JP6465825B2 - Method and apparatus for recovering precious metals from incinerated ash - Google Patents

Description

  The present invention relates to a method and apparatus for recovering precious metals from incinerated ash.

  Wastes such as general waste and industrial waste are incinerated, and incinerated ash generated by incineration has been disposed of in landfills.

  Recently, in order to protect resources and the environment, attempts have been made to collect and effectively use valuable materials contained in incineration ash, and to reduce the amount of incineration ash carried to landfill sites.

The incineration ash treatment system described in Patent Document 1 uses cement raw materials (Fe ₂ O ₃ , CaO, Al ₂ O ₃ , SiO ₂ ) and mixed metals (Fe, Cr, Ni, Cu) in the incineration ash. The incineration ash after separating the magnetic material is introduced into a dry ball mill to finely grind the soft cement raw material, while the hard mix metal is fixed to a certain extent. Grind until. The incinerated ash after pulverization is introduced into a sieving machine, and the cement raw material with a small classified particle size and the mixed metal with a large classified particle size are separated, and the cement raw material is reused as cement raw material, and the mixed metal is recycled. It will be sold to the contractor.

JP 2009-56362 A

  The incineration ash treatment system described in Patent Document 1 is intended to recover valuable materials contained in the incineration ash for effective use. However, the incineration ash is a soft material that is soft and has a small classified particle size. And the mixed metal, which is hard and has a large classified particle size, is merely separated into those two.

  Therefore, in the incineration ash treatment system described in Patent Document 1, the particles containing the precious metal in the incineration ash are selected from other particles not containing the precious metal with high sorting accuracy, and the precious metal is recovered with high quality. There is no place.

  In particular, the precious metals that were mixed in the waste and melted during the incineration of the waste were deposited on other substances in the waste that had been separated before the incineration, and in the incineration ash When noble metal adhering particles are formed, there is no way to select the noble metal with high selection accuracy from the incinerated ash containing the noble metal adhering particles.

  An object of the present invention is to recover the noble metal with high quality from the incinerated ash containing the noble metal adhering particles to which the noble metal mixed in the waste is adhered.

The invention according to claim 1 is a method for recovering precious metal from incinerated ash that recovers precious metal from incinerated ash containing precious metal adhering particles adhering to the precious metal mixed in the waste, and crushing the incinerated ash, A crushing process that generates noble metal-concentrated particles containing noble metal parts scraped from the surface of the precious metal-adhered particles in the incineration ash and other particles, and the noble metal-concentrated particles obtained in the crushing process and other particles are fixed A precious metal-enriched particle that has been classified by the specific gravity-separating step , comprising a classification step of classifying into particles, and a specific gravity-sorting step of selecting particles classified in the classification step and selecting precious metal-enriched particles from other particles High magnetic sorting is performed by magnetizing magnetizable metal contained in heavy ash containing 8000 to 12000 gauss with a magnetic field of 8000 to 12000 gauss, and non-magnetizable noble metal contained in heavy ash is magnetically deposited as described above. Sorting with sex metal High magnetic separation step in which further was set to have.

In the invention according to claim 2 , in the invention according to claim 1 , the noble metal adhering particles in the incineration ash are in a separated state before the incineration of the noble metal in the waste melted in the incineration process of the waste. It is formed by welding to other substances in the waste.

The invention according to claim 3 is the invention according to claim 1 or 2 , wherein the noble metal is gold, silver or copper.

The invention according to claim 4 is a precious metal recovery device from incineration ash that recovers precious metal from incineration ash containing precious metal adhering particles to which precious metal mixed in waste is adhered, and crushes the incineration ash, A crusher that produces precious metal concentrated particles containing precious metal parts scraped from the surface of the precious metal adhering particles in the incineration ash and other particles, and the precious metal concentrated particles obtained by the crusher and other particles are fixed to each other. a classification device for classifying the grain size, the classified particles in the classification device by gravity separation and a specific gravity sorter for sorting precious metal concentrate particles from other particles, sorted by the gravity sorter noble metal enriched particles High magnetic sorting is performed by magnetizing magnetizable metal contained in heavy ash containing 8000 to 12000 gauss with a magnetic field of 8000 to 12000 gauss, and non-magnetizable noble metal contained in heavy ash is magnetically deposited as described above. High magnetic force for sorting It is obtained as further comprising a separate machine.

