Recovery method for metal iridium in fluorine-containing strong-acid iridium-containing waste liquid and recovery adsorption material
By fluorinating porous carbon materials and modifying them with aminopyridine, combined with specific process optimization, the problem of low iridium recovery efficiency of traditional materials in strongly acidic environments has been solved, achieving a highly efficient and selective iridium recovery effect.
Patent Information
- Application Number
- CN202511974480.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-02-27
AI Technical Summary
In existing technologies, traditional adsorption materials are easily corroded in the presence of strong acids and HF, have poor selectivity, and are difficult to achieve efficient recovery of iridium, with an adsorption rate of less than 80%.
By using porous carbon materials for fluorination and introducing -NH2 functional groups, a fluorine passivation layer and aminopyridine modification are formed in strongly acidic iridium-containing waste liquid. Combined with ascorbic acid reduction and thiourea desorption, the adsorption-desorption process is optimized to improve the adsorption rate and selectivity of iridium.
In the presence of strong acid and high concentration of competing ions, the adsorption rate of iridium reaches 93.6%, the recovery rate reaches 98.2%, and the purity of the recovered product IrO2 reaches 99.5%. The material has high selectivity and good regeneration performance.
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Figure CN121575237A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of precious metal resource recovery, in particular to a method for recovering metallic iridium from fluorine-containing strong-acid iridium-containing waste liquid and a recovery adsorption material. BACKGROUND
[0002] Iridium (Ir) is a rare precious metal and has important applications in catalysts, titanium anode materials, electronic materials and high-temperature alloys. It often exists in the form of low concentration in industrial waste liquid and coexists with high-concentration ions such as Pb 2+ , Ti 4+ in a strong-acid environment (such as HCl-HF mixed acid). In the prior art, the recovery of metallic iridium mainly adopts the adsorption method, and the traditional adsorption material is easy to be corroded and has poor selectivity. Moreover, the traditional activated carbon, ion exchange resin and other materials have insufficient stability in the presence of strong acid and HF, and are seriously interfered by competitive ions, so that the adsorption rate is low (usually less than 80%), and it is difficult to realize efficient recovery of iridium.
[0003] Therefore, it is necessary to provide a new process to solve the above technical problems. SUMMARY
[0004] The technical problem to be solved by the present application is to provide a method for recovering metallic iridium from fluorine-containing strong-acid iridium-containing waste liquid and a recovery adsorption material, which can improve the adsorption rate of metallic iridium and realize efficient recovery of iridium under the conditions of strong acid, high-concentration competitive ions and low-concentration iridium.
[0005] The first aspect of the present application is to provide a method for recovering metallic iridium from fluorine-containing strong-acid iridium-containing waste liquid, and the technical solution is as follows: A method for recovering metallic iridium from fluorine-containing strong-acid iridium-containing waste liquid, the iridium-containing waste liquid contains hydrochloric acid and hydrofluoric acid and contains high-concentration Pb 2+ , Ti 4+ , and the method for recovering metallic iridium comprises the following steps: Step S1, carbon material modification: the porous carbon material is subjected to fluorination treatment to form a fluorine passivation layer on the surface, and then 2-aminopyridine is used to modify the carbon material after fluorination treatment to introduce -NH2 on the surface; Step S2, pretreatment of the iridium-containing waste liquid: adjust the pH of the waste liquid to 0.5-1.0, and add a certain amount of Al 3+ to complex Ti 4+ in the waste liquid; Step S3, adsorption: the modified carbon material in step S1 is added to the pretreated waste liquid to form an adsorption system, and an appropriate amount of ascorbic acid is added to the adsorption system to reduce Ir 4+ to Ir 3+; the adsorption conditions are: carbon material dosage 8-10 g / L, temperature 60-70 °C, oscillation adsorption 18-24 h; after adsorption is completed, the carbon material is centrifuged; specifically, the carbon material dosage can be 8 g / L, 9 g / L or 10 g / L, or other values within the range; the adsorption temperature can be 60 °C, 65 °C or 70 °C, or other values within the range; the adsorption time can be 18 h, or 24 h, or other values within the range; Step S4, desorption and recovery of iridium: using a mixed solution of thiourea and hydrochloric acid as an eluent, thiourea and Ir 3+ to form a stable complex [Ir(S=C(NH2)2)6] 3+ , and then the Ir 3+ is desorbed from the surface of the carbon material, and the eluent is collected and rotary evaporated to obtain an enriched Ir solution; Step S5, iridium precipitation: adding NH4F and NH4Cl to the enriched Ir solution to adjust the pH to 8-9 to generate an Ir(OH)3 precipitate; Step S6, after filtering the precipitate, calcining to obtain IrO2, or reducing with hydrogen to obtain metallic Ir.
