KR101919997B1 - Method for recovering germanium from optical fiber - Google Patents

Abstract

Disclosed is a method to collect germanium from optical fiber, capable of efficiently collecting germanium from optical fiber of a waste optical cable. According to one embodiment of the present invention, the method to collect germanium from optical fiber comprises: a step of pulverizing optical fiber containing SiO_2 and GeO_2 to acquire a pulverized matter; a step of inputting Na_2CO_3 to the pulverized matter and performing pulverization to acquire a mixture; a step of reacting SiO_2 and Na_2CO_3 contained in the mixture to acquire a first reactant, from which Si is separated, from at least a part of SiO_2 contained in the mixture; a step of reacting Si_O2 contained in the first reactant with NaOH to acquire a second reactant, from which Si is separated, from SiO_2 contained in the first reactant; a step of reacting the second reactant with any one of HCl, H_2SO_4, and HNO_3 to acquire a third reactant; and a step of collecting Ge from the third reactant.

Description

METHOD FOR RECOVERING GERMANIUM FROM OPTICAL FIBER BACKGROUND OF THE INVENTION [0001]

The present invention relates to a method for recovering germanium from an optical fiber.

As the demand for data communication increases rapidly and as the information and communication technology develops, it is difficult to satisfy the demand for information communication that needs to transmit various types of information such as voice, data, and video with the existing coaxial cable. As a result, the use of optical cables for transmitting / receiving signals by light is increasing rapidly. In addition, the submarine cables connecting the countries and the continents as well as the wired communication networks of each country are mostly composed of optical cables.

On the other hand, such an optical cable includes an optical fiber for transmitting light. Specifically, the optical fiber is composed of a core for passing light, a cladding for guiding light to pass therethrough, and a coating layer surrounding them. At this time, the core may be composed mainly of silicon dioxide (SiO ₂ ) and germanium dioxide (GeO ₂ ), and the cladding may be composed of silicon dioxide (SiO ₂ ) as a main component. As a result, the core can have a refractive index higher than that of the cladding by germanium (Ge), so that the light incident on the front end of the core can be transmitted to the rear end of the core while being totally reflected at the boundary between the core and the cladding.

On the other hand, germanium (Ge) contained in the core is not only a rare metal having a high price of more than 1,300,000 won per 1 kg, but also a germanium mine in the domestic market. Therefore, the germanium contained in the core is imported, There is a need for a method to do this. To cope with this, germanium (Ge) is recovered from the core by chlorination, fractional distillation, hydrolysis and reduction of the optical fiber, or the silicon (Si) contained in the core is completely melted by introducing and heating the optical fiber into a high concentration acid solution , And germanium (Ge) are eluted and recovered.

However, in such conventional methods, much time and energy are consumed in the process of fractionating an optical fiber, and a great amount of time and energy are consumed in the process of completely dissolving a large amount of silicon (Si) contained in the core.

Therefore, there is a need for a research and development of a method for efficiently recovering expensive resources such as germanium (Ge) from an optical fiber of an abandoned light cable.

Korean Registered Patent No. 10-1589049 (registered on January 21, 2016)

Embodiments of the present invention have been proposed in view of the problems of the prior art as described above, and it is an object of the present invention to provide a method for efficiently recovering expensive resources such as germanium (Ge) from an optical fiber of a cable.

According to an aspect of the present invention, there is provided a method for producing a pulverized product, comprising the steps of pulverizing an optical fiber containing silicon dioxide (SiO ₂ ) and germanium dioxide (GeO ₂ ) to obtain a pulverized product, adding sodium carbonate (Na ₂ CO ₃ ) (Si) from at least a part of the silicon dioxide (SiO ₂ ) contained in the mixture by reacting silicon dioxide (SiO ₂ ) and sodium carbonate (Na ₂ CO ₃ ) contained in the mixture to obtain a mixture (Si) from the silicon dioxide (SiO ₂ ) contained in the first reactant by reacting the silicon dioxide (SiO ₂ ) and sodium hydroxide (NaOH) contained in the first reactant to obtain a first reactant, Obtaining germanium (Ge) from the third reactant, obtaining a separated second reactant, reacting the second reactant with an acid solution to obtain a third reactant, and recovering germanium (Ge) from the third reactant. There are ways that can be provided

Also, the step of obtaining the first reactant may be performed at a temperature of 400 ° C or more and 900 ° C or less for 1 hour in a reactor furnished with a nitrogen (N ₂ ) atmosphere.

