A method for recovering gold from gold ion electrolysis tail liquid

Abstract

The present application relates to the field of precious metal recovery, and specifically discloses a method for recovering gold from gold ion electrolysis tail liquid; a method for recovering gold from gold ion electrolysis tail liquid, comprising the following specific steps: S1 ion exchange adsorption: after cleaning the mixed bed, soaking the ion exchange resin in sodium hydroxide solution, then loading it into the mixed bed and adding the gold tail liquid for ion exchange adsorption; S2 gold recovery: drying and carbonizing the ion exchange resin that has adsorbed the gold tail liquid to obtain a gold-containing compound, mixing and dissolving the gold-containing compound with aqua regia, using hydrochloric acid for denitrification to obtain gold aqua regia, vacuum filtering and washing, and then using anhydrous sodium sulfite for reduction to obtain reduced gold powder, which is then dried to obtain the gold powder; the ion exchange resin raw materials include cation exchange resin and carboxymethyl chitosan; the present application can enhance the adsorption capacity and adsorption rate of the ion exchange resin through the synergistic effect of various processes, thereby improving the gold recovery effect.

Description

Technical Field

[0001] The present application relates to the field of precious metal recovery, and in particular to a method for recovering gold from gold ion electrolysis tail liquid. Background Art

[0002] Currently, there are many methods for gold purification both domestically and internationally, including extraction, hydrochlorination, and electrolysis. Current extraction agents primarily target gold in precious liquids, requiring extraction and stripping, a lengthy process. The extractants can become passivated over time, requiring regular activation, increasing production costs. The hydrochlorination method requires significant investment and a lengthy process, making it suitable for larger mines. Electrolysis offers the advantages of lower costs and higher gold purity after purification.

[0003] However, the gold electrolysis process produces waste tail liquid, which still contains a certain amount of gold and other valuable metals. Direct discharge of this waste liquid not only results in a huge waste of resources but also causes serious environmental pollution. Re-electrolysis of the tail liquid has limited effect on gold purification, and the electrolysis cycle is also long. Summary of the Invention

[0004] In order to improve the recovery effect of gold in electrolysis tail liquid, the present application provides a method for recovering gold from gold ion electrolysis tail liquid.

[0005] The present application provides a method for recovering gold from gold ion electrolysis tail liquid, which adopts the following technical solution:

[0006] A method for recovering gold from gold ion electrolysis tail liquid comprises the following specific steps:

[0007] S1 ion exchange adsorption: After cleaning the mixed bed, soak the ion exchange resin with sodium hydroxide solution, then load it into the mixed bed and add gold tail liquid for ion exchange adsorption;

[0008] S2 gold recovery: drying and carbonizing the ion exchange resin that adsorbed the gold tail liquid to obtain a gold-containing compound, mixing and dissolving the gold-containing compound with aqua regia, denitrifying with hydrochloric acid to obtain gold aqua regia, vacuum filtering and washing, and then reducing with anhydrous sodium sulfite to obtain reduced gold powder, which is then dried to obtain gold powder;

[0009] The ion exchange resin raw materials include cation exchange resin and carboxymethyl chitosan. The cation exchange resin includes the following raw materials in parts by weight: 20-30 parts of quaternary ammonium cation exchange resin, 10-20 parts of protein, 5-8 parts of crosslinking agent, 5-8 parts of acrylonitrile, 5-8 parts of water, and 3-5 parts of ammonium persulfate.

[0010] By adopting the above technical solution, pre-immersing the ion exchange resin in sodium hydroxide solution can reduce residual impurities in the ion exchange resin, promote the ion exchange resin to effectively adsorb gold ions in the gold tail liquid, improve the ion exchange adsorption effect of gold ions, and enhance the gold recovery efficiency. Anhydrous sodium sulfite can reduce the gold ions in the aqua regia, effectively reducing the gold powder in the aqua regia and improving the purity of the recovered gold. Through the synergistic effect of various processes, the gold content in the gold electrolysis tail liquid can be reduced to less than 3ppm, thereby improving the gold recovery efficiency.

