CN113881847B - Method for recovering silver from waste circuit board - Google Patents
Method for recovering silver from waste circuit board Download PDFInfo
- Publication number
- CN113881847B CN113881847B CN202010635203.3A CN202010635203A CN113881847B CN 113881847 B CN113881847 B CN 113881847B CN 202010635203 A CN202010635203 A CN 202010635203A CN 113881847 B CN113881847 B CN 113881847B
- Authority
- CN
- China
- Prior art keywords
- silver
- mixing
- liquid
- metal
- phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
- C22B7/007—Wet processes by acid leaching
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B11/00—Obtaining noble metals
- C22B11/04—Obtaining noble metals by wet processes
- C22B11/042—Recovery of noble metals from waste materials
- C22B11/046—Recovery of noble metals from waste materials from manufactured products, e.g. from printed circuit boards, from photographic films, paper or baths
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention provides a method for recovering silver from waste circuit boards. In the recovery method provided by the invention, the circuit board is firstly disassembled, crushed and the like to obtain metal-containing powder, then the metal-containing powder is mixed with nitric acid solution for immersion extraction to form silver-containing pickle liquor, then the obtained pickle liquor is mixed with specific emulsion for extraction, silver ions are converted into silver simple substances to be extracted from the pickle liquor, and then demulsification is carried out to separate the silver simple substances. The method provided by the invention can directly extract and recycle silver in the leaching solution containing multiple metals, does not need to set a separation process after wet treatment to obtain a single target metal solution and then carry out subsequent recycling operation, does not involve the problems of base metal recycling and the like, and compared with the prior art, the method has the advantages of greatly shortening and simplifying the process flow, improving the extraction efficiency and having lower cost.
Description
Technical Field
The invention relates to the field of resource circulation, in particular to a method for recovering silver from waste circuit boards.
Background
At present, the communication technology is rapidly developed, and the popularity of the mobile phone is very high for the national people. Because the mobile phone is updated quickly, the average service life of each mobile phone is about two years, and the yield of the waste mobile phones is increased. The circuit board is used as a core component in the mobile phone, has a small volume, wherein the noble metal gold content is about 0.86-1.6 kg/t, the silver content is about 0.14-5.8 kg/t, and the circuit board contains abundant metal types and noble metal content higher than that of original mineral products, has high recovery value, is also the component with the highest metal content and the largest recovery benefit in the waste mobile phone, and is known as a city mine. The mobile phone circuit board belongs to dangerous waste, contains various harmful metals such as As, hg, pb, cd, cr, and the like, has complex metal components, and can cause harm to ecological environment and human health when being improperly treated.
At present, the circuit board recovery research of large-scale electrical appliances such as computers is more, the targeted green high-efficiency recovery technology of the waste mobile phones is not mature, and recovery enterprises and factories often recover valuable metals in the mobile phones based on the traditional metallurgical mode.
Valuable metals in the waste mobile phone circuit boards are usually recovered by combining wet treatment with a separation recovery process. The wet method is to leach the metal from the circuit board into the solution by acid, alkali and other reagents, and the metal in the solution is usually recovered by substitution and electrolysis, and the two methods generally need to be used as recovery steps after separation processes of extraction-back extraction and adsorption resolution with high selectivity and are used in a single target metal solution after most of gold impurities are removed. The electrolytic method has higher requirements on the separation process after wet treatment, and because the metal components of the mobile phone circuit board are complex, the target metal solution with higher purity is difficult to obtain through the separation process, so that the purity of the recovered product is lower, the product needs to be purified again, a large amount of energy sources are consumed, and the cost is higher. The displacement method is generally required to be provided with a separation process before application, consumes more base metals, is easy to generate oxide or hydroxide on the metal surface in an alkaline environment to inhibit reaction, often has base metal impurities in products, often requires further purification, and increases working procedures, is complicated in flow and is high in cost due to the treatment of the base metals in waste liquid.
Therefore, the conventional recovery method generally has a series of problems of complex process flow, high cost consumption, low efficiency, large pollution, large cost for pollutant treatment, and the like, so that the market price of the waste mobile phone is nearly equivalent to the material value after disassembly, and along with the increasing of the scrapping amount of the mobile phone, the economic and environmental benefits of the recovery technology face a great challenge.
Disclosure of Invention
In view of the above, the present invention aims to provide a method for recovering silver from waste circuit boards. The recovery method provided by the invention can simplify the process flow, improve the recovery efficiency and reduce the recovery cost.