[0006] Further, in step S1, the specific surface area of the modified carbon material is >1800 m 2 / g, the pore size is 2-50 nm, and the HF corrosion resistance is characterized by a mass loss of <2% in 10 mol / L HF.
[0007] Further, in step S1, the porous carbon material is subjected to fluorination treatment, including the following steps: immersing the porous carbon material in a hydrofluoric acid solution with a mass concentration of 5-10% under stirring at 50-65 °C for 2-4 h; specifically, the concentration of the hydrofluoric acid solution can be 5% or 10%, or other values within the range; repeatedly washing the carbon material with pure water until the pH of the filtrate is 6-7; activating the carbon material with a 4-6 mol / L sodium hydroxide or potassium hydroxide solution; eluting, centrifuging and filtering, and repeatedly washing until the pH of the filtrate is 6-8, [Na / K] + <10 ppm, and finally washing with anhydrous ethanol and drying.
[0008] Further, the solid-liquid ratio of the porous carbon material to the hydrofluoric acid solution is 1:5-8, such as 1:5, 1:6, 1:7 or 1:8, or other values within the range.
[0009] Further, in step S1, the carbon material after fluorination treatment is modified, including the following steps: The fluorinated carbon material is immersed in a hydrochloric acid solution containing 2-aminopyridine, and stirred at room temperature for 6-10 hours, wherein the mass concentration of 2-aminopyridine is 0.5-2%, the concentration of hydrochloric acid is 0.1-0.2 mol / L, and the solid-liquid ratio of the carbon material to the hydrochloric acid solution is 1:8.5-1:13; specifically, the mass concentration of 2-aminopyridine can be 0.5%, 1% or 2%, or other values within the range; the concentration of hydrochloric acid can be 0.1 mol / L, 0.15 mol / L or 0.2 mol / L, or other values within the range; and the solid-liquid ratio of the carbon material to the hydrochloric acid solution can be 1:8.5, 1:10 or 1:13, or other values within the range. repeatedly washed with anhydrous ethanol; vacuum drying under reduced pressure for 10-12 hours.
[0010] Further, in step S2, the concentration of Al 3+ is 0.05-0.2 mol / L; specifically, the concentration of Al 3+ may be 0.05 mol / L, 0.1 mol / L or 0.2 mol / L, or other values within the range.
[0011] Further, in step S3, the concentration of ascorbic acid is 0.01-0.1 mol / L; specifically, the concentration of ascorbic acid can be 0.01 mol / L, 0.05 mol / L or 0.1 mol / L, or other values within the range.
[0012] Further, in step S4, the concentration of thiourea in the eluent is 1-3 mol / L, the concentration of hydrochloric acid is 0.5-2 mol / L, and the solid-liquid ratio of the carbon material to the eluent is 1:20; specifically, the concentration of thiourea in the eluent can be 1 mol / L, 2 mol / L or 3 mol / L, or other values within the range; the concentration of hydrochloric acid can be 0.5 mol / L, 1 mol / L or 2 mol / L, or other values within the range.
[0013] Further, in step S6, the calcination temperature is 500-700℃; specifically, the calcination temperature can be 500℃, 600℃ or 700℃, or other values within the range.
[0014] The second aspect of the present application provides an adsorption material for recovering metallic iridium, which is prepared by the following method: A fluorine passivation layer is formed on the surface of the porous carbon material by fluorination treatment; Then, the fluorinated carbon material is modified with 2-aminopyridine to introduce -NH2 on the surface thereof.
