JP6375205B2 - Valuable metal recovery method and valuable metal recovery system - Google Patents

Description

  The present invention relates to a valuable metal recovery method and a valuable metal recovery system for recovering valuable metals in waste.

  In recent years, in order to use solid waste such as construction soil and sludge as part of cement raw material and fuel, solid waste is pulverized, and the pulverized waste is of a size suitable for cement raw material and fuel. And other types of cement mills have been proposed (for example, patents), and a metal sorter that separates and removes metals from solid waste in a process upstream of the vertical mill. Reference 1).

JP 2013-28477 A

  It is known that solid waste, especially incineration ash, incineration fly ash and molten fly ash, which are municipal waste, contain valuable metals such as copper, zinc, gold, silver, palladium, platinum, etc. ing.

  However, in the cement manufacturing apparatus described in Patent Document 1, iron and aluminum can be recovered from the solid waste by the metal sorting unit. However, in the solid waste, the other metals, particularly valuable metals such as gold, are contained. However, since the content rate varies, valuable metals are not recovered and are input to the kiln as cement raw materials.

  Therefore, an object of the present invention is to provide a valuable metal recovery method and a valuable metal recovery system capable of efficiently recovering valuable metals in waste.

The present invention provides the following valuable metal recovery methods [1] to [4] and the valuable metal recovery system [5] to [6].
[1] A pretreatment step for pretreating raw material waste containing valuable metals, and a mill having a predetermined particle size distribution obtained as a result of pulverizing the raw material waste pretreated by the pretreatment step Selecting a fine powder and a mill stone containing coarse powder having a particle size distribution larger than the predetermined particle size distribution, and adjusting the predetermined particle size distribution of the mill fine powder By performing the pulverization and the sorting as described above, the ratio of the valuable metal content in the mill waste stone to the valuable metal content in the raw material waste or the mill fine powder becomes equal to or higher than the first specified value. And a recovery step of recovering the mill waste stone, and the preliminary treatment step includes at least a magnetic force selection step of magnetically selecting the raw material waste .
[2] In the valuable metal recovery method according to [1], the recovery step is a part of the mill waste stone, and contains the valuable metal in the mill waste stone with respect to the content of the valuable metal in the raw material waste. The valuable metal recovery method, wherein the mill waste stone containing a particle size in a predetermined particle size range in which a ratio of the rates is equal to or higher than a second specified value higher than the first specified value is recovered.
[3] The valuable metal recovery method according to [1] or [2], wherein the raw material waste is municipal waste incineration ash.
[4] The valuable metal recovery method according to any one of [1] to [3], wherein the valuable metal is at least one of gold and silver.
[5] A pretreatment system for pretreating raw material waste containing at least one of gold and silver as a valuable metal , the raw material waste prepared by the pretreatment system is pulverized, and the result of the pulverization is obtained. The mill fine powder having a predetermined particle size distribution and the mill stone containing coarse powder having a particle size distribution larger than the predetermined particle size distribution are selected, and the predetermined particles of the mill fine powder By performing the pulverization and the selection so as to adjust the diameter distribution, the ratio of the content of valuable metals in the mill waste stone to the content of valuable metals in the raw material waste or the mill fine powder is designated first. A valuable metal recovery system including a vertical mill that adjusts to a value equal to or higher than the value, and wherein the pretreatment system includes a magnetic separator that performs magnetic separation on at least the raw material waste .
[6] In the valuable metal recovery system according to [5], the ratio of the content of valuable metal in the mill waste stone that is a part of the mill waste stone and the content of valuable metal in the raw material waste is the ratio. A valuable metal recovery system comprising a recovery device that recovers the mill waste stone including a particle size in a predetermined particle size range that is equal to or higher than a second specified value higher than the first specified value.

  According to the valuable metal recovery method and the valuable metal recovery system of the present invention, the content of valuable metals such as gold in the mill waste is increased, and the valuable metals such as gold in the waste are efficiently recovered by collecting the mill waste. Can be recovered. Further, since the obtained mill waste stone contains valuable metals at a high content, it is extremely useful as a raw material for smelting.

The figure which shows typically the valuable metal collection | recovery system of embodiment of this invention. The figure which shows the vertical mill of a valuable metal collection | recovery system in embodiment of this invention.

