Method for determining gold content in high-impurity copper anode slime

Abstract

This application provides a method for determining the gold content in high-impurity copper anode slime, belonging to the field of precious metal analysis and detection technology. The method includes: digesting the high-impurity copper anode slime sample with aqua regia to obtain a gold-containing digestion solution; extracting the gold-containing digestion solution using MIBK to obtain a gold-loaded MIBK organic phase; mixing the gold-loaded MIBK organic phase with a fire assay mixture and heating at low temperature to completely volatilize the MIBK, leaving the gold in elemental form in the mixture; then sequentially performing fire assay melting, ash blowing, and gold separation steps; finally, calculating the gold content by weighing. This application directly couples "selective impurity removal by wet extraction" with "efficient enrichment by fire assay," eliminating interference from impurities such as copper, selenium, and tellurium on gold determination at the source. It has the advantages of short operation process, low detection cost, high accuracy and stability, meeting the needs for accurate, efficient, and batch determination of gold content in high-impurity copper anode slime.

Description

Technical Field

[0001] This application relates to the field of precious metal analysis and testing technology, and in particular to a method for determining the gold content in high-impregnation copper anode mud. Background Technology

[0002] Copper anode slime is an important byproduct of copper electrolytic refining. Its main source is the precipitation of undissolved impurities formed during the dissolution of the anode plates in the electrolytic cell. Its composition is complex and highly variable, containing not only precious metals such as gold and silver, but also large amounts of impurities including copper, selenium, tellurium, antimony, bismuth, arsenic, and lead, making it a typical high-impurity material. Gold is one of the core recovery targets in copper anode slime, and the accurate determination of its content directly affects the assessment of resource recovery efficiency, the fairness of trade settlement, and the optimization of production processes. It is one of the core technological requirements of the copper smelting industry and the field of precious metal testing.

[0003] Currently, the industry mainly uses the fire assay method to determine the gold content in high-impurity copper anode slime. However, this method has significant technical limitations and cannot meet the requirements for high-precision, high-efficiency, and low-cost batch testing. Specifically, the fire assay method is a classic traditional method for determining precious metals. Its core principle is to add fire assay reagents such as sodium carbonate, borax, lead oxide, and flour to the sample. Under high-temperature melting conditions, precious metals such as gold and silver are captured by lead to form lead granules. After the lead granules are blown away to remove base metals such as lead, gold and silver granules are obtained. The gold content is then determined by separating and weighing the granules.

[0004] The advantage of this method lies in its good enrichment effect on precious metals, making it suitable for the determination of precious metals in various materials. However, when applied to high-impurity copper anode slime, it has the following drawbacks: impurities such as copper, selenium, tellurium, antimony, and bismuth in high-impurity copper anode slime can seriously interfere with the melting process. The presence of copper can cause the lead buckle to be too hard or too brittle, affecting the smooth progress of subsequent ash blowing operations. Selenium and tellurium can form non-volatile selenium-tellurium-silver alloys with silver, which remain in the aggregate and are difficult to remove, resulting in higher gold content determination results. Antimony and bismuth can partially remain in the aggregate during the ash blowing process, causing gold particles to break during the gold separation stage, resulting in loss of precious metals and large deviations in the determination results.

[0005] To reduce the interference of the aforementioned impurities, existing technologies typically require multiple pre-removal treatments for copper anode mud samples, such as nitric acid leaching to remove copper, oxidative roasting to remove selenium and tellurium, and sulfation roasting to remove antimony and bismuth. Each pre-removal step involves cumbersome steps such as filtration, washing, and ashing, which is not only complex and time-consuming but also leads to gold loss during multiple treatments, making it difficult to meet the requirements of high-precision detection.

[0006] In summary, existing methods for determining gold content in high-impurity copper anode slime suffer from several technical drawbacks, including severe interference from impurities, cumbersome operation, high testing costs, and poor practicality. These methods fail to balance accuracy, ease of operation, and cost-effectiveness. Therefore, developing a method that can eliminate impurity interference at the source, simplify the operation process, reduce testing costs, and enable the determination of gold content in high-impurity copper anode slime has become a pressing technical problem in this field. Summary of the Invention

[0007] In view of the technical problems existing in the background art, this application provides a method for determining the gold content in high-impurity copper anode mud, aiming to solve the technical problems of inaccurate gold content determination and cumbersome operation procedures caused by severe impurity interference in the prior art.

