Sand reclamation device and sand reclamation method

Abstract

The molding sand regenerating apparatus of the present disclosure is an apparatus for regenerating molding sand from a molding sand composition containing molding sand and a water-soluble binder, and is provided with a treatment apparatus, a liquid discharge apparatus, and a drying apparatus. The treatment apparatus includes a container into which the molding sand composition and an aqueous medium are charged, and a stirring apparatus that stirs and mixes the molding sand composition and the aqueous medium charged into the container. The liquid discharge apparatus discharges at least a part of the liquid component from the mixture of the molding sand composition and the aqueous medium present in the container after the stirring and mixing. The drying apparatus dries the residue containing the molding sand remaining in the container after the liquid discharge. The molding sand regenerating apparatus stirs the residue by the stirring apparatus while drying the residue by the drying apparatus.

Description

Technical Field

[0001] This disclosure relates to a molding sand regeneration apparatus and a molding sand regeneration method. Background Technology

[0002] This disclosure relates to a molding sand regeneration apparatus and a molding sand regeneration method.

[0003] As a casting method for producing castings (metal products), there is sand casting, which uses a sand composition containing molding sand (casting sand, granular refractory material) and binder (adhesive) as the mold material.

[0004] Traditionally, molding sand compositions have been recovered from casting molds, subjected to a regeneration process to remove binders, and then reused as recycled molding sand for casting.

[0005] Binders used in molding are broadly classified into organic binders such as phenolic resins and furan resins, and inorganic binders such as sodium silicate (water glass). Generally speaking, inorganic binders are preferred because they produce less odor and CO2 emissions during molding and disintegration, but they tend to be difficult to remove from the surface of the molding sand.

[0006] One method for regenerating molding sand is a wet method that includes the following cleaning steps: adding an aqueous medium (preferably water) to the molding sand composition recovered from the mold used for casting and stirring to dissolve the water-soluble inorganic binder adhering to the molding sand in the aqueous medium (e.g., claim 1 of Patent Document 1).

[0007] In this method, after the cleaning process is completed, a separation process is required to separate the wet molding sand from the aqueous medium containing water-soluble inorganic binder, and a drying process is required to dry the wet molding sand obtained after the separation process.

[0008] In Patent Document 1, the above-mentioned cleaning process is described in the document. Figure 1 The washing process is carried out in a sealable container with a stirring function, as shown. After this washing process, the contents of the container are removed and filtered to separate them into wet molding sand and an aqueous medium containing dissolved water-soluble inorganic binders (section 0030). Finally, a drying process is carried out to dry the wet molding sand (section 0031).

[0009] Patent Document 1: Japanese Patent Application Publication No. 2016-129897 Summary of the Invention

[0010] In the aforementioned conventional regeneration methods, the washing, separation, and drying processes are performed using different equipment. After the washing process, the contents removed from the container are wet sand containing an aqueous medium, resulting in poor processability. Therefore, operations such as removing the contents from the container and transferring them to the next process require time, effort, and cost.

[0011] This disclosure was made in view of the above circumstances, and its purpose is to provide a molding sand regeneration apparatus and method that can efficiently perform the cleaning, separation and drying processes.

[0012] The disclosed molding sand recycling apparatus is a device for recycling molding sand from a molding sand composition comprising molding sand and a water-soluble binder. It includes a container, a stirring device, a draining device, and a drying device. The molding sand composition and an aqueous medium are added to the container. The stirring device mixes the molding sand composition and the aqueous medium in the container. After mixing, the draining device discharges at least a portion of the liquid component from the mixture of the molding sand composition and the aqueous medium present in the container. The drying device includes a heating or temperature control device for heating or adjusting the temperature inside the container and / or a pressure reducing device for reducing the pressure inside the container. After draining, residues containing the molding sand remaining in the container are dried. The molding sand recycling apparatus simultaneously stirs the residues with the stirring device and dries the residues using the drying device.

[0013] The present disclosure discloses a molding sand regeneration method for regenerating molding sand from a molding sand composition comprising molding sand and a water-soluble binder. The method comprises: a step (S1) of adding the molding sand composition and an aqueous medium into a container; a step (S2) of stirring and mixing the molding sand composition and the aqueous medium in the container; a step (S3) of discharging at least a portion of the liquid component from the mixture of the molding sand composition and the aqueous medium present in the container after step (S2); and a step (S4) of drying the residue containing the molding sand remaining in the container while stirring after step (S3).

