JP5857572B2 - Valuable metal recovery method - Google Patents

Description

  The present invention relates to a method for recovering valuable metals contained in a metal composite for recycling, such as a waste battery such as a lithium ion battery.

  Lithium-ion batteries and other batteries that are used or defective in the process (hereinafter referred to as waste batteries) are recycled, and treatment methods for collecting valuable metals contained in waste batteries are roughly divided into dry methods. There are wet methods.

  In the dry method, crushed waste batteries are melted, and valuable metals to be recovered and other metals with low added value are separated and recovered using the difference in oxygen affinity between them. . That is, an element with low added value such as iron is oxidized as much as possible to obtain slag, and valuable materials such as cobalt are collected as an alloy while suppressing oxidation as much as possible. Then, the alloy recovered by the dry method is made into a solution by adding, for example, an acid, and separated by solvent extraction, neutralization, etc., as is done by existing metal refining, and wet, such as electrowinning or gas reduction. By the method, valuable metals are recovered as high-purity metals or metal salts.

  For example, Patent Document 1 discloses a method capable of recovering about 80% of valuable metals such as nickel and cobalt by using a high-temperature heating furnace, adding flux to a waste battery, and repeating slag separation. Yes.

  However, when waste batteries are oxidized in the melting process in the dry process, there are many substances to be oxidized, and there is a large variation among the processing batches. It is difficult to obtain and valuable metals cannot be recovered stably.

  Therefore, as a means for increasing the recovery rate, by oxidizing the waste battery etc. prior to the melting step, oxidation is performed in advance so that optimum oxidation proceeds for each of various metals contained in the waste battery etc. Processing may be performed.

  For this oxidation treatment by roasting, for example, a tunnel kiln can be suitably used. In a tunnel kiln, waste batteries and the like are placed in a roasting container and subjected to oxidation treatment while roasting in a tunnel-type furnace. At this time, iron in the exterior such as a waste battery may adhere to the roasting container due to the oxidation treatment at a high temperature. Then, a step of peeling off the attached waste battery, etc., a step of washing the iron oxide remaining on the container surface with a strong acid is separately required, and there are many cases where it is necessary to dispose and replace the roasting container, There has been a problem of increased processing costs.

  As a method for preventing adhesion between a roasting container and a metal composite that is an object of oxidation treatment by roasting, for example, Patent Document 2 discloses a reducing agent containing 80 wt% or more of solid carbon on a moving bed of a tunnel kiln. Is disclosed, and a metal composite containing a valuable metal is placed thereon.

US Pat. No. 7,169,206 JP 2011-94206 A

  However, when the reducing agent is loaded on the moving bed as in the method described in Patent Document 2, the reduction reaction gradually proceeds even in the oxidation step, and the efficiency of the target oxidation treatment is reduced. In particular, when recovering valuable metals such as cobalt from waste batteries, it is necessary to oxidize and remove iron, and to separate the excess reducing agent before separating it from the cobalt-containing alloy. Therefore, the processing efficiency of the entire process is not improved, and there is a problem that the cost increases together with the cost of the reducing agent itself.

  The present invention has been made in order to solve the above-mentioned problems, and in the process of recovering valuable metals, the processing efficiency of the oxidation treatment of the metal composite by roasting is increased, and the additive necessary for the entire process is added. An object of the present invention is to provide a valuable metal recovery method capable of reducing the processing cost as compared with the conventional method by reducing the total amount.

  The inventors lower the melting point of the metal composite on the loading surface of the baking container on which the metal composite is placed when the metal composite such as a waste battery is fired and oxidized. It is possible to prevent adhesion of the metal composite to the container at the time of roasting by loading the particulate anti-adhesive agent having an effect, and furthermore, the granular material used for anti-adhesion in the melting process performed after the oxidation process. It has been found that by using a process that uses an adhesion inhibitor as a flux, the processing efficiency of the entire valuable metal recovery process can be improved and the cost can be reduced, and the present invention has been completed. More specifically, the present invention provides the following.

