Method for recovering gold from gold ion electrolysis tail liquid

Abstract

The invention relates to the field of precious metal recovery, and particularly discloses a method for recovering gold from gold ion electrolysis tail liquid. A method for recycling gold from gold ion electrolysis tail liquid comprises the following specific steps that S1, ion exchange adsorption is conducted, specifically, after a mixed bed is cleaned, ion exchange resin is soaked with a sodium hydroxide solution and then loaded into the mixed bed, and then the gold ion electrolysis tail liquid is added for ion exchange adsorption; the ion exchange resin adsorbing the gold tail liquid is dried and carbonized to obtain a gold-containing compound, the gold-containing compound and aqua regia are mixed and dissolved, hydrochloric acid is used for denitration to obtain gold aqua regia, vacuum filtering and washing are conducted, then anhydrous sodium sulfite is used for reduction to obtain reduced gold powder, and the gold powder is obtained after drying; the ion exchange resin raw materials comprise cation exchange resin and carboxymethyl chitosan; through the synergistic effect of all the processes, the adsorption capacity and the adsorption rate of the ion exchange resin can be enhanced, and the gold recovery effect is improved.

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] At present, there are many methods for gold purification at home and abroad, mainly extraction, water chlorine method, electrolysis method, etc. The current extracting agent is mainly for gold in precious liquid, which requires extraction and stripping, and the process is long. The extracting agent will be passivated after long-term use, and the extracting agent needs to be activated regularly, which increases production costs. The water chlorine method has a large investment and a long process flow, and is suitable for use in large-scale mines. The electrolysis method has the advantages of low cost 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 will not only cause a huge waste of resources, but also cause serious pollution to the environment. Reusing the tail liquid for electrolysis has limited effect on gold purification, and the electrolysis cycle is relatively 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: A method for recovering gold from gold ion electrolysis tail liquid comprises the following specific steps: 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 adsorbs 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 aqua regia gold, 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 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.

[0006] By adopting the above technical solution, the ion exchange resin is soaked in sodium hydroxide solution in advance, which can reduce the impurity residue in the ion exchange resin, promote the ion exchange resin to effectively adsorb the gold ions in the gold tail liquid, improve the ion exchange adsorption effect of the gold ions, and improve the gold recovery effect. Anhydrous sodium sulfite can reduce the gold ions in the gold aqua regia, can effectively reduce the gold powder in the gold aqua regia, and improve the purity of the recovered gold. Through the synergistic effect of each process, the gold content in the gold electrolysis tail liquid can be reduced to less than 3ppm, and the gold recovery effect can be improved.

[0007] Compounding carboxymethyl chitosan with cation exchange resin can enhance the adsorption capacity and adsorption rate of ion exchange resin and improve the gold recovery effect. Chitosan molecules contain both hydroxyl groups and amino groups, which have strong chelating ability for gold ions. At the same time, the introduction of carboxyl groups into carboxymethyl chitosan can enhance the chelating ability of ion exchange resins to gold ions, accelerate the adsorption efficiency and adsorption amount of ion exchange resins to gold, and enhance the gold recovery effect.

[0008] By utilizing the quaternary ammonium group of the quaternary ammonium cation exchange resin to exchange with gold ions and adsorb the gold ions in the gold tail liquid, the gold recovery efficiency can be improved. Proteins can have a strong affinity with water molecules through hydrophilic groups such as carboxyl, amino, and amide groups, and can form coordination bonds with gold ions, thereby improving the stability and adsorption capacity of the cation exchange resin and increasing the biocompatibility of the cation exchange resin. Through the cross-linking reaction between the cross-linking agent, sodium persulfate, acrylonitrile and the quaternary ammonium cation exchange resin, a cross-linked resin network structure can be formed in the cation exchange resin system, reducing the expansion or contraction of the ion exchange resin during use, and improving the dimensional stability and adsorption performance of the cation exchange resin.

[0009] 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 ≤2.3ppm, the ion exchange resin is taken out, filtered and dried, carbonized at 580-620°C, and cooled to obtain a gold-containing compound.

[0010] Preferably, the mass ratio of the gold-containing compound to aqua regia is 1:(2.5-3.5).

[0011] Preferably, the usage amount of the anhydrous sodium sulfite is 0.8-1.2 times of the weight of gold in the gold tail liquid.

[0012] 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 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.

[0013] Preferably, the mass ratio of the cation exchange resin to carboxymethyl chitosan is 1:(0.8-1.5).

