JPWO2007099714A1 - Metal recovery processing method and high gradient magnetic separation apparatus - Google Patents

Abstract

This invention does not use complicated and high energy, which has been attempted from fine powders containing valuable metals derived from waste, and makes valuable metals magnetized, and recovers valuable metals using magnetic force, which is a simple separation method. The purpose is to do. To this end, the metal recovery treatment method of the present invention mixes and heats a fine powder containing a metal with an iron compound, magnetizes the powder of the iron compound containing the metal component, and separates the magnetized product and the non-magnetized product. Separated and recovered by magnetic force, valuable metals are recovered from this magnetized product.

Description

The present invention relates to a recovery process of a metal component contained in waste or the like.

There are two types of waste recycling: thermal recycling and material recycling, and thermal recycling is progressing from measures to reduce CO ₂ etc., but material recycling, especially valuable metal recovery, is being carried out in various ways. As described in Patent Document 1, a process using a complex process and using high energy (particularly thermal energy) is the main one. The following are typical conventional techniques for recovering valuable metals from fine powder containing valuable metals derived from waste.

Extraction separation is a method in which fine powder containing valuable metals derived from waste is put into a solvent whose pH is adjusted (strong acid, strong alkali) and separated using the difference in solubility of any metal in the solvent due to the difference in pH. is there. Distillation separation uses a boiling point and vapor pressure of an arbitrary metal at an arbitrary temperature by filling a certain container with fine powder containing valuable metals derived from waste and heating (in some cases, adding a reduced pressure). This is a method in which an arbitrary metal is vaporized under a (pressure) condition and then condensed and recovered by a condenser (condenser). Further, there is a method similar to a metal refining process, in which a fine powder containing valuable metals derived from waste is melted at a high temperature, and an arbitrary metal is recovered using a difference in melting point or the like of the arbitrary metal.
JP-A-9-263844

In the extraction and separation, the dissolved metal cannot be separated only by the difference in pH, and a high-concentration but other impurities are dissolved at the same time, resulting in a quality recovered product. In addition, since the solvent used for pH adjustment is a strong acid or strong alkali, the equipment configuration requires complicated handling and care, and waste disposal of the waste solvent is costly and environmentally intensive. Distillation separation is not suitable for metals that require high temperatures for vaporization (mainly precious metals), and impurities (low-boiling non-metals) contained in the waste also evaporate, so other impurities dissolve at the same time. And it will become a recovered product of the contained quality. This also has a complicated equipment configuration similar to the extraction and separation described above.

On the other hand, in a method of recovering a metal using a difference in melting point, etc., a high temperature is required for a metal having a high melting point (mainly noble metal), and the metals become intermetallic compounds (alloys). There is also a large-scale equipment (refining process) as the equipment configuration.

Valuable metal recovery is considered to be an indispensable item in the future waste recycling market, and in the present invention, the complicated and high energy that has been tried from the fine powder containing valuable metal derived from waste has not been used. The purpose is to collect valuable metals using magnetism, which is a simple separation method.

In order to solve the above object, the metal recovery processing method of the present invention is characterized in that a fine powder containing a metal is mixed with an iron compound and heated to magnetize the powder of the iron compound containing the metal component. And As the iron compound, for example, iron oxide can be used. Further, the magnetized product and the non-magnetized product may be separated by a magnetic force. The heating temperature is preferably lower than the melting point of the glass fiber.

In the present invention, it is possible to make the valuable metal magnetized by subjecting the fine powder after mixing and homogenization to a magnetizing treatment (heating treatment) at a lower temperature than in the prior art. It has the effect that the energy input to the can be reduced. The additive is also an inexpensive iron compound, which can reduce the total running cost. In the present invention, there are only three simple steps in which the device configuration is individual as compared with the prior art, and the device operation factor of each step is independent of other device operations, and is easy to perform. It can be implemented even if separated. Compared to the conventional technology, the overall safety of the process is also reduced from the point that it does not have a complicated equipment configuration, does not use high temperatures, is easy to handle additives, and is less environmentally friendly by preventing the elution of valuable metals in the recovered material. Be improved. In addition to increasing the cost value by concentrating valuable metals in the recovered magnetic material, and being magnetic and fine powder, the recovered magnetic material itself can be an alternative to intermediate or final industrial products.

