Method for efficiently recovering metal iridium from waste iridium and waste materials

Abstract

The invention provides a method for efficiently recovering metal iridium from waste iridium and waste materials, and belongs to the technical field of precious metal recovery. Comprising the following steps: (1) stripping a titanium substrate by adopting high-pressure water jet or ultrasonic vibration; (2) adding the titanium substrate obtained by stripping into mixed acid, carrying out gradient heating for dissolving, filtering, and reserving filtrate for later use; (3) adding a tributyl phosphate / kerosene system into the filtrate, extracting and separating the tributyl phosphate / kerosene system, and adding diluted hydrochloric acid for back extraction and separation to obtain an iridium extract; and (4) adding a purifying agent into the iridium extraction liquid, carrying out ultrasonic purification, separating the purifying agent, adding solid ammonium chloride into the filtrate, precipitating, filtering, washing the solid with an ammonium chloride solution, drying, and calcining to obtain an iridium oxide product. The method comprises the following steps: preferentially extracting iridium from a medium by adopting tributyl phosphate (the partition ratio is gt; 100), a purifying agent is added into the solution, and impurities such as Fe, Al and Cu ions are deeply removed.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of precious metal recovery, in particular to a method for efficiently recovering metallic iridium from waste iridium waste. BACKGROUND

[0002] Iridium (Ir) is a scarce platinum group metal, and is used as a core material for anode coating in the electrolytic industry (such as chlor-alkali and hydrogen production by electrolysis of water). Due to the difficulty in peeling the coating of the titanium-based waste anode, the recovery rate of precious metals is low (less than 80% in the traditional process), and efficient recovery technology is urgently needed. High-purity iridium compounds (such as IrO2) are key raw materials for preparing new anodes, and the purity needs to be greater than or equal to 99.95%.

[0003] The global annual production of iridium is only about 7 tons, and the recovery of high-purity iridium compounds through recovery technology can alleviate the supply pressure. In addition, the amount of iridium in waste anodes is 0.5-5%, and the recovery cost is reduced by 30-50% compared with primary ores. In addition, the traditional hydrometallurgy produces a large amount of acid-containing and heavy metal-containing waste liquid, and therefore, a better green and advanced recovery process needs to be developed. SUMMARY

[0004] The purpose of the present application is to provide a method for efficiently recovering metallic iridium from waste iridium waste. The titanium substrate is peeled off by high-pressure water jet or ultrasonic vibration-acid dissolution synergistic process, acid etching of the titanium substrate is avoided, the titanium substrate is kept intact (breakage rate <5%), the mixed acid system (such as HCl-HNO3 gradient heating) is optimized, the iridium ruthenium oxide is dissolved (dissolution rate >98%), the dissolution of titanium is inhibited (<0.1%), the tributyl phosphate (TBP) is used to preferentially extract iridium from the medium (distribution ratio >100), the purifying agent is added to the solution to deeply remove impurities such as Fe, Al and Cu ions (the purity is increased to 99.9%), and the alkali liquor absorbs the tail gas Cl2 and NOx to meet the GB16297 emission standard.

[0005] The technical scheme of the present application is as follows:

[0006] The present application provides a method for efficiently recovering metallic iridium from waste iridium waste, comprising the following steps:

[0007] (1) The titanium substrate is peeled off by high-pressure water jet or ultrasonic vibration;

[0008] (2) The peeled titanium substrate is added into a mixed acid, gradient heating is performed for dissolution, filtration is performed, and the filtrate is reserved;

[0009] (3) Tributyl phosphate / kerosene system is added into the filtrate, extraction is performed, the tributyl phosphate / kerosene system is separated, dilute hydrochloric acid is added for reverse extraction, separation is performed, and iridium extraction liquid is obtained;

[0010] (4) adding a purifying agent into the iridium extraction liquid, purifying under ultrasonic, separating the purifying agent, washing the purifying agent with EDTA solution and deionized water in sequence, drying, repeating the use, adding solid ammonium chloride into the filtrate to precipitate, filtering, washing the solid with ammonium chloride solution, drying, calcining, obtaining the iridium oxide product, purifying the tail gas by absorbing in lye, reaching the GB16297 emission standard.

