JPH08192069A - Method of recovering valuable metal from motor scraps by low temperature crushing - Google Patents

Abstract

PURPOSE: To effectively separate combined different kinds of metals constituting a small volume of solid by crushing cooled motor scraps by a low temperature crusher whose opening size per grate bar is a specified value or less and subjecting the crushed motor scraps to magnetic separation. CONSTITUTION: After scraps of electric household appliances including small- sized motors and of disused cars are crushed by a shredder, the separated and recovered motor scraps are cut by a cutting device 1. The cut motor scraps are conveyed by a conveying/precooling device 2 and at the same time, are precooled. The conveyed and precooled motor scraps are brought into contact with a cooling medium consisting of liquefied gas in a cooler 3 to cool them to a brittle temp. region of iron base metal. The cooled motor scraps are crushed by a low temp. crusher 4 whose opening size per grate bar is >=30cm<2> . The crushed motor scraps are subjected to magnetic separation in a cleaner 5. In this way, combined metals of different kinds constituting a small volume of solid are effectively separated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering valuable metals from household electric appliances including small motors and scrapped automobiles, and particularly finely crushing them by low temperature crushing to separate iron core and copper winding from each other. The present invention relates to a method for efficiently recovering copper.

[0002]

2. Description of the Related Art Generally, it is very difficult to remove copper-based impurities such as small motors contained in household electric appliances and scrap scraps of iron in the melting and refining stage of the steelmaking process due to the chemical characteristics of iron and copper. Have difficulty. Therefore, at present, as a pretreatment, separation is performed in a solid state.
Conventionally, scrap car scraps are shredded with a shredder machine, and from the shredded material, non-metallic dust such as glass, rubber and plastics, and non-ferrous metals such as aluminum, copper and zinc are separated by means such as an air separation device, a magnetic separation device and a sieving machine. It is a general method to separate metals and recover iron scrap.

However, due to the high technology in the automobile industry and the expanding needs of consumers in recent years, the composite of automobile components has been remarkably increased by diversifying their functions and hybridizing devices. Therefore, in order to recover iron scrap from the generated waste automobile and recycle it as an iron resource, there is a problem that copper or the like, which is a difficult-to-separate element, is difficult to separate. For example, the usage pattern of copper causes an increase in the number of small motors used by electrifying members, or an increase in the number of electronic control parts and electrical wiring accompanying it due to automatic control, and these are further compounded to further increase. The amount has increased. For this reason,
In the conventional method, small motors are removed from the shredder iron scraps by manual selection.In these removed small motors, the iron core of the motor core, the copper windings, and the copper wirings caught in the iron members are magnetically separated. Separation is difficult, so iron and copper were processed without separation.

On the other hand, as a method for economically crushing iron scrap, a method has been proposed in which the iron member is cooled to a temperature lower than the embrittlement temperature by immersing it in a refrigerant such as liquid nitrogen or is crushed, and then separated. ing. As a known technique in this field, for example, in Japanese Examined Patent Publication No. Sho 47-36121, scrap is pre-compressed into a block having many gaps, and liquid nitrogen at −60 to −120 ° C. is passed through the block.
A method of compressing and crushing in a cooled state is disclosed. Further, JP-A-48-21847 discloses a suitable crushing device for carrying out the method of the above-mentioned publication. In this way, by lowering the temperature of scrap and crushing it,
An iron member which itself has the property of exhibiting embrittlement at a low temperature is finely crushed at that temperature, and a member such as aluminum or copper that does not have the low temperature embrittlement property remains uncrushed. In this state, the crushed materials could be magnetically separated by their magnetic characteristics, and iron scrap was collected. Further, Japanese Patent Application Laid-Open No. 5-331565 discloses a method of removing or destroying the enamel coating of motor scraps, depositing them in a leaching tank, and electrolytically recovering a copper component using ammine as a leaching solution.

[0005]

The above-mentioned conventional low-temperature crushing or liquid leaching method is intended to replace the conventional crushing of iron scrap by shredder with these methods. Therefore, there is naturally a limit in recovering valuable metals such as iron and copper from small motor scraps in a recyclable form. Further, practically, separation at a fine crushing level is essential, but from this point, there is still a problem, and its solution has been a problem.

An object of the present invention is to examine a method for recovering valuable metals from small motor scraps, which is an alternative to the above-mentioned low temperature crushing and liquid leaching method, from the viewpoint of practical use, and to form a composite solid heterogeneous material having a small capacity. It is to provide a method for effectively separating metals. That is, the present invention provides a low-temperature crushing fractionation method that enables efficient cooling by refining by a refrigerant body and by recycling the refrigerant body and examining the pre-cooling function of a packed bed type. To do.

[0007]

Means for Solving the Problems The present invention achieves the above objects, and the gist thereof is as follows: (1) Home appliances including small motors and scraps of scrapped vehicles are shredded, and then sorted and collected. Motor scraps are cut out by a cutting device and transported and pre-cooled at the same time as a transport / pre-cooling process. The transported / pre-cooled motor dust is brought into contact with a refrigerant consisting of liquefied gas to cool it to the embrittlement temperature range of ferrous metals. The cooling step, the low temperature crushing step of crushing the cooled motor waste by a low temperature crusher having an opening size of 30 cm ² or less per great bar, and the selective step of magnetically separating the crushed motor waste. Characteristic method of recovering valuable metals by low-temperature crushing of motor waste.