It is a flowchart which shows the process of a metal collection | recovery processing method. It is an image which shows the external appearance of the mixed powder after a heating. It is a graph which shows the collection | recovery rate by the classification by magnetic force. It is a graph which shows the XRD pattern of the PCB-FeO mixed powder after a heating. It is the graph of the SEM image and EDX analysis of PCB-FeO mixed powder after a heating. It is a graph which shows the magnetic side distribution rate of Cu. It is a graph which shows the magnetic side distribution rate of Fe. It is a graph which shows the magnetic side distribution rate of Ni. It is a graph which shows the magnetic side distribution rate of Sn. It is a graph which shows the magnetic side distribution rate of Pb. It is a graph which shows the magnetic side distribution rate of the whole metal component. It is a graph which shows the result of a sample vibration type magnetization measurement. It is a graph which shows dispersion | distribution of (DELTA) (theta) -tan (theta). It is a graph of SEM image and EDX point analysis of PCB powder. It is a graph which shows the average collection | recovery rate of a magnetized material. It is a graph which shows the average distribution rate to the magnetic side of a metal component. It is a block diagram which shows the structure of a high gradient magnetic sorting apparatus.

Explanation of symbols

1. 1. High gradient magnetic fractionator 2. Sample input part 3. Air blower Matrix 5. 5. High gradient magnetic separation unit 6. Vibration unit Magnetized material recovery unit8. Non-magnetized material recovery unit

The best mode for carrying out the present invention will be described. The fine powder containing valuable metal derived from waste is mixed with an iron compound and heated in the atmosphere to magnetize the valuable metal, and the magnetized magnetic material and non-magnetic material are separated by magnetic separation. Iron compounds to be mixed with fine powder containing valuable metals derived from waste are FeO (divalent), Fe ₃ O ₄ (FeO · Fe ₂ O ₃ ; divalent, trivalent), Fe ₂ O ₃ (trivalent). And an inexpensive iron compound represented by Fe (OH) (trivalent).

The particle size of the iron compound to be mixed with the fine powder containing the valuable metal derived from the waste is determined by the fine powder containing the valuable metal derived from the waste that is the object to be mixed, and is preferably the same or smaller. In the method of separating magnetic material and non-magnetic material after magnetizing by magnetic separation, the mixing ratio of the iron compound mixed with the fine powder containing valuable metal derived from waste is the value derived from the waste that is the object to be mixed. It is preferable to determine the content of valuable metal to be recovered in the fine powder containing metal.

The heating temperature and time are determined by the type and content of the recovery target valuable metal contained in the fine powder containing the valuable metal derived from the waste, but are preferably lower than the melting point of the glass fiber, and in many cases up to about 800 ° C. Heating temperature and several minutes to several tens of minutes

The magnetic field strength for magnetic separation is preferably determined by the magnetic force of the obtained magnetic material. Magnetic separation can be performed in both dry and wet atmospheres. The most suitable type is the impurities other than valuable metals (mainly non-magnetic substances) contained in fine powder containing valuable metals derived from waste. The concentration is preferably determined according to the property of the concentration.

It is preferable that valuable metals in the recovered magnetic material and non-magnetic material are prevented from being eluted, and that there is safety against environmental loads.

The recovered magnetic material α-Fe ₂ O ₃ is highly stable against sunlight, air, water, and heat and has an ability to absorb ultraviolet rays. Therefore, abrasives, red pigments, cement colorants, paints, inks and tiles・ Used as a paint for brick materials. In addition, it has industrial uses as a raw material for ferrite cores, magnets, and magnetic recording materials.