[0011] As a further improvement of the present application, the pressure of the high-pressure water jet is 180-220 MPa, and the power of the ultrasonic vibration is 1500-2500 W, and the time is 10-30 min.

[0012] As a further improvement of the present application, the mixed acid is a mixture of hydrochloric acid and nitric acid, the concentration of the hydrochloric acid is 5-10 wt%, and the concentration of the nitric acid is 8-12 wt%, and the gradient temperature is 60-70 DEG C for 10-30 min, and 85-95 DEG C for 20-40 min.

[0013] As a further improvement of the present application, the content of the tributyl phosphate in the tributyl phosphate / kerosene system is 20-40 wt%, and the concentration of the dilute hydrochloric acid is 5-10 wt%.

[0014] As a further improvement of the present application, the adding amount of the purifying agent in the iridium extraction liquid is 2-3 wt%, the power of the ultrasonic is 500-1000 W, the time is 20-40 min, the calcining temperature is 200-240 DEG C, and the time is 1-3 h, and the lye is NaOH or KOH solution with a concentration of 10-20 wt%.

[0015] As a further improvement of the present application, the preparation method of the purifying agent is as follows:

[0016] S1. Preparation of the shrunken mesoporous silica nanosphere: mixing citric acid and a pore former into water, adding tetraethyl orthosilicate, adjusting the pH value of the solution, stirring and reacting, standing and aging, heating and crystallizing, centrifuging, washing, drying, and calcining to obtain the shrunken mesoporous silica nanosphere;

[0017] S2. Modification: adding the shrunken mesoporous silica nanosphere into ethanol, adding a composite silane coupling agent, heating and stirring to react, centrifuging, washing, and drying to obtain the modified nanosphere;

[0018] S3. Preparation of the nanocage: adding the modified nanosphere into dichloromethane, adding tris(4-benzaldehyde)amine, stirring at room temperature to react, and obtaining the nanocage modified nanosphere;

[0019] S4. Preparation of the purification agent: glutamic acid and aspartic acid are added to water, N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl) carbodiimide are added, stirring is activated, nanocage modified nanospheres are added, stirring reaction is carried out, centrifugation is carried out, washing is carried out, drying is carried out, and the purification agent is prepared.

[0020] As a further improvement of the application, the mass ratio of the citric acid, the pore-forming agent and the tetraethyl orthosilicate in step S1 is 0.3-0.5:1-1.2:5-7, the pore-forming agent is hexadecyl trimethyl ammonium chloride or hexadecyl trimethyl ammonium bromide, the pH value of the adjusting solution is 5-6, the stirring reaction time is 10-20 min, the standing aging time is 20-24 h, and the heating crystallization temperature is 95-100℃, and the time is 20-24 h.

[0021] As a further improvement of the application, the mass ratio of the shrinking mesoporous silica nanospheres and the composite silane coupling agent in step S2 is 10:2-3, the composite silane coupling agent includes a diamino silane coupling agent and a silane coupling agent with a mercapto group, the mass ratio is 5-7:2-3, the diamino silane coupling agent is KH602 or KH792, the silane coupling agent with a mercapto group is KH580 or KH590, and the heating stirring reaction temperature is 40-50℃, and the time is 2-4 h.

[0022] As a further improvement of the application, the mass ratio of the modified nanospheres and tris(4-benzaldehyde) amine in step S3 is 10:0.5-1, and the room temperature stirring reaction time is 1-3 h.

[0023] As a further improvement of the application, the mass ratio of the glutamic acid, aspartic acid, N-hydroxysuccinimide, 1-ethyl-(3-dimethylaminopropyl) carbodiimide and nanocage modified nanospheres in step S4 is 2-3:1-2:2-3:2-3:10, and the stirring reaction time is 10-15 h.

