Application of covalent triazine backbone polymers in the recovery of gold (I) from thiosulfate solutions

Abstract

This invention discloses the application of a covalent triazine framework polymer in the recovery of gold (I) from thiosulfate solution, belonging to the field of precious metal recovery technology in hydrometallurgy. The method of this invention involves a one-step synthesis of a novel covalent triazine framework material with stable chemical properties via an amine-aldehyde condensation reaction of melamine and aldehyde compounds; and its direct application in the adsorption and recovery of [Au(S₂O₃)₂] from thiosulfate solution. 3‑ Complex ions. The materials prepared by the method described in this invention have advantages such as simple preparation process and stable performance, and can also recover gold (I) in single-system thiosulfate solutions and actual gold leaching systems; therefore, this invention provides a reference for the recovery of gold (I) from thiosulfate solutions.

Description

Technical Field

[0001] This invention relates to the application of covalent triazine backbone polymers in the recovery of gold (I) from thiosulfate solutions, belonging to the field of precious metal recovery technology in hydrometallurgy. Background Technology

[0002] With the large-scale global mining of gold resources, easily beneficiated gold ores are becoming increasingly scarce. Traditional cyanidation methods are ineffective at processing carbonaceous, arsenic, and copper-based gold ores, and cyanide is a highly toxic chemical reagent. Some regions in the world restrict the use of cyanide leaching for gold, which has spurred the development of non-cyanide gold extraction processes. Among these, the thiosulfate process, with its advantages of being non-toxic, low-cost, and effective in processing certain difficult-to-beneficiate gold ores, is considered the most likely green gold extraction technology to replace traditional cyanidation.

[0003] Although the thiosulfate process holds advantages in gold leaching, the recovery of gold (I) from the leachate remains a challenge; common adsorbent materials such as activated carbon and mesoporous silica gel are incompatible with [Au(S2O3)2]. 3- The weak affinity between complex ions prevents them from effectively recovering gold(I) from thiosulfate solutions, limiting the practical application of this technology. Therefore, developing a more efficient gold recovery method is of great significance for the practical application of gold extraction technology from thiosulfate. Summary of the Invention

[0004] The purpose of this invention is to provide the application of covalent triazine backbone polymers in the recovery of gold (I) from thiosulfate solutions; to achieve the recovery of [Au(S2O3)2] from thiosulfate solutions. 3- The purpose of complex ion separation and enrichment is to effectively recover gold (I) from thiosulfate solution using covalent triazine framework polymers, which have fast adsorption rates and high loading capacities.

[0005] The specific adsorption method is as follows: the covalent triazine backbone polymer is added to the gold (I)-containing thiosulfate solution and adsorption is carried out by mechanical stirring. The pH of the solution is adjusted to alkaline before the adsorbent is added.

[0006] Preferably, the preparation method of the covalent triazine backbone polymer of the present invention specifically includes the following steps:

[0007] (1) Add aldehyde compounds to a reaction vessel and place it in a water bath, then add melamine powder, stir to dissolve and mix evenly, and finally add curing agent, wherein the molar ratio of melamine to aldehyde compounds is 1:2 to 1:10.

[0008] (2) Under water bath heating conditions, the solid was refluxed and the reaction was completed. The solid was washed by deionized water multiple times and dried under vacuum to constant weight to obtain a polymer with a triazine skeleton.

[0009] Preferably, the aldehyde compound mentioned in step (1) of the present invention is one of formaldehyde, glyoxal, malondialdehyde, succinaldehyde, and glutaraldehyde.

[0010] Preferably, the curing agent used in step (1) of the present invention is m-phenylenediamine, ammonium chloride, zinc chloride or benzenesulfonic acid, and the mass ratio of the curing agent to melamine is 0.5 to 2.0.

[0011] Preferably, the reaction conditions in step (2) of the present invention are: heating at 30-90°C and magnetic stirring for 1-12 hours.