Also, the step of obtaining the second reactant may be carried out in a ball mill at a temperature of 0 ° C or more and less than 900 ° C for 1 hour.

In addition, the step of obtaining the third reactant may include: reacting the silicon trioxide (SiO ₃ ) of the second reactant with the acid solution to gel the silicon oxynitride (Si (OH) ₄ ) (Ge) is dissolved in the acid solution, and the acid solution in which the silicon tetraoxide (Si (OH) ₄ ) and germanium (Ge) are dissolved is separated, (HCl), sulfuric acid (H ₂ SO ₄ ), and nitric acid (HNO ₃ ).

Further, in the step of obtaining the first reactant, a chemical reaction according to the following chemical formula 1 may occur between silicon dioxide (SiO ₂ ) and sodium carbonate (Na ₂ CO ₃ ) contained in the mixture.

[Chemical Formula 1]

SiO ₂ + Na ₂ CO ₃ = Na ₂ SiO ₃ + CO ₂

Further, in the step of obtaining the second reactant, a chemical reaction according to the following formula 2 may occur between silicon dioxide and sodium hydroxide contained in the first reactant.

(2)

_{SiO 2 + 2NaOH = Na 2 SiO} 3 + H 2 O

Further, the step of recovering germanium (Ge) from the third reactant may be carried out by any one of a substitutional precipitation method, an electrolytic extraction method and a solvent extraction method.

The method of recovering germanium from the optical fiber according to the embodiments of the present invention has the effect of efficiently recovering expensive resources such as germanium (Ge) from the optical fiber of the abandoned light cable.

1 is a flowchart showing a method of recovering germanium from an optical fiber according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, configurations and operations according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE INVENTION The following description is one of many aspects of the claimed invention and the following description may form part of the detailed description of the invention.

However, the detailed description of known configurations or functions in describing the present invention may be omitted for clarity.

While the invention is susceptible to various modifications and its various embodiments, it is intended to illustrate the specific embodiments and the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Terms including ordinals such as first, second, etc. may be used to describe various elements, but the elements are not limited by such terms. These terms are used only to distinguish one component from another.

It is to be understood that when an element is referred to as being "coupled" or "connected" to another element, it may be directly coupled or connected to the other element, .

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

Hereinafter, a method for recovering germanium from an optical fiber according to an embodiment of the present invention will be described with reference to FIG.

Referring to FIG. 1, a method of recovering germanium from an optical fiber according to an embodiment of the present invention includes grinding an optical fiber containing silicon dioxide (SiO ₂ ) and germanium dioxide (GeO ₂ ) ), sodium carbonate in pulverized (Na ₂ CO ₃₎ the charge and mixed to the silicon dioxide included in the step (S200), the mixture to give a mixture (SiO ₂₎ with sodium carbonate (Na ₂ CO ₃₎ and the reaction by including in the mixture a by reaction of step (S300), the silicon dioxide contained in the first reactant (SiO ₂₎ and sodium hydroxide (NaOH) to at least obtain a first reaction product of silicon (Si) is separated from the portion of the silicon dioxide (SiO ₂₎ comprising the steps of: by one reaction product of silicon dioxide (SiO ₂₎ from silicon (Si) is to obtain the separated second reaction product (S400), the reaction and the second reaction the acid solution containing the resultant third reaction (S500) And recovering germanium (Ge) from the third reactant Step S600.

Meanwhile, in this embodiment, sodium carbonate (Na ₂ CO ₃ ) is added to a pulverized product obtained by pulverizing a single mode optical fiber composed of silicon dioxide (SiO ₂ ) and germanium dioxide (GeO ₂ ) And then recovering germanium (Ge) from the pulverized material will be described as an example, but the spirit of the present invention is not necessarily limited thereto.

