and a size equal to or less than the third particle size d3, The crushed limestone sand having a size equal to or less than the first particle size d1 and exceeding the third particle size d3 is used for concrete, The lime powder having a size equal to or less than the third particle size d3 is used for desulfurization. Production method.

8. The crushed limestone sand classified to a size exceeding the first particle size d1 is transported to the first step; 8. The method of claim 7.

9. The size exceeding the first particle size d1 is a size that does not pass through a sieve with a nominal size of 5 mm, The size of the first particle size d1 or less is a size that passes through a sieve with a nominal size of 5 mm, The size exceeding the third particle size d3 is a size that does not pass through a metal mesh sieve having a nominal opening of 45 μm, The size of the third particle size d3 or less is a size that passes through a metal mesh sieve with a nominal opening of 45 μm. The method of claim 7 or claim 8.

10. A third step of dry classifying the crushed limestone sand classified into the first particle size d1 or less by the second step into a size exceeding the second particle size d2 and a size less than the second particle size d2; The fourth step is to dry classify the lime powder classified into the second particle size d2 or less by the third step into a size exceeding the third particle size d3 and a size less than the third particle size d3.

8. The method of claim 7.

11. The crushed limestone sand classified to a size exceeding the first particle size d1 is transported to the first step; The lime powder classified to a size exceeding the third particle size d3 is transported to the first step.

11. The method of claim 10.

12. The size exceeding the first particle size d1 is a size that does not pass through a sieve with a nominal size of 5 mm, The size of the first particle size d1 or less is a size that passes through a sieve with a nominal size of 5 mm, The size exceeding the third particle size d3 is a size that does not pass through a metal mesh sieve having a nominal opening of 45 μm, The size of the third particle size d3 or less is a size that passes through a metal mesh sieve having a nominal opening of 45 μm, The size exceeding the second particle size d2 is a size that does not pass through a metal mesh sieve with a nominal mesh size of 75 μm, The size of the second particle size d2 or less is a size that passes through a metal mesh sieve with a nominal mesh size of 75 μm.

11. The method of claim 10.

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