CN110760679A - Method for recovering palladium from silver electrolyte purification slag - Google Patents
Method for recovering palladium from silver electrolyte purification slag Download PDFInfo
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- CN110760679A CN110760679A CN201911053309.6A CN201911053309A CN110760679A CN 110760679 A CN110760679 A CN 110760679A CN 201911053309 A CN201911053309 A CN 201911053309A CN 110760679 A CN110760679 A CN 110760679A
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- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 title claims abstract description 355
- 229910052763 palladium Inorganic materials 0.000 title claims abstract description 178
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 title claims abstract description 119
- 229910052709 silver Inorganic materials 0.000 title claims abstract description 118
- 239000004332 silver Substances 0.000 title claims abstract description 118
- 239000002893 slag Substances 0.000 title claims abstract description 70
- 238000000746 purification Methods 0.000 title claims abstract description 47
- 239000003792 electrolyte Substances 0.000 title claims abstract description 36
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000002386 leaching Methods 0.000 claims abstract description 69
- 239000002253 acid Substances 0.000 claims abstract description 62
- 238000001556 precipitation Methods 0.000 claims abstract description 58
- 238000005406 washing Methods 0.000 claims abstract description 57
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 40
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 31
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 29
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 29
- 238000011084 recovery Methods 0.000 claims abstract description 26
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 23
- JQPTYAILLJKUCY-UHFFFAOYSA-N palladium(ii) oxide Chemical compound [O-2].[Pd+2] JQPTYAILLJKUCY-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910003445 palladium oxide Inorganic materials 0.000 claims abstract description 12
- 230000003472 neutralizing effect Effects 0.000 claims abstract description 6
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 6
- 235000011121 sodium hydroxide Nutrition 0.000 claims abstract description 6
- 238000006243 chemical reaction Methods 0.000 claims description 48
- 238000003756 stirring Methods 0.000 claims description 47
- 239000000243 solution Substances 0.000 claims description 41
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 36
- 239000007787 solid Substances 0.000 claims description 35
- 230000035484 reaction time Effects 0.000 claims description 28
- 238000010438 heat treatment Methods 0.000 claims description 15
- MUBZPKHOEPUJKR-UHFFFAOYSA-N oxalic acid group Chemical group C(C(=O)O)(=O)O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 15
- 239000003638 chemical reducing agent Substances 0.000 claims description 10
- 239000011259 mixed solution Substances 0.000 claims description 10
- 239000007864 aqueous solution Substances 0.000 claims description 9
- 230000008021 deposition Effects 0.000 claims description 7
- 230000000694 effects Effects 0.000 claims description 6
- 239000010970 precious metal Substances 0.000 claims description 6
- NWZSZGALRFJKBT-KNIFDHDWSA-N (2s)-2,6-diaminohexanoic acid;(2s)-2-hydroxybutanedioic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O.NCCCC[C@H](N)C(O)=O NWZSZGALRFJKBT-KNIFDHDWSA-N 0.000 claims description 5
- GSFSVEDCYBDIGW-UHFFFAOYSA-N 2-(1,3-benzothiazol-2-yl)-6-chlorophenol Chemical compound OC1=C(Cl)C=CC=C1C1=NC2=CC=CC=C2S1 GSFSVEDCYBDIGW-UHFFFAOYSA-N 0.000 claims description 5
- 238000005660 chlorination reaction Methods 0.000 claims description 5
- ZOOODBUHSVUZEM-UHFFFAOYSA-N ethoxymethanedithioic acid Chemical compound CCOC(S)=S ZOOODBUHSVUZEM-UHFFFAOYSA-N 0.000 claims description 5
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine monohydrate Substances O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 5
- 238000006386 neutralization reaction Methods 0.000 claims description 5
- 235000006408 oxalic acid Nutrition 0.000 claims description 5
- 235000021110 pickles Nutrition 0.000 claims description 5
- 238000005554 pickling Methods 0.000 claims description 5
- 239000012991 xanthate Substances 0.000 claims description 5
- DKAGJZJALZXOOV-UHFFFAOYSA-N hydrate;hydrochloride Chemical compound O.Cl DKAGJZJALZXOOV-UHFFFAOYSA-N 0.000 claims description 2
- 238000000926 separation method Methods 0.000 claims description 2
- 238000003828 vacuum filtration Methods 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 238000000151 deposition Methods 0.000 description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 4
- 238000005868 electrolysis reaction Methods 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- TUZCOAQWCRRVIP-UHFFFAOYSA-N butoxymethanedithioic acid Chemical compound CCCCOC(S)=S TUZCOAQWCRRVIP-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000003795 desorption Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000011549 displacement method Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- KBKGVINMNSFFOO-UHFFFAOYSA-N silver hydrochloride Chemical compound Cl.[Ag] KBKGVINMNSFFOO-UHFFFAOYSA-N 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
