Wet-particle fluidization blast method

Abstract

To provide a wet-particle fluidization blast method using a grinding material that is manufactured in a wet state without being dried.SOLUTION: A manufacturing method for a grinding material comprises a step of preparing coal ashes, a step of supplying water to the coal ashes and stirring the ashes, a step of classifying the coal ashes supplied with water and stirred, a step of packing the classified coal ashes, a step of supplying water to the packed coal ashes and pressing the ashes to subject the coal ashes to wet particle fluidization, and a step of jetting the coal ashes subjected to wet particle fluidization to a surface of a work-piece.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a wet particle slaking blasting method.

Background Art

[0002] Conventionally, for a painted surface applied to a steel structure such as a bridge, a blasting method is known in which an abrasive containing sand is sprayed by compressed air to remove rust and an old paint film and to clean the surface of the steel material.

[0003] The blasting method is generally classified into air blasting, vacuum blasting, and wet blasting. Among these, wet blasting is a method in which water and an abrasive are mixed and blasted, and in recent years, it has been increasingly used because of the advantage of less generation of dust.

[0004] For example, Patent Document 1 discloses a blasting material for wet blasting in which 5 to 30% by mass of moisture is contained in alumina, garnet, silica sand, glass beads, silicon carbide, or slag as an abrasive, and all abrasive particles are pre-adjusted to be wetted.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As abrasive materials, ferronickel slag, fused alumina, almandite garnet, copper slag, and steel grit are known. However, these conventional blasting materials are mixed with water immediately before the blasting process, and the abrasive materials themselves were not manufactured in a wet state. That is, since the conventional abrasive materials were subjected to a dryer during the manufacturing process, there were problems such as the need for time-consuming drying and the generation of dust.

[0007] Therefore, an object of the present invention is to provide a wet particle slurring blasting method using an abrasive material manufactured in a wet state without drying.

Means for Solving the Problems

[0008] To achieve the above object, the wet particle slurring blasting method of the present invention includes a step of preparing fly ash, a step of adding water to the fly ash and stirring, a step of classifying the fly ash added with water and stirred, a step of bagging the classified fly ash, a step of supplying water to the bagged fly ash and pressurizing to form wet particles into a slurry, and a step of spraying the wet particle slurried fly ash onto the surface of the workpiece.

Effects of the Invention

[0009] Thus, the wet particle slurring blasting method of the present invention includes a step of preparing fly ash, a step of adding water to the fly ash and stirring, a step of classifying the fly ash added with water and stirred, a step of bagging the classified fly ash, a step of supplying water to the bagged fly ash and pressurizing to form wet particles into a slurry, and a step of spraying the wet particle slurried fly ash onto the surface of the workpiece. With such steps, it is possible to manufacture and use the abrasive material in a wet state without drying the fly ash as the raw material.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the components described in the following examples are illustrative, and are not intended to limit the technical scope of the present invention thereto.

[0012] (Manufacturing System of Abrasive Material) First, the overall configuration of the abrasive material manufacturing system S will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the abrasive material manufacturing system S mainly includes a dissolving tank 10 that receives coal ash as a raw material and is supplied with water and agitated, a wet two-stage vibrating sieve 11 for classifying the pumped coal ash, a lower water tank 12 that receives the fine particles and water that have passed through the vibrating sieve 11, and a dehydration tank 13 that houses a dehydration bag 13a that receives the fine particles and water pumped from the lower water tank 12.

[0013] The dissolving tank 10 is, for example, a cylindrical container, and coal ash (clinker ash or IGCC slag) as a material before classification and water are charged and stored (steps S1, S2). Further, by rotating the stirring blade 10a by a motor 21 installed on the dissolving tank 10, the coal ash and water are kneaded (step S3). Here, the ratio of the material before classification and water in the dissolving tank 10 can be, for example, about 1:3.

[0014] In the dissolution tank 10, by circulating the overflow water from the dehydration layer 13 described later, a certain amount of water is maintained. Note that the size (diameter and height) of the dissolution tank 10 is preferably set according to the processing capacity. Specifically, it is necessary to maintain the water surface so that it does not become lower than the stirring blade 10a so that the pre-classification material and water can be easily kneaded.