(2) In the carrying / preliminary cooling step,
A valuable metal recovery by low-temperature crushing of motor waste according to (1), characterized in that a packed bed is formed by the motor waste and the refrigerant used in the low-temperature crushing step is circulated through the packed bed to precool the motor waste. Method.

(3) The method of recovering valuable metals by low-temperature crushing of motor scrap as described in (1), wherein the selecting step is performed by applying vibration stress.

[0010]

According to the present invention, iron and copper as valuable metals can be separated from the small motor scraps in the shredder scraps that have been disposed of in the past, so that they can be recovered for recycling for utilization of metal resources. It was possible to use. Further, the present invention improves the conventional low temperature crushing, that is, in order to enable fine crushing of motor waste on an actual machine basis, the refrigerant body used in the low temperature crushing process is recycled and used in the pre-cooling process, and Improving the heat exchange function, that is, increasing the solid-gas (refrigerant gas) ratio in the pre-cooling step by filling the motor waste, increasing the solid-gas contact time,
By sufficiently exchanging heat, the efficiency of cooling to the brittle temperature range of iron for low-temperature crushing was improved, and fine crushing separation was realized from small motor scrap, enabling recovery of valuable metals.

According to the present invention, in order to effectively recycle the entire amount of motor scraps that have been disposed of in the scrap processing of household electric appliances and scrapped vehicles as a resource, it is possible to finely crush the scraps by low temperature crushing. , And its crushed state are most advantageous for the separation of complexed iron and copper,
This was achieved by noting that brittle fracture can be used. Further, in the method of the present invention, as a great bar of a low temperature crusher, the opening size per great bar is 30c.
The requirement for low-temperature crushing is that it is m ² or less. this is,
If the great bar of the low temperature crusher has an opening size of more than 30 cm ² per great bar, the iron and copper of the motor waste will not be separated into individual substances and iron and copper will be recovered from the target small motor waste. This is because sufficient crushing cannot be achieved.

Furthermore, the low temperature crusher of the present invention is preferably a rotary hammer type crusher, and the shape and arrangement of the gaps thereof are rectangular or oblong, and the short side thereof with respect to the rotation of the hammer. It is better to arrange them in the direction of the hammer rotation. This is because the crushing efficiency is affected depending on the gap direction. The shape after crushing the motor chips is a mixture of flaky iron core and linear copper. In this state, if the treatment is carried out in the selective step of magnetic separation, the linear copper is sandwiched between the thin pieces, the nonmagnetic copper is mixed into the iron which is a magnetic material, and the separation effect is not good.
Therefore, iron and copper (magnetic and non-magnetic materials) are used for magnetic separation.
It is necessary to create a state in which the particles are isolated (single-part separated state). As a means for this, magnetic separation is performed in the state in which vibration stress such as hammering and shaking is added. It should be noted that the present invention is not limited to the recovery of valuable metals from small motor scraps, and application to other copper-containing scrap treatment, for example, does not depart from the gist of the present invention, and composite heterogeneous metals. Needless to say, the present invention can be applied to the recovery of valuable metals from other iron scraps containing iron. Hereinafter, the present invention will be described in more detail based on examples.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a flow chart of an apparatus for realizing the iron scrap processing method of the first invention of the present invention. The cutting device 1 is a device for sending out, as a form of motor waste, motor waste collected from a scrapped car crushed by an ordinary shredder machine to a transport / preliminary cooling device. The motor waste sent out is transported by the transport / preliminary cooling device 2 and preliminarily cooled by heat exchange with the cold exhaust gas generated in the cooling device, and then charged into the cooling device 3. Cold liquefied gas, such as liquid nitrogen, is stored in the cooling device 3, and motor chips are immersed or contacted in the liquefied gas and cooled to the embrittlement temperature range of iron.

At this time, the inside of the apparatus is conveyed by a conveyor or a rotary drum type conveying apparatus. The cooled iron scrap is thrown into the low temperature crusher 4 and crushed. As the low temperature crusher, an impact type crusher such as a hammer crusher is preferable. The crushed motor waste is separated into magnetic iron material and non-magnetic material copper by the magnetic separation in the selective machine 5, and sent to the step of collecting by a known method.