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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
- C22B7/006—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
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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
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
- C22B3/065—Nitric acids or salts thereof
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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
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical 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
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Abstract
The invention discloses a method for recovering palladium from silver electrolyte purification residues, which comprises the following steps: neutralizing the silver electrolyte with caustic soda flakes to obtain silver purification slag containing noble metals such as silver, palladium and the like; leaching the obtained purification slag by nitric acid to obtain a solution containing silver and palladium; adding a palladium precipitation agent into the obtained leaching solution containing the silver and the palladium for palladium precipitation to obtain palladium-rich residues; roasting the palladium-rich slag after two times of weak acid washing and one time of water washing to obtain palladium oxide slag; acid leaching the obtained palladium oxide slag by using nitric acid; the recovery method is adopted to recover palladium, so that the process of palladium recovery is greatly shortened, the direct recovery rate and the recovery rate of palladium are obviously improved, the invention not only effectively recovers palladium, but also reduces the harm of palladium in silver electrolyte, and ensures the production quality of silver ingots.
Description
Technical Field
The invention relates to the technical field of precious metal recovery, in particular to a method for recovering palladium from silver electrolyte purification residues.
Background
In the silver electrolysis process, 30-50% of palladium in the silver anode plate is dissolved into the electrolyte, and after electrolysis for a plurality of cycles, Pd in the electrolyte2+The mass concentration is enriched to 200-400 mg/L, the metal palladium is reduced to metal palladium and is precipitated on a cathode, the quality of a silver product is influenced, and at present, methods for recovering palladium from a silver electrolyte mainly comprise a concentration roasting method, a hydrochloric acid silver-depositing-copper/iron displacement method, an activated carbon adsorption method and a butyl xanthate precipitation method.
The existing concentration roasting method and the existing hydrochloric acid silver precipitation-copper/iron replacement method have the disadvantages of complex operation, more silver loss and easy generation of toxic gas, and the obtained palladium product contains more impurities; the activated carbon adsorption method needs pretreatment, desorption and regeneration, the palladium adsorption efficiency is low, a large amount of silver is also adsorbed, and the desorption solution needs impurity removal and enrichment to obtain a palladium product; the butyl xanthate precipitation method has wide selectivity, a large amount of silver is coprecipitated, the obtained palladium product is impure and is not beneficial to subsequent refining and purification, and the precipitated liquid returns to silver electrolysis to generate adverse effect and produce unqualified silver powder. Therefore, an efficient palladium precipitation agent which can effectively improve the palladium precipitation rate is searched for efficient separation, which is beneficial to the recovery of palladium.
Disclosure of Invention
The invention provides a method for recovering palladium from silver electrolyte purification residues, which can effectively solve the problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme: a method for recovering palladium from silver electrolyte purification slag comprises the following steps:
s1, neutralizing the silver electrolyte with caustic soda flakes to obtain silver purification slag containing noble metals such as silver, palladium and the like;
s2, leaching the obtained silver purification slag by nitric acid to obtain a solution containing silver and palladium, and returning the acid leaching slag to a silver recovery system;
s3, adding a palladium precipitation agent into the obtained leaching solution containing silver and palladium for palladium precipitation to obtain palladium-rich residues, and returning the palladium-precipitated solution to a silver recovery system after chlorination silver precipitation;
s4, roasting the palladium-rich slag after two times of weak acid washing and one time of water washing to obtain palladium oxide slag;
s5, acid leaching the obtained palladium oxide slag by using nitric acid;
and S6, reducing the obtained pickle liquor by using a reducing agent to obtain sponge palladium.
According to the technical scheme, in the step S1, the silver electrolyte is subjected to caustic soda flake neutralization treatment, and the end point pH is controlled to be 8-10.