[0008] To achieve the above objectives, this application provides a method for determining the gold content in high-impure copper anode slime, comprising the following steps: S1, the high-impurity copper anode mud is digested with aqua regia to obtain a gold-containing digestion solution; S2, the gold-containing digestion solution was extracted using methyl isobutyl ketone to separate the gold-loaded methyl isobutyl ketone organic phase; S3, mix the gold-loaded methyl isobutyl ketone organic phase obtained in step S2 with the fire assay gold mixture to obtain a mixture; S4. After transferring the mixture to a clay crucible, place it in a melting furnace. First, heat it to 150℃-200℃ and hold it for 15min-20min. Then, heat it to 300℃-350℃ at a rate of 4℃ / min-5℃ / min and hold it for 15min-20min to completely volatilize the methyl isobutyl ketone, so that the gold remains in the mixture in elemental form, and obtain the mixture after solvent removal. S5, a coating agent is applied to the mixture after solvent removal, followed by melting, ash blowing, and gold separation operations to obtain gold particles, which are then weighed; S6. The gold content in the high-impurity copper anode mud is calculated based on the mass of the high-impurity copper anode mud and the mass of the gold particles.

[0009] Further, step S1 includes the following process: weigh the high-impregnation copper anode mud sample, add aqua regia, and digest at 150°C until the sample is completely dissolved; after digestion, evaporate the solution in the container until there is no obvious liquid residue; then, add 5% hydrochloric acid by volume, and evaporate again until there is no obvious liquid residue, repeat the above operation of adding hydrochloric acid and evaporating until there is no obvious liquid residue twice to remove nitric acid; finally, add 5% hydrochloric acid by volume to obtain the gold-containing digestion solution.

[0010] Further, step S2 includes the following process: transferring the gold-containing digestion solution obtained in step S1 to a separatory funnel, adding methyl isobutyl ketone, and shaking to ensure that the gold-containing digestion solution and methyl isobutyl ketone are in full contact; after stopping the shaking, allowing it to stand and separate into layers, the system in the separatory funnel is divided into upper and lower layers, the upper layer is the gold-loaded methyl isobutyl ketone organic phase, and the lower layer is the aqueous phase, and the gold-loaded methyl isobutyl ketone organic phase is separated and retained.

[0011] Furthermore, the settling time is ≥10 min.

[0012] Furthermore, in step S3, the fire assay mixture includes: 80g~100g lead oxide, 30g~40g sodium carbonate, 10g~15g borax, 3g~4g flour, and 3g~5g silicon dioxide.

[0013] Furthermore, in step S1, the mass of the high-impregnation copper anode mud is 0.5g-2g.

[0014] Furthermore, in step S5, the thickness of the covering agent is 5mm to 10mm; the covering agent is a mixture of sodium carbonate and borax in a mass ratio of 2:1 or 3:2.

[0015] Furthermore, in step S5, the melting temperature is controlled at 1100℃~1200℃, and the holding time is 5 min~10 min.

[0016] Furthermore, in step S5, the preheating temperature of the ash pan is 950℃~1000℃, and the ash blowing temperature is 880℃~900℃.

[0017] The beneficial effects of this application are: This application provides a method for determining the gold content in high-impurity copper anode mud. Before fire assay analysis, the high-impurity copper anode mud is mixed with aqua regia to leach the gold. Then, methyl isobutyl ketone (MIBK) is added. Utilizing the strong extraction ability of MIBK for gold, all the gold is extracted into the MIBK organic phase. Subsequently, the gold-containing MIBK is mixed evenly with a fire assay mixture (sodium carbonate, borax, lead oxide, silica, and flour) and placed in a clay crucible. The clay crucible is then calcined at a low temperature (first heated to a certain temperature). The mixture is heated to 150℃-200℃ and held for 15-20 minutes, then heated to 300℃-350℃ at a rate of 4℃ / min-5℃ / min and held for 15-20 minutes to volatilize the MIBK, leaving the gold in the mixture, resulting in a solvent-free mixture. The solvent-free mixture is then melted, blown away, and the gold is separated to determine the gold content, enabling rapid and accurate determination of the gold content in high-impurity copper anode mud, thus improving the accuracy and stability of the test results.