  (1) A method for recovering valuable metal from a metal composite containing a valuable metal, the method comprising roasting and oxidizing the metal composite, and melting and melting the metal composite that has undergone the oxidation process. A melting step for obtaining a product, and a slag separation step for separating a slag from the melt and recovering an alloy containing a valuable metal, wherein the oxidation step is performed on a loading surface of a roasting container. In the state where the particulate composite containing an anti-adhesive agent is loaded and the metallic composite is placed on the particulate anti-sticking agent, the metallic composite is roasted and oxidized, and the melting step includes the step of The same fusion furnace in which the metal composite oxidized through the oxidation step and a part or all of the granular adhesion inhibitor loaded on the loading surface of the roasting container in the oxidation step Valuable metal recovery process, which is the process of melting the metal .

  (2) The valuable metal recovery method according to (1), wherein the roasting container is a ceramic container.

  (3) The valuable metal recovery method according to (1) or (2), wherein the particulate adhesion inhibitor is a particulate mixture containing silicon dioxide and / or lime.

(4) The granular adhesion inhibitor is a mixture of silicon dioxide and lime, and the weight ratio (SiO ₂ / CaO) of silicon dioxide (SiO ₂ ) and lime (CaO) in the granular adhesion inhibitor is 0.5 or more. The valuable metal recovery method according to any one of (1) to (3), which is 1.5 or less.

  (5) The valuable metal recovery method according to any one of (1) to (4), wherein in the oxidation step, an oxidation treatment is performed in which the metal composite is roasted and oxidized at a temperature of 1000 ° C. to 1300 ° C. .

  (6) The valuable metal recovery method according to any one of (1) to (5), wherein the oxidation step is performed using a tunnel kiln.

  (7) The valuable metal recovery method according to any one of (1) to (6), wherein the metal composite is a lithium ion battery.

  According to the valuable metal recovery method of the present invention, the oxidized metal composite is prevented from adhering to the roasting container in the valuable metal recovery process including the oxidation step by roasting of the metal composite and the subsequent melting step. As a result, the processing efficiency of the oxidation step can be increased, and the cost of the valuable metal recovery process as a whole can be reduced.

It is a flowchart which shows the valuable metal collection | recovery method from a waste battery which is one Example of the valuable metal collection | recovery method of this invention. It is a schematic diagram which shows the use condition of the tunnel kiln used for the oxidation process in the valuable metal recovery method of this invention. It is a schematic diagram which shows the state by which the waste battery is loaded on the container for roasting in the oxidation process in the valuable metal collection | recovery method of this invention.

  Hereinafter, an embodiment of the valuable metal recovery method of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart showing an example of a method for recovering valuable metals from a metal complex such as a waste battery containing valuable metals. The type of waste battery is not particularly limited, but a rare metal such as cobalt or lithium can be recovered, and its use has been expanded to automobile batteries, etc., and a lithium ion battery that requires a large-scale recovery process is the present invention. It can illustrate preferably as a process target. In this embodiment, although the case where the metal composite containing a valuable metal is a lithium ion battery will be described, the present invention is not limited to this.

<Overall process>
As shown in FIG. 1, this valuable metal recovery method includes an oxidation step ST20, a dry step S20, and a wet step S30. Moreover, the baking process ST10 may further be provided prior to the oxidation process ST20. The valuable metal recovery method in this embodiment is a total process in which an alloy is obtained in the dry process S20, and then the valuable metal element is separated and recovered in the wet process S30. In addition, the metal composite in the present invention only needs to contain a metal such as a waste battery in the object to be treated, and does not exclude the addition of other metals or resins other than the waste battery as appropriate. In that case, it is the metal composite of the present invention including other metals and resins.

<Oxidation step ST20>
First, the details of the oxidation step ST20, which is a feature of the present invention, will be described with reference to FIGS. FIG. 2 is a schematic diagram illustrating a use state of the tunnel kiln 1 used in the oxidation step ST20, and FIG. 3 is a schematic diagram illustrating a state in which the waste battery 30 is loaded on the roasting container 20 in the oxidation step ST20. It is. The oxidation step ST20 in the present invention is a step of oxidizing the waste battery 30 by roasting the waste battery 30 containing valuable metals in the roasting furnace of the tunnel kiln 1. About the oxidation degree of the waste battery 30 in oxidation process ST20, in slag separation ST22 and alloy separation ST23 which are subsequent processes, it is calculated | required to adjust to a preferable range in order to raise the recovery rate of a valuable metal. As the roasting furnace, a heating furnace capable of roasting waste batteries at a temperature within a predetermined range can be used without any particular limitation, but the degree of oxidation can be adjusted by individual and strict control of the heating temperature and processing time. A tunnel kiln 1 that is easy can be used particularly preferably. Hereinafter, the case where oxidation process ST20 is performed using the tunnel kiln 1 is demonstrated as one Embodiment of this invention.