[0015] Here, as the coal ash prepared in this embodiment, it is preferable to use clinker ash (CA) or IGCC slag. Clinker ash (CA) is the ash obtained by collecting the lumps of coal ash that have fallen to the bottom of the boiler among the coal ash generated when coal is burned, and dehydrating and pulverizing the ash. IGCC slag (coal gasification slag) is a glassy slag generated as a by-product in integrated gasification combined cycle (IGCC).

[0016] The dissolution tank 10 and the wet vibrating sieve 11 are connected by a pipe, and a slurry-like kneaded material of the pre-classification material and water is pumped from the dissolution tank 10 to the vibrating sieve 11 by a pump 22 (step S4).

[0017] The vibrating sieve 11 as a wet classifier is a two-stage type composed of an upper sieve 11a and a lower sieve 11b. By vibrating the upper sieve 11a and the lower sieve 11b with a motor (not shown), the kneaded material of wet coal ash and water can be sorted according to the particle size. In this embodiment, a sieve (sieve) with a first particle size of 2.0 mm is used as the upper sieve 11a with a coarse mesh, and a sieve (sieve) with a second particle size of 0.3 mm is used as the lower sieve 11b with a fine mesh. Note that if the vibrating sieve 11 selects appropriate specifications such as the shape and inclination of the vibrating surface, the water drainage in the next process can also be omitted.

[0018] Therefore, on the upper sieve 11a with a coarse mesh, a kneaded material of coal ash and water with a particle size of 2.0 mm or more (material of 2.0 mm or more) remains (step S5), and the kneaded material of fine coal ash and water with a particle size of less than 2.0 mm that has passed through the upper sieve 11a is further sieved by the lower sieve 11b in the lower stage (step S6).

[0019] And since the materials with a thickness of 2.0 mm or more remaining on the upper screen 11a are not suitable as abrasive materials and are not used, they are collected after being stored in a flexible container bag (step S11).

[0020] On the other hand, on the fine lower screen 11b, there remains a mixture of fly ash and water with a particle size of less than 2.0 mm and 0.3 mm or more (0.3 mm to 1.9 mm materials) (step S6). The finer mixture of fly ash (fine particles) and water with a particle size of less than 0.3 mm that has passed through the lower screen 11b is received in the lower water tank 12 (step S7).

[0021] That is, the 0.3 mm to 1.9 mm materials are bagged while in a wet state and used as abrasive materials. As will be described later, the mixture of fly ash and water bagged while in a wet state is preferably used in wet particle slurring blasting while in a wet state (step S12).

[0022] The lower water tank 12 and the dehydration tank 13 are connected by a pipe, and the materials with a particle size of less than 0.3 mm are pumped from the lower water tank 12 to the dehydration tank 13 by a pump 23 (step S8). Thereafter, the materials with a particle size of less than 0.3 mm are put into a dehydration bag 13a arranged in the dehydration layer 13 and dehydrated.

[0023] And the water that has come out of the dehydration bag 13a in the dehydration layer 13 is pumped back to the dissolution tank 10 by a pump 24. In this way, the overflow water of the dehydration tank 13 is circulated and reused.

[0024] (Wet particle slurring blasting) Next, with reference to FIG. 3, the configuration of the wet particle slurring blasting apparatus T will be described. The wet particle slurring blasting apparatus T mainly includes a water tank 31 for storing water, a built-in pump 32 that sucks water from the water tank 31 and pumps it to a pressurized tank 33, a pressurized tank 33 to which water from the water tank 31 and abrasive materials are supplied, an external compressor 34 for injecting abrasive materials wrapped in water (wet particle slurring abrasive materials), and a nozzle 35 for injecting the wet particle slurring abrasive materials onto the surface of the workpiece in a cyclone shape.

[0025] By using the wet-granulated slurry blasting device T in this way, the abrasive can be wet-granulated by pressurizing the inside of the pressure tank 33. That is, the abrasive is wrapped in water and becomes a wet-granulated state. And when this wet-granulated abrasive is discharged from the nozzle 35 and collides with the steel surface, the water film that wrapped the abrasive can grind and sweep while enclosing the paint together.