[0024] The application has the following beneficial effects:

[0025] The application uses a high-pressure water jet or ultrasonic vibration-acid dissolution synergistic process to strip the titanium substrate, avoids acid etching of the titanium substrate, optimizes a mixed acid system (such as an HCl-HNO3 gradient heating), dissolves iridium ruthenium oxide (dissolution rate >98%), inhibits titanium dissolution (<0.1%), uses tributyl phosphate (TBP) to preferentially extract iridium from the medium (partition ratio >100), adds a purification agent to the solution, and deeply removes impurities such as Fe, Al and Cu ions (purity is improved to 99.9%), and alkaline liquor absorbs tail gas Cl2 and NOx, reaching the GB16297 emission standard.

[0026] The solution obtained by dissolving waste iridium waste contains impurities such as Cu, Fe, Al, etc. 2+ / Fe 3+ Tends to combine with oxygen / nitrogen / sulfur coordination groups (such as -COOH, -NH2, -SH), Al 3+ Prefer carboxylic acid groups (-COOH), while iridium ions are more easily coordinated with phosphorus / phosphine ligands or rigid aromatic rings. 2+ (0.073nm), Fe 3+ (0.064nm), Al 3+ The ionic radius of the ions (0.0535nm) is smaller than that of the iridium ion (0.086nm), and the hydrated ionic radius (0.4-0.485nm) is significantly smaller than that of the iridium ion (>0.9nm).

[0027] The present invention prepares shrinkage mesoporous silica nanospheres during the preparation of the purifying agent. Hexadecyltrimethylammonium chloride is used as a porogen and citric acid is used as a template. Citric acid plays a key role in guiding the formation of the pore structure during the preparation of the mesoporous silica. Citric acid can form a specific molecular arrangement structure in the precursor solution of silica. The citric acid molecules have a certain shape and size. When it is mixed with a silica precursor (such as tetraethyl orthosilicate), under suitable conditions, the citric acid molecules will guide the silica precursor molecules to assemble around it. When the solvent evaporates, the silica precursor begins to further aggregate and assemble around the template. At the same time, the template will also undergo a certain degree of rearrangement due to the reduction of the solvent. This rearrangement will cause the structure of the pores to shrink. The initially formed pores may be large, but under the continuous action of solvent evaporation, the pores will gradually become smaller. Due to the size and shape limitations of the citric acid template and the synergistic effect of intermolecular interactions, the size of the pores will eventually shrink to the sub-nanometer range of 0.6-0.8nm, thereby achieving a confinement effect and being able to adsorb metal ions such as copper ions and iron ions with small radius, while iridium ions with large radius cannot enter the pores and are repelled outside.

[0028] The surface of the prepared shrinkage mesoporous silica nanospheres is modified by a composite silane coupling agent, including a silane coupling agent with a diamino group and a mercapto group. The diamino group structure enables it to react with tri(4-benzaldehyde)amine to form an imine bond by a Schiff base reaction, further forming a nano cage structure. The diameter of the cage structure is similar to that of Cu. 2+ 、Fe 3+ 、Al 3+ The ionic radius structure of the two is similar, and the N center can also provide lone pair electrons, thereby improving the complexing ability, so that it can further better fix the impurity metal ions instead of fixing the iridium ions. The thiol structure can also complex and fix Cu well. 2+ 、Fe 3+ 、Al3+ .

[0029] In addition, the free and unreacted amino groups can be coupled with glutamic acid and aspartic acid to form a carboxyl layer, which can complex and fix Cu 2+ , Fe 3+ , Al 3+ , and thus significantly improve the purification effect on impurity ions, thereby greatly improving the purity of the product iridium oxide. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0031] Preparation of the purification agent

[0032] The method is as follows:

[0033] S1. Preparation of the shrunken mesoporous silica nanospheres: 0.3 g of citric acid and 1 g of cetyltrimethylammonium chloride were mixed into 100 mL of water, 5 g of tetraethyl orthosilicate was added, the pH value of the solution was adjusted to 5, stirring reaction was performed for 10 min, standing and aging was performed for 20 h, 95℃ heating crystallization was performed for 20 h, centrifugation, washing, drying, and calcination at 500℃ for 2 h were performed to obtain the shrunken mesoporous silica nanospheres;

