CN114410981A - Method for refining gold and silver - Google Patents
Method for refining gold and silver Download PDFInfo
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- CN114410981A CN114410981A CN202210079664.6A CN202210079664A CN114410981A CN 114410981 A CN114410981 A CN 114410981A CN 202210079664 A CN202210079664 A CN 202210079664A CN 114410981 A CN114410981 A CN 114410981A
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- gold
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 title claims abstract description 250
- 239000010931 gold Substances 0.000 title claims abstract description 232
- 229910052737 gold Inorganic materials 0.000 title claims abstract description 227
- 229910052709 silver Inorganic materials 0.000 title claims abstract description 154
- 239000004332 silver Substances 0.000 title claims abstract description 154
- 238000000034 method Methods 0.000 title claims abstract description 50
- 238000007670 refining Methods 0.000 title claims abstract description 41
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims abstract description 169
- 230000009467 reduction Effects 0.000 claims abstract description 106
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 55
- 238000001914 filtration Methods 0.000 claims abstract description 37
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000000460 chlorine Substances 0.000 claims abstract description 29
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 29
- 238000005266 casting Methods 0.000 claims abstract description 27
- 238000002386 leaching Methods 0.000 claims abstract description 23
- 238000011084 recovery Methods 0.000 claims abstract description 23
- 238000001816 cooling Methods 0.000 claims abstract description 15
- 238000005868 electrolysis reaction Methods 0.000 claims abstract description 8
- 238000003756 stirring Methods 0.000 claims description 52
- 238000006243 chemical reaction Methods 0.000 claims description 46
- WTDHULULXKLSOZ-UHFFFAOYSA-N Hydroxylamine hydrochloride Chemical compound Cl.ON WTDHULULXKLSOZ-UHFFFAOYSA-N 0.000 claims description 44
- 239000000706 filtrate Substances 0.000 claims description 31
- 238000005660 chlorination reaction Methods 0.000 claims description 27
- 230000035484 reaction time Effects 0.000 claims description 22
- 238000001035 drying Methods 0.000 claims description 21
- 239000003792 electrolyte Substances 0.000 claims description 21
- 238000010438 heat treatment Methods 0.000 claims description 21
- 238000005406 washing Methods 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 239000003638 chemical reducing agent Substances 0.000 claims description 17
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 15
- 239000007800 oxidant agent Substances 0.000 claims description 15
- 230000001590 oxidative effect Effects 0.000 claims description 15
- 230000008569 process Effects 0.000 claims description 15
- 238000003723 Smelting Methods 0.000 claims description 14
- 239000012065 filter cake Substances 0.000 claims description 14
- 239000007788 liquid Substances 0.000 claims description 14
- 238000002844 melting Methods 0.000 claims description 14
- 230000008018 melting Effects 0.000 claims description 14
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 claims description 14
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical group CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 claims description 12
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 11
- 239000010936 titanium Substances 0.000 claims description 11
- 229910052719 titanium Inorganic materials 0.000 claims description 11
- 238000005303 weighing Methods 0.000 claims description 11
- 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 9
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine monohydrate Substances O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 claims description 9
- 229910001961 silver nitrate Inorganic materials 0.000 claims description 7
- 239000000126 substance Substances 0.000 claims description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 3
- 229910045601 alloy Inorganic materials 0.000 claims description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 2
- 239000011707 mineral Substances 0.000 claims description 2
- 239000000243 solution Substances 0.000 description 34
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 16
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 16
- 238000001514 detection method Methods 0.000 description 11
- 229910021607 Silver chloride Inorganic materials 0.000 description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 9
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 9
- 235000010265 sodium sulphite Nutrition 0.000 description 8
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 230000036541 health Effects 0.000 description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000011946 reduction process Methods 0.000 description 3
- KZVBBTZJMSWGTK-UHFFFAOYSA-N 1-[2-(2-butoxyethoxy)ethoxy]butane Chemical compound CCCCOCCOCCOCCCC KZVBBTZJMSWGTK-UHFFFAOYSA-N 0.000 description 2
- PTTPXKJBFFKCEK-UHFFFAOYSA-N 2-Methyl-4-heptanone Chemical compound CC(C)CC(=O)CC(C)C PTTPXKJBFFKCEK-UHFFFAOYSA-N 0.000 description 2
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 2
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 2
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 235000006408 oxalic acid Nutrition 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- FFRBMBIXVSCUFS-UHFFFAOYSA-N 2,4-dinitro-1-naphthol Chemical compound C1=CC=C2C(O)=C([N+]([O-])=O)C=C([N+]([O-])=O)C2=C1 FFRBMBIXVSCUFS-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 230000000844 anti-bacterial effect Effects 0.000 description 1
- -1 artware Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000012864 cross contamination Methods 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000033116 oxidation-reduction process Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- BSWGGJHLVUUXTL-UHFFFAOYSA-N silver zinc Chemical compound [Zn].[Ag] BSWGGJHLVUUXTL-UHFFFAOYSA-N 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 235000010269 sulphur dioxide Nutrition 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
- 230000007306 turnover Effects 0.000 description 1
Images
Classifications
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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
- C22B11/06—Chloridising
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/16—Making metallic powder or suspensions thereof using chemical processes
- B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
- B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
-
- 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
-
- 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
-
- 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
-
- 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
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C5/00—Electrolytic production, recovery or refining of metal powders or porous metal masses
- C25C5/02—Electrolytic production, recovery or refining of metal powders or porous metal masses from solutions
-
- 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 gold and silver refining method, which comprises the following steps: preparing a gold splashing sheet, preparing a dilute hydrochloric acid solution, chloridizing and leaching, removing chlorine, cooling, filtering, carrying out primary gold reduction, carrying out gold casting, carrying out secondary gold reduction, carrying out silver electrolysis, and casting a silver ingot; the recovery rate of gold can reach 99.97%, the purity of the obtained finished gold ingot is not lower than 99.99%, the finished gold ingot meets the national standard I gold standard, silver in filter residue can be recovered and purified while gold is refined and purified, the recovery rate of silver can reach 99.88%, the purity of the obtained finished silver ingot is not lower than 99.99%, and the finished silver ingot meets the national standard I silver standard; the gold and silver refining method provided by the invention is safe, efficient and environment-friendly, and has higher economic value and practical value.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to a method for refining gold and silver.