[Valuable metal recovery system]
As shown in FIG. 1, the valuable metal recovery system 1 of the present embodiment includes a dryer 10, a magnetic separator 12, 12 ′, a sieving machine 14, 14 ′, 14 ″, a pulverizer 16, and an eddy current separator. And a vertical roller mill 20 (hereinafter referred to as “vertical mill”). In addition, the vertical mill 20 is sold in various types, and the type is not limited. An exemplary embodiment of the saddle mill 20 is shown in FIG.

  The raw material waste that is a raw material of the valuable metal recovery system 1 refers to a waste containing valuable metals such as copper, zinc, gold, silver, palladium, platinum, etc., in particular, gold, silver, palladium, Municipal waste incineration ash containing platinum or the like (for example, including excavated incineration ash or the like) is preferable. In addition, in this specification, valuable metals mean metals other than iron and aluminum, for example, copper, zinc, gold | metal | money, silver, palladium, and platinum.

  The pretreatment system pretreats the raw material waste supplied to the vertical mill 20. Specifically, in the pretreatment system, the water content of the raw material waste containing valuable metals is preferably 5 [wt%] or less, the maximum particle size is preferably 40 [mm] or less, more preferably 20 [mm]. The operating conditions of the vertical mill 20 are adjusted so that mill fine powder having the desired particle size distribution adjusted below can be formed.

  The dryer 10 is an apparatus that dries waste and forms raw material waste having a predetermined moisture content that conforms to the operating conditions of the vertical mill 20. In particular, when using municipal waste incineration ash, etc., it is a form in which ash is attached to metal scraps by water-cooling treatment for incineration ash etc. in a garbage incinerator, so by drying the waste, magnetic separators 12, 12 ′ Sorting in the sieving machines 14, 14 ', 14 "and the eddy current sorter 18 is facilitated.

  In addition, when the moisture content of the waste meets the operating conditions of the vertical mill 20 that can form mill fine powder having a desired particle size distribution, it is not always necessary to provide the dryer 10 in the pretreatment system.

  The magnetic separators 12 and 12 'are devices that sort magnetic metals such as iron from waste. Waste, especially municipal waste incineration ash, etc. may contain several tens [mm] to several hundred [mm] of metal scrap, so that the mill that is recovered in the stable operation of the vertical mill 20 and subsequent processes In order to increase the content of copper, zinc and noble metals in the waste stone, it is necessary to selectively remove general-purpose metals such as iron from the waste before the raw material waste is supplied to the vertical mill 20 as a raw material.

  The sieving machine 14, 14 ', 14 "is an apparatus that sorts the raw material waste supplied to the sieving machine into a waste having a predetermined particle size or less and a waste having a particle size exceeding the predetermined particle size. As shown in Fig. 1, a sieving machine 14 and a sieving machine 14 'are installed in series in the process, and sorted in the sieving machine 14 upstream of the process to form more raw material in the pretreatment system. This is because waste exceeding the predetermined particle size is supplied to a pulverizer 16, which will be described later, and the waste pulverized by the pulverizer 16 to a predetermined particle size or less is collected by a sieving machine 14 'downstream of the process.

  Note that the sieving machine 14 ″ applies non-magnetic metal particles adhering to a magnetic metal having a predetermined particle size or less to the vertical mill 20 with respect to a magnetic metal such as iron selected from waste by the magnetic separator 12 ′. In order to reduce the content of valuable metals in the mill stone to be recovered, it is not always necessary to provide a sieving machine 14 ″ in the pretreatment system.

  The pulverizer 16 is an apparatus that coarsely pulverizes raw material waste to form raw material waste having a predetermined particle size that matches the operating conditions of the vertical mill 20.

  The eddy current sorter 18 is a device that sorts aluminum from waste using a repulsive force difference based on eddy current. For example, disposal of metals transported to the front end side of the conveyor belt due to the interaction between the induced current generated by the moving magnetic field of the rotating magnetic body provided on the front end side of the conveyor belt and the moving magnetic field. There is a structure in which a thrust is applied to an object in the rotational direction of a rotating magnet body, and nonferrous metals are ejected from the surface of the conveyor belt in the direction of the combined force of this thrust and gravity acting on the nonferrous metals.

  The eddy current sorter 18 is not necessarily provided upstream of the vertical mill 20 described later, but is provided downstream of the vertical mill 20 or upstream and downstream of the vertical mill 20. Also good.