A method of recovering germanium from an optical fiber according to an embodiment of the present invention includes grinding a multimode optical fiber composed of silicon dioxide (SiO _{2 )} , germanium dioxide (GeO ₂ ), terium (Te), and gallium (Ga) (Si) can be used to recover germanium (Ge) contained in the pulverized product after first separating silicon (Si) from the pulverized product by introducing sodium carbonate (Na ₂ CO ₃ ) into the pulverized product, (Na ₂ CO ₃ ) may be added to the pulverized product obtained by pulverizing the silicon-metal alloy, and then the silicon (Si) may be firstly separated from the pulverized product, and then the metal component contained in the pulverized product may be recovered.

Hereinafter, a method of recovering germanium from an optical fiber according to an embodiment of the present invention will be described separately for each step.

The pulverized material  ( S100 )

First, the optical fiber of the abandoned light cable is prepared. At this time, the optical fiber may be directly separated from the abandoned light cable by cutting, cutting, pressing, heating and dissolving the abandoned light cable, or an optical fiber already separated from the abandoned light cable may be purchased and used. Here, the optical fiber may be any one of a multimode optical fiber and a single mode optical fiber having a core, a cladding surrounding the core, and a coating layer surrounding the core and the cladding. Hereinafter, for convenience of explanation, a single-mode optical fiber in which a coating layer has been previously removed through a burning process will be described as an example.

The separated optical fiber is pulverized as described above. Specifically, a plurality of balls (steel balls) are put into a cylinder, and the ball is put into a ball mill for crushing the optical fiber by an impact caused by motion of a ball (ball), and the ball is rotated at a high speed for 1 hour, Mu] m.

Meanwhile, the pulverized product of the optical fiber from the grinding step (S100) may include a germanium dioxide (GeO ₂₎ core and cladding from the crushing of the silicon dioxide (SiO ₂₎ and the optical fiber cladding of the optical fiber from the grinding.

To obtain a mixture S200 )

The pulverized material and sodium carbonate (Na ₂ CO ₃ ) are put into a ball mill at a mass ratio of 1: 3. Then, the ball mill is rotated at a high speed for 24 hours to obtain a mixture of the pulverized product and sodium carbonate (Na ₂ CO ₃ ).

At this time, the mixture may include silicon dioxide (SiO ₂ ), germanium dioxide (GeO ₂ ), and sodium carbonate (Na ₂ CO ₃ ).

Obtaining a first reactant S300 )

This step S300 is a step provided for separating silicon (Si) of silicon dioxide (SiO ₂ ) by reacting with silicon dioxide (SiO ₂ ) and sodium carbonate (Na ₂ CO ₃ ) contained in the mixture.

Specifically, the mixture is withdrawn from the ball mill and introduced into the reactor. Then, an inert gas such as nitrogen (N ₂ ) gas is introduced into the reactor to form a nitrogen (N ₂ ) gas atmosphere in the reactor, and then the reactor is heated at 400 ° C. for 1 hour.

At this time, a chemical reaction may occur between silicon dioxide (SiO ₂ ) and sodium carbonate (Na ₂ CO ₃ ) contained in the mixture, and a chemical reaction formula between silicon dioxide (SiO ₂ ) and sodium carbonate (Na ₂ CO ₃ ) 1.

[Chemical Formula 1]

SiO ₂ + Na ₂ CO ₃ = Na ₂ SiO ₃ + CO ₂

Referring to Equation 1, silicon dioxide (SiO ₂ ) contained in the mixture reacts with sodium carbonate (Na ₂ CO ₃ ) to produce sodium metasilicate (Na ₂ SiO ₃ ) and produces carbon dioxide (CO ₂ ) Able to know.

On the other hand, only silicon dioxide (SiO ₂ ) in the mixture can react with sodium carbonate (Na ₂ CO ₃ ) at a temperature of 400 ° C. will be described with reference to Table 1 below. Table 1 is a table showing reaction temperature calculation results according to the formula (1).

