JP2021188067A - Preparation method of raw material to be melted, and valuable metal recovery method - Google Patents

Abstract

To provide a method capable of conducting an efficient reduction-melting process even to a raw material to be melted whose volume as a metal composite body as a whole is large with regard to a valuable metal.SOLUTION: A method is for recovering a valuable metal through reduction-melting, as a raw material to be melted, a roasted matter of a metal composite body containing the valuable metal. The method includes: a roasting process of roasting a metal composite body to obtain a roasted matter; a preparation process of a raw material to be melted, of mixing the roasted matter and a flux and granulating an obtained mixture to obtain a granulated matter; and a reduction-melting process of reduction-melting the granulated matter as a raw material to be melted to obtain an alloy containing a slag and the valuable metal.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for preparing a molten material and a method for recovering valuable metals.

Dry and wet methods can be broadly divided into preparation methods for recycling used or defective batteries (hereinafter referred to as waste batteries) such as lithium-ion batteries and recovering the valuable metals contained in them. be.

In the dry method, the crushed waste battery is melt-treated, and the valuable metal to be recovered and other metals with low added value are separated and recovered by utilizing the difference in oxygen affinity between them. .. That is, low value-added elements such as iron are oxidized as much as possible to form slag, and valuable resources such as cobalt are recovered as alloys by suppressing oxidation as much as possible.

For example, Patent Document 1 discloses a valuable metal recovery method including a dry method. According to Patent Document 1, this technology reduces the viscosity of slag to enable operation at low temperatures when dry-treating waste batteries such as lithium-ion batteries, and ensures the separation of slag and alloys, which is valuable. The metal can be recovered efficiently.

Japanese Unexamined Patent Publication No. 2012-224876

By the way, the reduction melting treatment in the valuable metal recovery method can be performed using, for example, a melting furnace. However, a metal composite such as a waste battery has a large volume of the entire metal composite with respect to the valuable metal, and can be charged per unit capacity of the melting furnace simply by charging the metal composite into the melting furnace as it is. It may not be possible to increase the weight of the molten material (hereinafter, also referred to as the filling bulk density in the furnace).

Further, if the filling bulk density in the furnace is low, the heat transferability of the molten material in the reduction furnace deteriorates, and it takes a long time to raise the temperature to a predetermined temperature required for reduction melting, which is efficient. It may not be possible to perform a proper reduction melting process.

The present invention has been proposed in view of such circumstances, and is a melting raw material capable of performing an efficient reduction melting treatment even if the melting raw material has a large volume of the entire metal composite with respect to a valuable metal. It is an object of the present invention to provide a method for preparing the above.

The present inventors have made extensive studies to solve the above-mentioned problems. As a result, they have found that the above problems can be solved by mixing the molten raw material with a flux to form a granulated product, and have completed the present invention.

(1) The first of the present invention is a melting raw material to be used in a reduction melting step of obtaining a slag and an alloy containing the valuable metal by reducing and melting a roasted metal composite containing a valuable metal as a melting raw material. This is a method for preparing a molten material obtained by mixing the roasted product and the flux and granulating the obtained mixture to obtain a granulated product.

(2) The second aspect of the present invention is, in the first invention, a method for preparing a molten raw material for obtaining a granulated product by applying a pressure of 2 t / cm or more to the mixture.

(3) The third aspect of the present invention is, in the first or second invention, the method for preparing a molten raw material in which the flux contains calcium carbonate.

(4) The fourth aspect of the present invention is the method for preparing a melting raw material in any one of the first to third inventions, further mixing water to obtain the mixture.

(5) Fifth of the present invention is the method for preparing a melting raw material in any one of the first to fourth inventions, wherein a binder is further mixed to obtain the mixture.

(6) A sixth aspect of the present invention is the method for preparing a molten raw material containing a waste lithium ion battery in the metal composite in any one of the first to fifth inventions.