[0011] Combining carboxymethyl chitosan with a cation exchange resin can enhance the adsorption capacity and rate of the ion exchange resin, improving gold recovery. Chitosan molecules contain both hydroxyl and amino groups, which have a strong chelating ability for gold ions. The introduction of carboxyl groups into carboxymethyl chitosan can enhance the chelating ability of the ion exchange resin, accelerating the efficiency and amount of gold adsorption by the ion exchange resin, and enhancing gold recovery.

[0012] By utilizing the quaternary ammonium groups of quaternary ammonium cation exchange resins to exchange with gold ions and adsorb gold ions from gold tail liquid, gold recovery efficiency can be improved. Proteins, through hydrophilic groups such as carboxyl, amino, and amide groups, have a strong affinity for water molecules and can form coordination bonds with gold ions, thereby improving the stability and adsorption capacity of the cation exchange resin and increasing its biocompatibility. Through the crosslinking reaction between the crosslinking agent, sodium persulfate, acrylonitrile, and quaternary ammonium cation exchange resin, a crosslinked resin network structure can be formed within the cation exchange resin system, reducing swelling or shrinkage of the ion exchange resin during use and improving its dimensional stability and adsorption performance.

[0013] Preferably, after the gold tail liquid is subjected to ion exchange adsorption, when the gold content in the adsorbed tail liquid is detected to be ≤2.3 ppm, the ion exchange resin is taken out, filtered and dried, carbonized at 580-620° C., and cooled to obtain a gold-containing compound.

[0014] Preferably, the mass ratio of the gold-containing compound to aqua regia is 1:(2.5-3.5).

[0015] Preferably, the usage amount of the anhydrous sodium sulfite is 0.8-1.2 times the weight of gold in the gold tail solution.

[0016] Preferably, the preparation method of the cation exchange resin comprises the following specific steps: pre-mixing a quaternary ammonium cation exchange resin and acrylonitrile to form a mixed solution, adjusting the pH of the mixed solution to neutral, then adding a cross-linking agent, protein, and ammonium persulfate for mixed reaction, vacuum drying, and crushing to obtain the cation exchange resin.

[0017] Preferably, the mass ratio of the cation exchange resin to carboxymethyl chitosan is 1:(0.8-1.5).

[0018] Preferably, the carboxymethyl chitosan is pre-crosslinked with glutaraldehyde and glutamic acid, and the mass ratio of the carboxymethyl chitosan, glutaraldehyde and glutamic acid is 1:(2-3):(1-1.5).

[0019] By adopting the above technical solution, carboxymethyl chitosan is cross-linked with glutaraldehyde, and the aldehyde group of glutaraldehyde can be used to form a Schiff base structure with the free amino group in the carboxymethyl chitosan, thereby enhancing the acid and alkali resistance of the carboxymethyl chitosan, thereby improving the strength and stability of the ion exchange resin, reducing the dissolution of the ion exchange resin, making the spatial structure of the ion exchange resin more stable, and more rapidly adsorbing complex metal ions, thereby increasing the adsorption capacity and adsorption rate of the ion exchange resin for gold ions.

[0020] Glutaraldehyde is cross-linked with carboxymethyl chitosan to form a network polymer of linear carboxymethyl chitosan. At the same time, glutaraldehyde can also use the aldehyde group to react with the amino group of glutamic acid to generate a Schiff base structure, connecting the free α and γ carboxyl groups on glutamic acid to the carboxymethyl chitosan cross-linked product, increasing the active groups on the carboxymethyl chitosan cross-linked product, enhancing the complex adsorption capacity of carboxymethyl chitosan with gold ions, enhancing the gold ion adsorption capacity of the ion exchange resin, and improving the gold recovery efficiency.

[0021] Preferably, the preparation method of the ion exchange resin comprises the following specific steps:

[0022] S1: After dissolving carboxymethyl chitosan to form a carboxymethyl chitosan solution, the pH of the carboxymethyl chitosan solution is adjusted to 4-5, and then glutamate is added and mixed and dissolved, and then glutaraldehyde is added, and the mixture is heated and stirred to react to obtain a carboxymethyl chitosan cross-linked complex; S2: A cation exchange resin and the carboxymethyl chitosan cross-linked complex are mixed, loaded into a mold, heated and pressurized to set the shape, and demolded after cooling to obtain an ion exchange resin.

