Reclaiming waste sand

Abstract

In the method for reclaiming waste sand containing bentonite binder, the waste sand is heat-treated to remove carbon and absorbed moisture from the bentonite binder in the waste sand, the heat-treated waste sand is mechanically treated to mechanically separate the sand from the bentonite binder, and a cooling effect is imparted to the sand separated from the bentonite binder.Furthermore, a reclaiming device for waste sand containing bentonite binder, sand for construction industry products, foundry sand, or power plant boiler sand, and the use of the reclaimed sand in construction industry products, foundry sand, or power plant boiler sand are introduced.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for reclaiming waste sand containing a bentonite binder. [Background technology]

[0002] In prior art methods, waste sand containing bentonite binder, such as sand used in foundries, is thermally regenerated by using so-called fluidized bed boilers, in which a strong air current is applied from the bottom upwards to the furnace of the boiler, which washes the waste sand and suspends the ash and fuel used for heating in the furnace of the boiler.

[0003] The reclamation of waste sand offers the advantage of potentially reducing the need for virgin natural sand. However, the fluidized bed boiler-based reclamation process described above has the disadvantages of being slow, expensive to operate, and producing a large amount of waste per ton of recycled sand washed.

[0004] From an ecological perspective, it makes sense to develop reclamation processes so that the need for virgin natural sand can be further reduced and the energy consumption used in the reclamation process can be reduced. Summary of the Invention

[0005] It is an object of the present invention to provide a novel method and apparatus for reclaiming waste sand containing bentonite binder so that the washed sand can be reused as construction industry products or foundry sand.

[0006] The invention is characterized by the features of the independent claims.

[0007] The present invention is based on the idea of ​​combining the effects of thermal and mechanical treatment on waste sand containing bentonite binder in order to reclaim the sand for further use.

[0008] The advantages of the present invention are reduced energy consumption and increased yield of washed and reclaimed sand.

[0009] Some embodiments of the invention are disclosed in the dependent claims. [Brief explanation of the drawings]

[0010] The present invention will now be described in more detail by way of preferred embodiments with reference to the accompanying drawings.

[0011] [Figure 1] 1 shows a schematic side view of an apparatus according to an embodiment for the reclamation of waste sand containing bentonite binder. [Figure 2] 2 shows a schematic end view of a portion of the apparatus of FIG. 1; [Figure 3] 2 shows a schematic, partially cut-away side view of a portion of the apparatus of FIG. 1; [Figure 4] 2 shows a schematic, partially cut-away side view of a portion of the apparatus of FIG. 1; [Figure 5] 1 shows a schematic diagram of a method according to an embodiment for the reclamation of waste sand containing bentonite binder.

[0012] For clarity, these figures depict some embodiments of the present invention in a simplified manner, in which like reference numerals identify like elements. DETAILED DESCRIPTION OF THE INVENTION

[0013] 1 shows a schematic side view of an apparatus 1 for the reclamation of waste sand containing bentonite binder according to one embodiment. The waste sand containing bentonite binder consists of sand grains having a layer of bentonite binder on their surface. The waste sand containing bentonite binder can come from, for example, a foundry where it was used for casting, or from a power plant where it was used as bed material for a fluidized bed boiler.

[0014] The apparatus 1 includes a rotatable (rotary) furnace (rotary furnace) 2. The furnace 2 is heated to impart a heat treatment effect to the waste sand containing the bentonite binder in order to remove carbon and absorbed moisture from the bentonite binder in the waste sand. Figure 2 shows a schematic end view of the furnace 2 of Figure 1. The furnace 2 is arranged to be rotated by at least one rotary motor 3, for example, in the direction of rotation indicated by the arrow with reference symbol RD in Figure 2.

