CN114293018A - Method for recovering various rare and noble metals from waste circuit board - Google Patents
Method for recovering various rare and noble metals from waste circuit board Download PDFInfo
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- CN114293018A CN114293018A CN202210030186.XA CN202210030186A CN114293018A CN 114293018 A CN114293018 A CN 114293018A CN 202210030186 A CN202210030186 A CN 202210030186A CN 114293018 A CN114293018 A CN 114293018A
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- 239000002699 waste material Substances 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 title claims abstract description 42
- 229910000510 noble metal Inorganic materials 0.000 title abstract description 6
- 238000002386 leaching Methods 0.000 claims abstract description 114
- 229910052751 metal Inorganic materials 0.000 claims abstract description 48
- 239000002184 metal Substances 0.000 claims abstract description 48
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 28
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 27
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 26
- 229910052737 gold Inorganic materials 0.000 claims abstract description 17
- 239000010970 precious metal Substances 0.000 claims abstract description 16
- 229910052709 silver Inorganic materials 0.000 claims abstract description 16
- 150000002739 metals Chemical class 0.000 claims abstract description 15
- 238000004064 recycling Methods 0.000 claims abstract description 14
- 239000000243 solution Substances 0.000 claims description 51
- 239000010949 copper Substances 0.000 claims description 47
- 239000003153 chemical reaction reagent Substances 0.000 claims description 34
- 239000007788 liquid Substances 0.000 claims description 28
- 238000003756 stirring Methods 0.000 claims description 26
- 239000007787 solid Substances 0.000 claims description 21
- 238000001914 filtration Methods 0.000 claims description 19
- 238000000605 extraction Methods 0.000 claims description 18
- 239000000706 filtrate Substances 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 13
- 238000004070 electrodeposition Methods 0.000 claims description 11
- 239000013078 crystal Substances 0.000 claims description 10
- 238000003723 Smelting Methods 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- 230000001580 bacterial effect Effects 0.000 claims description 6
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 claims description 6
- 239000011259 mixed solution Substances 0.000 claims description 6
- 230000003647 oxidation Effects 0.000 claims description 6
- 238000007254 oxidation reaction Methods 0.000 claims description 6
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 claims description 5
- 239000012141 concentrate Substances 0.000 claims description 5
- 238000001704 evaporation Methods 0.000 claims description 5
- 239000012452 mother liquor Substances 0.000 claims description 5
- 238000007781 pre-processing Methods 0.000 claims description 5
- 238000010008 shearing Methods 0.000 claims description 4
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 3
- 229910000365 copper sulfate Inorganic materials 0.000 claims description 3
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 claims description 3
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 claims description 3
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 claims description 3
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 3
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 claims description 3
- 229910000360 iron(III) sulfate Inorganic materials 0.000 claims description 3
- 239000003350 kerosene Substances 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims 3
- 239000010793 electronic waste Substances 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 4
- 239000011135 tin Substances 0.000 description 56
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 31
- 238000011084 recovery Methods 0.000 description 23
- 239000010931 gold Substances 0.000 description 16
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 230000035484 reaction time Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000000197 pyrolysis Methods 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 239000004332 silver Substances 0.000 description 4
- 229910052718 tin Inorganic materials 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 229910021607 Silver chloride Inorganic materials 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000010944 silver (metal) Substances 0.000 description 2
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
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- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000001698 pyrogenic effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
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Abstract
The invention belongs to the technical field of waste resource recycling, and particularly relates to a method for recycling various rare and precious metals from waste circuit boards; separating and leaching Sn, leaching Cu in the circuit board, subsequently leaching and recovering Al, Ni and Zn respectively, and finally leaching and recovering Au and Ag; when the method is used for recovering all rare and noble metals from the waste circuit board, the metals can be sequentially and orderly leached, the rare and noble metals in the circuit board are recovered in a gradient manner, a key green recycling technology of waste resources is formed, the waste resources can be recycled, and the harm of electronic wastes such as the waste circuit board to the environment is reduced.
Description
Technical Field
The invention belongs to the technical field of waste resource recycling, and particularly relates to a method for recycling various rare and precious metals from waste circuit boards.