[0023] Preferably, in step S1 of the method for preparing the ion exchange resin, the heating temperature is 30-50°C.

[0024] In summary, this application has the following beneficial effects:

[0025] 1. Because the present invention pre-treats the ion exchange resin, it can reduce the residual impurities in the ion exchange resin and improve the ion exchange adsorption effect of gold ions. The use of carboxymethyl chitosan and cation exchange resin in the ion exchange resin raw material can enhance the adsorption capacity and adsorption rate of the ion exchange resin and improve the gold recovery effect. On the other hand, the addition of protein to the cation exchange resin raw material improves the stability and biocompatibility of the cation exchange resin. Through the cross-linking reaction between the cross-linking agent, sodium persulfate, acrylonitrile and quaternary ammonium cation exchange resin, a resin network structure can be formed in the cation exchange resin, thereby improving the dimensional stability and adsorption performance of the cation exchange resin.

[0026] 2. In this application, glutaraldehyde, glutamic acid and carboxymethyl chitosan are cross-linked, and the aldehyde group of glutaraldehyde is reacted with the free amino group and the amino group of glutamic acid in carboxymethyl chitosan to form a network of carboxymethyl chitosan cross-linked products, which makes the ion exchange resin space structure more stable, more rapidly adsorbs complexed metal ions, and improves the adsorption and recovery effect of gold ions. DETAILED DESCRIPTION

[0027] The present application is further described in detail below with reference to the embodiments.

[0028] All raw materials in the examples are commercially available.

[0029] The gold content in the gold ion electrolysis tail solution used in this embodiment is 0.35 g / L.

[0030] Carboxymethyl chitosan was purchased from Dalian Xindie Chitosan Company, with a substitution degree of 81%.

[0031] Glutamic acid is L-glutamic acid.

[0032] Preparation Example of Cation Exchange Resin

[0033] Preparation Example 1

[0034] The cation exchange resin comprises the following raw materials by weight: 25 kg of quaternary ammonium cation exchange resin, 15 kg of protein, 7 kg of cross-linking agent, 7 kg of acrylonitrile, 7 kg of water, and 4 kg of ammonium persulfate, wherein the quaternary ammonium cation exchange resin is Amberlyst A-26 and the cross-linking agent is polyvinyl alcohol.

[0035] The preparation method of the cation exchange resin comprises the following specific steps:

[0036] Quaternary ammonium cation exchange resin and acrylonitrile are mixed in advance to form a mixed solution, sodium hydroxide is used to adjust the pH of the mixed solution to neutral, and then a cross-linking agent, protein and ammonium persulfate are added for mixed reaction, vacuum dried and crushed to obtain the cation exchange resin.

[0037] Preparation Example 2

[0038] The difference between Preparation Example 2 and Preparation Example 1 is that the amount of quaternary ammonium cation exchange resin used in the cation exchange resin raw material is 20 kg, the amount of protein used is 10 kg, the amount of cross-linking agent used is 5 kg, the amount of acrylonitrile used is 8 kg, the amount of water used is 5 kg, and the amount of ammonium persulfate used is 3 kg.

[0039] Preparation Example 3

[0040] Preparation Example 3 differs from Preparation Example 1 in that the amount of quaternary ammonium cation exchange resin used in the cation exchange resin raw material is 30 kg, the amount of protein used is 20 kg, the amount of cross-linking agent used is 8 kg, the amount of acrylonitrile used is 5 kg, the amount of water used is 8 kg, and the amount of ammonium persulfate used is 5 kg.

[0041] Preparation Example 4

[0042] Preparation Example 4 differs from Preparation Example 1 in that no protein is used as the raw material for the cation exchange resin.

[0043] Preparation Example 5

[0044] The difference between Preparation Example 5 and Preparation Example 1 is that the cation exchange resin is a quaternary ammonium cation exchange resin, wherein the quaternary ammonium cation exchange resin is Amberlyst A-26 resin.