[0015] The rotatable furnace 2 has a generally cylindrical shape. The furnace 2 has a first end 2a and a second end 2b opposite the first end 2a. The direction connecting the first end 2a and the second end 2b of the furnace 2 defines the longitudinal direction of the furnace 2. The furnace 2 has a first end region 2a' extending from the first end 2a toward the second end 2b. In the embodiment of FIG. 1, the first end region 2a' extends substantially to the center of the furnace 2 in the longitudinal direction. The first end region 2a' also includes the first end 2a of the furnace 2. The furnace 2 further has a second end region 2b' extending from the second end 2b toward the first end 2a. In the embodiment of FIG. 1, the second end region 2b' extends substantially to the center of the furnace 2 in the longitudinal direction. The second end region 2b' also includes the second end 2b of the furnace 2. The furnace 2 has a first end 2a or a first end region 2a', which is designated by the reference F WS‐IN The furnace 2 has at least one inlet 4 for feeding waste sand into the furnace 2 as indicated by the arrow in the figure. The furnace 2 has a second end 2b or second end region 2b' at its second end 2b, which is denoted by the reference D TTWS‐OUT As indicated by the arrow, the furnace 2 has at least one outlet 5 for discharging the waste sand that has been heat-treated in the furnace 2, i.e., the heat-treated waste sand containing the bentonite binder, from the furnace 2 for further processing. Thus, the interior space (internal volume) of the furnace 2 is at least partially open substantially from the first end 2a to the second end 2b of the furnace 2 for the flow of waste sand within the furnace.

[0016] One or more lifters 6 are provided on the inner periphery of the rotatable furnace 2 in at least a portion of the first end region 2a' of the rotatable furnace 2. As shown schematically in FIG. 2, the lifters 6 extend from the inner periphery of the rotatable furnace 2 toward the center of the furnace 2. In FIG. 1, the lifters 6 are shown very diagrammatically by dashed lines designated by the reference numeral 6. In the longitudinal direction of the furnace 2, the at least one lifter 6 is arranged to extend substantially from the first end 2a of the furnace 2 toward the second end 2b of the furnace 2. The at least one lifter 6 may extend to the second end region 2b' of the furnace 2 as shown schematically in FIG. 1, or may even extend to the second end 2b of the furnace 2.

[0017] At least one lifter 6 is provided to capture at least a portion of the waste sand fed into the furnace 2 and move together with the furnace 2 on the inner periphery of the furnace 2 until the waste sand falls toward the bottom of the furnace 2 as indicated schematically by the arrow with reference sign FA in Fig. 2. As the waste sand falls toward the bottom of the furnace 2, the falling waste sand, i.e., the waste sand particles, form a kind of sand cloud inside the furnace 2 as they fall, as indicated schematically by a number of dots in Fig. 2. The layer of waste sand between the lifters 6 is indicated very schematically by reference sign WS.

[0018] In the embodiment of FIG. 1 , the lifter 6 is in an inclined position such that the end of the lifter 6 facing the first end 2 a of the furnace 2 is positioned higher than the opposite end of the lifter 6 facing the second end 2 b of the furnace 2. The effect of this is to guide and promote the movement of waste sand within the furnace 2 from the first end 2 a of the furnace 2 toward the second end 2 b of the furnace 2. A similar effect can be achieved or enhanced by placing the furnace 2 in an inclined position such that the first end 2 a of the furnace 2 is positioned higher than the second end 2 b of the furnace 2, as shown schematically in the embodiment of FIG. 1 .

[0019] 1, at least one burner 7 is provided at the first end 2a of the furnace 2. Alternatively, in some cases, the burner 7 may be arranged in the interior space of the furnace 2, in the first end region 2a' of the furnace 2. The burner 7 is configured to heat the interior space of the furnace 2 and the waste sand supplied into the furnace 2. The burner 7 may be, for example, a gas burner, a condensing gas burner, or any other burner or heating means applicable to heating the interior space of the furnace 2 and the waste sand supplied into the furnace 2.

[0020] 1, at least one exhaust device 8 is provided at the second end 2b of the furnace 2. Alternatively, in some cases, the exhaust device 8 may be arranged in the interior space of the furnace 2, in the second end region 2b' of the furnace 2. The exhaust device 8 is provided to discharge flue gas and fine particles such as dust generated in the interior space of the furnace 2 to the outside of the furnace 2. The exhaust device 8 may be replaced by other means applicable for discharging flue gas and fine particles from the furnace 2.

[0021] The furnace 2 and its associated equipment operate as follows.

[0022] The waste sand containing bentonite binder is shown by arrow F in Figure 1. WS-IN As shown schematically in FIG. 1, the waste sand is fed into the furnace 2 through at least one inlet 4. The waste sand is preferably fed into the furnace 2 so that it falls through the flame of the burner 7 towards the bottom of the furnace 2, which effectively begins heating the waste sand.