Background
In recent years, with the rapid growth and development of the electronic industry, a large amount of electronic waste is generated. The waste circuit board is used as an important component of electronic waste, contains various recyclable rare and precious metals such as copper, nickel, aluminum, tin, gold, silver and the like, and accounts for about 40% in total, so that the waste circuit board has high resource recycling value.
At present, the treatment method of the waste circuit board mainly comprises the technologies of mechanical treatment, chemical treatment, pyrogenic treatment, pyrolysis treatment and the like. The treatment methods have the defects of large investment, easy generation of toxic, harmful and other wastes in the operation process, less metal recovery types, incapability of realizing the step separation leaching of Sn, Cu, Al, Ni, Zn, Au and Ag, and difficulty in realizing the thorough extraction and separation of metals.
Therefore, how to effectively treat various rare and precious metals in the waste circuit board to enable the rare and precious metals to be sequentially and orderly leached and recovered with high efficiency and have higher comprehensive recovery utilization rate of secondary resources becomes a key research direction.
Disclosure of Invention
In order to overcome the problems, the invention provides a method for recovering various rare and precious metals from waste circuit boards, the reagent formula is simple, the metals in the existing circuit boards can be efficiently recovered, the step separation leaching and recovery of the metals are realized, the types of the recovered metals are more, the metal leaching rate and the recovery rate are higher, the reutilization maximization of waste resources can be realized, and the large-scale industrialized recovery can be carried out.
In order to achieve the technical purpose, the technical scheme of the invention is realized as follows:
a method for recovering various rare and precious metals from waste circuit boards comprises the following steps:
step one, preprocessing a circuit board:
the method comprises the following steps of splitting and sorting circuit boards, and shearing and crushing selected circuit boards to obtain circuit board particles;
and step two, leaching and recovering Sn:
placing the circuit board particles obtained in the step one in a stirring container, adding a Sn leaching reagent into the container at normal temperature and normal pressure to enable the liquid-solid ratio in the container to be 5:1, keeping the pH value to be 1.0-2.0, leaching for 6-8 h under the stirring condition, then filtering the mixed solution to obtain Sn-rich filtrate and filter residue, settling, evaporating and concentrating the Sn-rich filtrate to obtain mixed crystals containing Sn, enabling the crystals to enter a Sn smelting plant in the form of Sn concentrate to recover metal Sn, and returning evaporated mother liquor to the stirring container for recycling;
wherein the Sn leaching reagent is one or more of copper sulfate, copper nitrate and copper chloride solution, wherein Cu in the Sn leaching reagent is ensured2+The concentration is 15-25 g/L;
leaching and recovering Cu:
adding a leaching reagent into the filter residue obtained in the second step at normal temperature and normal pressure, ensuring that the liquid-solid ratio is 5:1 and the pH value is 1.0-2.0, leaching for 8-10 h under the condition of stirring, filtering the mixed solution after leaching is finished, and recovering Cu from the obtained filtrate by adopting an extraction-back extraction-electrodeposition method;
leaching and recovering Al, Ni and Zn:
adding a leaching reagent into the filter residue filtered in the third step to ensure that the liquid-solid ratio is 5:1 and the pH value is 1.0-2.0, leaching for 6-8 h under the conditions of normal temperature and pressure and stirring, filtering after leaching to obtain a pregnant solution containing Al, Ni and Zn and filter residue, and respectively recovering Al, Ni and Zn through the pregnant solution;
wherein the leaching reagent used in the third step and the fourth step is one or more of ferric chloride, ferric nitrate or ferric sulfate solution, so that Fe in the leaching reagent3+The concentration is 25-30 g/L;
leaching and recovering Au and Ag:
and (3) adding the aqua regia into the filter residue obtained after filtering in the step four, and ensuring that the liquid-solid ratio is 5:1, leaching for 3-5 h at normal temperature and normal pressure under stirring, filtering after leaching to obtain pregnant solution and filter residue, and respectively recovering Au and Ag from the pregnant solution.
In the first step, the circuit board is crushed to the granularity of 0.5mm-1.0 mm.