The invention provides a method for recovering silver from waste circuit boards, which comprises the following steps:
a) Disassembling, crushing and sorting the circuit board to obtain metal-containing powder;
b) Mixing and soaking the metal-containing powder with nitric acid solution, and then carrying out solid-liquid separation to obtain pickle liquor;
c) Mixing the pickle liquor with the emulsion, standing and separating the pickle liquor to obtain oil liquid after silver extraction;
d) Mixing the oil liquid after silver extraction with a demulsifier and carrying out solid-liquid separation to obtain silver solid powder;
in said step b), said emulsion comprises a membrane phase and an internal aqueous phase;
the membrane phase comprising a solute and a solvent; the solute comprises the following components in terms of volume concentration of each component in the membrane phase:
5% -25% of emulsifying agent;
0.25 to 0.5 percent of silver extracting carrier;
1% -5% of a film reinforcing agent;
the silver extracting carrier is one or more of Cyanex 302, cyanex471, petroleum sulfide and calixarene;
the inner water phase is an aqueous solution of a reducing agent.
Preferably, the emulsion is obtained by:
mixing and stirring the membrane phase and the internal water phase to form emulsion;
the stirring speed is 3000-5000 r/min, and the stirring time is 5-25 min.
Preferably, in the step c), the volume ratio of the emulsion to the pickling solution is 1:3-5.
Preferably, in the step c), the mixing is stirring mixing; the stirring speed is 300-450 r/min, and the stirring time is 5-15 min.
Preferably, in the step b):
the concentration of the nitric acid liquid is 4-6 mol/L;
the solid-liquid ratio of the metal-containing powder to the nitric acid liquid is 1g to (10-25) mL.
Preferably, in the step b):
the temperature of the mixed impregnation is 40-60 ℃ and the time is 1-3.5 h;
the mixing and soaking process is accompanied by stirring, and the rotating speed of the stirring is 300-500 r/min.
Preferably, the emulsifier is selected from Span 80, span 83 or Span 85;
the film reinforcing agent is liquid paraffin or polybutadiene;
the membrane solvent is kerosene or sulfonated kerosene.
Preferably, the reducing agent is vitamin C and/or hydroxylamine hydrochloride;
the volume concentration of the inner water phase is 1% -5%;
the volume ratio of the membrane phase to the internal water phase is 1:1-1.1.
Preferably, in the step d), the demulsifier is one or more selected from absolute ethyl alcohol, diethyl ether, acetone and petroleum ether.
Preferably, in the step d), the solid-liquid separation is centrifugal separation;
the rotational speed of the centrifugal separation is 6000-9000 r/min;
in the step d), after the solid-liquid separation, the method further comprises: washing and drying the obtained solid;
in the step a), the particle size of the metal-containing powder is 20 to 100 mesh.
The method comprises the steps of firstly carrying out treatments such as disassembly and crushing on a circuit board to obtain metal-containing powder, then mixing the metal-containing powder with nitric acid solution for soaking and extraction to form silver-containing pickle liquor, then mixing and extracting the obtained pickle liquor with specific emulsion, converting silver ions into silver simple substances, extracting the silver simple substances from the pickle liquor, and then carrying out demulsification to separate the silver simple substances. The method provided by the invention can directly extract and recycle silver in the leaching solution containing multiple metals, does not need to set a separation process after wet treatment to obtain a single target metal solution and then carry out subsequent recycling operation, does not involve the problems of base metal recycling and the like, and compared with the prior art, the method has the advantages of greatly shortening and simplifying the process flow, improving the extraction efficiency and having lower cost.
Test results show that the recovery method provided by the invention has the silver extraction rate of more than 95%.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of an emulsion extraction step of the present invention;
FIG. 2 is a process flow diagram of the recovery process of the present invention;
FIG. 3 is an SEM image of the product obtained in example 2;
FIG. 4 is an SEM image of the product obtained in example 3;
FIG. 5 is an SEM image of the product obtained in example 4.
