Method for processing silver in a silver smelting residue of recycled gold

Abstract

The present application relates to a kind of methods for recovering silver in gold smelting silver residue, using hydrochloric acid to soak gold smelting silver residue, separation obtains silver-containing filter residue, then using (1+2) ammonia water to leach silver-containing filter residue, separation leaching liquid and insoluble residue, secondary leaching is carried out to insoluble residue, and leaching liquid is collected uniformly.Add industrial sodium chloride to leaching liquid, add appropriate amount of hydrochloric acid to adjust acidity, so that pH <12, promote silver chloride precipitation completely.Silver chloride precipitate is filtered and washed, to obtain washed silver chloride, add appropriate amount of ammonia water to dissolve, add reducing agent to reduce, to obtain gray sponge silver, through detection calculation, silver recovery rate ≥99.9%, the silver content of recovered sponge silver is ≥99.5% after detection, the specific surface area of obtained sponge silver is large, and it has good catalytic activity.

Description

Technical Field

[0001] This invention relates to the field of metallurgical recycling technology, specifically to a method for treating and recovering silver from silver slag in gold smelting. Background Technology

[0002] In the gold smelting industry, the most common hydrometallurgical method is the aqua regia smelting method. This method is generally used to purify crude gold (also called composite gold) containing no more than 8% silver: the crude gold is dissolved in aqua regia, the gold enters the solution, and the silver is separated as silver chloride slag. At the same time, the platinum group metals contained in the crude gold can be separated and recovered.

[0003] The processing technology for separating silver slag is mainly divided into two types: pyrometallurgical and hydrometallurgical methods. Hydrometallurgical methods are further divided into fully hydrometallurgical and semi-hydrometallurgical methods. The industry primarily uses a combined hydrometallurgical and pyrometallurgical approach to extract valuable metals from separated silver slag. This is mentioned in articles such as Ning Rui of Daye Nonferrous Metals in "Research Status of Recovering Valuable Metals from Separated Silver Slag," Wu Yujiao of Yunnan Tin Wenshan Zinc & Indium in "Exploration of Silver Extraction Process from Pyrometallurgical Zinc-Lead-Silver Slag," and Fang Mengzhao of Daye Nonferrous Metals in "Industrial Experimental Study on Recovering Valuable Metals from Separated Silver Slag." Zhang Hua of the Sichuan Metallurgical Institute mentioned various hydrometallurgical silver recovery methods in "Research on Methods for Recovering Silver from Rich Silver Slag." However, the silver slag materials studied in these articles are significantly different from those in gold smelting silver slag. While Zhang Hua's research on rich silver slag showed a high precious metal content (0.66% silver and 31 g / t gold), it still differed greatly from the precious metal content in gold smelting silver slag.

[0004] Due to the high content of precious metals such as gold and silver in silver slag, the current main treatment method is pyrometallurgical enrichment and recovery of gold and silver, followed by gold separation of the recovered gold-silver granules, and reduction of the silver nitrate solution in the gold separation solution to obtain sponge silver. The entire process of silver enrichment and recovery in silver slag separation is cumbersome, time-consuming, and costly. There is an urgent need for a technological reform to improve the silver recovery efficiency from smelting silver slag and reduce the cost and time required for silver recovery.

[0005] The purpose of this invention is to design a method for treating and recovering silver from silver slag in gold smelting, addressing the problems existing in the prior art. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a method for processing and recovering silver from gold smelting silver slag, which can effectively solve at least one of the problems existing in the prior art. The method can achieve efficient and low-cost enrichment, purification and recovery of silver from gold smelting silver slag.

[0007] The technical solution of this invention is:

[0008] A method for recovering silver from silver slag in gold smelting, characterized by comprising the following steps:

[0009] (1) The silver slag from gold smelting was soaked in hydrochloric acid and filtered to obtain silver-containing filter residue;

[0010] (2) Soak the silver-containing filter residue obtained in step (1) with ammonia water. Utilize the complexing effect of ammonia water on silver to convert the insoluble silver in the silver-containing filter residue into soluble silver ammonium complex ions, so that the silver enters the solution in the form of silver ammonium complex ions. Filter and separate from the insoluble residue to obtain silver-containing filtrate.