The Sn leaching reagent used in the step two is Cu-containing2+Or a leachate containing Cu2+The waste bacterial oxidation liquid.
The leaching reagent used in the third step and the fourth step is Fe-containing3+Or containing Fe3+The waste bacterial oxidation liquid.
The third step of recovering Cu by adopting an extraction-reextraction-electrodeposition method specifically comprises the following steps:
adding 10% of extraction liquid by volume fraction into the filtrate containing Cu, so that the volume ratio of the extraction liquid to the filtrate is 1: 1, extracting for 5min, standing, layering, separating, and adding a stripping solution, namely a sulfuric acid solution with a volume fraction of 10%, into the extraction liquid to ensure that the volume ratio of the extraction liquid to the stripping solution is 1: 1, the back extraction time is 5min, and Cu is obtained2+The noble liquid of (3) is subjected to electrodeposition to obtain metal Cu.
The extractant is LIX984, and is dissolved by using 260# kerosene to prepare an extraction liquid with the volume fraction of 10%.
The invention has the beneficial effects that:
when the rare and precious metals are recovered from the waste circuit board, the soldering tin in the circuit board is dissolved and then recovered, and after the Sn metal is removed, the low-melting-point metal does not influence the subsequent leaching and recovery of the rest metals, so that necessary conditions are provided for the leaching of the metals.
The leaching rate and the recovery rate of each rare noble metal are high, and the metal in the circuit board can be separated and recovered in a gradient manner, so that the full-component recovery and the full-element utilization are realized; the method realizes green and efficient cleaning treatment of the waste circuit boards, comprehensively recovers urban mineral products, and provides key technology and contribution force for developing recycling economy and resource recycling industry.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.
FIG. 1 is a flow chart of the method of the present invention.
FIG. 2 shows SEM test results of recovering Sn metal from circuit board.
FIG. 3 shows SEM-EDS test results of the present invention for recovering Sn metal from a circuit board.
FIG. 4 shows SEM test results of the invention when recovering Cu metal from circuit boards.
FIG. 5 shows SEM-EDS test results of the present invention when recovering Cu metal from circuit boards.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
As shown in fig. 1, a method for recovering a plurality of rare and precious metals from waste circuit boards comprises the following steps:
step one, preprocessing a circuit board:
the circuit boards are split and sorted, and the selected circuit boards are cut and crushed to obtain required circuit board particles;
wherein the sorting of the circuit boards is as follows: it is necessary to simply pre-treat the components on the circuit board to remove plastic, iron pieces, etc., leaving a portion high in precious metal content.
And step two, leaching and recovering Sn:
placing the circuit board particles obtained in the step one in a stirring container, adding a Sn leaching reagent into the container at normal temperature and normal pressure, and extracting metal Sn in the circuit board in a wet leaching way, wherein the method specifically comprises the following steps: the liquid-solid ratio in the container is 5:1, the pH value is kept between 1.0 and 2.0, the Sn-rich filtrate and the filter residue are obtained by leaching for 6 to 8 hours under the condition of stirring, then the mixed solution is filtered, the Sn-rich filtrate and the filter residue are obtained, the Sn-rich filtrate is settled, evaporated and concentrated to obtain mixed crystals containing Sn, the crystals enter a Sn smelting plant in the form of Sn concentrate for recovering metal Sn, and the evaporation mother liquor is returned to the stirring container for recycling;
wherein the Sn leaching reagent is one or more of copper sulfate, copper nitrate and copper chloride solution, wherein Cu in the Sn leaching reagent is ensured2+The concentration is 15-25 g/L;
leaching and recovering Cu:
adding a leaching reagent into the filter residue obtained in the second step at normal temperature and normal pressure, ensuring that the liquid-solid ratio is 5:1 and the pH value is 1.0-2.0, leaching for 8-10 h under the condition of stirring, filtering the mixed solution after leaching is finished, and recovering Cu from the obtained filtrate by adopting an extraction-back extraction-electrodeposition method;
leaching and recovering Al, Ni and Zn:
adding a leaching reagent into the filter residue filtered in the third step in a continuous leaching manner to ensure that the liquid-solid ratio is 5:1 and the pH value is 1.0-2.0, leaching for 6-8 h under the conditions of normal temperature and pressure and stirring, leaching Al, Ni and Zn, filtering after leaching is finished to obtain a pregnant solution containing Al, Ni and Zn and filter residue, and respectively recovering Al, Ni and Zn through the pregnant solution;
wherein the leaching reagent used in the third step and the fourth step is one or more of ferric chloride, ferric nitrate or ferric sulfate solution, so that Fe in the leaching reagent3+The concentration is 25-30 g/L;
the step adopts a continuous leaching mode to carry out a second-stage reaction, and adopts the same leaching reagent and process parameters, and after Cu in the material is preferentially leached, Al, Ni and Zn begin to be leached in succession, so that the second-stage leaching is carried out. Cu-containing substances produced in one stage, i.e. after the reaction in step three2+The pregnant solution can be used as a leaching reagent of the metal Sn and is returned to extract the metal Sn, so that the cyclic utilization of the liquid is realized.