[0034] S2. Modification: 1 g of the shrunken mesoporous silica nanospheres was added into 100 mL of ethanol, 0.2 g of the composite silane coupling agent was added, heating was performed to 40℃, stirring reaction was performed for 2 h, centrifugation, washing, and drying were performed to obtain the modified nanospheres;

[0035] The composite silane coupling agent comprises silane coupling agent KH602 and silane coupling agent KH580, and the mass ratio is 5:2;

[0036] S3. Preparation of the nanocage: 1 g of the modified nanospheres was added into 50 mL of dichloromethane, 0.05 g of tris(4-benzaldehyde)amine was added, stirring reaction was performed at room temperature for 1 h to obtain the nanocage modified nanospheres;

[0037] S4. Preparation of the purification agent: 0.2 g of glutamic acid and 0.1 g of aspartic acid were added into 150 mL of water, 0.2 g of N-hydroxysuccinimide and 0.2 g of 1-ethyl-(3-dimethylaminopropyl)carbonyldiimidazole were added, stirring activation was performed for 30 min, 1 g of the nanocage modified nanospheres was added, stirring reaction was performed for 10 h, centrifugation, washing, and drying were performed to obtain the purification agent.

[0038] Preparation Example 2 Preparation of Purifying Agent

[0039] Here’s how:

[0040] S1. Preparation of shrinking mesoporous silica nanospheres: 0.5 g of citric acid and 1.2 g of hexadecyltrimethylammonium bromide were mixed in 100 mL of water, and 7 g of tetraethyl orthosilicate was added. The solution was adjusted to pH 6 with stirring for 20 min, allowed to stand for 24 h, and crystallized by heating at 100°C for 24 h. The resulting product was centrifuged, washed, dried, and calcined at 500°C for 2 h to obtain shrinking mesoporous silica nanospheres.

[0041] S2. Modification: 1 g of shrunken mesoporous silica nanospheres was added to 100 mL of ethanol, 0.3 g of a composite silane coupling agent was added, and the mixture was heated to 50°C and stirred for 4 h. The mixture was centrifuged, washed, and dried to obtain modified nanospheres.

[0042] The composite silane coupling agent includes silane coupling agent KH792 and silane coupling agent KH590, with a mass ratio of 7:3;

[0043] S3. Preparation of nanocages: 1 g of modified nanospheres was added to 50 mL of dichloromethane, 0.1 g of tris(4-benzaldehyde)amine was added, and the reaction was stirred at room temperature for 3 h to obtain nanocage-modified nanospheres;

[0044] S4. Preparation of a purifying agent: 0.3 g of glutamic acid and 0.2 g of aspartic acid were added to 150 mL of water, 0.3 g of N-hydroxysuccinimide and 0.3 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added, and the mixture was stirred and activated for 30 min. 1 g of nanocage-modified nanospheres was added, and the mixture was stirred and reacted for 15 h. The mixture was centrifuged, washed, and dried to obtain a purifying agent.

[0045] Preparation Example 3 Preparation of Purifying Agent

[0046] Here’s how:

[0047] S1. Preparation of shrinking mesoporous silica nanospheres: 0.4 g of citric acid and 1.1 g of hexadecyltrimethylammonium bromide were mixed in 100 mL of water, and 6 g of ethyl orthosilicate was added. The solution was adjusted to pH 5.5 with stirring for 15 min, allowed to stand for 22 h, and crystallized by heating at 100°C for 22 h. The resulting product was centrifuged, washed, dried, and calcined at 500°C for 2 h to obtain shrinking mesoporous silica nanospheres.

[0048] S2. Modification: 1 g of shrunken mesoporous silica nanospheres was added to 100 mL of ethanol, 0.25 g of a composite silane coupling agent was added, and the mixture was heated to 45°C and stirred for 3 h. The mixture was centrifuged, washed, and dried to obtain modified nanospheres.