[0012] The covalent triazine backbone polymer of this invention achieves [Au(S2O3)2] through anion exchange. 3- The complex ions are rapidly adsorbed, and they contain a large number of adsorption sites with strong loading capacity.

[0013] The beneficial effects of this invention are as follows:

[0014] (1) The present invention uses a simple one-step synthesis method to induce an amine-aldehyde condensation reaction between melamine and aldehyde compounds to obtain a polymer material with stable chemical properties. This material can effectively recover gold (I) from thiosulfate solution.

[0015] (2) The method described in this invention is simple to operate, has a fast adsorption rate, and the resulting material is effective against [Au(S2O3)2]. 3- The recovery efficiency of complex ions is high. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0017] Example 1

[0018] A novel method for preparing a covalent triazine backbone polymer and its application, specifically including the following steps:

[0019] (1) Preparation process: Melamine and succinaldehyde solutions were added to a round-bottom flask at a molar ratio of 1:3 and placed in a water bath at a temperature of 60°C. Then, m-phenylenediamine was added, with the mass ratio of curing agent to melamine being 2.0. The mixture was magnetically stirred for 4 hours. The resulting solid was washed by multiple filtrations with deionized water and vacuum dried to constant weight to obtain the polymer material.

[0020] (2) Adsorption process: Prepare 100 mL of 20 mg / L [Au(S2O3)2]3- [Solution, pH value adjusted to 9 before adsorption; 0.3g of material obtained in step (1) was added, and mechanically stirred for 4h for adsorption; after the adsorption experiment, the sample was oxidized, dried and diluted to a fixed volume; finally, the gold concentration of the sample was analyzed, and the adsorption rate was measured to be 65% and the gold loading was 4.333kg / t.

[0021] Example 2

[0022] A novel method for preparing a covalent triazine backbone polymer and its application, specifically including the following steps:

[0023] (1) Preparation process: Melamine and malondialdehyde solution were added to a round bottom flask at a molar ratio of 1:7 and placed in a water bath at a temperature of 80°C. Then benzenesulfonic acid was added, wherein the mass ratio of curing agent to melamine was 1.75. The mixture was magnetically stirred for 2 hours. The resulting solid was washed by multiple filtrations with deionized water and vacuum dried to constant weight to obtain polymer material.

[0024] (2) Adsorption process: Prepare 100 mL of 50 mg / L [Au(S2O3)2] 3- [Solution, pH value adjusted to 8 before adsorption; 0.3g of material obtained in step (1) was added, and mechanically stirred for 4h for adsorption; after the adsorption experiment, the sample was oxidized, dried and diluted to a fixed volume; finally, the gold concentration of the sample was analyzed, and the adsorption rate was measured to be 52% and the gold loading was 8.667kg / t.

[0025] Example 3

[0026] A novel method for preparing a covalent triazine backbone polymer and its application, specifically including the following steps:

[0027] (1) Preparation process: Melamine and glyoxal solutions were added to a round-bottom flask at a molar ratio of 1:5 and placed in a water bath at a temperature of 30°C. Then m-phenylenediamine was added, with the mass ratio of curing agent to melamine being 0.5. The mixture was magnetically stirred for 12 hours. The resulting solid was washed by multiple filtrations with deionized water and dried under vacuum to constant weight to obtain the polymer material.

[0028] (2) Adsorption process: Prepare 100 mL of 20 mg / L [Au(S2O3)2] 3- The solution was prepared, and the pH value was adjusted to 10 before adsorption. 0.3g of the material obtained in step (1) was added and mechanically stirred for 4 hours for adsorption. After the adsorption experiment, the sample was oxidized, dried and diluted to a fixed volume. Finally, the gold concentration of the sample was analyzed, and the adsorption rate was found to be 69% and the gold loading was 4.6kg / t.

