JP2004041894A - Method of recovering magnesium from waste having coating material stuck thereto - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of recovering magnesium from waste having coating material stuck thereto which can reduce the treatment cost, enhances the added value of a recovered valuable material and improves economical efficiency. <P>SOLUTION: The method of recovering magnesium from waste having coating material stuck thereto includes a crushing process of crushing the magnesium-containing waste having coating material stuck thereto by using a first shear crusher 12, a magnetically attracted material removal process of removing the magnetically attracted material by using a magnetic separator 13 and a separation process of stripping the coating material stuck to the magnetically unattracted material by using a second shear crusher 16 from the magnetically unattracted material after the magnetically attracted material is removed in the magnetically attracted material removal process and, further, separating the stripped coating material by using either one of wind power separation, water washing or density separation, and, the valuable material comprising either one or both of the recovered magnesium and magnesium alloy is recycled. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for recovering and recycling valuable materials composed of magnesium and magnesium alloy from which paint has been removed from paint-containing magnesium-containing waste used for casings of mobile phones, casings of personal computers, and the like. It relates to a method for recovering magnesium.
[0002]
[Prior art]
In recent years, the need for lightweight materials has increased, and magnesium materials have been widely used as materials for, for example, automobiles and portable home appliances. For this reason, a lot of magnesium-containing waste to which paint has adhered has been generated from the process of manufacturing this product and from the city as used waste. In addition, this magnesium-containing waste is used only as a raw material for dissolving a recycled ingot because a paint that becomes an impurity at the time of regeneration adheres to magnesium.
Therefore, in order to expand the use of the magnesium-containing waste during recycling, a method of melting and reusing the magnesium-containing waste has been used. In this method, for example, the coating is peeled off by performing a wet chemical treatment or abrasive cleaning before melting the magnesium-containing waste, or the magnesium-containing waste is heat-treated in an inert atmosphere to remove volatile components. I have.
[0003]
[Problems to be solved by the invention]
However, the above-mentioned method of recovering magnesium from paint-attached waste has the following problems.
The method of stripping the coating by performing wet chemical treatment or blasting of abrasive material is expensive and not economical.
In addition, the method of removing volatile components by heat treatment is not economical because refining costs for removing metal oxide paint components mixed during melting are not economical, and there is a possibility that harmful gases are generated during volatilization and environmental pollution is caused. There is.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for recovering magnesium from paint-adhered waste, which can reduce the processing cost, increase the added value of the recovered valuable resources, and improve the economic efficiency. And
[0004]
[Means for Solving the Problems]
In the method for recovering magnesium from paint-attached waste according to the present invention according to the present invention, the magnesium-containing waste to which paint is attached is crushed using a first shear crusher, and crushed in a crushing step. A magnetically-separated material is removed from the crushed material using a magnetic force separator. Separating the paint adhered to the kimono, and further separating the paint peeled using any one of wind sorting, water washing, and specific gravity sorting, one of the recovered magnesium and magnesium alloy Or recycle valuable resources consisting of both. Here, the recovered magnesium alloy includes a Mg-Al system, a Mg-Zn system, and a Mg-Al-Zn system. As described above, in the separation step, the paint is peeled from the non-magnetically adhering matter contained in the magnesium-containing waste by using the second shear crusher. The coating material is peeled off and separated from the non-magnetically adhered material without performing the above, and a valuable material composed of one or both of magnesium and a magnesium alloy can be recovered.
Here, in the method for recovering magnesium from paint-attached waste according to the present invention, the non-magnetically attached matter is subjected to a heating treatment using a warming machine before the separation step, and the peelability of the paint attached to the non-magnetically attached matter is evaluated. Preferably, it is improved. In this way, by heating the non-magnetically attached material, the removability of the paint adhered to the non-magnetically attached material can be improved, so that the quality of the recovered valuable material can be improved.
[0005]
In the method for recovering magnesium from paint-attached waste according to the present invention, it is preferable to use warm air as a heating medium of a heating machine. Thus, the surface of the non-magnetically adhered material that has been heated by the heating machine can be kept in a dry state, so that when the dry process is performed in a subsequent step, the non-magnetically adhered material can be treated as it is.
In the method for recovering magnesium from paint-attached waste according to the present invention, the temperature of the warm air is preferably 50 to 250 ° C. Thereby, for example, the paint can be embrittled without burning.