(7) The seventh aspect of the present invention is a valuable metal recovery method for recovering a valuable metal by reducing and melting a roasted metal composite containing a valuable metal as a melting raw material, in which the metal composite is roasted. A roasting step of obtaining a roasted product, a melting raw material preparation step of mixing the roasted product and slag and granulating the obtained mixture to obtain a granulated product, and a reduction melting of the granulated product as a melting raw material. A valuable metal recovery method comprising a reduction melting step of obtaining an alloy containing the valuable metal.

According to the present invention, efficient reduction melting treatment can be performed.

It is a process drawing which shows an example of the flow of a valuable metal recovery method.

Hereinafter, a specific embodiment of the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.

≪1. Outline of preparation method of molten material ≫
The method for preparing a melting raw material according to the present embodiment is a raw material before melting (melting raw material) to be subjected to the melting treatment, which is the treatment target, when the reduction melting treatment is mainly performed by the valuable metal recovery method for recovering valuable metals. Is a method of preparing. Here, in the valuable metal recovery method, a metal composite containing a valuable metal is roasted to obtain a roasted product, and the roasted product is reduced and melted as a melting raw material to be subjected to a melting process, and contains slag and valuable metal. And get the alloy.

Specifically, in the method for preparing a melting raw material according to the present embodiment, a roasted metal composite used as a melting raw material is previously mixed with a flux to obtain a mixture (mixing step S41), and the obtained mixture is obtained. It is characterized in that it is granulated to obtain a granulated product (granulation step S42).

In this way, the melting raw material is mixed with the flux and granulated to obtain a granulated product, and the granulated product is charged into the melting furnace to increase the filling amount in the melting furnace and increase the filling bulk density in the furnace. be able to. Further, by mixing the roasted product and the flux to form a granulated product, the adhesion between the roasted product and the flux is enhanced in the granulated product, so that the thermal conductivity to the roasted product during the reduction melting process is improved. Also improves. As a result, the rate at which the temperature rises to a predetermined temperature required for reduction melting increases (heating rate), and efficient reduction melting treatment can be performed.

In addition, in this specification, a granulated product means a product which is granulated by integrally binding a roasted metal complex, and has a hardness at least enough to maintain its shape.

This granulated product is obtained by granulating a mixture of a roasted product and a flux, and has a hardness sufficient to maintain its shape. Therefore, for example, it is possible to convey the shape by a conveyor or the like without collapsing while maintaining the shape. As described above, the melting raw material obtained by the method for preparing the melting raw material according to the present embodiment has good handleability.

The melting raw materials to be treated include, for example, waste due to deterioration of automobiles or electronic devices, scrap of lithium ion batteries generated at the end of the life of lithium ion batteries, waste of defective products in the battery manufacturing process, and the like. Examples thereof include roasted metal composites including batteries and the like.

In the following, a method for preparing a molten raw material will be described together with each step of a valuable metal recovery method, taking as an example a case where a molten raw material obtained from a waste battery of a lithium ion battery is treated.

In the present invention, the molten material to be treated is not limited to the roasted metal composite containing the waste battery, but the waste battery is derived from a battery pack or the like in addition to the valuable metal derived from the electrode. Since it contains a large amount of metal other than the valuable metal, the volume of the entire metal composite becomes larger than that of the valuable metal. For this reason, there is a tendency that the problem that the filling bulk density in the furnace cannot be increased and the efficient reduction melting treatment cannot be performed is likely to occur. Therefore, the roasted metal composite including the waste battery is to be treated. Therefore, the benefits of the present invention can be suitably enjoyed.

≪2. Each process of valuable metal recovery method ≫
Hereinafter, a method for preparing a molten material will be described together with a method for recovering valuable metals, which is a prerequisite for the method.

Specifically, as a valuable metal recovery method, as shown in FIG. 1, the waste battery pretreatment step S1 for removing the electrolytic solution and the outer can from the waste battery and the waste battery used in the waste battery pretreatment step S1 are crushed. The crushing step S2 to obtain the crushed product, the roasting step S3 to obtain the roasted product by roasting the crushed product, and the mixture obtained by mixing the roasted product and the flux are granulated to obtain the granulated product. It has a melting raw material preparation step S4 and a reduction melting step S5 in which a granulated product is reduced and melted as a melting raw material to obtain an alloy containing a slag and a valuable metal.

