CN112481499A - Method for recycling and reusing silver graphite waste - Google Patents
Method for recycling and reusing silver graphite waste Download PDFInfo
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- CN112481499A CN112481499A CN202011204322.XA CN202011204322A CN112481499A CN 112481499 A CN112481499 A CN 112481499A CN 202011204322 A CN202011204322 A CN 202011204322A CN 112481499 A CN112481499 A CN 112481499A
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- 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
- C22B7/005—Separation by a physical processing technique only, e.g. by mechanical breaking
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
- B07B7/00—Selective separation of solid materials carried by, or dispersed in, gas currents
- B07B7/08—Selective separation of solid materials carried by, or dispersed in, gas currents using centrifugal force
- B07B7/083—Selective separation of solid materials carried by, or dispersed in, gas currents using centrifugal force generated by rotating vanes, discs, drums, or brushes
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/205—Preparation
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- 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
- C22B11/02—Obtaining noble metals by dry processes
- C22B11/021—Recovery of noble metals from waste materials
- C22B11/025—Recovery of noble metals from waste materials from manufactured products, e.g. from printed circuit boards, from photographic films, paper, or baths
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- 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
- C22B7/001—Dry processes
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- 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 discloses a method for recovering and reusing silver graphite waste, which comprises the following steps: the silver graphite waste is prepared into silver graphite powder, silver powder and silver ingots through the steps of smelting, crushing, separating, casting, sieving and the like, and the silver graphite powder, the silver powder and the silver ingots are respectively put into various products for use. The method has the advantages that the silver graphite waste material is recycled, the decarburization process is avoided, the emission of carbon dioxide gas is reduced, the environmental protection is facilitated, the graphite powder and the silver are recycled, and the recycling and production cost is reduced.
Description
Technical Field
The invention belongs to the field of precious metal recovery, and particularly relates to a method for recovering and recycling silver graphite waste.
Background
The silver-graphite electrical contact material has excellent fusion welding resistance and lower resistivity, is widely applied to low-voltage electrical appliances, is produced by adopting a powder metallurgy process, and can inevitably generate leftover materials and waste products in the production process. For silver graphite waste, the decarbonization process is usually adopted in the electrical alloy industry to recover silver, and silver graphite powdery waste generated by cutting in the production process is directly decarbonized in an air furnace at the temperature of 500-800 ℃ under the action of high temperature and oxygen to obtain silver scraps. For the waste products in the shape of extruded rod and extruded cylindrical cake, expansion and cracking of the alloy block are carried out in a high-temperature furnace with the atmosphere protection of over 960 ℃, and then decarburization is carried out in an air furnace with the temperature of 500-800 ℃ under the action of high temperature and oxygen to obtain the silver scrap.
The disadvantages of the above scheme are that the decarburization production process of graphite under the action of high temperature and oxygen takes a long time; secondly, the decarburization process is that graphite and oxygen react to generate carbon dioxide which is a greenhouse gas and is discharged in large quantity, thus being not beneficial to environmental protection; thirdly, the decarburized silver powder cannot be reused as silver powder after long-time high-temperature sintering.
Therefore, it is necessary to develop a new silver-graphite waste recycling process, which avoids the decarburization process, reduces the emission of carbon dioxide gas, recycles graphite powder and silver, and reduces the recycling and production costs.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for recycling silver graphite waste, which avoids a decarburization process, reduces the emission of carbon dioxide gas and recycles silver powder and graphite powder.
In order to realize the first purpose, the silver graphite waste recovery method comprises the following steps:
s1, crushing: putting the silver graphite waste into a crucible for heating and smelting, and stirring to break the silver graphite waste into silver graphite powder I and molten silver liquid;
s2, separation: firstly, taking out the silver graphite powder I floating on the silver liquid, then casting the silver liquid into a silver ingot I, and cooling the taken out silver graphite powder I to room temperature;
s3, screening silver graphite powder: setting the frequency A of a grading wheel of the jet mill and the pressure a of compressed air, and sieving the cooled silver graphite powder I in the jet mill to obtain silver graphite powder II; the frequency A of the grading wheel is 100-150Hz, and the pressure a of the compressed air is 0.1-0.2 MPa;
s4, screening silver powder: setting the frequency B of a grading wheel of the jet mill and the pressure B of compressed air, and continuously sieving by the jet mill to obtain silver powder I, wherein the frequency B of the grading wheel is 10-25Hz, and the pressure B of the compressed air is 0.6-0.7 MPa;
s5, recovering silver scraps: and taking out the silver scraps which cannot be sieved in the jet mill equipment, putting the silver scraps into a crucible, and smelting and casting the silver scraps into silver ingots II.