Detailed Description
The invention provides a method for recovering silver from waste circuit boards, which comprises the following steps:
a) Disassembling, crushing and sorting the circuit board to obtain metal-containing powder;
b) Mixing and soaking the metal-containing powder with nitric acid solution, and then carrying out solid-liquid separation to obtain pickle liquor;
c) Mixing the pickle liquor with the emulsion, standing and separating the pickle liquor to obtain oil liquid after silver extraction;
d) Mixing the oil liquid after silver extraction with a demulsifier and carrying out solid-liquid separation to obtain silver solid powder;
in said step b), said emulsion comprises a membrane phase and an internal aqueous phase;
the membrane phase comprising a solute and a solvent; the solute comprises the following components in terms of volume concentration of each component in the membrane phase:
5% -25% of emulsifying agent;
0.25 to 0.5 percent of silver extracting carrier;
1% -5% of a film reinforcing agent;
the silver extracting carrier is one or more of Cyanex 302, cyanex471, petroleum sulfide and calixarene;
the inner water phase is an aqueous solution of a reducing agent.
The method comprises the steps of firstly carrying out treatments such as disassembly and crushing on a circuit board to obtain metal-containing powder, then mixing the metal-containing powder with nitric acid solution for soaking and extraction to form silver-containing pickle liquor, then mixing and extracting the obtained pickle liquor with specific emulsion, converting silver ions into silver simple substances, extracting the silver simple substances from the pickle liquor, and then carrying out demulsification to separate the silver simple substances. The method provided by the invention can directly extract and recycle silver in the leaching solution containing multiple metals, does not need to set a separation process after wet treatment to obtain a single target metal solution and then carry out subsequent recycling operation, does not involve the problems of base metal recycling and the like, and compared with the prior art, the method has the advantages of greatly shortening and simplifying the process flow, improving the extraction efficiency and the product purity and having lower cost.
Regarding step a):
in the invention, the circuit board is preferably a circuit board of a waste mobile phone, namely, the recovery method is a method for recovering silver from the circuit board of the waste mobile phone. In the present invention, the manner of the disassembling, crushing and sorting is not particularly limited, and is a conventional pretreatment operation manner in the art. In the present invention, grinding and drying are preferably further included after the sorting. The nonmetallic substances are initially separated by the pretreatment of the above-mentioned columns to obtain a metalliferous powder, the particle size of the metalliferous powder preferably being 20-100 mesh.
Regarding step b):
the concentration of the nitric acid liquid is preferably 4-6 mol/L. The solid-liquid ratio of the metal-containing powder to the nitric acid liquid is preferably 1g to (10-25) mL. In the above mixed impregnation process, silver in the metal-containing powder reacts with an acid as shown in the following formula (1). The temperature of the mixed impregnation is preferably 40-60 ℃, and the time of the mixed impregnation is preferably 1-3.5 h. The mixing and soaking are preferably carried out under the condition of constant-temperature magnetic stirring, and the rotating speed of stirring is preferably 300-500 r/min. After mixing and soaking, solid-liquid separation is carried out. The mode of the solid-liquid separation is not particularly limited in the present invention, and conventional separation operations well known to those skilled in the art, such as filtration and the like, may be used. After solid-liquid separation, the pickle liquor is obtained, wherein silver exists in the form of silver nitrate which can be completely ionized, and the extraction of silver by the subsequent emulsion membrane method is facilitated.
3Ag+4HNO 3 →3AgNO 2 +NO 2 ↑+H 2 O formula (1).
Regarding step c):
the emulsion includes a membrane phase and an internal aqueous phase. The membrane phase comprising a solute and a solvent; wherein, the volume ratio of the solute to the solvent is preferably 70-90%. For a solute, the solute comprises the following components in terms of volume concentrations of the components in the membrane phase:
5% -25% of emulsifying agent;
0.25 to 0.5 percent of silver extracting carrier;
1 to 5 percent of film reinforcing agent.
Among them, the emulsifier is preferably Span 80 (sorbitan monooleate), span 83 (sorbitan sesquioleate) or Span 85 (sorbitan trioleate). The volume concentration of the emulsifier in the film phase is 5% -25%; in some embodiments of the invention, the volume concentration is 5%, 6% or 25%.
The silver extracting carrier is one or more of Cyanex 302 (diisooctyl thiophosphinic acid), cyanex471, petroleum sulfide and calixarene; cyanex 302 is preferred. The volume concentration of the silver extracting carrier in the film phase is 0.25% -0.5%; in some embodiments of the invention, the volume concentration is 0.4%.
The film enhancer is preferably liquid paraffin or polybutadiene; more preferably liquid paraffin. The volume concentration of the film reinforcing agent in the film phase is 1% -5%; in some embodiments of the invention, the volume concentration is 3% or 5%.
