A method for selectively adsorbing and enriching gold ions from multi-metal elements

Abstract

The present application relates to waste metal material recycling technical field, disclose a kind of from multiple metal elements selectively adsorbed method of gold ion enrichment, including using pyridine triazine derivative as ligand and loaded in macroporous silicon-based material as adsorption material, from the acid aqueous solution containing gold ion and other metal ions and enrichment gold ion;The pyridine triazine derivative structure is as follows, wherein, R is C3-C5 straight-chain or branched alkyl.The present application adopts adsorption material, and Au (III) has high efficient selective enrichment effect, it is applicable to from the weak acid and strong acid gold-containing waste liquid containing multiple other metal elements adsorption and recovery precious metal gold element.Adsorption material itself has the characteristics of strong acid, strong alkali hydrolysis, simple preparation process, low cost, more conducive to in industrial production from gold-containing waste liquid efficiently recover precious metal gold element.

Description

Technical Field

[0001] This invention relates to the field of waste metal recycling technology, specifically to a method for selectively adsorbing and enriching gold ions from multiple metal elements. Background Technology

[0002] Besides its uses as currency and jewelry, gold has a wide range of applications in modern science and industry. Gold possesses extremely high corrosion resistance and chemical stability, excellent electrical and thermal conductivity, and its atomic nucleus has a large effective cross-section for capturing neutrons, resulting in near 100% infrared reflection. Gold alloys exhibit various catalytic properties; gold also has excellent workability, easily processed into ultra-thin gold foil, micron-sized gold wires, and gold powder. It is readily electroplated onto the surfaces of other metals, ceramics, and glass. Under certain pressure, gold can be easily fused and forged. Gold can also be used to create superconductors and organometallic compounds.

[0003] Because of its many unique chemical and physical properties, gold has the right to be widely used in the most important modern high-tech industries, such as electronics, communications, aerospace, chemical engineering, and medical technology, where it plays an irreplaceable role in areas such as industrial catalysis, hydrogen storage, and energy storage. However, the abundance of gold in the Earth's crust is extremely low. Currently, gold is mainly obtained from the utilization of natural mineral resources and the recycling of secondary resources from electronic products containing gold. But with the increasing depletion of gold resources, the sustainable use of gold resources is becoming increasingly difficult to achieve.

[0004] Gold is used in the manufacturing process of printed circuit boards from discarded mobile phones, televisions, and computers. Current waste electronic product processing often uses chemical methods such as extraction to remove the gold, but this is often very inefficient and involves the use of highly toxic chemicals such as cyanide, which harms health and pollutes the environment.

[0005] Chelated fibers refer to a class of multi-coordination polymers prepared by cross-linking reactions to incorporate various active groups onto a fibrous polymer matrix. They can utilize the chelating effect of different functional groups with different metal ions to obtain multi-component chelates, exhibiting high adsorption capacity and selective enrichment ability for metal ions. CN109610166A discloses a novel chelated fiber, its preparation method, and its application in the adsorption of Au in electronic waste. 3+ In its separation and enrichment application, the novel chelating fiber, based on polyacrylonitrile fiber and chelated with 5-aminobenzimidazolone as a ligand, is used to chelate the precious metal Au in electronic waste. 3+ It exhibits excellent selective adsorption. However, the preparation process of the polymer is cumbersome, the reaction time is long, and it can only achieve adsorption of gold in a weakly acidic environment (below 0.5 mol / L). The effect is often poor in high-concentration acidic environments.

[0006] If novel ligands with lower toxicity can be used to efficiently separate and purify gold resources from waste electronic products, enabling the recycling of gold resources, it will be of great significance in today's era of increasing emphasis on energy conservation and environmental protection, for expanding the sources of gold resources and developing green separation and recycling processes for gold resources.

[0007] Because these pyridine triazine ligands are resistant to strong acid hydrolysis, radiation, and have simple synthesis processes, they are currently mainly studied for their application in the extraction and separation of actinide metals. However, there are currently no reports in papers, patents, or other technical literature on the use of these ligands and related functional materials for the enrichment and separation of precious metals Au(III). Summary of the Invention

[0008] This invention addresses the problems in existing technologies, such as the difficulty in extracting gold from metal slag and waste electronic products, the low separation efficiency of separation extractants, and the difficulty in achieving gold enrichment and adsorption under high-concentration acid environments. It provides a solution-based method for highly efficient enrichment of gold ions, which can exhibit high selective enrichment of gold from a variety of metal elements and still show high separation efficiency under high-concentration acid environments. It is also non-toxic and environmentally friendly.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A method for selectively adsorbing and enriching gold ions from multi-metallic elements involves using a pyridine triazine derivative as a ligand supported on a macroporous silica-based material as the adsorbent to enrich gold ions from an acidic aqueous solution containing gold ions and other metal ions. The structure of the pyridine triazine derivative is as follows:

[0011]

[0012] Wherein, R is a C3-C5 straight-chain or branched alkyl group.