Leaching and recovering Au and Ag:
and (3) adding the aqua regia into the filter residue obtained after filtering in the step four, and ensuring that the liquid-solid ratio is 5:1, leaching for 3-5 h at normal temperature and normal pressure under stirring, filtering after leaching to obtain pregnant solution and filter residue, and respectively recovering Au and Ag from the pregnant solution.
Finally, metal Sn, Cu, Al, Ni, Zn, Au and Ag in the circuit board material is subjected to gradient separation leaching, and the utilization of waste resources is maximized.
In the first step, the circuit board is crushed to the granularity of 0.5mm-1.0 mm.
The Sn leaching reagent used in the step two is Cu-containing2+Or a leachate containing Cu2+The waste bacterial oxidation liquid.
The leaching reagent used in the third step and the fourth step can also contain Fe3+Or containing Fe3+The waste bacterial oxidation liquid.
The third step of recovering Cu by adopting an extraction-reextraction-electrodeposition method specifically comprises the following steps:
adding 10% of extraction liquid by volume fraction into the filtrate containing Cu, so that the volume ratio of the extraction liquid to the filtrate is 1: 1, extracting for 5min, standing, layering, separating, and adding a stripping solution, namely a sulfuric acid solution with a volume fraction of 10%, into the extraction liquid to ensure that the volume ratio of the extraction liquid to the stripping solution is 1: 1, the back extraction time is 5min, and Cu is obtained2+Is expensiveAnd (4) electrodepositing the pregnant solution to obtain the metal Cu.
Wherein Cu is ensured during electrodeposition2+If the concentration is more than 30g/L, if Cu2+If the concentration is less than 30g/L, the pregnant solution is evaporated and concentrated, or the leachate is reused to make Cu2+The concentration reached 30g/L and was filtered again.
The extractant is LIX984, and is dissolved by using 260# kerosene to prepare an extraction liquid with the volume fraction of 10%.
So that the manner in which the features, advantages, differences, and innovations of the present invention are attained and can be understood and appreciated more fully by the reader, the present invention is further described below in connection with a series of embodiments.
Example 1
In this embodiment, a method for recovering a plurality of rare and precious metals from a waste circuit board includes the following steps:
(1) preprocessing a circuit board: and (3) splitting, sorting and shearing the circuit board, and crushing to 0.5-1.0 mm to obtain waste circuit board particles.
The main metal content in the waste circuit board particles is shown in the following table 1:
TABLE 1 content of main metals in waste circuit board particles
| Type of metal | Content (%) |
| Sn | 6.17 |
| Cu | 39.42 |
| Al | 6.36 |
| Ni | 0.37 |
| Zn | 4.23 |
| Au* | 14.88 |
| Ag* | 42.61 |
Note: units are g/t.