The solvent in the membrane phase is preferably kerosene or sulfonated kerosene; more preferably kerosene.
The inner water phase is an aqueous solution of a reducing agent. Wherein the reducing agent is preferably vitamin C and/or hydroxylamine hydrochloride; more preferably vitamin C. The volume concentration of the inner water phase is preferably 1% -5%; in some embodiments of the invention, the volume concentration is 5%.
In the present invention, the volume ratio of the membrane phase to the internal aqueous phase is preferably 1:1 (1 to 1.1), more preferably 1:1.
In the present invention, the emulsion is preferably obtained by: and mixing and stirring the membrane phase and the internal water phase to form emulsion. Wherein the rotation speed of stirring is preferably 3000-5000 r/min; under the condition of the rotating speed, emulsion with good stability can be obtained, if the rotating speed is too low or too high, the emulsion is unstable, and swelling or cracking occurs during subsequent extraction to influence silver extraction; in some embodiments of the invention, the rotational speed is 3500r/min. The stirring time is preferably 5-25 min; in some embodiments of the invention, the stirring time is 10 minutes. And mixing and stirring the materials to obtain emulsion.
In the invention, the pickle liquor is taken as an external water phase, and when the pickle liquor is mixed with the emulsion, the volume ratio of the emulsion to the pickle liquor is preferably 1:3-5; under the above proportion, the extraction rate of silver is improved, and if the proportion is too low or too high, the subsequent extraction rate of silver and the swelling rate of the emulsion after extraction are adversely affected. In some embodiments of the invention, the volume ratio is 1:3.
In the present invention, the mixing is preferably stirring mixing; the stirring speed is preferably 300-450 r/min, and the emulsion is uniformly dispersed in the pickle liquor in the form of small liquid drops under the slow stirring to extract silver; the specific extraction process is as follows: the silver ions in the pickle liquor are complexed with the silver extraction carrier in the membrane phase and then transported to the inner water phase through the membrane phase, the silver ions are reduced into silver metal simple substances with certain shape and size under the action of the inner water phase reducing agent, and the silver extraction carrier returns to continuously transport the silver ions in the outer water phase (namely the pickle liquor) to the inner water phase. The extraction process is shown in fig. 1, and fig. 1 is a schematic diagram of the emulsion extraction step of the present invention. Wherein Ag is + Silver ions in the inner water phase and the outer water phase; HL is a silver extraction carrier in the film phase; agL (HL) m-1 Is a complex formed by silver and a carrier in a film phase, and m is coordination number of silver and a silver extracting carrier; h + Is hydrogen ion in inner and outer water phases. Taking the reducing agent vitamin C as an example, the reaction shown in the formula (2) occurs in the emulsion extraction process.
2Ag + +C 6 H 8 O 6 →2Ag↓+C 6 H 6 O 6 +2H + Formula (2).
The invention preferably controls the rotating speed to 300-450 r/min, which is favorable for obtaining high extraction rate, if the rotating speed is too low, the emulsion cannot be dispersed in the external water phase, the extraction rate is seriously affected, and if the rotating speed is too high, emulsion liquid drops are broken, and the extraction rate is reduced. In some embodiments of the invention, the extraction rate is 300r/min. In the present invention, the stirring time is preferably 5 to 15min, and in some embodiments of the present invention, the stirring time is 5min. Through the mixed extraction, silver ions in the outer water phase are continuously converted into silver simple substances in the inner water phase.
After the above-mentioned mixing, standing and separating. And gradually layering an aqueous phase and an oil phase containing silver simple substances in the standing process, wherein the standing time is not particularly limited until the phases are completely layered. And after the oil phase and the water phase are layered, carrying out liquid separation operation to obtain the oil liquid containing the silver simple substance. The present invention is not particularly limited to the above-described liquid separation operation, and may be a conventional liquid separation operation well known to those skilled in the art.