  The vertical mill 20 is obtained by milling and drying the raw material waste pretreated by the pretreatment system, and classifying the fine powder and the coarse powder into fine powder having a predetermined particle size distribution and a predetermined particle size distribution. Is a device that sorts into mill stone containing coarse powder having a particle size distribution on the large diameter side.

  Here, “the particle size distribution (of coarse powder) on the larger diameter side than the predetermined particle size distribution (of mill fine powder)” means that the particle size distribution of mill fine powder and coarse powder overlaps in two distributions. Although the presence or absence of a part is not ask | required, it means that the particle size distribution of coarse powder is located in a larger diameter side than the particle size distribution of mill fine powder.

In order to determine the particle size distribution of the mill fine powder, the operating conditions (grinding amount [t / H], classification rotational speed [rpm], ventilation rate [m ³ / min] within a range in which the vertical mill 20 can be operated in advance) The temperature distribution in the vertical mill, the height of the dam ring, etc.) are changed, and the particle size distribution of the mill fine powder and the content of valuable metals such as gold in the mill stone are measured. And based on a measurement result, the relationship between the operating conditions of the vertical mill 20, the particle size distribution of the mill fine powder sorted by the vertical mill 20, and the content of valuable metals in the mill waste is determined. .

  Based on this relationship, the particle size distribution of mill fines selected by the vertical mill 20 is that the valuable metals in the mill stones with respect to the content of valuable metals in the raw material waste under the predetermined operating conditions of the vertical mill 20 The content ratio of the first designated value ("first designated value" is a value expressed by the ratio of the content of valuable metals in the mill stone to the content of valuable metals in the raw material waste, for example, The ratio of the Cu content in the mill stone to the Cu content in the raw material waste is 10 times, the ratio of the Au content in the mill stone to the Au content in the raw material waste is 10 times, and the Ag content in the raw material waste The ratio of the Ag content in the mill stone with respect to the rate is 5 times, etc.) 90 [μm] residue by JIS sieve specified in JIS Z 8801 is 5 to 50 [mass%]. It will be The particle size distribution is adjusted. In addition, about the 1st designated value, based on the said relationship, it can select suitably in the numerical value within the range which can change the operating condition of the vertical mill 20. FIG.

  As the first specified value, instead of the ratio of the valuable metal content in the mill waste to the valuable metal content in the raw material waste, the value of the valuable metal in the mill waste relative to the valuable metal content in the mill fines Content ratio (for example, the ratio of the Cu content in the mill stones to the Cu content in the mill fines is 20 times, the ratio of the Au content in the mill stones to the Au content in the mill fines is 20 times, A ratio of the Ag content in the mill stone to the Ag content in the mill fine powder may be 10 times).

  Moreover, the particle size distribution of mill fine powder is not limited to this, and may be appropriately selected according to the first designated value. For example, a particle size distribution having an average particle size (D50) of a predetermined value or less is used. Also good.

  Note that the first designated value can be adjusted using the discharge amount of the mill waste stone relative to the input amount of the raw material waste as a guide. From the viewpoint of the content of valuable metals such as copper, gold and silver in the mill waste, or the recovery rate of valuable metals relative to the input of raw material waste, the amount of mill waste discharged relative to the input of raw material waste is 0 0.5 to 5 [%] is preferable, and 1 to 3 [%] is more preferable.

  As shown in FIG. 2, the vertical mill 20 includes a cylindrical main body portion 22, and a crushing portion 24 for crushing raw material waste is provided therein. A raw material supply path 26 extending in the vertical direction is provided on the side of the main body 22, and the raw material waste is supplied into the main body 22 through the raw material supply path 26.

  The crushing unit 24 is located at the bottom of the main body unit 22 and includes a table 28B that rotates around a vertical axis using an electric motor (not shown) as a drive source, and a plurality of crushing rollers 28A that roll on the upper surface. The raw material supplied into the main body 22 is supplied onto the table 28B, and is pulverized by the pulverizing roller 28A while rotating on the table 28B.

  An annular dam ring 29 having a certain thickness is provided on the peripheral edge of the table 28B. The dam ring 29 suppresses the vibration of the vertical mill 20 and controls the pulverization efficiency by forming a raw material powder layer having an appropriate thickness on the table 28B.