[0013] This invention employs a pyridine triazine soft ligand, which is resistant to hydrolysis by strong acids and bases, has a simple preparation process, and is low in cost, to composite with a silica carrier SiO2-P coated with a polymer material and having a macroporous structure, to obtain R-BTP@SiO2-P. This method selectively enriches and separates gold ions from weak and strong acidic aqueous solutions containing gold ions and polymetallic ions. Compared with traditional chemical methods such as solvent extraction, which are inefficient and involve the use of highly toxic chemicals such as cyanide, posing health risks and environmental pollution, the adsorption enrichment method in this patent has significant technical advantages.

[0014] Preferably, R is any one of propyl, n-butyl, or n-pentyl. More preferably, it is n-butyl, which, compared to ligands with other substituents, offers advantages such as higher gold enrichment efficiency and lower synthetic preparation cost.

[0015] The macroporous silica-based material is specifically the macroporous silica of the polymer, which is an organic polymer complex carrier containing porous silica carrier particles, prepared according to US Patent US6843921.

[0016] Preferably, the macroporous silicon-based material carrier uses SiO2 with a micron-sized pore structure as the carrier, which can load more pyridine derivative ligand materials. More preferably, SiO2-P (polymer) coated with a polymer material is selected, which makes the interaction between the carrier and the pyridine derivative ligand stronger and the material more stable.

[0017] The preparation process of the adsorbent material specifically includes: dissolving the pyridine triazine derivative in dichloromethane, adding macroporous silica-based material and stirring to mix, and then drying to obtain the adsorbent material.

[0018] Preferably, after adding the macroporous silicon-based material, the mixture is stirred at room temperature for 1-3 hours, and then stirred at 40-60°C for 2-4 hours. During this process, R-BTP will enter the pores of SiO2-P particles through capillary action and intermolecular interaction forces. After vacuum drying overnight, a brown powdery soft ligand macroporous silicon-based composite material R-BTP@SiO2-P is obtained.

[0019] The gold ions mentioned are trivalent and originate from gold-bearing slag or industrial waste electronic products. Recycling these resources has significant social and economic value.

[0020] The other metal ions include representative transition metals, alkaline earth metals, noble metals, Group VIII metals, and some lanthanide elements, such as one or more of Ca(II), Mg(II), Sr(II), Zn(II), Pb(II), Cd(II), Cu(II), Ru(III), Rh(III), La(III), Eu(III), Lu(III), Fe(III), Co(II), and Ni(II).

[0021] The adsorbent material in this invention has high selectivity but low enrichment capacity for multiple metal elements, thus effectively achieving the extraction and collection of gold.

[0022] Preferably, the other metal ions are one or more selected from Ca(II), Mg(II), Sr(II), Zn(II), Pb(II), Cd(II), Ru(III), La(III), Eu(III), Lu(III), Co(II), and Ni(II).

[0023] The mass ratio of the pyridine triazine derivative to the macroporous silicon-based material is 1:(2-5);

[0024] Alternatively, the loading of pyridine triazine derivatives in the macroporous silicon-based material is 15-35%.

[0025] Preferably, the mass ratio of the pyridine triazine derivative to the macroporous silica-based material is 1:3, that is, the loading of the pyridine triazine derivative in the macroporous silica-based material is 25%.

[0026] The acidic aqueous solution is an aqueous solution of hydrochloric acid, nitric acid, or sulfuric acid, wherein the concentration of hydrochloric acid is 0.001-4M, that is, the pH range is 1-3 and the acid concentration ranges from 0.2-4M.

[0027] Preferably, the pH of the acidic aqueous solution is 1-2, which results in higher gold enrichment efficiency.

[0028] Common gold adsorbent materials in existing technologies are often limited to pH values ​​below 2 and cannot withstand high-concentration acid environments. The adsorbent material of this invention can achieve highly selective enrichment of gold ions in both weak and strong acid environments. This is very beneficial for the recycling of gold-containing slag or industrial waste electronic products. It can effectively dissolve these wastes and allows for the direct selective enrichment and recovery of gold ions using the adsorbent material of this invention without dilution or with minimal dilution.