[0049] The composite silane coupling agent includes silane coupling agent KH792 and silane coupling agent KH590, with a mass ratio of 6:2.5;

[0050] S3. Preparation of nanocages: 1 g of modified nanospheres was added to 50 mL of dichloromethane, 0.07 g of tris(4-benzaldehyde)amine was added, and the reaction was stirred at room temperature for 2 h to obtain nanocage-modified nanospheres;

[0051] S4. Preparation of a purifying agent: 0.25 g of glutamic acid and 0.15 g of aspartic acid were added to 150 mL of water, 0.25 g of N-hydroxysuccinimide and 0.25 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added, and the mixture was stirred and activated for 30 min. 1 g of nanocage-modified nanospheres was added, and the reaction was stirred for 12 h. The mixture was centrifuged, washed, and dried to obtain a purifying agent.

[0052] Comparative Preparation Example 1

[0053] Compared with Preparation Example 3, the difference is that citric acid is not added in step S1.

[0054] The details are as follows:

[0055] S1. Preparation of mesoporous silica nanospheres: 1.5 g of hexadecyltrimethylammonium bromide was mixed with 100 mL of water, and 6 g of ethyl orthosilicate was added. The pH of the solution was adjusted to 5.5, and the reaction was stirred for 15 min. The solution was allowed to stand for 22 h, and then heated at 100°C for crystallization for 22 h. The solution was centrifuged, washed, dried, and calcined at 500°C for 2 h to obtain mesoporous silica nanospheres.

[0056] Comparative Preparation Example 2

[0057] Compared with Preparation Example 3, the difference is that the composite silane coupling agent is a single silane coupling agent KH792.

[0058] Comparative Preparation Example 3

[0059] Compared with Preparation Example 3, the difference is that the composite silane coupling agent is a single silane coupling agent KH590.

[0060] Comparative Preparation Example 4

[0061] Compared with Preparation Example 3, the difference is that step S3 is not performed.

[0062] The details are as follows:

[0063] S1. Preparation of the shrunken mesoporous silica nanospheres: 0.4 g of citric acid and 1.1 g of cetyltrimethylammonium bromide were mixed into 100 mL of water, 6 g of tetraethyl orthosilicate was added, the pH value of the solution was adjusted to 5.5, the reaction was stirred for 15 min, it was left to stand for aging for 22 h, it was heated for crystallization at 100℃ for 22 h, it was centrifuged, washed, dried, and calcined at 500℃ for 2 h to obtain the shrunken mesoporous silica nanospheres;

[0064] S2. Modification: 1 g of the shrunken mesoporous silica nanospheres was added into 100 mL of ethanol, 0.25 g of the composite silane coupling agent was added, it was heated to 45℃, the reaction was stirred for 3 h, it was centrifuged, washed, and dried to obtain the modified nanospheres;

[0065] The composite silane coupling agent comprises silane coupling agent KH792 and silane coupling agent KH590, and the mass ratio is 6:2.5;

[0066] S3. Preparation of the purification agent: 0.25 g of glutamic acid and 0.15 g of aspartic acid were added into 150 mL of water, 0.25 g of N-hydroxysuccinimide and 0.25 g of 1-ethyl-(3-dimethylaminopropyl) carbonyldiimidazole were added, it was stirred for activation for 30 min, 1 g of the modified nanospheres was added, the reaction was stirred for 12 h, it was centrifuged, washed, and dried to obtain the purification agent.

[0067] Comparative Preparation Example 5

[0068] Compared with Preparation Example 3, the difference is that step S4 is not performed.

[0069] The details are as follows:

[0070] S1. Preparation of the shrunken mesoporous silica nanospheres: 0.4 g of citric acid and 1.1 g of cetyltrimethylammonium bromide were mixed into 100 mL of water, 6 g of tetraethyl orthosilicate was added, the pH value of the solution was adjusted to 5.5, the reaction was stirred for 15 min, it was left to stand for aging for 22 h, it was heated for crystallization at 100℃ for 22 h, it was centrifuged, washed, dried, and calcined at 500℃ for 2 h to obtain the shrunken mesoporous silica nanospheres;