[0018] This application is based on the synergistic effect of "selective impurity removal by wet extraction + efficient enrichment by fire assay", and utilizes the ion association extraction mechanism of methyl isobutyl ketone (MIBK) to selectively remove [AuCl4]. - The mixture is transferred to an organic phase to separate impurities such as copper, selenium, and tellurium. Then, the gold-extracted MIBK is uniformly mixed with the fire assay mixture to ensure complete gold capture during the fire assay analysis stage. Because the organic matter in MIBK is carbonized into fine particulate carbon during the fire assay melting stage, this particulate carbon adheres to the surface of lead particles, hindering their aggregation. This results in lead particles containing the precious metal remaining in the slag, unable to completely aggregate into lead buckles, leading to precious metal loss. This application completely volatilizes MIBK through a gradient low-temperature heating method at 200–350°C to remove the solvent, allowing gold to remain in elemental form. The formula is uniformly retained in the mixture, which avoids interference from organic phases in the flame gold melting process and prevents gold loss with MIBK vapor, thus ensuring the gold recovery rate and measurement accuracy. Next, flame gold melting is carried out, using lead oxide as a collector. With the synergistic effect of fluxes and reducing agents such as sodium carbonate, borax, silica, and flour, it is melted at a high temperature of 1100-1200℃ to form lead buckles, which efficiently enriches the gold. Finally, the lead is removed by ash blowing at 880℃-900℃ to obtain gold-silver granules. The silver is then separated with dilute nitric acid, and the gold content is accurately determined by gravimetric method.

[0019] This application separates impurities such as copper, selenium, tellurium, antimony, and bismuth at the source, solving the problem of interference from high impurities. It eliminates the back-extraction, ashing, and resolution steps after traditional wet extraction, as well as the multiple pre-purification, filtration, and ashing steps in the direct fire assay method, shortening the process by more than 40% and reducing reagent consumption. Furthermore, it does not rely on high-end detection instruments such as ICP-OES, requiring only basic equipment such as a melting furnace, electronic balance, and clay crucible, reducing detection costs and making it highly practical. It meets the needs for accurate, efficient, and batch determination of gold content in high-impurity copper anode slime. Attached Figure Description

[0020] Figure 1 This is a photograph of the gold-silver granules obtained in Example 1.

[0021] Figure 2 This is a photograph of the gold-silver granules obtained in Comparative Example 2. Detailed Implementation

[0022] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0023] It should also be noted here that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0024] This application provides a method for determining the gold content in high-impure copper anode slime, comprising the following steps: S1, the high-impurity copper anode mud is digested with aqua regia to obtain a gold-containing digestion solution; Specifically, step S1 includes the following process: weigh the high-impregnation copper anode mud sample, add aqua regia, and digest at 150°C until the sample is completely dissolved; after digestion, evaporate the solution in the container until there is no obvious liquid residue; then, add 5% hydrochloric acid by volume, and evaporate again until there is no obvious liquid residue, repeat the above operation of adding hydrochloric acid and evaporating until there is no obvious liquid residue twice to remove nitric acid; finally, add 5% hydrochloric acid by volume to obtain the gold-containing digestion solution.

[0025] The mass of the high-impurity copper anode mud is 0.5g-2g.

[0026] S2, the gold-containing digestion solution was extracted using methyl isobutyl ketone to separate the gold-loaded methyl isobutyl ketone organic phase; Specifically, step S2 includes the following process: transferring the gold-containing digestion solution obtained in step S1 to a separatory funnel, adding methyl isobutyl ketone, and shaking to ensure that the gold-containing digestion solution and methyl isobutyl ketone are in full contact; after stopping shaking, allowing the mixture to stand and separate into layers, the system in the separatory funnel is divided into upper and lower layers, the upper layer being the gold-loaded methyl isobutyl ketone organic phase and the lower layer being the aqueous phase, and separating and retaining the gold-loaded methyl isobutyl ketone organic phase.

[0027] The time for static stratification is ≥10 min.

