KR101938280B1 - Recycling method of tungsten scrap having metal coating layer - Google Patents

Abstract

The present invention relates to a method for recycling a tungsten scrap formed with a metal coating layer, which comprises treating a tungsten scrap formed with a metal coating layer with a basic solution, pulverizing the same, treating the tungsten scrap with an acidic solution, The present invention provides a method of recycling a tungsten scrap in which a metal coating layer capable of recovering high purity tungsten powder is formed from a tungsten scrap having a metal coating layer formed thereon by washing and oxidation and reduction.

Description

TECHNICAL FIELD [0001] The present invention relates to a recycling method of a tungsten scrap having a metal coating layer,

The present invention relates to a method for recycling a tungsten scrap formed with a metal coating layer, and more particularly, to a method for recycling a tungsten scrap generated from a tungsten filament formed with an aluminum coating layer.

The present invention is a result of research conducted by the Ministry of Commerce, Industry and Energy and the Korea Energy Technology Evaluation & Consulting Service under the support of the "Energy resource circulation technology development project" (task number: 1415145563, detailed project number: 20165020301260).

Tungsten is heavy and hard, has a high melting point, low vapor pressure, and is used as a filament component for incandescent lamps, vacuum tubes, cathode tubes and halogen lamps. As the incandescent lamp, the vacuum tube, the cathode tube, the halogen lamp, and the like emit heat by various reactions, the internal temperature of the incandescent lamp, the cathode tube, and the halogen lamp becomes very high when they are used for a long period of time, resulting in deterioration or vaporization of the tungsten filament. In recent years, the above problems have been solved by coating various metals on tungsten filaments. Among them, the use of tungsten filaments coated with aluminum metal is increasing due to their excellent performance.

On the other hand, since tungsten is a very expensive metal, a tungsten scrap is formed in which a plurality of metal coating layers are formed during the use of tungsten in which a metal coating layer is formed. Since tungsten is an expensive metal, various methods for recovering and recycling pure tungsten after removing the metal coating layer and impurities from a tungsten scrap formed with a metal coating layer are generally known.

Tungsten scrap or tungsten slurry is recycled mainly by sodium salt melting process and zinc treatment method considering the shape and regeneration of raw materials, but it is suitable only for tungsten scrap. In the above methods, tungsten scrap having aluminum coating layer or vapor deposition layer on its surface, There was a difficulty in obtaining tungsten powder.

Korean Patent No. 10-1311712 discloses a method for removing a coating film by charging a waste cemented carbide (tungsten) having a coating film formed of aluminum on its surface into a hydrogen peroxide solvent or a mixed solvent of water and water. The above patent has a problem in that the process is complicated because a hydrogen peroxide solution having a very strong oxidizing power is used at a high concentration as compared with a general acidic solution, and a pretreatment and a post treatment are performed for use of hydrogen peroxide. Although the ultrasonic wave treatment is started in the above-mentioned patent, the frequency of the ultrasonic wave is very wide, from 10 kHz to 5 MHz (5000 kHz), and it is difficult to derive the frequency range for improving the peeling effect of the metal coating layer.

Accordingly, there is a demand for a method of recycling tungsten scrap that can recover tungsten of high purity from tungsten scrap formed with a metal coating layer while solving the above problems.

Korea Patent No. 10-0656807

An object of the present invention is to provide a method of recycling a tungsten scrap in which a metal coating layer capable of recovering high purity tungsten (powder) from a tungsten scrap formed with a metal coating layer is formed.

The object of the present invention is not limited to the above-described technical problems, and another technical problem can be derived from the following description.

The method includes the steps of: (a) treating a tungsten scrap with a basic solution; (b) pulverizing the tungsten scrap treated with the basic solution to form a tungsten scrap powder; (c) Treating the scrap powder with an acidic solution, (d) washing the tungsten scrap powder treated with the acidic solution with a cleaning composition comprising a surfactant and a solvent, (e) oxidizing the washed tungsten scrap powder And (f) reducing the tungsten oxide powder to form tungsten powder, wherein the tungsten scrap in the step (a) is a method of recycling a tungsten scrap formed with a metal coating layer on which a metal coating layer is formed .

In the step (a), ultrasonic treatment can be performed.

In the step (a), the ultrasonic treatment may be performed at a frequency of 30 to 35 kHz and an amplitude of 20 to 30 μm.