In the invention according to claim 5 , in the invention according to claim 4 , the noble metal adhering particles in the incineration ash are in a separated state before the incineration of the noble metal in the waste melted in the waste incineration process. It is formed by welding to other substances in the waste.

The invention according to claim 6 is the invention according to any one of claims 4 to 5 , wherein the noble metal is gold, silver or copper.

(Claims 1, 3 , 4 , 6 )
(a) Particles containing precious metals in incineration ash by generating precious metal enriched particles containing precious metal parts such as gold, silver, and copper scraped from the surface of precious metal adhering particles in incineration ash by crushing incineration ash The concentration of noble metals can be highly concentrated. After that, the precious metal enriched particles in the incinerated ash are classified to a certain particle size together with other particles, and the precious metal enriched particles are classified by specific gravity from the classified particles of the certain particle size. The particles containing the noble metal can be sorted with high sorting accuracy from the other particles not containing the noble metal, and as a result, the noble metal can be recovered with high quality.

(Claims 1 and 4 )
(b) High magnetic force selection is performed by magnetizing the magnetically adherent metal contained in the heavy ash containing the precious metal-concentrated particles selected in the specific gravity selection step of (a) above by a magnetic field of 8000 to 12000 gauss. By sorting the non-magnetizable noble metal contained in the heavy ash from the magnetized metal, the non-magnetizable noble metal can be recovered with high quality.

(Claims 2 and 5 )
(c) Precious metals that have been mixed in the waste and melted during the incineration of the waste, are welded to other substances in the waste that were separated before the incineration, and incineration ash When noble metal-adhered particles are formed therein, the precious metal can be recovered with high quality by treating the incinerated ash containing the noble metal-adhered particles according to the above (a) and (b).

FIG. 1 is a schematic diagram mainly showing a crushing step and a classification step of the incineration ash treatment system. FIG. 2 is a schematic diagram mainly showing a specific gravity sorting step and a high magnetic force sorting step of the incineration ash treatment system. FIG. 3 is a schematic view showing a rotary impact mill. FIG. 4 is a schematic diagram showing an air table. FIG. 5 is a schematic view showing a high magnetic force sorter.

  The present invention relates to a system for treating incineration ash generated by incineration of waste such as general waste and industrial waste, and incineration including precious metal adhering particles to which precious metals such as gold, silver, and copper mixed in the waste adhere. The precious metal is recovered from the ash and the incinerated ash with reduced lead content is selected.

  Here, in the present invention, the noble metal adhering particles in the incineration ash may be any noble metal adhering particles that have come to exist in some form in the incineration ash, in particular, the molten metal in the incineration process of waste The precious metal in the waste is produced by welding to other substances such as iron and porcelain in the waste that were in a separated state before incineration.

  In the incineration ash treatment system according to the present invention, as shown in FIGS. 1 and 2, for the incineration ash of waste, the magnetic separation process, the crushing process, the classification process shown in FIG. 1, the magnetic separation process, the specific gravity selection process shown in FIG. The high magnetic force selection process is sequentially performed as follows.

(1) Magnetic separation process (Fig. 1)
Incinerated ash composed of a group of particles incinerated by an incineration facility and classified to a certain particle size by a vibrating sieve is charged into a quantitative feeder 10 such as a belt feeder.

  The incinerated ash that is quantitatively supplied from the quantitative feeder 10 to the conveyor 11 is removed of magnetic components such as iron in the process of passing below the suspended magnetic separator 12.

(2) Crushing process (Figure 1)
The incinerated ash that has passed through the suspended magnetic separator 12 in (1) above is fed into the crusher 20 by the transport conveyor 13.