  A gas inlet 30 is provided on the bottom side surface of the main body 22, and a high-temperature gas (for example, 300 ° C.) is introduced into the main body 22 from the gas inlet 30. The introduced gas becomes a rising gas flow 32 in the main body 22, and the pulverized raw material powder is blown upward by the rising gas flow 32.

  A classifier 34 that performs shape selection is provided in the upper part of the main body 22. The classifier 34 classifies the powder carried by the rising gas flow 32 into fine powder and coarse powder using the principle of centrifugal separation. Fine powder having a predetermined particle size or less is discharged as a mill fine powder together with gas from the discharge port 36 at the top of the main body 22, and coarse powder exceeding the predetermined particle size is supplied to the pulverizing unit 24 for pulverization again. The

  An opening 38 for stone removal is provided around the table 28B. Relatively large coarse particles, lumps, high specific gravity and the like (including metals) that cannot get on the rising gas flow 32 fall over the dam ring 29 of the table 28B and fall into the opening 38. Coarse particles dropped into the opening 38 are conveyed to the outside by a belt conveyor (not shown) as mill waste.

  In the process of transporting the mill stone transported to the outside from the vertical mill 20, a sieving machine (not shown) may be provided as a collection device that selects and collects the mill stone in a predetermined particle size range from the mill stone. . By selecting and recovering mill waste in a predetermined particle size range with a recovery device, the ratio of the valuable metal content in the mill waste to the content of valuable metal in the raw material waste specified as the first specified value is greater than This is because the value is selected as the second specified value, and the valuable metal corresponding to the second specified value can recover the mill waste stone having a high content.

  The inventors changed the operating conditions in the range in which the vertical mill 20 can be operated in advance, and measured the content of valuable metals such as gold in the mill stone for each particle size range of the mill stone. Between the operating conditions of the mill 20, the particle size range of the mill waste stone, and the content rate of the valuable metal with respect to the particle size range of the mill waste stone, the content rate of the valuable metal in the mill waste stone as the particle diameter becomes smaller. The knowledge that there is a relationship of improving.

  Based on this relationship, the mill waste collected by the recovery device is screened, and the mill waste with respect to the valuable metal content in the raw material waste or mill fine powder, for example, under the predetermined operating conditions of the vertical mill 20 The ratio of the valuable metal content in the second designated value ("second designated value" is represented by the ratio of the valuable metal content in the mill stone to the valuable metal content in the raw material waste or mill fine powder, The value is larger than the first specified value. For example, the ratio of the Cu content in the mill waste to the Cu content in the raw material waste is 20 times, and the Au content in the mill waste relative to the Au content in the raw material waste The ratio is 20 times, the ratio of the Ag content in the mill stone to the Ag content in the raw material waste is 10 times, and the ratio of the Cu content in the mill stone is 40 times the Cu content in the mill fine powder The ratio of the Au content in the mill stone to the Au content in the mill fine powder is 40 times, and the ratio of the Ag content in the mill stone to the Ag content in the mill fine powder is 20 times.) In this way, the particle size of the mill stone is adjusted. For example, mill stones that preferably pass 10 [mm], more preferably mill stones that pass 5 [mm], are collected by a JIS sieve specified in JIS Z 8801.

  The valuable metal recovery system 1 according to this embodiment includes a dryer 10, magnetic separators 12, 12 ′, sieving machines 14, 14 ′, 14 ″, a pulverizer 16, and an eddy current selector 18. The pretreatment system is shown in Fig. 1. However, if the moisture concentration, particle size, etc. of the raw material waste meet the operating conditions of the vertical mill 20 capable of forming mill fine powder having a desired particle size distribution, The configuration of the processing system is not limited to this.

[Recovery method for valuable metals]
A method of recovering valuable metals such as gold from raw material waste containing valuable metals according to the present embodiment, particularly incineration ash which is municipal waste, will be described using the valuable metal recovery system of FIG.

  This method includes a pretreatment step for pretreating raw material waste containing valuable metals, and a raw waste material pretreated by the pretreatment step, which is pulverized to obtain a mill particle having a predetermined particle size distribution and a mill powder other than the mill powder. A pulverization step for sorting into mill stones and a recovery step for collecting mill stones with increased content of valuable metals are provided.