[0071] S2. Modification: 1 g of the shrunken mesoporous silica nanospheres was added into 100 mL of ethanol, 0.25 g of the composite silane coupling agent was added, it was heated to 45℃, the reaction was stirred for 3 h, it was centrifuged, washed, and dried to obtain the modified nanospheres;

[0072] The composite silane coupling agent comprises silane coupling agent KH792 and silane coupling agent KH590, and the mass ratio is 6:2.5;

[0073] S3. Preparation of nanocage: 1 g of modified nanospheres was added to 50 mL of dichloromethane, 0.07 g of tris(4-benzaldehyde)amine was added, and the reaction was stirred at room temperature for 2 h to obtain nanocage modified nanospheres, which were the purification agent.

[0074] Example 1

[0075] The method of the present embodiment for efficiently recovering metallic iridium from waste iridium waste material comprises the following steps:

[0076] (1) The titanium substrate was stripped using a high-pressure water jet with a pressure of 180 MPa;

[0077] (2) The stripped titanium substrate was added to a mixed acid, which was a mixture of hydrochloric acid and nitric acid, the concentration of the hydrochloric acid was 5 wt%, the concentration of the nitric acid was 12 wt%, and the titanium substrate was dissolved at a gradient temperature, 60°C for 30 min, 85°C for 40 min, filtered, and the filtrate was reserved;

[0078] (3) The phosphorus tributylate / kerosene system was added to the filtrate, the content of the phosphorus tributylate was 20 wt%, the phosphorus tributylate / kerosene system was separated, 5 wt% of dilute hydrochloric acid was added for back extraction, and the iridium extraction liquid was obtained after separation;

[0079] (4) The purification agent prepared in Preparation Example 1 was added to the iridium extraction liquid, 500 W ultrasonic purification was performed for 20 min, the purification agent was separated, the addition amount of the purification agent was 2 wt%, the purification agent was sequentially washed with EDTA solution and deionized water, dried, and reused, solid ammonium chloride was added to the filtrate for precipitation, filtered, the solid was washed with an ammonium chloride solution, dried, calcined at 200°C for 3 h, and the iridium oxide product was obtained, the tail gas was absorbed and purified by passing into a 10 wt% NaOH solution, and the emission standard GB16297 was reached.

[0080] Example 2

[0081] The method of the present embodiment for efficiently recovering metallic iridium from waste iridium waste material comprises the following steps:

[0082] (1) The titanium substrate was stripped using ultrasonic vibration with a power of 2500 W for 30 min;

[0083] (2) The stripped titanium substrate was added to a mixed acid, which was a mixture of hydrochloric acid and nitric acid, the concentration of the hydrochloric acid was 10 wt%, the concentration of the nitric acid was 8 wt%, and the titanium substrate was dissolved at a gradient temperature, 70°C for 10 min, 95°C for 20 min, filtered, and the filtrate was reserved;

[0084] (3) The phosphorus tributylate / kerosene system was added to the filtrate, the content of the phosphorus tributylate was 40 wt%, the phosphorus tributylate / kerosene system was separated, 10 wt% of dilute hydrochloric acid was added for back extraction, and the iridium extraction liquid was obtained after separation;

[0085] (4) The purified agent prepared in Preparation Example 2 is added to the iridium extraction liquid, and ultrasonic purification is performed at 1000 W for 40 min. The purified agent is separated, and the addition amount of the purified agent is 3 wt%. The purified agent is sequentially washed with an EDTA solution and deionized water, dried, and reused. Solid ammonium chloride is added to the filtrate for precipitation, filtered, and the solid is washed with an ammonium chloride solution, dried, and calcined at 240°C for 3 h to obtain an iridium oxide product. Tail gas is absorbed and purified by passing into a 20 wt% KOH solution, and the emission standard of GB16297 is reached.