In the method for recovering magnesium from paint-attached waste according to the present invention, it is preferable to use hot water as a heating medium of a heater. As a result, the removability of the paint adhered to the non-magnetic material can be further improved.
[0006]
In the method for recovering magnesium from paint-attached waste according to the present invention, the interval between adjacent blades during operation of the second shear crusher is set to 0.5 to 2 times the thickness of the non-magnetically adhered material. Is preferred. As described above, by setting the interval between the adjacent blades, it is possible to easily grasp the conditions under which the paint can be peeled off from the non-magnetic material.
In the method for recovering magnesium from paint-attached waste according to the present invention, the atmosphere in the second shear crusher is preferably one or both of a nitrogen gas and an inert gas. Thereby, in the state where oxygen is hardly present in the second shear crusher, it is possible to perform the treatment of the non-magnetized material having the valuable material composed of one or both of magnesium and the magnesium alloy. And explosion can be prevented.
In the method for recovering magnesium from paint-attached waste according to the present invention, it is preferable to continuously supply and discharge air at normal temperature into the second shear crusher. Thereby, it is possible to prevent in advance the temperature rise in the second shear crusher that occurs when processing the non-magnetically adhered material having a valuable material comprising one or both of magnesium and a magnesium alloy using the second shear crusher. Therefore, ignition and explosion of valuables can be prevented.
[0007]
In the method for recovering magnesium from paint adhering waste according to the present invention, it is preferable that the second shear crusher is provided with a dust collector. This makes it possible to easily remove the paint peeled off from the non-magnetized material by the second shear crusher from a valuable material composed of one or both of magnesium and a magnesium alloy.
In the method for recovering magnesium from paint-attached waste according to the present invention, it is preferable to classify the recovered valuables into coarse particles and fine particles using a classifier. Thereby, the collected valuables can be separated for each particle size.
In the method for recovering magnesium from paint-attached waste according to the present invention, among the recovered valuable resources, those having a particle size of 0.1 to 2 mm are preferably used as desulfurizing agents for steelmaking. As a result, the recovered valuable material can be used not only as a melting raw material for a regenerated ingot as in the related art but also as a desulfurizing agent for steelmaking.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.
Here, FIG. 1 is an explanatory view showing a flow of a method for recovering magnesium from paint adhering waste according to one embodiment of the present invention, and FIG. 2 is a partial cross section of a second shear crusher used in the method for recovering magnesium. FIG. 3 is a cross-sectional view taken along the line AA of FIG.
[0009]
As shown in FIG. 1, the method for recovering magnesium from paint-attached waste according to one embodiment of the present invention occurs, for example, in a process of manufacturing a product such as a material for an automobile or a material for a portable home appliance, Further, magnesium and magnesium alloys (for example, Mg-Al, Mg-Zn, and Mg-Al) may be used from a magnesium-containing waste (hereinafter, also simply referred to as a magnesium-containing waste) to which a paint generated as used waste from the city is attached. -Zn-based or the like), and recovers and recycles valuable resources composed of one or both of them. The details will be described below.
[0010]
A paint having a thickness of, for example, 0.1 to 100 μm is attached to the magnesium-containing waste. This paint is formed on the surface of a product by, for example, electroplating, chemical plating, hot-dip plating, thermal spray plating, vapor deposition plating, vapor phase plating, and the like, and is used for improving the protection and color of the product.
First, the collected magnesium-containing waste is supplied into the heater 11 by a predetermined amount using the continuous ore feeder 10, and is heated.
The heating device 11 is a device having a volume capable of charging magnesium-containing waste therein, and is a batch processing method. Warm air is used as a heating medium of the heater 11, the temperature is set to 50 to 250 ° C., and the magnesium-containing waste is heated for, for example, 30 minutes to 1 hour.
[0011]
Here, when the temperature of the warm air is lower than 50 ° C., the temperature is not sufficient to embrittle the paint and to improve the removability of the paint attached to the magnesium-containing waste. On the other hand, when the temperature of the hot air exceeds 250 ° C., depending on the type of the paint, the paint burns or decomposes, which may generate harmful gases. Therefore, if this harmful gas is released into the atmosphere, it causes air pollution. Here, a harmful gas recovery device can be installed, but the installation of the device is costly and not economical.