[0028] S3, mix the gold-loaded methyl isobutyl ketone organic phase obtained in step S2 with the fire assay gold mixture to obtain a mixture; The fire assay mixture includes: 80g~100g lead oxide, 30g~40g sodium carbonate, 10g~15g borax, 3g~4g flour, and 3g~5g silicon dioxide.

[0029] S4. After transferring the mixture to a clay crucible, place it in a melting furnace. First, heat it to 150℃-200℃ and hold it for 15min-20min. Then, heat it to 300℃-350℃ at a rate of 4℃ / min-5℃ / min and hold it for 15min-20min to completely volatilize the methyl isobutyl ketone, so that the gold remains in the mixture in elemental form, and obtain the mixture after solvent removal. S5, a coating agent is applied to the mixture after solvent removal, followed by melting, ash blowing, and gold separation operations to obtain gold particles, which are then weighed; The thickness of the covering agent is 5mm to 10mm; the covering agent is a mixture of sodium carbonate and borax in a mass ratio of 2:1 or 3:2.

[0030] During the melting process, the melting temperature is controlled at 1100℃~1200℃, and the holding time is 5 min~10 min.

[0031] During the ash blowing process, the preheating temperature of the ash pan is 950℃~1000℃, and the ash blowing temperature is 880℃~900℃.

[0032] S6. The gold content in the high-impurity copper anode mud is calculated based on the mass of the high-impurity copper anode mud and the mass of the gold particles.

[0033] The method for determining the gold content in high-impregnation copper anode slime provided in this application first utilizes aqua regia to digest the sample, converting the gold into [AuCl4]. - The [AuCl4] form enters the solution; then MIBK is used to react with [AuCl4]. - The high selective extraction capability separates gold from a large number of coexisting impurities (copper, selenium, tellurium, etc.). The gold-loaded MIBK organic phase is directly mixed with the fire assay mixture. The MIBK is completely volatilized by a precisely controlled gradient low-temperature heating method to remove the solvent. This avoids the carbonization of organic matter during subsequent high-temperature melting, which would interfere with the aggregation of lead particles, and also prevents the loss of gold by vapor volatilization. This ensures that the gold remains uniformly in the mixture in elemental form. Subsequently, fire assay melting is performed, and the gold is efficiently captured by lead oxide to form lead buckles. After ash blowing and gold separation, the gold content is finally accurately determined by gravimetric method.

[0034] The method for determining the gold content in high-impregnation copper anode slime provided in this application will be described below with reference to specific embodiments.

[0035] Example 1 This embodiment provides a method for determining the gold content in high-impregnation copper anode slime, including the following steps: S1, Sample digestion: Weigh 1.0000 g of high-impurity copper anode mud sample and place it in a 250 mL beaker. Add 50 mL of aqua regia and place the beaker on a hot plate. Control the temperature at 150℃ for low-temperature digestion to ensure complete dissolution of the sample. After digestion, evaporate the solution in the beaker until there is no obvious liquid residue. Add 20 mL of 5% hydrochloric acid to the beaker and continue evaporating until nearly dry. Repeat twice to ensure complete removal of nitric acid. After cooling to room temperature, add 20 mL of 5% hydrochloric acid to obtain the gold-containing digestion solution.

[0036] S2, MIBK Extract: The gold-containing digest obtained in step S1 was transferred to a 100 mL separatory funnel, 25 mL of MIBK was added, and the mixture was shaken to ensure that the gold-containing digest and MIBK were in full contact. After shaking was stopped, the separatory funnel was allowed to stand for 10 min to separate the layers. It was observed that the system was divided into two layers: the upper layer was the gold-loaded MIBK organic phase (pale yellow), and the lower layer was the aqueous phase (colorless and transparent). The gold-loaded MIBK organic phase was separated and retained.

[0037] S3, Ingredients: The gold-loaded MIBK organic phase obtained in step S2 was mixed evenly with 40 g of sodium carbonate, 12 g of borax, 5 g of silicon dioxide, 80 g of lead oxide, and 4 g of flour to obtain a mixture.

[0038] S4, Low-temperature solvent removal: Transfer the mixture obtained in step S3 to a clay crucible, then place the clay crucible into a melting furnace and close the furnace door; first heat to 200℃, hold for 20 min, then heat to 350℃ at a rate of 5℃ / min, hold for 15 min. Hold at this temperature for 15 min; completely volatilize and remove MIBK from the mixture, leaving gold in elemental form in the mixture.