[0023] At the same time, the furnace 2 is rotated by the rotary motor 3, and at least one lifter 6 is arranged to capture at least a portion of the waste sand supplied to the furnace 2 and move together with the furnace 2 on the inner periphery of the furnace 2 until the waste sand falls toward the bottom of the furnace 2. This causes the waste sand particles to form a sand cloud inside the furnace 2. The formation of this sand cloud allows the waste sand to be heated almost uniformly in the interior space of the furnace 2. The burner 7 is set and operated to heat the waste sand so that a waste sand temperature of at least about 400°C, preferably at least about 400 to 700°C, is achieved. To ensure that the desired temperature of the waste sand in the furnace 2 can be achieved, a temperature sensor for measuring the temperature of the waste sand in the furnace 2 may be applied to control the heating efficiency of the burner 7 and / or the rotation speed of the furnace 2 (which affect both the formation of a sand cloud in the interior space of the furnace 2 and the diffusion speed (propagation speed) of the waste sand within the furnace 2).

[0024] Heating the waste sand thermally processes the waste sand in the furnace 2, allowing absorbed moisture to evaporate from the bentonite binder. Once the absorbed moisture has evaporated from the bentonite binder, the waste sand is subjected to mechanical processing that facilitates the release of the bentonite binder from the surfaces of the sand grains, as will be discussed in more detail below.

[0025] As the furnace 2 rotates, at least a portion of the waste sand is captured by at least one lifter 6 and moves with the furnace 2 on the inner periphery of the furnace 2 until it falls toward the bottom of the furnace 2. The impact of the falling sand particles on the bottom of the furnace 2 imparts a mild mechanical treatment effect to the heated waste sand. This mild mechanical treatment effect separates the carbon-containing dust from the bentonite binder. The carbon separated from the bentonite binder is burned by the temperature inside the furnace 2, reducing the amount of dust generated during the process.

[0026] Fine particles such as dust generated in the furnace 2 or introduced into the furnace 2 together with the waste sand are exhausted to the outside of the furnace 2 by an exhaust device 8. The waste sand that has been subjected to the thermal treatment effect in the furnace 2 is then exhausted to the outside of the furnace 2 by the mechanical treatment effect applied to the waste sand as will be explained below. TTWS‐OUTThe gas is discharged out of the furnace 2 through at least one outlet 5 as indicated diagrammatically by the arrow.

[0027] The apparatus 1 of Figure 1 further comprises a rotatable drum 9 for applying a mechanical treatment effect to the heat-treated waste sand received from the rotatable furnace 2 to separate the sand, i.e., sand grains, from the bentonite binder in the waste sand. The drum 9 is configured to be rotated by at least one rotary motor 10.

[0028] The rotatable drum 9 has a generally cylindrical shape and includes a first end 9a and a second end 9b opposite the first end 9a. The direction connecting the first end 9a and the second end 9b of the drum 9 defines the longitudinal direction of the drum 9. The drum 9 includes a first end region 9a' extending from the first end 9a toward the second end 9b to substantially the center of the drum 9 in the longitudinal direction. The first end region 9a' comprises the first end 9a of the drum 9. The drum 9 further includes a second end region 9b' extending from the second end 9b toward the first end 9a to substantially the center of the drum 9 in the longitudinal direction. The second end region 9b' comprises the second end 9b of the drum 9. The drum 9 includes a portion at the first end 9a or the first end region 9a' designated by the reference symbol F. TTWS‐IN As shown by the arrow in the figure, the drum 9 has at least one inlet 11 for feeding the heat-treated waste sand from the rotatable furnace 2 into the rotatable drum 9. The drum 9 has a second end 9b or second end region 9b' at its second end 9b, which is denoted by the reference D CNS‐OUT As shown by the arrow, the drum 9 has at least one outlet 12 for discharging the sand separated from the bentonite binder, i.e., the reclaimed clean sand, out of the drum 9. The apparatus 1 may further comprise a conveyor (such as, for example, a belt conveyor 13 or a screw conveyor) for transporting the reclaimed clean sand for further processing, including, for example, packaging of the reclaimed sand.

[0029] The rotatable drum 9 includes at least one section 14, at least in a first end region 9a', for mechanically treating the heat-treated waste sand to mechanically separate the sand, i.e., sand grains, from the bentonite binder in the waste sand. FIG. 3 is a side view of a portion of the rotatable drum 9, partially broken away and schematically showing the section 14 for mechanically treating the waste sand. In the embodiment of FIG. 3, the section 14 is a grinding section having a plurality of grinding balls 15 that impact the waste sand to separate it from the bentonite binder when the drum 9 is rotated by the rotary motor 10. Thus, the section 14 provides a mechanical treatment means applicable to mechanically treating the heat-treated waste sand to separate it from the bentonite binder. The impact of the sand grains and their abrasion against each other causes the bentonite binder to peel off from the surface of the sand grains, thereby forming a dust cloud containing the bentonite binder and other fines in the grinding section 14 within the drum 9.