[Waste battery pretreatment process]
In the waste battery pretreatment step S1, the electrolytic solution and the outer can are removed from the waste battery. Since the waste battery contains an electrolytic solution or the like, there is a risk of explosion if the crushing process is performed as it is. In addition, the outer cans contained in the waste battery often contain gold aluminum, iron, and the like, and the outer cans such as aluminum and iron can be recovered as valuable metals relatively easily. By removing the electrolytic solution and the outer can from the battery through this step, the safety can be enhanced and the recovery productivity of valuable metals such as copper, nickel and cobalt can be enhanced.

The specific method of the waste battery pretreatment step S1 is not particularly limited, and examples thereof include a method of physically opening the waste battery with a needle-shaped cutting edge to remove the electrolytic solution and the outer can. Further, the waste battery may be heated to burn the electrolytic solution to make it harmless.

In the waste battery pretreatment step S1, for example, when aluminum or iron contained in an outer can is recovered, the removed outer can can be crushed and then sieved using a sieve shaker. In the case of aluminum, even light pulverization easily becomes powdery, so that aluminum can be efficiently recovered from the outer can. In addition, iron can be recovered from the outer can by sorting by magnetic force.

[Crushing process]
In the crushing step S2, the waste battery (metal complex) used in the waste battery pretreatment step S1 is crushed to obtain a crushed product. As a result, the reaction efficiency can be increased in the reduction melting step S5 described later, and the recovery rate of valuable metals such as copper, nickel, and cobalt can be increased.

The crushing device used in the crushing treatment is not particularly limited, and crushing can be performed using a conventionally known crusher such as a cutter mixer.

[Roasting process]
In the roasting step S3, the crushed product of the waste battery is roasted to obtain a roasted product. When carbon is contained in the melting raw material, agglutination of the metal is inhibited in the reduction melting step S5 described later, the separability between the metal and the slag is lowered, and the recovery rate of the valuable metal is lowered. Therefore, by roasting the crushed product to oxidize and remove the carbon contained in the crushed product, the metal and the slag are effectively separated in the reduction melting step S5 described later, and the recovery rate of the valuable metal is improved. Can be made to.

Further, in the roasting step S3, at least aluminum among the metals contained in the pulverized product is oxidized. As a result, the aluminum contained in the pulverized product can be separated from the metal as slag in the reduction melting step S5 described later.

The conditions for the roasting treatment are not particularly limited, but it is preferable to carry out the roasting treatment at least with an degree of oxidation capable of oxidizing carbon and aluminum contained in the pulverized product. Specifically, the roasting temperature is preferably 700 ° C. or higher. The upper limit of the roasting temperature is not particularly limited, but is preferably 900 ° C. or lower. If the roasting temperature is too high, a part of iron, etc., which is mainly used for the outer shell of the waste battery, adheres to the inner wall of the roasting furnace body such as a kiln, which hinders smooth operation. Or, it may lead to deterioration of the kiln itself, which is not preferable.

Further, in adjusting the degree of oxidation during the roasting treatment, it is preferable to introduce an appropriate amount of an oxidizing agent into the furnace. The oxidizing agent is not particularly limited, but it is preferable to use a gas containing oxygen such as air, pure oxygen, and oxygen-enriched gas from the viewpoint of easy handling. The amount of the oxidizing agent introduced can be, for example, about 1.2 times the chemical equivalent required for the oxidation of each substance to be oxidized.

[Melting raw material preparation process]
The melting raw material preparation step S4 is a step of preparing a raw material (melting raw material) to be subjected to the reduction melting treatment in the reduction melting step S5 of the next step. Specifically, in the melting raw material preparation step S4, the roasted product and the flux are mixed to obtain a mixture (mixing step S41), and the obtained mixture is granulated to obtain a granulated product (granulation step S42). ).