The metal coating layer may be an aluminum coating layer.

In the step (b), the tungsten scrap powder may have a particle diameter of 80 to 100 micrometers.

The cleaning composition may contain 15 to 40% by weight of a surfactant based on the total weight of the cleaning composition and a residual amount of a solvent.

The surfactant may include a polyoxyalkylene alkyl ether, a sorbitan fatty acid ester, and a polyoxyalkylene sorbitan fatty acid ester in a weight ratio of 1: 0.5 to 2: 0.5 to 2.

The basic solution may include at least one selected from the group consisting of a sodium hydroxide (NaOH) solution, a calcium hydroxide (Ca (OH) ₂ ) solution and a potassium hydroxide (KOH) solution.

The acidic solution may include one or more selected from the group consisting of a hydrochloric acid (HCl) solution, a nitric acid (HNO ₃ ) solution, and a sulfuric acid (H ₂ SO ₄ ) solution.

The present invention relates to a method for producing a metal coating layer, which comprises treating a basic solution of a tungsten scrap formed with a metal coating layer with a basic solution, treating the solution with an acidic solution, washing it with a cleaning composition containing a surfactant and a solvent, High-purity tungsten (powder) can be recovered from tungsten scrap.

Particularly, the treatment of the tungsten scrap formed with the metal coating layer with the basic solution can also facilitate the recovery of the high-purity tungsten powder by performing the ultrasonic treatment. Also, by washing with a cleaning composition comprising a polyoxyalkylene alkyl ether, a sorbitan fatty acid ester and a polyoxyalkylene sorbitan fatty acid ester in a specific ratio, the recovery of the high purity tungsten powder is easier .

1 is a flowchart illustrating a method of recycling a tungsten scrap formed with a metal coating layer according to an embodiment of the present invention.
2 is a diagram showing the results of a tungsten purity analysis test of Example 4. Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted.

It is to be understood that the terms or words used in the specification and claims are not to be construed in a conventional or dictionary sense and that the inventor may properly define the concept of a term in order to best describe its invention And should be construed in accordance with the principles and meanings and concepts consistent with the technical idea of the present invention.

In the specification of the present invention, when a component is referred to as " comprising ", it means that it can include other components as well as other components, .

Throughout the specification of the present invention, " A and / or B " means A or B, or A and B.

Throughout the specification of the present invention, "tungsten scrap formed with a metal coating layer" may mean scrap generated during processing, use and disposal of tungsten in which a metal coating layer is formed, but is not limited thereto.

Throughout the specification of the present invention, "a method of recycling a tungsten scrap formed with a metal coating layer" means a method of recovering high-purity tungsten (powder) from scraps generated during processing, use and disposal of tungsten in which a metal coating layer is formed But is not limited thereto.

Throughout the specification of the present invention, the term " metal coating layer " means a coating layer of all metals that can be formed on the tungsten surface, preferably an aluminum coating layer, more preferably an aluminum deposition layer.

The present invention has been specifically described below, but the present invention is not limited thereto.

The present invention provides a method of recycling a tungsten scrap formed with a metal coating layer.

(A) treating the tungsten scrap with a basic solution, (b) pulverizing the tungsten scrap treated with the basic solution to form a tungsten scrap powder, (c) (D) washing the tungsten scrap powder treated with the acidic solution with a cleaning composition comprising a surfactant and a solvent, (e) oxidizing the washed tungsten scrap powder to remove tungsten oxide powder And (f) reducing the tungsten oxide powder to form a tungsten powder. The tungsten scrap having a metal coating layer capable of recovering high purity tungsten (powder) from a tungsten scrap formed with a metal coating layer, A method for recycling of the same. In particular, when the metal coating layer is a metal deposition layer, separation from tungsten is difficult. However, according to the recycling method of the tungsten scrap formed with the metal coating layer according to the present embodiment, the metal deposition layer can also be easily separated or removed.

1 is a flowchart illustrating a method for recycling a tungsten scrap formed with a metal coating layer according to an embodiment of the present invention.

(a) treating the tungsten scrap with a basic solution (10)

In the step (a) of this embodiment, the tungsten scrap is treated with a basic solution, and the tungsten scrap is formed with a metal coating layer. The metal coating layer may preferably be an aluminum coating layer, more preferably an aluminum deposition layer, but is not limited thereto.