  The crusher 20 crushes the incineration ash and scrapes the noble metal concentrated particles including the noble metal portion from the surface of the noble metal adhesion particles in the incineration ash. Thereby, the crusher 20 produces | generates a noble metal concentration particle | grain and other particle | grains.

  As the crusher 20, the rotary impact mill 100 shown, for example in FIG. 3 is employable. The rotary impact mill 100 includes a drum 101 that rotates at a low speed and a rotor 102 that is coaxial with the drum 101 and rotates at a high speed. A plurality of repulsion plates 103 are detachably provided on the inner periphery of the drum 101. A feed blade 104 is spirally attached between the repulsion plates 103. When the drum 101 is rotated, the incineration ash charged from the raw material charging unit 111 repeats a falling and rising motion in the drum 101, and the raw material discharging unit. It is transferred to 112. Further, striking plates 105 are attached to the outer periphery of the rotor 102 at an equal interval with an inclination. The raw material charged from the raw material charging unit 111 falls on the striking plate 105 of the rotor 102 that rotates at a high speed, and the jumping raw material collides with the repulsion plate 103 of the drum 101 that rotates at a low speed, thereby further pulverizing. become.

  Dust generated when the incineration ash is crushed by the crusher 20 is generated from the cyclone 22 to which the suction negative pressure of the suction blower 21 is applied and the dust collection hood 106 of the rotary impact mill 100 connected to the bag filter 23. It is collected. The bag filter 23 is accompanied by an air compressor 24.

(3) Classification process (Figure 1)
The precious metal-enriched particles and other particles in the incinerated ash crushed by the crushing and fixing of (2) above are classified into a certain particle size by, for example, the following classification process.

  In the primary classification process, the incinerated ash is primarily classified by the vibrating sieve 31 having a mesh size of 5 mm, and a particle group (particle group in which noble metal enriched particles and other particles are mixed) with a particle size exceeding 5 mm is recovered from the sieve. Collect the particle group (particle group in which noble metal concentrated particles and other particles are mixed) from the sieve under the particle size of 5 mm or less.

  In the secondary classification step, the primary classified incinerated ash consisting of particle groups with a particle size of 5 mm or less is secondarily classified by the vibrating sieve 32 with a mesh size of 3 mm, and the particle groups with a particle size of 3 mm to 5 mm (precious metal concentration) Particle group containing particles and other particles), and collecting a particle group having a particle size of 3 mm or less (particle group containing noble metal enriched particles and other particles) from under the sieve.

  In the tertiary classification process, the secondary classified incinerated ash consisting of particle groups with a particle size of 3 mm or less is subjected to tertiary classification with a vibrating sieve 33 with a mesh size of 2 mm, and particle groups with a particle size of 2 mm to 3 mm (precious metal concentration) Particle group containing particles and other particles), and collecting a particle group having a particle size of 2 mm or less (particle group containing noble metal concentrated particles and other particles) from under the sieve.

  In the quaternary classification process, the incinerated ash consisting of the particle groups having a particle size of 2 mm or less subjected to the tertiary classification is quaternary classified by the vibrating sieve 34 having a sieve size of 1 mm, and the particle groups having a particle size of 1 mm to 2 mm (precious metal concentration) Particle group containing particles and other particles) is collected, and a particle group having a particle size of 1 mm or less (particle group containing precious metal-enriched particles and other particles) is collected from under the sieve.

  Each incineration ash having a fixed particle size (3 mm to 5 mm, 2 mm to 3 mm, 1 mm to 2 mm, 1 mm or less) classified in each classification step by the vibrating sieves 32 to 34 in (3) above is provided for each fixed particle size. In addition, they are introduced into the magnetic separation process, the specific gravity selection process, and the high magnetic force selection process of (4) to (6) below.

(4) Magnetic separation process (Figure 2)
Each incineration ash classified in each classification step by the vibration sieves 32 to 34 in (3) above is charged into a quantitative feeder 40 such as a belt feeder. Incinerated ash that is quantitatively supplied from the quantitative feeder 40 to the transport conveyor 42 via the transport conveyor 41 is removed of magnetic substances such as iron in the process of passing below the suspended magnetic separator 43.