[0011] (3) Add an appropriate amount of industrial sodium chloride to the silver-containing filtrate to adjust the pH value of the solution and promote the complete precipitation of silver chloride.

[0012] (4) Filter and wash the silver chloride precipitate to remove impurities attached to the silver chloride;

[0013] (5) The washed silver chloride was dissolved in ammonia water, and a mixed solution of hydrazine hydrate and sodium borohydride was added for reduction to obtain gray sponge silver, thus realizing the recovery of silver from silver slag in gold smelting.

[0014] Silver slag from gold smelting is an insoluble slag produced after hydrometallurgical processes. It mainly contains silver, undissolved gold, and other insoluble impurities present in the gold ore. In order to better control the silver slag recovery process, accurately control the volume of ammonia leaching solution, and accurately control the addition of reagents such as sodium chloride, necessary pretreatment and elemental analysis are performed on the silver slag samples.

[0015] Furthermore, the silver slag from gold smelting is pretreated. The pretreatment process involves drying the silver slag at 100-120℃ for 20-30 hours to remove impurities, obtaining a sample using a sealed sample preparation mechanism, and mixing it thoroughly. The sample is then tested for the content of gold, silver, and impurity elements, and the theoretical amount of reagents required is calculated based on the silver content.

[0016] The gold and silver content in silver slag was determined using the fire assay gravimetric method; the content of major impurity elements in the sample was determined using the acid dissolution method.

[0017] Further, in step (1), the silver slag is soaked once with 50-100 mL of hydrochloric acid and filtered. The insoluble residue obtained by filtration is soaked a second time with 50-100 mL of hydrochloric acid and filtered. The resulting filter residue is used as silver-containing filter residue.

[0018] Furthermore, in step (2), the amount of silver-containing filter residue is 1-5g, and the amount of ammonia water is 100-200mL; the ammonia water used is 1+2 ammonia water, that is, an ammonia solution obtained by mixing one part by weight of concentrated ammonia water with two parts by weight of distilled water.

[0019] Further, in step (2), the silver-containing filter residue is soaked once with 50-100 mL of ammonia water and filtered. The insoluble residue obtained from the filtration is soaked a second time with 50-100 mL of ammonia water and filtered. The filtrates obtained from the two soaking and filtration are combined as the silver-containing filtrate.

[0020] Furthermore, in step (3), the amount of sodium chloride used is 0.5 to 2 g, which is 1.2 to 1.5 times the theoretical amount.

[0021] Furthermore, in step (3), 15-25 ml of hydrochloric acid is added to adjust the pH of the solution so that pH < 12.

[0022] Furthermore, in step (4), the silver chloride precipitate is washed with water 2 to 8 times.

[0023] Further, in step (5), the amount of the mixed solution used is 1-10 mL, the content of hydrazine hydrate in the mixed solution is 30-50 wt%, and the content of sodium borohydride is 10-30 wt%.

[0024] Furthermore, in step (5), the sponge silver is ashed at 600-700℃.

[0025] Therefore, the present invention provides the following effects and / or advantages:

[0026] This invention uses hydrochloric acid to leach silver slag from gold smelting, separating silver-containing filter residue. The residue is then leached with (1+2) ammonia solution, separating the leaching liquid from the insoluble residue. The insoluble residue is leached a second time, and the leaching liquid is collected uniformly. Industrial sodium chloride is added to the leaching liquid, and an appropriate amount of hydrochloric acid is added to adjust the acidity to pH < 12, promoting complete precipitation of silver chloride. The silver chloride precipitate is filtered and washed to obtain clean silver chloride, which is dissolved in an appropriate amount of ammonia solution. A mixed solution of hydrazine hydrate and sodium borohydride is added for reduction, yielding gray sponge silver. Calculations show a silver recovery rate ≥ 99.9%, and the recovered sponge silver has a silver content ≥ 99.5%. The obtained sponge silver has a large specific surface area and exhibits good catalytic activity.