In this way, prior to the reduction melting treatment, the roasted product to be melted and the flux are mixed and granulated to obtain a granulated product containing the roasted product and the flux. Then, by charging the melting raw material in the form of such a granulated product into a melting furnace and subjecting it to the reduction melting process, the filling amount in the furnace and the filling bulk density are increased, and the thermal conductivity to the roasted product is improved. It can be improved and enables efficient reduction melting treatment.

Hereinafter, the mixing step S41 and the granulation step S42 included in the melting raw material preparation step S4 will be described.

(Mixing process)
In the mixing step S41, the roasted product obtained in the roasting step S3 and the flux are mixed to obtain a mixture. Conventionally, generally, a flux is added to a melting furnace during a reduction melting process for the purpose of melting and removing slag. In the method for preparing a melting raw material according to the present embodiment, prior to the reduction melting treatment, a roasted product and a flux are mixed in advance to obtain a mixture, and the mixture is granulated in the granulation step S42 described later. Produce granules.

The flux may be any ordinary flux that has been conventionally added and used during the reduction melting treatment, and is not particularly limited. For example, those containing calcium as a main component such as calcium oxide and calcium carbonate, and those containing magnesium such as magnesium oxide as a main component can be mentioned.

Among them, a flux containing calcium such as calcium oxide or calcium carbonate as a main component is preferable. In this way, by mixing the flux containing calcium as the main component with the roasted product and granulating it into the form of the granulated product, the strength characteristics of the obtained granulated product are improved and the filling amount in the furnace is improved. And the filling bulk density can be increased more effectively. In addition, as the thing containing calcium as a main component, the thing containing calcium carbonate is preferable from the viewpoint of cost.

The lower limit of the mixing ratio of the flux to the roasted product is preferably 10 parts by mass or more, and more preferably 20 parts by mass or more with respect to 100 parts by mass of the roasted product in the mixture. The upper limit of the content ratio of the flux is preferably 50 parts by mass or less, and more preferably 40 parts by mass or less with respect to 100 parts by mass of the roasted product in the mixture.

Also, the flux itself functions as a binder. Therefore, by mixing the roasted product and the flux and granulating the obtained mixture, it is possible to effectively obtain the granulated product integrally bonded.

When mixing the roasted product and the flux, various mixers such as a Henschel mixer can be used. Further, water or a binder may be mixed as an additive of an arbitrary component. As described above, since the flux itself has a function as a binder, it is not always necessary to mix water or a binder, but by mixing water or a binder to form a granulated product, it is produced. The strength characteristics of the granules are further improved. The granulated product obtained without mixing water or a binder is excellent in terms of operating cost because the step of drying the granulated product is not required.

When carbon is used as the reducing agent in the reduction melting step S5 described later, carbon may be contained in the mixture together with the flux.

(Granulation process)
In the granulation step S42, the mixture obtained in the mixing step S41 is granulated to obtain a granulated product. Specifically, for example, using a granulator, the obtained mixture is granulated by applying a predetermined pressure (linear pressure) that can integrally bond the obtained mixture, and has a hardness sufficient to maintain its shape. Obtain granulation.

The pressure (linear pressure) applied when granulating the mixture is not particularly limited, but the lower limit is preferably 1.0 t / cm or more, and 1.5 t / cm or more. Is more preferable, and 2.0 t / cm or more is further preferable. The upper limit is not particularly limited, but it is preferably 4.0 t / cm or less because the filling bulk density in the furnace cannot be increased even if it exceeds 4.0 t / cm.

In the case of the granulated product thus obtained, the flux functions as a binder, and the granulated product integrally bonded by the pressure (linear pressure) applied at the time of granulation can be obtained. Further, since it is in the form of a granulated product, the adhesion between the roasted product and the flux in the granulated product is enhanced, and the thermal conductivity to the roasted product can be improved.