Background
Gold, the No. 79 element in the periodic table of elements, and the chemical element symbol of Au, is a noble metal with soft texture, stable chemical property and golden yellow color, and has wide application in the gold ornamental industry, the currency storage industry, the electronic industry, the aerospace industry and the pharmaceutical industry. At present, the refining method of gold mainly includes an electrolytic method, an extraction method, a aqua regia method, and a Boliden method (chlorination method).
The refining process of the electrolytic method mainly takes the crude gold as an anode, direct current is supplied to a chloride system to dissolve the anode crude gold, and pure gold is separated out from a cathode, the electrolytic method has the advantages of stable gold product quality and purification purity of over 99.99 percent, but the requirement on raw material quality is strict (usually, the requirement on the purity of the crude gold is over 90 percent); the technical requirement is high; the treatment period is long; the process has the defects of great gold overstocked, great inconvenience for capital turnover and subsequent security and defense work and the like.
The extraction method is that the crude gold is dissolved by aqua regia and then extracted by an extractant, then the loaded organic phase is directly back extracted to produce high-quality gold powder, the adopted extractant comprises DBC (dibutyl carbitol), MIBK (methyl isobutyl ketone), DIBK (diisobutyl ketone) and diethyl ether, and the adopted back extractant is an acidic solution containing oxalic acid or sodium sulfite. Compared with an electrolytic method, the extraction method has the advantages of short generation period, no gold overstocking in the process, high recovery rate, low technical requirement and simple operation, but has obvious defects, such as narrow selection range of an extracting agent, large reagent consumption, great pollution to the environment caused by production, poor labor environment and difficult waste gas treatment, and the extraction method generally requires that the gold content of a crude gold raw material reaches 80-90%.
The aqua regia method is to dissolve the crushed or pressed crude gold into aqua regia, filter the filtrate and use sodium sulfite, ferrous sulfate, sulfur dioxide, hydroxylamine hydrochloride or oxalic acid as a reducing agent to reduce gold in the filtrate to produce national standard No. 1 gold with purity of more than 99.99 percent.
Compared with the aqua regia method, the chlorination method avoids the use of nitric acid, does not generate nitrogen oxides in production, is beneficial to tail gas emission reaching standards, meets the requirement of environmental protection, has stable product quality, but also has the problem of low recovery rate caused by incomplete chlorination leaching and reduction processes, and simultaneously has the health hidden trouble caused by volatilization and escape of toxic gases such as chlorine, sulfur dioxide and the like. Therefore, further improvements to the chlorination process are of interest in the field.
On the other hand, most of the gold mine enterprises are concerned only with refining and purifying the gold in the crude gold, common impurities such as silver in the crude gold are generally treated as waste materials, and silver (Ag) is used as a precious metal with excellent chemical stability and mechanical property, and is widely applied to the fields of photoelectric materials, decorative materials, artware, composite materials, silver paste, energy industry (silver-zinc batteries, fuel cells, hydrogen energy, nuclear energy and solar energy utilization), catalysts, medical drugs, antibacterial materials and the like, which is undoubtedly a great resource waste. Therefore, in the refining of the crude gold, the recovery and purification of silver simultaneously have important economic value and practical value.
Disclosure of Invention
In view of the above, the invention provides a safe, environment-friendly and efficient gold and silver refining method, which improves the traditional chlorination method, on one hand, sodium chlorate is used as an oxidant to replace chlorine gas adopted by the conventional chlorination method, so that crude gold can be better chloridized and leached, the pollution of chlorine gas escape to the environment and the health threat of personnel are reduced, on the other hand, hydroxylamine hydrochloride is used to replace the traditional sulfur dioxide or sodium sulfite in the gold reduction stage, the reduction effect is enhanced, and the gold recovery rate is improved; meanwhile, the silver filter residue generated in the leaching process is recovered and purified, and finally, the gold with the purity not lower than 99.99 percent and the silver with the purity not lower than 99.99 percent can be produced.