(2) Leaching and recovering of Sn: extracting metal Sn in the circuit board in a stirring leaching mode, and adding the Sn leaching reagent into a reaction container to ensure that the rotating speed is 300r/min, and the liquid-solid ratio is 5:1, the pH value is 1.0, the reaction time is 6 hours, and a Sn-rich solution and filter residue A are obtained. And (3) recovering Sn: and settling, evaporating and concentrating the Sn-rich solution to obtain mixed crystals of Sn-containing compounds, feeding the crystals into a Sn smelting plant in the form of Sn concentrate, recovering the Sn metal, and returning the evaporated mother liquor to a leaching tank for recycling.
(3) Leaching and recovering of Cu: adding the leaching reagent into the filter residue A to extract metal Cu, and extracting the Cu in the circuit board by adopting a wet leaching method, wherein the liquid-solid ratio is 5:1, carrying out continuous leaching under the conditions that the pH value is 1.0, the rotating speed is 300r/min and the reaction time is 8h to obtain a Cu-containing solution and filter residue B, and realizing the recovery of Cu according to the Cu recovery method.
(4) Leaching and recovering Al, Ni and Zn: and continuously extracting the filter residue B, leaching Al, Ni and Zn in the circuit board by using the leaching reagent in a continuous leaching mode, wherein corresponding technological parameters are leaching under the condition of stirring, the liquid-solid ratio is 5:1, the pH value is 1.0, the leaching time is 6h at normal temperature and normal pressure, and the precious liquid containing Al, Ni and Zn and the filter residue C are obtained.
And (3) recovering Al: adding an alkaline material into the pregnant solution containing Al, Ni and Zn obtained in the fourth step, adjusting the pH value to 3.5-4.0, stirring for 0.5h, filtering, and separating solid from liquid to obtain Al (OH)3Precipitation and corresponding pregnant solution containing Ni and Zn; part of Al still exists in the part of pregnant solution, and the part of pregnant solution needs to be concentrated, collected and added with alkali materials for secondary recovery in the actual process, or the part of pregnant solution is added into new pregnant solution containing Al, Ni and Zn for circulation treatment; recovering the second recovered Al (OH)3Precipitation and primary recovery of the resulting Al (OH)3The precipitates enter a smelting plant together.
And (3) recovering Ni: recovering Ni by electrodeposition, collecting noble liquid containing Ni and Zn, adjusting pH to 1.0-3.0, and controlling current density at 200A/m2-350A/m2Carrying out electrodeposition under the condition that the reaction time is 1.5h to obtain metal Ni;
and (3) recovering Zn: and (3) recovering metal Zn from the Zn-containing precious liquid after Ni recovery by adopting a pyrolysis method, placing the Zn-containing precious liquid in pyrolysis equipment, setting the temperature to be 550 ℃, continuously reacting for 45min, feeding the obtained pyrolysis liquid into a vacuum separator, and condensing and collecting Zn on a cold plate in the vacuum separator to realize Zn recovery.
(5) Leaching and recovering Au and Ag: and (3) adding aqua regia solution (concentrated nitric acid: concentrated hydrochloric acid in a volume ratio of 1: 3) into the filter residue C, wherein the corresponding process parameters are that the liquid-solid ratio is 5:1, the stirring speed is 300r/min, and the leaching time is 3 h.
And (3) recovering gold: adding a reducing agent, namely sodium sulfite, into the pregnant solution obtained after filtration to adjust the potential to be less than 400mV, stirring and filtering to obtain a pregnant solution containing Ag and gold powder, washing, removing impurities, filtering and drying the gold powder, and further casting ingots;
and (3) recovering silver: adding NaCl (in a molar ratio of 1.3: 1) into the Ag-containing pregnant solution, precipitating Ag into AgCl, adding hydrochloric acid to adjust the pH value to 0.8-1.2, adding iron powder into the AgCl precipitate to obtain silver powder, washing the silver powder, removing impurities, filtering, drying, and further casting ingots.
In this example, the leaching rates of the metals are: sn: 98. cu: 98. al: 95. ni: 98. zn: 98. au: 99. ag: 98.
the recovery rates of the metals in this example were: sn: 98. cu: 99. al: 95. ni: 97. zn: 97. au: 99. ag: 99.
example 2
As shown in fig. 2 to 5, in this embodiment, a method for recovering a plurality of rare and noble metals from waste circuit boards includes the following steps:
(1) preprocessing a circuit board: and (3) splitting, sorting and shearing the circuit board, and crushing to 0.5-1.0 mm to obtain waste circuit board particles.