[0027] This invention first soaks silver slag in hydrochloric acid to remove impurities such as iron and copper, while exposing the silver inside. After filtration, an insoluble residue is obtained. This insoluble residue is then soaked in hydrochloric acid again to further separate the insoluble silver, resulting in a silver-containing filter residue. Ammonia water is then used to complex the silver, converting the insoluble silver in the silver-containing filter residue into soluble silver ammonium complex ions. Filtration then separates the filtrate containing the silver ammonium complex ions from the filter residue containing other impurities. The filter residue is then soaked in ammonia water a second time to maximize the extraction of silver. The residual silver element was removed, and the filtrates were combined to obtain a silver-containing filtrate. The silver-containing filtrate was then precipitated using sodium chloride, and the pH of the solution was adjusted by hydrochloric acid to promote the precipitation of silver ions in the form of silver chloride. The precipitate was then filtered and washed to remove attached impurity ions, resulting in purified silver chloride. Finally, the silver chloride was reduced using a mixed solution of hydrazine hydrate and sodium borohydride to obtain high-purity sponge silver. The obtained sponge silver had extremely low impurity content, achieving efficient and low-cost enrichment, purification, and recovery of silver from gold smelting slag.

[0028] It should be understood that the above summary and the following detailed description of the invention are exemplary and explanatory, and are intended to provide further explanation of the invention as claimed. Detailed Implementation

[0029] To facilitate understanding by those skilled in the art, the embodiments are now described in further detail to illustrate the technical solution of the present invention. It should be understood that, unless otherwise specified, the order of the steps mentioned in this embodiment can be adjusted according to actual needs, and they may even be executed simultaneously or partially simultaneously. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] In this embodiment, for the purposes of this document, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make further changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0031] The specific embodiments of the present invention are as follows:

[0032] A method for recovering silver from silver slag in gold smelting, characterized by comprising the following steps:

[0033] (1) The silver slag from gold smelting was soaked in hydrochloric acid and filtered to obtain silver-containing filter residue;

[0034] (2) Soak the silver-containing filter residue obtained in step (1) with ammonia water. Utilize the complexing effect of ammonia water on silver to convert the insoluble silver in the silver-containing filter residue into soluble silver ammonium complex ions, so that the silver enters the solution in the form of silver ammonium complex ions. Filter and separate from the insoluble residue to obtain silver-containing filtrate.

[0035] (3) Add an appropriate amount of industrial sodium chloride to the silver-containing filtrate to adjust the pH value of the solution and promote the complete precipitation of silver chloride.

[0036] (4) Filter and wash the silver chloride precipitate to remove impurities attached to the silver chloride;

[0037] (5) The washed silver chloride was dissolved in ammonia water, and a mixed solution of hydrazine hydrate and sodium borohydride was added for reduction to obtain gray sponge silver, thus realizing the recovery of silver from silver slag in gold smelting.

[0038] Silver slag from gold smelting is an insoluble slag produced after hydrometallurgical processes. It mainly contains silver, undissolved gold, and other insoluble impurities present in the gold ore. In order to better control the silver slag recovery process, accurately control the volume of ammonia leaching solution, and accurately control the addition of reagents such as sodium chloride, necessary pretreatment and elemental analysis are performed on the silver slag samples.

[0039] Furthermore, the silver slag from gold smelting is pretreated. The pretreatment process involves drying the silver slag at 100-120℃ for 20-30 hours to remove impurities, obtaining a sample using a sealed sample preparation mechanism, and mixing it thoroughly. The sample is then tested for the content of gold, silver, and impurity elements, and the theoretical amount of reagents required is calculated based on the silver content.

[0040] The gold and silver content in silver slag was determined using the fire assay gravimetric method; the content of major impurity elements in the sample was determined using the acid dissolution method.

[0041] Further, in step (1), the silver slag is soaked once with 50-100 mL of hydrochloric acid and filtered. The insoluble residue obtained by filtration is soaked a second time with 50-100 mL of hydrochloric acid and filtered. The resulting filter residue is used as silver-containing filter residue.

[0042] Furthermore, in step (2), the amount of silver-containing filter residue is 1-5g, and the amount of ammonia water is 100-200mL; the ammonia water used is 1+2 ammonia water, that is, an ammonia solution obtained by mixing one part by weight of concentrated ammonia water with two parts by weight of distilled water.

[0043] Further, in step (2), the silver-containing filter residue is soaked once with 50-100 mL of ammonia water and filtered. The insoluble residue obtained from the filtration is soaked a second time with 50-100 mL of ammonia water and filtered. The filtrates obtained from the two soaking and filtration are combined as the silver-containing filtrate.