[0045] Example

[0046] Example 1

[0047] This embodiment provides a method for recovering gold from gold ion electrolysis tail liquid, comprising the following specific steps:

[0048] S1: Mixing a cation exchange resin and carboxymethyl chitosan in a mass ratio of 1:1.2, wherein the cation exchange resin is obtained from Preparation Example 1, placing the mixture into a mold, heating the mixture to 200° C., shaping the mixture under 25 MPa, and then cooling and demolding the mixture to obtain the ion exchange resin.

[0049] S2: After the mixed bed is cleaned with a 10% sodium hydroxide aqueous solution by mass, the ion exchange resin is soaked in a 4% sodium hydroxide aqueous solution by mass for 40 minutes, and then the ion exchange resin is filled into the mixed bed. Then, the gold tail liquid is added to the ion exchange column filled with the ion exchange resin at a flow rate of 50m / h to perform ion exchange adsorption.

[0050] S3: After 12 hours of ion exchange adsorption of the gold tail liquid, the gold content in the adsorption tail liquid is determined. When the gold content in the adsorption tail liquid is detected to be 2.3 ppm, the ion exchange resin is removed, filtered and dried, and then carbonized at 600°C for 4 hours and cooled to obtain a gold-containing compound; the gold-containing compound is mixed and dissolved with aqua regia, the mass ratio of the gold-containing compound to aqua regia is 1:3, and the mixture is heated to 40°C and dissolved for 2 hours. Then, hydrochloric acid is slowly added at a flow rate of 30 m / h for denitrification until the gold-containing compound is completely dissolved in the aqua regia. Then, heating and adding hydrochloric acid are stopped to obtain aqua regia.

[0051] S4: Vacuum filter and wash the aqua regia until the pH value of the filtrate is neutral, then slowly add anhydrous sodium sulfite to the filtered aqua regia, with the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid being 1:1, to obtain reduced gold powder, which is then filtered, washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0052] Example 2

[0053] This embodiment provides a method for recovering gold from gold ion electrolysis tail liquid, comprising the following specific steps:

[0054] S1: Mixing a cation exchange resin and carboxymethyl chitosan in a mass ratio of 1:0.8, wherein the cation exchange resin is obtained from Preparation Example 1, placing the mixture into a mold, heating the mixture to 200° C., shaping the mixture under 25 MPa, and then cooling and demolding the mixture to obtain the ion exchange resin.

[0055] S2: After the mixed bed is cleaned with a 10% sodium hydroxide aqueous solution by mass, the ion exchange resin is soaked in a 4% sodium hydroxide aqueous solution by mass for 40 minutes, and then the ion exchange resin is filled into the mixed bed. Then, the gold tail liquid is added to the ion exchange column filled with the ion exchange resin at a flow rate of 50m / h to perform ion exchange adsorption.

[0056] S3: After 12 hours of ion exchange adsorption of the gold tail liquid, the gold content in the adsorbed tail liquid is determined. When the gold content in the adsorbed tail liquid is detected to be 2.3 ppm, the ion exchange resin is removed, filtered and dried, and then carbonized at 600°C for 4 hours and cooled to obtain a gold-containing compound; the gold-containing compound is mixed and dissolved with aqua regia, the mass ratio of the gold-containing compound to aqua regia being 1:2.5, and heated to 40°C for dissolution for 2 hours, and then hydrochloric acid is slowly added at a flow rate of 30 m / h for denitrification until the gold-containing compound is completely dissolved in the aqua regia, and then heating and hydrochloric acid addition are stopped to obtain aqua regia.

[0057] S4: Vacuum filter and wash the aqua regia until the pH value of the filtrate is neutral, then slowly add anhydrous sodium sulfite to the filtered aqua regia, with the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid being 1:0.8, to obtain reduced gold powder, which is then filtered, washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0058] Example 3

[0059] This embodiment provides a method for recovering gold from gold ion electrolysis tail liquid, comprising the following specific steps:

[0060] S1: Mixing a cation exchange resin and carboxymethyl chitosan in a mass ratio of 1:1.5, wherein the cation exchange resin is obtained from Preparation Example 1, placing the mixture into a mold, heating the mixture to 200° C., shaping the mixture under 25 MPa, and then cooling and demolding the mixture to obtain the ion exchange resin.