 More specifically, in the step (a) of the present embodiment, the metal coating layer formed on one side of the tungsten scrap can be removed by immersing the tungsten scrap formed with the metal coating layer in the basic solution so as to be sufficiently immersed, followed by heating and stirring. Accordingly, after the tungsten scrap formed with the metal coating layer is subjected to the step (a) of the present embodiment, the tungsten scrap in which the metal coating layer is removed and the tungsten scrap in which the metal coating layer is not removed may be mixed.

The basic solution of the present embodiment may include at least one selected from the group consisting of a sodium hydroxide (NaOH) solution, a calcium hydroxide (Ca (OH) ₂ ) solution and a potassium hydroxide (KOH) solution, Any basic solution that can be used is not limited. The basic solution of this embodiment may preferably be a sodium hydroxide solution, more preferably a 3 to 10% sodium hydroxide solution, but is not limited thereto.

If the metal coating layer is an aluminum deposition layer, it can be reacted as shown in the following (1) to (3).

(1) 2Al + 2NaOH + 2H 2 O → 2NaAlO 2 + 3H 2 (g)

(2) NaAlO ₂ + 2H ₂ O? Al (OH) ₃ (S) + NaOH

_{(3) 2Al (OH) 3} → Al 2 O 3 + 3H 2 O

In the step (a) of this embodiment, heating may be performed, and heating in the step (a) of this embodiment may be carried out at 80 to 100 ° C, preferably 83 to 95 ° C, more preferably 85 to 93 ° C have. If the temperature is lower than 80 캜, the reaction between the metal coating layer and the basic solution may not be sufficiently activated. On the other hand, if heated above 100 ° C, moisture of the basic solution evaporates to cause difficulty in the reaction, and problems such as ignition, smoke generation, and by-product formation may occur due to the chemical reactivity of the basic solution.

In the step (a) of this embodiment, stirring may be performed, and the stirring speed and stirring tool are not limited to each other, and all known methods may be applied.

Meanwhile, in the step (a) of this embodiment, ultrasonic treatment can be performed under the conditions of a frequency of 30 to 35 kHz and an amplitude of 20 to 30 μm in order to activate the peeling, melting or melting of the metal coating layer from the tungsten scrap formed with the metal coating layer have.

In the step (a), the ultrasonic treatment may be performed at a frequency of 30 to 35 kHz and an amplitude of 20 to 30 μm. The frequency may be 30 to 35 kHz, preferably 30 to 33 kHz, and more preferably 31 to 32 kHz.

If the frequency is less than 30 kHz during the ultrasonic treatment, there may be a problem that the peeling, melting or melting of the metal coating layer is not sufficiently activated by the ultrasonic treatment. If the frequency exceeds 35 kHz during the ultrasonic treatment, And by-products are formed, and such by-products adhere to the surface of the tungsten, which may cause a problem of lowering the recovery efficiency or purity of tungsten.

In the step (a), the ultrasonic treatment may be performed under the condition that the frequency is 30 to 35 kHz, and the amplitude is 20 to 30 μm (micrometer), whereby the peeling of the metal coating layer by ultrasonic treatment, Melting or melting can be sufficiently activated. If the amplitude is less than 20 μm, the effect of ultrasonic treatment may be insignificant. If the amplitude is more than 30 μm, the efficiency may be low, which may result in an economical problem.

That is, in the step (a) of this embodiment, by performing the ultrasonic treatment while treating the basic solution, the peeling, melting or melting of the metal coating layer is activated from the tungsten scrap formed with the metal coating layer to efficiently recover high purity tungsten .

(b) milling the tungsten scrap treated with the basic solution to form tungsten scrap powder (20)

In step (b) of the present embodiment, the tungsten scrap treated with the basic solution in step (a) of the present embodiment may be pulverized to form tungsten scrap powder, and preferably fine pulverized.

The tungsten scrap treated with the basic solution in step (b) of this embodiment can be finely pulverized by any known method, whereby the tungsten scrap powder has a particle size of 80 to 100 micrometers, preferably 85 to 95 micrometers, And more preferably from 85 to 90 micrometers.