[0029] The gold ion concentration in the acidic aqueous solution is above 0.2 ppm, and the total concentration of other metal ions is less than 1000 times the gold ion concentration. In some embodiments, the gold ion concentration in the acidic aqueous solution is above 0.5 ppm, and the total concentration of multiple metal ions is less than 500 times the gold ion concentration, such as less than 400 times, less than 300 times, less than 200 times, or less than 100 times.

[0030] The enrichment time is above 30 min, and the enrichment temperature is 15-55℃. Preferably, the adsorption equilibrium time is above 60 min. The research results show that the composite material adsorbs metal ions quickly. After 60 min of adsorption, the adsorption of metal ions can reach adsorption equilibrium. Further preferred, the adsorption equilibrium time is 60-90 min.

[0031] The mass-to-volume ratio of the adsorbent material to the acidic aqueous solution is (10-100) mg:(5-30) mL. The adsorbent material of this invention exhibits advantages such as strong selective complexation with gold, and has broad application prospects in the separation and recovery of gold from industrial waste liquids, especially waste electronic products. The adsorption rate of gold ions is above 80%, such as above 85%, above 90%, above 92%, above 95%, above 96%, and above 98%.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) This invention utilizes R-BTP@SiO2-P macroporous silica-based soft ligand composite material for the efficient enrichment of Au(III), suitable for the adsorption and recovery of precious metal gold from weakly acidic and strongly acidic gold-containing waste liquids. Compared to traditional adsorbents that can only enrich gold ions in weakly acidic aqueous phases with a pH greater than 2, this invention can efficiently enrich gold ions in strongly acidic aqueous solutions such as molar-level hydrochloric acid.

[0034] (2) The R-BTP@SiO2-P macroporous silicon-based soft ligand composite material used in this invention exhibits very low adsorption capacity for precious metals other than gold, alkaline earth metals, transition metals, group VIII metals and lanthanides, which enables the method of this invention to efficiently and selectively separate gold from the aqueous phase of various metal ions, which is of great significance and has broad market prospects for the separate recovery of gold.

[0035] (3) The R-BTP@SiO2-P composite material used in this invention is obtained by physical compounding of a pyridine triazine soft ligand that is resistant to strong acid and strong alkali hydrolysis, has a simple preparation process and low cost, and a SiO2-P carrier with a macroporous structure that is resistant to strong acid corrosion. This makes it more conducive to the efficient recovery of precious metal gold from gold-containing waste liquid in industrial production. Attached Figure Description

[0036] Figure 1 The adsorption performance of R-BTP@SiO2-P on Au(III) under different contact time conditions in Example 1.

[0037] Figure 2 Example 2 illustrates the selective adsorption performance of Au(III) by R-BTP@SiO2-P under different acidity conditions.

[0038] Figure 3 Example 3 shows the adsorption performance of R-BTP@SiO2-P alone on Au(III) under different acidity conditions. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0040] The pyridine derivative ligands used in the following specific embodiments were prepared according to the synthetic method in Solvent Extraction & Ion Exchange, 1999, 17, 1155-1170. The dipropyl α-diketone derived from propylpyridine triazine in the original text was replaced with dibutyl α-diketone. The molecular structure of the resulting nBu-BTP is shown in the figure below:

[0041]

[0042] The preparation process of the adsorbent material nBu-BTP@SiO2-P is as follows: 1.02 g of nBu-BTP was placed in a 100.0 mL round-bottom flask and dissolved in approximately 30.0 mL of dichloromethane. Then, 2.0 g of activated SiO2-P was added. After stirring at room temperature for 120 min, the mixture was stirred at 45 °C for 180 min. During this process, R-BTP entered the pores of the SiO2-P particles through capillary action and intermolecular forces. The mixture was then vacuum dried overnight to obtain a brown powdery soft ligand macroporous silica-based composite. Composite materials R-BTP@SiO2-P.

[0043] The allocation coefficient K described below d The value is the ratio of the metal ion content adsorbed into the solid phase after adsorption equilibrium to the metal ion content in the aqueous phase at adsorption equilibrium (the metal ion content in the aqueous phase at adsorption equilibrium is determined by ICP-OES, and then the metal ion content in the solid phase at adsorption equilibrium is obtained by the difference method).

[0044]

[0045] In equation (1), C (b) Indicates the concentration of metal ions in the aqueous phase before adsorption; C (a) V represents the concentration of metal ions in the aqueous phase after adsorption equilibrium; V represents the volume of the aqueous metal ion solution in cm³. 3 ; m represents the dosage of adsorbent nBu-BTP@SiO2-P in g.