(Pretreatment process)
First, in order to reduce the moisture content of the raw material waste, the raw material waste is dried (drying step). This is because the waste is dried to form a raw material waste having a predetermined moisture concentration that meets the operating conditions of the vertical mill 20. In addition, by drying the raw material waste, the sorting in the magnetic separators 12 and 12 ', the sieving machines 14, 14' and 14 ", and the eddy current separator 18 is facilitated.

  In addition, when the moisture content of the waste meets the operating conditions of the vertical mill 20 that can form mill fine powder having a desired particle size distribution, it is not always necessary to provide the drying step in the preliminary treatment step.

  Next, the raw material waste dried in the drying step is separated from the waste by using a magnetic separator 12 from a magnetic metal such as iron (first magnetic separation step). When the raw material waste supplied to the vertical mill 20 contains a magnetic metal such as iron (for example, iron scraps), the stable operation of the vertical mill 20 becomes difficult and the recovered mill waste This is because the content of valuable metals in the stone may be reduced.

  Next, the raw material waste from which the magnetic metal such as iron is sorted and removed from the waste by the first magnetic sorting process is separated from the sieving machine 14 into a waste having a predetermined particle size or less and a particle size exceeding the predetermined particle size. After sorting into waste, the waste having a particle size exceeding a predetermined particle size is coarsely pulverized. Then, the coarsely pulverized waste is supplied into the waste having a predetermined particle size or less selected by the sieving machine 14, and the waste having the predetermined particle diameter or less is discharged from the sieving machine 14 'and the particles exceeding the predetermined particle size. Sort into diameter waste (coarse grinding process).

  This is because the waste having a particle size of a predetermined particle size or more is selected and removed from the process to meet the operating conditions of the vertical mill 20 that can form mill fine powder having a desired particle size distribution. Accordingly, when the particle size distribution of the waste meets the operating conditions of the vertical mill 20 that can form mill fine powder having a desired particle size distribution, it is not always necessary to provide the coarse pulverization step in the pretreatment step.

  As shown in FIG. 1, in this embodiment, in the coarse pulverization step, waste having a particle size exceeding the predetermined particle size selected and removed by the sieving machine 14 'is recovered as a nonmagnetic metal for convenience. .

  Next, the raw material waste having a predetermined particle size or less coarsely pulverized in the coarse pulverization step is selected from the magnetic metal such as iron by the magnetic separator 12 '(second magnetic separation step). Magnetic metal such as iron can be efficiently recovered from waste roughly pulverized by the coarse pulverization step. As shown in FIG. 1, in the present embodiment, wastes such as iron scraps collected by the first magnetic sorting process and the second magnetic sorting process are collected as magnetic metals.

  In addition, in the second magnetic separation process, the magnetic metal having a predetermined particle size or less is collected in the vertical mill 20 with respect to the magnetic metal such as iron selected from the waste, and the raw material is not the magnetic metal attached to the magnetic metal. The quantity of waste may be increased.

  Next, the eddy current sorter 18 sorts aluminum from the raw material waste from which the magnetic metal has been sorted and removed by the second magnetic sorting process (eddy current sorting process). Aluminum selected by the eddy current selection process is recovered as a nonmagnetic metal. The raw material waste from which the aluminum has been sorted and removed by the eddy current sorting step is supplied to the vertical mill 20. In addition, it is not always necessary to provide the eddy current selection step in the preliminary processing step, and an eddy current selection step may be provided as a step after the crushing step described later.

  As described above, the raw material waste pretreated by the pretreatment process of the present embodiment is easy to handle because it is a powder having a low water content, and is previously blended with other raw materials such as limestone to form a cement raw material. Then, it may be used for the pulverization step.

  As described above, in the pretreatment process of the present embodiment, the mill fine powder having the desired particle size distribution is formed by the drying process, the first magnetic field selection process, the second magnetic field selection process, the coarse pulverization process, and the eddy current selection process. Pretreatment was carried out so as to obtain raw material waste adapted to the operating conditions of the obtained vertical mill 20. However, if the moisture content, particle size, etc. of the raw material waste meet the operating conditions of the vertical mill 20 capable of forming mill fine powder having a desired particle size distribution, the order of each step can be selected as appropriate, The configuration of the pretreatment process is not limited to this.