[0015] Compared with the prior art, the method for recovering metal iridium in fluorine-containing strong acidic iridium-containing waste liquid and the recovery adsorption material have the beneficial effects that: I. The method for recovering metal iridium in fluorine-containing strong acidic iridium-containing waste liquid provided by the application has the advantages that the modified carbon material has an iridium adsorption rate of 93.6% under the conditions of strong acid and high concentration of competitive ions, has high selectivity, strong anti-interference performance and good regeneration performance, and is suitable for iridium resource recovery in the fields of metallurgy and electronic waste treatment.
[0016] II. The method for recovering metal iridium in fluorine-containing strong acidic iridium-containing waste liquid provided by the application has the advantages that the adsorption-desorption process is optimized, the iridium recovery rate is improved while the iridium adsorption rate is improved, the iridium recovery rate reaches 98.2%, and the purity of the recovery product IrO2 reaches 99.5%. BRIEF DESCRIPTION OF DRAWINGS
[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.
[0018] Figure 1 is a BET specific surface area fitting straight line graph of the fluorine-doped porous carbon prepared by the present application; Figure 2 is a SEM morphology graph of the fluorine-doped porous carbon prepared by the present application; Figure 3 is an XRD spectrum of the fluorine-doped porous carbon prepared by the present application; Figure 4 is a pseudo-second-order kinetics model of the fluorine-doped porous carbon prepared by the present application for adsorbing iridium. DETAILED EMBODIMENTS
[0019] In order to make those skilled in the art better understand the technical solutions in the embodiments of the present application, and make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation manner of the present application will be further described.
[0020] The endpoints of the ranges and any values in the ranges disclosed herein are not limited to the precise values stated. The ranges and values should be interpreted as being approximate. The endpoints of the ranges and values are provided as exemplifications of the ranges and values. Other values within the ranges and values are neither explicitly listed nor inherently excluded. Any numerical value, however, can be expressed as approximately or approximately.
[0021] Example 1: Preparation of Fluorine-Doped Adsorbent Materials An adsorbent material is obtained by modifying porous carbon material, and the specific method is as follows: (1) Fluoride the carbon material to form a fluorine passivation layer on its surface, as follows: The porous carbon material is immersed in a 10% hydrofluoric acid solution and stirred at 200-300 rpm for 2-4 hours in a water bath at 60℃. The porous carbon material is selected from coconut shell carbon or fruit shell carbon, and the hydrofluoric acid is selected from analytical grade containing 40% HF. The solid-liquid ratio of the porous carbon material to the hydrofluoric acid solution is 1:6. After the reaction is complete, wash the carbon material repeatedly with pure water until the pH of the filtrate is 6-7. Activate the carbon material with a 5 mol / L sodium hydroxide or potassium hydroxide solution to improve its adsorption capacity and catalytic activity. Elute, centrifuge, filter, and wash repeatedly until the filtrate pH is 6-8, [Na / K] + <10ppm, finally wash once with anhydrous ethanol, and dry at 105℃ for 2 hours to obtain the product for use.
[0022] (2) Modify the fluorinated carbon material by introducing -NH2 functional groups on its surface, as follows: The fluorinated carbon material was immersed in a hydrochloric acid solution containing 2-aminopyridine and stirred at room temperature for 8 hours. The mass concentration of 2-aminopyridine was 1%, the concentration of hydrochloric acid was 0.1 mol / L, the solid-liquid ratio of carbon material to hydrochloric acid solution was 1:10, and the stirring speed was 100-200 rpm. Wash repeatedly with anhydrous ethanol until no 2-aminopyridine residue remains in the filtrate; Vacuum drying for 12 hours.
[0023] The performance of the adsorbent material prepared by this invention is described in detail below. The composition of the waste liquid used in the experiment was: HCl:HF:H2O = 200:62.5:237.5 (volume ratio), containing Ir 117 mg / L and Pb. 2+ 5.63 g / L, Ti 4+ 46.5 g / L.