FIG. 1 is a flowchart showing a metal recovery process. It has a mixture of fine powder and iron compound, magnetic treatment (heat treatment), and magnetic separation process.

The mixing of fine powder and iron compound will be described. In this step, the optimum iron compound powder is mixed and homogenized with the fine powder containing valuable metals derived from waste. Typical types of iron compounds are FeO (divalent), Fe ₃ O ₄ (FeO · Fe ₂ O ₃ ; divalent, trivalent), Fe ₂ O ₃ (trivalent) and Fe (OH) ( Trivalent). The particle size of the iron compound is determined by the fine powder containing valuable metal derived from waste, which is the object to be mixed, and is preferably the same particle size or less. The mixing ratio of the iron compound is determined by the content of the valuable metal to be recovered in the fine powder containing the valuable metal derived from the waste that is the object to be mixed.

Next, the magnetizing process (heating process) will be described. In this step, the iron compound mixed powder mixed and homogenized under the optimum conditions as described above is heated in the atmosphere. The heating temperature is determined by the type and content of the recovery target valuable metal contained in the fine powder containing the valuable metal derived from the waste, but a heating temperature up to about 800 ° C. is often required. Although the heating time is determined by the type and content of the recovery target valuable metal contained in the fine powder containing the valuable metal derived from the waste, it often requires several minutes to several tens of minutes of heating time.

The magnetic separation will be described. In this step, the iron compound mixed powder heat-treated under the optimum conditions in the above step is separated into a magnetic material and a non-magnetic material using magnetic force. The magnetic field strength is determined by the magnetic force of the magnetic material obtained by the reaction in the upper magnetizing process (heating process). As a separation method, magnetic separation is possible in either dry or wet atmosphere, but which is suitable depends on impurities other than valuable metals contained in fine powder containing valuable metals derived from waste (mainly non-magnetic substances). It is desirable to determine it according to the nature of the concentration.

Embodiments of the present invention will be described. Fine powder containing valuable metals waste caused is wasted PCBs (hereinafter PCB: P rint C ircuit B oard ) having the composition shown in Table 1 were used powder after removal of organic components from. In addition to Cu, Fe, Ni, Sn, and Pb as valuable metals, this powder contains Au, Ag, and Pd as noble metals. Further, the iron compound to be mixed becomes more stable as the oxidation number increases from 2 to FeO (divalent), Fe ₃ O ₄ (FeO · Fe ₂ O ₃ ; divalent, trivalent), Fe ₂ O ₃ (3 Valence) and Fe (OH) ₃ (trivalent) were used for comparison. All the iron compound powders used had a particle size of 250 μm or less. The iron compounds having magnetism were FeO and Fe ₃ O ₄ .

The mixing homogenization and heat treatment conditions are shown in Table 2. The powder subjected to the magnetic materialization treatment was subjected to magnetic separation, and the magnetic separation was performed by inserting a magnet into pure water containing the magnetic treatment powder and performing wet magnetic separation while stirring.

FIG. 2 is a photograph showing an example of the appearance of the powder after the magnetic materialization treatment. The appearance of the PCB-iron oxide mixed powder changed from gray to reddish brown as the oxidation number of the mixed iron compound increased from 2 to 3 when treated with 1073K, especially in the Fe (OH) ₃ mixed powder It had a bright red color. In addition, the mixed powder after the 1073K treatment progressed as the valence decreased, and in the FeO mixed powder, the sintering proceeded under all conditions. The powder in which Fe ₃ O ₄ was mixed was smaller than the FeO mixed powder at 1073K, but sintering proceeded. The Fe ₂ O ₃ and Fe (OH) ₃ mixed powder having a valence of 3 was powdery. Further, the mixed powder subjected to the 1273K treatment was sintered under all conditions.

