JP6912234B2 - Valuable metal recovery method - Google Patents

Description

The present invention relates to a method for recovering valuable metals from home appliances.

A method of recovering a mounted circuit board such as a printed wiring board from a home electric appliance and recovering a valuable metal from the board has been proposed (see, for example, Patent Document 1). According to this method, home appliances are crushed (crushing step), the crushed material is sieved and separated (sieving step), and the crushed material on the sieving is separated into magnetic and non-magnetic materials by magnetic force (the crushing process). Magnetic sorting process). The non-magnetic material is separated into metal and non-metal (vortex current sorting process), the mounting substrate is sorted from each of the metal and non-metal based on the color (color sorting process), and the mounting substrate is the mounting component and substrate. (Separation and sorting step). Then, valuable metals are recovered from the mounted parts by specific gravity sorting (specific gravity sorting step).

Japanese Unexamined Patent Publication No. 2013-000685

However, in the separation and sorting process, although the mounted parts are peeled from the mounted board by using a component peeling device, solder and copper wiring that cannot be completely peeled off and remain attached to the board, cables, coated copper wires derived from electric wires, etc. The valuable metal of was not recovered.

Therefore, an object of the present invention is to provide a method capable of further improving the recovery efficiency of valuable metals from home electric appliances.

The valuable metal recovery method of the present invention includes a primary crushing step of obtaining a primary crushed product by crushing a home appliance having a mounting substrate including a mounting component and a substrate, and a magnetically deposited primary crushed product using magnetic force. And a magnetic force sorting step of sorting into non-magnetic particles, a eddy current sorting step of sorting the non-magnetic deposits into conductive products and non-conductive products using the repulsive force of the eddy current, and by crushing the non-conductive products. In the secondary crushing step of obtaining the secondary crushed product, and using a dry specific gravity difference sorter, the secondary crushed product is a light product made of a resin-containing material, and the mounting component and the mounting component are attached to the substrate. It is characterized by including a specific gravity difference sorting step of sorting into a heavy product containing the substrate having a metal-containing substance, and a step of recovering valuable metal from the heavy product.

According to the valuable metal recovery method of the present invention, the primary crushed material of the mounting board contained in the non-conductive product is further crushed, so that not only the mounting components constituting the mounting board but also the mounting components are crushed. A secondary crushed product is obtained in which valuable metal-containing substances such as solder and copper wiring, cables, and coated copper wires derived from electric wires and resin-containing substances such as the substrate are more reliably separated from each other. Therefore, the secondary crushed product is sorted into heavy products and light products by a dry specific gravity difference sorter, so that the recovery efficiency of the valuable metal contained in the heavy products can be improved.

The flowchart of the valuable metal recovery method as one Embodiment of this invention.

Each step of the valuable metal recovery method as an embodiment of the present invention will be described.

(Primary crushing process)
A mixture of small household appliances such as a portable DVD player, a DVD player and a memory-type music player was designated as the object to be crushed P0. A manually removable substrate or the like may be removed from the product in advance. A chain type crusher was used to crush the object P0 to obtain a primary crusher P1 (FIG. 1 / STEP02). The mesh size of the crusher was set to, for example, 100 mm.

(Magnetic force sorting process)
A magnetic sorter (eg, a hanging sorter) was used to sort the primary crushed material P1 into a magnetic deposit P2 and a non-magnetic deposit P3 (FIG. 1 / STEP04). The magnetic force sorter is a device that sorts by magnetically adhering a magnetic metal such as iron. The primary crushed material P1 contains metal scraps of about several tens to several hundreds [mm], and in order to finally recover precious metals such as gold and silver, general-purpose metals such as iron, which is a magnetic deposit, are removed. Will be done.

(Eddy current sorting process)
An eddy current sorter was used to sort the non-magnetic deposits P3 into conductive products P4 and non-conductive products P5 (FIG. 1 / STEP06). Eddy current sorting is a method of sorting non-ferrous metals such as aluminum by utilizing the difference in repulsive force based on eddy current. For example, a non-magnetic material conveyed to the tip side of the conveyor belt by the interaction between the induced current generated inside by receiving the electromagnetic induction action of the moving magnetic field of the rotating magnet body provided on the tip side of the conveyor belt and the moving magnetic field. Some P3s are configured to give a thrust in the direction of rotation of the rotating magnet body and cause the non-ferrous metals to pop out from the surface of the conveyor belt in the direction of the combined force of this thrust and the gravity acting on the non-ferrous metals. As the eddy current sorting device, a rotating magnet type, a orthogonal belt conveyor type, and a rotating cylindrical type are preferable. The rotation speed of the magnetic drum was set to, for example, 2500 rpm. As a result, for example, 22% conductive product P4 and 78% non-conductive product P5 were selected from 100% non-magnetic deposit P3.