If the particle diameter of the tungsten scrap powder is less than 80 micrometers, there may be a problem that the tungsten scrap powder forms a lump due to the cohesive force between the tungsten scrap powder particles. As a result, the cleaning with the acidic solution in the step (c) and the cleaning composition in the step (d) can not be efficiently carried out, and recovery of high purity tungsten may be difficult. On the other hand, if the particle size of the tungsten scrap powder exceeds 100 micrometers, the cleaning with the acidic solution in step (c) and the cleaning composition in step (d) can not be efficiently performed and uniform heating of the tungsten scrap powder There is a problem that it is difficult to recover high-purity tungsten.

In the step (b) of the present embodiment, the tungsten scrap formed with the metal coating layer may be firstly pulverized using a jaw crusher, and then finely pulverized using a ball mill, but the present invention is not limited thereto.

(c) treating (30) the tungsten scrap powder with an acidic solution,

In step (c) of this embodiment, the tungsten scrap powder of step (b) of the present embodiment may be treated with an acidic solution, and the treatment with the acidic solution may be such that the tungsten scrap powder is immersed sufficiently in the acidic solution, But is not limited thereto. More specifically, in step (c) of the present embodiment, the tungsten scrap powder of step (b) of this embodiment is soaked in the acidic solution sufficiently to be immersed therein, followed by heating and stirring to remove the metal coating layer that has not been removed in step . Thereby, the purity of the recovered tungsten can be further increased.

The acidic solution of the present embodiment may include one or more selected from the group consisting of a hydrochloric acid (HCl) solution, a nitric acid (HNO ₃ ) solution and a sulfuric acid (H ₂ SO ₄ ) solution, Can be applied without limitation as long as it can peel, dissolve or melt the metal coating layer. The acid solution of this embodiment may be a nitric acid solution, more preferably a 1 to 5% nitric acid solution, but is not limited thereto.

In step (c) of this embodiment, heating may be performed. Heating in step (a) of this embodiment may be carried out at 50 to 70 ° C, preferably at 53 to 65 ° C, more preferably at 55 to 62 ° C have. If heated to less than 50 캜, the reaction between the metal coating layer and the acidic solution may not be sufficiently activated. On the other hand, when the temperature exceeds 70 ° C, moisture of the acidic solution may be evaporated and the reaction may be difficult. In addition, the chemical reactivity of the acidic solution may cause problems such as ignition, smoke generation, and by-product formation.

In the step (c) of the present embodiment, stirring may be performed, and the stirring speed and stirring tool are not particularly limited, and all known methods may be applied.

In the step (c) of the present embodiment, the ultrasonic treatment may be performed in the same manner as in the step (a), but the present invention is not limited thereto.

(d) washing (40) the tungsten scrap powder treated with the acidic solution with a cleaning composition comprising a surfactant and a solvent,

In step (d) of this embodiment, the tungsten scrap powder treated with the acidic solution in step (c) of this embodiment may be washed with a cleaning composition containing a surfactant and a solvent. More specifically, since the tungsten scrap powder treated with the acidic solution in step (c) of the present embodiment is in a state in which residual acidic solution or various by-products are present or mixed, the step (d) The cleaning composition can be used to remove residual acidic solution or various by-products. As a result, it is possible to recover tungsten having a higher purity.

The cleaning composition of the present embodiment may contain 15 to 40% by weight of a surfactant and a residual amount of a solvent based on the total weight of the cleaning composition. If the surfactant is contained in an amount of less than 15 wt% based on the total weight of the cleaning composition of the present invention, the cleaning efficiency may not be sufficient. If the surfactant is contained in an amount exceeding 40 wt%, the tungsten scrap powder The surface active agent may be adhered or adsorbed on the surface of the tungsten powder to lower the purity of the tungsten powder.

The surfactant of this example is a polyoxyalkylene alkyl ether, a polyoxyalkylene alkylphenol ether, a polyoxyalkylene arylphenol ether, a polyoxyalkylene fatty acid ester, a polyoxyalkylene sorbitan fatty acid ester, a polyoxyalkylene alkyl Amines, sorbitan fatty acid esters, alkyl alcohol amines, and aryl alcohol amines, but is not limited thereto.

More specifically, in the cleaning composition of this embodiment, the surfactant may include polyoxyalkylene alkyl ethers, sorbitan fatty acid esters, and polyoxyalkylene sorbitan fatty acid esters, preferably polyoxyalkylene alkyl ethers, Fatty acid esters and polyoxyalkylene sorbitan fatty acid esters at a weight ratio of 1: 0.5 to 2: 0.5 to 2.