[0030] According to one embodiment of the device 1, at least one similar section may be arranged in at least the second end region 2b' of the rotatable furnace 2, as shown schematically in FIG. 1 by reference number 14 located in the second end region 2b' of the rotatable furnace 2.

[0031] The inner periphery of the rotatable drum 9 may be provided with one or more lifters 16 extending from the inner periphery towards the center of the drum 9 in at least a portion of at least one of the first end region 9a' and second end region 9b' of the drum 9 in a manner similar to the lifters 6 (see FIG. 2) described above in relation to the rotatable furnace 2. In FIG. 1, the lifters 16 are indicated very diagrammatically by dashed lines with reference numeral 16.

[0032] At least one lifter 16 in the rotatable drum 9 is arranged to capture at least a portion of the sand in the drum 9 and move it therewith along the inner periphery of the drum 9 until it falls toward the bottom of the drum 9 (in a manner similar to the sand indicated diagrammatically by the arrow FA in FIG. 2). As the sand falls toward the bottom of the furnace 2, the falling sand that has separated from the bentonite binder (i.e., the sand grains from which the bentonite binder has been separated), together with fines including, for example, the bentonite binder and other dust that have been separated from the sand, form a sort of cloud inside the drum 9 in a manner similar to that described above in relation to the rotatable furnace 2 (see FIG. 2).

[0033] In the embodiment of FIG. 1, the lifter 16 is also in an inclined position to promote longitudinal movement of sand within the drum 9. In the inclined position of the lifter 16, the end of the lifter 16 facing the first end 9a of the drum 9 is higher than the opposite end of the lifter 16 facing the second end 9b of the drum 9. A similar effect can be achieved or enhanced by placing the drum 9 in an inclined position such that the first end 9a of the drum 9 is higher than the second end 9b of the drum 9, as also shown schematically in the embodiment of FIG. 1.

[0034] Furthermore, in the apparatus of FIG. 1 , at least one exhaust device 17 is provided at the first end 9a of the drum 9. Alternatively, in some cases, the exhaust device 17 may be located in another portion of the drum 9's first end region 9a's interior space (volume). The exhaust device 17 is provided to generate an air flow within the drum 9. The direction of this air flow is from the second end 9b of the drum 9 toward the first end 9a of the drum 9. This air flow cools the sand, i.e., the sand grains, separated from the bentonite binder. At the same time, the exhaust device 17 may exhaust fine particles, such as dust, from the interior space of the drum 9 to the outside of the drum 9 along with the air flow intended to cool the sand separated from the bentonite binder.

[0035] Thus, the exhaust device 17 provides a type of cooling means for cooling the sand separated from the bentonite binder by a flow of unheated air through the interior space of the drum 9. The unheated air flow enters the drum 9 through at least one air inlet 18. The at least one air inlet 18 is located at the second end 9b of the drum 9 or in another part of the second end region 9b' of the drum 9 to allow cooled air to flow into the drum 9 from the ambient air. The drive power of the exhaust device 17 is controlled so that fines, including the bentonite binder separated from the sand grains and other dust but not the sand separated from the bentonite binder, can be removed from the drum 9 along with the cooled air flowing through the drum 9. If specially cooled air is available around the apparatus 1, that cooled air can also be used for the unheated air flow through the interior space of the drum 9.

[0036] 1 is further provided with at least one section 19 in the second end region 9b' of the drum 9, which comprises at least one classifier 20. The at least one classifier 20 separates the sand separated from the bentonite binder into at least one pass fraction D. CNS‐OUT and at least one rejection fraction RF. CNS‐OUT is discharged from the drum 9 through at least one outlet 12 of the drum 9 as washed reclaimed sand. At least one reject fraction RF is discharged from the drum 9 for further processing. CNS‐OUT The flow of the pass fraction D) and the flow of the reject fraction RF are shown schematically by arrows in Figures 1 and 4, respectively. Referring to Figure 4, which is a partially cutaway schematic side view of section 19 of drum 9 in Figure 1, a mesh 21 (classifier 20) having a plurality of shaker units (vibration units) 22 is shown. The mesh 21 can be shaken (vibrated) by the shaker units 22. In this embodiment, the mesh 21 forms a type of classifier 20. As defined by the mesh size of the mesh 21, at least a portion of the sand, i.e., sand grains smaller than a predetermined particle size, are classified as the pass fraction D CNS‐OUTThis pass fraction D is separated or filtered from the processed sand in the drum 9 through the openings of the mesh 21 to form this pass fraction D. CNS‐OUT That is, the washed reclaimed sand can be reused for various purposes, as described below.