[0086] Example 3

[0087] The method of the present embodiment for efficiently recovering metallic iridium from waste iridium waste material includes the following steps:

[0088] (1) The titanium substrate is stripped using a high-pressure water jet with a pressure of 200 MPa;

[0089] (2) The stripped titanium substrate is added to a mixed acid, which is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 7 wt% and a nitric acid concentration of 10 wt%. Gradient temperature dissolution is performed at 65°C for 20 min and at 90°C for 30 min. Filtration is performed, and the filtrate is retained;

[0090] (3) Tributyl phosphate / kerosene system is added to the filtrate, and the content of tributyl phosphate is 30 wt%. Extraction is performed, the tributyl phosphate / kerosene system is separated, 7 wt% dilute hydrochloric acid is added for back extraction, and separation is performed to obtain an iridium extraction liquid;

[0091] (4) The purified agent prepared in Preparation Example 3 is added to the iridium extraction liquid, and ultrasonic purification is performed at 700 W for 30 min. The purified agent is separated, and the addition amount of the purified agent is 2.5 wt%. The purified agent is sequentially washed with an EDTA solution and deionized water, dried, and reused. Solid ammonium chloride is added to the filtrate for precipitation, filtered, and the solid is washed with an ammonium chloride solution, dried, and calcined at 220°C for 2 h to obtain an iridium oxide product. Tail gas is absorbed and purified by passing into a 15 wt% NaOH solution, and the emission standard of GB16297 is reached.

[0092] Comparative Example 1

[0093] Compared with Example 3, the difference is that the purified agent is prepared in Comparative Preparation Example 1.

[0094] Comparative Example 2

[0095] Compared with Example 3, the difference is that the purified agent is prepared in Comparative Preparation Example 2.

[0096] Comparative Example 3

[0097] Compared with Example 3, the difference is that the purified agent is prepared in Comparative Preparation Example 3.

[0098] Comparative Example 4

[0099] The difference compared with Example 3 is that the purification agent is prepared by Comparative Preparation Example 4.

[0100] Comparative Example 5

[0101] The difference compared with Example 3 is that the purification agent is prepared by Comparative Preparation Example 5.

[0102] Comparative Example 6

[0103] The difference compared with Example 3 is that the ion exchange chromatography (Dowex resin) is used to purify the iridium extract in step (4) at a flow rate of 2 BV / h.

[0104] Test Example 1

[0105] The iridium oxide products prepared by Examples 1-3 and Comparative Examples 1-5 are tested for purity by ICP-MS, the specific surface area is determined by 3-FLEX3500 multi-station high-throughput gas adsorption instrument, and the iridium recovery rate is tested, and the results are shown in Table 1.

[0106] Table 1

[0107] Group Purity of iridium oxide product (%) Specific surface area (m 2 / g) Iridium recovery rate (%) Example 1 99.99 55.2 97.7 Example 2 99.98 53.9 97.5 Example 3 99.99 57.3 97.9 Comparative Example 1 99.10 48.1 95.7 Comparative Example 2 99.45 51.5 96.8 Comparative Example 3 97.22 38.3 92.2 Comparative Example 4 98.57 42.1 94.1 Comparative Example 5 98.92 46.2 95.0 Comparative Example 6 99.95 48.7 97.0

[0108] From the above table, it can be seen that the iridium oxide products prepared by the methods in Examples 1-3 have high purity, high recovery rate, and large specific surface area.

[0109] The above description is only the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for efficiently recovering metallic iridium from waste iridium waste, characterized in that: The following steps are involved: (1) Using high-pressure water jet or ultrasonic vibration to peel off the titanium matrix; (2) adding the titanium matrix obtained by stripping into a mixed acid, dissolving it by increasing the temperature gradually, filtering it, and retaining the filtrate; (3) adding tributyl phosphate / kerosene system to the filtrate, extracting, separating the tributyl phosphate / kerosene system, adding dilute hydrochloric acid for back extraction, separating, and obtaining an iridium extract; (4) adding a purifying agent to the iridium extract, ultrasonically purifying, separating the purifying agent, washing the purifying agent with EDTA solution and deionized water in sequence, drying, and reusing; adding solid ammonium chloride to the filtrate for precipitation, filtering, washing the solid with ammonium chloride solution, drying, and calcining to obtain an iridium oxide product; passing the tail gas into an alkaline solution for absorption and purification, and meeting the GB16297 emission standard.