  In the oxidation step ST20, the main elements constituting the material of the waste battery 30 are generally oxidized in the order of aluminum> lithium> carbon> manganese> phosphorous> iron> cobalt> nickel> copper due to the difference in affinity with oxygen. It will be done. That is, aluminum is most easily oxidized and copper is most hardly oxidized. In order to improve the recovery rate of cobalt, nickel, and copper, which have a relatively low affinity with oxygen, in the oxidation step ST20, while increasing the iron oxidation degree for iron and cobalt that are close to each other in the affinity with oxygen, At the same time, it is required to strictly adjust the degree of oxidation to suppress cobalt oxidation.

  In the oxidation step ST20, oxidation treatment is performed by supplying oxygen while roasting the waste battery at a temperature of 1000 ° C. to 1300 ° C. In the conventional valuable metal recovery method, the oxidation process is performed in the melting process ST21 in the dry process S20. However, the oxidation process ST20 is provided before the melting process ST21, and the oxidation process by roasting is performed in advance. There is an advantage that the degree of oxidation can be controlled more strictly by adjusting the time and temperature. Carbon, which often impairs the stability of the overall oxidation treatment, can be easily controlled for oxidation unlike the case where the oxidation treatment is performed in the melting step in the dry process. Specifically, in this oxidation step ST20, the oxidation treatment is performed to such an extent that almost all the carbon is oxidized. Thereby, the dispersion | variation by the non-oxidation of the carbon in melting process ST21 of the next process can be suppressed, and the oxidation degree of iron or cobalt can be adjusted more strictly.

  This oxidation step ST20 is performed at a stage before the melting step ST21 is performed in the dry step S20, and is performed in the tunnel kiln 1 in this embodiment. In the weight ratio of the constituent materials of the lithium ion battery, iron accounts for approximately 20%, cobalt accounts for approximately 20%, carbon accounts for 25%, and aluminum accounts for approximately 5%. Of these, in the oxidation step ST20, the carbon in the waste battery 30 is completely oxidized and burned, and the oxidation treatment corresponding to the state in which about 70% of the total amount of aluminum and iron are oxidized is performed with the optimum oxidation degree. . As oxidation progresses to the point where the total amount of iron is oxidized, when the oxidized waste battery 30 is melted at about 1500 ° C., the amount of rare metals such as cobalt to be recovered increases in the slag, and the recovery rate decreases. It is not preferable. On the other hand, if the oxidation degree of iron is small, it is not preferable because much iron that should be distributed to the slag side remains in the alloy recovered after melting.

  If the roasting temperature in the oxidation step ST20 is less than 1000 ° C., the time required for obtaining the above-mentioned optimum degree of oxidation is undesirably long. For example, if the oxidation treatment is performed in a pure oxygen atmosphere at a temperature slightly exceeding 1000 ° C., the necessary oxidation treatment is completed in about 1 hour, but if the oxidation step ST20 is performed in the same atmosphere at 900 ° C., the time is 4 hours or more. It becomes. On the other hand, when the temperature in the kiln main body 11 exceeds 1300 ° C., the copper foil that is the battery constituent material is completely melted and hinders smooth operation, or the roasting container 20 and the kiln main body 11 deteriorate. It may be connected, which is not preferable. For this reason, it is preferable that the roasting temperature in oxidation process ST20 is 1000 degreeC or more and 1300 degrees C or less.

  The oxidation treatment time in the oxidation step is qualitatively higher in oxygen concentration, and the higher the oxidation temperature, the shorter the time required to obtain the optimum degree of oxidation. For example, if the oxidation time is set to about 1 hour, 1100 ° C. or higher is required in an oxygen 100% atmosphere, and approximately 1200 ° C. is required in an air atmosphere. Since the target oxidation time varies depending on the allowable amount of capital investment and the required processing capacity, the oxygen concentration in the atmosphere and the oxidation temperature may be controlled accordingly.