In the mixed powder of FeO and Fe ₃ O _4, all the masses produced by the 1073K treatment were easily broken. However, the sintered body produced in the 1273K process was sintered and accompanied by grain bonding. Glass fiber, which is the main component of PCB powder, has a softening point of 1123K in an active atmosphere. Therefore, since the mixed powder was a glass fiber of PCB powder, the fiber shape could not be maintained exceeding 1123K, and sintering proceeded at 1273K. Further, as a result of the heat treatment of the iron compound used in this example alone at 873 K, only FeO was sintered and further exhibited magnetism.

When the magnetic separation was performed, the 1073K treated powder, which was easily broken when wet-stirred, was used as it was, and the 1273K treated powder was a strong sintered body and was used after pulverization. As shown in FIG. 3 (a), the magnetic substance ratio of the FeO mixed powder tended to increase as the heating time was shorter at a mixing ratio of 6: 4, and was 93.83% at 10 min. The ratio of the magnetic substance in the FeO mixed powder was the same as the mixing ratio of 6: 4 when the mixing ratio was 5: 5, and the highest ratio was 92.38% in 10 minutes. In the FeO mixed powder, the ratio of magnetic substances did not increase even when the heating time was lengthened. Therefore, it is considered that the oxidation reaction was completed in 10 minutes. Next, as a result of performing a treatment for 10 min at a heating temperature of 1273 K, the magnetic substance ratio was 93.60%, and there was no effect due to an increase in the heating temperature at 1073 K or more.

As shown in FIG. 3B, the Fe ₃ O ₄ mixed powder had the highest magnetic substance ratio at 86.01% under the 6: 4 mixing ratio and 10 min treatment conditions. The ratio of magnetic substances decreased to 82.67% when the heating temperature was increased to 1273K, and there was no effect due to the increase in heating temperature at 1073K or more, as with the FeO mixed powder.

As shown in Fig. 3 (c), the Fe ₂ O ₃ mixed powder had almost no difference in the magnetic material ratio due to the difference in the mixing ratio at the heating time of 10 min, but the magnetic material ratio was increased by increasing the heating temperature and extending the heating time. Showed a tendency to increase. The highest magnetic substance ratio was 80.58% under the conditions of a mixing ratio of 6: 4, a heating temperature of 1073 K, and a heating time of 60 minutes. In addition, the magnetic material ratio at the same 6: 4 mixing ratio and heating time of 10 min was 52.58% at 1073K, whereas it was 70.10% at 1273K, and the effect of increasing the temperature on the magnetic material was recognized.

As shown in Fig. 3 (d), the Fe (OH) ₃ mixed powder tended to increase in the magnetic substance ratio as the heating temperature increased, but the maximum values were 6: 4, 1273K, 10min. It was 86.32%. The amount of magnetic material produced tends to decrease as the valence of the iron compound to be mixed increases from divalent. When Fe ₃ O ₄ containing divalent FeO and FeO is mixed, the amount of magnetic compound produced is short at a low heating temperature. The reaction was completed by the treatment. On the other hand, since Fe ₂ O ₃ and Fe (OH) ₃ are the most stable compounds with an oxidation number of Fe of 3, it is considered that a long heating time is required at a high temperature in order to have magnetism.

From the obtained results, the most magnetic powder produced by mixing with PCB powder was FeO powder. In addition, the appearance after the magnetic separation was stronger in the reddish brown of the magnetic material and the gray of the nonmagnetic material than before the magnetic separation. Therefore, it is expected that the magnetic material is a metal component mainly composed of iron oxide, and the non-magnetic material is mainly composed of glass fibers in the PCB powder.