2. The method for efficiently recovering metallic iridium from waste iridium waste according to claim 1, wherein: The pressure of the high-pressure water jet is 180-220 MPa, the power of the ultrasonic vibration is 1500-2500 W, and the time is 10-30 minutes.

3. The method for efficiently recovering metallic iridium from waste iridium waste according to claim 1, wherein: The mixed acid is a mixture of hydrochloric acid and nitric acid, the hydrochloric acid concentration is 5-10wt%, and the nitric acid concentration is 8-12wt%. The gradient heating conditions are 60-70°C, maintained for 10-30 minutes, and 85-95°C, maintained for 20-40 minutes.

4. The method for efficiently recovering metallic iridium from waste iridium waste material according to claim 1, wherein: The content of tributyl phosphate in the tributyl phosphate / kerosene system is 20-40 wt %, and the concentration of the dilute hydrochloric acid is 5-10 wt %.

5. The method for efficiently recovering metallic iridium from waste iridium waste according to claim 1, wherein: The amount of the purifying agent added to the iridium extract is 2-3wt%, the ultrasonic power is 500-1000W, the time is 20-40min, the calcination temperature is 200-240°C, the time is 1-3h, and the alkali solution is a NaOH or KOH solution with a concentration of 10-20wt%.

6. The method for efficiently recovering metallic iridium from waste iridium waste according to claim 1, wherein: The preparation method of the purifying agent is as follows: S1. Preparation of shrinking mesoporous silica nanospheres: citric acid and a porogen were mixed and added to water, and ethyl orthosilicate was added. The pH of the solution was adjusted, stirred, allowed to react, allowed to stand for aging, heated for crystallization, centrifuged, washed, dried, and calcined to produce shrinking mesoporous silica nanospheres. S2. Modification: adding the shrunken mesoporous silica nanospheres to ethanol, adding a composite silane coupling agent, heating and stirring to react, centrifuging, washing, and drying to obtain modified nanospheres; S3. Preparation of nanocages: The modified nanospheres were added to dichloromethane, tris(4-benzaldehyde)amine was added, and the reaction was stirred at room temperature to obtain nanocage-modified nanospheres; S4. Preparation of a purifying agent: Add glutamic acid and aspartic acid to water, add N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide, stir to activate, add nanocage-modified nanospheres, stir to react, centrifuge, wash, and dry to obtain a purifying agent.

7. The method for efficiently recovering metallic iridium from waste iridium waste according to claim 6, wherein: In step S1, the mass ratio of citric acid, porogen and tetraethyl orthosilicate is 0.3-0.5:1-1.2:5-7, the porogen is hexadecyltrimethylammonium chloride or hexadecyltrimethylammonium bromide, the pH value of the solution is adjusted to 5-6, the stirring reaction time is 10-20 minutes, the static aging time is 20-24 hours, and the heating crystallization temperature is 95-100°C for 20-24 hours.

8. The method for efficiently recovering metallic iridium from waste iridium waste according to claim 6, wherein: The mass ratio of the shrinking mesoporous silica nanospheres and the composite silane coupling agent in step S2 is 10:2-3, the composite silane coupling agent includes a bisaminosilane coupling agent and a silane coupling agent with a mercapto group, the mass ratio is 5-7:2-3, the bisaminosilane coupling agent is KH602 or KH792, the silane coupling agent with a mercapto group is KH580 or KH590, the temperature of the heating and stirring reaction is 40-50 ° C, and the time is 2-4h.

9. The method for efficiently recovering metallic iridium from waste iridium waste according to claim 6, wherein: In step S3, the mass ratio of the modified nanospheres to tris(4-benzaldehyde)amine is 10:0.5-1, and the reaction time under stirring at room temperature is 1-3 hours.

10. The method for efficiently recovering metallic iridium from waste iridium waste according to claim 6, wherein: In step S4, the mass ratio of glutamic acid, aspartic acid, N-hydroxysuccinimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and nanocage-modified nanospheres is 2-3:1-2:2-3:2-3:10, and the stirring reaction time is 10-15 hours.