Therefore, in order to embrittle the paint and improve the releasability, and to suppress the burning and decomposition of the paint, it is preferable to set the temperature of the hot air to 50 to 150 ° C, more preferably 50 to 100 ° C. .
[0012]
In addition, as the heater, for example, a conveyor is disposed in a furnace having a cylindrical shape, and an apparatus in which the atmospheric temperature in the furnace is set to the above-described temperature is used. It is also possible to heat the magnesium-containing waste continuously transported by heating.
Hot water (hot water) obtained by heating water can also be used as the heating medium of the heating device. In this case, a container-shaped heater is used as the heater, and hot water heated to, for example, 50 to 100 ° C. is charged into the container, and a predetermined amount of magnesium-containing waste is poured into the hot water. I do.
As described above, since the non-magnetic material having valuable resources contained in the magnesium-containing waste is heated using the heating device 11, the removability of the paint attached to the non-magnetic material can be improved. it can.
[0013]
Next, the heated magnesium-containing waste is crushed to, for example, 50 mm or less using the first shear crusher 12.
As the first shear crusher 12, a conventionally known uniaxial shear crusher or a biaxial shear crusher can be used. A uniaxial shear crusher is a rotary blade provided with a blade around one rotary shaft, and a fixed blade provided at a predetermined interval around a rotary blade rotating around the rotary shaft. It is a device having. Here, by rotating the rotary blade and charging the magnesium-containing waste between the rotary blade and the fixed blade, the magnesium-containing waste is cut and crushed to the size described above. Further, the biaxial shear crusher is one in which a pair of rotary blades having blades provided around a rotary shaft are arranged at predetermined intervals. Here, the pair of rotary blades are rotated in the opposite directions about the respective rotary shafts, and the magnesium-containing waste is cut between the pair of rotary blades. Crushed.
Thereby, the magnesium-containing waste to which the paint has adhered can be processed into a crushed material having a size of 50 mm or less (the above, the crushing step).
[0014]
Subsequently, iron (magnetically attached matter) contained as a foreign substance is removed from the crushed material crushed in the crushing step by using a conventionally known magnetic force separator 13 (the above, the magnetically attached matter removing step).
Then, as shown in FIG. 2, the non-magnetized material after the magnetized material is removed in the magnetized material removing step is stored in a hopper 14 for temporary storage, and a predetermined amount is supplied to the second shearing machine 15 by a fixed amount feeder 15. It is supplied into the crusher 16. Here, the paint adhered to the non-magnetic material is peeled off using the second shear crusher 16, and the non-magnetic material is crushed to a size of, for example, 5 mm or less.
In addition, the hopper 14 and the fixed-quantity feeder 15 are integrally provided above the second shear crusher 16 from the upstream side to the downstream side. The hopper 14 has, for example, an inclined portion 17 having an angle θ of 30 degrees, and the quantitative feeder 15 has a partition portion (not shown) that can open and close the non-magnetized material supply port 18 of the second shear crusher 16. )have.
Thereby, the non-magnetic material moving downward along the inclined portion 17 can be supplied by the partitioning portion at a fixed amount via the non-magnetic material supply port 18 of the second shear crusher 16.
Here, the hopper and the fixed-quantity feeder can be separately provided without being provided integrally with the second shear crusher 16.
[0015]
As shown in FIGS. 2 and 3, a motor 19 is provided below the second shear crusher 16, and the axis of the rotation shaft 20 of the motor 19 is higher than the height of the second shear crusher 16. Are arranged in the same direction. The rotating shaft 20 is rotatably provided on the fixed plate 21 via a bearing 22 so as to protrude from a fixed plate 21 provided above the motor 19.
A fixed portion 23 of the rotating shaft 20 that protrudes above the fixed plate 21 is integrally provided with a square shape in plan view. At each corner (four places) of the fixed part 23, there are provided rotary blades 24 vertically arranged from the lower end to the upper end of the fixed part 23. Each rotary blade 24 is arranged so that the distance from the cutting edge of the rotary blade 24 to the axis of the rotary shaft 20 is substantially constant, and the arrangement position is provided so as to be movable. The cutting edge shape of the rotary blade 24 may be either an acute angled shape or a rounded shape, but the rounded blade has better removability of the paint adhering to the non-magnetic material. It is.
Thereby, the cutting edge of each rotary blade 24 is located on the same circumference around the axis of the rotary shaft 20.