The X-ray diffraction of the mixed powder transferred to the magnetic side in the magnetic separation is, as shown in FIG. 4, which is an FeO-added mixed powder as an example, although there is a difference in strength depending on the mixed iron compound, but all hematite (α The peak of -Fe ₂ O ₃ ) was predominant. Hematite has a hexagonal structure, is a non-magnetic iron oxide, has no magnetism, and no peaks of magnetite (Fe ₃ O ₄ ) and maghemite (γ-Fe ₂ O ₃ ) are spinel structures. It was. Further, in the powder transferred to the nonmagnetic side, the hematite peak was detected as the oxidation number of the mixed iron compound increased from 2 to 3, as shown in FIG. In the FeO mixed powder, the powder that moved to the nonmagnetic side showed a large SiO ₂ peak and was mainly composed of glass fiber. In addition, a large amount of amorphous broad was detected in the non-magnetic powder of the mixed powder excluding Fe ₂ O ₃ .

The SEM / EDX observation of the mixed powder after the magnetic separation was, as an example, FeO-added mixed powder, as shown in FIG. From the EDX analysis results, it became clear that the magnetic powder that was hematite in the previous section incorporated the metal components contained in the PCB powder. Ni and noble metal components had low concentrations and small particle sizes, and no clear distribution was observed. In addition, the peak of Au detected by the EDX graph is Au used for vapor deposition.

The magnetic side and nonmagnetic side distribution ratio of the metal component in the PCB powder was calculated from the weight of the powder recovered by magnetic separation and the EDX plane analysis result, and is shown in FIGS.
As shown in FIG. 6, the distribution ratio of Cu to the magnetic side showed the highest value in the FeO mixed powder, which was 95.73% at 1073K and 95.06% at 1273K under the conditions of 6: 4 and 10 min.
As shown in FIG. 7, the magnetic side distribution ratio of Fe showed a high distribution ratio of 90% or more in all heating conditions in the powder in which FeO and Fe ₃ O ₄ were mixed at a ratio of 6: 4. In particular, the powder mixed with FeO showed a distribution ratio of 97% or more under the heating condition of 6: 4, and the result was that Fe could be recovered as a magnetic substance at a very high ratio.
As shown in FIG. 8, the maximum magnetic side distribution of Ni is 86.12% for Fe ₂ O ₃ except for 100%, 96.37% for FeO, 94.03% for Fe ₃ O ₄ and 89.27% for Fe (OH) _3. there were. Ni has a very low content of 0.05 mass% in the PCB powder, so the reliability of the analysis results is considered to be low. However, since Ni was present in the PCB in the form of Fe—Ni, it is considered that the distribution ratio of Fe greatly affects the distribution ratio of Ni.
As shown in FIG. 9, the magnetic side distribution ratio of Sn was 90% or more in a mixing ratio of 6: 4 in FeO, Fe ₃ O ₄ and Fe (OH) ₃ . Since Sn is present in the PCB in the form of Cu-Sn, it is considered that it moves to the magnetic side in proportion to the magnetic materialization of Cu.
As shown in FIG. 10, the Pb magnetic side distribution ratio was 92.61% at 6: 4 and 93.23% at 5: 5, and only 90% or more.
As shown in FIG. 11, the magnetic side distribution ratio of the entire metal component showed 90% or more at 6: 4 for all FeO 6: 4 and 5: 5 for 1273 K, 10 min, and 6: 4 for Fe ₃ O ₄ . The magnetic side distribution ratio of the metal component tended to decrease as the oxidation number of the mixed iron compound approached 3, similar to the above-described magnetic substance ratio.
In the data on the magnetic side distribution ratio shown in FIGS. 6 to 11, the effects above a certain level have been confirmed, and the present invention can be widely applied including the range of the mixing ratio not specifically shown here. It is.
Among them, FeO, in particular, distributes the metal component to the magnetic side at a high rate of 90% or more by mixing with PCB. From the result of magnetic separation, it is optimal for mixing with PCB powder.