[0039] S5. Cover the mixture after removing the solvent MIBK with a 10mm thick covering agent (a mixture of sodium carbonate and borax in a mass ratio of 2:1).

[0040] Subsequently, melting, ash blowing, and gold separation operations are carried out to obtain gold-silver granules.

[0041] Specifically as follows: Melt treatment: Transfer the clay crucible to the melting furnace and slowly heat it to 1100℃. Maintain this temperature for 10 minutes. Gently rotate the clay crucible several times and lightly tap the bottom of the crucible on an iron plate 2-3 times to ensure the molten material gathers at the bottom. Then pour the entire molten material into a preheated cast iron mold. After cooling, separate the lead buckle from the slag, retaining the lead buckle. Hammer the lead buckle into a cube and weigh it.

[0042] Ash blowing treatment: The obtained lead buckle is placed in a magnesia ash dish that has been preheated in a box-type resistance furnace at 950℃ for 20 minutes. After the lead melts and the film is removed, the furnace door is partially opened and the ash is blown at 880℃. After the lead is completely blown away, the gold and silver granules are taken out.

[0043] Gold splitting process: Use a hammer to break the gold-silver granules into thin sheets with a thickness of 0.2 mm to 0.3 mm. Place the sheet in a colorimetric tube, add 10 mL of nitric acid solution A (a mixture of nitric acid and water in a volume ratio of 1:7), and heat the colorimetric tube in a water bath. After the granules and acid stop reacting, remove the colorimetric tube, pour out the acid, add 10 mL of gently boiling nitric acid solution B (a mixture of nitric acid and water in a volume ratio of 1:1), and continue heating in a boiling water bath for 40 min.

[0044] Remove the colorimetric tube, pour out the acid solution, wash the gold particles with distilled water, transfer them to a porcelain crucible, dry them on a hot plate and anneal them, cool them to room temperature, weigh the gold particles on a microbalance, and record the mass m1.

[0045] S6. The gold content in the high-impurity copper anode mud is calculated based on the mass of the high-impurity copper anode mud and the mass of the gold particles.

[0046] The gold content w in high-purity copper anode slime is calculated using the following formula. Au : ; Among them, w Au The gold content in the high-impure copper anode slime is kg / t; m0 is the mass of the high-impure copper anode slime in g; and m1 is the mass of the gold particles in mg.

[0047] A sample of high-impure copper anode mud was selected, and the gold content in the high-impure copper anode mud was determined according to the determination method in Example 1. A precision test was conducted to verify the stability of the test. The test results are shown in Table 1. Meanwhile, since there is currently a lack of standard samples of high-impure copper anode mud, in order to verify the accuracy of the method provided in this example, the spiked recovery method was adopted for verification. The test results are shown in Table 2.

[0048] Table 1 Table 2 As can be seen from the data in Tables 1 and 2, the precision of Example 1 is 0.84%, and the spiked recovery rate is 99.78%~100.0%, proving that the determination method provided in this example has high stability and accuracy. The experimental phenomena show that the granules obtained after MIBK purification are smooth and free of impurities, such as... Figure 1 As shown, this indicates that the impurity removal effect is very good.

[0049] Comparative Example 1 The difference from Example 1 is that step S4 (low-temperature solvent removal) was not performed, that is, the melting process was carried out directly after the ingredients were mixed; otherwise, it is basically the same as Example 1, and will not be repeated here.

[0050] The same high-impure copper anode mud sample as in Example 1 was selected, and the gold content in the high-impure copper anode mud was determined according to the determination method of Comparative Example 1. The results are shown in Table 3.

[0051] Table 3 As can be seen from the data in Table 3, the gold content was 7.507 g / t, with a relative standard deviation of 1.19%. Compared with Example 1, the result was lower and the precision was poor.

[0052] This is mainly due to the absence of a low-temperature removal step for organic reagents. Organic reagents form fine carbon particles during the melting stage of the fire assay, which adsorb onto the surface of the lead particles, making it difficult for the lead particles to aggregate. This, in turn, leads to lower measurement results and poor precision. Therefore, low-temperature removal of organic reagents is an essential step.