According to the technical scheme, in the step S2, the specific operation conditions of acid leaching of the silver purification slag are as follows: the reaction temperature is 70-85 ℃, the reaction time is 1-2 h, the stirring speed is 300-400 rpm, the liquid-solid ratio is 3-5: 1, and the pH value of the reaction end point is controlled to be 1.5-3;
the specific operation steps of the acid leaching of the silver purification slag are as follows: uniformly mixing the silver purification slag and nitric acid, heating the mixed solution, controlling the reaction temperature to be 70-85 ℃, reacting for 1-2 hours, continuously stirring the mixed solution by using a stirrer in the reaction process, controlling the stirring speed to be 300-400 rpm, and controlling the liquid-solid ratio to be 3-5: 1.
According to the technical scheme, in the step S3, the palladium precipitation agent is mainly an organic precious metal trapping agent with a high-efficiency palladium precipitation effect, such as sodium dimethyldithiocarbamate and xanthate.
According to the above technical solution, in the step S3, the specific operating conditions of the palladium deposition are as follows: the addition amount of the palladium precipitation agent is 3-6 times of the mass of palladium, the reaction temperature is 60-80 ℃, the reaction time is 0.5-2.0 h, and the stirring speed is 300-400 rpm.
According to the technical scheme, in the step S3, the specific operation steps of the palladium deposition are as follows:
A. pouring the leaching solution containing silver and palladium into a 2L beaker;
B. adding a palladium precipitation agent, heating a beaker, and controlling the reaction temperature of the leaching solution containing silver and palladium and the palladium precipitation agent to be 60-80 ℃;
C. and after the beaker is heated, fully stirring the leaching solution containing the silver and the palladium precipitation agent by a stirrer, wherein the stirring speed is controlled to be 300-400 rpm, and the reaction time is controlled to be 0.5-2.0 h.
According to the above technical solution, in the step S4, the specific operation conditions of the acid washing and the water washing are as follows: preparing hydrochloric acid aqueous solution with the pH value of 1.0-1.5 by using hydrochloric acid, wherein the dosage liquid-solid ratio of pickling solution is 8-10: 1 each time, the clear water liquid-solid ratio is 8-10: 1 each time of washing, the roasting temperature is 700-1000 ℃, and the roasting time is 2-4 h.
According to the technical scheme, in the step S4, the specific operation steps of acid washing and water washing are as follows:
a. preparing a 2L beaker into a hydrochloric acid water solution with the pH value of 1.0-1.5 by using hydrochloric acid;
b. adding the palladium-rich residues into a beaker for weak acid washing, controlling the liquid-solid ratio to be 8-10: 1, and carrying out weak acid washing twice according to the steps;
c. washing the palladium-rich slag subjected to the two weak acid pickups with clear water, and controlling the liquid-solid ratio to be 8-10: 1;
d. roasting the palladium-rich slag subjected to the two weak acid pickups and the one water washing, controlling the roasting temperature to be 700-1000 ℃, and roasting for 2-4 h.
According to the technical scheme, in the step S5, the acid leaching is nitric acid leaching, and the specific leaching operation conditions are as follows: the reaction temperature is 70-85 ℃, the reaction time is 1-2 h, the stirring speed is 300-400 rpm, the liquid-solid ratio is 3-5: 1, and the acidity at the end point of the reaction is controlled to be 20-80 g/L;
in the step S5, the leaching specifically includes: and (4) adding the palladium oxide residue obtained in the step (S4) and nitric acid into a beaker, heating to 70-85 ℃, stirring by a stirrer at a stirring speed of 300-400 rpm at a liquid-solid ratio of 3-5: 1, controlling the reaction time to be 1-2 h after stirring, and controlling the acidity at the reaction end point to be 20-80 g/L.
According to the technical scheme, in the step S6, the reducing agent is oxalic acid or hydrazine hydrate.
Compared with the prior art, the invention has the beneficial effects that: the recovery method is adopted to recover the palladium, so that the recovery process of the palladium is greatly shortened, the reaction rate is high, the recovery rate of the palladium is improved, the damage of the palladium in the silver electrolyte is reduced, and the production quality of silver ingots is ensured.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.