[0014] Preferably, 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).

[0015] By adopting the above technical scheme, 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 amount and adsorption rate of the ion exchange resin for gold ions.

[0016] 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, and connect the free α and γ carboxyl groups on glutamic acid to the carboxymethyl chitosan cross-linked product, increase the active groups on the carboxymethyl chitosan cross-linked product, enhance the complex adsorption capacity of carboxymethyl chitosan and gold ions, enhance the gold ion adsorption capacity of ion exchange resin, and improve the gold recovery efficiency.

[0017] Preferably, the method for preparing 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 to mix and dissolve, and then adding glutaraldehyde, heating and stirring to react, to obtain a carboxymethyl chitosan cross-linked complex; S2: mixing a cation exchange resin with the carboxymethyl chitosan cross-linked complex, loading it into a mold, heating and pressurizing to shape it, and demolding it after cooling to obtain an ion exchange resin.

[0018] Preferably, in step S1 of the method for preparing the ion exchange resin, the heating temperature is 30-50°C.

[0019] In summary, this application has the following beneficial effects: 1. Since the present application pre-treats the ion exchange resin in advance, the impurity residues in the ion exchange resin can be reduced, and the ion exchange adsorption effect of gold ions can be improved. 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 of 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.

[0020] 2. In the present application, glutaraldehyde, glutamic acid and carboxymethyl chitosan are cross-linked, and the aldehyde group of glutaraldehyde is used to react with the free amino group in carboxymethyl chitosan and the amino group of glutamic acid to form a network carboxymethyl chitosan cross-linked product, which makes the spatial structure of the ion exchange resin more stable, and more rapidly adsorbs complex metal ions, thereby improving the adsorption and recovery effect of gold ions. DETAILED DESCRIPTION

[0021] The present application is further described in detail below with reference to the embodiments.

[0022] All raw materials in the examples are commercially available.

[0023] The gold content in the gold ion electrolysis tail solution used in this embodiment is 0.35 g / L.

[0024] Carboxymethyl chitosan was purchased from Dalian Xindie Chitosan Company, with a substitution degree of 81%.

[0025] Glutamic acid is L-glutamic acid.

[0026] Preparation example of cation exchange resin Preparation Example 1 The cation exchange resin comprises the following raw materials in parts 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.

[0027] The preparation method of the cation exchange resin comprises the following specific steps: The quaternary ammonium cation exchange resin and acrylonitrile are mixed in advance to form a mixed solution, the pH of the mixed solution is adjusted to be neutral using sodium hydroxide, 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.

[0028] Preparation Example 2 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.

[0029] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is 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.

[0030] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that no protein is used as the raw material of the cation exchange resin.

[0031] Preparation Example 5 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. Example

[0032] Example 1 This embodiment provides a method for recovering gold from gold ion electrolysis tail liquid, comprising the following specific steps: S1: Mixing a cation exchange resin and carboxymethyl chitosan in a mass ratio of 1:1.2, wherein the cation exchange resin is from Preparation Example 1, loading the mixture into a mold, heating the mixture to 200° C., shaping the mixture at 25 MPa, and then cooling and demolding the mixture to obtain an ion exchange resin.

[0033] S2: After the mixed bed is cleaned with a sodium hydroxide aqueous solution having a mass fraction of 10%, the ion exchange resin is soaked in a sodium hydroxide aqueous solution having a mass fraction of 4% for 40 minutes, and then the ion exchange resin is filled into the mixed bed, and 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.

[0034] 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 taken out, 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, and heating and hydrochloric acid addition are stopped to obtain aqua regia.

[0035] 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, the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid is 1:1, and obtain reduced gold powder, which is then filtered and washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0036] Example 2 This embodiment provides a method for recovering gold from gold ion electrolysis tail liquid, comprising the following specific steps: S1: Mixing a cation exchange resin and carboxymethyl chitosan in a mass ratio of 1:0.8, wherein the cation exchange resin is from Preparation Example 1, loading the mixture into a mold, heating the mixture to 200° C., shaping the mixture at 25 MPa, and then cooling and demolding the mixture to obtain an ion exchange resin.

[0037] S2: After the mixed bed is cleaned with a sodium hydroxide aqueous solution having a mass fraction of 10%, the ion exchange resin is soaked in a sodium hydroxide aqueous solution having a mass fraction of 4% for 40 minutes, and then the ion exchange resin is filled into the mixed bed, and 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.