[0024] In this embodiment, the obtained carbon material is fluorine-doped porous carbon, and its BET specific surface area analysis data are shown in Table 1: Table 1: BET Specific Surface Area Analysis Data
[0025] Plot a line with p / p0 as the x-axis and p / [V(p0-p)] as the y-axis. The fitted line has a slope of 0.00223 and an intercept of 0.000159. Figure 1As shown. According to calculations, the specific surface area of the porous carbon in this embodiment is approximately 1822 m². 2 / g.
[0026] The SEM morphology of the fluorine-doped porous carbon in this embodiment is shown below. Figure 2 As shown. By Figure 2 It can be seen that the white powder covering the surface of the carbon material is element F, which is uniformly distributed in the activated carbon. The pore size of the modified carbon material is 2-50 nm.
[0027] The XRD pattern of the fluorine-doped porous carbon in this embodiment is as follows: Figure 3 As shown. By Figure 3 It is known that fluorine (F) is clearly present in the carbon material. Therefore, it has corrosion resistance, and tests show that the mass loss in 10 mol / L HF is <2%.
[0028] Using the Freundlich model, combined with the activated carbon pore structure (quantitatively corrected), the theoretical maximum adsorption capacity can be calculated.
[0029]
[0030] By revising the formula, the maximum adsorption capacity formula can be obtained:
[0031]
[0032] in: A 微孔 : Micropore internal surface area of activated carbon (unit: cm² / g, total internal surface area of micropores per gram of activated carbon). M Ir Molar mass of iridium (unit: g / mol, approximately 192.22 g / mol); σ Ir Cross-sectional area of a single iridium particle (atom / ion / complex) (unit: cm² / particle); N A Avogadro's constant (unit: mol) -1 ).
[0033] BET surface area analysis shows that C 微孔 =1822m 2 / g=1.822×10 21 nm 2 / g; M Ir =192.22 g / mol; σ Ir =0.4nm 2 / indivual; N A =6.022×1023 per mol.
[0034] calculate (Unit: mg / g); The scientific selection of the adsorption time of modified carbon material for iridium was achieved by obtaining time-adsorption amount data through adsorption kinetic experiments and fitting the data with pseudo-first-order and pseudo-second-order kinetic models (the most commonly used adsorption rate models). Combined with the convergence and rate of change analysis of equilibrium adsorption amount, the time when the equilibrium state has been reached or is close to the equilibrium state was calculated.
[0035] Given: Original iridium concentration in waste liquid: C0 = 117 mg / L; Iridium concentration in the filtrate after 24 hours: C e,24h =7.49 mg / L; The equilibrium adsorption capacity over 24 hours can be calculated (taking 100 mL of waste liquid + 1 g of activated carbon as an example):
[0036] Five parallel samples (1g modified activated carbon + 100mL original waste liquid) were taken at different time points (e.g., 0, 2, 4, 8, 12, 18, 24, 36, and 48 hours). After centrifugation, the iridium concentration in the supernatant was measured, and the real-time adsorption capacity at each time point was calculated. Time-adsorption capacity data were obtained through experiments (see Table 2), and a pseudo-second-order model was fitted.
[0037] Table 2: Time-Adsorption Capacity Data
[0038] The pseudo-second-order model describes the rate-driven process dominated by chemisorption (the adsorption rate is proportional to the square of the unoccupied active sites), and its integral form (after linearization) is:
[0039] Quasi-second-order dynamic model:
[0040] Simplified as the change in adsorption amount over time:
[0041] Based on Table 2 and the quasi-second-order dynamic model, the following graphs are drawn: Figure 4 As shown.
[0042] Based on the fitting results of the pseudo-second-order dynamic model: The equilibrium adsorption capacity Γe = 12.94 mg / g The pseudo-second-order rate constant k2 = 0.0150 g / (mg·h) Coefficient of determination R 2 = 0.966 It is shown that the adsorption process of modified activated carbon for iridium is in good agreement with the pseudo-second-order kinetic model, indicating that chemical adsorption is the main rate-controlling step. As can be seen from the figure, the adsorption capacity gradually increases with time and tends to be balanced around 24 hours, verifying the scientificity of 18-24 hours as the adsorption time.