[0044] Furthermore, in step (3), the amount of sodium chloride used is 0.5 to 2 g, which is 1.2 to 1.5 times the theoretical amount.

[0045] Furthermore, in step (3), 15-25 ml of hydrochloric acid is added to adjust the pH of the solution so that pH < 12.

[0046] Furthermore, in step (4), the silver chloride precipitate is washed with water 2 to 8 times.

[0047] Further, in step (5), the amount of the mixed solution used is 1-10 mL, the content of hydrazine hydrate in the mixed solution is 30-50 wt%, and the content of sodium borohydride is 10-30 wt%.

[0048] Furthermore, in step (5), the sponge silver is ashed at 600-700℃.

[0049] Example 1:

[0050] (I) Silver Slag Detection

[0051] To better control the silver slag recovery process and accurately control the volume of the ammonia leaching solution and the addition of reagents such as sodium chloride, necessary elemental analysis was performed on the silver slag sample.

[0052] 1. Sample preparation

[0053] The silver slag contained impurities such as paper scraps and clumps. To facilitate the subsequent experiments, the sample was simply treated: the silver slag sample was dried at 105℃ for 24 hours to remove impurities, and then mixed thoroughly using a sealed sample preparation machine.

[0054] 2. Detection of gold and silver content in samples

[0055] The gold and silver content in silver slag was determined using the fire assay gravimetric method. The material code was 23XX097-0002. The test results are shown in Table 1.

[0056] Table 1. Gold and silver content in silver slag

[0057]

[0058]

[0059] The gold and silver test results showed good precision, indicating that the silver slag sample had good homogeneity after preparation. The test results showed that the gold content was 10.15% and the silver content was 58.30%.

[0060] 3. Detection of other elements in the sample

[0061] A small sample was weighed and dissolved using tetraacid to determine the content of major impurity elements. The detection precision was good, and the data are shown in Table 2.

[0062] Table 2 Content of other impurity elements in silver slag

[0063]

[0064] According to the test data, the sample contains small amounts of copper and iron impurities, and trace amounts of palladium, tin, and chromium impurities.

[0065] (II) Processing and Recycling

[0066] Due to the large-scale material processing and relatively long production process, it is not convenient to obtain relevant data quickly. Therefore, when conducting specific silver slag treatment and recycling process experiments, the processing volume is reduced, and the corresponding process experiments are completed in the laboratory.

[0067] 1. Preparation of silver-containing filter residue

[0068] Weigh 2.00g of sample, soak it in 50ml of hydrochloric acid for 1 hour, filter it, soak the filter residue in 50ml of hydrochloric acid again for 1 hour, filter it, and obtain the silver-containing filter residue after impurity removal.

[0069] 2. Leaching of silver-containing filter residue

[0070] Take the above silver-containing filter residue, soak it in 55ml of (1+2) ammonia solution for 2 hours, filter, soak the filter residue again in 50ml of (1+2) ammonia solution for 2 hours, filter, combine the filtrates and set aside. Collect the filter residue for subsequent gold recovery.

[0071] 3. Precipitation and impurity removal

[0072] Add 0.85g of sodium chloride to the filtrate and adjust the acidity of the filtrate with 25ml of hydrochloric acid to promote complete precipitation of silver chloride. Filter to separate the silver chloride precipitate from the filtrate. Wash the silver chloride precipitate five times with water and return the washed silver chloride precipitate to the original beaker for later use.

[0073] 4. Precipitation and reduction

[0074] Add appropriate amount of ammonia to a beaker containing silver chloride precipitate, stir to dissolve, and while stirring, slowly add 2.5 ml of a mixed solution (containing 40 wt% hydrazine hydrate and 20 wt% sodium borohydride) dropwise for reduction to obtain gray sponge silver (the sponge silver used for detection is directly dried). Filter, wash the sponge silver, and ashing at 650℃.

[0075] (III) Application examples of this invention are as follows

[0076] This process was used to conduct a process experiment on silver slag from gold smelting, numbered 23XX097-0002. The specific process experiment data are shown in Table 3.

[0077] Table 3 Process Experiment Data

[0078]

[0079] As shown in Table 3, by controlling the amount of reagent added, this process can effectively treat and recover silver from silver slag in gold smelting, with a silver recovery rate of >99.9%. At the same time, this process is simple to operate and uses few reagents, all of which are conventional reagents.