(Secondary crushing process)
A secondary crusher P6 was obtained by crushing the non-conductive product P5 using a cutter type crusher (Fig. 1 / STEP08). The secondary crushed product P preferably has a sieve mesh of 4 mm or less, and preferably 2 mm or less.

(Relative density difference sorting process)
A dry specific density difference sorter was used to sort the secondary crushed product P6 into light product P7 and heavy product P8 (Fig. 1 / STEP10). This results from 100% secondary crushed product P6 to, for example, 73% light product P7 (eg 0.7 g / cm ³ ) and 15% heavy product P8 (eg 2.9 g / cm ³ ), as well as 12%. Dust was obtained.

As a dry specific gravity difference sorter, an air table that uses both air flow and vibration is used, and objects are sorted by the difference in resistance to air flow and the ease of rolling due to vibration, that is, the frictional force on the table surface. The object is supplied from the feeder to the air table, and undergoes a separation operation by the vibration motion of the table surface and the air flow. In general, heavy objects are not easily affected by air flow, are transported by vibrating motion, and fall to one side (for example, the left side). On the other hand, a lightweight object is strongly affected by an air flow and floats to reduce friction with the table surface, slides down the slope of the table, and falls to the other side (for example, the right side). Also, the lightest ones are blown up by the air stream and collected by a dust collector (eg, a cyclone). The air table is a parameter that affects not only the air flow but also the vibration and the tilt angle of the table, and by setting these to the optimum values, precious metals can be recovered as heavy products with even higher accuracy. .. The heavy product also contains a high concentration of copper. Further, since lead and chromium, which are repellent components of cement, are also recovered from the heavy products, the amount mixed in the cement as a fuel, which will be described later, is reduced.

The dust and light products are confluent products containing 80% of the ignition material (950 ° C.) and contribute to reuse as fuel, and are crushed to 3 mm or less, more preferably 1 mm or less, and further preferably 0.1 mm or less. Used as fuel.

[Example]
[Example 1]
The sieve mesh of the crusher in the secondary crushing step (Fig. 1 / STEP08) was set to 4 mm. Table 1 shows the grade and recovery rate of each metal as a result of component analysis in each of the primary crushed product P1, the magnetic deposit P2, the non-conductive product P5, the conductive product P4, the heavy product P8 and the light product P7.

[Example 2]
The sieve mesh of the crusher in the secondary crushing step (Fig. 1 / STEP08) was set to 2 mm. Table 2 shows the grade and recovery rate of each metal as a result of component analysis in each of the primary crushed product P1, the magnetic deposit P2, the non-conductive product P5, the conductive product P4, the heavy product P8 and the light product P7. The component analysis results of the primary crushed product P1, the magnetic deposit P2, the non-conductive product P5, and the conductive product P4 are the same as those in Example 1.

As described above, the silver grade of the heavy product was 1400 g / t or more, the palladium grade was 73 g / t or more, and the gold grade was 40 g / t or more, which were high-grade raw materials for precious metal refining. The grade of copper, which is a heavy product, was 42% or more. The metal recovery rate was 68% or more for silver and 84% for palladium, indicating that precious metals can be recovered efficiently. In addition, the amount of Pb input to cement raw material has decreased to 25% or less.

[Comparison example]
Each step was carried out in the same manner as in Example 1 except that the secondary crushing step (FIG. 1 / STEP08) was omitted, but in the specific gravity difference sorting step (FIG. 1 / STEP10), the heavy product P8 and the light product P7 The densities were the same (about 0.5 g / cm ³ ), and both could not be sorted.

Claims (3)

A primary crushing process for obtaining a primary crushed product by crushing a home electric appliance having a mounting substrate including a mounting component and a substrate.
A magnetic force sorting step of sorting the primary crushed material into magnetic and non-magnetic objects using magnetic force, and
An eddy current sorting step of sorting the non-magnetic deposit into a conductive product and a non-conductive product by using the repulsive force of the eddy current.
A secondary crushing step for obtaining a secondary crushed by crushing the non-conductive product,
Using a dry specific gravity difference sorter, the secondary crushed product is made into a light product made of a resin-containing material and a heavy product containing the mounting component and the valuable metal-containing material having the mounting component attached to the substrate. Specific gravity difference sorting process for sorting and
A valuable metal recovery method comprising a step of recovering a valuable metal from the heavy product.
The valuable metal recovery method according to claim 1, wherein the dry specific gravity difference sorter is an air table. The valuable metal recovery method according to claim 1 or 2, wherein the particle size of the secondary crushed product is 4 mm or less.

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