[0037] Furthermore, in the apparatus of Figure 1, the mesh 21 is provided with one or more magnetic separators 23 for removing magnetic particles (e.g., iron and steel particles) from the sand separated from the bentonite binder. For example, in the embodiment of Figure 3, three magnetic separators 23 are provided. In the configuration of Figure 4, one magnetic separator 23 is provided above the mesh 21 and two magnetic separators 23 are provided below the mesh 21 at either end of the mesh 21, although the arrangement of the mesh 21 and the magnetic separators 23 can be changed as needed.

[0038] Sand that enters but does not pass through mesh 21 becomes the reject fraction RF and is discharged out of drum 9 for reject (waste) disposal. In practice, the reject fraction RF is also sand or is made up of sand particles having a particle size that has been separated from the bentonite binder but does not pass through the openings in mesh 21. Reject disposal may include, for example, sorting the reject fraction RF into further fractions of different particle sizes.

[0039] The solution disclosed herein provides a combination of thermal and mechanical treatments for waste sand containing a bentonite binder to reclaim the sand for further use. After the waste sand containing a bentonite binder is thermally treated, the sand grains are mechanically treated to facilitate the release of the bentonite binder from the grain surface. The method and apparatus disclosed herein provide a continuous process in which operating conditions remain substantially constant, but can, of course, be adjusted in response to variations in the quality of the waste sand being reclaimed. Adjustable factors may be, for example, at least one of the heating efficiency of the burner 7, the rotational speed of the furnace 2, or the drive power of the exhaust device 17. However, other factors related to the operation of some equipment in the process and that significantly affect the operation of the process may also be determined to be adjustable factors of the process. For example, considering sand used in foundries in more detail, the sand closest to the molten metal in the casting process is exposed to very high temperatures (over 1400°C). At high temperatures, bentonite loses all of its crystal water and becomes calcined bentonite, which cannot reabsorb water. In many sand cycles, a new clay layer that has lost its crystal water forms on top of the calcined sand grains, and this sand becomes like an egg mass.

[0040] Thermal methods alone are not effective in regenerating sand grains that have become egg-shaped. At high temperatures, the same phenomenon occurs as during casting: activated bentonite is baked to the surface of the sand grains. Although baked bentonite is brittle, heat alone is not enough to break the bond between the sand grains and the bentonite. Therefore, even after thermal regeneration, mechanical treatment is required to provide sufficient mechanical impact to the waste sand being processed.

[0041] The thermomechanical method disclosed herein significantly enhances regeneration because prolonged exposure to high temperatures ensures that most of the bentonite bonded to the sand sinters, making it unable to withstand mechanical shocks intended to break the bond between the sand grains and the bentonite.

[0042] Mechanical treatment provides an effective method for mechanically removing the bentonite binder from the waste sand after the absorbed moisture has evaporated from the bentonite binder. The total amount of energy used in the regeneration process is less than, for example, a regeneration process based on a fluidized bed boiler, because in the solution disclosed herein, the thermal treatment is not aimed at separating the bentonite binder from the sand grains, but only at improving the efficiency of the mechanical treatment stage. Thanks to the mechanical treatment, the yield of washed regenerated sand is increased compared to a regeneration process based on a fluidized bed boiler.

[0043] In the embodiment of Figure 1, the rotary drum 9 is positioned below the rotary furnace 2 and substantially parallel to it in the horizontal direction. This embodiment provides a compact combination of the furnace 2 and the drum 9. Also, depending on the size of the furnace 2 and the size of the drum 9, this embodiment may be easily mounted on a chassis with multiple wheels, which allows the combination of the furnace 2 and the drum 9 to be easily moved as required. However, other arrangements of the furnace 2 and the drum 9 relative to each other are possible.

[0044] According to one embodiment, the device comprises at least one crusher, crusher or sieve for crushing, breaking or removing lumps that may appear in the waste sand fed to the furnace 2.

[0045] According to one embodiment, the device comprises a heat recovery unit for recovering heat from the air stream removed from at least one of the furnace 2 or drum 9 by at least one exhauster 8, 17. The recovered heat may be used, for example, for drying or preheating the waste sand fed to the furnace 2.