The Fe ₂ O ₃ standard reagent powder and the mixed powder transferred to the magnetic side by magnetic separation were subjected to magnetization measurement using a sample vibration type magnetometer (VSM). As shown in FIG. 12 (a), standard Fe ₂ O ₃ had a saturation magnetization of 0.61 emu / g and showed almost no magnetism. However, as shown in FIG. 12 (b), the Fe ₂ O ₃ powder obtained in this example shows a saturation magnetization of 7.54 emu / g, and remanence and coercive force are as small as 1.01 emu / g and 0.19 KOe. However, although it has the same structure as hematite, which does not normally have magnetism, it showed the characteristics of a magnetic material.

The reason why the hematite powder obtained in this example has magnetism was examined in detail by paying attention to the distortion of the crystal lattice from the X-ray diffraction results shown in FIG. Bragg's diffraction conditional expression is given by the following expression.
2d · sin θ = nλ (Formula 1)
When the above equation is fully differentiated, Δd · sin θ + d · cos θ · Δθ = 0
Δd / d = −Δθ / tanθ (Formula 2)
The change in the lattice spacing, that is, the lattice distortion Δd / d is obtained from the gradient of the change amount Δθ / tan θ of the diffraction angle θ. From Equation 2, the sensitivity of the lattice strain increases as the value of tan θ, that is, the diffraction angle θ increases. Therefore, the standard hematite produced a scatter diagram of Δθ-tanθ in comparison with the X-ray diffraction result of the magnetic hematite powder obtained in this example.
Δθ of the (0 1 2) and (0 2 4) planes not involving the a-axis was constant at 0.0185 as shown in FIG. On the other hand, the inclination in the plane where the a axis is involved is -0.04405 from (1 0 4) → (2 0 8), -0.04977 from (1 1 0) → (2 2 0), (1 1 3) → (2 2 6) was -0.03154, indicating a negative slope. Therefore, from the equation, Δd / d shows a positive gradient in the plane where the a-axis is involved, and the a-axis is extended.
Therefore, the produced Fe ₂ O ₃ uses the d, h, k, and l values measured by X-ray diffraction from the Miller index and the interplanar formula, and the c value is the c value of the standard Fe ₂ O ₃ shown in Table 3. The a value was calculated assuming the same 13.74890cm. The formulas for Miller index and interplanar spacing in hexagonal crystals are given by
1 / d ² = (3/4) {(h ² + hk + k ² ) / a ² } + l ² / c ² (Formula 3)

The a value of the prepared Fe ₂ O ₃ calculated from Equation 3 was 5.04944%, which was found to be larger than the a value of standard Fe ₂ O ₃ shown in Table 3. Here, the atomic radius of the metal element to be measured in this example, Fe is 1.24%, while Cu is 1.28%, Ni is 1.25%, Sn is 1.41 and 1.51%, and Pb is 1.76. It is a spear. Also, the noble metal elements are 1.44% Ag, 1.44% Au, 1.37% Pd, and all the metal elements contained in the PCB powder have a larger atomic radius than Fe, and these metal elements are solid in the hematite. It is thought that it is melted.

The magnetic hematite powder obtained in this example was enlarged 2,000 times using SEM / EDX, and the simultaneous peaks of Fe, Cu and Sn were detected from the point analysis results at the positions of the + marks shown in FIG. . Therefore, Cu and Sn elements were dissolved in the magnetic hematite powder.

Fe ₃ O ₄ and γ-Fe ₂ O ₃ with a cubic spinel structure are not completely converted to hexagonal close-packed α-Fe ₂ O ₃ when the sintering temperature is low and the time is short in pelletization. , Unstable α-Fe ₂ O ₃ with some lattice defects. Therefore, in this example, the mixed powder was not accompanied by the transformation into the hexagonal close-packed type completely, and as described above, the metal element in the PCB was dissolved in iron, resulting in lattice defect hematite. It is said that the diamagnetic arrangement is disturbed in the crystal, resulting in weak ferromagnetism.