In the drawings:
FIG. 1 is a flow chart of the steps of the recovery process of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
Example 1: as shown in fig. 1, the invention provides a technical scheme of a method for recovering palladium from silver electrolyte purification slag, which comprises the following steps:
s1, neutralizing the silver electrolyte with caustic soda flakes to obtain silver purification slag containing noble metals such as silver, palladium and the like;
s2, leaching the obtained silver purification slag by nitric acid to obtain a solution containing silver and palladium, and returning the acid leaching slag to a silver recovery system;
s3, adding a palladium precipitation agent into the obtained leaching solution containing silver and palladium for palladium precipitation to obtain palladium-rich residues, and returning the palladium-precipitated solution to a silver recovery system after chlorination silver precipitation;
s4, roasting the palladium-rich slag after two times of weak acid washing and one time of water washing to obtain palladium oxide slag;
s5, acid leaching the obtained palladium oxide slag by using nitric acid;
and S6, reducing the obtained pickle liquor by using a reducing agent to obtain sponge palladium.
According to the technical scheme, in step S1, the silver electrolyte is subjected to caustic soda flake neutralization treatment, and the end point pH is controlled to be 8.
According to the technical scheme, in the step S2, the specific operation conditions of acid leaching of the silver purification slag are as follows: the reaction temperature is 70 ℃, the reaction time is 1h, the stirring speed is 300rpm, the liquid-solid ratio is 3:1, and the pH value of the reaction end point is controlled to be 1.5;
the specific operation steps of the acid leaching of the silver purification slag comprise: uniformly mixing the silver purification slag and nitric acid, heating the mixed solution, controlling the reaction temperature to be 70 ℃, reacting for 1h, continuously stirring the mixed solution by using a stirrer in the reaction process, controlling the stirring speed to be 300rpm, and controlling the liquid-solid ratio to be 3: 1.
According to the technical scheme, in the step S3, the palladium precipitation agent is mainly an organic precious metal trapping agent with high-efficiency palladium precipitation effect, such as sodium dimethyldithiocarbamate and xanthate.
According to the technical scheme, in the step S3, the specific operating conditions for depositing palladium are as follows: the addition amount of the palladium precipitation agent is 3 times of the mass of the palladium, the reaction temperature is 60 ℃, the reaction time is 0.5h, and the stirring speed is 300 rpm.
According to the technical scheme, in the step S3, the specific operation steps of palladium deposition are as follows:
A. pouring the leaching solution containing silver and palladium into a 2L beaker;
B. adding a palladium precipitation agent, and heating a beaker to control the reaction temperature of the leaching solution containing silver and palladium and the palladium precipitation agent to be 60 ℃;
C. after the beaker is heated, the leaching solution containing the silver and the palladium is fully stirred with the palladium precipitation agent by a stirrer, the stirring speed is controlled to be 300rpm, and the reaction time is controlled to be 0.5 h.
According to the technical scheme, in the step S4, the specific operation conditions of acid washing and water washing are as follows: preparing hydrochloric acid aqueous solution with pH of 1.5 by using hydrochloric acid, wherein the using amount of pickling solution is 8:1 per time, the using amount of clear water is 8:1 per time of washing, the roasting temperature is 700 ℃, and the roasting time is 4 hours.
According to the technical scheme, in the step S4, the specific operation steps of acid washing and water washing are as follows:
a. preparing a 2L beaker into a hydrochloric acid aqueous solution with the pH value of 1.5 by using nitric acid;
b. adding the palladium-rich residue into a beaker for weak acid washing, controlling the liquid-solid ratio to be 8:1, and carrying out weak acid washing twice according to the steps;
c. washing the palladium-rich slag subjected to the two weak acid pickups with clear water, and controlling the liquid-solid ratio to be 8: 1;
d. roasting the palladium-rich slag subjected to the two weak acid pickings and the one water washing, and controlling the roasting temperature to be 700 ℃.
According to the technical scheme, in the step S5, the acid leaching is performed by adopting nitric acid leaching, and the specific leaching operation conditions are as follows: the reaction temperature is 70 ℃, the reaction time is 1h, the stirring speed is 300rpm, the liquid-solid ratio is 3:1, and the acidity at the end point of the reaction is controlled to be 20 g/L;
in step S5, the leaching specifically includes: and (3) adding the palladium oxide residue obtained in the step (S4) and nitric acid into a beaker, heating to 70 ℃, stirring by a stirrer at the stirring speed of 300rpm and the liquid-solid ratio of 3:1, controlling the reaction time to be 1h after stirring, and controlling the acidity at the end point of the reaction to be 20 g/L.