T (C) Delta H (kcal) Delta S (cal / k) Delta G (kcal) K Log (K) 0.000 20.753 36.238 10.855 2.062E-009 -8.686 100,000 20.600 35.765 7.255 5.632E-005 -4.249 200,000 20.340 35.156 3.706 1.941E-002 -1.712 300,000 19.824 34.176 0.236 8.129E-001 -0.090 400,000 18.922 32.735 -3.114 1.026E + 001 1.011 500,000 17.991 31.423 -6.304 6.056E + 001 1.782 600,000 17.427 30.743 -9.417 2.276E + 002 2.357 700,000 16.993 30.274 -12.469 6.316E + 002 2.800 800,000 16.366 29.663 -15.467 1.413E + 003 3.150 900,000 8.054 22.242 -18.039 2.296E + 003 3.361 1000,000 7.429 21.730 -20.237 2.980E + 003 3.474

Referring to Table 1, it can be seen that the reaction occurs spontaneously from 400 ° C. at which the value of the Gibbs free energy change, which is the value of the Delta G value, becomes negative. As the negative value increases, the reaction product is thermodynamically stable have. In other words, when the temperature of the reaction not less than 400 ℃, silicon dioxide (SiO ₂₎ and sodium carbonate (Na ₂ CO ₃₎ is silicon (Si) in the up and the reaction of silicon dioxide (SiO ₂₎ between the meta-sodium silicate (Na ₂ SiO ₃ ), and silicon (Si) is actively separated from silicon dioxide (SiO ₂ ).

However, the inventors of the present invention have repeatedly conducted experiments and studies to find that when the temperature of the reactor is 900 ° C. and 1000 ° C., the Delta G value is negative, but at this temperature, not only silicon dioxide (SiO ₂ ) (GeO ₂ ) also reacts with sodium carbonate (Na ₂ CO ₃ ). Therefore, when the temperature of the reactor is higher than 900 ° C, the separation efficiency of silicon (Si) of silicon dioxide (SiO ₂ ) contained in the mixture may be lowered. Therefore, It is better to limit.

On the other hand, after the reaction of the formula (1) is completed, reaction products and mixture residues produced by the reaction of silicon dioxide (SiO ₂ ) and sodium carbonate (Na ₂ CO ₃ ) contained in the mixture may remain in the reaction furnace. Here, for convenience of explanation, the reaction product remaining in the reactor and the residue of the mixture will be referred to as a first reactant. Here, the residue of the mixture means a mixture remaining in the mixture used in the chemical reaction of Chemical Formula 1, so that the composition of the first reaction product may vary depending on the degree of chemical reaction of Chemical Formula 1.

Obtaining a second reactant S400 )

The step (S400) is provided for after the reaction of silicon dioxide (SiO ₂₎ and sodium carbonate in the previous step _{(S300) (Na 2 CO 3} ), separating the silicon (Si) of silicon dioxide (SiO ₂₎ that may be remaining .

Specifically, after withdrawing the first reactant from the reaction furnace, it is introduced into a ball mill. In addition, sodium hydroxide (NaOH) is added to the ball mill. Then, the ball mill is rotated at a high speed for 1 hour at room temperature to increase the contact area between the first reactant and sodium hydroxide (NaOH).

At this time, a chemical reaction may occur between silicon dioxide (SiO ₂ ) and sodium hydroxide (NaOH) contained in the first reactant, and a chemical reaction formula between silicon dioxide (SiO ₂ ) and sodium hydroxide (NaOH) same.

(2)

_{SiO 2 + 2NaOH = Na 2 SiO} 3 + H 2 O

Referring to Equation 2, silicon dioxide (SiO ₂ ) contained in the first reactant reacts with sodium hydroxide (NaOH) to produce sodium metasilicate (Na ₂ SiO ₃ ) and water (H ₂ O) .

Table 2 below is a table showing reaction temperature calculation results according to formula (2).

T (C) Delta H (kcal) Delta S (cal / k) Delta G (kcal) K Log (K) 0.000 -21.848 -2.541 -21.154 8.443E + 016 16.927 100,000 -19.850 4.473 -21.519 4.023E + 012 12.605 200,000 -19.478 5.369 -22.018 1.483E + 010 10.171 300,000 -19.330 5.657 -22.572 4.052E + 008 8.608 400,000 -21.742 1.532 -22.773 2.479E + 007 7.394 500,000 -20.981 2.584 -22.979 3.135E + 006 6.496 600,000 -20.300 3.415 -23.282 6.730E + 005 5.828 700,000 -19.207 4.600 -23.683 2.085E + 005 5.319 800,000 -18.021 5.758 -24.201 8.492E + 004 4.929 900,000 -17.252 6.426 -24.791 4.157E + 004 4.619 1000,000 -15.932 7.506 -25.488 2.375E + 004 4.376

Referring to Table 2, it can be seen that the reaction occurs spontaneously due to the fact that the value of Delta G becomes negative from 0 ° C, and the reaction product is thermodynamically stable as the negative value increases. In other words, a reaction occurs between silicon dioxide (SiO ₂ ) and sodium hydroxide (NaOH) at room temperature and the silicon (Si) of silicon dioxide (SiO ₂ ) is changed to sodium metasilicate (Na ₂ SiO ₃ ) ₂ ), silicon (Si) is actively separated.