[0046] According to one embodiment, the reclaimed sand may be reused as foundry sand or power plant boiler sand, either as is or mixed with virgin natural sand. The reclaimed sand may be recoated with a binder suitable for the particular application.

[0047] According to one embodiment, reclaimed sand may be used in construction industry products such as concrete products, mortar, floor mass products, fillers, floats, acrylic mass, or as filter sand. Reclaimed sand is more suitable for use in construction industry products than virgin natural sand because of its rounded grain structure, which can provide a more uniform surface. The use of reclaimed sand in construction industry products further reduces the need for virgin natural sand.

[0048] It will be obvious to those skilled in the art that as technology advances, the concept of the present invention can be realized in various forms. The present invention and its embodiments are not limited to the examples described above, but can be modified as appropriate within the scope of the claims.

Claims

1. 1. An apparatus for reclaiming waste sand containing bentonite binder, comprising: a rotatable furnace having a first end and a second end, the furnace having at least one inlet at the first end for feeding the waste sand into the furnace and at least one outlet at the second end for discharging the heat-treated waste sand from the furnace; a burner disposed at the first end of the furnace capable of heating the waste sand fed into the furnace to thermally treat the waste sand so as to burn carbon from the bentonite binder and evaporate absorbed moisture; At least one lifter configured to capture at least a portion of the waste sand fed into the furnace so as to move along with the furnace on an inner periphery of the furnace until the waste sand falls toward a bottom of the furnace, the at least one lifter configured to guide the movement of the waste sand within the furnace toward the second end of the furnace and the at least one outlet at the second end of the furnace; a rotatable drum having a first end and a second end, the drum having at least one inlet at the first end for receiving the heat-treated waste sand into the drum and at least one outlet at the second end for discharging sand separated from the bentonite binder from the drum; at least one section for subjecting the heat-treated waste sand to mechanical processing to separate sand from the bentonite binder; at least one exhaust device at the first end of the drum for creating a flow of unheated air in a direction from the second end of the drum toward the first end of the drum to cool the sand separated from the bentonite binder; An apparatus comprising:

2. The at least one section for subjecting the heat-treated waste sand to mechanical processing is a crushing section for crushing the heat-treated waste sand.

2. The device of claim 1 .

3. At the first end of the drum, the at least one section is provided for subjecting the heat-treated waste sand to mechanical processing so as to separate the sand from the bentonite binder.

2. The device of claim 1 .

4. the furnace comprises at least one section at the second end for subjecting the heat-treated waste sand to the mechanical treatment to mechanically separate the sand from the bentonite binder; 2. The device of claim 1 .

5. the at least one exhaust device is configured to remove fines from the sand separated from the bentonite binder in the unheated air stream; 2. The device of claim 1 .

6. the at least one section for subjecting the heat-treated waste sand to mechanical processing is a grinding section having grinding balls that impact the waste sand to separate the sand from the bentonite binder; 2. The device of claim 1 .

7. the second end of the drum comprises at least one classifier for classifying the sand separated from the bentonite binder into at least one pass fraction and at least one fail fraction; the at least one acceptable fraction is discharged from the drum through the at least one outlet of the drum; 2. The device of claim 1 .

8. the drum includes at least one magnetic separator for separating magnetic particles from the sand separated from the bentonite binder; 2. The device of claim 1 .

9. The drum is disposed below the furnace and is disposed substantially parallel to the furnace in a horizontal direction.

2. The device of claim 1 .

10. 1. A method for reclaiming waste sand containing bentonite binder, comprising: subjecting the waste sand to a heat treatment to remove carbon and absorbed moisture from the bentonite binder in the waste sand; subjecting the heat-treated waste sand to a mechanical treatment to mechanically separate the sand from the bentonite binder; providing a cooling effect to the sand separated from the bentonite binder; The method is performed by the apparatus of claim 1 .

11. In the step of subjecting the waste sand to heat treatment, the waste sand is heated so as to burn carbon and evaporate absorbed moisture from the bentonite binder.

11. The method of claim 10.

12. The step of subjecting the heat-treated waste sand to the mechanical treatment includes at least pulverizing the waste sand.

11. The method of claim 10.

13. the step of providing a cooling effect to the sand separated from the bentonite binder comprises directing a stream of unheated air at the sand; 11. The method of claim 10.

14. Use of the sand regenerated by the method according to claim 10 in construction industry products, foundry sand, or power plant boiler sand.

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