[0026] In particular, according to the method for manufacturing the abrasive of the above-described embodiment, since the abrasive is manufactured in a wet state, the abrasive and moisture have been familiarized in advance, and it is easier to maintain the wet-granulated state. That is, when the abrasive is introduced into the pressure tank 33, since the abrasive already holds moisture, the moisture and the abrasive are efficiently kneaded in the pressure tank 33 and are easily wet-granulated. In addition, since the abrasive is already in a wet state holding moisture, the amount of water supplied to the pressure tank 33 can be reduced.

[0027] The wet-granulated slurry blasting method using this wet-granulated slurry blasting device T has the following technical features and effects. 1) By specifying the material type, particle size, and Mohs hardness of the non-metallic abrasive, the quality of one type of specification can be ensured. 2) By selecting the mixing ratio of water and the abrasive, visibility is ensured by suppressing dust and preventing the scattering of harmful substances, etc., and the safety of the work is improved. Furthermore, the removal of surface deposits containing salts can be carried out simultaneously with the substrate adjustment. 3) By adopting a vaporized water-soluble rust inhibitor, re-rusting can be prevented.

[0028] In this way, by using this wet particle sludging blasting device T, abrasive materials covered with a water film can wrap paint, rust, and harmful substances when colliding with the surface of steel or the like, thereby suppressing dust and preventing scattering. At the same time, it is possible to remove adhering salts that are difficult to remove by the conventional dry blasting method, and the treatment in one step becomes possible. Furthermore, as a substrate conditioning method aiming at using high-quality single-kind keren, it is also possible to surely wet and remove lead-containing paint films, which have been a problem in recent years.

[0029] More specifically, the wet particle sludging blasting method using the wet particle sludging blasting device T also has the following effects.

[0030] · Dust generation can be suppressed with compact mechanical equipment In the conventional dry blasting method, since the scattering and crushing dust of non-metallic abrasive materials are intense, large-scale equipment such as dust collection devices, dust protection temporary facilities, ventilation and air exchange facilities, and lighting devices are required during operation. In contrast, the blasting method of wet particle sludged abrasive materials can suppress dust generation with compact mechanical equipment and is excellent in terms of cost and hygiene.

[0031] · Corrosion prevention primer treatment is applicable Since a vaporized water-soluble rust inhibitor is applied, it is possible to ensure the quality up to the corrosion prevention primer treatment of the grinding surface. The application of the vaporized water-soluble rust inhibitor suppresses the generation of return rust and protects the steel surface up to the corrosion prevention primer treatment, so the quality within 4 hours determined in the steel road bridge corrosion prevention manual can be ensured.

Example

[0032] Next, with reference to FIGS. 4 to 6, an applicability confirmation test conducted to confirm the particle size of the abrasive material suitable for the wet particle soil type blasting equipment will be described. In this applicability confirmation test, for clinker ash and IGCC slag, abrasive materials with two types of particle sizes are created respectively. Then, the effects are confirmed in the blasting test using the created abrasive materials. The particle sizes of the abrasive materials are the following two types.

[0033] · Clinker ash: 1) 0.3 mm to 1.9 mm, 2) 1.9 mm or less ·IGCC slag: 1) 0.3 mm to 1.9 mm, 2) 1.9 mm or less

[0034] In the production of abrasive materials, an efficient classification system is selected, and the classification effect and quality are confirmed through indoor tests before and after classification. As described below, a wet classification system is selected as the manufacturing method of abrasive materials suitable for the wet particle slaking type blasting equipment.

[0035] (1) Abrasive material processing The clinker ash and IGCC slag generated in the power plant were processed into wet abrasive materials. In this abrasive material compatibility confirmation test by blasting, since both the clinker ash and IGCC slag are carried out in two cases of abrasive material particle sizes of 0.3 mm to 1.9 mm and 1.9 mm or less, a two-stage vibrating screen 11 was selected for the production of abrasive materials of 0.3 mm to 1.9 mm (first-stage classification), and screens with an upper stage of 2.0 mm and a lower stage of 0.3 mm were installed. For the production of abrasive materials of 1.9 mm or less in the second-stage classification, it was planned to use a kneader to mix and stir a predetermined amount of materials less than 0 to 0.3 mm generated in the first-stage classification with the first-stage classification materials to produce abrasive materials.