[0053] Comparative Example 2 The difference from Example 1 is that the sample digestion in step S1, the MIBK extraction in step S2, and the low-temperature solvent removal in step S4 were not performed. Instead, the high-impurity copper anode mud sample was directly mixed with the fire assay mixture and then melted, blown away, and separated to obtain gold particles. The rest is basically the same as in Example 1, and will not be repeated here.

[0054] The same high-impure copper anode mud sample as in Example 1 was selected, and the gold content in the high-impure copper anode mud was determined according to the determination method of Comparative Example 2. The results are shown in Table 4.

[0055] Table 4 As can be seen from the data in Table 4, the relative standard deviation is 3.05%, which is less precise than that of Example 1. This is mainly because no impurity removal operation was performed, resulting in a higher impurity content in the sample and thus a higher impurity content in the aggregate. This leads to gold particle breakage during gold separation (e.g., Figure 2 As shown in the figure, this results in a lower value; at the same time, it can also lead to impurities remaining in the gold particles after gold separation, resulting in a higher value; the above reasons directly lead to poor accuracy of the results. This also fully illustrates the necessity of removing impurities from high-pollution copper anode mud samples.

[0056] Comparative Example 3 The difference from Example 1 is that in step S4, the solvent was not removed by gradient heating, but by direct constant calcination at 200°C for 65 minutes; the rest is basically the same as Example 1, and will not be repeated here.

[0057] Comparative Example 4 The difference from Example 1 is that in step S4, the solvent was not removed by gradient heating, but by direct constant calcination at 400°C for 65 minutes; the rest is basically the same as Example 1, and will not be repeated here.

[0058] The same high-impure copper anode mud sample as in Example 1 was selected, and the gold content in the high-impure copper anode mud was determined according to the determination methods of Comparative Examples 3 and 4. The results are shown in Table 5.

[0059] Table 5 As can be seen from the data in Table 5, the measurement results of Comparative Example 3 are significantly lower. This is mainly because the temperature of 200℃ is too low when removing organic solvents, and the organic solvents are not completely removed. The remaining organic solvents will form fine carbon particles during the melting stage, which will be adsorbed on the surface of lead particles, making it difficult for lead particles to aggregate, thus resulting in lower measurement results and poor precision.

[0060] The precision of the determination results in Comparative Example 4 was poor. This was mainly because the direct high-temperature calcination caused the gold-containing resin to burn rapidly, resulting in splashing and loss of the gold-absorbing resin, which in turn led to lower results and poor precision.

[0061] It is evident that using a gradient heating method to remove solvent can gently and thoroughly remove the solvent, which is key to ensuring the accuracy and stability of the results.

[0062] Example 2 Example 2 provides a method for determining the gold content in high-purity copper anode slime, which differs from Example 1 in that the grade of the high-purity copper anode slime sample used is 1.125 kg / t. Everything else is the same as in Example 1 and will not be repeated here.

[0063] Example 3 Example 3 provides a method for determining the gold content in high-impurity copper anode slime. The difference from Example 1 is that the high-impurity copper anode slime used comes from different electrolysis workshops, the raw materials used in electrolysis are different, and the impurity content of the high-impurity copper anode slime is different, as shown in Table 6. Everything else is the same as in Example 1 and will not be repeated here.

[0064] Table 6 Note: The data units in the table are %; "-" indicates a content of 0.

[0065] The results of precision tests and spike recovery tests for Examples 2 and 3 are shown in Tables 7 and 8.

[0066] Table 7 Table 8 Results of Spike Recovery Test As can be seen from the data in Tables 7 and 8, the precision of Examples 2 and 3 is 0.82% and 0.16%, respectively, and the spike recovery rates are 99.72% and 99.59%, respectively, further proving that the determination method provided in this application has accuracy and stability.

[0067] It can be seen that the method provided in this application has high accuracy for different types and grades of high-impurity copper anode mud, and also exhibits high stability.