(Crushing process)
Next, the mill waste having a predetermined particle size distribution obtained as a result of pulverizing the raw material waste pretreated in the pretreatment step using the vertical mill 20, and an upper limit value of the predetermined particle size distribution To mill stone containing coarse powder having a larger particle size than that (grinding step).

  Mill fine powder is useful as a raw material for cement. In the present embodiment, magnetic stainless steel is separated in the first magnetic separation process and the second magnetic separation process, and nonmagnetic stainless steel is also separated as mill waste in the pulverization process. A cement raw material with a reduced Cr content capable of producing valent chromium can be obtained.

(Recovery process)
And the mill waste stone which raised the content rate of valuable metals, especially copper, zinc, silver, and gold | metal | money is collect | recovered (collection process). In raw material waste, the content of valuable metals such as gold is low and the fluctuation of the content is large, but the raw material is recovered by collecting mill waste stones with increased content of valuable metals such as gold in the mill waste stones. Valuable metals such as gold in the waste can be efficiently recovered and used as a smelting raw material.

  The mill stone may be further subjected to a magnetic force sorting step and eddy current sorting (not shown) to increase the content of copper, zinc, silver, and gold. In particular, in the magnetic sorting, non-magnetic stainless steel tends to become magnetized by deformation by the impact of the vertical mill 20, and by removing the stainless steel, copper, zinc, silver in the mill waste stone is removed. And the content rate of gold can be increased.

  If the content of copper, zinc, silver, and gold in the mill waste stone does not reach the desired value, the raw mill waste 20 is again used as raw material waste or pretreated raw material waste. Input and pulverize with raw material waste.

  Hereinafter, the Example which implemented the valuable metal recovery method with respect to the municipal waste incineration ash which is a raw material waste using the valuable metal recovery system of FIG. 1 is described.

  In the pretreatment system, a commercially available dryer, magnetic separator, eddy current separator, coarse pulverizer, and sieving machine were used. Further, a table having a table diameter of 1800 [mm] and three grinding rollers having an average roller diameter of 1120 [mm] capable of forming mill fine powder having a 90 [μm] residue of 5 to 50 [mass%] by a JIS sieve. A vertical mill provided with

  The raw material waste was dried to 5 wt% or less by a dryer. The raw material waste was preliminarily pulverized with a coarse pulverizer so that the maximum particle size was 20 [mm] or less after the magnetic metal was previously removed by a magnetic separator. Those that were not coarsely pulverized to a particle size of 20 [mm] or less and those that were eddy current-selected without being subjected to magnetic force selection even when the particle size was 20 [mm] or less were recovered as nonmagnetic metals.

  Further, iron or the like exceeding 5 [mm] was collected as a magnetic metal by a sieving machine for those that were not subjected to eddy current selection due to magnetic selection. And the raw material waste from which the magnetic metal and the nonmagnetic metal were selectively removed was supplied to the vertical mill.

The operating conditions of the vertical mill were a grinding amount of 14 to 22 [t / H], a classifier rotation speed of 700 to 730 [rpm], and a hot air flow rate of 1000 to 1200 [m ³ / min].

  Tables 1 and 2 show the results of carrying out the valuable metal recovery method using the valuable metal recovery system under the above operating conditions. In addition, the content rate of each metal is an anhydrous base, and is measured about each metal element (Fe: JISM 8212, Al: JIS M 8220, Cu: JIS M8121, Zn: JIS M8124, Au and Ag: JIS M 8111).

  Table 1 shows the content of metals (iron, aluminum, copper, zinc, gold, silver) in mill stone obtained by operating the valuable metal recovery system for 1 day or 3 days. In addition, about silicon, calcium, etc., it did not describe in Table 1. Table 2 shows the metal content of the nonmagnetic metal, magnetic metal, mill stone, and mill fine powder obtained in Example 6. The metal content of the incinerated ash was calculated from the metal content of non-magnetic metal, magnetic metal, mill stone, and mill fine powder (90 [μm] residue 33 [mass%]). .

  Table 3 shows the metal distribution in Example 6. Furthermore, about 3 [kg] of the milled stone obtained in Example 6 and Example 7 was collected, sieved for each particle size, and 20 Nd in a 20 [cm] cylindrical container with a neodymium bar magnet. Magnetic sorting was performed for a minute. Table 4 shows the metal content of the magnetic material and the nonmagnetic material for each particle group classified by the particle size obtained as a result. In Table 4, the magnetic material and non-magnetic material expressed by weight% show values obtained by rounding off one decimal place.