In this embodiment, the polyoxyalkylene alkyl ether, the sorbitan fatty acid ester and the polyoxyalkylene sorbitan fatty acid ester are mixed at a weight ratio of 1: 0.5 to 2: 0.5 to 2, preferably 1: 1 to 1: 1 To 2, more preferably 1: 1: 2, the purity of the recovered tungsten powder can be further increased. Particularly, when the same amount of the surfactant is contained in the cleaning composition, the content of the polyoxyalkylene sorbitan fatty acid ester in the polyoxyalkylene alkyl ether, the sorbitan fatty acid ester and the polyoxyalkylene sorbitan fatty acid ester is higher Recovery of high purity tungsten may be possible.

As the polyoxyalkylene alkyl ether of this embodiment, any known substance may be applied, but it may preferably be a polyoxyethylene alkyl ether. More preferably, the polyoxyethylene alkyl ether may be polyoxyethylene lauryl ether, but is not limited thereto.

As the sorbitan fatty acid ester of this embodiment, any known substance may be applied, but it may preferably be a sorbitan monooleate ester.

As the polyoxyalkylene sorbit fatty acid ester of this embodiment, any known substance may be applied, but it may preferably be polyoxyethylene sorbitan monopalmitate.

The solvent of this embodiment can be applied without limitation as long as the surfactant is dissolved and reactivity with the acidic solution of this embodiment is low, and it is preferably, but not limited to, distilled water.

(e) oxidizing the washed tungsten scrap powder to form tungsten oxide powder (50)

In step (e) of this embodiment, the tungsten scrap powder washed in step (d) of the present embodiment is oxidized to form tungsten oxide powder. More specifically, in step (e) of the present embodiment, the tungsten scrap powder washed in step (d) of the present embodiment is heated at about 850 to 950 ° C for about 1 to 3 hours in a gas atmosphere containing oxygen to remove tungsten oxide powder But is not limited thereto.

In the present embodiment, the gas containing oxygen may mean air or a mixed gas of oxygen and an inert gas such as N ₂ , He, or Ar. In addition, the oxygen-containing gas may include hydrogen peroxide, but hydrogen peroxide is not used alone, but may be mixed with an inert gas to be used.

In the step (e) of this embodiment, the tungsten scrap can be heated at 850 to 950 ° C, preferably 860 to 920 ° C, more preferably 880 to 910 ° C.

If the tungsten scrap powder is heated to a temperature lower than 850 ° C, oxidation of the tungsten scrap powder may not occur sufficiently. If the tungsten scrap powder is heated to a temperature higher than 950 ° C, As the oxidation reaction of the tungsten scrap powder having ~ 1000 micrometer progresses explosively, the tungsten scrap powder may be agglomerated to form a single bond or a lump.

The tungsten oxide produced in step (e) of this embodiment may be WO ₂ or WO ₃ , but is not limited thereto.

(f) reducing tungsten oxide powder to form tungsten powder (60)

In step (f) of this embodiment, the tungsten oxide powder formed in step (e) of the present embodiment is reduced to form tungsten powder. More specifically, in step (f) of this embodiment, the tungsten oxide powder formed in step (e) of this embodiment is heated at about 800 to 900 ° C. for about 1 to 3 hours under a gas atmosphere containing hydrogen to form tungsten powder But is not limited thereto.

In this embodiment, the hydrogen-containing gas may be air or a mixed gas of hydrogen and an inert gas such as N ₂ , He or Ar. In the step (f) of this embodiment, the tungsten oxide powder can be heated at 800 to 900 占 폚, preferably 820 to 875 占 폚, and more preferably 840 to 860 占 폚. If the tungsten oxide powder is heated to less than 800 ° C., the reduction of the tungsten oxide may not be sufficiently performed. If the tungsten oxide powder is heated to a temperature exceeding 900 ° C., the tungsten powder may aggregate to form a single bond or a lump There may be a problem.

This embodiment (f) step, sikimyeo reducing the tungsten oxide powder, WO ₃ in more detail the embodiment (f) phase present is reduced to WO _2.9, the WO _2.9 is reduced to WO _2.72, the WO _2.72 is WO ₂ , And the WO ₂ is reduced to W, whereby tungsten powder can be finally obtained. In this case, the particle diameter of the tungsten powder recovered through the step (f) may be 2 to 15 micrometers, but is not limited thereto.