[0046] The adsorption rate E is the percentage of the target metal ions adsorbed during the adsorption process relative to the total amount of the adsorbed substance in the original aqueous phase, i.e.:

[0047] E = 100% × (C (b) -C (a) ) / C (b) (2)

[0048] In equation (2), C (a) This indicates the concentration of metal ions in the equilibrium aqueous phase after one adsorption cycle (the metal ion content in the equilibrium aqueous phase is obtained by ICP-OES detection); C (b)This indicates the concentration of metal ions in the aqueous phase before the first adsorption.

[0049] Example 1

[0050] Step 1, prepare the solid and aqueous phases: accurately weigh 10.0 mg nBu-BTP@SiO2-P into a series of 10.0 mL glass vials as the solid phase for the adsorption experiment; dissolve an appropriate amount of AuCl3·2H2O in hydrochloric acid aqueous solution and add a certain amount of NaOH standard solution to prepare an aqueous gold ion solution with pH 1-3 using a pH meter; add an appropriate amount of concentrated hydrochloric acid to obtain an aqueous phase with a hydrochloric acid concentration of 0.2 M to 4.0 M, and make the concentration of gold ions in the prepared aqueous phase approximately 10 ppm.

[0051] Step 2, Adsorption Experiment Procedure: Accurately weigh 10 mg nBu-BTP@SiO2-P into a series of 10.0 mL glass vials, then accurately measure 5.0 mL of the prepared aqueous solution containing gold ions with different hydrochloric acid concentrations into the glass vial and mix thoroughly with the solid adsorbent. Place the vial in a constant temperature shaking chamber at 298 K for the adsorption experiment.

[0052] After adsorption equilibrium was reached, the solid phase and aqueous phase were separated using a filter membrane. The concentration of gold ions in the aqueous phase was analyzed and measured to obtain the concentration of gold ions in the solid and aqueous phases before and after adsorption under different acidity conditions. The gold ion adsorption rate E% was calculated. The relevant results are shown in Table 1 and 2. Figure 1 .

[0053] Example 2

[0054] Using nBu-BTP@SiO2-P as the solid-phase adsorbent, and following the same method as in Example 1, 15 other interfering ions were added under different acidity conditions: alkaline earth metals Ca(II), Mg(II), Sr(II); transition metals Zn(II), Pb(II), Cd(II), Cu(II); noble metals Ru(III), Rh(III); rare earth metals La(III), Eu(III), Lu(III); and group 8 metals Fe(III), Co(II), Ni(II). The amount of each of the other metal ions added was approximately 10 ppm. The test temperature was 298 K, the adsorption time was 180 min, and the oscillation frequency was 200 rpm. The selective enrichment effect of nBu-BTP@SiO2-P on Au(III) under different hydrochloric acid concentrations is shown in Table 2. Figure 2 .

[0055] Example 3

[0056] Using nBu-BTP@SiO2-P as a solid-phase adsorbent, and following the same method as in Example 1, the adsorption and enrichment effect of nBu-BTP@SiO2-P on hydrochloric acid solution containing only Au(III) single element was tested under different adsorption time conditions at pH=1.

[0057] The adsorption efficiency E%, of nBu-BTP@SiO2-P for enriching gold ions varies with the following conditions: 1) hydrochloric acid concentration in the aqueous phase; 2) presence of interfering ions; and 3) different time conditions. Figure 1 , Figure 2 and Figure 3 As shown, the adsorption rate E% and partition coefficient D of Au(III) are shown in Table 1-3.

[0058] Table 1. Experimental results of Au(III) adsorption by nBu-BTP@SiO2-P under different hydrochloric acid concentrations.

[0059] Hydrochloric acid concentration (M) Au(III) adsorption rate (E%) <![CDATA[Au(III) distribution coefficient K d > 0.001 (pH=3) 87.88 3626.9 0.01 (pH=2) 90.07 4538.7 0.1 (pH=1) 93.11 6759.9 0.2 91.07 5099.5 0.5 88.52 3854.6 1.0 87.08 3370.0 2.0 85.58 2968.5 3.0 82.80 2406.6 4.0 78.55 1830.5

[0060] As can be seen from Table 1, the adsorbent used in this patent application has a high adsorption efficiency for Au(III) in the acidity range of 0.01 to 0.2 M hydrochloric acid concentration. Its adsorption rate for Au(III) is above 90%. When the hydrochloric acid concentration is as high as 3.0 M, its enrichment efficiency for Au(III) is above 80%, which is very suitable for enriching and recovering gold elements from aqueous solutions with high hydrochloric acid concentration.