[0068] In summary, this application provides a method for determining the gold content in high-impurity copper anode slime. Before fire assay analysis, the high-impurity copper anode slime is mixed with aqua regia to leach the gold. Then, MIBK is added, utilizing its strong gold extraction ability to completely extract the gold into the MIBK organic phase. The gold-containing MIBK is then uniformly mixed with a fire assay mixture (sodium carbonate, borax, lead oxide, silica, and flour) and placed in a clay crucible. A gradient low-temperature heating method is used to completely volatilize the MIBK, leaving the gold in the mixture. Subsequently, the gold-containing mixture is melted, ash-blown, and separated to determine the gold content. This method achieves rapid and accurate determination of the gold content in high-impurity copper anode slime, improving the accuracy and stability of the detection results.

[0069] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A method for determining the gold content in high-impure copper anode slime, characterized in that, Includes the following steps: S1, the high-impurity copper anode mud is digested with aqua regia to obtain a gold-containing digestion solution; S2, the gold-containing digestion solution was extracted using methyl isobutyl ketone to separate the gold-loaded methyl isobutyl ketone organic phase; S3, mix the gold-loaded methyl isobutyl ketone organic phase obtained in step S2 with the fire assay gold mixture to obtain a mixture; S4. After transferring the mixture to a clay crucible, place it in a melting furnace. First, heat it to 150℃-200℃ and hold it for 15min-20min. Then, heat it to 300℃-350℃ at a rate of 4℃ / min-5℃ / min and hold it for 15min-20min to completely volatilize the methyl isobutyl ketone, so that the gold remains in the mixture in elemental form, and obtain the mixture after solvent removal. S5, a coating agent is applied to the mixture after solvent removal, followed by melting, ash blowing, and gold separation operations to obtain gold particles, which are then weighed; S6. The gold content in the high-impurity copper anode mud is calculated based on the mass of the high-impurity copper anode mud and the mass of the gold particles.

2. The method for determining the gold content in high-impregnation copper anode slime according to claim 1, characterized in that, Step S1 includes the following process: weigh the high-impregnation copper anode mud sample, add aqua regia, and digest at 150°C until the sample is completely dissolved; after digestion, evaporate the solution in the container until there is no obvious liquid residue. Subsequently, 5% hydrochloric acid was added, and the mixture was evaporated again until no obvious liquid residue remained. This process of adding hydrochloric acid and evaporating until no obvious liquid residue remained was repeated twice to remove nitric acid. Finally, 5% hydrochloric acid was added to obtain the gold-containing digestion solution.

3. The method for determining the gold content in high-impregnation copper anode slime according to claim 1, characterized in that, Step S2 includes the following process: the gold-containing digestion solution obtained in step S1 is transferred to a separatory funnel, methyl isobutyl ketone is added, and the mixture is shaken to ensure that the gold-containing digestion solution and methyl isobutyl ketone are in full contact; after shaking is stopped, the mixture is allowed to stand and separate into layers. The system in the separatory funnel is divided into two layers: the upper layer is the gold-loaded methyl isobutyl ketone organic phase, and the lower layer is the aqueous phase. The gold-loaded methyl isobutyl ketone organic phase is separated and retained.

4. The method for determining the gold content in high-impregnation copper anode slime according to claim 3, characterized in that, The static stratification time is ≥10 min.

5. The method for determining the gold content in high-impregnation copper anode slime according to claim 1, characterized in that, In step S3, the fire assay mixture includes: 80g~100g lead oxide, 30g~40g sodium carbonate, 10g~15g borax, 3g~4g flour, and 3g~5g silicon dioxide.

6. The method for determining the gold content in high-impregnation copper anode slime according to claim 1, characterized in that: In step S1, the mass of the high-impregnation copper anode mud is 0.5g-2g.

7. The method for determining the gold content in high-impregnation copper anode slime according to claim 1, characterized in that: In step S5, the thickness of the covering agent is 5mm to 10mm; the covering agent is a mixture of sodium carbonate and borax in a mass ratio of 2:1 or 3:

2.

8. The method for determining the gold content in high-impregnation copper anode slime according to claim 1, characterized in that, In step S5, the melting temperature is controlled at 1100℃~1200℃, and the holding time is 5 min~10 min.

9. The method for determining the gold content in high-impure copper anode slime according to claim 1, characterized in that: In step S5, the preheating temperature of the ash pan is 950℃~1000℃, and the ash blowing temperature is 880℃~900℃.

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