  Dust generated around the conveyors 41 and 42 is collected by local dust collectors 44 and 45.

(5) Specific gravity selection process (Figure 2)
The incinerated ash that has passed through the suspended magnetic separator 43 in (4) above is fed into the dry specific gravity sorter 50 by the bucket conveyor 46.

  The specific gravity sorter 50 sorts particles in each incineration ash having a constant particle size classified in each classification step by the vibrating sieves 32 to 34, and sorts precious metal-enriched particles in the incineration ash from other particles. To do.

  The specific gravity sorter 50 collects the light ash L having a small specific gravity and the heavy ash H having a large specific gravity by the specific gravity sorting of the incinerated ash. The heavy ash H selected by the specific gravity sorter 50 includes a large amount of noble metal concentrated particles in the incinerated ash, and the light ash HL includes a large amount of other particles in the incinerated ash. The specific gravity sorter 50 also sorts the light ash L with reduced lead content from the incinerated ash.

  As the specific gravity sorter 50, for example, an air table 200 shown in FIG. 4 can be adopted. The air table 200 has a vibrating table surface 201 that is inclined at a predetermined angle and receives the incinerated ash charged from the bucket conveyor 46, and a plurality of small ventilations that allow an air flow to pass from the lower surface to the upper surface of the table surface 201. A screen (net) 202 having a mouth is provided. The air table 200 includes a blower fan 203 that applies a blown air flow from the lower surface to the upper surface of the table surface 201 via a screen 202, and a suction fan 204 that applies a suction air flow to the upper surface from above the table surface 201. The air table 200 imparts vibration along the inclination direction to the table surface 201 while floating the incineration ash on the table surface 201 from the upper surface of the table surface 201 by the blowing air flow and the suction air flow over the table surface 201, and the specific gravity is increased. A fluidized bed F is formed on the table surface 201 with the heavy ash H having a large lower layer and the light ash L having a small specific gravity serving as an upper layer. The lower heavy ash H receives frictional force and vibration force from the slope of the table surface 201 and moves to the upper heavy object side, and the upper lightweight ash L does not receive frictional force and vibrational force and therefore moves to the lower lighter object side. It is washed away and separated.

  Dust generated when the incinerated ash is subjected to specific gravity sorting by the specific gravity sorter 50 is collected by the cyclone 205 and the bag filter 206 to which the suction negative pressure of the suction blower 204 is applied. The bag filter 206 is accompanied by an air compressor 207.

(6) High magnetic force sorting process (Fig. 2)
The heavy ash H containing the precious metal concentrated particles selected in the specific gravity sorting process by the specific gravity sorter 50 of (5) above is subjected to high magnetic force sorting by the high magnetic force sorter 60, and the non-magnetic property contained in the heavy ash H The noble metals such as gold, silver, and copper are sorted out against the magnetically adherent metals such as nickel and chromium.

  For example, as shown in FIG. 5, the high magnetic force sorter 60 includes a magnet drum 61 in which a high magnetic field exists, a belt conveyor (movable belt) 62 wound around the magnet drum 61, and a belt surface of the belt conveyor 62. And feeder 63 for supplying incineration ash on 62A. Reference numeral 64 denotes a separator. The incinerated ash (heavy ash H) supplied to the feeder 63 is conveyed by the belt conveyor 62 and passes over the magnet drum 61 to separate the non-magnetized substance and the magnetized substance.

  That is, when heavy ash H (mixed with gold, silver, copper, etc. and nickel, chromium, etc.) is supplied to the belt conveyor 62 and conveyed by the feeder 63, the magnetically adherent nickel, chromium, etc. are, 8000 to 12000 Gauss, in this embodiment, a magnetic field that is magnetically attached by a strong magnetic field of 10000 Gauss, flows on the belt conveyor 62 until it is no longer affected by the magnetic field of the magnet drum 61, and the position where the influence of the magnetic field disappears Fall by its own weight. On the other hand, non-magnetizable gold, silver, copper, etc. fall from the belt conveyor 61 at an early stage due to the repulsive force against the magnetic field of the magnet drum 61 and the inertial force of the rotating belt conveyor 62. Selected.