[0029] Example 4

[0030] A novel method for preparing a covalent triazine backbone polymer and its application, specifically including the following steps:

[0031] (1) Preparation process: Melamine and glutaraldehyde solutions were added to a round-bottom flask at a molar ratio of 1:8 and placed in a water bath at a temperature of 90°C. Ammonium chloride was then added, with the mass ratio of curing agent to melamine being 0.75. The mixture was magnetically stirred for 1 hour. The resulting solid was washed by multiple filtrations with deionized water and dried under vacuum to constant weight to obtain the polymer material.

[0032] (2) The material's effect on the actual gold ore leaching solution [Au(S2O3)2] 3- Adsorption of [Au(S2O3)2]: Taking a leaching solution of a high-sulfur, high-arsenic gold ore with a gold content of approximately 20.4 g / t after roasting as an example, the adsorption of [Au(S2O3)2] in the leaching solution... 3- The concentration of Cu was 5.8 mg / L. 2+ With a concentration of 5 mmol / L, an ethylenediamine (en) concentration of 10 mmol / L, and a pH of 9, 100 mL of the leachate was taken, and 1 g of the material obtained in step (1) was added. The mixture was mechanically stirred for 4 h for adsorption. After the adsorption experiment, the sample was subjected to oxidation, drying, and volume adjustment, and the gold concentration of the sample was finally analyzed. Through multi-stage adsorption, the material basically achieved complete adsorption of gold in the actual leachate.

[0033] Example 5

[0034] A novel method for preparing a covalent triazine backbone polymer and its application, specifically including the following steps:

[0035] (1) Preparation process: Melamine and formaldehyde solution were added to a round bottom flask at a molar ratio of 1:4 and placed in a water bath at a temperature of 50°C. Zinc chloride was then added, and the mass ratio of curing agent to melamine was 1.25. The mixture was magnetically stirred for 8 hours. The resulting solid was washed by multiple filtrations with deionized water and vacuum dried to constant weight to obtain the polymer material.

[0036] (2) The material's effect on the actual gold ore leaching solution [Au(S2O3)2] 3- Adsorption of [Au(S2O3)2]: Taking a gold oxide ore leaching solution with a gold content of approximately 10.28 g / t as an example, the adsorption of [Au(S2O3)2] in the leaching solution... 3- The concentration of Cu was 15.2 mg / L. 2+ Concentration of 5 mmol / L, NH3 / NH4 + With a concentration of 2 mol / L and a pH of 9, 100 mL of leachate was taken, and 1 g of the material obtained in step (1) was added. The material was mechanically stirred and adsorbed for 4 h. After the adsorption experiment, the sample was taken and subjected to oxidation, drying, and volume adjustment. Finally, the gold concentration of the sample was analyzed. After multi-stage adsorption, the material basically achieved complete adsorption of gold in the actual leachate.

Claims

1. Application of covalent triazine backbone polymers in the recovery of gold (I) from thiosulfate solutions; The preparation method of the covalent triazine backbone polymer specifically includes the following steps: (1) Add aldehyde compounds to the reaction vessel and place it in a water bath, then add melamine powder, stir to dissolve and mix evenly, and finally add curing agent, wherein the molar ratio of melamine to aldehyde compounds is 1:2~1:10; (2) Under water bath heating conditions, the solid was refluxed and the solid obtained after the reaction was completed was washed by deionized water multiple times and dried under vacuum to constant weight to obtain a polymer with a triazine skeleton. The curing agent used in step (1) is m-phenylenediamine, ammonium chloride, zinc chloride or benzenesulfonic acid, and the mass ratio of curing agent to melamine is 0.5 to 2.

0.

2. The application according to claim 1, characterized in that: The aldehyde compound mentioned in step (1) is one of formaldehyde, glyoxal, malondialdehyde, succinaldehyde, and glutaraldehyde.

3. The application according to claim 1, characterized in that: The reaction conditions in step (2) are: heating at 30 ~ 90℃ and magnetic stirring for 1 ~ 12 h.