[0014] According to the molding sand regeneration apparatus and method disclosed herein, the cleaning process, separation process and drying process can be carried out efficiently in one container.

[0015] In the technology disclosed herein, after the cleaning process is completed, it is not necessary to remove the wet sand containing water-based media with poor treatment properties from the container, nor is it necessary to perform time-consuming, labor-intensive, and costly operations such as removing the wet sand from the container and conveying the wet sand to the next process.

[0016] According to the technology disclosed herein, the molding sand can be ground simultaneously with and / or after the drying process in the same container, as needed.

[0017] According to the technology disclosed herein, the obtained recycled molding sand can be cooled in the same container as needed.

[0018] According to the technology disclosed herein, all the processes required for regenerating molding sand from a molding sand composition containing molding sand and a water-soluble binder can be carried out efficiently in a single container.

[0019] According to this disclosure, a molding sand regeneration apparatus and a molding sand regeneration method are provided that can efficiently perform cleaning, separation and drying processes.

[0020] The above and other objects, features and advantages of this disclosure will be more fully understood from the following detailed description and accompanying drawings. Attached Figure Description

[0021] Figure 1 This is an overall structural diagram of a molding sand regeneration device according to one embodiment of the present invention.

[0022] Figure 2 This is a schematic side view of a processing apparatus according to one embodiment of the present invention.

[0023] Figure 3 This is a schematic cross-sectional view illustrating the separation of solid and liquid phases.

[0024] Figure 4 This is a flowchart of a molding sand regeneration method according to one embodiment of the present invention. Detailed Implementation

[0025] [Molding sand regeneration equipment and methods]

[0026] Referring to the accompanying drawings, a molding sand regeneration apparatus and a molding sand regeneration method according to one embodiment of the present invention will be described.

[0027] The molding sand recycling apparatus 1 of this embodiment is an apparatus for recycling molding sand from a molding sand composition containing one or more molding sands and one or more water-soluble binders.

[0028] The molding sand composition can be unmolded material before molding, unused material recovered from never-used molds, used material recovered from used molds, or a combination thereof.

[0029] Molding sand is a well-known granular refractory material, including general sands such as silica sand; mountain sand; special sands such as alumina sand, olivine sand, zircon sand and chromium sand; synthetic sands such as mullite sand; slag sand, etc.

[0030] As a water-soluble binder, water-soluble inorganic binders are preferred due to their low odor and CO2 emissions during molding and disintegration. Water-soluble inorganic binders can be well-known substances, including sodium silicate (water glass), potassium silicate, sodium metasilicate, potassium metasilicate, lithium silicate, ammonium silicate, colloidal silica, and alkyl silicate esters, among other silicate compounds.

[0031] The molding sand composition may also contain one or more additives other than molding sand and water-soluble binders.

[0032] The amount of water-soluble binder in the molding sand composition (in various cases, total amount) is not particularly limited, and can be more than 1% by mass and less than 10% by mass relative to 100% by mass of molding sand (in various cases, total amount). The lower limit is more preferably 2% by mass, particularly preferably 3% by mass. The upper limit is more preferably 8% by mass, particularly preferably 7% by mass, and most preferably 5% by mass.

[0033] like Figure 1 and Figure 2 As shown, the molding sand recycling device 1 includes a processing device 2, which includes a container 10 for feeding in the molding sand composition and an aqueous medium, and a stirring device 20 for mixing the molding sand composition and the aqueous medium fed into the container 10.

[0034] In the molding sand recycling device 1, the first step is to put the molding sand composition and the aqueous medium into the container 10 (step (S1)).

[0035] The container 10 is made of metal materials such as stainless steel, and includes a bottomed cylindrical (preferably bottomed cylindrical) container body 11 with an opening at the top and an openable and closable top cover 12, preferably a sealable container. In the figure, symbol 13 indicates a top cover support member.

[0036] The stirring device 20 may include a plurality of stirring blades 21 rotatably mounted near the inner bottom surface of the container body 11.

[0037] The processing device 2 may include a drive unit 30 for driving the stirring device 20. The drive unit 30 may include a motor (drive source) 31, a power transmission mechanism 32, and a shaft 33.

[0038] The processing device 2 includes a base portion 50 that houses the power transmission mechanism 32 of the drive unit 30 and a portion of the shaft 33, and a container 10 can be disposed on its upper surface 50S.