  In this oxidation step ST20, a heating furnace capable of performing oxidation treatment inside the waste battery by supplying oxygen while roasting the waste battery in the above temperature range can be used without any particular limitation. As can be seen, the tunnel kiln 1 can be suitably used.

  As shown in FIG. 2, the tunnel kiln 1 is a heating furnace including at least a kiln main body 11, a conveying means 12, and a burner 13. The kiln body 11 is a tunnel-shaped tubular structure made of a structural material such as refractory brick having heat resistance. The transport means 12 is, for example, a metal belt conveyor or the like, and may have any function that can transport the waste battery 30 in the kiln main body 11 that is at a high temperature. The burner 13 is, for example, a gas burner, an electrothermal burner, or the like, as long as it can be heated in the furnace at a required temperature required for the oxidation treatment. Specifically, it is sufficient if heating at about 1000 ° C. to 1300 ° C. is possible.

  In the tunnel kiln 1, the waste battery 30 is carried in the direction A from the carry-in port 14 while being placed on the roasting container 20. Then, the waste battery 30 is roasted by the heat supplied from the burner 13 while passing through the inside of the kiln main body 11 by the conveying means 12 and subjected to an oxidation treatment. The heating temperature is preferably 1000 ° C to 1300 ° C. The waste battery 30 subjected to the oxidation treatment by roasting is discharged from the discharge port 15 in the direction B, and is put into a melting furnace in which a subsequent melting step ST21 is performed.

  As shown in FIGS. 2 and 3, in the oxidation step ST <b> 20 of the present invention, the waste battery 30 is carried into the kiln main body 11 while being placed on the stacking surface 21 of the roasting container 20. At that time, as shown in FIG. 3, first, the particulate adhesion preventing agent 40 is loaded on the loading surface 21 of the roasting container 20, and the waste battery 30 is placed on the loaded particulate adhesion preventing agent 40, thereby disposing the waste. Roasting is performed with the battery 30 not in direct contact with the loading surface 21.

  The roasting container 20 can be a mortar, which is a box-shaped container, or a plate-shaped container called a setter, all of which are heat-resistant to heat loads up to about 1300 ° C. And a container made of ceramics such as mullite or alumina can be preferably used.

When the series of oxidation steps is completed, the roasting container 20 is taken out and reused. At this time, there is a problem that the processing efficiency of the valuable metal recovery process is reduced due to the adhesion of the oxidized iron oxide and the roasting container 20 of the waste battery 30. In particular, when the roasting container 20 is made of an oxide containing silicon dioxide (SiO ₂ ), this problem is remarkable. However, in the valuable metal recovery method of the present invention, as described above, in the oxidation step ST20. At the time of roasting, the particulate adhesion preventing agent 40 is loaded on the loading surface 21 of the roasting container 20, thereby preventing the above adhesion and solving this problem. Further, the amount of additive required in the entire process is reduced by introducing the particulate adhesion preventing agent 40 as it is into the next melting step ST21. As described above, the present invention is characterized in that the processing efficiency is improved and the cost is reduced in the entire process of recovering valuable metals.

The particulate adhesion preventing agent 40 contains a flux having an effect of lowering the melting point when the waste battery 30 is melted in the melting step ST21 which is the next step, and the roasting temperature, specifically about 1500 ° C. Any material that is stable at the following temperatures may be used. For example, silicon dioxide (SiO ₂ ), lime (CaO), or a mixture containing them, which is often used as a flux, can be preferably used as the particulate adhesion preventing agent 40.

When the particulate adhesion preventing agent 40 is a mixture of silicon dioxide and lime, the weight ratio (SiO ₂ / CaO) of silicon dioxide (SiO ₂ ) and lime (CaO) in the particulate adhesion preventing agent is 0.5 or more and 1. The range is preferably 5 or less, more preferably 0.8 or more and 1.4 or less. If the mass ratio is less than 0.5, it is not preferable because the melting temperature of the slag in the subsequent melting step ST21 cannot be sufficiently lowered, and if the mass ratio exceeds 1.5, the viscosity of the molten slag is high. This is not preferable because it becomes too difficult to separate from the alloy.

  If the required amount of flux in the melting step ST21 is small and less than the load capacity to prevent seizure between the waste battery 30 and the roasting container 20, the oxidation step ST20 is performed like sand, for example. A mixture of substances that are stable to the roasting temperature at the time and that are not distributed to the alloy in the alloy separation ST23 can also be used as the particulate adhesion preventing agent 40.