According to the technical scheme, in the step S6, the reducing agent is oxalic acid or hydrazine hydrate.
Example 2: as shown in fig. 1, the invention provides a technical scheme of a method for recovering palladium from silver electrolyte purification slag, which comprises the following steps:
s1, neutralizing the silver electrolyte with caustic soda flakes to obtain silver purification slag containing noble metals such as silver, palladium and the like;
s2, leaching the obtained silver purification slag by nitric acid to obtain a solution containing silver and palladium, and returning the acid leaching slag to a silver recovery system;
s3, adding a palladium precipitation agent into the obtained leaching solution containing silver and palladium for palladium precipitation to obtain palladium-rich residues, and returning the palladium-precipitated solution to a silver recovery system after chlorination silver precipitation;
s4, roasting the palladium-rich slag after two times of weak acid washing and one time of water washing to obtain palladium oxide slag;
s5, acid leaching the obtained palladium oxide slag by using nitric acid;
and S6, reducing the obtained pickle liquor by using a reducing agent to obtain sponge palladium.
According to the technical scheme, in step S1, the silver electrolyte is subjected to caustic soda flake neutralization treatment, and the end point pH is controlled to be 9.
According to the technical scheme, in the step S2, the specific operation conditions of acid leaching of the silver purification slag are as follows: the reaction temperature is 78 ℃, the reaction time is 1.5h, the stirring speed is 350rpm, the liquid-solid ratio is 4:1, and the pH value of the reaction end point is controlled to be 2.2;
the specific operation steps of the acid leaching of the silver purification slag comprise: uniformly mixing the silver purification slag and nitric acid, heating the mixed solution, controlling the reaction temperature to be 78 ℃, reacting for 1.5h, continuously stirring the mixed solution by using a stirrer in the reaction process, controlling the stirring speed to be 350rpm, and controlling the liquid-solid ratio to be 4: 1.
According to the technical scheme, in the step S3, the palladium precipitation agent is mainly an organic precious metal trapping agent with high-efficiency palladium precipitation effect, such as sodium dimethyldithiocarbamate and xanthate.
According to the technical scheme, in the step S3, the specific operating conditions for depositing palladium are as follows: the addition amount of the palladium precipitation agent is 4.5 times of the mass of the palladium, the reaction temperature is 70 ℃, the reaction time is 1.0h, and the stirring speed is 350 rpm.
According to the technical scheme, in the step S3, the specific operation steps of palladium deposition are as follows:
A. pouring the leaching solution containing silver and palladium into a 2L beaker;
B. adding a palladium precipitation agent, and heating a beaker to control the reaction temperature of the leaching solution containing silver and palladium and the palladium precipitation agent to be 70 ℃;
C. after the beaker is heated, the leaching solution containing the silver and the palladium is fully stirred with the palladium precipitation agent by a stirrer, the stirring speed is controlled to be 350rpm, and the reaction time is controlled to be 0.7 h.
According to the technical scheme, in the step S4, the specific operation conditions of acid washing and water washing are as follows: preparing hydrochloric acid aqueous solution with the pH value of 1.7 by using hydrochloric acid, wherein the using amount of pickling solution is 9:1 each time, the using amount of clear water is 9:1 each time of washing, the roasting temperature is 840 ℃, and the roasting time is 3 hours.
According to the technical scheme, in the step S4, the specific operation steps of acid washing and water washing are as follows:
a. preparing a 2L beaker into a hydrochloric acid aqueous solution with the pH value of 1.7 by using hydrochloric acid;
b. adding the palladium-rich residue into a beaker for weak acid washing, controlling the liquid-solid ratio to be 9:1, and carrying out weak acid washing twice according to the steps;
c. washing the palladium-rich slag subjected to the two weak acid pickups with clear water, and controlling the liquid-solid ratio to be 9: 1;
d. roasting the palladium-rich slag subjected to the two weak acid pickings and the one water washing, and controlling the roasting temperature to be 840 ℃.