[0036] (2-1) First-stage classification (2-2) Classification flow Using Fig. 1 and Fig. 2, the equipment and processes as described above are used.

[0037] (Discussion) Due to the selected compact and simple wet vibrating screen 11 for the trial system, water drainage and dehydration were insufficient during the screen movement of the materials. When directly packed in plastic bags, it became overly wet, so it was packed in sandbags, and after dehydration for a predetermined time, the outside was sealed with a plastic bag.

[0038] If the proper specifications such as the shape and inclination of the vibrating surface of the vibrating screen 11 are selected, water drainage in the next process can be omitted, and bagging efficiency can be improved.

[0039] The ratio of the material to water in the dissolution tank 10 was set at 1:3. Although it was planned to circulate the overflow water, tap water was used in the first half because there was little overflow water. During the process, the material separated due to the insufficient water volume in the dissolution tank 10, resulting in clogging. In the second half, by circulating the overflow water, sufficient kneading was achieved and the material could be smoothly pumped.

[0040] The relatively large shape and dimensions of the dissolution tank 10 were also a factor in material separation during a small amount of dissolution (kneading of water and material). Also, it is necessary to constantly add an appropriate amount of water according to the state so that the water surface does not drop below the stirring blade 10a. Therefore, it is necessary to select a dissolution tank 10 with an appropriate shape, size, and specifications.

[0041] The under material is pumped together with the surplus water to the dehydration tank 13 at 5m 3 and dehydrated by the dehydration filter 13a. At this time, fine-grained norovirus flows out from the surplus water through the dehydration filter 13a. Therefore, in the initial stage of surplus water storage, the turbidity is high. However, the norovirus of clinker ash and IGCC slag settles quickly in water, and the supernatant water becomes about SS200 or less the next day, enabling drainage that complies with the sewer drainage standard (less than SS600). In order to reduce the drainage volume, the recycling of surplus water is also important.

[0042] The time required to create the air bag by the wet vibrating sieve machine 11 this time was about 30 seconds to 1 minute and 30 seconds per bag, depending on the adjustment of the pumping volume according to the situation by the inverter pump.

[0043] (2-3) Classification results of the first process The particle size composition of the materials and the first process classified materials transported to the Dae Bong Construction Technology Research Institute was confirmed by a simple sieving test in the laboratory. Also, the unit volume weight and water content ratio were similarly confirmed by indoor tests.

[0044] As shown in Fig. 4(a), in terms of the particle size distribution, for the clinker ash before classification (incoming material), the oversize material of 2.0 mm or more accounted for 6.7%, while for the first classified material, it was 1.0%. Also, for the IGCC slag before classification (incoming material), the undersize material of 0.25 mm or less accounted for 21.4%, while for the first classified material, it was 1.3%. That is, for the clinker ash, the oversize material is mainly separated by the first-stage classification, and for the IGCC slag, the undersize material is mainly separated by the first-stage classification to adjust the particle size.

[0045] As shown in Fig. 4(b), in terms of the bulk density, as a result of measurement on the incoming material before classification, the bulk density of the clinker ash was 0.852 g / cm 3 and that of the IGCC slag was 1.853 g / cm 3 .

[0046] As shown in Fig. 4(c), in terms of the water content ratio, the water content ratio of the first classified material of the clinker ash was 35.6%. Also, the water content ratio of the first classified material of the IGCC slag was 2.2%.

[0047] (3-1) Second-stage classification The following classification was carried out on the first-stage classified material to produce abrasive materials.

[0048] (3-2) Second-stage classification of clinker ash In order to remove the undersize material of less than 0 - 0.3 mm from the first-stage classified abrasive material, reclassification was carried out to produce abrasive materials of 0.3 - 1.9 mm.