[0016]
A plurality of fixed blades 25 (six in this embodiment) are provided in the periphery of the rotary blade 24 in a vertical arrangement, and the interval between adjacent blades when the second shear crusher 16 is operated, that is, The distance d between the cutting edge of the rotary blade 24 and the fixed blade 25 is set to 0.5 to 2 times the thickness of the non-magnetically attached material.
Here, when the distance d between the blades of the rotary blade 24 and the fixed blade 25 is less than 0.5 times the thickness of the non-magnetically adhered material, the distance d between the blades becomes narrower, so that the paint is peeled from the non-magnetically adhered material. Before the crushing process of the non-magnetically attached material is completed, the quality of the recovered valuable material is reduced. On the other hand, if the distance d between the rotary blade 24 and the fixed blade 25 is more than twice the thickness of the non-magnetic material, the distance d between the cutting edges is widened. It is difficult to enter the gap between the non-magnetic material and the fixed blade 25, and the time required for removing the paint from the non-magnetically attached material becomes longer, which is not economical.
Therefore, in order to improve the quality of the collected valuable resources and perform the stripping operation economically, the distance d between the cutting edge of the rotary blade 24 and the fixed blade 25 during the operation of the second shear crusher 16 is set to a non-magnetic value. It is preferably set to 0.8 to 1.7 times, more preferably 1 to 1.5 times the thickness of the kimono.
[0017]
On the downstream side of the second shear crusher 16, a mesh screen 26 for connecting a part of the plurality of fixed blades 25 is arranged in an arc shape along the rotation position of the rotary blade 24. The size of the mesh of the screen 26 is set to, for example, 1 to 5 mm in accordance with the size of valuable resources to be collected.
On the downstream side of the screen 26, there is provided a discharge unit 27 for discharging valuables that have passed through the mesh of the screen 26. Above the discharge unit 27, a duct 28 is provided. On the downstream side of the duct 28, a dust collector 29 is provided, and by operating the dust collector 29, the paint can be collected from the mixture of the paint and the non-magnetized material from which the paint discharged through the screen 26 has been removed. . The non-magnetic material from which the paint has been removed is discharged as a valuable material from a discharge port 30 provided below the discharge unit 27.
Further, since the wheels 31 as an example of the moving means are provided below the second shear crusher 16, the second shear crusher 16 can be easily moved.
[0018]
By supplying one or both of a nitrogen gas and an inert gas (for example, an argon gas or a helium gas) into the second shear crusher 16, the atmosphere in the second shear crusher 16 is supplied. In the absence of oxygen to prevent ignition and explosion of valuables during the work of peeling paint from non-magnetized material. Here, since the dust collector 29 is used for separating the peeled paint, it is preferable that the above-described gas be continuously supplied so that the pressure in the second shear crusher 16 does not become negative.
As described above, by using the dust collector 29 having the capability of wind separation, the peeled paint can be easily separated from the valuable material (the above, the separation step).
[0019]
In addition, since the non-magnetically-adhered matter treated in this separation step is subjected to the heating treatment using the heater 11 before the separation step, the removability of the paint adhered to the non-magnetically-adhered matter is improved. Thereby, the paint can be easily separated from the non-magnetically adhered material by using the second shear crusher 16, so that the quality of the recovered valuable material can be improved.
The second shear crusher is provided with an air supply port and an air discharge port, and continuously supplies air at room temperature (for example, 10 to 25 ° C.) from the air supply port to the air discharge port. By discharging, it is also possible to prevent a temperature rise in the second shear crusher.
[0020]
The valuable resources recovered from the outlet 30 of the second shear crusher 16 are further classified into coarse particles (for example, more than 2 mm and 5 mm or less) and fine particles (for example, 0.1 mm) by using a classifier 32 (a screen, a sieve, or the like). (2 mm or less).
Of the classified valuables, those having a particle size of 0.1 to 2 mm are used as desulfurizing agents for steelmaking.
As a result, the recovered valuable resources can be recycled not only as a melted raw material for recycled ingots but also as a desulfurizing agent for steelmaking, as in the related art, so that the use of valuable resources can be expanded.