In order to achieve the purpose, the invention adopts the following technical scheme:
a gold and silver refining method comprises the following steps:
(1) preparing a gold splashing sheet: smelting the crude gold and gold material at 1150 ℃ to prepare gold sheets with the thickness of 0.03-0.1 mm;
(2) preparing a dilute hydrochloric acid solution: adding concentrated hydrochloric acid and water into a reaction kettle to prepare a dilute hydrochloric acid solution, then starting stirring and heating to 65-80 ℃, wherein the hydrochloric acid content of the dilute hydrochloric acid solution is 180-230 g/L;
(3) chlorination leaching: adding gold flakes into a reaction kettle, then adding an oxidant for chlorination gold leaching, keeping the reaction temperature at 65-80 ℃, and reacting for 1-2 h, wherein the oxidant adding speed is 300-500 g/min, and the mass ratio of the oxidant to the gold flakes is 0.4-0.5: 1;
(4) chlorine removal: raising the temperature of the reaction kettle to be more than 85 ℃, and performing chlorine removal for 10-20 min;
(5) cooling and filtering: after chlorine removal is finished, cooling the reaction kettle, pouring the solution in the kettle into a high-precision pneumatic filter vehicle for filtering, and respectively carrying out a primary gold reduction step and a silver reduction step on the filtrate and filter residue;
(6) primary gold reduction: adding the filtrate obtained in the step (5) into a primary gold reduction kettle, starting stirring and heating to 50-60 ℃, then slowly adding hydroxylamine hydrochloride in batches as a reducing agent to carry out primary gold reduction, wherein the reaction time is 1-2 h, the mass ratio of the consumption of the hydroxylamine hydrochloride to gold flakes is 0.8-1: 1, and the reduction end point potential is controlled to be not less than +650 mv;
(7) gold smelting: filtering the primary reduced gold powder, washing a filter cake with hot water at 40-70 ℃, drying, feeding the filter cake into a melting furnace, casting into a gold ingot, and feeding the filtrate into a secondary gold reduction step;
(8) and (3) secondary gold reduction: adding the filtrate obtained in the step (7) into a secondary gold reduction kettle, starting stirring and heating to 50-60 ℃, then adding excessive hydroxylamine hydrochloride as a reducing agent to carry out secondary gold reduction, wherein the reaction time is 0.5-1 h, the reduction end point potential is controlled to be not higher than +340mv, reacting to obtain secondary reduced gold powder, washing and drying the secondary reduced gold powder, and returning to the step (1);
(9) silver reduction: weighing the filter residue obtained in the step (5), adding the weighed filter residue into a silver reduction kettle, adding water, wherein the solid-to-liquid ratio in the kettle is 1: 4-6, starting stirring, adding an alkaline substance into the kettle to adjust the pH value of feed liquid in the kettle to be more than or equal to 10, then adding hydrazine hydrate to carry out silver reduction, keeping the reaction temperature at 30-50 ℃, reacting for 1-1.5 h, and the mass ratio of the hydrazine hydrate amount to the filter residue is 0.8-1: 1;
(10) silver electrolysis casting of silver ingot: and (4) filtering, washing and drying the reduced silver powder obtained in the step (9), casting a silver anode plate, then hanging the silver anode plate on a silver electrolytic tank anode conducting bar hook, and sleeving an anode bag, wherein the cathode plate is a titanium plate. And (3) starting an electrolyte circulating pump, adding silver nitrate electrolyte into the tank, starting a silver electrolytic rectifier, introducing direct current to start electrolytic refining, controlling the temperature of the electrolyte at 30-45 ℃, and feeding electrolytic silver powder produced by the silver electrolytic refining to a melting furnace to cast into silver ingots.
Further, the crude gold material comprises jewelry gold, industrial gold, alloy gold and ore gold with the grade of 70-99.95%.
Further, in the chlorination leaching process in the step (3), the oxidant is sodium chlorate.
Further, in the gold casting process in the step (7), the gold recovery rate can reach 99.97%, and the cast gold ingot is a standard gold ingot with the purity not lower than 99.99%.
Further, in the silver reduction process in the step (9), the alkaline substance is sodium hydroxide or potassium hydroxide.
Further, in the electrolytic refining process in the step (10), the recovery rate of silver can reach 99.88%, and the obtained silver ingot is a standard silver ingot with the purity not lower than 99.99%.
Compared with the prior art, the invention has the beneficial effects that:
(1) the gold and silver refining method is an improvement on the traditional chlorination refining method, adopts more stable and safe solid sodium chlorate to replace chlorine adopted by the traditional chlorination method as an oxidant, not only can better improve the chlorination leaching effect of the crude gold, but also reduces environmental pollution and personal health damage caused by volatilization escape of excessive chlorine when the chlorine is directly adopted; on the other hand, in the gold reduction process, the adopted reducing agent is hydroxylamine hydrochloride, compared with sulfur dioxide or sodium sulfite adopted by the traditional chlorination method, the reaction effect in the reduction stage can be enhanced, the final recovery rate of gold is improved, the potential safety hazard brought by waste gas generated by the traditional reducing agent can be avoided, and the refining process is more efficient and safer.
(2) The method provided by the invention has the advantages that the silver chloride filter residue generated in the leaching process is recovered and purified while the gold is refined, the gold recovery rate can reach 99.97%, the silver recovery rate can reach 99.88%, and finally the national standard No. one gold with the purity not lower than 99.99% and the national standard No. one silver with the purity not lower than 99.99% can be produced, so that the method provided by the invention has higher resource recovery rate, higher economic value and practical value.
(3) The raw gold material refined by the method has wide sources, comprises the jewelry gold, the industrial gold, the alloy gold and the mineral gold with the grade of 70-99.95%, has strong adaptability, and is very beneficial to large-scale popularization.
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 described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 shows a schematic flow chart of refining and purifying gold and silver in the embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the following embodiments, which are illustrated in the accompanying drawings.
The invention discloses a gold and silver refining method, and figure 1 is a schematic diagram of a gold and silver refining and purifying process in an embodiment of the invention. As shown in fig. 1, the specific steps are as follows:
1) preparing a gold splashing sheet: smelting the crude gold and gold material at 1150 ℃ to prepare gold sheets with the thickness of 0.03-0.1 mm; the gold material splashing sheet with the thickness of 0.03-0.1 mm is manufactured, so that the gold and silver in the crude gold can be wrapped up easily, the crude gold can be in contact reaction with a reagent well, and the chlorination leaching efficiency is improved.
(2) Preparing a dilute hydrochloric acid solution: adding concentrated hydrochloric acid and water into a reaction kettle to prepare a dilute hydrochloric acid solution, then starting stirring and heating to 65-80 ℃, wherein the hydrochloric acid content of the dilute hydrochloric acid solution is 180-230 g/L; too high concentration of hydrochloric acid can cause excessive volatilization of hydrochloric acid gas, corrode equipment, and too low concentration can affect leaching effect, so that the concentration is set to be 180-230 g/L, which is most suitable.