[0080] The impurity content of the obtained sponge silver was tested, and the total impurity content was approximately 0.012%. It can be seen that the sponge silver obtained using this process has a low content of impurity elements, and the silver content in the sponge silver is >99.9%.

[0081] The obtained sponge silver was used as a catalyst to catalyze the conversion of cinnamaldehyde to cinnamic acid.

[0082] (1) Add 1 gram of the sponge silver catalyst prepared by this process to the reactor, add 10 grams of 40% sodium hydroxide solution and 100 grams of pure water, pass oxygen for 5 minutes under normal pressure, stir and heat to 50°C, add 5 grams of cinnamaldehyde dropwise at a rate of 3 ml / min, oxygen flow rate of 8 L / h, stirring speed of 600 r / min, control the reaction temperature at 50°C, continue to pass oxygen and stir for 30 minutes after the addition is completed, let stand for 30 minutes, the catalyst settles to the bottom, filter the upper sodium cinnamate aqueous solution to separate it from the catalyst, and the catalyst can be reused 280 times;

[0083] (2) Pour the sodium cinnamate aqueous solution obtained in step (1) into another reaction flask, heat it to 65°C, add dilute sulfuric acid to adjust the pH value to 3-4, cool it to room temperature, filter after crystal precipitation, wash the solid with pure water more than 3 times, and when the pH value of the waste liquid reaches 5-6, dry it to obtain 5.58 grams of cinnamic acid with a content of more than 99% and a yield of 99.5%.

[0084] It is evident that the sponge silver obtained by this invention has excellent catalytic performance, achieving full recovery and utilization of silver elements in silver slag.

[0085] Example 2

[0086] Compared to Example 1, the difference is that the sample was directly soaked in 100 mL of hydrochloric acid for 2 hours. Sponge silver was prepared using the same method as described above, and its purity and catalytic performance were tested.

[0087] Test results: The purity of the sponge silver was 95.4%, the silver recovery rate was 95.2%, the cinnamic acid recovery rate was 92.4%, and the sponge silver catalyst could be reused 242 times.

[0088] Because multiple hydrochloric acid soaking treatments were not performed, impurities such as iron and copper in the silver slag were not fully removed, and the silver elements inside were not fully exposed. This resulted in incomplete reaction between the silver-containing filter residue and ammonia water, ultimately leading to a decrease in the purity and silver recovery rate of the resulting sponge silver, and a deterioration in catalytic performance.

[0089] Example 3

[0090] Compared to Example 1, the difference is that the sample was directly soaked in 105 mL of ammonia water for 4 hours. Sponge silver was prepared using the same method as described above, and its purity and catalytic performance were tested.

[0091] Test results: The purity of the sponge silver was 98.2%, the silver recovery rate was 96.8%, the cinnamic acid recovery rate was 97.4%, and the sponge silver catalyst could be reused 263 times.

[0092] Because the silver-containing filter residue was not subjected to multiple ammonia soaking treatments, the reaction with ammonia was incomplete, resulting in a decrease in the purity and silver recovery rate of the final sponge silver, and a deterioration in catalytic performance.

[0093] Example 4

[0094] Compared to Example 1, the difference is that hydrochloric acid soaking was not used. Sponge silver was prepared using the same method as described above, and its purity and catalytic performance were tested.

[0095] Test results: The purity of the sponge silver was 88.4%, the silver recovery rate was 87.2%, the cinnamic acid recovery rate was 88.1%, and the sponge silver catalyst could be reused 185 times.

[0096] Because the silver slag was not pre-treated with hydrochloric acid, the insoluble impurities that were not removed beforehand did not encapsulate the silver elements inside. As a result, the ammonia solution failed to react fully with the silver elements inside, and the purity and silver recovery rate of the resulting sponge silver decreased significantly, and the catalytic performance deteriorated significantly.

[0097] Example 5

[0098] Compared to Example 1, the difference is that 2.5 mL of a 60 wt% hydrazine hydrate solution was used as the reducing agent. Sponge silver was prepared using the same method as described above, and its purity and catalytic performance were tested.