[0061] S2: After the mixed bed is cleaned with a 10% sodium hydroxide aqueous solution by mass, the ion exchange resin is soaked in a 4% sodium hydroxide aqueous solution by mass for 40 minutes, and then the ion exchange resin is filled into the mixed bed. Then, the gold tail liquid is added to the ion exchange column filled with the ion exchange resin at a flow rate of 50m / h to perform ion exchange adsorption.

[0062] S3: After 12 hours of ion exchange adsorption of the gold tail liquid, the gold content in the adsorbed tail liquid is determined. When the gold content in the adsorbed tail liquid is detected to be 2.3 ppm, the ion exchange resin is removed, filtered and dried, and then carbonized at 600°C for 4 hours and cooled to obtain a gold-containing compound; the gold-containing compound is mixed and dissolved with aqua regia, the mass ratio of the gold-containing compound to aqua regia being 1:3.5, and heated to 40°C for dissolution for 2 hours, and then hydrochloric acid is slowly added at a flow rate of 30 m / h for denitrification until the gold-containing compound is completely dissolved in the aqua regia, and then heating and hydrochloric acid addition are stopped to obtain aqua regia.

[0063] S4: Vacuum filter and wash the aqua regia until the pH value of the filtrate is neutral, then slowly add anhydrous sodium sulfite to the filtered aqua regia, with the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid being 1:1.2, to obtain reduced gold powder, which is then filtered, washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0064] Example 4

[0065] The difference between Example 4 and Example 1 is that the cation exchange resin in the method for recovering gold from gold ion electrolysis tail liquid comes from Preparation Example 2.

[0066] Example 5

[0067] The difference between Example 5 and Example 1 is that the cation exchange resin in the method for recovering gold from gold ion electrolysis tail liquid comes from Preparation Example 3.

[0068] Example 6

[0069] The difference between Example 6 and Example 1 is that in the method for recovering gold from the gold ion electrolysis tail liquid, the carboxymethyl chitosan is cross-linked with glutaraldehyde.

[0070] A method for recovering gold from gold ion electrolysis tail liquid comprises the following specific steps:

[0071] S1: Carboxymethyl chitosan and glutaraldehyde are mixed and stirred uniformly, the mass ratio of carboxymethyl chitosan to glutaraldehyde is 1:2.5, the temperature is raised to 40°C, stirred and reacted for 1 hour, filtered, refluxed with acetone, and dried to obtain a carboxymethyl chitosan cross-linked product; a cation exchange resin and the carboxymethyl chitosan cross-linked product are mixed, the mass ratio of the cation exchange resin to the carboxymethyl chitosan cross-linked product is 1:1.2, and the cation exchange resin is obtained from Preparation Example 1. The mixture is loaded into a mold, heated to 200°C, shaped at 25 MPa, and then cooled and demolded to obtain an ion exchange resin.

[0072] S2: After the mixed bed is cleaned with a 10% sodium hydroxide aqueous solution by mass, the ion exchange resin is soaked in a 4% sodium hydroxide aqueous solution by mass for 40 minutes, and then the ion exchange resin is filled into the mixed bed. Then, the gold tail liquid is added to the ion exchange column filled with the ion exchange resin at a flow rate of 50m / h to perform ion exchange adsorption.

[0073] S3: After 12 hours of ion exchange adsorption of the gold tail liquid, the gold content in the adsorption tail liquid is determined. When the gold content in the adsorption tail liquid is detected to be 2.3 ppm, the ion exchange resin is removed, filtered and dried, and then carbonized at 600°C for 4 hours and cooled to obtain a gold-containing compound; the gold-containing compound is mixed and dissolved with aqua regia, the mass ratio of the gold-containing compound to aqua regia is 1:3, and the mixture is heated to 40°C and dissolved for 2 hours. Then, hydrochloric acid is slowly added at a flow rate of 30 m / h for denitrification until the gold-containing compound is completely dissolved in the aqua regia. Then, heating and adding hydrochloric acid are stopped to obtain aqua regia.