(3) Chlorination leaching: adding gold flakes into a reaction kettle, then adding an oxidant for chlorination gold leaching, keeping the reaction temperature at 65-80 ℃, and reacting for 1-2 h, wherein the oxidant adding speed is 300-500 g/min, and the mass ratio of the oxidant to the gold flakes is 0.4-0.5: 1; setting the stirring speed to be 300 rmp; the oxidant is not added too fast or too slow, too fast can cause the reaction temperature to rise sharply, the material spraying is possible, too slow can cause the oxidant concentration in the solution to be too low, and the reaction is slow.
(4) Chlorine removal: raising the temperature of the reaction kettle to be more than 85 ℃, and performing chlorine removal for 10-20 min; chlorine removal is to remove a small amount of chlorine generated in the oxidation process in advance, so that the phenomenon that the chlorine escapes in the subsequent filtration stage to cause environmental pollution and harm to human health is avoided.
(5) Cooling and filtering: after chlorine removal is finished, cooling the reaction kettle, pouring the solution in the kettle into a high-precision pneumatic filter vehicle for filtering, and respectively carrying out a primary gold reduction step and a silver reduction step on the filtrate and filter residue; the high-precision pneumatic filtering vehicle can accelerate the filtering efficiency, is acid-resistant and corrosion-resistant, and avoids cross contamination to filtrate in the filtering process.
(6) Primary gold reduction: adding the filtrate obtained in the step (5) into a primary gold reduction kettle, starting stirring and heating to 50-60 ℃, then slowly adding hydroxylamine hydrochloride in batches as a reducing agent to carry out primary gold reduction, wherein the reaction time is 1-2 h, the mass ratio of the consumption of the hydroxylamine hydrochloride to gold flakes is 0.8-1: 1, and the reduction end point potential is controlled to be not less than +650 mv; setting the stirring speed to 300rmp, and detecting the oxidation-reduction potential in the system at regular time during the reduction stirring period to ensure that the reduction end point potential is not lower than +650 mv.
(7) Gold smelting: filtering the primary reduced gold powder, washing a filter cake with hot water at 40-70 ℃, drying, feeding the filter cake into a melting furnace, casting into a gold ingot, and feeding the filtrate into a secondary gold reduction step; the gold ingot obtained at this time is national standard No. one gold with the purity not less than 99.99%.
(8) And (3) secondary gold reduction: adding the filtrate obtained in the step (7) into a secondary gold reduction kettle, starting stirring and heating to 50-60 ℃, then adding excessive hydroxylamine hydrochloride as a reducing agent to carry out secondary gold reduction, wherein the reaction time is 0.5-1 h, the reduction end point potential is controlled to be not higher than +340mv, reacting to obtain secondary reduced gold powder, washing and drying the secondary reduced gold powder, and returning to the step (1); excess hydroxylamine hydrochloride means adding hydroxylamine hydrochloride until no more solid gold precipitate is produced in the solution.
(9) Silver reduction: weighing the filter residue obtained in the step (5), adding the weighed filter residue into a silver reduction kettle, adding water, wherein the solid-to-liquid ratio in the kettle is 1: 4-6, starting stirring, adding an alkaline substance into the kettle to adjust the pH value of feed liquid in the kettle to be more than or equal to 10, then adding hydrazine hydrate to carry out silver reduction, keeping the reaction temperature at 30-50 ℃, reacting for 1-1.5 h, and the mass ratio of the hydrazine hydrate amount to the filter residue is 0.8-1: 1; the stirring speed is set to be 300rmp, so that the silver slurry is fully and uniformly stirred, and the silver reduction effect is good.
(10) Silver electrolysis casting of silver ingot: and (4) filtering, washing and drying the reduced silver powder obtained in the step (9), casting a silver anode plate, then hanging the silver anode plate on a silver electrolytic tank anode conducting bar hook, and sleeving an anode bag, wherein the cathode plate is a titanium plate. Starting an electrolyte circulating pump, adding silver nitrate electrolyte into the tank, starting a silver electrolytic rectifier, introducing direct current to start silver electrolytic refining, controlling the temperature of the electrolyte at 30-45 ℃, and feeding electrolytic silver powder produced by silver electrolytic refining to a melting furnace to cast into silver ingots; the silver ingot obtained at this time is national standard silver I with the purity not lower than 99.99 percent.
Example 1
(1) Preparing a gold splashing sheet: weighing 45kg of crude gold material, smelting at 1150 ℃, and preparing a gold sheet with the thickness of 0.03-0.1 mm through a graphite crucible dripping sheet.
(2) Preparing a dilute hydrochloric acid solution: adding concentrated hydrochloric acid and water into a reaction kettle to prepare 225L of dilute hydrochloric acid solution, then starting stirring and heating to 65-80 ℃, wherein the hydrochloric acid content of the dilute hydrochloric acid solution is 180-230 g/L, and the stirring speed is set to be 200 rmp.
(3) Chlorination leaching: adding gold flakes into a 300L titanium reaction kettle, then adding 22kg of sodium chlorate for chlorination gold leaching, keeping the reaction temperature at 65-80 ℃, the reaction time at 1.5h, the adding speed of the sodium chlorate at 300g/min, and setting the stirring speed at 300 rmp.
(4) Chlorine removal: and (3) raising the temperature of the reaction kettle to 90 ℃, and performing chlorine removal for 15 min.
(5) Cooling and filtering: after chlorine removal is finished, cooling the reaction kettle, pouring the solution in the kettle into a high-precision pneumatic filtering vehicle for filtering, and respectively carrying out a gold reduction step and a silver reduction step on the filtrate and the filter residue.
(6) Primary gold reduction: and (3) adding the filtrate obtained in the step (5) into a primary gold reduction kettle, starting stirring and heating to 50 ℃, then slowly adding 41kg of hydroxylamine hydrochloride serving as a reducing agent in batches to perform primary gold reduction, wherein the reaction time is 1.5h, the reduction end point potential is controlled to be +658mv, and the stirring speed is set to be 300 rmp.