[0038] 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 taken out, 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 1:2.5, 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, and then heating and hydrochloric acid addition are stopped to obtain aqua regia.

[0039] 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, the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid is 1:0.8, and the reduced gold powder is obtained, which is then filtered and washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain the gold powder.

[0040] Example 3 This embodiment provides a method for recovering gold from gold ion electrolysis tail liquid, comprising the following specific steps: S1: Mixing a cation exchange resin and carboxymethyl chitosan in a mass ratio of 1:1.5, wherein the cation exchange resin is from Preparation Example 1, loading the mixture into a mold, heating the mixture to 200° C., shaping the mixture at 25 MPa, and then cooling and demolding the mixture to obtain an ion exchange resin.

[0041] S2: After the mixed bed is cleaned with a sodium hydroxide aqueous solution having a mass fraction of 10%, the ion exchange resin is soaked in a sodium hydroxide aqueous solution having a mass fraction of 4% for 40 minutes, and then the ion exchange resin is filled into the mixed bed, and 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.

[0042] 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 taken out, 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 1:3.5, 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, and heating and hydrochloric acid addition are stopped to obtain aqua regia.

[0043] 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, the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid is 1:1.2, and the reduced gold powder is obtained, which is then filtered and washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain the gold powder.

[0044] Example 4 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.

[0045] Example 5 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.

[0046] Example 6 The difference between Example 6 and Example 1 is that in the method for recovering gold from gold ion electrolysis tail liquid, carboxymethyl chitosan is cross-linked with glutaraldehyde.

[0047] A method for recovering gold from gold ion electrolysis tail liquid comprises the following specific steps: S1: Mix carboxymethyl chitosan and glutaraldehyde in a mass ratio of 1:2.5, heat to 40°C, stir for 1 hour, filter and reflux with acetone, and dry to obtain a carboxymethyl chitosan cross-linked product; mix a cation exchange resin with the carboxymethyl chitosan cross-linked product in a mass ratio of 1:1.2, the cation exchange resin is derived from Preparation Example 1, put into a mold, heat to 200°C, shape at 25MPa, and then cool and demold to obtain an ion exchange resin.

[0048] S2: After the mixed bed is cleaned with a sodium hydroxide aqueous solution having a mass fraction of 10%, the ion exchange resin is soaked in a sodium hydroxide aqueous solution having a mass fraction of 4% for 40 minutes, and then the ion exchange resin is filled into the mixed bed, and 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.

[0049] 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 taken out, 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, and heating and hydrochloric acid addition are stopped to obtain aqua regia.

[0050] 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, the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid is 1:1, and obtain reduced gold powder, which is then filtered and washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0051] Example 7 The difference between Example 7 and Example 6 is that in the method for recovering gold from gold ion electrolysis tail liquid, carboxymethyl chitosan is cross-linked with glutaraldehyde and glutamic acid.

[0052] A method for recovering gold from gold ion electrolysis tail liquid comprises the following specific steps: S1: dissolving carboxymethyl chitosan in an acetic acid aqueous solution with a mass fraction of 2% to form a carboxymethyl chitosan solution, adjusting the pH value of the carboxymethyl chitosan solution to 4 with an acetic acid aqueous solution with a mass fraction of 2%, 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 and refluxing with acetone, and drying to obtain a carboxymethyl chitosan crosslink; mixing a cation exchange resin with the carboxymethyl chitosan crosslink, the mass ratio of the cation exchange resin to the carboxymethyl chitosan crosslink being 1:1.2, the cation exchange resin being derived from Preparation Example 1, loading into a mold, heating to 200°C, shaping at 25MPa, and then cooling and demolding to obtain an ion exchange resin.

[0053] S2: After the mixed bed is cleaned with a sodium hydroxide aqueous solution having a mass fraction of 10%, the ion exchange resin is soaked in a sodium hydroxide aqueous solution having a mass fraction of 4% for 40 minutes, and then the ion exchange resin is filled into the mixed bed, and 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.

[0054] 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 taken out, 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, and heating and hydrochloric acid addition are stopped to obtain aqua regia.

[0055] 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, the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid is 1:1, and obtain reduced gold powder, which is then filtered and washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain gold powder.

[0056] Comparative Example Comparative Example 1 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.

[0057] Comparative Example 2 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.

[0058] Comparative Example 3 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.