Regarding step d):
in the invention, the demulsifier is preferably one or more of absolute ethyl alcohol, diethyl ether, acetone and petroleum ether; the demulsifier has the function of a cleaning agent and comprises the following specific operations: mixing the demulsifier with the oil liquid obtained in the step c) after silver extraction, performing centrifugal separation, and performing solid-liquid separation on turbid liquid after emulsion rupture under the centrifugal action. The rotation speed of the centrifugal separation is preferably 6000-9000 r/min. After the demulsification and the solid-liquid separation, the method preferably further comprises the following steps: the solid product is washed with a cleaning agent. Specifically, after the centrifugal separation, maintaining the centrifugal operation, and continuously adding cleaning agent for multiple times to wash until no organic matter remains; the type of the cleaning agent is the same as that of the demulsifier, and is not described in detail herein. The dosage of the demulsifier is not particularly limited during demulsification, and the demulsifier can be added according to the conventional dosage used in the conventional demulsification operation in the field; after demulsification, the dosage of the cleaning agent is not particularly limited in the subsequent washing process, and the material can be sufficiently cleaned. In the present invention, the above washing is preferably further carried out by drying, and the silver solid powder is obtained after drying.
The process of the recovery method provided by the invention is shown in fig. 2, and fig. 2 is a process flow chart of the recovery method.
The recovery method provided by the invention has the following beneficial effects:
1. the method can directly extract and recover silver from the leaching solution containing various metals, does not need to set a separation process after wet treatment to obtain a single target metal solution and then carry out subsequent recovery operation, does not relate to the problems of base metal recovery and the like, can realize one-step separation and recovery of noble metal silver in the leaching solution, and greatly shortens and simplifies the process flow compared with the prior art.
2. The method can improve the extraction efficiency of silver and the purity of the product. The proportion of the silver extraction carrier, the emulsification rotating speed in the emulsion preparation, the mixing proportion of the emulsion and the pickle liquor and the extraction rotating speed are particularly critical, and the higher extraction rate can be ensured under the limit of the invention on the four factors.
3. The cost of the reagent used in the recovery process is lower, which is beneficial to reducing the cost of the whole recovery method.
4. According to the recovery method, the emulsifiers with different types and amounts are used in the emulsion preparation in the previous step, so that silver solid products with different shapes and sizes can be obtained after demulsification, and therefore, the shape of the silver solid simple substance can be regulated and controlled by adjusting the emulsifier reagent, and the value of recovering the obtained secondary metal is improved.
For a further understanding of the present invention, preferred embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are merely intended to illustrate further features and advantages of the invention, and are not limiting of the claims of the invention.
Example 1
1.1 recovery treatment
S1, disassembling, crushing, sorting, grinding and drying the waste mobile phone circuit board to obtain 100-mesh metal-containing powder.
S2, mixing metal-containing powder with nitric acid solution (the concentration is 5.5M) according to the solid-to-liquid ratio of 1g to 10mL, and carrying out dipping reaction in a constant-temperature magnetic stirring water bath kettle, wherein the temperature is controlled to be 60 ℃, the magnetic stirring speed is 350r/min, and the reaction time is 3.5h. And then filtering to obtain pickle liquor.
S3, film phase: span 80 emulsifier 5%, silver extracting carrier Cyanex 302.4%, liquid paraffin 3% and kerosene as solvent. Inner aqueous phase: the concentration of the vitamin C in the aqueous solution is 5%.
Mixing the membrane phase and the internal water phase according to the volume ratio of 1:1, and emulsifying for 10min at the stirring speed of 3500r/min to obtain emulsion.
Mixing the emulsion and the pickling solution according to the volume ratio of 1:3, and extracting for 5min at the stirring speed of 300r/min. And then standing and separating to obtain the oil liquid after silver extraction.
S4, placing the obtained silver-extracted oil liquid into a 50mL centrifuge tube, adding absolute ethyl alcohol and petroleum ether, performing demulsification and cleaning on a solid product in a 9000r/min high-speed centrifugal mode, and drying to obtain silver solid powder.
1.2 test
The extraction rate is calculated as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,
C 0 - -the silver ion content in the pickle liquor obtained in the step S2, mg/L;
C 1 - -content of silver ions remaining in the aqueous phase solution after separation in step S3, mg/L.
The test results are shown in Table 1.
Example 2
1.1 recovery treatment
S1, disassembling, crushing, sorting, grinding and drying the waste mobile phone circuit board to obtain 100-mesh metal-containing powder.
S2, mixing metal-containing powder with nitric acid solution (the concentration is 5.5M) according to the solid-to-liquid ratio of 1g to 10mL, and carrying out dipping reaction in a constant-temperature magnetic stirring water bath kettle, wherein the temperature is controlled to be 60 ℃, the magnetic stirring speed is 350r/min, and the reaction time is 3.5h. And then filtering to obtain pickle liquor.