  However, the high magnetic force sorter 60 has a speed controller 65 that adjusts the rotation speed of the magnet drum 61 by the electric motor 61M. When the classified particle size of the heavy ash H put into the belt conveyor 62 is small, the speed controller 65 adjusts the moving speed of the belt conveyor 62 to the high speed side, so that the non-magnetizable noble metal and the magnetized metal This makes it possible to improve the collection accuracy of the non-adherent noble metal.

  That is, if the classified particle size of the heavy ash H put on the belt conveyor 62 of the high magnetic force sorter 60 is small, the number of particles per unit area thrown on and deposited on the belt surface 62A becomes large, and the upper layer side It is possible to cause a situation in which particles containing a magnetizable metal located at a position sandwich particles containing a non-magnetizable noble metal between the belt surface 62A.

  At this time, if the moving speed of the belt surface 62A is low, the thickness of the heavy ash H deposited on the belt surface 62A increases, and particles containing a larger number of non-magnetizable noble metals accumulate on the upper layer side. It is sandwiched between the belt surface 62A by particles containing magnetically attractable metal that is magnetically attracted to the belt surface 62A by the magnetic field of the magnet drum, and is applied to the belt surface 62A together with particles containing magnetically adherent metal. It is transferred in the attached state and falls together with the particles containing the magnetically adherent metal at the position where the influence of the magnetic field disappears. In this case, it is impossible to select particles containing noble metal such as gold, silver and copper in the incinerated ash with high magnetic accuracy with respect to particles containing a magnetic metal.

  On the other hand, when the moving speed of the belt surface 62A is adjusted to the high speed side, the thickness of the heavy ash H volume on the belt surface 62A becomes thin, and particles containing non-magnetizable noble metal are laminated on the upper layer side. Thus, the chance of being sandwiched between the belt surface 62A by particles including magnetically attractable metal attracted to the belt surface 62A by the magnetic field of the magnet drum is reduced. Further, the inertial force applied from the belt surface 62A by the particles including the non-magnetic noble metal becomes large. For this reason, the particles containing the non-magnetizable noble metal are quickly caught by the large inertial force applied from the belt surface 62A without being entrained between the belt surface 62A and the particles containing the magnetizable metal. It falls away from the belt surface 62A at the time. In this case, it is possible to sort particles containing non-magnetizable gold, silver, copper or the like in the incinerated ash with high sorting accuracy with respect to particles containing magnetized metal.

  Table 1 shows that the heavy ash H obtained by carrying out the specific gravity sorting in (5) above for each of the incinerated ash classified into the classified particles G in the classification step in (3) above is classified as high magnetic force with a magnetic field of 10000 gauss. When the moving speed V of the belt conveyor 62 is adjusted at the time of sorting with high magnetic force by the machine 60, the results of investigation of the amount of silver collected by sorting with high magnetic force are shown. A small amount, a small amount and an intermediate amount, a large amount, especially a large amount, respectively, are indicated by small, medium, many, and special.

  According to Table 1, it can be seen that as the classified particle size G is reduced to 1 to 2 mm, and further to 0 to 1 mm, the silver concentration can be improved as a result of the concentration of silver contained in each particle being concentrated. Further, it is recognized that the silver recovery amount can be improved as the belt speed V of the high magnetic force sorter 60 is increased to 1.6 m / s and further to 1.8 m / s. When the belt speed V of the high magnetic force sorter 60 exceeds 2.0 m / s, the inertial force applied to each particle becomes excessive and the magnetic force sorting accuracy is impaired.