[0059] A method for recovering gold from gold ion electrolysis tail liquid comprises the following specific steps: S1: After the mixed bed is cleaned with a sodium hydroxide aqueous solution having a mass fraction of 10%, the cation exchange resin is soaked in a sodium hydroxide aqueous solution having a mass fraction of 4% 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, gold tail liquid is added to the ion exchange column loaded with the cation exchange resin at a flow rate of 50 m / h to perform ion exchange adsorption.

[0060] S2: 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 taken out, 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, and heating and hydrochloric acid addition are stopped to obtain aqua regia.

[0061] 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, the weight ratio of anhydrous sodium sulfite to gold in the gold tail liquid is 1:1, and the reduced gold powder is obtained, which is then filtered and washed, dried at 120°C for 4 hours, and cooled to room temperature to obtain the gold powder.

[0062] Comparative Example 4 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 gold ion electrolysis tail liquid.

[0063] Performance testing According to the gold recovery method of gold ion electrolysis tail liquid provided in Examples 1-7 and Comparative Examples 1-4 of the present application, the extracted gold powder is weighed, and the recovery rate and purity of gold are measured for testing. At the same time, after the ion exchange resin prepared in the gold ion electrolysis tail liquid recovery method adsorbs the gold tail liquid for 4 hours, the adsorbed gold tail liquid is taken, the change in the gold content of the gold tail liquid is measured, and the adsorption rate of the ion exchange resin is detected. The specific test results are shown in Table 1.

[0064] Table 1: Test results data table It can be seen from the performance test results that the method for recovering gold from the tail liquid of gold ion electrolysis adopted in the present 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 tail liquid of gold ion electrolysis adopted in Example 1 has better adsorption effect and recovery effect on gold ions.

[0065] It can be known by Examples 6-7 that carboxymethyl chitosan in the examples is cross-linked by glutaraldehyde, and carboxymethyl chitosan in Example 7 is double cross-linked by glutaraldehyde and glutamic acid. As can be seen from the test data results, the effect of gold recovery in Example 7 is better, and the adsorption rate of gold ions by the ion exchange resin adopted in Example 7 is higher. Further explanation, by the aldehyde group of glutaraldehyde and free amino group in carboxymethyl chitosan, glutamic acid carboxyl group is connected in the carboxymethyl chitosan cross-linked product, a stable network of carboxymethyl chitosan cross-linked product can be formed, the complexing adsorption capacity of carboxymethyl chitosan and gold ions is enhanced, and the gold ion adsorption capacity of the ion exchange resin is enhanced.

[0066] 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, the cation exchange resin uses a conventional quaternary ammonium cation exchange resin. From the test data results, it can be seen that the adsorption capacity and efficiency of the prepared ion exchange resin are significantly reduced. It is further proved 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.

[0067] By comparing Comparative Examples 3-4 with Example 1, it can be seen that the ion exchange resin in Comparative Example 3 does not use carboxymethyl chitosan, and the ion exchange resin raw material in Comparative Example 4 uses an equal amount of chitosan instead of carboxymethyl chitosan. It can be seen from the test data results that the adsorption capacity and efficiency of the prepared ion exchange resin will be reduced. It is further proved that the present application can effectively increase the coordination bonds on the surface of the ion exchange resin, enhance the gold ion adsorption capacity of the ion exchange resin, and improve the gold recovery efficiency by cross-linking the quaternary ammonium cation exchange resin with protein and acrylonitrile and then compounding with carboxymethyl chitosan.

[0068] 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 modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

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 adsorbs 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 aqua regia gold, 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 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 method for recovering gold from gold ion electrolysis tail liquid 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 method for recovering gold from 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 method for recovering gold from gold ion electrolysis tail liquid according to claim 1, characterized in that: The usage amount of the anhydrous sodium sulfite is 0.8-1.2 times of the weight of gold in the gold tail liquid.

5. The method for recovering gold from gold ion electrolysis tail liquid according to claim 1, characterized in that: The preparation method of the cation exchange resin comprises the following specific steps: pre-mixing 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, characterized in that: 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, characterized in that: 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, characterized in that: 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 to mix and dissolve, then adding glutaraldehyde, heating and stirring to react, and obtaining a carboxymethyl chitosan cross-linked complex; S2: Mix the cation exchange resin and the carboxymethyl chitosan cross-linked complex, put them into a mold, heat and pressurize them to shape them, and demold them after cooling to obtain the ion exchange resin.

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

Images