[0049] · Equipment used Hand mixer, 18 L pale can, 0.3 mm sieve mesh (used with a wet vibrating sieve machine)

[0050] · Classification procedure 1) Divide the first-stage classified material into four parts (about 5 kg) and put it into a pale can. 2) Add water (abrasive material : water = 1:2) 3) Mix and stir with a hand mixer (for 1 minute) 4) Discharge onto a 0.3 mm sieve 5) Recover the classified material 6) Repeatedly pack the sandbags 4 times and dehydrate. 7) Repeat the above steps 1)-6) to create 3 bags (about 60 kg).

[0051] (3-3) Secondary classification of IGCC slag Mix the undersize material less than 0 - 0.3 mm into the ground material classified in the first step to produce ground material less than 1.9 mm.

[0052] · Mixing amount From the particle size test results before IGCC classification (Figure 4(a)), Less than 2 mm: 92.1%, less than 0.25 mm: 21.4% From the particle size test results after IGCC classification (Figure 4(a)), Less than 0.25 mm: 1.3% Therefore, the material less than 0.25 mm in 25 kg of the sample requires 25 kg × (21.4% / 92.1% - 1.3% / 100%) ≈ 6 kg

[0053] · Materials and equipment used Materials: The undersize IGCC slag material less than 0 - 0.3 mm that has settled in the lower water tank 12 of the wet vibrating sieve 11 Equipment: Kneader

[0054] · Mixing procedure 1) Prepare 19 kg of the ground material in the first step (0.3 mm - 1.9 mm) and 6 kg of the undersize material (less than 0 - 0.3 mm). 2) Manually knead the above materials simply, then put them into the kneader and mix and stir automatically. 3) Open the door at the bottom of the kneader, temporarily receive it in a container, and then pack it into sandbags. 4) Repeat the above steps 1)-3) to create 3 bags (about 75 kg).

[0055] (Discussion) · When producing IGCC slag into a grinding material of 1.9 mm or less by wet classification, if a two-stage vibrating sieve machine (11) such as the first-stage classification is used, it is impossible to retain the undersize material, and it passes through the sieve and stays in the lower water tank 12 together with the excess water. This time, the retained undersize material was added and kneaded, but since it was not efficient, for example, if there is an effect in classification by a 2.0 mm sieve in one stage after material grinding (in a wet state), it is considered efficient.

[0056] (3-4) Second-stage classification result Regarding the effect of reclassification of clinker ash, as a result of conducting a sieving test, as shown in Fig. 5, a high separation effect was confirmed for the dissolution method using a hand mixer for clinker ash. Regarding IGCC slag, since a predetermined amount was mixed in, the test was omitted.

[0057] (4) Confirmation of the particle size of the grinding material suitable for the wet granular soil blasting equipment For the confirmation of the particle size of the grinding material suitable for the wet granular soil blasting equipment, two cases were set: one with a particle size range similar to that of the finished product and the other including the undersize material. Using a 1 m × 1 m black-plated iron plate and the center materials (coating film) in the Daito Construction Technology Research Institute as test specimens, a blasting test construction was carried out using the classified grinding material.

[0058] (Discussion) All evaluations as blast grinding materials satisfy the quality of Sa1 1 / 2 of the coating removal standard. Regarding the construction efficiency, since clinker ash is porous and softer than IGCC slag in hardness, the construction time was long and the efficiency was low.

[0059] As shown in Fig. 6, regarding the results due to the difference in the particle size range, in both the case of clinker ash and IGCC slag, the case including the undersize material had a shorter construction time. The material consumption per construction area was almost the same. It is speculated that the reason for this is that since the pressure setting etc. were not changed, the fluidity improved by including the undersize material, and the blast injection amount per unit time increased.