[0043] Selectivity of modified carbon material for adsorbing metal ions High selectivity of modified activated carbon for Ir (relative to Pb 2+ , Ti 4+ ), and the selectivity coefficient is calculated, which needs to be analyzed by combining the simulation of waste liquid adsorption experiments with the ratio of distribution coefficient (Kd) or kinetic constant (k2).
[0044] Take modified carbon material (1 g) and add 100 mL of original waste liquid (Erlenmeyer flask), seal and place in a constant temperature oscillator (25°C, 150 rpm) for 24 h to balance. Sample analysis: centrifugal separation of activated carbon, take supernatant and use ICP-OES (measure Ir, Pb, Ti) to detect equilibrium concentration Ce, Ir , Ce, Pb , Ce, Ti . The experimental data are shown in Table 3.
[0045] Table 3: Adsorption data of modified carbon material for different metal ions
[0046] Calculate the distribution coefficient K d : According to , we have: K d,Ir = 10.95 / 98.56 ≈ 0.1111 L / g; K d,Pb = 11.4 / 5513 ≈ 0.0021 L / g; K d,Ti = 48.8 / 46012 ≈ 0.0011 L / g.
[0047] Calculate the selectivity coefficient: Selectivity for Pb 2+ : K Ir / Pb = 0.1111 / 0.0021 ≈ 52.9 (greater than 30-50); Selectivity for Ti 4+ : K Ir / Ti = 0.1111 / 0.0011 ≈ 101 (very high selectivity).
[0048] The equilibrium concentration and adsorption capacity are obtained by simulating the waste liquid adsorption experiment, and the distribution coefficient ratio can directly prove the high selectivity of the modified activated carbon to Ir (30-50 times of Pb 2+ ). The experimental data need to be strictly controlled in terms of waste liquid composition and adsorption conditions to ensure that the results truly reflect the performance in the actual scene.
[0049] From the above analysis, it can be seen that the selectivity of the modified carbon material prepared by the application to Ir is significantly higher than that of Pb 2+ , Ti 4+ , and can be applied to the extraction of iridium from waste liquid with high acidity and multiple interfering ions.
[0050] Based on the modified carbon material of Example 1, the application provides a method for recovering metallic iridium in a fluorine-containing strong acid iridium-containing waste liquid, as shown in Example 2.
[0051] Example 2: Method for recovering metallic iridium in a fluorine-containing strong acid iridium-containing waste liquid The composition of the waste liquid is HCl:HF:H2O = 200:62.5:237.5 (volume ratio), containing Ir 117 mg / L, Pb 2+ 5.63g / L, Ti 4+ 46.5 g / L.
[0052] In this embodiment, the method for recovering metallic iridium includes the following steps: Step S1, modification of carbon material, the method being as shown in Example 1; Step S2, pretreatment of the iridium-containing waste liquid: adjusting the pH of the waste liquid to 0.5-1.0, and adding a certain amount of Al 3+ complexing Ti 4+ in the waste liquid, wherein the concentration of Al 3+ is 0.1 mol / L; By adding a small amount of Al 3+ as a competitive agent, Al 3+ and F - form a more stable [AlF6] 3- , replacing part of [TiF6] 2- , and realizing the complexation of Ti 4+ in the waste liquid. In this embodiment, the amount of Al 3+ added is 1-10 ml, and the Al 3+ is calculated based on 0.1 mol / L aluminum chloride solution.
[0053] Step S3, adsorption: adding the modified carbon material of step S1 into the pretreated waste liquid to form an adsorption system, and adding 0.05 mol / L ascorbic acid in the adsorption system to reduce Ir 4+ to Ir 3+; adsorption conditions: carbon material dosage 8-10 g / L, temperature 60-70℃, stirring and oscillation adsorption at 200-300 rpm for 18-24 h; after adsorption, centrifugal separation of carbon material; Step S4, desorption and recovery of iridium: using a mixed solution of thiourea and hydrochloric acid as eluent, stirring at room temperature for 1 h, thiourea and Ir 3+ to form stable complex [Ir(S=C(NH2)2)6] 3+ , and then the Ir 3+ is desorbed from the surface of the carbon material, and the eluent is collected and rotary evaporated to obtain an enriched Ir solution; wherein the concentration of thiourea in the eluent is 2 mol / L, the concentration of hydrochloric acid is 1 mol / L, and the solid-liquid ratio of carbon material to eluent is 1:20 (mass ratio); Step S5, iridium precipitation: adding NH4F and NH4Cl to the enriched Ir solution to adjust the pH to 8-9 to generate Ir(OH)3 precipitate; Step S6, calcination of the precipitate after filtration to obtain IrO2, with a calcination temperature of 550℃; or hydrogen reduction to obtain metallic Ir.