  Table 2 shows the survey results of the amount of gold recovered, similar to Table 1 regarding the amount of silver recovered.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) Particles containing precious metals in incineration ash by generating precious metal enriched particles containing precious metal parts such as gold, silver, and copper scraped from the surface of precious metal adhering particles in incineration ash by crushing incineration ash The concentration of noble metals can be highly concentrated. After that, the precious metal enriched particles in the incinerated ash are classified to a certain particle size together with other particles, and the precious metal enriched particles are classified by specific gravity from the classified particles of the certain particle size. The particles containing the noble metal can be sorted with high sorting accuracy from the other particles not containing the noble metal, and as a result, the noble metal can be recovered with high quality.

  (b) The heavy ash H containing the precious metal concentrated particles selected in the specific gravity selection step of (a) described above is subjected to high magnetic force selection, and the non-magnetizable precious metal contained in the heavy ash H is magnetized. The non-magnetizable noble metal can be recovered with high quality.

  (c) Precious metals that have been mixed in the waste and melted during the incineration of the waste, are welded to other substances in the waste that were separated before the incineration, and incineration ash When noble metal-adhered particles are formed therein, the precious metal can be recovered with high quality by treating the incinerated ash containing the noble metal-adhered particles according to the above (a) and (b).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the said noble metal can be collect | recovered with high quality from the incineration ash containing the noble metal adhesion particle to which the noble metal mixed in the waste adhered.

20 Crusher 31 to 34 Vibrating sieve (classifier)
50 Specific gravity sorter 60 High magnetic force sorter L Light ash H Heavy ash

Claims (6)

A method for recovering precious metals from incineration ash that recovers precious metals from incineration ash containing precious metal adhering particles to which precious metals mixed in waste are attached,
A crushing step of crushing the incineration ash to produce noble metal concentrated particles containing noble metal parts scraped from the surface of the noble metal adhesion particles in the incineration ash, and other particles,
A classification process for classifying the precious metal-enriched particles obtained in the crushing process and other particles into a certain particle size;
A specific gravity selection step of selecting particles classified in the classification step and selecting precious metal concentrated particles from other particles ;
The magnetic ash containing the noble metal-concentrated particles selected in the specific gravity selection step is subjected to high magnetic force selection by magnetizing with a magnetic field of 8000 to 12000 gauss and contained in the heavy ash. A method for recovering a noble metal from incinerated ash , further comprising a high magnetic force sorting step for sorting a non-magnetizable noble metal from the above-mentioned magnetized metal . Precious metal adhering particles in the incineration ash are formed by welding the precious metal in the waste melted in the waste incineration process to other substances in the waste that were in a separated state before incineration The method for recovering precious metals from incinerated ash according to claim 1 . The method for recovering noble metal from incinerated ash according to claim 1 or 2 , wherein the noble metal is gold, silver or copper. A precious metal recovery device from incineration ash for recovering precious metal from incineration ash containing precious metal adhering particles to which precious metal mixed in waste has adhered,
A crusher that crushes the incinerated ash and generates noble metal-enriched particles containing noble metal parts scraped from the surface of the noble metal adhering particles in the incinerated ash, and other particles;
A classifier that classifies the precious metal-enriched particles obtained by the crusher and other particles into a certain particle size;
A specific gravity sorter that sorts the particles classified by the classifier by specific gravity and sorts the precious metal concentrated particles from other particles ;
High magnetic force sorting is performed by magnetizing a magnetically adherent metal contained in heavy ash containing noble metal-concentrated particles sorted by the specific gravity sorter with a magnetic field of 8000 to 12000 gauss, and is contained in this heavy ash. An apparatus for recovering noble metal from incinerated ash , further comprising a high magnetic force sorter for sorting non-magnetizable noble metal from the above-mentioned magnetized metal . Precious metal adhering particles in the incineration ash are formed by welding the precious metal in the waste melted in the waste incineration process to other substances in the waste that were in a separated state before incineration The precious metal recovery device from incinerated ash according to claim 4 . The precious metal recovery device from incinerated ash according to claim 4 or 5 , wherein the precious metal is gold, silver or copper.

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