[0060] (Effect) Next, the effects of the manufacturing method of the abrasive material according to the present embodiment will be listed and described. (1) As described above, the manufacturing method of the abrasive material of this example includes a step of preparing coal ash, a step of adding water to the coal ash and stirring it, a step of classifying the coal ash that has been added with water and stirred, a step of bagging the classified coal ash, a step of supplying water to the bagged coal ash, pressurizing it, and making it into wet granular mud, and a step of spraying the wet granular mud coal ash onto the surface of the workpiece. By providing such steps, it is possible to manufacture and use the abrasive material while keeping the raw material coal ash in a wet state without drying it. That is, without intervening a step of drying coal ash in the middle as in the prior art, it is possible to efficiently manufacture and use the wet granular abrasive material while maintaining the wet state. Furthermore, the wet granular abrasive material can suppress the generation of dust and remove the surface deposits of the workpiece containing salt. In addition, if a vaporized water-soluble rust preventive agent is used, it is also possible to prevent re-rusting.

[0061] (2) Among these, in the step of making wet granular mud, water is pumped into the pressure tank 33 by the built-in pump 32, so that water pressure is applied to the coal ash in the pressure tank 33. Therefore, the coal ash can be efficiently and evenly made into wet granular mud throughout.

[0062] (3) Also, in the step of bagging the coal ash, since the coal ash is bagged while in a wet state, it is possible to suppress the generation of dust in the manufacturing process, and it is also possible to suppress the generation of dust when using the coal ash adjusted as an abrasive material. Furthermore, by using the wet granular blasting device T, the compatibility with moisture can be improved and the amount of water used can be reduced.

[0063] (4) Furthermore, in the step of classifying the coal ash, by using a two-stage vibrating sieve 11 composed of an upper screen 11a and a lower screen 11b as a wet classifier, oversize materials coarser than a predetermined first particle size and undersize materials finer than a second particle size smaller than the first particle size are removed. Therefore, it is possible to efficiently and accurately perform particle size adjustment.

[0064] (5) Also, in the step of classifying the coal ash, it is also preferable to use a one-stage vibrating screen machine (11) composed only of an upper screen (11a) as a wet classifier so that oversize materials coarser than a predetermined first particle size are removed. By doing so, it is possible to perform the particle size adjustment more efficiently and with high accuracy.

[0065] (6) Also, as for the coal ash, by conducting a confirmation test using clinker ash and IGCC slag, it was confirmed that clinker ash or IGCC slag, which was not conventionally used as an abrasive, can be newly used as an abrasive.

[0066] Note that since other configurations and operational effects are substantially the same as those in the above-described embodiment, the description thereof is omitted.

[0067] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes that do not deviate from the gist of the present invention are included in the present invention.

[0068] For example, in the embodiment, the case of using clinker ash and IGCC slag as the coal ash that is the raw material of the abrasive was described. However, the present invention is not limited thereto, and other types of coal ash can also be applied to the wet particle slurring blasting method of this embodiment.

Explanation of Reference Numerals

[0069] S Manufacturing system of abrasive 10 Dissolution tank 10a Stirring blade 11 Vibrating screen machine 12 Lower water tank 13 Dewatering tank 13a Dewatering bag 21 Motor 22 - 25 Pumps T Wet particle slurring blasting device 31 Water tank 32 Built-in pump 33 Pressure tank 34 External compressor 35 nozzles

Claims

1. A step of preparing coal ash; A step of adding water to the coal ash and stirring; A step of classifying the coal ash that has been added with water and stirred; A step of bagging the classified coal ash; A step of supplying water to the bagged coal ash, pressurizing it, and wet granulating it; A step of spraying the wet granulated coal ash onto the surface of the workpiece; A wet granulation blasting method comprising the above.

2. The wet granulation step is such that water is pressure-fed into a pressure tank by a pump to apply water pressure to the coal ash in the pressure tank. The wet granulation blasting method according to Claim 1.

3. The step of bagging the coal ash is such that the coal ash is bagged while remaining in a wet state. The wet granulation blasting method according to Claim 2.

4. The step of classifying the coal ash is such that by using a wet classifier, oversize material coarser than a predetermined first particle size and undersize material finer than a second particle size smaller than the first particle size are removed. The wet granulation blasting method according to Claim 3.

5. The step of classifying the coal ash is such that by using a wet classifier, oversize material coarser than a predetermined first particle size is removed. The wet granulation blasting method according to Claim 3.

6. The coal ash is clinker ash or IGCC slag. The wet granulation blasting method according to any one of Claims 1 to 5.

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