[0061] Table 2. Adsorption results of the adsorption materials for Au(III) at different acidities under the condition of presence of interfering ions.

[0062] Hydrochloric acid concentration (M) Au(III) adsorption rate (E%) <![CDATA[Au(III) distribution coefficient K d > 0.001 (pH=3) 28.66 200.9 0.01 (pH=2) 64.45 906.5 0.1 (pH=1) 92.94 6585.8 0.2 91.07 5099.5 0.5 89.58 4296.2 1.0 88.07 3692.4 2.0 87.68 3557.8 3.0 85.94 3056.7 4.0 83.02 2445.0

[0063] As can be seen from Table 2, the nBu-BTP@SiO2-P adsorbent used in this invention application has a high selective adsorption efficiency for Au(III) under high acidity conditions. Its adsorption rate for Au(III) is above 80% in the acidity range of 0.1M-4.0M. Compared with traditional gold ion adsorbents that can only adsorb gold ions under low acidity, this adsorbent is very suitable for adsorbing and recovering gold elements from high-concentration hydrochloric acid polymetallic waste liquid.

[0064] Table 3. Experimental results of Au(III) adsorption by nBu-BTP@SiO2-P at different times under 0.1M acidity.

[0065]

[0066] As can be seen from Table 3, the nBu-BTP@SiO2-P adsorbent used in this patent application reached a basic equilibrium state for the adsorption of Au(III) under an adsorption time of approximately 90 min, with an extraction rate of over 90% for Au(III) and an enrichment efficiency of over 93% for Au(III) at 180 min. Therefore, this material exhibits a fast adsorption rate and high adsorption efficiency for gold, demonstrating excellent adsorption performance.

[0067] The above results indicate that the macroporous silica-based composite material nBu-BTP@SiO2-P, a type of pyridine triazine derivative, exhibits strong adsorption capacity and high selectivity for Au(III), making it a highly promising gold-based adsorbent.

Claims

1. A method for selectively adsorbing and enriching gold ions from polymetallic elements, characterized in that, include: A pyridine triazine derivative was used as a ligand loaded onto a macroporous silica-based material as an adsorbent to enrich gold ions from an acidic aqueous solution containing gold ions and other metal ions. The structure of the pyridine triazine derivative is as follows: Wherein, R is a C3-C5 straight-chain or branched alkyl group; The gold ions are trivalent and are derived from gold-containing slag or industrial waste electronic products. The acidic aqueous solution is an aqueous solution of hydrochloric acid with an acid concentration of 0.001-4M.

2. The method for selectively adsorbing and enriching gold ions from polymetallic elements according to claim 1, characterized in that, R is any one of propyl, n-butyl, or n-pentyl.

3. The method for selectively adsorbing and enriching gold ions from polymetallic elements according to claim 1, characterized in that, The other metal ions include one or more of Ca(II), Mg(II), Sr(II), Zn(II), Pb(II), Cd(II), Cu(II), Ru(III), Rh(III), La(III), Eu(III), Lu(III), Fe(III), Co(II), and Ni(II).

4. The method for selectively adsorbing and enriching gold ions from polymetallic elements according to claim 1, characterized in that, The mass ratio of the pyridine triazine derivative to the macroporous silicon-based material is 1:(2-5); Alternatively, the loading of pyridine triazine derivatives in the macroporous silicon-based material is 15-35%.

5. The method for selectively adsorbing and enriching gold ions from polymetallic elements according to claim 1, characterized in that, The gold ion concentration in the acidic aqueous solution is above 0.2 ppm, and the total concentration of other metal ions is less than 1000 times the gold ion concentration.

6. The method for selectively adsorbing and enriching gold ions from polymetallic elements according to claim 1, characterized in that, The enrichment time is more than 30 minutes, and the enrichment temperature is 15-55℃.

7. The method for selectively adsorbing and enriching gold ions from polymetallic elements according to claim 1, characterized in that, The mass-to-volume ratio of the adsorbent material to the acidic aqueous solution is (10-100) mg:(5-30) mL.

8. The method for selectively adsorbing and enriching gold ions from polymetallic elements according to claim 1, characterized in that, The preparation process of the adsorbent material specifically includes: dissolving the pyridine triazine derivative in dichloromethane, adding macroporous silica-based material and stirring to mix, and then drying to obtain the adsorbent material.

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