Hereinafter, a method of recycling a tungsten scrap formed with a metal coating layer according to the present invention will be described in detail through examples, comparative examples, and experimental examples. These embodiments are only for illustrating the present invention, and thus the scope of the present invention is not construed as being limited by these embodiments.

[ Example ]

Example  1 to 3

Tungsten scrap deposited with aluminum generated during the manufacturing and disposal of aluminum-deposited tungsten filaments was prepared.

5% sodium hydroxide solution was added to the tungsten scrap in which the aluminum was deposited in the reactor 1 so that the tungsten scrap deposited with aluminum was immersed in the reactor 1, and then stirred (150-400 rpm) while heating at 90 ° C for 1 hour. , And washed with distilled water. (b) Next, it was pulverized with a jaw crusher and a ball mill so as to have an average particle size of about 90 micrometers (± 5 micrometers) to form a tungsten scrap powder. (c) 1% nitric acid solution was added to the reactor 2 so that the tungsten scrap powder and the tungsten scrap powder were immersed in the reactor 2, and then stirred (150-400 rpm) while heating to 60 ° C for 1 hour. (d) After removing the 1% nitric acid solution from the reactor 2, a cleaning composition consisting of 30 wt% of a surfactant (weight ratio in Table 1 below) and 70 wt% of distilled water was charged into the reactor 2 so that the tungsten scrap powder was locked, The scrap powder was washed.

(e) The washed tungsten scrap powder was charged into a continuous furnace, and air containing oxygen (5%) was continuously flowed therein at a rate of 5 L / min while continuously heating it from room temperature to about 900 ° C, Thereby forming a tungsten oxide powder. (f) A tungsten oxide powder was continuously charged, and a mixed gas in which hydrogen (5%) and the remaining amount of nitrogen were continuously mixed was continuously fed at a rate of 5 L / min while being heated to about 850 캜 at room temperature. By maintaining for about 2 hours, a tungsten powder was obtained.

In this case, the surfactant was mixed in the weight ratio shown in Table 1 below, and tungsten powder was obtained in the same manner as in Examples 1 to 3 except that the surfactant mixed in the weight ratio shown in the following Table 1 was used.

In addition to the above (a) to (f), a separate treatment for obtaining a tungsten powder may be further included, which is omitted in the above description.

Weight ratio Example  One Example  2 Example  3 Polyoxyethylene alkyl ether One One One Sorbitan monooleate ester One One One Polyoxyethylene sorbitan monopalmitate 0.5 One 2

Example  4

Tungsten powder was obtained in the same manner as in Example 3, except that the 5% sodium hydroxide solution was treated and the ultrasonic treatment was performed under the conditions of a frequency of 32 kHz and an amplitude of 25 탆.

[ Comparative Example ]

Comparative Example  One

Tungsten powder was obtained in the same manner as in Example 1, except that the step (a) of treating the 5% sodium hydroxide solution was omitted.

Comparative Example  2

Tungsten powder was obtained in the same manner as in Example 1, except that step (c) of treating 1% nitric acid solution was omitted.

Comparative Example  3

Tungsten powder was obtained in the same manner as in Example 1 except that the step (d) of washing with a cleaning composition containing a surfactant and distilled water was omitted.

Comparative Example  4 to 6

Tungsten powder was obtained in the same manner as in Example 1, except that the surfactant of Table 2 was used.

Weight ratio Comparative Example  4 Comparative Example  5 Comparative Example  6 Polyoxyethylene alkyl ether One One One Sorbitan monooleate ester One One One Polyoxyethylene sorbitan monopalmitate 0.1 3 4

Comparative Example  7

The procedure of Example 1 was repeated except that the tungsten scrap powder had a particle size of 60 micrometers.

Comparative Example  8

The procedure of Example 1 was repeated except that the particle size of the tungsten scrap powder was 120 micrometers in the step (b).

Comparative Example  9

Tungsten powder was obtained in the same manner as in Example 3, except that the 5% sodium hydroxide solution was treated and the ultrasonic wave treatment was performed under the conditions of a frequency of 40 kHz and an amplitude of 25 占 퐉.

Comparative Example  10

Tungsten powder was obtained in the same manner as in Example 1 except that a cleaning composition containing 10% by weight of a surfactant and 90% by weight of distilled water was used.

Comparative Example  11

Tungsten powder was obtained in the same manner as in Example 1, except that a cleaning composition containing 50% by weight of a surfactant and 50% by weight of distilled water was used.