  Regarding the loading amount of the particulate adhesion preventing agent 40 on the roasting container 20, the thickness of the layer made of the particulate adhesion preventing agent 40 at the time of loading is preferably 0.2 mm or more. If the thickness is 0.2 mm or more, the flux is stable in the roasting temperature range, so that the sticking of the waste battery 30 and the roasting container 20 due to seizure can be sufficiently prevented. Further, as the upper limit of the loading capacity, it is preferable to load each unit container with the upper limit as the quantity required in the subsequent melting step ST21. When the required amount of flux in the melting step ST21 is small, a part of the particulate adhesion preventing agent 40 that has undergone the oxidation step ST20 may be repeatedly used in the oxidation step ST20 before entering the melting step ST21.

  As described above, the waste battery 30 placed on the particulate adhesion preventing agent 40 loaded on the roasting container 20 is roasted at the roasting temperature described above, and the kiln main body 11 is moved by the conveying means 12. Move. At this time, an oxidizing agent such as air is introduced into the kiln main body 11 in order to adjust the oxidation degree of the waste battery 30 and improve the recovery rate of nickel, cobalt, and copper. For example, aluminum foil is used as a positive electrode material for lithium ion batteries. Carbon is used as the negative electrode material. Furthermore, the outer shell of the battery is made of iron or aluminum. These materials basically act as a reducing agent. For this reason, the total reaction for converting these materials into gas or slag is an oxidation reaction. Therefore, it is necessary to introduce oxygen into the kiln body 11. This is why air is introduced in the oxidation step ST20.

  Although the oxidizing agent is not particularly limited, a gas containing oxygen such as air, pure oxygen, and oxygen-enriched gas is preferably used from the viewpoint of easy handling. These are fed directly into the kiln body 11 in the oxidation step ST20. The introduction amount of the oxidizing agent is about 1.2 times the chemical equivalent required for the oxidation of each substance to be oxidized.

  As described above, by performing oxidation step ST20 prior to melting step ST21, it is possible to adjust the degree of oxidation more strictly than in the case of performing in melting step ST21. This makes it possible to stably increase the recovery rate of valuable metals from waste batteries.

  After the completion of the oxidation step ST20, part or all of the particulate adhesion inhibitor 40 loaded on the loading surface 21 of the roasting container 20 is put together with the waste battery 30 into a melting furnace that performs the melting process in the melting step ST21. The For example, by tilting the waste battery 30 oxidized in the oxidation step ST20 together with the roasting container 20, the waste battery 30 falls as it is without adhering to the roasting container 20, and the melting process in the melting step ST21 is performed. It can be easily put into a melting furnace. At this time, the particulate adhesion preventing agent 40 containing the flux loaded at the same time falls in the melting furnace in the same manner, and the required flux can be efficiently fed. For this reason, the processing efficiency of the whole process can be improved, reducing the quantity of the additive required in the whole process.

<Roasting process ST10>
In the valuable metal recovery method of the present invention, the roasting step ST10 may be provided prior to the oxidation step ST20. The roasting step ST10 is a pretreatment step performed prior to other steps in the valuable metal recovery method, and the waste battery 30 is roasted at a temperature of 300 ° C. to 600 ° C. It is a process to reduce the organic carbon derived from. The roasting time is not particularly limited, but it is preferable to adjust so that the organic-derived carbon after the roasting step ST10 is 10% by mass or less with respect to the organic-derived carbon before the roasting step ST10. Thereby, the variation in the oxidation degree in the subsequent oxidation treatment can be suppressed.

  In the valuable metal recovery method of the present invention, when the roasting step ST10 is performed prior to the oxidation step ST20, the particulate adhesion preventing agent 40 is previously loaded on the loading surface 21 of the roasting container 20 and loaded. The roasting step ST10 is performed in a state where the waste battery 30 is placed on the granular adhesion preventing agent 40, and then the oxidation step ST20 while the state where the waste battery 30 is placed on the granular adhesion preventing agent 40 is maintained. It can be performed. Also by doing so, it is possible to prevent the waste battery 30 from adhering to the roasting container 20 in the oxidation step ST20 and to reduce the total amount of additives required in the entire process.