S3, film phase: span 80 emulsifier 10%, silver extracting carrier Cyanex 302.4%, liquid paraffin 3% and kerosene as solvent. Inner aqueous phase: the concentration of the vitamin C in the aqueous solution is 5%.
Mixing the membrane phase and the internal water phase according to the volume ratio of 1:1, and emulsifying for 10min at the stirring speed of 3500r/min to obtain emulsion.
Mixing the emulsion and the pickling solution according to the volume ratio of 1:3, and extracting for 5min at the stirring speed of 300r/min. And then standing and separating to obtain the oil liquid after silver extraction.
S4, placing the obtained silver-extracted oil liquid into a 50mL centrifuge tube, adding absolute ethyl alcohol and petroleum ether, performing demulsification and cleaning on a solid product in a 9000r/min high-speed centrifugal mode, and drying to obtain silver solid powder.
1.2 characterization and testing
(1) Extraction rate
The extraction yield of silver was tested according to the test method of example 1, the results are shown in table 1.
(2) SEM characterization
The solid product obtained was subjected to scanning electron microscope characterization, the results of which are shown in fig. 3, and fig. 3 is an SEM image of the product obtained in example 2. It can be seen that the silver solid product obtained is nanosheet-shaped.
Example 3
1.1 recovery treatment
S1, disassembling, crushing, sorting, grinding and drying the waste mobile phone circuit board to obtain 100-mesh metal-containing powder.
S2, mixing metal-containing powder with nitric acid solution (the concentration is 5.5M) according to the solid-to-liquid ratio of 1g to 10mL, and carrying out dipping reaction in a constant-temperature magnetic stirring water bath kettle, wherein the temperature is controlled to be 60 ℃, the magnetic stirring speed is 350r/min, and the reaction time is 3.5h. And then filtering to obtain pickle liquor.
S3, film phase: 15% of Span 80 emulsifier, 0.4% of silver extracting carrier Cyanex 302, 3% of liquid paraffin and kerosene as solvent. Inner aqueous phase: the concentration of the vitamin C in the aqueous solution is 5%.
Mixing the membrane phase and the internal water phase according to the volume ratio of 1:1, and emulsifying for 10min at the stirring speed of 3500r/min to obtain emulsion.
Mixing the emulsion and the pickling solution according to the volume ratio of 1:3, and extracting for 5min at the stirring speed of 300r/min. And then standing and separating to obtain the oil liquid after silver extraction.
S4, placing the obtained silver-extracted oil liquid into a 50mL centrifuge tube, adding absolute ethyl alcohol and petroleum ether, performing demulsification and cleaning on a solid product in a 9000r/min high-speed centrifugal mode, and drying to obtain silver solid powder.
1.2 characterization and testing
(1) Extraction rate
The extraction yield of silver was tested according to the test method of example 1, the results are shown in table 1.
(2) SEM characterization
The solid product obtained was subjected to scanning electron microscope characterization, the results of which are shown in fig. 4, and fig. 4 is an SEM image of the product obtained in example 3. It can be seen that the silver solid product obtained is nanoparticulate.
Example 4
1.1 recovery treatment
S1, disassembling, crushing, sorting, grinding and drying the waste mobile phone circuit board to obtain 100-mesh metal-containing powder.
S2, mixing metal-containing powder with nitric acid solution (the concentration is 5.5M) according to the solid-to-liquid ratio of 1g to 10mL, and carrying out dipping reaction in a constant-temperature magnetic stirring water bath kettle, wherein the temperature is controlled to be 60 ℃, the magnetic stirring speed is 350r/min, and the reaction time is 3.5h. And then filtering to obtain pickle liquor.
S3, film phase: span 80 emulsifier 20%, silver extracting carrier Cyanex 302.4%, liquid paraffin 3% and kerosene as solvent. Inner aqueous phase: the concentration of the vitamin C in the aqueous solution is 5%.
Mixing the membrane phase and the internal water phase according to the volume ratio of 1:1, and emulsifying for 10min at the stirring speed of 3500r/min to obtain emulsion.
Mixing the emulsion and the pickling solution according to the volume ratio of 1:3, and extracting for 5min at the stirring speed of 300r/min. And then standing and separating to obtain the oil liquid after silver extraction.
S4, placing the obtained silver-extracted oil liquid into a 50mL centrifuge tube, adding absolute ethyl alcohol and petroleum ether, performing demulsification and cleaning on a solid product in a 9000r/min high-speed centrifugal mode, and drying to obtain silver solid powder.