In addition, the inventor of the present invention has repeatedly conducted experiments and studies to find that the reaction between silicon dioxide (SiO ₂ ) and sodium hydroxide (NaOH) does not occur when the internal temperature of the ball mill is lower than 0 ° C, (Ge ₂ O ₃ ) reacts with sodium hydroxide (NaOH) as well as silicon dioxide (SiO ₂ ). Therefore, it is preferable to limit the internal temperature of the ball mill to 0 ° C or higher and lower than 900 ° C.

On the other hand, after the reaction of formula (2) is completed, a small amount of silicon dioxide (SiO ₂ ) contained in the first reactant may react with sodium hydroxide (NaOH) to leave the reaction product and the first reactant residue have. Here, for convenience of explanation, the reaction product existing in the ball mill and the first reactant residue will be referred to as a second reactant. Here, the first reactant residue refers to the first reactant remaining in the first reactant, which is used in the chemical reaction of Chemical Formula 2, so that the composition of the second reactant may vary according to the chemical reaction of Chemical Formula 2.

Obtaining a third reactant S500 )

The second reactant is withdrawn from the ball mill and then charged into the reactor. Further, 50 ml of an acid solution such as hydrochloric acid (HCl) solution is added to the reaction tank. Next, the reaction tank is heated at a temperature of 80 DEG C for 30 minutes.

In this process, the germanium (Ge) of germanium (GeO ₂ ) contained in the second reactant may be dissolved in the hydrochloric acid (HCl) solution, and between the hydrochloric acid (HCl) solution and sodium metasilicate (Na ₂ SiO ₃ ) A chemical reaction such as the chemical formula (3) can occur.

(3)

Na ₂ SiO ₃ + H ₂ O + 2HCl = [Si (OH) ₄ ] _solid + 2NaCl

(Si (OH) ₄ ) and sodium chloride (sodium hydroxide) reacted with a hydrochloric acid (HCl) solution to solidify (gel) the sodium silicate (SiO ₃ ) component of sodium metasilicate (Na ₂ SiO ₃ ) (NaCl). ≪ / RTI >

On the other hand, after the reaction of the formula (3) is completed, the reaction product and the second reactant residue resulting from the reaction of the second reactant and the hydrochloric acid (HCl) solution may remain in the reaction tank. Here, for convenience of explanation, the reaction product present in the reaction tank and the second reaction product residue will be referred to as a third reaction product. Here, the second reactant residue refers to the second reactant remaining in the second reactant, which is used in the chemical reaction of Chemical Formula 3, and the composition of the third reactant may vary depending on the chemical reaction of Chemical Formula 2.

In the present embodiment, the acid solution is a hydrochloric acid (HCl) solution for convenience of explanation. However, the present invention is not limited thereto, and the acid solution may be sulfuric acid (H ₂ SO ₄ ) And nitric acid (HNO ₃ ).

From the third reactant germanium ( Ge (Step < RTI ID = 0.0 > S600 )

The third reactant is introduced into a separation vessel to separate silicon tetraoxide (Si (OH) ₄ ) and germanium (Ge).

Specifically, the third reaction material is filtered using a filter provided under the separation tank, for example, acid-resistant filter paper. At this time, silicon oxide (Si (OH) ₄ ) having gel state is filtered by acid-resistant filter paper, and hydrochloric acid (HCl) solution in which germanium (Ge) is dissolved passes through acid-resistant filter paper.

On the other hand, germanium (Ge) dissolved in a hydrochloric acid (HCl) solution passed through an acid-resistant filter paper is precipitated by a substitutional precipitation method as an example.