[0039] The molding sand recycling device 1 may include, as needed, a molding sand composition supply device such as a hopper for supplying the molding sand composition into the container 10 (illustration omitted).

[0040] The molding sand recycling device 1 may include, as needed, an aqueous medium supply device 60 for supplying aqueous medium into the container 10.

[0041] The aqueous medium supply device 60 may include a supply pipe 61 for supplying the aqueous medium into the container 10. The supply pipe 61 is connected to the container 10, preferably to the top cover 12 of the container 10. Preferably, a portion of the supply pipe 61 is inserted into the container 10.

[0042] The aqueous medium supply device 60 may further include a heating or temperature control device 62 for heating or temperature control of the aqueous medium supplied to and / or flowing in the supply pipe 61.

[0043] The aqueous medium supply device 60 may also include one or more other elements such as valves, flow meters, and pumps as needed.

[0044] Examples of aqueous media include water, alcohols, and combinations thereof; water is preferred from both cost and environmental perspectives. The aqueous media may contain one or more additives as needed. The water content in the aqueous media is preferably 90% by mass or more and 100% by mass or less. A lower limit of 95% by mass is more preferred, and particularly preferred is 98% by mass.

[0045] Unless otherwise specified, the preferred temperature conditions described below are those when the water content in the aqueous medium is 90% by mass or more.

[0046] From the viewpoint of improving the efficiency of removing water-soluble binders from molding sand, the temperature of the aqueous medium supplied to the container 10 is preferably 40°C or higher and 100°C or lower. The lower limit is more preferably 50°C, further preferably 60°C, even more preferably 70°C, particularly preferably 80°C, and most preferably 90°C. The upper limit is more preferably 99°C, further preferably 98°C, particularly preferably 97°C, and most preferably 95°C.

[0047] There is no particular limitation on the amount of aqueous medium added to container 10. From the viewpoint of improving the efficiency of removing water-soluble binders from molding sand, it is preferably 0.3L or more and 1.0L or less per 1kg of molding sand composition. The lower limit is more preferably 0.4L, and particularly preferably 0.5L. The upper limit is more preferably 0.9L, and particularly preferably 0.8L.

[0048] There is no particular limitation on the total volume of the molding sand composition and the aqueous medium added into container 10, but it is preferably 20% or more and 90% or less relative to 100% of the volume of container 10. The lower limit is more preferably 30%, particularly preferably 40%, and most preferably 50%. The upper limit is more preferably 80%, and particularly preferably 70%.

[0049] In the molding sand recycling device 1, the molding sand composition and the aqueous medium fed into the container 10 are stirred and mixed using a stirring device 20. Through this operation, a cleaning process (process (S2)) can be performed to dissolve the water-soluble adhesive adhering to the molding sand in the aqueous medium and remove the water-soluble adhesive from the molding sand.

[0050] In this method, unlike methods that physically remove water-soluble binders adhering to molding sand through impact and friction, even relatively weak forces can remove water-soluble binders from molding sand, thus reducing damage to the molding sand.

[0051] From the viewpoint of improving the removal efficiency of water-soluble adhesives, it is preferable to perform the cleaning process (process (S2)) while heating or adjusting the temperature of the container 10 using a heating or temperature control device 81. The cleaning process (process (S2)) can be performed under normal pressure or under pressure.

[0052] The temperature inside container 10 during the cleaning process (process (S2)) is not particularly limited, but if it is under normal pressure, it is preferably 40°C or higher and 100°C or lower. The lower limit is more preferably 50°C, further preferably 60°C, even more preferably 70°C, particularly preferably 80°C, and most preferably 90°C. The upper limit is more preferably 99°C, further preferably 98°C, particularly preferably 97°C, and most preferably 95°C. If container 10 is a closed container, the temperature inside container 10 can be heated to 100°C or higher (e.g., 100°C or higher and 110°C or lower).

[0053] If under pressurized conditions, the temperature inside container 10 during the cleaning process (process (S2)) is preferably above 100°C and below 120°C.

[0054] The higher the temperature of the aqueous medium, the easier it is for the water-soluble adhesive to dissolve in the aqueous medium, therefore it is preferred.

[0055] By performing the cleaning process (process (S2)) under high temperature conditions in the aqueous medium, water-soluble binders can be easily removed from the molding sand even if there are pores and / or unevenness on the surface of the molding sand, which is therefore preferred.