[Reduction melting process]
In the reduction melting step S5, the granulated product is reduced and melted as a melting raw material to obtain a slag and an alloy containing a valuable metal. In the reduction melting step S5, unnecessary oxides such as aluminum oxidized in the roasting step S3 remain as oxides, and the oxides of valuable metals such as copper oxidized in the roasting step S3 are reduced and melted. The purpose is to recover the reduced product as an integrated alloy. The alloy obtained as a melt is also referred to as "fused gold".

Here, in the present embodiment, in the melting raw material preparation step S4, prior to the reduction melting of the melting raw material, a mixture obtained by mixing the melting raw material and the flux is granulated to obtain a granulated product. .. Therefore, by charging this granulated product into a melting furnace as a melting raw material, it is possible to increase the filling amount in the melting furnace and increase the filling bulk density in the furnace, and it is possible to increase the melting processing amount and efficiently. It becomes possible to perform a reduction melting process. Further, since it is in the form of a granulated product, the adhesion between the roasted product and the flux in the granulated product is enhanced, and the thermal conductivity to the roasted product during the reduction melting treatment can be improved. As a result, the rate of raising the temperature to a predetermined temperature required for reduction melting (heating rate) is increased, the melting process time is shortened, and more efficient reduction melting process can be performed.

The reduction melting step S5 is preferably carried out in the presence of, for example, carbon or carbon monoxide. Carbon has the ability to easily reduce valuable metals such as copper, nickel, and cobalt to be recovered. For example, 1 mol of carbon reduces 2 mol of an oxide of a valuable metal such as copper oxide or nickel oxide. It is a reducing agent that can be used. Further, the reduction using carbon or carbon monoxide is extremely safe as compared with the case of using the thermite reaction in which a metal powder such as aluminum is reduced as a reducing agent.

As carbon, in addition to artificial graphite and natural graphite, coal, coke and the like can be used if there is no risk of contamination of impurities.

The temperature condition (melting temperature) in the melting treatment is not particularly limited, but is preferably 1300 ° C. or higher and 1500 ° C. or lower. If the melting temperature is lower than 1300 ° C., the fluidity of the fused metal may deteriorate, and the separation efficiency of impurities and valuable metals may deteriorate. On the other hand, if the melting temperature is set to a temperature exceeding 1500 ° C., heat energy is wasted, the consumption of refractories such as crucibles becomes severe, and productivity may decrease. Therefore, the melting temperature is preferably 1500 ° C. or lower.

The melting furnace may be a burner furnace having a burner or an electric furnace having a heating means using electricity or the like, but an electric furnace is preferable.

In the melting process, it is preferable to use flux. By melting the reduced product with flux, slag containing an oxide such as aluminum can be dissolved in the flux and removed. In the present embodiment, since the granular material which is the melting raw material contains a predetermined amount of flux, it is not always necessary to use the flux in the melting process.

When a flux is used in the melting treatment, the flux preferably contains calcium as a main component, and for example, calcium oxide or calcium carbonate can be used. From the viewpoint of cost, those containing calcium carbonate are more preferable. The flux in the melting treatment may be the same as or different from the flux contained in the granules.

Further, sulfur may be added to the alloy obtained in the reduction melting step before the alloy is recovered, whereby the alloy can be made brittle and easily crushed. By crushing the alloy, the specific surface area can be increased, which can improve the leachability in the hydrometallurgical process.

When phosphorus is contained in the melting raw material, phosphorus becomes an acidic oxide when oxidized. Therefore, the more basic the composition of slag, the easier it is to remove phosphorus to slag. It is better that the amount of calcium as a basic oxide in the slag is large, and the amount of silicon as an acidic oxide is small, and it is particularly preferable that the mass ratio of silicon dioxide / calcium oxide in the slag is 0.5 or less. In addition, since the melting point of slag rises when the ratio of aluminum oxide is large, a sufficient amount of calcium is required to melt aluminum oxide, and the mass ratio of calcium oxide / aluminum oxide in slag is 0.3. It is preferably 2 or less. This makes the slag basic and can effectively remove phosphorus that produces acid oxides. In the melting treatment, dust, exhaust gas, etc. may be generated, but it can be detoxified by performing a conventionally known exhaust gas treatment.