The silver graphite waste is further set to be one or a mixture of powder, silk, rod and cylindrical cake.
The smelting temperature in the step S1 is further set to be 960-1400 ℃.
In addition, the invention also provides a recycling method of the recycled material obtained based on the recycling method, after the silver content of the silver graphite powder II is detected, the silver graphite powder II is mixed with silver powder and graphite powder according to a proportion formula, and the mixture is fed to produce a silver graphite product; feeding qualified silver powder I as a silver layer of an electrical contact multilayer product; and putting the qualified silver ingots I and II as pure silver ingot raw materials into the production of the silver-based electrical contact product.
The innovative mechanism of the invention is as follows: putting the silver graphite waste into a smelting furnace, raising the temperature of the waste to 960-1400 ℃ by induction heating, melting the silver in the silver graphite waste, converging the silver liquid at the bottom of a crucible under the action of self gravity and stirring, crushing the silver graphite massive scraps after partial silver is lost into powder, and floating the silver graphite powder I on the silver liquid under the action of density difference. And casting the silver liquid into a silver ingot I, and cooling the silver graphite powder I to room temperature.
The melting point of the graphite powder is above 3000 ℃, the particle size can not be changed basically, and the particles become small after partial graphite powder is contacted with air and oxidized, so that the graphite powder can be recycled.
The silver graphite powder I floating on the silver liquid is formed by mixing silver powder and graphite powder, the silver powder is blocked by the graphite powder to melt and flow, and cannot be gathered into the silver liquid, so that the silver powder is mixed in the graphite powder after the silver graphite powder I is cooled, but the particle size and the morphology of the silver powder subjected to high-temperature influence are not suitable for directly producing silver graphite products. Therefore, after the silver graphite powder II and the silver powder I which meet the product requirements are respectively obtained after the airflow milling, sieving and sorting, and the rest silver scraps which cannot be sieved are smelted into pure silver ingots II.
After the silver content of the silver graphite powder II obtained by the jet milling separation is detected, the silver graphite powder II is mixed with silver powder and graphite powder according to a proportion formula, the silver graphite product is produced by feeding, the metallographic phase of the product is shown in figure 2, the metallographic phase of the product is shown in figure 3, which is a metallographic phase diagram of the silver graphite product produced by the fresh graphite powder which is not produced by feeding, the metallographic structures of the silver graphite product and the fresh graphite powder are equivalent, and the metallographic structures of the silver graphite product and the fresh.
The silver powder I obtained by the jet mill separation is used for producing the silver layer of the electric contact composite product, the silver powder impurity detection result is shown in table 1, the metallographic phase is shown in figure 4, the comparison figure 5 is a silver layer metallographic phase diagram of the electric contact composite product produced by the new silver powder which is not fed and produced, the metallographic structures of the silver layer and the metallographic phase diagram are equivalent, and the silver layer and the metallographic phase diagram are qualified.
TABLE 1 silver powder chemical composition detection
The detection results of the silver ingot I and the silver ingot II are respectively shown in the table 2 and the table 3, and the national standard detection result of the silver ingot is met, so that the silver ingot can be used as a pure silver ingot raw material to be put into production of silver-based electrical contact products.
TABLE 2 silver ingot chemical composition detection
TABLE 3 silver ingot chemical composition detection
Compared with the prior art, the invention has the advantages and positive effects that: 1. the silver graphite waste is recycled, so that a decarburization process is avoided, the emission of carbon dioxide gas is reduced, and the environment protection is facilitated; 2. the graphite powder and the silver are recycled, and the recycling and production cost is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.