[0074] S4: Vacuum filter and wash the aqua regia until the pH value of the filtrate is neutral, then slowly add anhydrous sodium sulfite to the filtered aqua regia, with the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid being 1:1, to obtain reduced gold powder, which is then filtered, washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0075] Example 7

[0076] The difference between Example 7 and Example 6 is that in the method for recovering gold from the gold ion electrolysis tail liquid, the carboxymethyl chitosan is cross-linked with glutaraldehyde and glutamic acid.

[0077] A method for recovering gold from gold ion electrolysis tail liquid comprises the following specific steps:

[0078] S1: dissolving carboxymethyl chitosan in a 2% by mass aqueous acetic acid solution to form a carboxymethyl chitosan solution, adjusting the pH of the carboxymethyl chitosan solution to 4 using a 2% by mass aqueous acetic acid solution, heating to 40°C, adding glutamic acid to dissolve, and then adding glutaraldehyde to mix and stir evenly, the mass ratio of carboxymethyl chitosan to glutaraldehyde and glutamic acid being 1:2.5:1.2, heating to 45°C, stirring to react for 1 hour, filtering, refluxing with acetone, and drying to obtain a carboxymethyl chitosan cross-linked product; mixing a cation exchange resin with the carboxymethyl chitosan cross-linked product, the mass ratio of the cation exchange resin to the carboxymethyl chitosan cross-linked product being 1:1.2, the cation exchange resin being derived from Preparation Example 1, loading into a mold, heating to 200°C, shaping at 25 MPa, and then cooling and demolding to obtain an ion exchange resin.

[0079] S2: After the mixed bed is cleaned with a 10% sodium hydroxide aqueous solution by mass, the ion exchange resin is soaked in a 4% sodium hydroxide aqueous solution by mass for 40 minutes, and then the ion exchange resin is filled into the mixed bed. Then, the gold tail liquid is added to the ion exchange column filled with the ion exchange resin at a flow rate of 50m / h to perform ion exchange adsorption.

[0080] S3: After 12 hours of ion exchange adsorption of the gold tail liquid, the gold content in the adsorption tail liquid is determined. When the gold content in the adsorption tail liquid is detected to be 2.3 ppm, the ion exchange resin is removed, filtered and dried, and then carbonized at 600°C for 4 hours and cooled to obtain a gold-containing compound; the gold-containing compound is mixed and dissolved with aqua regia, the mass ratio of the gold-containing compound to aqua regia is 1:3, and the mixture is heated to 40°C and dissolved for 2 hours. Then, hydrochloric acid is slowly added at a flow rate of 30 m / h for denitrification until the gold-containing compound is completely dissolved in the aqua regia. Then, heating and adding hydrochloric acid are stopped to obtain aqua regia.

[0081] S4: Vacuum filter and wash the aqua regia until the pH value of the filtrate is neutral, then slowly add anhydrous sodium sulfite to the filtered aqua regia, with the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid being 1:1, to obtain reduced gold powder, which is then filtered, washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0082] Comparative Example

[0083] Comparative Example 1

[0084] The difference between Comparative Example 1 and Example 1 is that the cation exchange resin in the method for recovering gold from gold ion electrolysis tail liquid comes from Preparation Example 4.

[0085] Comparative Example 2

[0086] The difference between Comparative Example 2 and Example 1 is that the cation exchange resin in the method for recovering gold from gold ion electrolysis tail liquid comes from Preparation Example 5.

[0087] Comparative Example 3

[0088] The difference between Comparative Example 3 and Example 1 is that carboxymethyl chitosan is not used in the method for recovering gold from gold ion electrolysis tail liquid.