[0021]
As described above, the present invention has been described with reference to one embodiment. However, the present invention is not limited to the configuration described in the above-described embodiment, and is described in the claims. Other embodiments and modifications that can be considered within the scope of the present invention are also included. For example, the present invention is also applied to a case where the method for recovering magnesium from paint-attached waste of the present invention is configured by combining some or all of the above-described embodiments and modified examples.
In the above-described embodiment, the case where the paint-containing magnesium-containing material before being charged into the first shear crusher is heated in advance using a warmer has been described. However, when the removability of the paint is good, it is of course possible to directly supply the magnesium content containing paint from the continuous feeder to the first shear crusher without heating the content with the heater. .
[0022]
Further, in the above embodiment, the magnesium-containing waste having non-magnetized matter is heated using a warming machine before the crushing step before the separation step, and the paint adhered to the non-magnetized matter. The case where the releasability of the resin was improved was described. However, before the separation step, it is also possible to heat only the non-magnetically attached substance using a heating machine after the magnetically attached substance removing step. In this case, the amount of processing by the heating device can be reduced, and the processing time can be shortened, so that it is economical and the workability is improved.
In the above-described embodiment, a case has been described in which a dust collector having an ability of wind separation is used to separate the paint separated in the separation step. However, as a method of separating the peeled paint, other wind separators having the ability of the wind separator, for example, a wind separator that uses a conventionally known specific gravity difference and the shape of the separation target, and water washing, or specific gravity sorting It is also possible to use a conventionally known wet-type or dry-type specific gravity separator having the above-mentioned ability. Here, when a water-washing or wet-type specific gravity separator is used, dirt attached to the surface of the collected valuable resources can be washed. When a wind separator or a dry-type specific gravity separator is used, valuable resources recovered as they are without drying in a subsequent process can be used.
[0023]
【The invention's effect】
In the method for recovering magnesium from paint-attached waste according to any one of claims 1 to 11, in the separation step, the paint is peeled from the non-magnetically adhering matter contained in the magnesium-containing waste by using a second shear crusher. As described above, the coating material can be peeled off and separated from the non-magnetically adhered material without performing a wet chemical treatment, a polishing material projection, or a heat treatment, and a valuable material composed of one or both of magnesium and a magnesium alloy can be recovered. Therefore, at the time of processing valuable resources, the cost can be reduced, the added value of the recovered magnesium can be increased, the economy can be improved, and there is no possibility of causing environmental pollution.
In particular, in the method for recovering magnesium from paint-attached waste according to claim 2, since the non-magnetically adhered material is heated, the removability of the paint attached to the non-magnetically adhered material can be improved. Quality can be improved. Therefore, the use of valuable resources can be broadened more than before.
[0024]
In the method for recovering magnesium from paint-attached waste according to the third aspect, the surface of the heated nonmagnetic material can be kept dry by using warm air as the heating medium. In the case of performing the dry treatment, the non-magnetically attached material can be treated as it is. This eliminates the need for the step of drying the non-magnetized material, thereby improving workability during processing.
In the method for recovering magnesium from paint-attached waste according to the fourth aspect, the paint can be embrittled without burning, so that valuable resources can be collected without generating harmful gas.
In the method for recovering magnesium from paint-attached waste according to the fifth aspect, since hot water is used as the heating medium, the removability of the paint attached to the non-magnetically adhered material can be further improved. In addition, at this time, since the dirt and the like attached to the surface of the non-magnetically attached material can be removed by the hot water, the purity of the recovered valuable material can be further increased, and the use of the valuable material can be further expanded.
[0025]
In the method for recovering magnesium from paint-attached waste according to the sixth aspect, by setting the interval between adjacent blades, it is possible to easily grasp the conditions under which the paint can be peeled off from the non-magnetically adhered material. This eliminates the need to select appropriate conditions for peeling the paint each time the work is performed, thereby improving workability.
In the method for recovering magnesium from paint-attached waste according to claim 7, in the second shear crusher, in the state where almost no oxygen is present, a non-magnetic material having a valuable material comprising one or both of magnesium and a magnesium alloy is provided. Since the kimono can be processed, ignition and explosion of valuables can be prevented. Therefore, the work of peeling the paint from valuable resources can be performed safely.