FIG. 1 is a process scheme;
FIG. 2 is a gold phase diagram of a silver graphite product produced from silver graphite powder II;
FIG. 3 is a gold phase diagram of a silver graphite product produced from a new graphite powder;
FIG. 4 is a diagram of the gold phase of the silver layer of the electrical contact multilayer product produced from silver powder I;
FIG. 5 is a silver layer gold phase diagram of an electrical contact multilayer product produced from silver powder recovered by the process of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.
Example one
(1) Putting the silver graphite waste into an induction smelting furnace for heating, observing that silver is molten, and stirring to break the silver graphite waste into silver graphite powder;
(2) stopping stirring, stopping heating, and taking the silver graphite powder I out of the smelting furnace for cooling;
(3) casting the silver liquid in the smelting furnace into a silver ingot, taking a sample after mold stripping and water cooling, detecting impurities according to the national standard of the silver ingot, and detecting the content of C%, wherein the C% is not higher than 0.0030%;
(4) cooling the silver graphite powder to room temperature, putting the silver graphite powder into an air current mill for sieving, setting the frequency of a grading wheel to be 100Hz and the pressure of compressed air to be 0.1MPa to obtain the silver graphite powder, sampling and detecting the silver graphite powder in the air current mill equipment after the equipment is sieved for a period of time, and stopping sieving when the content of graphite is lower than 0.0030 percent;
(5) changing a charging barrel, setting the frequency of a grading wheel to be 15Hz and the pressure of compressed air to be 0.6MPa, continuously sieving in jet mill equipment to obtain silver powder, sampling, detecting impurities according to the national standard of silver ingots, and measuring the content of C%, wherein the C% is not higher than 0.0030%;
(6) taking out the silver leftover material which cannot be sieved out, putting the silver leftover material into a smelting furnace, casting into a silver ingot, taking out a sample after mold stripping and water cooling, detecting impurities according to the national standard of the silver ingot, and measuring the content of C%, wherein the C% is not higher than 0.0030%;
(7) silver graphite powder, silver powder and graphite powder are mixed according to a formula after the silver content is detected, and a silver graphite product is produced by feeding; feeding qualified silver powder to serve as a silver layer of an electrical contact multilayer product; and (3) taking the qualified silver ingots I and II as raw materials of pure silver ingots to be put into production of silver-based electrical contact products.
Example two
(1) Putting the silver graphite waste into an induction smelting furnace for heating, observing that silver is molten, and stirring to break the silver graphite waste into silver graphite powder;
(2) stopping stirring, stopping heating, and taking the silver graphite powder I out of the smelting furnace for cooling;
(3) casting the silver liquid in the smelting furnace into a silver ingot, taking a sample after mold stripping and water cooling, detecting impurities according to the national standard of the silver ingot, and detecting the content of C%, wherein the C% is not higher than 0.0030%;
(4) cooling the silver graphite powder to room temperature, putting the silver graphite powder into an air current mill for sieving, setting the frequency of a grading wheel to be 120Hz and the pressure of compressed air to be 0.2MPa to obtain the silver graphite powder, sampling and detecting the silver graphite powder in the air current mill equipment after the equipment is sieved for a period of time, and stopping sieving when the content of graphite is lower than 0.0030 percent;
(5) changing a charging barrel, setting the frequency of a grading wheel to be 20Hz and the pressure of compressed air to be 0.7MPa, continuously sieving in jet mill equipment to obtain silver powder, sampling, detecting impurities according to the national standard of silver ingots, and measuring the content of C%, wherein the C% is not higher than 0.0030%;
(6) taking out the silver leftover material which cannot be sieved out, putting the silver leftover material into a smelting furnace, casting into a silver ingot, taking out a sample after mold stripping and water cooling, detecting impurities according to the national standard of the silver ingot, and measuring the content of C%, wherein the C% is not higher than 0.0030%;
(7) the silver graphite powder is re-proportioned after the silver content is detected, and the silver graphite product is produced by feeding; feeding qualified silver powder to serve as a silver layer of an electrical contact multilayer product; and (3) taking the qualified silver ingots I and II as raw materials of pure silver ingots to be put into production of silver-based electrical contact products.