[ Experimental Example ]

Experimental Example  One

The tungsten powders obtained in Examples 1 to 4 and Comparative Examples 1 to 11 were subjected to ICP-OES (iCAP 6000 Series, manufactured by Thermo, Type: Plasma, RF Generator: 27.12 MHz solid state generator ), And the results are shown in Table 3 below.

In Table 3, tungsten purity means the tungsten content in the result of the analysis, and the test result of Example 4 is shown in Fig .

Tungsten purity Tungsten purity Example 1 95.811% Comparative Example 5 89.437% Example 2 96.794% Comparative Example 6 91.736% Example 3 97.562% Comparative Example 7 89.418% Example 4 99.631% Comparative Example 8 86.447% Comparative Example 1 57.113% Comparative Example 9 92.764% Comparative Example 2 68.469% Comparative Example 10 83.059% Comparative Example 3 78.274% Comparative Example 11 87.314% Comparative Example 4 86.145%

Table 3 shows that the tungsten purity of the examples is significantly better than that of the comparative example. In particular, in Examples 1 to 4, the purity was as high as 95% or more, and in particular, when the ultrasonic treatment was carried out, the purity was the highest at 99% or more.

In addition, it can be confirmed that the purity of tungsten is remarkably low in Comparative Examples 1 to 3 in which basic solution treatment, acidic solution treatment, and cleaning treatment using a cleaning composition are not performed.

Also, as in this embodiment, even if polyoxyalkylene alkyl ether, sorbitan fatty acid ester, and polyoxyalkylene sorbitan fatty acid ester are contained, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, and polyoxyalkylene sorbitan It can be confirmed that the purity of tungsten is lowered even when the fatty acid ester is not contained at a weight ratio of 1: 0.5 to 2: 0.5 to 2.

Comparing Example 4 and Comparative Example 9 in which the ultrasonic treatment was performed, it can be confirmed that the tungsten purity is lowered in the case of Comparative Example 9 in which the ultrasonic treatment was performed at a frequency outside the range suggested in the present invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. You will understand. It is therefore to be understood that the embodiments described above are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

Claims (9)

(a) treating the tungsten scrap with a basic solution;
(b) pulverizing the tungsten scrap treated with the basic solution to form tungsten scrap powder;
(c) treating the tungsten scrap powder with an acidic solution;
(d) washing the tungsten scrap powder treated with the acid solution with a cleaning composition comprising a surfactant and a solvent;
(e) oxidizing the washed tungsten scrap powder to form tungsten oxide powder; And
(f) reducing the tungsten oxide powder to form tungsten powder,
The tungsten scrap of the step (a) may be a metal coating layer,
Wherein the acidic solution comprises at least one selected from the group consisting of a hydrochloric acid solution, a nitric acid solution and a sulfuric acid solution,
Wherein the surfactant comprises a polyoxyalkylene alkyl ether, a sorbitan fatty acid ester, and a polyoxyalkylene sorbitan fatty acid ester.
The method according to claim 1,
In the step (a)
A method for recycling a tungsten scrap formed with a metal coating layer, characterized in that ultrasonic treatment is performed.
3. The method of claim 2,
In the step (a)
Wherein the ultrasonic treatment is carried out at a frequency of 30 to 35 kHz and an amplitude of 20 to 30 占 퐉.
The method according to claim 1,
The metal coating layer
Wherein the metal coating layer is an aluminum coating layer.
The method according to claim 1,
In the step (b)
Wherein the tungsten scrap powder has a particle size of 80 to 100 micrometers.
The method according to claim 1,
The cleaning composition
Wherein the cleaning composition comprises 15 to 40% by weight of a surfactant based on the total weight of the cleaning composition and a residual solvent.
The method according to claim 1,
The surfactant
A method for recycling a tungsten scrap comprising a metal coating layer, wherein the metal coating layer comprises a polyoxyalkylene alkyl ether, a sorbitan fatty acid ester, and a polyoxyalkylene sorbitan fatty acid ester in a weight ratio of 1: 0.5 to 2: 0.5 to 2.
The method according to claim 1,
The basic solution
Wherein the metal coating layer comprises at least one selected from the group consisting of sodium hydroxide (NaOH) solution, calcium hydroxide (Ca (OH) ₂ ) solution and potassium hydroxide (KOH) solution.
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