[0089] A method for recovering gold from gold ion electrolysis tail liquid comprises the following specific steps:

[0090] S1: After the mixed bed is cleaned with a 10% sodium hydroxide aqueous solution by mass, the cation exchange resin is soaked in a 4% sodium hydroxide aqueous solution by mass for 40 minutes. The cation exchange resin is obtained from Preparation Example 1. The cation exchange resin is then filled into the mixed bed. Then, the gold tail liquid is added to the ion exchange column filled with the cation exchange resin at a flow rate of 50m / h for ion exchange adsorption.

[0091] S2: After 12 hours of ion exchange adsorption of the gold tail liquid, the gold content in the adsorbed tail liquid is determined. When the gold content in the adsorbed tail liquid is detected to be 2.3 ppm, the ion exchange resin is removed, filtered and dried, and then carbonized at 600°C for 4 hours and cooled to obtain a gold-containing compound; the gold-containing compound is mixed and dissolved with aqua regia in a mass ratio of 1:3, heated to 40°C and dissolved for 2 hours, and then hydrochloric acid is slowly added at a flow rate of 30 m / h for denitrification until the gold-containing compound is completely dissolved in the aqua regia. Then, heating and adding hydrochloric acid are stopped to obtain aqua regia.

[0092] S3: Vacuum filter and wash the aqua regia until the pH value of the filtrate is neutral, then slowly add anhydrous sodium sulfite to the filtered aqua regia, with the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid being 1:1, to obtain reduced gold powder, which is then filtered, washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0093] Comparative Example 4

[0094] The difference between Comparative Example 4 and Example 1 is that an equal amount of chitosan is used instead of carboxymethyl chitosan in the method for recovering gold from the gold ion electrolysis tail liquid.

[0095] Performance testing

[0096] According to the gold recovery method for gold ion electrolysis tail liquid provided in Examples 1-7 and Comparative Examples 1-4 of the present application, the extracted gold powder was weighed, and the recovery rate and purity of the gold were measured and tested. At the same time, the ion exchange resin prepared in the gold ion electrolysis tail liquid recovery method was adsorbed on the gold tail liquid for 4 hours. The adsorbed gold tail liquid was then taken, and the change in gold content in the gold tail liquid was measured. The adsorption rate of the ion exchange resin was tested. The specific test results are shown in Table 1.

[0097] Table 1: Test results data table

[0098]

[0099]

[0100] It can be seen from the performance test results that the method for recovering gold from the gold ion electrolysis tail liquid adopted in this application has a high recovery efficiency. From the test data results of gold recovery in Examples 1-5, it can be seen that the method for recovering gold from the gold ion electrolysis tail liquid adopted in Example 1 has better adsorption effect and recovery effect on gold ions.

[0101] As can be known by embodiment 6-7, carboxymethyl chitosan is cross-linked through glutaraldehyde in the embodiment, and carboxymethyl chitosan is double cross-linked through glutaraldehyde, glutamic acid in embodiment 7.As can be known by the detection data result, embodiment 7 reclaims the effect of gold better, and the ion exchange resin that embodiment 7 adopts is higher to the adsorption rate of gold ion simultaneously.Further explanation, by the aldehyde group of glutaraldehyde and free amino group reaction in carboxymethyl chitosan, then glutamic acid carboxyl group is connected in the carboxymethyl chitosan cross-linked product, stable reticulated carboxymethyl chitosan cross-linked product can be formed, strengthen the complexing adsorption capacity of carboxymethyl chitosan and gold ion, strengthen the gold ion adsorption capacity of ion exchange resin.

[0102] By comparing Comparative Examples 1-2 with Example 1, it can be seen that in Comparative Example 1, no protein is used in the cation exchange resin raw material, and in Comparative Example 2, a conventional quaternary ammonium cation exchange resin is used as the cation exchange resin. As can be seen from the test data results, the adsorption capacity and efficiency of the prepared ion exchange resin are significantly reduced. It is further demonstrated that the adsorption capacity of conventional cation exchange resins is limited and the efficiency for gold ions is low, thereby extending the recovery cycle of gold ions and increasing production costs.