[0056] The circumferential speed of the front end of the stirring blade 21 in the cleaning process (process (S2)) is not particularly limited, but is preferably 1 m / s or more and 15 m / s or less. The upper limit is more preferably 12 m / s, particularly preferably 10 m / s, and most preferably 8 m / s.

[0057] There is no particular limitation on the time of the cleaning process (process (S2)), but it is preferably 5 minutes or more and 30 minutes or less. The lower limit is more preferably 10 minutes. The upper limit is more preferably 20 minutes.

[0058] If the agitator 20 is stopped after the washing process (process (S2)), the molding sand has a higher specific gravity relative to the aqueous medium, resulting in greater friction between the sand particles. Therefore, the molding sand can settle due to gravity within the container 10. As a result, ... Figure 3 As shown in the left figure, a wetted molding sand WS containing settled molding sand and an aqueous medium containing dissolved water-soluble binder can be formed on the lower side of the container 10. In addition, a supernatant L (liquid phase) without molding sand, consisting of an aqueous medium containing dissolved water-soluble binder, can be formed on it.

[0059] If the agitator 20 is operated at a low speed after the cleaning process (process (S2)), the molding sand has a higher specific gravity relative to the aqueous medium, resulting in greater friction between the sand particles. Therefore, within the container 10, the molding sand can accumulate into a mortar shape due to gravity and centrifugal force. As a result, as... Figure 3 As shown in the right figure, a mortar-shaped moistened molding sand WS containing molding sand and an aqueous medium containing dissolved water-soluble binder can be formed on the lower side inside the container 10. Additionally, a supernatant L (liquid phase) consisting of the aqueous medium containing dissolved water-soluble binder and free of molding sand, which is composed of the mortar-shaped moistened molding sand WS, can be formed within the recess of this mortar-shaped moistened molding sand WS. Sometimes, a supernatant L (liquid phase) consisting of the aqueous medium containing dissolved water-soluble binder may also be formed on top of this supernatant.

[0060] In this embodiment, as described above, by utilizing the difference in specific gravity between molding sand and aqueous medium, solid-liquid separation can be achieved in container 10 through a simple operation such as stopping or slowing down the stirring device 20 after the cleaning process (process (S2)).

[0061] Furthermore, the term "low-speed operation" here refers to operation at a slower stirring speed than that in the cleaning process (process (S2)).

[0062] The molding sand recycling device 1 includes a draining device 70, which drains at least a portion of the liquid component from the mixture of molding sand composition and aqueous medium present in the container 10 after the molding sand composition and aqueous medium are stirred and mixed in the container 10.

[0063] The “liquid components” mentioned here include aqueous media and water-soluble adhesives dissolved in them.

[0064] The drainage device 70 may include a portion of a drainage pipe 71 inserted into the container 10 and a drainage pump 72 connected to the drainage pipe 71.

[0065] The drain pipe 71 has a liquid inlet 71A for liquid entry, a portion of which is inserted into the supernatant L (liquid phase) formed by the stopping or low-speed operation of the agitator 20, which consists of an aqueous medium containing a water-soluble binder. The liquid inlet 71A is positioned to prevent the intake of molding sand.

[0066] The liquid inlet 71A is preferably located on or near the central axis AX1 (stirring shaft of stirring device 20) of container 10 (e.g., within 5 cm of the central axis AX1). The height of the liquid inlet 71A of the drain pipe 71 can vary depending on the water level of the supernatant L (liquid phase).

[0067] The drain pipe 71 is preferably able to extend from the inside of the container 10 through the top cover 12 of the container 10 to the outside of the container 10.

[0068] The drain pipe 71 may be made of metal piping, hoses or a combination thereof.

[0069] The draining device 70 may also include one or more other elements such as valves and flow meters as needed.

[0070] In the molding sand recycling apparatus 1, after the molding sand composition fed into the container 10 is stirred and mixed with an aqueous medium, a drainage process (step (S3)) is performed by the drainage device 70 to discharge at least a portion of the liquid components from the mixture of molding sand composition and aqueous medium present in the container 10. Through this operation, a separation process is performed to separate and remove most of the aqueous medium containing dissolved water-soluble binders from the mixture of molding sand composition and aqueous medium fed into the container 10.

[0071] In this embodiment, without removing the wet sand from container 10 or using a separation device such as a filter, most of the aqueous medium containing the water-soluble adhesive can be separated and removed through simple operations such as solid-liquid phase separation and drainage.