(7) Gold smelting: filtering the primary reduced gold powder, washing a filter cake with hot water at 40-70 ℃, drying, feeding the filter cake into a melting furnace, casting into a gold ingot of 43.3kg, and feeding the filtrate into a secondary gold reduction step, wherein the obtained gold ingot is national standard gold I with the purity not lower than 99.99%, and the gold recovery rate is 99.97%.
(8) And (3) secondary gold reduction: and (3) adding the filtrate obtained in the step (7) into a secondary gold reduction kettle, starting stirring and heating to 50 ℃, then adding excessive hydroxylamine hydrochloride as a reducing agent to carry out secondary gold reduction, wherein the reaction time is 0.5h, the reduction end point potential is controlled to be +336mv, reacting to obtain secondary reduced gold powder, washing and drying the secondary reduced gold powder, and returning to the step (1), wherein the excessive hydroxylamine hydrochloride means adding hydroxylamine hydrochloride until no solid gold precipitate is generated in the solution.
(9) Silver reduction: weighing the dry weight of the silver chloride filter residue obtained in the step (5) to be 1.48kg, adding the silver chloride filter residue into a silver reduction kettle, adding water, wherein the solid-to-liquid ratio in the kettle is 1:4, starting stirring, adding sodium hydroxide into the kettle to adjust the pH value of feed liquid in the kettle to be more than or equal to 10, adding 1.23kg of hydrazine hydrate to carry out silver reduction, keeping the reaction temperature at 50 ℃, the reaction time at 1h, and setting the stirring speed at 300rmp to ensure uniform stirring.
(10) Silver electrolysis casting of silver ingot: and (3) filtering, washing and drying the reduced silver powder obtained in the step (9), casting a silver anode plate, then hanging the silver anode plate on a hook of an anode conducting rod of a silver electrolytic tank, sleeving an anode bag, taking a titanium plate as a cathode plate, starting an electrolyte circulating pump, adding silver nitrate electrolyte into the tank, starting a silver electrolytic rectifier, introducing direct current to start electrolytic refining, controlling the temperature of the electrolyte at 45 ℃, sending the electrolytic silver powder produced by the silver electrolytic refining to a melting furnace to cast into 1.11kg of silver ingots, wherein the obtained silver ingots are national standard silver with the purity of not less than 99.99%, and the silver recovery rate is 99.88%.
Elemental content detection analysis was performed on the gold ingot and silver ingot obtained in example 1, and the results are recorded in tables 1 and 2.
TABLE 1 gold ingot element content detection and analysis results
| Au％ | Ag％ | Pb％ | Cu％ |
| 99.9962 | 0.0015 | 0.0001 | 0.0005 |
| Fe％ | Pd％ | Sb％ | Bi％ |
| 0.0006 | 0.0009 | 0.0001 | 0.0001 |
TABLE 2 silver ingot element content detection and analysis results
| Ag％ | Pb％ | Sb％ | Cu％ |
| 99.9978 | 0.0001 | 0.0001 | 0.0006 |
| Fe％ | Pd％ | Bi％ | Te％ |
| 0.0008 | 0.0002 | 0.0002 | 0.0001 |
| Se％ | |||
| 0.0001 |
Comparative example 1
(1) Preparing a gold splashing sheet: weighing 45kg of crude gold material, smelting at 1150 ℃, and preparing a gold sheet with the thickness of 0.03-0.1 mm through a graphite crucible dripping sheet.
(2) Preparing a dilute hydrochloric acid solution: adding concentrated hydrochloric acid and water into a reaction kettle to prepare 225L of dilute hydrochloric acid solution, then starting stirring and heating to 65-80 ℃, wherein the hydrochloric acid content of the dilute hydrochloric acid solution is 180-230 g/L, and the stirring speed is set to be 200 rmp.
(3) Chlorination leaching: adding gold flakes into a 300L titanium reaction kettle, then adding 22kg of sodium chlorate for chlorination gold leaching, keeping the reaction temperature at 65-80 ℃, the reaction time at 1.5h, the adding speed of the sodium chlorate at 300g/min, and setting the stirring speed at 300 rmp.
(4) Chlorine removal: and (3) raising the temperature of the reaction kettle to 90 ℃, and performing chlorine removal for 15 min.
(5) Cooling and filtering: after chlorine removal is finished, cooling the reaction kettle, pouring the solution in the kettle into a high-precision pneumatic filtering vehicle for filtering, and respectively carrying out a gold reduction step and a silver reduction step on the filtrate and the filter residue.
(6) Primary gold reduction: and (3) adding the filtrate obtained in the step (5) into a primary gold reduction kettle, starting stirring and heating to 50 ℃, then slowly adding 41kg of sodium sulfite in batches as a reducing agent to carry out primary gold reduction, wherein the reaction time is 1.5h, the reduction end point potential is controlled to be +660mv, and the stirring speed is set to be 300 rmp.
(7) Gold smelting: filtering the primary reduced gold powder, washing a filter cake with hot water at 40-70 ℃, drying, feeding the filter cake into a melting furnace, casting into 39.1kg of gold ingot, and feeding the filtrate into a secondary gold reduction step, wherein the obtained gold ingot is national standard No. I gold with the purity not lower than 99.99%, and the gold recovery rate is 90.26%.
(8) And (3) secondary gold reduction: and (3) adding the filtrate obtained in the step (7) into a secondary gold reduction kettle, starting stirring and heating to 50 ℃, then adding excessive sodium sulfite as a reducing agent to carry out secondary gold reduction, wherein the reaction time is 0.5h, the reduction end point potential is controlled to be +334mv, reacting to obtain secondary reduced gold powder, washing and drying the secondary reduced gold powder, and returning to the step (1), wherein the excessive sodium sulfite means adding sodium sulfite until no solid gold precipitate is generated in the solution.
