Method for recovering high-quality germanium concentrate from scrapped glass optical fibers

Abstract

The invention discloses a method for recovering high-quality germanium concentrate from scrapped glass optical fibers, and belongs to the technical field of rare metal recovery. Crushing and screening the scrapped glass optical fiber to obtain optical fiber powder; the optical fiber powder and NaOH or Na2CO3 are uniformly mixed, the molar ratio of NaSi to NaGe of the mixture is (3-6): 1, and roasting is conducted for 2-4 h at the temperature of 500-800 DEG C; mixing the roasted material with water according to a solid-to-liquid ratio of 1: (4-10), heating to 50-100 DEG C, stirring and dissolving to generate a leaching solution; after filtering, feeding the filtered clear liquid into a spraying device filled with adsorption resin from an inlet of the device at the temperature of 5-40 DEG C and the flow speed of 5-50mm / min; and feeding an inorganic acid desorption agent into a spraying device from an outlet of the device at the temperature of 50-80 DEG C and the flow speed of 10-100mm / min, collecting the desorbed liquid, and adding water which is 3-5 times of the theoretical hydrolysis amount to obtain the germanium concentrate. The method is simple in technological process, low in energy consumption and high in metal direct recovery rate, the germanium mass content of the enriched germanium concentrate is larger than 40%, the germanium recovery rate is larger than 92%, the main component obtained after germanium recovery is sodium silicate, and multiple benefits of resources, economy, environment and the like are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of rare metal recovery, and particularly relates to a method for recovering high-quality germanium concentrate from waste glass optical fibers. Background Art

[0002] Germanium and its compounds are widely used in the fields of electronics industry, infrared optics, optical fiber communication, chemical catalysts, etc.

[0003] Optical fiber communication is the foundation of the information age. Adding germanium to optical fibers can greatly reduce the transmission loss of the fibers and increase the refractive index. High-purity GeCl4 and SiCl4 are filled into a quartz tube in a certain proportion, and a GeO2 film layer is formed on the tube wall at 1300 °C. The rod is made by chemical vapor deposition, and then the optical fiber can be obtained by melting and drawing. Currently, the germanium consumption in the germanium-doped optical fiber industry accounts for more than 30% of the total global germanium demand. Optical fibers are the largest application field of germanium. Since optical fibers need to be replaced every 15 years, the amount of waste optical fibers is increasing year by year.

[0004] Currently, the methods for treating waste optical fibers are pyrometallurgy and hydrometallurgy. The pyrometallurgy process is to melt the waste optical fiber material at high temperature and then introduce a reducing agent for high-temperature reduction. Germanium volatilizes into the flue gas and is collected. This process has the disadvantages of low direct recovery rate of germanium, long process flow, and large investment; the hydrometallurgy process is to crush the glass optical fiber and then add HF as a solvent. Germanium enters the solution, and then germanium is recovered by extraction or precipitation. This process has the problems of large corrosion of equipment by HF, a large amount of waste liquid generated during the extraction process, many impurities introduced during the precipitation process, and difficult filtration.

[0005] Optical fibers belong to general solid waste. Directly discarding them wastes a large amount of land resources. Based on this, providing a method for treating waste optical fibers, efficiently recovering germanium in the optical fibers, and simultaneously recovering silicon will have great resource and environmental benefits and application and promotion value. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for recovering high-quality germanium concentrate from waste glass optical fibers.

[0007] The purpose of the present invention is achieved as follows: The method for recovering high-quality germanium concentrate from waste glass optical fibers includes the following processes: Crush and screen the waste glass optical fibers to obtain optical fiber powder; Mix the optical fiber powder evenly with NaOH or Na2CO3, and the molar ratio of NaSi to NaGe in the mixture is 3 - 6:1; Roast the mixture at 500 - 800 °C for 2 - 4 h; Mix the roasted material with water according to a solid-liquid ratio of 1:4 - 10, heat to 50 - 100 °C, stir and dissolve to produce a leaching solution; Filter the leaching solution, and at a temperature of 5 - 40°C and a flow rate of 5 - 50 mm / min, feed the obtained filtered clear liquid into the spraying device filled with adsorption resin from the device inlet; At a temperature of 50 - 80°C and a flow rate of 10 - 100 mm / min, feed the inorganic acid desorbent from the device outlet into the spraying device to backwash the germanium-containing resin, and collect the post-desorption liquid; Add water in an amount 3 - 5 times the theoretical hydrolysis amount to the post-desorption liquid to obtain the target germanium concentrate.