According to the technical scheme, in the step S5, the acid leaching is performed by adopting nitric acid leaching, and the specific leaching operation conditions are as follows: the reaction temperature is 77 ℃, the reaction time is 1.5h, the stirring speed is 350rpm, the liquid-solid ratio is 4:1, and the acidity of the reaction end point is controlled to be 50 g/L;
in step S5, the leaching specifically includes: and (3) adding the palladium oxide residue obtained in the step (S4) and nitric acid into a beaker, heating to 77 ℃, stirring by a stirrer, controlling the stirring speed to be 350rpm and the liquid-solid ratio to be 4:1, controlling the reaction time to be 1.5h after stirring, and controlling the acidity at the reaction end point to be 50 g/L.
According to the technical scheme, in the step S6, the reducing agent is oxalic acid or hydrazine hydrate.
Example 3: as shown in fig. 1, the invention provides a technical scheme of a method for recovering palladium from silver electrolyte purification slag, which comprises the following steps:
s1, neutralizing the silver electrolyte with caustic soda flakes to obtain silver purification slag containing noble metals such as silver, palladium and the like;
s2, leaching the obtained silver purification slag by nitric acid to obtain a solution containing silver and palladium, and returning the acid leaching slag to a silver recovery system;
s3, adding a palladium precipitation agent into the obtained leaching solution containing silver and palladium for palladium precipitation to obtain palladium-rich residues, and returning the palladium-precipitated solution to a silver recovery system after chlorination silver precipitation;
s4, roasting the palladium-rich slag after two times of weak acid washing and one time of water washing to obtain palladium oxide slag;
s5, acid leaching the obtained palladium oxide slag by using nitric acid;
and S6, reducing the obtained pickle liquor by using a reducing agent to obtain sponge palladium.
According to the above technical solution, in step S1, the silver electrolyte is subjected to caustic soda flake neutralization treatment, and the end point pH is controlled to 10.
According to the technical scheme, in the step S2, the specific operation conditions of acid leaching of the silver purification slag are as follows: the reaction temperature is 85 ℃, the reaction time is 2h, the stirring speed is 400rpm, the liquid-solid ratio is 5:1, and the pH value of the reaction end point is controlled to be 3;
the specific operation steps of the acid leaching of the silver purification slag comprise: uniformly mixing the silver purification slag and nitric acid, heating the mixed solution, controlling the reaction temperature to be 85 ℃, reacting for 2 hours, continuously stirring the mixed solution by using a stirrer in the reaction process, controlling the stirring speed to be 400rpm, and controlling the liquid-solid ratio to be 5: 1.
According to the technical scheme, in the step S3, the palladium precipitation agent is mainly an organic precious metal trapping agent with high-efficiency palladium precipitation effect, such as sodium dimethyldithiocarbamate and xanthate.
According to the technical scheme, in the step S3, the specific operating conditions for depositing palladium are as follows: the addition amount of the palladium precipitation agent is 6 times of the mass of the palladium, the reaction temperature is 80 ℃, the reaction time is 2 hours, and the stirring speed is 400 rpm.
According to the technical scheme, in the step S3, the specific operation steps of palladium deposition are as follows:
A. pouring the leaching solution containing silver and palladium into a 2L beaker;
B. adding a palladium precipitation agent, and heating a beaker to control the reaction temperature of the leaching solution containing silver and palladium and the palladium precipitation agent to be 80 ℃;
C. after the beaker is heated, the leaching solution containing the silver and the palladium is fully stirred with the palladium precipitation agent by a stirrer, the stirring speed is controlled to be 400rpm, and the reaction time is controlled to be 1 h.
According to the technical scheme, in the step S4, the specific operation conditions of acid washing and water washing are as follows: preparing hydrochloric acid aqueous solution with pH of 2 by using hydrochloric acid, wherein the using amount of the pickling solution is 10:1 per time, the using amount of the clear water is 10:1 per time of washing, the roasting temperature is 1000 ℃, and the roasting time is 2 hours.