(9) Silver reduction: weighing the dry weight of the silver chloride filter residue obtained in the step (5) to be 1.48kg, adding the silver chloride filter residue into a silver reduction kettle, adding water, wherein the solid-to-liquid ratio in the kettle is 1:4, starting stirring, adding sodium hydroxide into the kettle to adjust the pH value of feed liquid in the kettle to be more than or equal to 10, adding 1.23kg of hydrazine hydrate to carry out silver reduction, keeping the reaction temperature at 50 ℃, the reaction time at 1h, and setting the stirring speed at 300rmp to ensure uniform stirring.
(10) Silver electrolysis casting of silver ingot: and (3) filtering, washing and drying the reduced silver powder obtained in the step (9), casting a silver anode plate, then hanging the silver anode plate on a hook of an anode conducting rod of a silver electrolytic cell, sleeving an anode bag, taking a titanium plate as a cathode plate, starting an electrolyte circulating pump, adding silver nitrate electrolyte into the cell, starting a silver electrolytic rectifier, introducing direct current to start electrolytic refining, controlling the temperature of the electrolyte at 45 ℃, sending the electrolytic silver powder produced by the silver electrolytic refining to a melting furnace to cast into 1.10kg of silver ingots, wherein the obtained silver ingots are national standard silver with the purity of not less than 99.99%, and the silver recovery rate is 99.02%.
The elemental content of the gold ingot and the silver ingot obtained in comparative example 1 were analyzed, and the results are recorded in tables 3 and 4.
TABLE 3 gold ingot element content detection and analysis results
| Au％ | Ag％ | Pb％ | Cu％ |
| 99.9944 | 0.0027 | 0.0001 | 0.0006 |
| Fe％ | Pd％ | Sb％ | Bi％ |
| 0.0007 | 0.0011 | 0.0002 | 0.0002 |
TABLE 4 silver ingot element content detection and analysis results
| Ag％ | Pb％ | Sb％ | Cu％ |
| 99.9971 | 0.0002 | 0.0001 | 0.0007 |
| Fe％ | Pd％ | Bi％ | Te％ |
| 0.0009 | 0.0003 | 0.0004 | 0.0001 |
| Se％ | |||
| 0.0002 |
Comparative example 2
(1) Preparing a gold splashing sheet: weighing 45kg of crude gold material, smelting at 1150 ℃, and preparing a gold sheet with the thickness of 0.03-0.1 mm through a graphite crucible dripping sheet.
(2) Preparing a dilute hydrochloric acid solution: adding concentrated hydrochloric acid and water into a reaction kettle to prepare 225L of dilute hydrochloric acid solution, then starting stirring and heating to 65-80 ℃, wherein the hydrochloric acid content of the dilute hydrochloric acid solution is 180-230 g/L, and the stirring speed is set to be 200 rmp.
(3) Chlorination leaching: adding gold flakes into a 300L titanium reaction kettle, then adding 22kg of sodium chlorate for chlorination gold leaching, keeping the reaction temperature at 65-80 ℃, the reaction time at 1.5h, the adding speed of the sodium chlorate at 300g/min, and setting the stirring speed at 300 rmp.
(4) Chlorine removal: and (3) raising the temperature of the reaction kettle to 90 ℃, and performing chlorine removal for 15 min.
(5) Cooling and filtering: after chlorine removal is finished, cooling the reaction kettle, pouring the solution in the kettle into a high-precision pneumatic filtering vehicle for filtering, and respectively carrying out a gold reduction step and a silver reduction step on the filtrate and the filter residue.
(6) Primary gold reduction: adding the filtrate obtained in the step (5) into a primary gold reduction kettle, starting stirring and heating to 50 ℃, and then slowly introducing 14m3Sulfur dioxide gas (density 2.92 kg/m)3) The gold reduction was carried out as a reducing agent for a reaction time of 1.5 hours, the reduction end point potential was controlled to +665mv, and the stirring speed was set to 300 rmp.
(7) Gold smelting: filtering the primary reduced gold powder, washing a filter cake with hot water at 40-70 ℃, drying, feeding the filter cake into a melting furnace, casting into 38.6kg of gold ingot, and feeding the filtrate into a secondary gold reduction step, wherein the obtained gold ingot is national standard gold I with the purity of not less than 99.99%, and the gold recovery rate is 89.06%.
(8) And (3) secondary gold reduction: and (3) adding the filtrate obtained in the step (7) into a secondary gold reduction kettle, starting stirring and heating to 50 ℃, then introducing excessive sulfur dioxide gas as a reducing agent to carry out secondary gold reduction, wherein the reaction time is 0.5h, the reduction end point potential is controlled to be +338mv, reacting to obtain secondary reduced gold powder, washing and drying the secondary reduced gold powder, and returning to the step (1), wherein the excessive sulfur dioxide gas means introducing sulfur dioxide gas until no solid gold precipitate is generated in the solution.
(9) Silver reduction: weighing the dry weight of the silver chloride filter residue obtained in the step (5) to be 1.47kg, adding the silver chloride filter residue into a silver reduction kettle, adding water, wherein the solid-to-liquid ratio in the kettle is 1:4, starting stirring, adding sodium hydroxide into the kettle to adjust the pH value of feed liquid in the kettle to be more than or equal to 10, adding 1.23kg of hydrazine hydrate to carry out silver reduction, keeping the reaction temperature at 50 ℃, the reaction time at 1h, and setting the stirring speed at 300rmp to ensure uniform stirring.
(10) Silver electrolysis casting of silver ingot: and (3) filtering, washing and drying the reduced silver powder obtained in the step (9), casting a silver anode plate, then hanging the silver anode plate on a hook of an anode conducting rod of a silver electrolytic tank, sleeving an anode bag, taking a titanium plate as a cathode plate, starting an electrolyte circulating pump, adding silver nitrate electrolyte into the tank, starting a silver electrolytic rectifier, introducing direct current to start electrolytic refining, controlling the temperature of the electrolyte at 45 ℃, sending the electrolytic silver powder produced by the silver electrolytic refining to a melting furnace to cast into 1.107kg of silver ingots, wherein the obtained silver ingots are national standard silver with the purity of not less than 99.99%, and the silver recovery rate is 99.61%.
Elemental content detection analysis was performed on the gold ingot and silver ingot obtained in comparative example 2, and the results are recorded in tables 5 and 6.
TABLE 5 gold ingot element content detection and analysis results
| Au％ | Ag％ | Pb％ | Cu％ |
| 99.9957 | 0.0014 | 0.0001 | 0.0007 |
| Fe％ | Pd％ | Sb％ | Bi％ |
| 0.0007 | 0.0012 | 0.0001 | 0.0001 |
TABLE 6 silver ingot element content detection and analysis results
| Ag％ | Pb％ | Sb％ | Cu％ |
| 99.9981 | 0.0001 | 0.0001 | 0.0004 |
| Fe％ | Pd％ | Bi％ | Te％ |
| 0.0007 | 0.0001 | 0.0002 | 0.0002 |
| Se％ | |||
| 0.0001 |
Comparative example 3
(1) Preparing a gold splashing sheet: weighing 45kg of crude gold material, smelting at 1150 ℃, and preparing a gold sheet with the thickness of 0.03-0.1 mm through a graphite crucible dripping sheet.
(2) Preparing a dilute hydrochloric acid solution: adding concentrated hydrochloric acid and water into a reaction kettle to prepare 225L of dilute hydrochloric acid solution, then starting stirring and heating to 65-80 ℃, wherein the hydrochloric acid content of the dilute hydrochloric acid solution is 180-230 g/L, and the stirring speed is set to be 200 rmp.
(3) Chlorination leaching: adding gold flakes into a 300L titanium reaction kettle, then adding 22kg of sodium chlorate for chlorination gold leaching, keeping the reaction temperature at 65-80 ℃, the reaction time at 1.5h, the adding speed of the sodium chlorate at 300g/min, and setting the stirring speed at 300 rmp.
(4) Chlorine removal: and (3) raising the temperature of the reaction kettle to 90 ℃, and performing chlorine removal for 15 min.
(5) Cooling and filtering: after chlorine removal is finished, cooling the reaction kettle, pouring the solution in the kettle into a high-precision pneumatic filtering vehicle for filtering, and respectively carrying out a gold reduction step and a silver reduction step on the filtrate and the filter residue.
(6) Primary gold reduction: and (3) adding the filtrate obtained in the step (5) into a primary reduction kettle, starting stirring and heating to 50 ℃, then slowly adding 41kg of hydroxylamine hydrochloride serving as a reducing agent in batches for primary gold reduction, wherein the reaction time is 1.5h, the reduction end point potential is controlled to be +665mv, and the stirring speed is set to be 300 rmp.
(7) Gold smelting: filtering the primary reduced gold powder, washing a filter cake with hot water at 40-70 ℃, drying, feeding the filter cake into a melting furnace, casting into a gold ingot of 43.1kg, and feeding the filtrate into a secondary gold reduction step, wherein the obtained gold ingot is national standard gold with the purity of not less than 99.99%, and the gold recovery rate is 99.45%.
(8) And (3) secondary gold reduction: and (3) adding the filtrate obtained in the step (7) into a secondary gold reduction kettle, starting stirring and heating to 50 ℃, then adding excessive hydroxylamine hydrochloride as a reducing agent to carry out secondary gold reduction, wherein the reaction time is 0.5h, the reduction end point potential is controlled to be +338mv, reacting to obtain secondary reduced gold powder, washing and drying the secondary reduced gold powder, and returning to the step (1), wherein the excessive hydroxylamine hydrochloride means adding hydroxylamine hydrochloride until no solid gold precipitate is generated in the solution.
(9) Silver reduction: weighing the dry weight of the silver chloride filter residue obtained in the step (5) to be 1.47kg, adding the silver chloride filter residue into a silver reduction kettle, adding water, wherein the solid-to-liquid ratio in the kettle is 1:4, starting stirring, adding concentrated hydrochloric acid into the kettle to adjust the pH value of a feed liquid in the kettle to be 1-2, adding 1.23kg of iron powder to perform silver replacement to obtain the reduced silver powder, keeping the reaction temperature at 50 ℃, the reaction time at 1h, setting the stirring speed at 300rmp, and ensuring uniform stirring.
(10) Silver electrolysis casting of silver ingot: filtering, washing and drying the reduced silver powder obtained by replacement in the step (9), casting a silver anode plate, then hanging the silver anode plate on a hook of an anode conducting rod of a silver electrolytic cell, sleeving an anode bag, taking a titanium plate as a cathode plate, starting an electrolyte circulating pump, adding silver nitrate electrolyte into the cell, starting a silver electrolytic rectifier, introducing direct current to start electrolytic refining, controlling the temperature of the electrolyte at 45 ℃, sending the electrolytic silver powder produced by the silver electrolytic refining to a melting furnace to cast into 0.983kg of silver ingots, wherein the obtained silver ingots are national standard first silver with the purity of not less than 99.99%, and the silver recovery rate is 88.41%.
Elemental content detection analysis was performed on the gold ingot and silver ingot obtained in comparative example 3, and the results are recorded in tables 7 and 8.
TABLE 7 gold ingot element content detection and analysis results
| Au％ | Ag％ | Pb％ | Cu％ |
| 99.9969 | 0.0013 | 0.0001 | 0.0003 |
| Fe％ | Pd％ | Sb％ | Bi％ |
| 0.0004 | 0.0008 | 0.0001 | 0.0001 |
TABLE 8 silver ingot element content detection and analysis results
| Ag％ | Pb％ | Sb％ | Cu％ |
| 99.9965 | 0.0002 | 0.0001 | 0.0008 |
| Fe％ | Pd％ | Bi％ | Te％ |
| 0.0018 | 0.0003 | 0.0001 | 0.0001 |
| Se％ | |||
| 0.0001 |
Compared with the traditional gold and silver refining process, the method has the advantages that the silver in the filter residue is efficiently recovered and purified while gold and silver are efficiently refined, the gold and silver purity obtained by refining is high, the recovery rate is excellent, the product quality is stable, the process is simple, the operation is convenient, and the economic value and the practical value are higher.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (6)
1. A method for refining gold and silver is characterized by comprising the following steps:
(1) preparing a gold splashing sheet: smelting the crude gold and gold material at 1150 ℃ to prepare gold sheets with the thickness of 0.03-0.1 mm;
(2) preparing a dilute hydrochloric acid solution: adding concentrated hydrochloric acid and water into a reaction kettle to prepare a dilute hydrochloric acid solution, then starting stirring and heating to 65-80 ℃, wherein the hydrochloric acid content of the dilute hydrochloric acid solution is 180-230 g/L;
(3) chlorination leaching: adding gold flakes into a reaction kettle, then adding an oxidant for chlorination gold leaching, keeping the reaction temperature at 65-80 ℃, and reacting for 1-2 h, wherein the oxidant adding speed is 300-500 g/min, and the mass ratio of the oxidant to the gold flakes is 0.4-0.5: 1;
(4) chlorine removal: raising the temperature of the reaction kettle to be more than 85 ℃, and performing chlorine removal for 10-20 min;
(5) cooling and filtering: after chlorine removal is finished, cooling the reaction kettle, pouring the solution in the kettle into a high-precision pneumatic filter vehicle for filtering, and respectively carrying out a primary gold reduction step and a silver reduction step on the filtrate and filter residue;
(6) primary gold reduction: adding the filtrate obtained in the step (5) into a primary gold reduction kettle, starting stirring and heating to 50-60 ℃, then slowly adding hydroxylamine hydrochloride in batches as a reducing agent to carry out primary gold reduction, wherein the reaction time is 1-2 h, the mass ratio of the consumption of the hydroxylamine hydrochloride to gold flakes is 0.8-1: 1, and the reduction end point potential is controlled to be not less than +650 mv;
(7) gold smelting: filtering the primary reduced gold powder, washing a filter cake with hot water at 40-70 ℃, drying, feeding the filter cake into a melting furnace, casting into a gold ingot, and feeding the filtrate into a secondary gold reduction step;
(8) and (3) secondary gold reduction: adding the filtrate obtained in the step (7) into a secondary gold reduction kettle, starting stirring and heating to 50-60 ℃, then adding excessive hydroxylamine hydrochloride as a reducing agent to carry out secondary gold reduction, wherein the reaction time is 0.5-1 h, the reduction end point potential is controlled to be not higher than +340mv, reacting to obtain secondary reduced gold powder, washing and drying the secondary reduced gold powder, and returning to the step (1);
(9) silver reduction: weighing the filter residue obtained in the step (5), adding the weighed filter residue into a silver reduction kettle, adding water, wherein the solid-to-liquid ratio in the kettle is 1: 4-6, starting stirring, adding an alkaline substance into the kettle to adjust the pH value of feed liquid in the kettle to be more than or equal to 10, then adding hydrazine hydrate to carry out silver reduction, keeping the reaction temperature at 30-50 ℃, reacting for 1-1.5 h, and the mass ratio of the hydrazine hydrate amount to the filter residue is 0.8-1: 1;
(10) silver electrolysis casting of silver ingot: and (3) filtering, washing and drying the reduced silver powder obtained in the step (9), casting a silver anode plate, then hanging the silver anode plate on a hook of an anode conducting rod of a silver electrolytic cell, sleeving an anode bag, taking a titanium plate as a cathode plate, starting an electrolyte circulating pump, adding silver nitrate electrolyte into the cell, starting a silver electrolytic rectifier, introducing direct current to start electrolytic refining, controlling the temperature of the electrolyte at 30-45 ℃, feeding the electrolytic silver powder obtained through the silver electrolytic refining to a melting furnace, and casting the electrolytic silver powder into silver ingots.
2. The method for refining gold and silver according to claim 1, wherein the crude gold and gold material comprises jewelry gold, industrial gold, alloy gold and mineral gold with the grade of 70-99.95%.
3. A gold and silver refining method as claimed in claim 1, wherein in the chlorination leaching process of step (3), the oxidant is sodium chlorate.
4. A gold and silver refining method as claimed in claim 1, wherein in the gold casting process in step (7), the gold recovery rate is up to 99.97%, and the gold ingot obtained by casting is a standard gold ingot with the purity not lower than 99.99%.
5. A method for refining gold and silver as recited in claim 1, wherein in the step (9) of silver reduction, the alkaline substance is sodium hydroxide or potassium hydroxide.
6. A refining method of gold and silver as recited in claim 1, characterized in that, in the step (10) of electrolytic refining, the recovery rate of silver reaches 99.88%, and the obtained silver ingot is standard silver ingot with purity not lower than 99.99%.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102274978A (en) * | 2011-08-26 | 2011-12-14 | 山东黄金矿业(莱州)有限公司三山岛金矿 | Method for quickly wet-process refining non-standard coarse gold powder |
| CN102560137A (en) * | 2011-12-28 | 2012-07-11 | 河南中原黄金冶炼厂有限责任公司 | Refining process of alloyed gold |
| CN109023433A (en) * | 2018-09-04 | 2018-12-18 | 安阳市岷山有色金属有限责任公司 | A kind of thick electrorefining of silver technique |
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