Specifically, an element having a reduction potential value between silicon (Si) and germanium (Ge), such as iron (Fe), zinc (Zn), tin (Sn), cobalt (Co) And then germanium (Ge) is precipitated from a hydrochloric acid (HCl) solution. However, the spirit of the present invention is not limited thereto, and germanium (Ge) dissolved in a hydrochloric acid (HCl) solution may be recovered through an electrolytic extraction method or a solvent extraction method.

The method of recovering germanium from the optical fiber having the above-described structure is a method of recovering germanium from the optical fiber of the abandoned light cable and / or the silicon dioxide (SiO ₂ ) contained in the silicon (Si) by changing the silicon (Si) as a meta-sodium silicate (Na ₂ SiO _3), first separation, germanium (Ge) a number of times as, germanium can be reduced compared with the time and energy consumed in recovering (Ge) in the conventional, depending .

Further, since sodium metasilicate (Na ₂ SiO ₃ ) produced in the process of recovering germanium (Ge) can be utilized in other industrial fields, there is an economic effect.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. For example, a person skilled in the art can change the material, size and the like of each constituent element depending on the application field or can combine or substitute the embodiments in a form not clearly disclosed in the embodiments of the present invention, Of the range. Therefore, it should be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive, and that such modified embodiments are included in the technical idea described in the claims of the present invention.

Claims (7)

Pulverizing an optical fiber containing silicon dioxide (SiO ₂ ) and germanium dioxide (GeO ₂ ) to obtain a pulverized product;
Adding sodium carbonate (Na ₂ CO ₃ ) to the pulverized product and mixing to obtain a mixture;
Reacting the silicon dioxide (SiO ₂ ) and sodium carbonate (Na ₂ CO ₃ ) contained in the mixture to obtain a first reactant in which silicon (Si) is separated from at least a portion of the silicon dioxide (SiO ₂ ) step;
Incorporating a sodium hydroxide (NaOH) to the first reaction product said first reaction product of silicon dioxide (SiO ₂₎ and silicon (Si) from the silicon dioxide (SiO ₂₎ contained in the first reaction by reacting with sodium hydroxide contained in the To obtain a separated second reactant;
Adding an acid solution to the second reactant to react the second reactant with the acid solution to obtain a third reactant in the second reactant that corresponds to the remainder remaining in the reaction with the acid solution; And
Recovering germanium (Ge) from the third reactant through any one of a displacement deposition method, an electrolytic extraction method, and a solvent extraction method.
A method for recovering germanium from an optical fiber. The method according to claim 1,
The step of obtaining the first reactant comprises:
(N ₂ ) atmosphere at a temperature of 400 ° C. or more and less than 900 ° C. for 1 hour,
A method for recovering germanium from an optical fiber. The method according to claim 1,
The step of obtaining the second reactant comprises:
Which is carried out in a ball mill at a temperature of not lower than 0 DEG C but not higher than 900 DEG C for 1 hour,
A method for recovering germanium from an optical fiber. The method according to claim 1,
The step of obtaining the third reactant comprises:
Wherein the silicon trioxide (SiO ₃ ) of the second reactant reacts with the acid solution and is gelled with silicon tetraoxide (Si (OH) ₄ ), and the germanium (Ge) of the second reactant is dissolved in the acid solution; And
Separating any one of said acid solutions in which silicon tetraoxide (Si (OH) ₄ ) and germanium (Ge) have been dissolved,
The acid solution,
(HCl), sulfuric acid (H ₂ SO ₄ ), and nitric acid (HNO ₃ ).
A method for recovering germanium from an optical fiber. The method according to claim 1,
In the step of obtaining the first reactant, a chemical reaction between the silicon dioxide (SiO ₂ ) and sodium carbonate (Na ₂ CO ₃ )
A method for recovering germanium from an optical fiber.
[Chemical Formula 1]
SiO ₂ + Na ₂ CO ₃ = Na ₂ SiO ₃ + CO ₂ The method according to claim 1,
Wherein in the step of obtaining the second reactant, a chemical reaction according to the following formula (2) takes place between the silicon dioxide and sodium hydroxide contained in the first reactant,
A method for recovering germanium from an optical fiber.
(2)
_{SiO 2 + 2NaOH = Na 2 SiO} 3 + H 2 O delete

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