[0072] However, as needed, a known filter may be installed at or near the liquid inlet 71A of the drain pipe 71 to prevent molding sand from being sucked into the drain pipe 71.

[0073] Alternatively, the draining process (process (S3)) can be performed without stirring the contents of container 10 (the mixture of molding sand composition and aqueous medium), or the draining process (process (S3)) can be performed while stirring the contents of container 10 (the mixture of molding sand composition and aqueous medium) at a low speed using stirring device 20.

[0074] There is no particular limitation on the circumferential speed of the front end of the stirring blade 21 in the draining process (process (S3)). However, relative to the circumferential speed of the front end of the stirring blade 21 in the cleaning process (process (S2)), it is preferably 1 / 2 or less, more preferably 1 / 3 or less, particularly preferably 1 / 5 or less, and most preferably 1 / 8 or less.

[0075] In the draining process (process (S3)), the circumferential speed of the leading edge of the stirring blade 21 is preferably 0 m / s or more and 1.5 m / s or less. The lower limit is more preferably 0.1 m / s. The upper limit is more preferably 1.2 m / s, particularly preferably 1.0 m / s, and most preferably 0.8 m / s.

[0076] From the viewpoint of improving the removal efficiency of water-soluble adhesives, it is preferable to perform the draining process (process (S3)) while heating or adjusting the temperature of the container 10 using a heating or temperature control device 81. The temperature inside the container 10 during the draining process (process (S3)) is not particularly limited, but is preferably 40°C or higher and 100°C or lower. The lower limit is more preferably 50°C, further preferably 60°C, even more preferably 70°C, particularly preferably 80°C, and most preferably 90°C. The upper limit is more preferably 99°C, further preferably 98°C, particularly preferably 97°C, and most preferably 95°C.

[0077] The time for the drainage process (process (S3)) is not particularly limited, but is preferably 1 minute or more and 15 minutes or less. The lower limit is more preferably 2 minutes. The upper limit is more preferably 10 minutes, and particularly preferably 5 minutes.

[0078] After the above-mentioned drainage process (process (S3)), a residue containing molding sand and liquid components that could not be drained remains in the container 10 (wet molding sand WS).

[0079] The amount of water in the residue (wet molding sand WS) remaining in container 10 after the drainage process (process (S3)) is not particularly limited, but can be more than 10% by mass and less than 30% by mass relative to 100% by mass of molding sand. The lower limit can be 12% by mass or 15% by mass. The upper limit is preferably 25% by mass, and more preferably 20% by mass.

[0080] The molding sand regeneration device 1 includes a drying device 80, which 80 dries the molding sand-containing residue (wet molding sand WS) remaining in the container 10 after the liquid discharge process (process (S3)).

[0081] In the molding sand recycling apparatus 1, a drying process (process (S4)) is performed to dry the residue (wet molding sand WS) containing molding sand remaining in the container 10 after the liquid discharge process (process (S3)). Through this operation, the liquid components are dried and removed, and recycled molding sand is obtained.

[0082] Examples of drying methods include heat drying, vacuum drying, and vacuum heating drying.

[0083] In the case of heat drying, the drying apparatus 80 may include a heating or temperature control device 81 for heating or temperature control inside the container 10.

[0084] In the case of vacuum drying, the drying apparatus 80 may include a pressure reducing device 82 for reducing the pressure inside the container 10. The pressure reducing device 82 may include an exhaust pipe 82A connected to the container 10 and a vacuum pump 82B connected to the exhaust pipe 82A. The pressure reducing device 82 may include one or more other elements such as valves, pressure gauges, and heat exchangers as needed.

[0085] In the case of depressurized heating drying, the drying apparatus 80 may include the heating or temperature control device 81 and the depressurization device 82 described above.

[0086] The heating or temperature control device 81 can use known devices. For example, the heating or temperature control device 81 may include a sleeve covering at least a portion of the container body 11 and allowing fluids such as cold water, warm water, steam, and oil to flow inside, as well as a temperature control device that controls the temperature of the fluid flowing within the sleeve using known methods as needed. By selecting the temperature of the fluid flowing within the sleeve, the container 10 can be heated, temperature-controlled, or cooled.

[0087] In vacuum drying or vacuum heating drying, high-temperature heating is not required, and the cooling process after the drying process can be eliminated or shortened, which is preferred.

[0088] For example, when drying is carried out under reduced pressure (below 95 kPa), drying can be performed at a relatively low temperature (above 30°C and below 50°C).