[0054] The metal iridium recovery method of Example 2 was used to conduct multiple identical tests, and the experimental results are shown in Table 4.
[0055] Table 4: Results of multiple tests using the same recovery method
[0056] As can be seen from Table 4, the iridium concentration of the waste liquid after adsorption is reduced to about 7.43 mg / L, with an adsorption rate of 93.65%. After TU-HCl desorption of the carbon material, the iridium recovery rate is 98.2%, and the purity of the final product IrO2 is 99.5%.
[0057] Under the same conditions, the unmodified activated carbon has an adsorption rate of only 41.3%, and the corrosion weight loss of the carbon material is >50%.
[0058] Comparative Example 1 The composition of the waste liquid is the same as that of Example 2.
[0059] The adsorption material of this example is a porous activated carbon that is fluorinated but not amino-modified. The method of fluorination modification is the same as that of Example 1.
[0060] Comparative Example 2 The composition of the waste liquid is the same as that of Example 2.
[0061] The adsorption material of this example is a porous activated carbon that is amino-modified but not fluorinated. The method of amino modification is the same as that of Example 1.
[0062] Comparative tests were conducted on the adsorbent materials of Example 1, Comparative Example 1 and Comparative Example 2, and the test method was as follows: 1 g of the modified carbon material of Example 1, the carbon material of Comparative Example 1 and the carbon material of Comparative Example 2 were respectively added into 100 mL of the original waste liquid (an Erlenmeyer flask), and then sealed and placed in a constant temperature oscillator (25℃, 150 rpm) for oscillation for 24 h until equilibrium.
[0063] Sampling analysis: centrifugal separation of activated carbon, filtration, and determination of the content of Ir in the filtrate by ICP-OES. The results are shown in Table 5.
[0064] Table 5: Effect of different adsorbent materials on adsorption rate
[0065] From the above data analysis, it can be seen that the modified titanium material of Example 1 has the best adsorption rate for iridium; the adsorption rate of the carbon material of Comparative Example 1 for iridium is higher than that of ordinary activated carbon, but is much lower than that of the final modified material, because it lacks selective functional groups; and the carbon material of Comparative Example 2 is corroded in a strong HF environment, even if it has good functional groups, the material carrier itself will be corroded, resulting in a sharp decline or failure in performance.
[0066] Therefore, the porous carbon material is modified by fluorination treatment and amino pyridine modification in the present application, which improves the adsorption rate of low-concentration iridium in a high-acidity and high-concentration competitive ion environment, and has high selectivity, strong anti-interference and good regeneration performance, and is suitable for iridium resource recovery in the fields of metallurgy and electronic waste treatment. Through optimization of the adsorption-desorption process, the adsorption rate of iridium can reach 93.6%, the recovery rate of iridium can reach 98.2%, and the purity of the recovered product IrO2 can reach 99.5%.
[0067] The embodiments of the present application are described in detail above, but the present application is not limited to the described embodiments. Various changes, modifications, replacements and variations of these embodiments made by those skilled in the art without departing from the principles and spirits of the present application still fall within the protection scope of the present application.