[0008] Compared with the prior art, the technical solution of the present invention has the following advantages: 1. Grind and crush the waste glass optical fiber, and the selected particle size range is beneficial to increasing the specific surface area of the material and controlling the generation of agglomeration, effectively improving the accessibility of the reaction reagent and accelerating the reaction rate.

[0009] 2. Adopt alkalization and high-temperature roasting to make silicon and germanium in the optical fiber powder react with alkali to generate soluble sodium silicate, sodium germanate and other substances, which are convenient to enter the leaching solution and improve its leaching efficiency.

[0010] 3. Through the selective adsorption of the resin, germanium in the solution is selectively adsorbed on the resin surface and continuously enriched, while silicon is not adsorbed, thus realizing the separation of silicon and germanium.

[0011] 4. Through the desorption process, germanium is efficiently eluted from the resin, and after enrichment, high-quality germanium concentrate is obtained. The germanium mass content > 40%, the germanium recovery rate > 92%. The main component obtained after recovering germanium is sodium silicate, which can be sold externally and has high economic value.

[0012] 5. The present invention has many advantages such as low energy consumption, short process, small equipment investment, low cost, high direct metal recovery rate, and no generation of "three wastes", realizes the efficient separation of silicon and germanium, takes into account multiple benefits such as resources, economy and environment, and has great popularization and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a flow chart of the technical solution of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] The following further describes the present invention, but does not limit the present invention in any way. Any transformation or replacement based on the teachings of the present invention belongs to the protection scope of the present invention.

[0015] The method for recovering high-quality germanium concentrate from waste glass optical fiber includes the following processes: Crush and screen the waste glass optical fiber to obtain optical fiber powder; Mix the optical fiber powder evenly with NaOH or Na2CO3, and the molar ratio of NaSi to NaGe in the mixture is 3 - 6:1; Roast the mixture at 500 - 800 °C for 2 - 4 h; Mix the roasted material with water at a solid - liquid ratio of 1:4 - 10, heat to 50 - 100 °C, stir and dissolve to produce a leaching solution; Filter the leaching solution, and at 5 - 40 °C, feed the obtained filtered clear liquid into a spraying device filled with adsorption resin from the device inlet at a flow rate of 5 - 50 mm / min; At 50 - 80 °C, feed the inorganic acid desorbent from the device outlet into the spraying device at a flow rate of 10 - 100 mm / min to back - wash the germanium - containing resin, and collect the desorbed solution; Add water which is 3 - 5 times the theoretical hydrolysis amount to the desorbed solution to obtain the target germanium concentrate.

[0016] The scrapped glass optical fiber is generated after the communication optical fiber used in the communication industry is scrapped after a certain service life. The diameter of the scrapped glass optical fiber is 0.1 - 100 mm.

[0017] The germanium mass content of the scrapped glass optical fiber is 0.05 - 0.4%, and the balance is silicon dioxide.

[0018] The crushing and screening are carried out by grinding the scrapped glass optical fiber with a roll crusher and then screening it in a vibrating screen.

[0019] The proportion of the fiber powder with a particle size < 200 mesh is > 90%.

[0020] Both the NaOH and Na₂CO₃ are of industrial - grade purity.

[0021] The stirring speed is 100 - 800 r / min.

[0022] The dissolution time is 30 - 150 min.

[0023] The filtration is carried out by using a suction pump to realize the solid - liquid separation of the leaching solution and obtain the filtered clear liquid.

[0024] The adsorption resin is IRA - 985 resin, and the resin particle size is 1.5 - 4 mm.

[0025] The spraying device is a spraying column, its height is 0.5 - 3 m, and the inner diameter is 5 - 30 mm.

[0026] The residence time of the filtered clear liquid in the spraying device is 20 - 60 min.

[0027] The main component of the inorganic acid desorbent is hydrochloric acid, and the hydrochloric acid concentration is 3 - 10 mol / L.

[0028] The germanium mass content of the germanium concentrate is > 40%, and the germanium recovery rate is > 92%.