At this time, as shown in FIG. 2, the motor waste 6 was precooled by the transport / preliminary cooling device 2 as a comparative example, when it was filled and when it was not filled like a normal conveyor type. FIG. 2A is a schematic diagram of a state in which the motor waste 6 is filled, and FIG. 2B shows a state in which the motor waste 6 is pre-cooled while being conveyed by the conventional conveyor 7. FIG. 2C is a sectional view taken along the line AA in FIG. In the present embodiment, the degree of filling can be arranged by the filling rate, and the filling rate is represented by the ratio of the average bulk specific gravity of motor scraps and the average apparent specific gravity per motor. Therefore, in the conventional conveyor type, the value of this ratio can be evaluated as the value of the ratio between the entire cross-sectional area and the area occupied by the motor waste, as shown in FIG. The overall processing flow of this embodiment is shown in FIG.
In this figure, a transport / preliminary cooling device 2 is provided between the cutting device 1 and the cooling device 3. At this time, the filling of the motor waste is performed by adjusting the charging / discharging by operating the two-stage dampers 13 provided above and below the packed bed. Thereafter, the precooled motor waste 6 is supplied to the cooling device 3 by the conveyor 7, where it is cooled to the embrittlement temperature and crushed by the low temperature crusher 4. A two-stage damper is also provided between the cooling device 3 and the low temperature crusher 4. After that, the crushed motor waste is transferred to the conveyor 7
And sent to a selection process (not shown). On the other hand, the exhaust refrigerant gas from the transport / pre-cooling device 2 and the low temperature crusher 4 is
It is discharged by the blower 16 through the cyclone 14 and the bag filter 15. The crusher used in this example is shown in FIGS. FIG. 3A shows the structure of the low temperature crusher. In this figure, the required amount of motor waste is supplied from the supply port 6 and crushed. The crusher of the present embodiment is a rotary hammer type, and a plurality of rotary hammer heads 8 are provided at equal intervals in the circumferential direction, and are rotated at high speed for crushing. At this time, the size of the motor waste after crushing is adjusted by the opening size of the gap 10 of the grit 9 arranged concentrically on the outer circumference.
FIG. 3B shows a partial cross section of the grit, and FIG. 3C is a BB arrow view of FIG. 3B, showing the arrangement of the gaps 10. In this embodiment, the gap 10 has a substantially rectangular shape,
The direction of its short side matches the direction of rotation of the hammer.

Table 1 summarizes the treatment conditions of this example treated by the above steps and the recovery results of the selected iron and copper.

[0017]

[Table 1]

[0018] Table 1 results, by the 30 cm ^2/1 piece of the present invention the grit size of the cold crusher from 60cm ^2/1 piece of the comparative example in the present embodiment, substantially iron and copper recovery Improved. Further, in the comparative example, the uncollected material was mostly the motor scrap as it was, with the iron core and the copper winding being integrated. In addition, in the packed bed type precooling of the present invention, the filling rate was increased 10 times or more, the precooling temperature was lowered, and the cold heat recovery rate was significantly improved, as compared with the conventional conveyor type precooling. Furthermore, by adding vibration to the magnetic sorting machine, the recovery rate of iron and copper is increased, the amount of copper impurities in the recovered iron is reduced, and the purity of recovered copper is increased, thereby increasing the added value of the recovered product. Increased.

[0019]

As is apparent from the above embodiments, according to the present invention, by effectively utilizing the liquefied gas at the time of low-temperature crushing the motor scrap separated from the shredder iron scrap, and efficiently performing the pre-cooling, In addition, the efficiency of fine crushing at the time of low temperature crushing can be improved, and almost all of the valuable metals iron and copper can be recovered from motor scrap, and recycling can be achieved as a resource.

[Brief description of drawings]

FIG. 1 is a diagram showing a processing flow of motor waste according to the present invention.

FIG. 2 is a view showing a filling state of motor waste according to an embodiment of the present invention, (a) a filling mold of the method of the present invention, (b) a conventional non-filling state, and (c) (b) AA FIG.

FIG. 3 shows a low temperature crusher according to an embodiment of the present invention,
(A) Configuration diagram, (b) Cross-sectional view of grit, (c) (b)
FIG.

FIG. 4 is a flowchart showing the overall processing according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cutting device 2 ... Conveying / preliminary cooling device 3 ... Cooling device 4 ... Low-temperature crusher 5 ... Selection machine 6 ... Motor waste 7 ... Conveyor 8 ... Motor waste supply port 9 ... Exhaust port 10 ... Rotating hammer head 11 ... Grit 12 ... Grit air gap 13 ... Damper 14 ... Cyclone 15 ... Bag filter 16 ... Blower

Claims (3)

[Claims] 1. A crushing machine for household appliances including small motors and scrap car scraps, and then crushing and collecting the collected motor scraps by a slicing device and carrying and precooling at the same time. A cooling process in which the motor waste is brought into contact with a refrigerant of liquefied gas to cool it to the embrittlement temperature range of the iron-based metal, and the cooled motor waste has an opening size of 30 c per great bar.
A method for recovering valuable metals by low-temperature crushing of motor scraps, characterized by performing a low-temperature crushing step of crushing by a low-temperature crusher having a m ² or less, and a fine selection step of magnetically separating the crushed motor scraps. 2. In the carrying / preliminary cooling step, a packed layer is formed by motor scraps, and the refrigerant used in the low temperature crushing step is circulated through the packed layer to precool the motor core. The method for recovering valuable metals by low-temperature crushing of motor waste according to claim 1. 3. The method for recovering valuable metals by low-temperature crushing of motor waste according to claim 1, wherein the selecting step is performed by applying vibration stress.