The main metal content in the waste circuit board particles is shown in table 2 below:
TABLE 2 content of main metals in waste circuit board particles
| Type of metal | Content (%) |
| Sn | 6.17 |
| Cu | 39.42 |
| Al | 6.36 |
| Ni | 0.37 |
| Zn | 4.23 |
| Au* | 14.88 |
| Ag* | 42.61 |
Note: units are g/t.
(2) Leaching and recovering of Sn: extracting metal Sn in the circuit board in a stirring leaching mode, adding the Sn leaching reagent into a reaction container, and adding a solvent into the reaction container, wherein the solvent has a liquid-solid ratio of 5:1, the pH value is 2.0, the rotating speed is 300r/min, the reaction time is 8h, and Sn-rich solution and filter residue A are obtained. And (3) recovering Sn: and settling, evaporating and concentrating the Sn-rich solution to obtain mixed crystals of Sn-containing compounds, feeding the crystals into a Sn smelting plant in the form of Sn concentrate, recovering the Sn metal, and returning the evaporated mother liquor to a leaching tank for recycling.
(3) Leaching and recovering of Cu: adding the leaching reagent into the filter residue A to extract metal Cu, and extracting the Cu in the circuit board by adopting a wet leaching method to ensure that the liquid-solid ratio is 5:1, continuously leaching at the pH value of 2.0 and the rotating speed of 300r/min for 10 hours to obtain a Cu-containing solution and filter residue B; and the recovery of Cu is realized according to the Cu recovery method.
(4) Leaching and recovering Al, Ni and Zn: and continuously extracting the filter residue B, leaching Al, Ni and Zn in the circuit board by using the leaching reagent in a continuous leaching mode, wherein corresponding technological parameters are leaching under the condition of stirring, the liquid-solid ratio is 5:1, the pH value is 2.0, the leaching time is 8 hours at normal temperature and normal pressure, and the precious liquid containing Al, Ni and Zn and the filter residue C are obtained.
Recovery of Al, Ni and Zn: the Al, Ni and Zn were recovered by the method of example 1.
(5) Leaching and recovering Au and Ag: and (3) adding aqua regia solution (concentrated nitric acid: concentrated hydrochloric acid in a volume ratio of 1: 3) into the filter residue C, wherein the corresponding process parameters are that the liquid-solid ratio is 5:1, the stirring speed is 300r/min, and the reaction time is 5 h.
And (3) recovering gold: the gold recovery process of example 1 was followed to effect the recovery of gold.
And (3) recovering silver: silver recovery was achieved as in example 1.
In this example, the leaching rates of the metals are: sn: 98. cu: 98. al: 95. ni: 98. zn: 98. au: 99. ag: 97.
the recovery rates of the metals in this example were: sn: 98. cu: 99. al: 95. ni: 97. zn: 97. au: 99. ag: 99.
and leaching and recovering the metal in the waste circuit board according to the specific embodiment. The result shows that in the test process, Sn is firstly separated and leached, then Cu in the circuit board is leached, and then Al, Ni and Zn are leached and recovered respectively, and finally Au and Ag are leached and recovered. Through analysis and test, the leaching rate and the recovery rate of each metal are both more than 95%. From the above contents and conclusions, it can be seen that when the method is used for recovering rare and precious metals from waste circuit boards, the metals can be sequentially and orderly leached, the rare and precious metals in the circuit boards are recovered in a gradient manner, a key green recycling technology of waste resources is further formed, the waste resources can be recycled, and the harm of electronic wastes such as the waste circuit boards to the environment is reduced.
In the above description, the present invention is an example of the present invention, and has a certain uniqueness, but not all embodiments of the present invention are not limited thereto, and the design and technical idea of the present invention have various modifications and combinations within a certain range, and the present invention can be implemented in a wide range, and should also be within the scope of the present invention.
Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the scope of the present invention is not limited to the specific details of the above embodiments, and any person skilled in the art can substitute or change the technical solution of the present invention and its inventive concept within the technical scope of the present invention, and these simple modifications belong to the scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (6)
1. A method for recovering various rare and precious metals from waste circuit boards is characterized by comprising the following steps:
step one, preprocessing a circuit board:
the method comprises the following steps of splitting and sorting circuit boards, and shearing and crushing selected circuit boards to obtain circuit board particles;
and step two, leaching and recovering Sn:
placing the circuit board particles obtained in the step one in a stirring container, adding a Sn leaching reagent into the container at normal temperature and normal pressure to enable the liquid-solid ratio in the container to be 5:1, keeping the pH value to be 1.0-2.0, leaching for 6-8 h under the stirring condition, then filtering the mixed solution to obtain Sn-rich filtrate and filter residue, settling, evaporating and concentrating the Sn-rich filtrate to obtain mixed crystals containing Sn, enabling the crystals to enter a Sn smelting plant in the form of Sn concentrate to recover metal Sn, and returning evaporated mother liquor to the stirring container for recycling;
wherein the Sn leaching reagent is one or more of copper sulfate, copper nitrate and copper chloride solution, wherein Cu in the Sn leaching reagent is ensured2+The concentration is 15-25 g/L;
leaching and recovering Cu:
adding a leaching reagent into the filter residue obtained in the second step at normal temperature and normal pressure, ensuring that the liquid-solid ratio is 5:1 and the pH value is 1.0-2.0, leaching for 8-10 h under the condition of stirring, filtering the mixed solution after leaching is finished, and recovering Cu from the obtained filtrate by adopting an extraction-back extraction-electrodeposition method;
leaching and recovering Al, Ni and Zn:
adding a leaching reagent into the filter residue filtered in the third step to ensure that the liquid-solid ratio is 5:1 and the pH value is 1.0-2.0, leaching for 6-8 h under the conditions of normal temperature and pressure and stirring, filtering after leaching to obtain a pregnant solution containing Al, Ni and Zn and filter residue, and respectively recovering Al, Ni and Zn through the pregnant solution;
wherein the leaching reagent used in the third step and the fourth step is one or more of ferric chloride, ferric nitrate or ferric sulfate solution, so that Fe in the leaching reagent3+The concentration is 25-30 g/L;
leaching and recovering Au and Ag:
and (3) adding the aqua regia into the filter residue obtained after filtering in the step four, and ensuring that the liquid-solid ratio is 5:1, leaching for 3-5 h at normal temperature and normal pressure under stirring, filtering after leaching to obtain pregnant solution and filter residue, and respectively recovering Au and Ag from the pregnant solution.
2. The method for recovering rare metals from waste circuit boards as claimed in claim 1, wherein the circuit boards are crushed to a particle size of 0.5mm-1.0mm in the first step.
3. The method as claimed in claim 1, wherein the Sn leaching agent used in the second step is Cu-containing2+Or a leachate containing Cu2+The waste bacterial oxidation liquid.
4. The method for recovering rare and precious metals from waste circuit boards as claimed in claim 1, wherein the leaching agent used in the third and fourth steps is Fe-containing leaching agent3+Or containing Fe3+The waste bacterial oxidation liquid.
5. The method for recovering a plurality of rare and precious metals from waste circuit boards according to claim 2, wherein the step three of recovering Cu by an extraction-stripping-electrodeposition method comprises the following specific steps:
adding 10% of extraction liquid by volume fraction into the filtrate containing Cu, so that the volume ratio of the extraction liquid to the filtrate is 1: 1, extractTaking for 5min, standing, layering, separating, and adding stripping solution, i.e. 10% sulfuric acid solution by volume fraction, into the extraction solution to make the volume ratio of the extraction solution to the stripping solution be 1: 1, the back extraction time is 5min, and Cu is obtained2+The noble liquid of (3) is subjected to electrodeposition to obtain metal Cu.
6. The method as claimed in claim 5, wherein the extractant is LIX984, which is dissolved by 260# kerosene and is configured as 10% volume fraction of the extract.
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