[0103] By comparing Comparative Examples 3-4 with Example 1, it can be seen that in Comparative Example 3, the ion exchange resin does not use carboxymethyl chitosan, and in Comparative Example 4, the ion exchange resin raw material uses an equal amount of chitosan instead of carboxymethyl chitosan. As can be seen from the test data results, the adsorption capacity and efficiency of the prepared ion exchange resin are both reduced. It is further proved that the present application can effectively increase the coordination bonds on the surface of the ion exchange resin by cross-linking with protein and acrylonitrile, and then compounding with carboxymethyl chitosan, thereby enhancing the gold ion adsorption capacity of the ion exchange resin and improving the gold recovery efficiency.

[0104] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for recovering gold from gold ion electrolysis tail liquid, characterized in that: The specific steps include: S1 ion exchange adsorption: After cleaning the mixed bed, soak the ion exchange resin with sodium hydroxide solution, then load it into the mixed bed and add gold tail liquid for ion exchange adsorption; S2 gold recovery: drying and carbonizing the ion exchange resin that adsorbed the gold tail liquid to obtain a gold-containing compound, mixing and dissolving the gold-containing compound with aqua regia, denitrifying with hydrochloric acid to obtain gold aqua regia, vacuum filtering and washing, and then reducing with anhydrous sodium sulfite to obtain reduced gold powder, which is then dried to obtain gold powder; The raw materials of the ion exchange resin include cation exchange resin and carboxymethyl chitosan. The cation exchange resin includes the following raw materials in parts by weight: 20-30 parts of quaternary ammonium cation exchange resin, 10-20 parts of protein, 5-8 parts of crosslinking agent, 5-8 parts of acrylonitrile, 5-8 parts of water, and 3-5 parts of ammonium persulfate.

2. The gold ion electrolysis tail liquid gold recovery method according to claim 1, wherein After the gold tail liquid is subjected to ion exchange adsorption, when the gold content in the adsorbed tail liquid is detected to be ≤2.3 ppm, the ion exchange resin is taken out, filtered and dried, carbonized at 580-620° C., and cooled to obtain a gold-containing compound.

3. The gold recovery method of gold ion electrolysis tail liquid according to claim 1, wherein The mass ratio of the gold-containing compound to aqua regia is 1:(2.5-3.5).

4. The gold recovery method of gold ion electrolysis tail liquid according to claim 1, wherein The usage amount of the anhydrous sodium sulfite is 0.8-1.2 times of the weight of gold in the gold tail solution.

5. The method for recovering gold from gold ion electrolysis tail liquid according to claim 1, wherein The preparation method of the cation exchange resin comprises the following specific steps: pre-mixing a quaternary ammonium cation exchange resin and acrylonitrile to form a mixed solution, adjusting the pH of the mixed solution to be neutral, then adding a cross-linking agent, protein, and ammonium persulfate for mixed reaction, vacuum drying, and crushing to obtain the cation exchange resin.

6. The method for recovering gold from gold ion electrolysis tail liquid according to claim 5, wherein: The mass ratio of the cation exchange resin to carboxymethyl chitosan is 1:(0.8-1.5).

7. The method for recovering gold from gold ion electrolysis tail liquid according to claim 6, wherein: The carboxymethyl chitosan is cross-linked with glutaraldehyde and glutamic acid in advance, and the mass ratio of the carboxymethyl chitosan, glutaraldehyde and glutamic acid is 1: (2-3): (1-1.5).

8. The method for recovering gold from gold ion electrolysis tail liquid according to claim 7, wherein: The preparation method of the ion exchange resin comprises the following specific steps: S1: dissolving carboxymethyl chitosan to form a carboxymethyl chitosan solution, adjusting the pH of the carboxymethyl chitosan solution to 4-5, then adding glutamic acid and mixing and dissolving, then adding glutaraldehyde, heating and stirring to react, to obtain a carboxymethyl chitosan cross-linked complex; S2: Mixing the cation exchange resin and the carboxymethyl chitosan cross-linked complex, placing the mixture into a mold, heating and pressurizing the mixture to set the shape, and demolding the mixture after cooling to obtain the ion exchange resin.

9. The method for recovering gold from gold ion electrolysis tail liquid according to claim 8, wherein In step S1 of the method for preparing the ion exchange resin, the heating temperature is 30-50°C.

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