1.2 characterization and testing
(1) Extraction rate
The extraction yield of silver was tested according to the test method of example 1, the results are shown in table 1.
(2) SEM characterization
The solid product obtained was subjected to scanning electron microscope characterization, and the results are shown in fig. 5, and fig. 5 is an SEM image of the product obtained in example 4. It can be seen that the silver solid product obtained is in the form of micron-sized particles.
Examples 5 to 12
The procedure of example 1 was followed, except that the type and amount of the emulsifier were adjusted. After extraction of recovered silver, the test was performed according to the test and characterization methods of example 2.
See table 1 for the raw materials, operating conditions and test results for each example.
TABLE 1 preparation conditions and test results for examples 1 to 12
In table 1, the usage ratio of the film enhancer, the emulsifier and the carrier refers to the volume percentage concentration of the corresponding components in the whole film phase solution; the dosage ratio of the membrane solvent refers to the volume percent concentration of the membrane solvent in the integral membrane phase solution; the emulsion-to-water ratio refers to the volume ratio of the membrane phase to the internal aqueous phase when preparing the emulsion.
As can be seen from the above embodiments, the method provided by the present invention can obtain high extraction efficiency; in addition, silver solid products with different morphologies can be obtained by adjusting the emulsifier, so that the recovery value of the silver solid products is improved.
The above description of the embodiments is only for aiding in the understanding of the method of the present invention and its core ideas. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (4)
1. The method for recovering silver from the waste circuit board is characterized by comprising the following steps of:
a) Disassembling, crushing and sorting the circuit board to obtain metal-containing powder;
b) Mixing and soaking the metal-containing powder with nitric acid solution, and then carrying out solid-liquid separation to obtain pickle liquor;
c) Mixing the pickle liquor with the emulsion, standing and separating the pickle liquor to obtain oil liquid after silver extraction;
d) Mixing the oil liquid after silver extraction with a demulsifier and carrying out solid-liquid separation to obtain silver solid powder;
in said step b), said emulsion comprises a membrane phase and an internal aqueous phase;
the membrane phase comprising a solute and a solvent; the solute comprises the following components in terms of volume concentration of each component in the membrane phase:
5% -25% of emulsifying agent;
0.25 to 0.5 percent of silver extracting carrier;
1% -5% of a film reinforcing agent;
the silver extracting carrier is Cyanex 302;
the emulsifier is selected from Span 83 or Span 85;
the inner water phase is an aqueous solution of a reducing agent;
the emulsion is obtained by:
mixing and stirring the membrane phase and the internal water phase to form emulsion;
the stirring speed is 3000-5000 r/min, and the stirring time is 5-25 min;
in the step c), the mixing is stirring mixing; the stirring speed is 300-450 r/min, and the stirring time is 5-15 min;
in the step d), the demulsifier is one or more selected from absolute ethyl alcohol, diethyl ether, acetone and petroleum ether;
in the step c), the volume ratio of the emulsion to the pickling liquid is 1:3-5;
in the step b):
the concentration of the nitric acid liquid is 4-6 mol/L;
the solid-liquid ratio of the metal-containing powder to the nitric acid liquid is 1g to (10-25) mL;
the temperature of the mixed impregnation is 40-60 ℃ and the time is 1-3.5 h;
the mixing and soaking process is accompanied by stirring, and the rotating speed of the stirring is 300-500 r/min.
2. The method of claim 1, wherein the film enhancer is liquid paraffin or polybutadiene;
the membrane solvent is kerosene or sulfonated kerosene.
3. The method of claim 1, wherein the reducing agent is vitamin C and/or hydroxylamine hydrochloride;
the volume concentration of the inner water phase is 1% -5%;
the volume ratio of the membrane phase to the internal water phase is 1:1-1.1.