Claims
1. A method for recovering metallic iridium from a fluorine-containing strong acidic iridium-containing waste solution, characterized by, The waste solution containing iridium contains hydrochloric acid and hydrofluoric acid, and contains high concentration of Pb 2+ , Ti 4+ The recovery method of metallic iridium includes the following steps: Step S1, carbon material modification: porous carbon material is fluorinated to form a fluorine passivation layer on its surface, and then 2-aminopyridine is used to modify the fluorinated carbon material to introduce -NH2 on its surface; Step S2, pretreatment of the iridium-containing waste solution: adjust the pH of the waste solution to 0.5-1.0, and add a certain amount of Al 3+ complexing Ti in the waste solution 4+ ; Step S3, adsorption: add the modified carbon material of step S1 into the pretreated waste liquid to form an adsorption system, and add an appropriate amount of ascorbic acid to the adsorption system to reduce Ir 4+ to Ir 3+ ; the adsorption conditions are: carbon material dosage 8-10 g / L, temperature 60-70 ℃, and oscillation adsorption time 18-24 h; After adsorption, the carbon material is centrifuged and separated; Step S4, desorption and recovery of iridium: using a mixed solution of thiourea and hydrochloric acid as eluent, thiourea and Ir 3+ to form stable complex [Ir(S=C(NH2)2)6] 3+ , and Ir 3+ is desorbed from the surface of the carbon material, the eluent is collected and rotary evaporated to obtain an enriched Ir solution; Step S5, iridium precipitation: NH4F and NH4Cl are added to the enriched Ir solution to adjust the pH to 8-9 to generate Ir(OH)3 precipitate; Step S6, after filtering the precipitate, calcination is performed to obtain IrO2, or hydrogen reduction is performed to obtain metallic Ir.
2. The method for recovering metallic iridium from a fluorine-containing strong acidic iridium-containing waste solution according to claim 1, characterized by, In step S1, the modified carbon material has a specific surface area > 1800 m 2 / g, a pore size of 2-50 nm, and a HF corrosion resistance characterized by a mass loss < 2% in 10 mol / L HF.
3. The method for recovering metallic iridium from a fluorine-containing strong acidic iridium-containing waste solution according to claim 2, characterized by, In step S1, the porous carbon material is fluorinated, including the following steps: The porous carbon material is immersed in a hydrofluoric acid solution with a mass concentration of 5-10%, and is soaked at 50-65°C under stirring for 2-4h; The carbon material is repeatedly washed with pure water until the pH of the filtrate is 6-7; The carbon material is activated with a 4-6 mol / L sodium hydroxide or potassium hydroxide solution; Eluted, centrifugal filtered, and washed repeatedly until filtrate pH = 6-8, [Na / K] + <10 ppm, and finally washed with absolute ethanol and dried.
4. The method for recovering metallic iridium from a fluorine-containing strong acidic iridium-containing waste solution according to claim 3, characterized by, The solid-liquid ratio of the porous carbon material to the hydrofluoric acid solution is 1:5-8.
5. The method according to claim 1, wherein the method is characterized by, In step S1, the fluorinated carbon material is modified, including the following steps: The fluorinated carbon material is immersed in a hydrochloric acid solution containing 2-aminopyridine and stirred at room temperature for 6-10h, wherein the mass concentration of 2-aminopyridine is 0.5-2%, the concentration of hydrochloric acid is 0.1-0.2 mol / L, and the solid-liquid ratio of the carbon material to the hydrochloric acid solution is 1:8.5-1:13; Repeatedly washed with anhydrous ethanol; Vacuum reduced pressure drying for 10-12h.
6. The method for recovering metallic iridium from a fluorine-containing strong acidic iridium-containing waste solution according to claim 1, characterized by, In step S2, the concentration of Al 3+ is 0.05-0.2 mol / L.
7. The method according to claim 1, wherein the method is characterized by, In step S3, the concentration of ascorbic acid is 0.01-0.1 mol / L.
8. The method for recovering metallic iridium from a fluorine-containing strong acidic iridium-containing waste solution according to claim 1, characterized by, In step S4, the concentration of thiourea in the eluent is 1-3 mol / L, the concentration of hydrochloric acid is 0.5-2 mol / L, and the solid-liquid ratio of the carbon material to the eluent is 1:
20.
9. The method according to claim 1, wherein the method is characterized by, In step S6, the calcination temperature is 500-700°C.
10. An adsorbent material for the recovery of metallic iridium, characterized in that, The following method is used to prepare: The porous carbon material is fluorinated to form a fluorine passivation layer on its surface; Then 2-aminopyridine is used to modify the fluorinated carbon material to introduce -NH2 on its surface.