  The roasting step ST10 and the oxidation step ST20 have the above-mentioned effects by being sequentially performed in separate furnaces prepared for the respective steps, but both steps are performed in a single furnace. It is also possible to carry out continuously. For example, by providing a temperature zone of 300 ° C. to 600 ° C. and a temperature zone of 1000 ° C. to 1300 ° C. (not shown) in a single tunnel kiln 1, a roasting process ST10 and an oxidation process ST20 are united. It can carry out continuously in the heating furnace.

  Alternatively, the furnace inside the tunnel kiln 1 is heated to 300 ° C. to 600 ° C. to perform the roasting step ST10, and then the furnace is heated to 1000 ° C. to 1300 ° C. to perform the oxidation step ST20. It is also possible to perform both processes continuously as a batch process in a single tunnel kiln 1.

  As described above, by continuously performing the roasting step ST10 and the oxidation step ST20 in a single heating furnace, while maintaining the recovery rate of valuable metals similar to the case of sequentially performing in a separate furnace. Costs can be reduced by reducing equipment and processes.

In addition, although the roasting process ST10 was mentioned as an example of the preliminary | backup process performed previously, loading of the granular adhesion inhibitor 40 to the container 20 for roasting is not necessarily restricted just before oxidation process ST20, The said As long as it is the aspect which can perform oxidation process ST20 in the state which mounted the waste battery 30 on the granular adhesion inhibitor 40 as demonstrated, it pre-roasts in all the preliminary processes performed before oxidation process ST20. Even when the particulate adhesion preventing agent 40 is loaded on the container 20, it is within the scope of the present invention.
<Dry process S20>
In the dry process S20, a melting process ST21 for melting the waste battery 30 oxidized in the oxidation process ST20 at a melting temperature of about 1500 ° C. to 1650 ° C. is performed. Melting process ST21 can be performed with a conventionally known electric furnace or the like.

  In the valuable metal recovery method of the present invention, since the oxidation process is performed in advance in the oxidation step ST20, it is not necessary to perform the oxidation process on the waste battery melted in the dry process as in the prior art.

  However, when the oxidation in the oxidation step ST20 is insufficient or when the degree of oxidation needs to be adjusted, an additional oxidation step for performing additional oxidation treatment for a very short time can be provided in the melting step ST21. This additional oxidation step makes it possible to control the degree of oxidation more finely. In addition, the additional oxidation process can be performed in a very short time compared to the conventional oxidation process at the time of melting, so there is little adverse effect on work efficiency, and there is also a problem of cost increase because less lance consumption is required. Hard to occur.

In the melting step ST21, it is desirable to add SiO ₂ (silicon dioxide), CaO (lime) or the like as a flux in order to lower the melting point of the slag separated in the slag separation ST22 described later. In the valuable metal recovery method of the present invention, as described above, in the preceding oxidation step ST20, the granular adhesion inhibitor 40 containing the flux used for preventing adhesion of the roasting container 20 and the waste battery 30 is used. The melting point of the slag can be lowered by putting it in a melting furnace that performs the melting step ST21 as it is.

By the melting step ST21, slag, which is an oxide such as iron or aluminum, and alloys of nickel, cobalt, and copper, which are valuable metals, are generated. Since they have different specific gravities, they are recovered by slag separation ST22 and alloy separation ST23, respectively. At this time, if the content of aluminum oxide in the slag is relatively large, a slag having a high melting point and a high viscosity is obtained. However, as described above, SiO ₂ and CaO are added to lower the melting point of the slag in the melting step ST21. Therefore, the viscosity can be reduced by lowering the melting point of the slag. For this reason, slag separation ST22 can be performed efficiently. Note that dust, exhaust gas, and the like in the melting step ST21 are detoxified in a conventionally known exhaust gas treatment ST24.

  The melting step ST21 is a process in which a plurality of melting steps are repeated, and the degree of oxidation is controlled by adjusting processing conditions such as the melting temperature in each step so that individual metals are separated step by step. You can also For example, after the first melting process, nickel, cobalt, and copper as valuable metals are separated from the first alloy containing iron that is not a valuable metal, and then iron is separated to the slag side in the second melting process. In addition, the recovery rate of the valuable metal can be increased by recovering the valuable metal nickel, cobalt, and the second alloy containing copper.