As shown in FIG. 15, the average magnetic substance recovery rate tended to be the highest at a mixing ratio of 6: 4 for any mixed powder. The divalent FeO mixed powders were 91.18% and 91.84%, respectively, at a mixing ratio of 6: 4 and 5: 5, and showed only 90% or more. Next, a powder in which Fe ₃ O ₄ was mixed at a ratio of 6: 4 showed a high magnetic ratio of 81.81%. The ratio of Fe ₂ O ₃ powder was the lowest, and it was 66.15% even at the highest 6: 4 mixing condition. Although the ratio of Fe (OH) ₃ mixed powder was higher than that of Fe ₂ O ₃ mixed powder, the mixing ratio of 6: 4, which showed the highest value, was 77.46%, which was a mixture of FeO and Fe ₃ O ₄ It did not reach.

As shown in FIG. 16, the average distribution ratio of the metal component to the magnetic side is the highest distribution ratio in the powder in which FeO is mixed at a ratio of 6: 4, except for Ni, which has low reliability, and Cu, Fe, Sn, The total Pb and metal components were 90.11%, 97.50%, 86.83%, 82.71% and 94.88%, respectively. The FeO mixed powder showed a magnetic side partition ratio of 80% or more only in all the metal elements and all metal components.

Divalent Fe is easily oxidized and has the property of easily moving to trivalent, and Fe forms the most stable compound with trivalent. The reason why the FeO mixed powder is most magnetized is the crystal structure of FeO. FeO, a divalent iron oxide, is an iron oxide that is not very balanced in terms of crystal structure, and because of its unstable state, it tends to bind and stabilize in various molecules in the air. It is thought that many non-ferrous metal elements were adsorbed and reacted to produce the most magnetic material from the disorder of the crystal structure. Fe ₃ O ₄ has the second highest magnetic fraction and metal side distribution ratio next to FeO, and is a reverse spinel type in which divalent and trivalent Fe coexist and has a black cubic crystal defect. Structure.

On the other hand, Fe ₂ O _3, which is a trivalent iron oxide, has the most stable dense cubic structure, and is considered to have exhibited the lowest magnetic substance production and magnetic side partition ratio. There is a ferritization method in which Fe ₂ O ₃ is mixed and recovered as a magnetic material. Usually, dry ferrite treatment is performed by heating Fe ₂ O ₃ at 1673K or higher in the air to form Fe ₃ O ₄ Therefore, enormous costs are expected to be required. In addition, the trivalent Fe (OH) ₃ used in this example has the most stable structure among iron hydroxides, and is the _second lowest magnetic substance generated after Fe ₂ O ₃ and the magnetic side distribution of metal components. It is thought that the rate was shown.

From the above points in this example, the optimum conditions for performing the magnetic materialization treatment in which the metal components in the PCB powder are most efficiently concentrated are mixed with the PCB powder and FeO at a ratio of 6: 4 and air-oxidized at 1073K. It was to let you.

Next, an example of a high gradient magnetic sorting device will be described. A high-gradient magnetic separation device is effective for separating magnetic and non-magnetic particles. Conventional techniques for separating magnetic and non-magnetic materials include magnetic drum type and magnetic belt type magnetic separation devices, and wet high gradient magnetic separation devices. However, in the magnetic drum type or magnetic belt type magnetic separation device, there is a problem that fine particles having a size of about 250 μm or less are scattered even if they are processed. In the wet high gradient magnetic fractionation apparatus, components other than valuable metals are melted in the liquid to be used, so that the work is complicated, for example, it is necessary to remove these components.

Therefore, in this embodiment, an example of a dry type high gradient magnetic separation apparatus that does not use liquid will be described. FIG. 17 is a block diagram showing the structure of the high gradient magnetic sorting apparatus. This high gradient magnetic fractionation device 1 includes a sample loading unit 2, a blower unit 3 for blowing a gas to the loaded sample to uniformly disperse the sample, a magnetic head (not shown), and a matrix 4 of a fibrous metal mesh. A high gradient magnetic separation unit 5, a vibration unit 6 that applies vibration to the matrix 4 of the fibrous metal mesh, a magnetized material recovery unit 7, and a non-magnetized product recovery unit 8. Further, it is possible to switch whether the sample that has exited the high gradient magnetic separation unit 5 is sent to the magnetized product recovery unit 7 or to the non-magnetized product recovery unit 8.