As described above, since phosphorus can be removed by the above-mentioned dry treatment process, the process can be simplified when the recovered fused gold is used for a hydrometallurgical process. At this time, it is also an advantage that the processing amount in this hydrometallurgical process is reduced to about 1/4 to 1/3 in terms of mass ratio with respect to the amount of input waste batteries. Therefore, by making the dry step (waste battery pretreatment step S1 to reduction melting step S5) a pretreatment in a broad sense, an alloy with less impurities (phosphorus) can be obtained and the amount of treatment can be significantly reduced, so that the dry smelting process can be performed. It is industrially possible to combine and wet smelting processes.

The treatment in the hydrometallurgical process can be performed by a known method such as a neutralization treatment or a solvent extraction treatment, and is not particularly limited. For example, in the case of an alloy composed of cobalt, nickel, and copper, after leaching a valuable metal with an acid such as sulfuric acid (leaching step), for example, copper is extracted by solvent extraction (extraction step), and the remaining nickel. And the solution containing copper is to be dispensed to the positive electrode active material manufacturing process in the battery manufacturing process.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1]
The electrolyte and the outer can are removed from the waste battery of a lithium-ion battery containing copper, aluminum, and carbon as the main components, and nickel, cobalt, iron, and lithium (waste battery pretreatment step), and crushed to obtain a crushed product. (Crushing process). _{Then, 0.16 tons of CaCO 3} (calcium carbonate) was added as a flux to 0.54 tons of the roasted product obtained by roasting the crushed product (roasting step) and performing an oxidation treatment, and the mixture was mixed with a Henshell mixer to obtain 0 mixture. .70t was obtained (mixing step). This mixture was pressurized using a briquette machine having a roll having a diameter of 650 mm and a width of 100 mm under the conditions of a linear pressure of 2.0 t / cm and a rotation speed of 3 rpm to obtain granulated products (30 mm × 25 mm × 7.5 mm). (Granulation process).

Then, this granulated product was conveyed by a conveyor and charged into a melting furnace (electric furnace) so that the charging amount was 60 L. From the weight (hereinafter, also referred to as the filling amount in the furnace) and the volume of the raw material charged at this time, the filling bulk density of the raw material charged into the furnace (hereinafter, also referred to as the filling bulk density in the furnace) is obtained. rice field.

Next, the melting furnace (electric furnace) was energized with an average output of 130 kW to raise the temperature of the charged raw material to 1400 ° C. The time required for this temperature rise was measured, and the temperature rise rate was determined.

Further, in order to evaluate the effect of shortening the melting time, a model for melting 200 kg of the raw material was assumed, and the melting time was estimated from the filling amount in the furnace and the obtained temperature rising rate. At this time, the melting time was calculated by the following formula in consideration of the fact that the granulated product at the start of melting was at room temperature (25 ° C.).
Melting time = 200 [kg] ÷ filling amount in the furnace [kg] × ((1400 [° C] -25 [° C]) ÷ heating rate [° C / h])

[Example 2]
The same procedure as in Example 1 was carried out except that the pressurizing condition of the briquette machine in the granulation step was a linear pressure of 3.0 t / cm.

[Example 3]
Water of 1.0 tw% by weight with respect to the mixture in the mixing step was added to the mixture, the pressure condition of the briquette machine was set to a linear pressure of 3.0 t / cm, and the obtained granulated product was dried. Except for the above, the same procedure as in Example 1 was performed.

[Example 4]
1.0 wt% of water and 1.0 wt% of binder (α-starch) by weight ratio with the mixture in the mixing step are added to the mixed raw material, and the pressurizing condition of the briquette machine is set to 3.0 t. The process was carried out in the same manner as in Example 1 except that the pressure was applied to / cm and the obtained granulated product was dried.

[Example 5]
The same procedure as in Example 1 was carried out except that the pressurizing condition of the briquette machine in the granulation step was a linear pressure of 1.0 t / cm.