After the alloy separation ST23, a dephosphorization step ST25 is further performed on the obtained alloy. In lithium ion batteries, ethylene carbonate, diethyl carbonate, or the like is used as an organic solvent, and LiPF ₆ (lithium hexafluorophosphate) or the like is used as an electrolyte as an electrolyte. Although phosphorus in this LiPF ₆ has the property of being relatively easily oxidized, it has a property of relatively high affinity with iron group elements such as iron, cobalt and nickel. The phosphorus in the alloy is difficult to remove in the subsequent wet process S30 in which each element is recovered as a metal from the alloy obtained in the dry process S20, and accumulates as impurities in the processing system, so that the operation cannot be continued. For this reason, it is removed in this dephosphorization step ST25. Specifically, by adding lime or the like that generates CaO by reaction and blowing in an oxygen-containing gas such as air, phosphorus in the alloy can be oxidized and absorbed in CaO.

  When the waste battery 30 is a lithium ion battery, the alloy obtained in this way is composed of cobalt, nickel derived from the positive electrode material, lithium derived from the electrolyte, copper derived from the negative electrode conductive material, and the like.

  In the present embodiment, an alloy shot forming step ST26 is performed at the end of the dry step S20. In this step, the alloy is cooled to obtain a granular material (also called a shot alloy or simply a shot). Thereby, melt | dissolution process ST31 in subsequent wet process S30 can be performed in a short time.

  As will be described later, by combining the dry process S20 and the wet process S30 by obtaining an alloy with few impurities by making the dry process S20 a pretreatment in a broad sense and significantly reducing the amount of processing to be put into the wet process S30. Is possible. However, since the wet process S30 is basically a complicated process that is not suitable for mass processing, in order to combine with the dry process S20, it is necessary to perform the processing time of the wet process S30, in particular, the dissolution process ST31 in a short time. Regarding the problem, the melting time can be shortened by granulating the alloy.

Here, the granules, it is preferable that the average surface area in terms of the surface area is 300 mm ² from 1 mm ^2, it is preferable from 0.4mg Speaking in average weight in the range of 2.2 g. If it is less than the lower limit of this range, it is not preferable because the particles are too fine and difficult to handle, and further, the reaction is too early and it becomes difficult to dissolve at once due to excessive heat generation. If the upper limit is exceeded, the dissolution rate in the subsequent wet process decreases, which is not preferable. As a method of granulating the alloy by shot, a conventionally known method of quenching by inflow of molten metal into flowing water can be used.

<Wet process S30>
The valuable metal recovery process from the waste battery is meaningless if it is recovered as an alloy as in Patent Document 1, and needs to be recovered as a valuable metal element. By processing the waste battery in advance in the dry process S20, the subsequent wet process S30 can be simplified by using an alloy of only valuable metals as described above. At this time, the amount of treatment in the wet process S30 is reduced from about 1/4 to about 1/3 in terms of mass ratio compared to the amount of input waste batteries, which makes the combination with the wet process S30 advantageous.

  As described above, it is industrially possible to combine the dry process S20 and the wet process S30 by obtaining an alloy with few impurities by making the dry process S20 a pretreatment in a broad sense and greatly reducing the processing amount. .

  The wet process S30 can use a conventionally known method and is not particularly limited. For example, in the case of an alloy composed of cobalt, nickel, copper, and iron when the waste battery is a lithium ion battery, after acid dissolution (dissolution step ST31), iron removal, copper separation recovery, nickel / cobalt separation, Valuable metal elements can be recovered through the element separation step ST32 in the procedures of nickel recovery and cobalt recovery.

<Processing amount>
Conventionally, in a total process that combines a dry process and a wet process, the oxidation process was performed in a state where the waste battery was melted in the dry process, so in order to appropriately adjust the degree of oxidation in the oxidation process, The melting process was required to be a batch process in which the next process was started again from the beginning after the oxidation process of all the waste batteries simultaneously processed in the furnace was completed. According to the organometallic recovery method of the present invention, the waste battery that has been subjected to the oxidation treatment in advance in the oxidation step ST20 can be continuously treated in the dry process by continuously putting it into the melting furnace. A large amount of processing is possible. The present invention can be suitably used when it is at least 1 t or more per day, preferably 10 t or more per day.