[0029] Example 1

[0030] A company collected waste glass optical fibers from the market. The diameter was 8 mm and the germanium mass content was 0.22%. The waste glass optical fibers were ground using a roller crusher and then placed in a vibrating screen for screening to obtain optical fiber powder, among which the proportion of particles with a particle size <200 mesh was 92%.

[0031] The optical fiber powder was mixed evenly with NaOH, and the molar ratio of NaSi to NaGe in the mixture was 3.5:1; the mixture was loaded into a graphite crucible and placed in a muffle furnace, and calcined at 560 °C for 2.5 h.

[0032] The calcined material was loaded into a stirring tank, mixed with water at a solid-liquid ratio of 1:5, heated to 52 °C, stirred at a speed of 100 r / min, and dissolved for 30 min to produce a leaching solution.

[0033] The leaching solution was filtered to obtain a filtered clear liquid. At 6 °C, the obtained filtered clear liquid was fed into a spray pipe filled with IRA-985 resin from the device inlet at a flow rate of 6 mm / min. The resin particle size was 1.5 - 2 mm, and the residence time of the filtered clear liquid in the spray pipe was 55 min.

[0034] Then at 55 °C, a desorbent with a hydrochloric acid concentration of 4 mol / L was fed into the spray pipe from the device outlet at a flow rate of 15 mm / min to backwash the germanium-containing resin, and the desorbed liquid was collected.

[0035] Water three times the theoretical hydrolysis amount was added to the desorbed liquid for hydrolysis. Finally, the obtained germanium concentrate was analyzed for weight and composition. The germanium content was 45% and the germanium recovery rate was 93%.

[0036] Example 2

[0037] A company collected waste glass optical fibers from the market. The diameter was 9 mm and the germanium mass content was 0.25%. The waste glass optical fibers were ground using a roller crusher and then placed in a vibrating screen for screening to obtain optical fiber powder, among which the proportion of particles with a particle size <200 mesh was 91%.

[0038] The optical fiber powder was mixed evenly with NaOH, and the molar ratio of NaSi to NaGe in the mixture was 4:1; the mixture was loaded into a graphite crucible and placed in a muffle furnace, and calcined at 600 °C for 3 h.

[0039] The calcined material was loaded into a stirring tank, mixed with water at a solid-liquid ratio of 1:7, heated to 65 °C, stirred at a speed of 150 r / min, and dissolved for 40 min to produce a leaching solution.

[0040] Filter the leaching solution to obtain a filtered clear solution. At 10 °C, feed the obtained filtered clear solution into a spray pipe filled with IRA-985 resin at a flow rate of 10 mm / min from the device inlet. The resin particle size is 2 - 3 mm, and the residence time of the filtered clear solution in the spray pipe is 50 min.

[0041] Then, at 60 °C, feed a desorbent with a hydrochloric acid concentration of 5 mol / L into the spray pipe from the device outlet at a flow rate of 18 mm / min to backwash the germanium-containing resin, and collect the post-desorption solution.

[0042] Add water four times the theoretical hydrolysis amount to the post-desorption solution for hydrolysis. Finally, conduct weight and composition analysis on the obtained germanium concentrate. The germanium content is 44%, and the germanium recovery rate is 94%.

[0043] Example 3

[0044] A certain company collected scrapped glass optical fibers from the market, with a diameter of 12 mm and a germanium mass content of 0.27%. Grind the scrapped glass optical fibers using a roll crusher, and then place them in a vibrating screen for screening to obtain optical fiber powder, among which the proportion of particles with a size < 200 mesh is 95%.

[0045] Mix the optical fiber powder evenly with Na2CO3. The molar ratio of NaSi to NaGe in the mixture is 5:1; load the mixture into a graphite crucible and place it in a muffle furnace, and roast at 620 °C for 2 h.

[0046] Load the roasted material into a stirring tank, mix it with water at a solid-liquid ratio of 1:4, heat to 70 °C, stir at a speed of 300 r / min, and dissolve for 40 min to produce a leaching solution.

[0047] Filter the leaching solution to obtain a filtered clear solution. At 15 °C, feed the obtained filtered clear solution into a spray pipe filled with IRA-985 resin at a flow rate of 8 mm / min from the device inlet. The resin particle size is 3 - 4 mm, and the residence time of the filtered clear solution in the spray pipe is 60 min.