[Comparative Example 1]
The same procedure as in Example 1 was carried out except that the mixture was not granulated in the granulation step and the mixture itself was charged into a melting furnace (electric furnace).

Table 1 shows the amount of sintered material, the amount of flux, the amount of granulated material, and the granulated linear pressure in each Example and Comparative Example. Table 2 shows the filling amount in the furnace, the bulk density in the filling in the furnace, the heating rate, and the melting time when 200 kg of the raw material is melted in each Example and Comparative Example.

As can be seen from Tables 1 and 2, Examples 1 to 1 prepared a granulated product obtained by granulating a mixture of a roasted waste battery and a flux, and subjected a reduction melting treatment in the form of the granulated product. In No. 5, the filling amount in the furnace and the filling bulk density can be increased, and the rate of raising the temperature to a predetermined temperature required for reduction melting (heating rate) is increased, so that the melting time of the object to be treated is effective. I was able to shorten it to.

Further, in Examples 1 to 4 in which the granulation wire pressure was set to 2.0 t / cm or more and granulated, the filling in the furnace was made as compared with Example 5 in which the granulation wire pressure was set to 1.0 t / cm. It can be seen that the bulk density can be further increased and the time required for raising the temperature to a predetermined temperature required for reduction melting can be further shortened. Further, in Examples 2 to 4 in which the granulation linear pressure was set to 3.0 t / cm or more and the granulation was performed, the filling bulk density in the furnace could be further increased, and the temperature was raised to a predetermined temperature required for reduction melting. It can be seen that the time can be further reduced. Therefore, more efficient reduction melting treatment can be performed by granulating with a pressure (linear pressure) of 2.0 t / cm or more, and more preferably a pressure (linear pressure) of 3.0 t / cm or more. I know I can do it.

Further, in Examples 3 and 4 in which water was added and the obtained granulated product was dried, the filling bulk density in the furnace could be further increased, and the time required for the temperature to rise to a predetermined temperature required for reduction melting. It turns out that can be further shortened. By adding water and drying the obtained granulated product, the granulated product becomes stronger and its strength characteristics are improved, and the granulated product collapses when it is transported by a conveyor or charged into an electric furnace. It is considered that this is because the number of substances has decreased and the filling density has increased.

Further, in Example 4 in which the granulation is performed by adding a binder, it can be seen that the filling bulk density in the furnace can be further increased and the time required for raising the temperature to a predetermined temperature required for reduction melting can be further shortened. .. It is considered that this is because the addition of the binder further strengthens the granulated product, further improves the strength characteristics, and further exerts the above-mentioned effect.

Claims (7)

A method for preparing a melting raw material to be used in a reduction melting step of obtaining a slag and an alloy containing the valuable metal by reducing and melting a roasted metal composite containing a valuable metal as a melting raw material.
A method for preparing a molten raw material, in which the roasted product and the flux are mixed and the obtained mixture is granulated to obtain a granulated product. The method for preparing a molten raw material according to claim 1, wherein a granulated product is obtained by applying a pressure of 2 t / cm or more to the mixture. The method for preparing a melting raw material according to claim 1 or 2, wherein the flux contains calcium carbonate. The method for preparing a melting raw material according to any one of claims 1 to 3, wherein water is further mixed to obtain the mixture. The method for preparing a melting raw material according to any one of claims 1 to 4, wherein a binder is further mixed to obtain the mixture. The method for preparing a melting raw material according to any one of claims 1 to 5, wherein the metal complex includes a waste lithium ion battery. It is a valuable metal recovery method for recovering valuable metal by reducing and melting a roasted metal complex containing valuable metal as a melting raw material.
The roasting process of roasting the metal complex to obtain a roasted product,
A step of preparing a molten raw material, in which the roasted product and the flux are mixed and the obtained mixture is granulated to obtain a granulated product.
A reduction melting step of reducing and melting the granulated product as a melting raw material to obtain a slag and an alloy containing the valuable metal.
Valuable metal recovery method.

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