The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.
Claims (4)
1. The method for recovering the silver graphite waste is characterized by comprising the following steps of:
s1, crushing: putting the silver graphite waste into a crucible for heating and smelting, and stirring to break the silver graphite waste into silver graphite powder I and molten silver liquid;
s2, separation: firstly, taking out the silver graphite powder I floating on the silver liquid, then casting the silver liquid into a silver ingot I, and cooling the taken out silver graphite powder I to room temperature;
s3, screening silver graphite powder: setting the frequency A of a grading wheel of the jet mill and the pressure a of compressed air, and sieving the cooled silver graphite powder I in the jet mill to obtain silver graphite powder II; the frequency A of the grading wheel is 100-150Hz, and the pressure a of compressed air is 0.1-0.2 MPa;
s4, screening silver powder: setting the frequency B of a grading wheel of the jet mill and the pressure B of compressed air, and continuously sieving by the jet mill to obtain silver powder I, wherein the frequency B of the grading wheel is 10-25Hz, and the pressure B of the compressed air is 0.6-0.7 MPa;
s5, recovering silver scraps: and taking out the silver scraps which cannot be sieved in the jet mill equipment, putting the silver scraps into a crucible, and smelting and casting the silver scraps into silver ingots II.
2. The method for recovering silver graphite waste according to claim 1, characterized in that: the silver graphite waste is one or a mixture of powder, filiform, rod-shaped and cylindrical cake-shaped.
3. The method for recovering silver graphite waste according to claim 1, characterized in that: the smelting temperature in the step S1 is 960-1400 ℃.
4. A method for recycling a recycled material obtained by the recycling method according to claim 1, characterized by: after detecting the silver content of the silver graphite powder II, mixing the silver graphite powder II with silver powder and graphite powder according to a proportion formula, and feeding to produce a silver graphite product; feeding qualified silver powder I as a silver layer of an electrical contact multilayer product; and putting the qualified silver ingots I and II as pure silver ingot raw materials into the production of the silver-based electrical contact product.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202011204322.XA CN112481499B (en) | 2020-11-02 | 2020-11-02 | Method for recycling and reusing silver graphite waste |
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| CN202011204322.XA CN112481499B (en) | 2020-11-02 | 2020-11-02 | Method for recycling and reusing silver graphite waste |
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| CN112481499B CN112481499B (en) | 2022-07-15 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113500170A (en) * | 2021-07-13 | 2021-10-15 | 桂林金格电工电子材料科技有限公司 | Method for mixing and recycling silver tin oxide indium oxide waste and silver graphite waste |
| CN113512645A (en) * | 2021-07-13 | 2021-10-19 | 桂林金格电工电子材料科技有限公司 | Method for mixing and recycling silver tin oxide waste and silver graphite waste |
-
2020
- 2020-11-02 CN CN202011204322.XA patent/CN112481499B/en active Active
Non-Patent Citations (1)
| Title |
|---|
| 王永根等: "挤压型银石墨边角料银回收工艺", 《电工材料》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113500170A (en) * | 2021-07-13 | 2021-10-15 | 桂林金格电工电子材料科技有限公司 | Method for mixing and recycling silver tin oxide indium oxide waste and silver graphite waste |
| CN113512645A (en) * | 2021-07-13 | 2021-10-19 | 桂林金格电工电子材料科技有限公司 | Method for mixing and recycling silver tin oxide waste and silver graphite waste |
| CN113512645B (en) * | 2021-07-13 | 2023-02-24 | 桂林金格电工电子材料科技有限公司 | Method for mixing and recycling silver tin oxide waste and silver graphite waste |
| CN113500170B (en) * | 2021-07-13 | 2023-05-05 | 桂林金格电工电子材料科技有限公司 | Method for mixed recycling of silver tin oxide indium oxide waste and silver graphite waste |
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| CN112481499B (en) | 2022-07-15 |
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