[0048] Then, at 65 °C, feed a desorbent with a hydrochloric acid concentration of 6 mol / L into the spray pipe from the device outlet at a flow rate of 10 mm / min to backwash the germanium-containing resin, and collect the post-desorption solution.

[0049] Add water four times the theoretical hydrolysis amount to the post-desorption solution for hydrolysis. Finally, conduct weight and composition analysis on the obtained germanium concentrate. The germanium content is 47%, and the germanium recovery rate is 93%.

[0050] Example 4

[0051] A certain company collected waste glass optical fibers from the market. The diameter was 10 mm and the germanium mass content was 0.28%. The waste glass optical fibers were ground using a roller crusher and then placed in a vibrating screen for screening to obtain optical fiber powder, among which the proportion with a particle size <200 mesh was 97%.

[0052] The optical fiber powder was mixed evenly with NaOH, and the molar ratio of NaSi to NaGe in the mixture was 5.5:1. The mixture was loaded into a graphite crucible and placed in a muffle furnace, and calcined at 700 °C for 2 h.

[0053] The calcined material was loaded into a stirring tank, mixed with water at a solid-liquid ratio of 1:8, heated to 85 °C, stirred at a speed of 600 r / min, and dissolved for 120 min to produce a leaching solution.

[0054] The leaching solution was filtered to obtain a filtered clear solution. At 25 °C, the obtained filtered clear solution was fed into a spray pipe filled with IRA-985 resin from the device inlet at a flow rate of 40 mm / min. The resin particle size was 1.5 - 3 mm, and the residence time of the filtered clear solution in the spray pipe was 23 min.

[0055] Then at 75 °C, a desorbent with a hydrochloric acid concentration of 8 mol / L was fed into the spray pipe from the device outlet at a flow rate of 50 mm / min to backwash the germanium-containing resin, and the desorbed solution was collected.

[0056] Water four times the theoretical hydrolysis amount was added to the desorbed solution for hydrolysis. Finally, the obtained germanium concentrate was analyzed for weight and composition. The germanium content was 47% and the germanium recovery rate was 95%.

Claims

1. A method for recovering high-quality germanium concentrate from scrapped glass optical fibers, characterized in that: Including the following processes: The scrapped glass optical fiber is crushed and sieved to obtain optical fiber powder; Mix the optical fiber powder and NaOH or Na2CO3 evenly, and the molar ratio of NaSi to NaGe in the mixture is 3-6:1; Calcine the mixture at 500-800°C for 2-4h; The roasted material is mixed with water at a solid-liquid ratio of 1:4-10, heated to 50-100°C, stirred, dissolved, and a leachate is produced; The leaching liquid is filtered, and the obtained filtered clear liquid is sent from the device inlet to a spray device filled with adsorption resin at a temperature of 5-40°C and a flow rate of 5-50 mm / min; At 50-80°C, at a flow rate of 10-100 mm / min, an inorganic acid desorbent is sent from the device outlet to the spray device to backwash the germanium-containing resin, and the desorbed liquid is collected; Add 3 to 5 times the theoretical hydrolysis amount of water to the desorbed liquid to obtain the target germanium concentrate.

2. The recycling method according to claim 1, characterized in that: The germanium mass content of the scrapped glass optical fiber is 0.05-0.4%, and the remainder is silicon dioxide.

3. The recycling method according to claim 1, characterized in that: The proportion of the optical fiber powder with a particle size of less than 200 meshes is greater than 90%.

4. The recycling method according to claim 1, characterized in that: The stirring speed is 100-800 r / min.

5. The recycling method according to claim 1, characterized in that: The dissolution time is 30 to 150 min.

6. The recycling method according to claim 1, characterized in that: The adsorption resin is IRA-985 resin, and the resin particle size is 1.5-4 mm.

7. The recycling method according to claim 1, characterized in that: The retention time of the filtered clear liquid in the spray device is 20 to 60 minutes.

8. The recycling method according to claim 1, characterized in that: The main component of the inorganic acid desorbent is hydrochloric acid, and the concentration of the hydrochloric acid is 3-10 mol / L.

9. The recycling method according to claim 1, characterized in that: The germanium mass content of the germanium concentrate is greater than 40%.

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