The air blowing unit 3 is provided between the sample feeding unit 2 and the high gradient magnetic separation unit 5 and uniformly disperses the sample to be introduced by mixing a gas such as air with the sample that has been introduced. The matrix 4 provided in the high gradient magnetic separation unit 5 is a member configured in a mesh shape with a steel wire or a fibrous metal.

The vibrating unit 6 is operated to vibrate the matrix 4, and a sample in which a magnetized material and a non-magnetized material are mixed is loaded from the sample loading unit 2 in a state where a magnetic force is applied to the matrix 4 by the magnetic head. Here, it is preferable to introduce a powder of about 250 μm or smaller as a sample. The input sample is uniformly dispersed by the gas supplied from the blower unit 3 and is brought into a state in which it efficiently contacts the matrix 4. The matrix 4 is magnetized, and the magnetized material supplied to the matrix 4 adheres to the matrix 4. On the other hand, the non-magnetized material passes through the matrix 4 and a part of the non-magnetized material adhering to the matrix 4 together with the magnetized material is detached from the matrix by the vibration of the matrix 4 and discharged from the high gradient magnetic separation unit 5. Is done. Here, it is set so that the sample exiting the high gradient magnetic separation unit 5 is sent to the non-magnetized substance recovery unit 8. In this way, the non-magnetized material that has passed through the matrix 4 is recovered by the non-magnetized material recovery unit 8.

Next, it is set so that the introduction of the sample is stopped and the sample exiting the high gradient magnetic separation unit 5 is sent to the magnetized material recovery unit 7. Then, the matrix 4 is brought into a state where no magnetic force is applied. The vibration unit 6 is operated as necessary to vibrate the matrix 4. When the magnetic force is lost and the matrix 4 vibrates, the magnetized material adhering to the matrix 4 is detached from the matrix 4 and recovered by the magnetized material recovery unit 7. When the magnetized material adhering to the matrix 4 is almost recovered, the sample is again charged. As described above, the magnetized product and the non-magnetized product can be separately collected by repeating this operation alternately.

As described above, the magnetized product and the non-magnetized product can be efficiently separated and recovered by the dry treatment process. Since no liquid is used, the post-treatment process for extracting valuable metals from the magnetized product is simplified. This high gradient magnetic separation apparatus is also suitable for powders of about 250 μm or smaller, and is particularly suitable for application to the metal recovery processing method of the present invention.

In the present invention, it is possible to make the valuable metal magnetized by subjecting the fine powder after mixing and homogenization to a magnetizing treatment (heating treatment) at a lower temperature than in the prior art. It can be used as a metal recovery processing method that can reduce the input energy to the metal. For example, valuable metals such as gold Au can be recovered and recycled from waste such as used personal computers.

Claims (5)

A method for recovering a metal, comprising mixing a metal-containing fine powder with an iron compound and heating to magnetize the powder of the iron compound containing the metal component. The metal recovery treatment method according to claim 1, wherein the iron compound is iron oxide. The metal recovery treatment method according to claim 1 or 2, wherein the magnetized product and the non-magnetized product are separated by a magnetic force. The metal recovery treatment method according to any one of claims 1 to 3, wherein heating is performed at a temperature lower than the melting point of the glass fiber. A sample input unit, a blowing unit that blows gas to the introduced sample to uniformly disperse the sample, a high gradient magnetic separation unit that includes a magnetic head and a fibrous metal mesh, and a vibration to the fibrous metal mesh A high-gradient magnetic separation device having a vibrating part to be applied, a magnetic substance recovery part, and a non-magnetic substance recovery part.

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