According to the technical scheme, in the step S4, the specific operation steps of acid washing and water washing are as follows:
a. preparing a 2L beaker into a hydrochloric acid aqueous solution with the pH value of 2 by using hydrochloric acid;
b. adding the palladium-rich residue into a beaker for weak acid washing, controlling the liquid-solid ratio to be 10:1, and carrying out weak acid washing twice according to the steps;
c. washing the palladium-rich slag subjected to the two weak acid pickups with clear water, and controlling the liquid-solid ratio to be 10: 1;
d. roasting the palladium-rich slag subjected to the two weak acid pickings and the one water washing, and controlling the roasting temperature to be 1000 ℃.
According to the technical scheme, in the step S5, the acid leaching is performed by adopting nitric acid leaching, and the specific leaching operation conditions are as follows: the reaction temperature is 85 ℃, the reaction time is 2 hours, the stirring speed is 400rpm, the liquid-solid ratio is 5:1, and the acidity at the end point of the reaction is controlled to be 80 g/L;
in step S5, the leaching specifically includes: and (3) adding the palladium oxide residue obtained in the step (S4) and nitric acid into a beaker, heating to 85 ℃, stirring by a stirrer at the stirring speed of 400rpm and the liquid-solid ratio of 5:1, controlling the reaction time to be 2h after stirring, and controlling the acidity at the reaction end point to be 80 g/L.
According to the technical scheme, in the step S6, the reducing agent is oxalic acid or hydrazine hydrate.
The results of the palladium precipitation rate, which were measured by the temperature, the amount of the palladium precipitation agent added and the reaction time in the palladium precipitation step in example 1, example 2 and example 3, are shown in table 1:
TABLE 1 Palladium precipitation Rate of high efficiency Palladium precipitating agent
By testing the roasting temperature and the roasting reaction time in the roasting step of the high-palladium slag in the embodiment 1, the embodiment 2 and the embodiment 3, the palladium grade result of the roasting slag is shown in the table 2:
TABLE 2 Palladium grade of roasting residue
As can be seen from tables 1 and 2, the recovery method controls the temperature in the palladium precipitation step to be 70 ℃, the ratio of the addition amount of the palladium precipitation agent to the mass of palladium to be 4.5 times, and the reaction time to be 1.0h, so that the palladium precipitation rate can reach 99.12%, and the roasting residue has the highest palladium grade and low loss rate when the roasting temperature is about 800 ℃, and further shows that the recovery method can improve the recovery rate of palladium.
Based on the technical scheme, the invention has the beneficial effects that: the recovery method is adopted to recover the palladium, so that the recovery process of the palladium is greatly shortened, the reaction rate is high, the recovery rate of the palladium is improved, the damage of the palladium in the silver electrolyte is reduced, and the production quality of silver ingots is ensured.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for recovering palladium from silver electrolyte purification slag is characterized by comprising the following steps: the method comprises the following steps:
s1, neutralizing the silver electrolyte with caustic soda flakes to obtain silver purification slag containing noble metals such as silver, palladium and the like;
s2, leaching the obtained silver purification slag by nitric acid to obtain a solution containing silver and palladium, and returning the acid leaching slag to a silver recovery system;
s3, adding a palladium precipitation agent into the obtained leaching solution containing silver and palladium for palladium precipitation to obtain palladium-rich residues, and returning the palladium-precipitated solution to a silver recovery system after chlorination silver precipitation;
s4, roasting the palladium-rich slag after two times of weak acid washing and one time of water washing to obtain palladium oxide slag;
s5, acid leaching the obtained palladium oxide slag by using nitric acid;
and S6, reducing the obtained pickle liquor by using a reducing agent to obtain sponge palladium.
2. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: and in the step S1, carrying out caustic soda flake neutralization treatment on the silver electrolyte, and controlling the end point pH to be 8-10.
3. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: in the step S2, the specific operation conditions of acid leaching of the silver purification slag are as follows: leaching with nitric acid, wherein the reaction temperature is 70-85 ℃, the reaction time is 1-2 h, the stirring speed is 300-400 rpm, the liquid-solid ratio is 3-5: 1, and the pH value of the reaction end point is controlled to be 1.5-3;
the specific operation steps of the acid leaching of the silver purification slag are as follows: uniformly mixing a nitric acid aqueous solution and the silver purification slag, heating the mixed solution, controlling the reaction temperature to be 70-85 ℃, reacting for 1-2 hours, continuously stirring the mixed solution by using a stirrer in the reaction process, controlling the stirring speed to be 300-400 rpm, and controlling the liquid-solid ratio to be 3-5: 1.
4. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: in the step S3, the palladium precipitation agent is mainly an organic precious metal trapping agent with a high-efficiency palladium precipitation effect, such as sodium dimethyldithiocarbamate and xanthate.
5. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: in the step S3, the specific operating conditions of the palladium deposition are as follows: the addition amount of the palladium precipitation agent is 3-6 times of the mass of palladium, the reaction temperature is 60-80 ℃, the reaction time is 0.5-2.0 h, and the stirring speed is 300-400 rpm.
6. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: in the step S3, the specific operation steps of the palladium deposition are as follows:
A. pouring the leaching solution containing silver and palladium into a 2L beaker;
B. adding a palladium precipitation agent, and simultaneously heating the beaker to control the reaction temperature of the leaching solution containing silver and palladium and the palladium precipitation agent to be 60-80 ℃;
C. and after the beaker is heated, fully stirring the leaching solution containing the silver and the palladium precipitation agent by a stirrer, wherein the stirring speed is controlled to be 300-400 rpm, and the reaction time is controlled to be 0.5-2.0 h. And after the reaction is finished, carrying out liquid-solid separation by using vacuum filtration equipment to obtain the high-palladium slag.
7. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: in step S4, the specific operating conditions of the acid washing and the water washing are as follows: preparing hydrochloric acid aqueous solution with the pH value of 1.0-1.5 by using hydrochloric acid, wherein the dosage liquid-solid ratio of pickling solution is 8-10: 1 each time, the clear water liquid-solid ratio is 8-10: 1 each time of washing, the roasting temperature is 700-1000 ℃, and the roasting time is 2-4 h.
8. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: in step S4, the specific operation steps of acid washing and water washing are as follows:
a. preparing a 2L beaker into a hydrochloric acid water solution with the pH value of 1.0-1.5 by using hydrochloric acid;
b. adding the palladium-rich residues into a beaker for weak acid washing, controlling the liquid-solid ratio to be 8-10: 1, and carrying out weak acid washing twice according to the steps;
c. washing the palladium-rich slag subjected to the two weak acid pickups with clear water, and controlling the liquid-solid ratio to be 8-10: 1;
d. roasting the palladium-rich slag subjected to the two weak acid pickups and the one water washing, controlling the roasting temperature to be 700-1000 ℃, and roasting for 2-4 h.
9. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: in the step S5, the acid leaching is nitric acid leaching, and the specific leaching operation conditions are as follows: the reaction temperature is 70-85 ℃, the reaction time is 1-2 h, the stirring speed is 300-400 rpm, the liquid-solid ratio is 3-5: 1, and the acidity at the end point of the reaction is controlled to be 20-80 g/L;
in the step S5, the leaching specifically includes: and (4) adding the palladium oxide residue obtained in the step (S4) and nitric acid into a beaker, heating to 70-85 ℃, stirring by a stirrer at a stirring speed of 300-400 rpm at a liquid-solid ratio of 3-5: 1, controlling the reaction time to be 1-2 h after stirring, and controlling the acidity at the reaction end point to be 20-80 g/L.
10. The method for recovering palladium from silver electrolyte purification residues as claimed in claim 1, wherein: in step S6, the reducing agent is oxalic acid, hydrazine hydrate, or the like.
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| CN113802008A (en) * | 2021-09-16 | 2021-12-17 | 兰州大学 | Method for treating waste liquid containing platinum group noble metal |
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| CN117049971A (en) * | 2023-08-22 | 2023-11-14 | 株洲环冠新材料科技有限公司 | Amino modified material and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113802008A (en) * | 2021-09-16 | 2021-12-17 | 兰州大学 | Method for treating waste liquid containing platinum group noble metal |
| CN113969355A (en) * | 2021-09-27 | 2022-01-25 | 铜陵有色设计研究院有限责任公司 | Short-process preparation process for preparing zinc-cadmium alloy by using organic cobalt slag |
| CN117049971A (en) * | 2023-08-22 | 2023-11-14 | 株洲环冠新材料科技有限公司 | Amino modified material and preparation method and application thereof |
| CN117049971B (en) * | 2023-08-22 | 2024-04-09 | 株洲环冠新材料科技有限公司 | Amino modified material and preparation method and application thereof |
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