[0099] Test results: The purity of the sponge silver was 96.5%, the silver recovery rate was 94.2%, the cinnamic acid recovery rate was 92.6%, and the sponge silver catalyst could be reused 208 times.

[0100] Hydrazine hydrate solution alone has poor reduction effect on silver chloride, resulting in a decrease in silver recovery rate. Furthermore, due to the low reactivity of hydrazine hydrate, the generated sponge silver cannot grow sufficiently, resulting in a low specific surface area of ​​the final sponge silver, a significant decrease in catalytic activity, and poorer inter-spontaneous bonding stability, which greatly reduces the number of times it can be reused.

[0101] Example 6

[0102] Compared to Example 1, the difference is that 2.5 mL of 60 wt% sodium borohydride solution was used as the reducing agent. Sponge silver was prepared using the same method as described above, and its purity and catalytic performance were tested.

[0103] Test results: The purity of the sponge silver was 97.2%, the silver recovery rate was 95.6%, the cinnamic acid recovery rate was 95.6%, and the sponge silver catalyst could be reused 232 times.

[0104] Sodium borohydride solution alone failed to achieve sufficient reduction of silver, resulting in decreased catalytic activity of the resulting sponge silver, poorer inter-sponge bonding stability, and a reduced number of reusable cycles.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A method for recovering silver from silver slag in gold smelting, characterized in that, Includes the following steps: (1) The silver slag from gold smelting was soaked in hydrochloric acid and filtered to obtain silver-containing filter residue; (2) Soak the silver-containing filter residue obtained in step (1) with ammonia water. Utilize the complexing effect of ammonia water on silver to convert the insoluble silver in the silver-containing filter residue into soluble silver ammonium complex ions, so that the silver enters the solution in the form of silver ammonium complex ions. Filter and separate from the insoluble residue to obtain silver-containing filtrate. (3) Add an appropriate amount of industrial sodium chloride to the silver-containing filtrate to adjust the pH value of the solution and promote the complete precipitation of silver chloride; (4) Filter and wash the silver chloride precipitate to remove impurities adhering to the silver chloride; (5) Dissolve the washed silver chloride in ammonia water, add a mixed solution of hydrazine hydrate and sodium borohydride for reduction, and obtain gray sponge silver, thus realizing the recovery of silver from silver slag in gold smelting. In step (1), the silver slag is soaked once with 50-100 mL of hydrochloric acid and filtered. The insoluble residue obtained by filtration is soaked a second time with 50-100 mL of hydrochloric acid and filtered. The resulting filter residue is used as silver-containing filter residue. In step (2), the silver-containing filter residue is soaked once with 50-100 mL of ammonia water and filtered. The insoluble residue obtained by filtration is soaked a second time with 50-100 mL of ammonia water and filtered. The filtrates obtained from the two soaking and filtration are combined as the silver-containing filtrate. In step (3), 15-25 ml of hydrochloric acid is added to adjust the pH of the solution so that pH < 12; In step (5), the amount of the mixed solution is 1-10 mL, the content of hydrazine hydrate in the mixed solution is 30-50 wt%, and the content of sodium borohydride is 10-30 wt%.

2. The method for recovering silver from silver slag in gold smelting according to claim 1, characterized in that, The silver slag from gold smelting is pretreated by drying it at 100-120℃ for 20-30 hours to remove impurities, obtaining a sample using a sealed sample preparation mechanism, and mixing it thoroughly. The sample is then tested for the content of gold, silver, and impurities, and the theoretical amount of reagents required is calculated based on the silver content.

3. The method for recovering silver from silver slag in gold smelting according to claim 1, characterized in that, In step (2), the amount of silver-containing filter residue is 1~5g, and the amount of ammonia water is 100-200mL; the ammonia water used is 1+2 ammonia water, that is, an ammonia water solution obtained by mixing one part by weight of concentrated ammonia water with two parts by weight of distilled water.

4. The method for recovering silver from silver slag in gold smelting according to claim 1, characterized in that, In step (3), the amount of sodium chloride used is 0.5~2g.

5. The method for recovering silver from gold smelting slag according to claim 1, characterized in that, In step (4), the silver chloride precipitate is washed with clean water 2 to 8 times.

6. The method for recovering silver from gold smelting slag according to claim 1, characterized in that, In step (5), the sponge silver is ashed at 600-700℃.

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