In the method for recovering magnesium from paint-attached waste according to claim 8, the second shear crusher is used to process a non-magnetically adhered material having a valuable material comprising one or both of magnesium and a magnesium alloy. The resulting temperature increase in the second shear crusher can be prevented in advance by the normal temperature air, so that ignition and explosion of valuables can be prevented. Therefore, the work of peeling the paint from valuable resources can be performed safely. In addition, since air can be used to prevent a rise in temperature, the processing can be performed with almost no running cost, which is economical.
[0026]
In the method for recovering magnesium from paint-attached waste according to claim 9, the paint separated from the non-magnetically adhered substance by the dust collector by the second shear crusher is a valuable material comprising one or both of magnesium and a magnesium alloy. Since it can be easily removed from the object, the workability is improved and the possibility of causing air pollution by dust can be reduced.
In the method for recovering magnesium from paint-attached waste according to the tenth aspect, the collected valuable resources can be separated for each particle size, so that valuable resources having a particle size according to the purpose of use can be easily selected. Workability is good.
In the method for recovering magnesium from paint-attached waste according to claim 11, the recovered valuable material can be used not only as a conventional melting material for a reclaimed ingot but also as a desulfurizing agent for steelmaking. . Therefore, the use of the recovered valuable resources can be expanded, and it is economical.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a flow of a method for recovering magnesium from paint-attached waste according to one embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of a second shear crusher used in the magnesium recovery method.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
[Explanation of symbols]
10: Continuous feeder, 11: Heater, 12: First shear crusher, 13: Magnetic separator, 14: Hopper, 15: Fixed feeder, 16: Second shear crusher, 17: Inclined part, 18: non-magnetic attachment supply port, 19: motor, 20: rotating shaft, 21: fixed plate, 22: bearing, 23: fixed part, 24: rotating blade, 25: fixed blade, 26: screen, 27: Discharge unit, 28: duct, 29: dust collector, 30: outlet, 31: wheels, 32: classifier

Claims (11)

A crushing step of crushing the magnesium-containing waste to which the paint has adhered using a first shear crusher;
From the crushed material crushed in the crushing step, a magnetically attached material removing step of removing the magnetically attached material using a magnetic force separator,
The paint adhered to the non-magnetic material is peeled off from the non-magnetic material after the magnetic material is removed in the magnetic material removing step by using a second shearing crusher, and further, wind separation, water washing, and specific gravity A separating step of separating the peeled paint by using any one of the sorts, and recycling the valuable material comprising one or both of the recovered magnesium and the magnesium alloy, wherein For recovering magnesium from coal. The method for recovering magnesium from paint-attached waste according to claim 1, wherein the non-magnetically adhered material is heated using a heating machine before the separation step, and the paint adhered to the non-magnetically adhered material is removed. A method for recovering magnesium from paint-attached waste, characterized in that the method improves magnesium. The method for recovering magnesium from paint-deposited waste according to claim 2, wherein warm air is used as a heating medium of the heater. The method for recovering magnesium from paint-attached waste according to claim 3, wherein the temperature of the hot air is 50 to 250C. The method for recovering magnesium from paint-deposited waste according to claim 2, wherein hot water is used as a heating medium of the heater. The method for recovering magnesium from paint-attached waste according to any one of claims 1 to 5, wherein an interval between adjacent blades at the time of operation of the second shear crusher is determined with respect to a thickness of the non-magnetized material. A method for recovering magnesium from paint-attached waste, wherein the method is set to 0.5 to 2 times. The method for recovering magnesium from paint-attached waste according to any one of claims 1 to 6, wherein the atmosphere in the second shear crusher is one or both of a nitrogen gas and an inert gas. A method for recovering magnesium from paint adhering waste, characterized by the following. The method for recovering magnesium from paint-attached waste according to any one of claims 1 to 6, wherein air at normal temperature is continuously supplied and discharged into the second shear crusher. For recovering magnesium from waste paint deposits. The method for recovering magnesium from paint-attached waste according to any one of claims 1 to 8, wherein the second shear crusher is provided with a dust collector. Magnesium recovery method. The method for recovering magnesium from paint-attached waste according to any one of claims 1 to 9, wherein the collected valuables are classified into coarse particles and fine particles using a classifier. How to recover magnesium from waste. The method for recovering magnesium from paint-attached waste according to any one of claims 1 to 10, wherein, among the recovered valuable resources, those having a particle size of 0.1 to 2 mm are used as a desulfurizing agent for steelmaking. A method for recovering magnesium from paint-attached waste, characterized in that:

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