[0089] From the viewpoint of improving drying efficiency, it is preferable to perform the drying process (process (S4)) while stirring the residue using the stirring device 20.

[0090] The circumferential speed of the front end of the stirring blade 21 in the drying process (process (S4)) is not particularly limited, but is preferably 1 m / s or more and 15 m / s or less. The upper limit is more preferably 12 m / s, particularly preferably 10 m / s, and most preferably 8 m / s.

[0091] While the residue is being stirred using the stirring device 20 and a drying process (process (S4)) is being carried out, the molding sand can be ground by colliding with each other in the presence of appropriate moisture.

[0092] Grinding molding sand can smooth its surface and improve the strength of molds using recycled molding sand, making it a preferred method.

[0093] At the beginning of the drying process (process (S4)), a small amount of water-soluble adhesive may sometimes remain on the surface of the molding sand. In this case, it is preferable to physically remove the small amount of water-soluble adhesive remaining on the surface of the molding sand by grinding the molding sand.

[0094] Furthermore, Patent Document 1 listed in the [Background Art] section does not disclose a technique for efficiently performing the cleaning, separation, and drying processes within a single container. This document also does not disclose a technique for performing the drying process while simultaneously stirring the residue. The drying process in this document does not also function as a grinding process, and therefore fails to achieve the effect of smoothing the surface of the molding sand and physically removing the small amount of water-soluble adhesive remaining on the surface of the molding sand during the drying process.

[0095] Perform a drying process (process (S4)) until the moisture content in the recycled molding sand is sufficient for mold making.

[0096] There is no particular restriction on the amount of water in the wet molding sand at the start of the drying process (process (S4)). It can be more than 10% and less than 30% by mass relative to 100% of the molding sand.

[0097] The moisture content in the recycled molding sand obtained after the drying process (process (S4)) is not particularly limited, but is preferably 0% by mass or more and 1.0% by mass or less relative to 100% by mass of the molding sand. The upper limit is more preferably 0.9% by mass, further preferably 0.8% by mass, particularly preferably 0.7% by mass, and most preferably 0.5% by mass. The lower limit can be 0.05% by mass or 0.1% by mass.

[0098] The drying process (process (S4)) is not particularly limited in time, but is preferably 15 minutes or more and 60 minutes or less. The lower limit is more preferably 20 minutes. The upper limit is more preferably 50 minutes, and particularly preferably 40 minutes.

[0099] As described above, when the drying process (process (S4)) is carried out while the residue is stirred using the stirring device 20, the drying process (process (S4)) can also be used as a grinding process during the period when there is a moderate amount of moisture in the drying process (process (S4)).

[0100] For example, during the period when the moisture content relative to 100% by mass of the molding sand is preferably 5% or more and 30% or less by mass, more preferably 6% or more and 25% or less by mass, and particularly preferably 6% or more and 20% or less by mass, the drying process (process (S4)) can also be used as a grinding process.

[0101] In the molding sand regeneration apparatus 1 and the molding sand regeneration method using the molding sand regeneration apparatus 1, other known grinding processes can be performed after the drying process (process (S4)) instead of the above-described method. In this case, other grinding processes can also be performed in the same container 10.

[0102] The recycled molding sand obtained after the drying process (process (S4)) can be cooled in container 10 as needed. The cooling method can be natural cooling or forced cooling using a heating or temperature control device 81.

[0103] The processing device 2 may include a discharge section 40 for discharging the final recycled molding sand. The discharge section 40 includes a discharge outlet 41 and an on / off valve 42 for opening and closing it, and may also include a discharge path 43 if necessary. The discharge outlet 41 may be located at a lower position on the side of the container body 11. The discharge path 43 may extend obliquely downward from the discharge outlet 41.

[0104] In the molding sand recycling device 1, by opening the on / off valve 42 to open the outlet 41, the discharge process (process (S5)) can be carried out to discharge the finally obtained recycled molding sand to the outside through the outlet 41 and the discharge path 43.

[0105] like Figure 4 As shown in the flowchart, the molding sand regeneration method of this disclosure includes: a step of adding a molding sand composition and an aqueous medium into a container 10 (S1); a step of mixing the molding sand composition added into the container 10 with the aqueous medium (S2); a step of discharging at least a portion of the liquid component from the mixture of the molding sand composition and the aqueous medium present in the container 10 after step (S2) (S3); and a step of drying the residue containing molding sand remaining in the container 10 while stirring after step (S3) (S4).