4. The method according to claim 1, wherein in step d), the solid-liquid separation is a centrifugal separation;
the rotational speed of the centrifugal separation is 6000-9000 r/min;
in the step d), after the solid-liquid separation, the method further comprises: washing and drying the obtained solid;
in the step a), the particle size of the metal-containing powder is 20 to 100 mesh.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010635203.3A CN113881847B (en) | 2020-07-03 | 2020-07-03 | Method for recovering silver from waste circuit board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010635203.3A CN113881847B (en) | 2020-07-03 | 2020-07-03 | Method for recovering silver from waste circuit board |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113881847A CN113881847A (en) | 2022-01-04 |
| CN113881847B true CN113881847B (en) | 2023-04-28 |
Family
ID=79013236
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010635203.3A Active CN113881847B (en) | 2020-07-03 | 2020-07-03 | Method for recovering silver from waste circuit board |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113881847B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115029554A (en) * | 2022-02-17 | 2022-09-09 | 昆明理工大学 | Method for recovering silver from waste circuit board solder |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5885535A (en) * | 1997-05-27 | 1999-03-23 | Sumitomo Metal Mining Company, Limited | Process for extracting and recovering silver |
| CN101469371A (en) * | 2007-12-26 | 2009-07-01 | 王洪波 | Method for recycling noble metal in industrial wastewater or mineral smelting leaching liquor by supported liquid membrane technology |
| CN101550486B (en) * | 2009-05-07 | 2010-09-29 | 西安理工大学 | Method for separating and recovering gold or silver by inner-coupling liquid membrane |
| WO2011037820A1 (en) * | 2009-09-25 | 2011-03-31 | Dow Global Technologies Llc. | Olefin selective membrane comprising an ionic liquid and a complexing agent |
| CN103626254B (en) * | 2013-11-07 | 2015-10-21 | 西安建筑科技大学 | Liquid membrane emulsion technology is utilized to remove the method for prussiate in cyanide wastewater |
| CN110791649A (en) * | 2018-08-01 | 2020-02-14 | 南开大学 | Method for preparing nano material from metal in electronic waste |
| CN110484748B (en) * | 2019-09-06 | 2020-09-11 | 中南大学 | Method for selectively recovering silver from waste circuit board |
-
2020
- 2020-07-03 CN CN202010635203.3A patent/CN113881847B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN113881847A (en) | 2022-01-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Calgaro et al. | Fast copper extraction from printed circuit boards using supercritical carbon dioxide | |
| Zhou et al. | Recovery of gold from waste mobile phone circuit boards and synthesis of nanomaterials using emulsion liquid membrane | |
| WO2022213678A1 (en) | Method for recycling aluminum in waste positive electrode sheet by using selective leaching and application thereof | |
| CN105087935B (en) | The method of copper, indium and gallium is separately recovered in a kind of gallium waste target from copper and indium | |
| CN107400780A (en) | A kind of method that gold, silver and bronze are extracted in the plate from cell phone lines | |
| CN109554549A (en) | The method that high temperature and pressure leaches rare earth in recycling neodymium iron boron waste material | |
| CN105420502A (en) | Method for recovering indium from waste liquid crystal display screen panel | |
| CN105170108A (en) | Rice husk cellulose adsorbent, and preparation method and application thereof | |
| Cheng et al. | Extraction of cobalt (ii) by methyltrioctylammonium chloride in nickel (ii)-containing chloride solution from spent lithium ion batteries | |
| CN106086417A (en) | A kind of method extracting copper and gold from waste mobile phone circuit board | |
| CN113881847B (en) | Method for recovering silver from waste circuit board | |
| CN107720715A (en) | A kind of method for preparing battery ferric phosphate using phosphatization slag for raw material | |
| Li et al. | Ultrasonically assisted acid extraction of manganese from slag | |
| Zhu et al. | Emulsion liquid membrane for simultaneous extraction and separation of copper from nickel in ammoniacal solutions | |
| CN106861685B (en) | A kind of Ag/Ag2O/TiO2The preparation method of/diatomite composite photocatalytic material | |
| CN105907964B (en) | The separation method of vanadium, scandium, iron in a kind of acid solution | |
| CN108866337B (en) | A method of processing metal sludge | |
| CN105671324A (en) | Method for preparing ammonium rhenate from rhenium-enriched slags | |
| LIU et al. | Optimization of separation processing of copper and iron of dump bioleaching solution by Lix 984N in Dexing Copper Mine | |
| CN108070718B (en) | A kind of method of molybdenum in double-aqueous phase system extraction and separation aqueous solution | |
| Shi et al. | Separation and recovery of nickel and copper from multi-metal electroplating sludge by co-extracting and selective stripping | |
| CN111777082B (en) | Method for recovering sodium sulfate from raffinate of waste battery recovery liquid | |
| CN113699374A (en) | Method for enriching tin in low-concentration mixed tungsten ore containing tin | |
| Guocai et al. | Recovering indium with sulfating roasting from copper-smelting ash | |
| CN114182109A (en) | Nickel-cobalt feed liquid extraction impurity removal process and device thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |