CN110567838A - Method for detecting gold content in gold-plated part - Google Patents
Method for detecting gold content in gold-plated part Download PDFInfo
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- CN110567838A CN110567838A CN201910932352.3A CN201910932352A CN110567838A CN 110567838 A CN110567838 A CN 110567838A CN 201910932352 A CN201910932352 A CN 201910932352A CN 110567838 A CN110567838 A CN 110567838A
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 title claims abstract description 186
- 239000010931 gold Substances 0.000 title claims abstract description 186
- 229910052737 gold Inorganic materials 0.000 title claims abstract description 184
- 238000000034 method Methods 0.000 title claims abstract description 43
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 48
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 48
- 239000000243 solution Substances 0.000 claims description 79
- 229910045601 alloy Inorganic materials 0.000 claims description 54
- 239000000956 alloy Substances 0.000 claims description 54
- 238000001816 cooling Methods 0.000 claims description 42
- 238000010438 heat treatment Methods 0.000 claims description 42
- 239000002245 particle Substances 0.000 claims description 40
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 38
- 239000007788 liquid Substances 0.000 claims description 34
- 239000002244 precipitate Substances 0.000 claims description 26
- 229910052709 silver Inorganic materials 0.000 claims description 23
- 239000004332 silver Substances 0.000 claims description 23
- 238000003723 Smelting Methods 0.000 claims description 21
- 238000000926 separation method Methods 0.000 claims description 21
- 239000000203 mixture Substances 0.000 claims description 20
- 238000007664 blowing Methods 0.000 claims description 17
- 238000009835 boiling Methods 0.000 claims description 17
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 16
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 16
- 229910021538 borax Inorganic materials 0.000 claims description 16
- 238000001704 evaporation Methods 0.000 claims description 16
- 239000004328 sodium tetraborate Substances 0.000 claims description 16
- 235000010339 sodium tetraborate Nutrition 0.000 claims description 16
- UQGFMSUEHSUPRD-UHFFFAOYSA-N disodium;3,7-dioxido-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane Chemical compound [Na+].[Na+].O1B([O-])OB2OB([O-])OB1O2 UQGFMSUEHSUPRD-UHFFFAOYSA-N 0.000 claims description 15
- 229910000464 lead oxide Inorganic materials 0.000 claims description 13
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 claims description 13
- 238000004321 preservation Methods 0.000 claims description 12
- 229910021642 ultra pure water Inorganic materials 0.000 claims description 12
- 239000012498 ultrapure water Substances 0.000 claims description 12
- 238000001035 drying Methods 0.000 claims description 10
- 238000001914 filtration Methods 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 9
- 238000004380 ashing Methods 0.000 claims description 8
- 235000013312 flour Nutrition 0.000 claims description 8
- 239000002893 slag Substances 0.000 claims description 8
- 238000003756 stirring Methods 0.000 claims description 8
- 238000005303 weighing Methods 0.000 claims description 8
- 238000000137 annealing Methods 0.000 claims description 7
- 239000011259 mixed solution Substances 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- 241000416536 Euproctis pseudoconspersa Species 0.000 claims description 5
- 239000000706 filtrate Substances 0.000 claims description 5
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 claims description 4
- 238000010304 firing Methods 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 3
- 229910001316 Ag alloy Inorganic materials 0.000 claims description 2
- 229910001020 Au alloy Inorganic materials 0.000 claims description 2
- 238000009423 ventilation Methods 0.000 claims description 2
- 238000001514 detection method Methods 0.000 abstract description 16
- 238000012360 testing method Methods 0.000 abstract description 9
- 229910001092 metal group alloy Inorganic materials 0.000 abstract description 4
- 238000009826 distribution Methods 0.000 abstract description 3
- 239000003870 refractory metal Substances 0.000 abstract description 3
- 235000013339 cereals Nutrition 0.000 description 18
- 238000007747 plating Methods 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 8
- 229910021607 Silver chloride Inorganic materials 0.000 description 6
- 230000008020 evaporation Effects 0.000 description 6
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 6
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 230000001680 brushing effect Effects 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000008187 granular material Substances 0.000 description 3
- 238000000227 grinding Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 2
- 235000011130 ammonium sulphate Nutrition 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- IYRDVAUFQZOLSB-UHFFFAOYSA-N copper iron Chemical compound [Fe].[Cu] IYRDVAUFQZOLSB-UHFFFAOYSA-N 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/34—Purifying; Cleaning
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N5/00—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid
- G01N5/04—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder
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- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Molecular Biology (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
Abstract
The invention relates to a method for detecting gold content in gold-plated parts, which comprises the steps of firstly stripping gold from the gold-plated parts by nitric acid to obtain a gold-plated layer and a gold stripping solution, treating the gold-plated layer by a small gold testing method, and detecting to obtain the gold content M1concentrating the gold stripping solution, treating by a small gold testing method, and detecting to obtain the gold content M2，M1And M2The sum of the mass of (a) is the gold content in the gold-plated part. The method is not only suitable for analyzing large samples of gold-plated parts with complex diversity and uneven gold distribution, but also suitable for analyzing gold-plated parts of refractory metal alloy, and has high accuracy and representativeness of detection results, and the difference of the detection results of parallel groups is 5 percentwithin.
Description
Technical Field
The invention belongs to the technical field of chemical detection, and particularly relates to a method for detecting gold content in a gold-plated part.
background
with the rapid development of the information age, the production of electronic component products is increasing. The weight of gold plating process, which is the core process technology of electronic components, is more and more emphasized. The quality of gold plating is directly related to the quality guarantee of electronic products, and the reliability and stability of the products are directly influenced. The difficulty and workload of the inspection are increased, and higher requirements are put on the inspection requirements.
The existing gold-plated parts, such as gold-plated copper substrate and gold-plated iron substrate, have many kinds, the single gold-plated part has a large head, the weight is heavy, and the sample preparation is difficult, the fire test method in the prior art has an unsatisfactory test effect on a large sample, and the detection result has poor representativeness. This is because too high a copper iron tends to produce a microscopic "matte effect" and the melting time required is greatly increased when the gold-plated piece is larger. For the gold plating of a nickel substrate, which belongs to a refractory metal alloy gold-plated piece, the analysis effect of the fire gold testing method in the prior art is not ideal. When the content of nickel is too high, the melting point of slag becomes high, so that granular lead is generated to influence the test result; and when the copper and nickel content is too high, the copper and nickel are easily captured by lead and enter a lead block, so that the influence on subsequent ash blowing is caused.
disclosure of Invention
in order to solve the problems in the prior art, the invention provides a method for detecting the gold content in a gold-plated part. The method provided by the invention is not only suitable for analyzing large samples of complex and various gold-plated parts with non-uniform gold distribution, but also suitable for analyzing refractory metal alloy gold-plated parts, and has high detection result accuracy and representativeness, and the difference of parallel group detection results is within 5%.
The technical scheme adopted by the invention is as follows:
A method for detecting gold content in gold-plated parts comprises the following steps:
(1) Immersing the gold-plated piece into a nitric acid solution, heating until the gold-plated layer is completely stripped, removing the gold-plated piece substrate, filtering the liquid while the liquid is hot, filtering the gold-plated layer on filter paper, and collecting filtrate as a gold stripping solution;
(2) Drying the filter paper with the gold-plated layer, ashing and cooling to obtain an ashed sample;
(3) Adding a mixture of lead oxide and flour into the ashed sample obtained in the step (2), uniformly stirring, adding electrolytic lead and silver powder, covering a layer of mixture of anhydrous sodium carbonate and borax, smelting, cooling and removing slag to obtain a lead button;
(4) ventilating and blowing ash to the lead button in the step (3), and when a color film appears on the surface of the lead button, carrying out heat preservation under a closed condition and then cooling to obtain gold and silver combined particles;
(5) annealing and cooling the gold and silver alloy particles, and forming into an alloy coil;
(6) And (3) carrying out gold separation treatment on the alloy roll by using nitric acid, which specifically comprises the following steps: adding preheated dilute nitric acid into the alloy coil, continuously heating until the alloy coil is completely dissolved, standing for layering, pouring the upper-layer gold layering solution into the gold stripping solution in the step (1), and adding preheated concentrated nitric acid into the lower-layer precipitate; after continuing heating, standing and layering, pouring the upper layer of gold layering liquid into the gold stripping liquid in the step (1), and adding preheated concentrated nitric acid into the lower layer of precipitate; after continuing heating, standing and layering, pouring the upper layer of gold-separating liquid into the gold-stripping liquid in the step (1), and washing the lower layer of precipitate by using boiling ultrapure water to obtain gold after gold separation;
(7) drying the gold subjected to gold separation in the step (6), then firing, cooling, weighing, and recording as M1；
(8) heating and concentrating the mixed solution of the gold stripping solution and the gold separating solution in the step (6) to obtain a concentrated solution; then transferring the concentrated solution into a container containing electrolytic lead, lead oxide and silver powder, evaporating to dryness, then continuously smelting, cooling and deslagging to obtain alloy particles;
(9) carrying out ventilation and ash blowing on the alloy particles obtained in the step (8), and when a color film appears on the surface of the alloy particles, carrying out heat preservation and cooling under a closed condition to obtain ash-blown alloy particles;
(10) Adding nitric acid solution into the alloy particles after ash blowing, heating until the alloy particles are completely dissolved, and addingHydrochloric acid to generate precipitate, removing the precipitate, adding boiling ultrapure water into the alloy particle system, boiling, cooling, and detecting the gold content to obtain M2；
(11)M1And M2The sum of the masses of (a) and (b) is the gold content in the gold-plated piece.
wherein, the smelting, ash blowing and gold separating operations in the steps (3) to (6) are called as a small-scale gold test treatment process.
In the step (1), the concentration of the nitric acid is 4.8-5.07 mol/L;
The heating temperature is 180-220 deg.C, and the heating time is 5-8 h.
in the step (2), the ashing temperature is 400-500 ℃, and the ashing time is 0.5-1.5 h.
In the step (3), the mass ratio of the lead oxide to the flour is 8:1-12: 1;
the mass ratio of the silver powder to the ashed sample is 3:1-5: 1.
In the step (3), the temperature for carrying out the smelting is 850-950 ℃, and the time for carrying out the smelting is 15-25 min.
In the step (4), the ash blowing time is 85-95 min;
The temperature of the heat preservation is 850-950 ℃, and the time of the heat preservation is 2-8 min.
In the step (5), annealing treatment is carried out for 5-15min at 700-800 ℃.
In the step (6), the concentration of the dilute nitric acid is 4.8-5.07mol/L, and the temperature of the preheated dilute nitric acid is 85-95 ℃;
The concentration of the concentrated nitric acid is 9.60-10.13mol/L, and the temperature of the preheated concentrated nitric acid is 85-95 ℃.
In the step (6), after adding nitric acid each time, the heating temperature is 85-95 ℃, and the heating time is 20-40 min.
Washing the lower layer precipitate with boiling ultrapure water for 4-6 times.
In the step (7), the temperature for burning is 750-850 ℃, and the time for burning is 2-8 min.
In the step (8), the temperature for performing the heating concentration is 180-220 ℃.
in the step (8), the mass ratio of the silver powder to the ashed sample is 3:1-5:1, and the mass ratio of the anhydrous sodium carbonate to the borax is 1:1-3: 1;
The temperature for heating and evaporating to dryness is 280-320 ℃.
in the step (8), when the concentrated solution is heated and evaporated to dryness, a small amount of mixture of anhydrous sodium carbonate and borax is covered on the concentrated solution to prevent the liquid from splashing in the evaporation and dryness process.
In the step (8), before smelting, covering a layer of mixture of anhydrous sodium carbonate and borax on the material;
The temperature for carrying out the smelting is 850-950 ℃, and the time for carrying out the smelting is 15-25 min.
In the step (9), the ash blowing time is 85-95 min;
The temperature of the heat preservation is 850-950 ℃, and the time of the heat preservation is 2-8 min.
In the step (10), the concentration of the nitric acid is 2.4-2.53 wt%;
The heating temperature is 180-220 ℃, and the heating time is 5-8 h;
Detecting the gold content by adopting AAS, which comprises the following steps: adding hydrochloric acid into alloy particle system after boiling with ultrapure water, fixing volume to V (L), shaking, detecting concentration to C (mg/L) by AAS, and determining gold content M2is C V (mg).
The invention has the beneficial effects that:
The method for detecting the gold content in the gold-plated part comprises the steps of firstly stripping gold from the gold-plated part by nitric acid to obtain a gold-plated layer and a gold stripping solution, and detecting the gold content M of the gold-plated layer after the gold-plated layer is treated by a small gold testing method1concentrating the gold stripping solution, treating by a small gold testing method, and detecting to obtain the gold content M2，M1and M2the sum of the mass of (a) is the gold content in the gold-plated part. The method of the invention is not only suitable for analyzing large samples of gold-plated parts with complex and various shapes and uneven gold distribution, but also suitable for analyzing difficult-to-distribute gold-plated partsanalyzing the molten metal alloy gold-plated piece; the gold plating layer on the gold plating piece substrate is stripped by nitric acid, and then the subsequent gold content is detected, but the existing fire gold testing method needs to dissolve the whole gold plating piece (comprising the gold plating piece substrate and the gold plating layer). In conclusion, the method has high detection result accuracy and is representative, the detection result difference of the parallel group is within 5%, and the detection result difference with the delivery result of the authority is not more than 5%.
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, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic flow chart of the method for detecting the gold content in gold-plated parts according to the invention.
Detailed Description
in order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
Example 1
The present embodiment provides a method for detecting gold content in gold-plated parts, and a flowchart is shown in fig. 1, and includes the following steps:
(1) weighing gold-plated part M041.06g, immersion concentrationHeating the gold plated piece for 8 hours at 180 ℃ in 4.8mol/L nitric acid solution until the gold plating layer of the gold plated piece is completely stripped, removing the gold plated piece substrate, filtering the liquid while the liquid is hot, filtering the gold plating layer on filter paper, and collecting filtrate as gold stripping liquid;
(2) Drying the filter paper with the gold-plated layer, ashing for 1h at 450 ℃, and cooling to obtain an ashed sample;
(3) Transferring 0.15g of the ashed sample obtained in the step (2) into a crucible, adding 20g of a mixture consisting of lead oxide and flour according to a mass ratio of 10:1, uniformly stirring, adding 30g of electrolytic lead and 600mg of silver powder, covering a layer of mixture consisting of anhydrous sodium carbonate and borax according to a mass ratio of 2:1, then smelting in a muffle furnace at 900 ℃ for 20min, and cooling to remove slag to obtain a lead button;
(4) placing the lead button in the step (3) in a preheated cupel (preheated at 920 ℃ for 20min), slightly opening a furnace door to ventilate ash for 90min, closing the furnace door when a color film appears on the surface of the lead button, preserving heat at 900 ℃ for 5min in a closed environment, taking out and cooling to obtain gold and silver combined particles;
(5) knocking the two sides of the gold and silver combined grains by a hand hammer to enable the gold and silver combined grains to be oblate, brushing off bottom attachments, knocking the gold and silver combined grains to be about 2mm thick, putting the gold and silver combined grains into a cupel, annealing for 10min at 750 ℃, taking out the gold and silver combined grains for cooling, grinding the gold and silver combined grains into thin sheets with the thickness of 0.15 +/-0.02 mm, and rolling the thin sheets into hollow rolls to obtain alloy rolls;
(6) And (3) carrying out gold separation treatment on the alloy roll by adopting a nitric acid solution, which specifically comprises the following steps: adding 20ml of 4.8mol/L dilute nitric acid solution preheated to 90 ℃ into the alloy coil, and heating for 30min until the alloy coil is completely dissolved; after standing and layering, pouring the upper layer gold-layering solution into the gold-stripping solution in the step (1), adding 30ml of 9.60mol/L concentrated nitric acid solution preheated to 90 ℃ into the lower layer precipitate, and continuing to heat for 30 min; after standing and layering, pouring the upper layer of gold layering liquid into the gold stripping liquid, then adding 30ml of 9.60mol/L concentrated nitric acid solution preheated to 90 ℃ into the lower layer of precipitate, continuing to heat for 30min, after standing and layering, pouring the upper layer of gold layering liquid into the gold stripping liquid, and washing the lower layer of precipitate for 5 times by adopting boiling ultrapure water to obtain gold after gold layering, namely finishing three times of gold layering operation;
(7) Transferring the gold subjected to gold separation in the step (6) into a 50ml crucible for drying, then firing in a muffle furnace at 800 ℃ for 5min, taking out, cooling, weighing, and measuring M1130.26 mg;
(8) concentrating the mixed solution of the gold stripping solution and the gold separating solution in the step (6) to 30ml under the heating condition of 200 ℃ to obtain a concentrated solution; then, transferring 30ml of the concentrated solution into a container containing 30g of electrolytic lead, 10g of lead oxide and 8mg of silver powder, heating and evaporating to dryness at 280 ℃ (when heating and evaporating to dryness, covering a little of mixture consisting of anhydrous sodium carbonate and borax according to the mass ratio of 2:1 on the concentrated solution to prevent liquid from splashing in the evaporation and evaporation process), slightly cooling, covering a layer of mixture consisting of anhydrous sodium carbonate and borax according to the mass ratio of 2:1 on the material, then smelting at 900 ℃ for 20min, and cooling and removing slag to obtain alloy particles;
(9) Placing the alloy particles obtained in the step (8) in a preheated cupel (preheated at 920 ℃ for 20min), slightly opening a furnace door to ventilate ash for 90min, closing the furnace door when color films appear on the surfaces of the alloy particles, preserving heat at 900 ℃ for 5min in a closed environment, taking out and cooling to obtain ash-blown alloy particles;
(10) adding a nitric acid solution with the concentration of 2.4mol/L into the alloy particles after the ash blowing, heating to 200 ℃, adding 5ml of hydrochloric acid after the alloy particles are completely dissolved, and generating silver chloride precipitate under the stirring condition; removing silver chloride precipitate, adding 20ml boiling ultrapure water into the alloy granule system, boiling until the upper layer liquid is clear, cooling to room temperature, and detecting gold content and recording as M2(ii) a Adding until the concentration of hydrochloric acid is 10 wt%, and the volume is constant V (L), shaking up, and detecting the gold content C (mg/L) in the lower layer material by adopting AAS (anaerobic ammonium sulfate), namely the gold content M in the gold stripping solution2(C x V) 0.82 mg;
(11)M1and M2The sum of the masses of (A) and (B) is 131.08mg, namely the content of gold in the gold-plated part is (M)1+M2)/M0＝3192g/t。
example 2
The embodiment provides a method for detecting gold content in a gold-plated part, which comprises the following steps:
(1) weighing gold-plated part M043.11g in weight portionadding into 5.07mol/L nitric acid solution, heating at 220 deg.C for 5 hr until the gold-plating layer of the gold-plated piece is completely stripped, removing the gold-plated piece matrix, filtering the liquid while it is hot, filtering the gold-plating layer onto filter paper, and collecting the filtrate as gold stripping liquid;
(2) drying the filter paper with the gold-plated layer, ashing for 1.5h at 400 ℃, and cooling to obtain an ashed sample;
(3) Transferring 0.14g of the ashed sample obtained in the step (2) into a crucible, adding a mixture consisting of 20g of lead oxide and flour according to a mass ratio of 8:1, uniformly stirring, adding 30g of electrolytic lead and 600mg of silver powder, covering a layer of mixture consisting of anhydrous sodium carbonate and borax according to a mass ratio of 2:1, then smelting in a muffle furnace at 850 ℃ for 25min, and cooling to remove slag to obtain a lead button;
(4) placing the lead button in the step (3) in a preheated cupel (preheated at 900 ℃ for 30min), slightly opening a furnace door to ventilate ash for 85min, closing the furnace door when a color film appears on the surface of the lead button, preserving heat at 850 ℃ for 8min in a closed environment, taking out and cooling to obtain gold and silver combined particles;
(5) Knocking the two sides of the gold and silver combined grains by a hand hammer to enable the gold and silver combined grains to be oblate, brushing off bottom attachments, knocking the gold and silver combined grains to be about 2mm thick, putting the gold and silver combined grains into a cupel for annealing treatment at 700 ℃ for 15min, taking out the gold and silver combined grains for cooling, grinding the gold and silver combined grains into a sheet with the thickness of 0.13mm, and rolling the sheet into a hollow roll to obtain a gold roll;
(6) And (3) carrying out gold separation treatment on the alloy roll by adopting a nitric acid solution, which specifically comprises the following steps: adding 20ml of dilute nitric acid solution of 5.07mol/L preheated to 85 ℃ into the alloy coil, heating for 20min until the alloy coil is completely dissolved, standing and layering, pouring the upper-layer gold-layering solution into the gold stripping solution in the step (1), adding 30ml of concentrated nitric acid solution of 10.13mol/L preheated to 85 ℃ into the lower-layer precipitate, and continuing heating for 20 min; after standing and layering, pouring the upper layer of gold layering liquid into the gold stripping liquid, then adding 30ml of 10.13mol/L concentrated nitric acid solution preheated to 85 ℃ into the lower layer of precipitate, continuing to heat for 20min, after standing and layering, pouring the upper layer of gold layering liquid into the gold stripping liquid, and washing the lower layer of precipitate for 4 times by adopting boiling ultrapure water to obtain gold after gold layering, namely finishing three times of gold layering operation;
(7) transferring the gold subjected to gold separation in the step (6) into a 50ml crucible for drying, then burning in a muffle furnace at 750 ℃ for 8min, taking out, cooling, weighing, and measuring M1130.98 mg;
(8) Concentrating the mixed solution of the gold stripping solution and the gold separating solution in the step (6) to 30ml under the heating condition of 180 ℃ to obtain a concentrated solution; then, the concentrated solution is moved into a container containing 30g of electrolytic lead, 10g of lead oxide and 12mg of silver powder, heating and evaporating are carried out at 280 ℃ to dryness (when heating and evaporating are carried out, a small amount of mixture consisting of anhydrous sodium carbonate and borax according to the mass ratio of 2:1 is firstly covered on the concentrated solution to prevent liquid from splashing in the evaporation process), after the concentrated solution is slightly cooled, a layer of mixture of anhydrous sodium carbonate and borax is covered on the material, then smelting is carried out at 850 ℃ for 25min, and cooling and deslagging are carried out to obtain alloy particles;
(9) Placing the alloy particles obtained in the step (8) in a preheated cupel (preheated at 900 ℃ for 30min), slightly opening a furnace door to ventilate ash for 85min, closing the furnace door when a color film appears on the surface of the alloy particles, preserving heat at 850 ℃ for 8min in a closed environment, taking out and cooling to obtain ash-blown alloy particles;
(10) adding a nitric acid solution with the concentration of 2.53mol/L into the alloy particles after the ash blowing, heating to 180 ℃, adding 5ml of hydrochloric acid after the alloy particles are completely dissolved, and generating silver chloride precipitate under the stirring condition; removing silver chloride precipitate, adding 20ml boiling ultrapure water into the alloy granule system, boiling until the upper layer liquid is clear, cooling to room temperature, and detecting gold content and recording as M2(ii) a Adding hydrochloric acid with concentration of 10 wt%, fixing volume of V (L), shaking, and detecting gold content C (mg/L) in the lower layer material by AAS, i.e. gold content M in the gold stripping solution2(C x V) 0.66 mg;
(11)M1and M2131.64mg, i.e. the content of gold in the gold-plated part is (M)1+M2)/M0＝3054g/t。
Example 3
The embodiment provides a method for detecting gold content in a gold-plated part, which comprises the following steps:
(1) weighing gold-plated part M042.28g, the solution was immersed in a nitric acid solution having a concentration of 4.9mol/LHeating the gold-plated piece in the solution at 200 ℃ for 8h until the gold-plated layer of the gold-plated piece is completely stripped, removing the gold-plated piece substrate, filtering the solution while the solution is hot, filtering the gold-plated layer on filter paper, and collecting filtrate as gold stripping solution;
(2) Drying the filter paper with the gold-plated layer, ashing for 0.5h at 500 ℃, and cooling to obtain an ashed sample;
(3) transferring 0.18g of the ashed sample obtained in the step (2) into a crucible, adding a mixture consisting of 20g of lead oxide and flour according to the mass ratio of 12:1, uniformly stirring, adding 30g of electrolytic lead and 200mg of silver powder, covering a layer of mixture consisting of anhydrous sodium carbonate and borax according to the mass ratio of 3:1, smelting in a muffle furnace at 950 ℃ for 15min, and cooling to remove slag to obtain a lead button;
(4) Placing the lead button in the step (3) in a preheated cupel (preheated at 940 ℃ for 10min), slightly opening a furnace door to ventilate ash for 95min, closing the furnace door when a color film appears on the surface of the lead button, preserving heat at 950 ℃ for 2min in a closed environment, taking out and cooling to obtain gold and silver combined particles;
(5) knocking the two sides of the gold and silver combined grains by a hand hammer to enable the gold and silver combined grains to be oblate, brushing off bottom attachments, knocking the gold and silver combined grains to be about 2mm in thickness, putting the gold and silver combined grains into a cupel for annealing treatment at 800 ℃ for 5min, taking out the gold and silver combined grains for cooling, grinding the gold and silver combined grains into a sheet with the thickness of 0.17mm, and rolling the sheet into a hollow roll to obtain a gold roll;
(6) And (3) carrying out gold separation treatment on the alloy roll by adopting a nitric acid solution, which specifically comprises the following steps: adding 20ml of 4.9mol/L dilute nitric acid solution preheated to 95 ℃ into the alloy roll, heating for 40min until the alloy roll is completely dissolved, standing for layering, pouring the upper layer of gold separation solution into the gold stripping solution in the step (1), adding 9.8mol/L concentrated nitric acid solution preheated to 95 ℃ into the lower layer of precipitate, continuing to heat for 40min, standing for layering, pouring the upper layer of gold separation solution into the gold stripping solution, adding 30ml of 9.8mol/L concentrated nitric acid solution preheated to 95 ℃ into the lower layer of precipitate, continuing to heat for 40min, standing for layering, pouring the upper layer of gold separation solution into the gold stripping solution, washing the lower layer of precipitate for 6 times by using boiling ultrapure water, obtaining gold after gold separation, and finishing three times of gold separation operation;
(7) will be described in detail(6) Transferring the gold into a 50ml crucible for drying after gold separation, then burning in a muffle furnace at 850 ℃ for 2min, taking out, cooling, weighing, and measuring M1128.01 mg;
(8) Concentrating the mixed solution of the gold stripping solution and the gold separating solution in the step (6) to 30ml under the heating condition of 220 ℃ to obtain a concentrated solution; then, transferring 30ml of the concentrated solution into a container containing 30g of electrolytic lead, 10g of lead oxide and 600mg of silver powder, heating and evaporating to dryness at 320 ℃ (when heating and evaporating to dryness, a small amount of mixture of anhydrous sodium carbonate and borax is firstly covered on the concentrated solution to prevent liquid from splashing in the evaporation and evaporation process), slightly cooling, covering a layer of mixture of anhydrous sodium carbonate and borax according to the mass ratio of 2:1 on the material, then smelting at 950 ℃ for 15min, and cooling and removing slag to obtain alloy particles;
(9) Placing the alloy particles obtained in the step (8) in a cupel which is preheated (at 940 ℃ for 10min), slightly opening a furnace door to ventilate ash for 95min, closing the furnace door when color films appear on the surfaces of the alloy particles, preserving heat for 2min at 950 ℃ in a closed environment, taking out and cooling to obtain ash-blown alloy particles;
(10) adding a nitric acid solution with the concentration of 2.5mol/L into the alloy particles after the ash blowing, heating to 220 ℃, adding 5ml of hydrochloric acid after the alloy particles are completely dissolved, and generating silver chloride precipitate under the stirring condition; removing silver chloride precipitate, adding 20ml boiling ultrapure water into the alloy granule system, boiling until the upper layer liquid is clear, cooling to room temperature, and detecting gold content and recording as M2(ii) a Adding until the concentration of hydrochloric acid is 10 wt%, and the volume is constant V (L), shaking up, and detecting the gold content C (mg/L) in the lower layer material by adopting AAS (anaerobic ammonium sulfate), namely the gold content M in the gold stripping solution2(C x V) 0.90 mg;
(11)M1And M2The sum of the masses of (A) and (B) is 128.91mg, namely the content of gold in the gold-plated part is (M)1+M2)/M0＝3050g/t。
Comparative example 1
this comparative example provides a method for detecting the gold content in a gold-plated article, the gold-plated article to be tested being the same as the gold-plated article of example 1, differing from example 1 only in that: the gold-plated piece is directly placed in 500ml of clay prepared with materials without a gold stripping step, and then smelting, ash blowing, gold separation, concentration of separated gold liquid after gold separation and AAS detection (the same as in example 1) are adopted. The detection result shows that the content of gold in the gold-plated part is 1534 g/t.
As can be seen, the method for the comparative example only detects that the gold content in the gold-plated part is 48.06 percent of that in example 1, and the detection error is large.
comparative example 2
This comparative example provides a method for detecting the gold content in a gold-plated article, the gold-plated article to be tested being the same as the gold-plated article of example 1, differing from example 1 only in that: in the comparative example, a mixed solution of sulfuric acid and hydrogen peroxide (200ml of 9mol/L sulfuric acid with 40ml of 30% hydrogen peroxide) was used as a gold stripping solution, and the rest was the same as in example 1. The result shows that the gold stripping rate is relatively slow, the stripping of the gold-plated layer is finished after 20 hours of gold stripping, and finally the gold content in the gold-plated part is detected to be 2898 g/t.
as can be seen, the method of the comparative example only detects that the gold content in the gold-plated piece is 90.79% of that in example 1, and the detection error is large.
Comparative example 3
this comparative example provides a method for detecting the gold content in a gold-plated article, the gold-plated article to be tested being the same as the gold-plated article of example 1, differing from example 1 only in that: in the step (3), when the ashed sample is treated, electrolytic lead and silver powder are directly added without adding lead oxide and flour, a layer of mixture of anhydrous sodium carbonate and borax is covered on the electrolytic lead and silver powder, and then smelting, ash blowing, gold separation, concentration of separated gold liquid after gold separation, small-scale gold treatment and AAS detection are carried out (the same as in the embodiment 1). The detection result shows that the content of gold in the gold-plated part is 2803 g/t.
As can be seen, the method of the comparative example only detects that the gold content in the gold-plated piece is 87.81% of that in example 1, and the detection error is large.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (15)
1. A method for detecting gold content in a gold-plated part is characterized by comprising the following steps:
(1) immersing the gold-plated piece into a nitric acid solution, heating until the gold-plated layer is completely stripped, removing the gold-plated piece substrate, filtering the liquid while the liquid is hot, filtering the gold-plated layer on filter paper, and collecting filtrate as a gold stripping solution;
(2) Drying the filter paper with the gold-plated layer, ashing and cooling to obtain an ashed sample;
(3) adding a mixture of lead oxide and flour into the ashed sample obtained in the step (2), uniformly stirring, adding electrolytic lead and silver powder, covering a layer of mixture of anhydrous sodium carbonate and borax, smelting, cooling and removing slag to obtain a lead button;
(4) Ventilating and blowing ash to the lead button in the step (3), and when a color film appears on the surface of the lead button, carrying out heat preservation under a closed condition and then cooling to obtain gold and silver combined particles;
(5) Annealing and cooling the gold and silver alloy particles, and forming into an alloy coil;
(6) and (3) carrying out gold separation treatment on the alloy roll by using nitric acid, which specifically comprises the following steps: adding preheated dilute nitric acid into the alloy coil, continuously heating until the alloy coil is completely dissolved, standing for layering, pouring the upper-layer gold layering solution into the gold stripping solution in the step (1), and adding preheated concentrated nitric acid into the lower-layer precipitate; after continuing heating, standing and layering, pouring the upper layer of gold layering liquid into the gold stripping liquid in the step (1), and adding preheated concentrated nitric acid into the lower layer of precipitate; after continuing heating, standing and layering, pouring the upper layer of gold-separating liquid into the gold-stripping liquid in the step (1), and washing the lower layer of precipitate by using boiling ultrapure water to obtain gold after gold separation;
(7) drying the gold subjected to gold separation in the step (6), then firing, cooling, weighing, and recording as M1；
(8) Heating and concentrating the mixed solution of the gold stripping solution and the gold separating solution in the step (6) to obtain a concentrated solution; then transferring the concentrated solution into a container containing electrolytic lead, lead oxide and silver powder, evaporating to dryness, then continuously smelting, cooling and deslagging to obtain alloy particles;
(9) Carrying out ventilation and ash blowing on the alloy particles obtained in the step (8), and when a color film appears on the surface of the alloy particles, carrying out heat preservation and cooling under a closed condition to obtain ash-blown alloy particles;
(10) Adding nitric acid solution into the alloy particles after ash blowing, heating until the alloy particles are completely dissolved, adding hydrochloric acid to generate precipitate, removing the precipitate, adding boiling ultrapure water into an alloy particle system, boiling, cooling, and detecting the gold content and recording as M2；
(11)M1And M2the sum of the masses of (a) and (b) is the gold content in the gold-plated piece.
2. The method for detecting gold content in gold-plated parts according to claim 1, wherein in the step (1), the concentration of the nitric acid is 4.8-5.07 mol/L;
The heating temperature is 180-220 deg.C, and the heating time is 5-8 h.
3. The method according to claim 1, wherein the ashing is carried out at a temperature of 400 to 500 ℃ for 0.5 to 1.5 hours in step (2).
4. The method for detecting the gold content in gold-plated parts according to claim 1, wherein in the step (3), the mass ratio of the lead oxide to the flour is 8:1-12: 1;
the mass ratio of the silver powder to the ashed sample is 3:1-5: 1.
5. the method according to claim 1, wherein the melting is carried out at 850-950 ℃ for 15-25min in step (3).
6. The method for detecting gold content in gold-plated parts according to claim 1, wherein in the step (4), the time for performing the ash blowing is 85-95 min;
the temperature of the heat preservation is 850-950 ℃, and the time of the heat preservation is 2-8 min.
7. The method for detecting gold content in gold-plated parts according to claim 1, wherein in step (5), annealing treatment is performed at 700-800 ℃ for 5-15 min.
8. The method for detecting gold content in gold-plated part according to claim 1, wherein in the step (6), the concentration of the dilute nitric acid is 4.8-5.07mol/L, and the temperature of the preheated dilute nitric acid is 85-95 ℃;
the concentration of the concentrated nitric acid is 9.60-10.13mol/L, and the temperature of the preheated concentrated nitric acid is 85-95 ℃.
9. The method according to claim 1, wherein in step (6), after each addition of nitric acid, heating is carried out to a solution temperature of 85-95 ℃ for 20-40 min.
10. The method according to claim 1, wherein the temperature for performing said burning is 750-850 ℃ and the time for performing said burning is 2-8min in step (7).
11. the method according to claim 1, wherein the step (8) of concentrating by heating is carried out at a temperature of 180-220 ℃.
12. The method according to claim 1, wherein the temperature for evaporating to dryness in step (8) is 280-320 ℃.
13. The method for detecting the gold content in gold-plated parts according to claim 1, wherein in the step (8), before the smelting, a layer of anhydrous sodium carbonate and borax mixture is covered on the material;
the temperature for carrying out the smelting is 850-950 ℃, and the time for carrying out the smelting is 15-25 min.
14. the method for detecting gold content in gold-plated parts according to claim 1, wherein in the step (9), the time for performing the ash blowing is 85-95 min;
the temperature of the heat preservation is 850-950 ℃, and the time of the heat preservation is 2-8 min.
15. the method for detecting gold content in gold-plated parts according to claim 1, wherein in the step (10), the concentration of the nitric acid is 2.4-2.53 mol/L;
adding nitric acid, heating at 180-220 deg.C for 5-8 hr.
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