  As shown in Table 1, in mill stone, the content of copper and zinc is 2 to 10 times that of general natural ore, and the content of gold and silver is 10 times. That's it. Furthermore, as shown in Table 2, the content of copper, zinc, gold, and silver in the milled stone is 10 times or more that of incinerated ash, and in particular, the content of gold and silver in the milled stone [g / It can be seen that t] is significantly higher. Further, as shown in Table 3, it can be seen that the recovery rate of gold is particularly high and the recovery rates of copper, zinc, and silver are also high.

  Therefore, the content of valuable metals such as gold in the raw material waste is very low and the fluctuation of the content is large, but the content of valuable metals such as gold in the mill stone is remarkably increased, copper, zinc, It turns out that mill waste stone is useful as a raw material for smelting gold and silver. In addition, by collecting mill waste stone, valuable metals such as gold in the waste that have not been collected can be efficiently collected, which can greatly contribute to resource recycling.

  Further, as shown in Table 4, it can be seen that by selecting mill stones having a fine particle size, the content of copper, zinc, gold, and silver in the mill stones increases. Moreover, it turns out that the content rate in the mill stone of copper, zinc, gold | metal | money, and silver becomes high by collect | recovering nonmagnetic substances from mill stone.

  DESCRIPTION OF SYMBOLS 1 ... Valuable metal recovery system 1, 10 ... Dryer, 12, 12 '... Magnetic separator, 14, 14', 14 "... Sieving machine, 16 ... Crusher, 18 ... Eddy current sorter 18, 20 ... Vertical type Roller mill (vertical mill), 22 ... body part, 24 ... grinding part, 26 ... raw material supply path, 28A ... grinding roller, 28B ... table, 29 ... dam ring, 30 ... gas inlet, 32 ... rising gas flow, 34: classifier, 36: outlet, 38 ... opening.

Claims (6)

A pretreatment process for pretreating raw material waste containing valuable metals;
Milling the raw material waste pretreated by the pretreatment step, mill fine powder having a predetermined particle size distribution obtained as a result of the grinding, and a particle size distribution on the larger diameter side than the predetermined particle size distribution A step of selecting mill waste containing coarse powder having the raw material waste or the mill by performing the pulverization and the selection so as to adjust the predetermined particle size distribution of the mill fine powder. A crushing step of adjusting the ratio of the content of valuable metals in the mill stone to the content of valuable metals in the fine powder so as to be equal to or higher than the first specified value;
A recovery step of recovering the mill waste stone,
The pretreatment step is a valuable metal recovery method including at least a magnetic separation step of performing magnetic separation on the raw material waste . The valuable metal recovery method according to claim 1,
The recovery step is a part of the mill waste stone, wherein a ratio of a valuable metal content rate in the mill waste stone to a valuable metal content rate in the raw material waste is higher than the first designated value. A valuable metal recovery method for recovering the mill stone containing a particle size in a predetermined particle size range equal to or greater than a value. In the valuable metal recovery method according to claim 1 or 2,
The method for recovering valuable metals, wherein the raw material waste is municipal waste incineration ash. In the valuable metal collection | recovery method as described in any one of Claims 1-3,
The valuable metal recovery method, wherein the valuable metal is at least one of gold and silver. A pretreatment system for pretreating raw material waste containing valuable metals;
The raw material waste prepared by the pretreatment system is pulverized, the mill fine powder having a predetermined particle size distribution obtained as a result of the pulverization, and a particle size distribution on the larger diameter side than the predetermined particle size distribution The mill waste containing coarse powder is sorted and the pulverization and the sorting are performed so as to adjust the predetermined particle size distribution of the mill fine powder. A vertical mill that adjusts the ratio of the content of valuable metal in the mill stone to the content of metal to be equal to or higher than the first specified value,
The pretreatment system is a valuable metal recovery system including a magnetic separator for performing magnetic separation on at least the raw material waste . In the valuable metal recovery system according to claim 5,
A predetermined part of the mill waste stone, wherein a ratio of a valuable metal content rate in the mill waste stone to a valuable metal content rate in the raw material waste is equal to or higher than a second designated value higher than the first designated value. A valuable metal recovery system including a recovery device for recovering the mill waste stone having a particle size in a particle size range.

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