[0106] Sometimes, a small amount of water-soluble binder adheres to the molding sand after step (S3). Therefore, in order to remove the residual water-soluble binder, water-based medium can be added to container 10 again after step (S3) if necessary, and then steps (S2) and (S3) can be repeated. In addition, as needed, the addition of water-based medium and the re-implementation of steps (S2) and (S3) can be repeated more than once.

[0107] In the molding sand regeneration method disclosed herein, step (S4) can also serve as a grinding process.

[0108] The molding sand regeneration method disclosed herein may also include, as needed, a step of performing a known grinding process after step (S4).

[0109] The molding sand regeneration method disclosed herein may include, as needed, a step of cooling the obtained regenerated molding sand in container 10 after step (S4).

[0110] The molding sand regeneration method disclosed herein may include a final step (S5) in which the obtained regenerated molding sand is discharged from container 10.

[0111] According to the molding sand regeneration apparatus 1 and molding sand regeneration method disclosed herein, the cleaning process, separation process and drying process can be carried out efficiently in a container 10.

[0112] In the technology disclosed herein, after the cleaning process is completed, it is not necessary to remove the wet sand containing water-based media that is difficult to handle from the container, nor is it necessary to perform time-consuming, labor-intensive, and costly operations such as removing the wet sand from the container and conveying the wet sand to the next process.

[0113] According to the technology disclosed herein, the molding sand can be ground simultaneously with and / or after the drying process within the same container 10, as needed.

[0114] According to the technology disclosed herein, the obtained recycled molding sand can be cooled within the same container 10 as needed.

[0115] According to the technology disclosed herein, all the processes required for regenerating molding sand from a molding sand composition containing molding sand and a water-soluble binder can be carried out efficiently within a container 10.

[0116] As explained above, according to this embodiment, a molding sand regeneration apparatus and a molding sand regeneration method can be provided that can efficiently perform the cleaning process, the separation process and the drying process.

[0117] This invention is not limited to the embodiments described above. Design changes can be made appropriately without departing from the spirit and scope of the invention. These changes should not be considered as departing from the spirit and scope of the invention, and all modifications readily conceived by those skilled in the art are included within the scope of the appended claims.

Claims

1. A molding sand recycling apparatus for recycling molding sand from a molding sand composition comprising molding sand and a water-soluble binder, comprising a container, a stirring device, a draining device, and a drying device. The molding sand composition and the aqueous medium are added into the container. The stirring device mixes the molding sand composition and the aqueous medium that are added to the container. The drainage device discharges at least a portion of the liquid component from the mixture of the molding sand composition and the aqueous medium present in the container after the mixing. The drying apparatus includes a heating or temperature control device for heating or adjusting the temperature inside the container and / or a pressure reduction device for reducing the pressure inside the container, and dries the residue containing the molding sand remaining in the container after the liquid is drained. The molding sand recycling device simultaneously stirs the residue using the stirring device and dries the residue using the drying device.

2. The molding sand regeneration device according to claim 1, After the stirring and mixing, the stirring of the stirring device is stopped or set to low speed. After the stirring and mixing, the mixture of the molding sand composition and the aqueous medium in the container is subjected to solid-liquid phase separation, and the liquid component is drained from the liquid phase obtained by the solid-liquid phase separation.

3. The molding sand regeneration device according to claim 2, The drainage device includes a portion of a drainage pipe inserted into the container and a drainage pump connected to the drainage pipe. The liquid inlet of the drain pipe is inserted into the liquid phase obtained through the solid-liquid phase separation.

4. A method for regenerating molding sand, comprising the steps of regenerating molding sand from a molding sand composition containing molding sand and a water-soluble binder: Step S1: The molding sand composition and aqueous medium are added into a container; Step S2: Stirring and mixing the molding sand composition and the aqueous medium that are put into the container; Step S3, following step S2, involves discharging at least a portion of the liquid component from the mixture of the molding sand composition and the aqueous medium present in the container; and Step S4 is a process of drying the residue containing the molding sand remaining in the container while stirring, following step S3.

5. The molding sand regeneration method according to claim 4, After step S2, the stirring is stopped or set to low speed. After step S2, the mixture of molding sand composition and aqueous medium in the container is subjected to solid-liquid phase separation. In step S3, the liquid components are drained from the liquid phase obtained by the solid-liquid phase separation.

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