  The type of waste battery is not particularly limited, but a rare metal such as cobalt or lithium can be recovered, and its use has been expanded to automobile batteries, etc., and a lithium ion battery that requires a large-scale recovery process is the present invention. It can illustrate preferably as a process target.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

<Example 1>
Six waste lithium-ion batteries (18650 type: hereinafter referred to as “sample”) having a size of 18φ × 65 mm length were prepared and previously baked at 600 ° C. for 30 minutes. Then, CaO pulverized to a particle size of 1 mm or less on a setter (hereinafter simply referred to as a setter), which is a mullite roasting container made of alumina and silica having an inner diameter of 150 mm square and a depth of 40 mm. About 5 g of powder was uniformly loaded, and the sample after roasting was placed on the loaded CaO powder layer. Next, the setter was carried into a tunnel kiln in an air atmosphere and held at 1200 ° C. for 30 minutes for oxidation treatment.

  When the sample obtained by the oxidation treatment was tilted obliquely with the setter, the sample fell off the setter as it was without adhering to the setter. At the same time, the loaded CaO powder also dropped. On the other hand, no trace of reaction or sample burn-in was found on the setter.

<Example 2>
Six samples after baking that were baked under the same conditions as in Example 1 were subjected to oxidation treatment under the same conditions as in Example 1, loaded on a setter under the same conditions as in Example 1, and further samples after oxidation treatment The test in which the setter was tilted obliquely was repeated 8 times and tried. The CaO powder was added again to the setter every time.

  As a result of the test, the sample dropped as it was without adhering to the setter until the seventh trial. In the eighth trial, one remained attached to the setter.

<Comparative example>
Six samples after roasting as in Example 1 were oxidized under the same conditions as in Example 1 except that no CaO was loaded on the setter.

  When the sample after the oxidation treatment was tilted together with the setter, two of the six samples remained attached to the setter. The trace of the reaction was clearly recognized on the setter.

  From Examples 1 and 2 and the comparative example, the flux is loaded on the roasting container and the waste battery is placed on it, so that the sticking of the waste battery due to seizure can be prevented, and the cost of reusing the roasting container It was confirmed that it was possible to go down.

ST10 Roasting process ST20 Oxidation process S20 Dry process ST21 Melting process ST22 Slag separation ST23 Alloy separation ST24 Exhaust gas treatment ST25 Dephosphorization process ST26 Alloy shot process S30 Wet process ST31 Melting process ST32 Element separation process 1 Tunnel kiln 11 Kiln body 12 Transport means 13 Burner 14 Carry-in port 15 Discharge port 20 Container for roasting 30 Waste battery 40 Granular adhesion inhibitor

Claims (7)

A method for recovering valuable metals from a metal composite containing valuable metals,
An oxidation step of roasting and oxidizing the metal composite;
A melting step for obtaining a melt by melting the metal composite that has undergone the oxidation step;
A slag separation step of separating the slag from the melt and recovering an alloy containing a valuable metal, and
In the oxidation step, a granular adhesion inhibitor containing flux is loaded on the loading surface of the roasting container, and the metal complex is roasted in a state where the metal complex is placed on the granular adhesion inhibitor. It is a process of baking and oxidizing,
The melting step includes the metal composite that has been oxidized through the oxidation step, and a part or all of the particulate adhesion inhibitor loaded on the loading surface of the roasting container in the oxidation step. Is a process for recovering valuable metals, which is a step of melting by putting them in the same melting furnace.   The valuable metal recovery method according to claim 1, wherein the roasting container is a ceramic container.   The valuable metal recovery method according to claim 1 or 2, wherein the particulate adhesion inhibitor is a particulate mixture containing silicon dioxide and / or lime. The particulate adhesion inhibitor is a mixture of silicon dioxide and lime, and the weight ratio (SiO ₂ / CaO) of silicon dioxide (SiO ₂ ) and lime (CaO) in the particulate adhesion inhibitor is 0.5 or more and 1.5. The valuable metal recovery method according to any one of claims 1 to 3, wherein:   5. The valuable metal recovery method according to claim 1, wherein in the oxidation step, an oxidation treatment is performed in which the metal composite is roasted and oxidized at a temperature of 1000 ° C. to 1300 ° C. 5.   The valuable metal recovery method according to claim 1, wherein the oxidation step is performed using a tunnel kiln.   The valuable metal recovery method according to claim 1, wherein the metal composite is a lithium ion battery.

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