Method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid

Abstract

The invention discloses a method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid in the field of chemical waste liquid recovery, which comprises the following steps: taking the rhodium-containing waste liquid, filtering and removing impurities, then adjusting the pH value, adding cocoanut active charcoal, stirring and adsorbing, and then filtering and separating; taking a 4-MPy / MOF (at) silica gel adsorbent as a selective adsorbent, carrying out dynamic adsorption on the rhodium-containing waste liquid, removing iron after adsorption, and carrying out cyclic desorption; introducing chlorine into rhodium-enriched liquid, stirring for reaction, carrying out secondary adsorption by using zinc-loaded activated carbon, and then carrying out adsorption purification by using ion exchange resin; and finally, placing the rhodium liquid in a container, adding a seed crystal, and carrying out reduced pressure crystallization to obtain rhodium trichloride hydrate. According to the method, a specially-made 4-MPy / MOF-coated silica gel adsorbent is adopted as a high-selectivity adsorbent, triple purification means of chlorine oxidation, zinc-loaded activated carbon and chelate resin are adopted, and a specially-made desorption solution is adopted, so that the total recovery rate of rhodium can reach 98% or above; and high-purity rhodium chloride hydrate with low impurity content is obtained.

Description

Technical Field

[0001] The invention relates to the field of chemical waste liquid recovery, and in particular to a method for recovering rhodium from rhodium-containing waste liquid to prepare hydrated rhodium trichloride. Background Art

[0002] Rhodium (Rh), a key member of the platinum group metals, is widely used in automotive exhaust catalysts, the electronics industry, chemical catalysis, and high-end alloys due to its excellent catalytic performance, high-temperature stability, and corrosion resistance. Global rhodium resources are extremely scarce and expensive, but rhodium-containing wastewater can contain up to 100-1000 ppm of rhodium, offering significant recovery potential. Therefore, recycling rhodium-containing wastewater (such as electroplating wastewater and spent catalyst leachate) is a key approach to alleviating resource shortages. For example, recovering rhodium trichloride hydrate from rhodium-containing wastewater can yield rhodium trichloride hydrate. Rhodium trichloride hydrate (RhCl₃·nH₂O) is a precursor for the synthesis of homogeneous catalysts, electroplating solutions, and nanomaterials. Its purity directly impacts the performance of downstream products. Therefore, efficient, low-cost, and green recovery processes are essential.

[0003] Traditional methods for recovering rhodium from spent rhodium catalysts primarily include adsorption separation, combustion, and oxidative digestion. Adsorption separation involves separating the rhodium from inorganic substances or ion exchange resins by adsorption. For example, Chinese Patent No. CN1452605A describes adsorbing rhodium onto an alkaline ion exchange resin and then calcining it to produce a rhodium-containing burnt ash. This method can only recover rhodium from hydroformylation reaction products, and only a portion of the rhodium is adsorbed onto the resin for recovery, making the resin non-recyclable. Combustion methods involve burning the spent catalyst liquid to remove organic components to recover rhodium. For example, Chinese Patent No. CN1088269A describes mixing a spent rhodium catalyst liquid containing an organic phosphine with a Group IA or IIA alkaline compound, then incinerating it at below 1000°C under air to recover rhodium, achieving a recovery rate of 93%-99%. However, this method requires the addition of a large amount of alkaline compound as a combustion inhibitor, and the formation of salts during the combustion process, including phosphates with phosphorus in the waste liquid, results in a large amount of rhodium ash, a low rhodium content, and a high level of impurities, complicating subsequent purification processes. Among them, the oxidation digestion method is to use inorganic acid and oxidant to oxidize and digest rhodium-containing organic waste liquid to separate rhodium and organic matter. For example, Chinese patent CN100575267A introduces a liquid phase method for recovering rhodium from waste rhodium catalyst in carbonyl synthesis, with a recovery rate of more than 97%. However, the processing efficiency of this method is relatively low, and the process involves high-temperature digestion. For many complex organic substances, the digestion will not be complete, affecting the recovery rate.

[0004] It can be seen that the traditional rhodium recovery process has more or less problems such as low recovery rate, serious impurity interference (such as coexistence of Pt, Pd, and Fe), and it is difficult to directly convert it into a high-value-added product, hydrated rhodium trichloride. Summary of the Invention

[0005] The invention aims to provide a method for recovering rhodium from rhodium-containing waste liquid to prepare rhodium trichloride hydrate, which solves the problems of low recovery rate and serious impurity interference in traditional rhodium recovery processes and prepares rhodium trichloride hydrate, a high-value-added product.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions: A method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid, comprising the steps of: S1. Wastewater pretreatment The rhodium-containing waste liquid is filtered to remove impurities, and then the pH is adjusted to 1-2 with hydrochloric acid. Coconut shell activated carbon accounting for 1-3% of the volume of the waste liquid is added to the waste liquid for stirring and adsorption, and then filtered to separate and remove the activated carbon; S2, Rhodium selective separation Prepare 4-MPy / MOF@silica gel adsorbent as a selective adsorbent, load the selective adsorbent into an adsorption column, dynamically adsorb rhodium-containing waste liquid, remove iron after adsorption, then circulate desorption with a desorption liquid, collect the rhodium-enriched liquid and evaporate and concentrate it to a rhodium concentration of ≥50 g / L; S3. Chlorination and purification The concentrated rhodium-enriched liquid is placed in a reactor, chlorine gas is introduced and the reaction is stirred, and then the rhodium-enriched liquid is subjected to secondary adsorption using zinc-loaded activated carbon. After adsorption, the rhodium-enriched liquid is subjected to ion exchange resin adsorption purification, and the rhodium liquid is collected after adsorption and evaporated to a rhodium concentration of ≥50 g / L; S4. Crystallization and post-processing The concentrated rhodium solution is placed in a container, and RhCl3·3H2O seed crystals accounting for 0.1-0.15% of the mass of the rhodium solution are added for reduced pressure crystallization. Finally, the crystals are washed with ethanol and vacuum dried to obtain hydrated rhodium trichloride.

[0007] A further improvement is that in step S1, the temperature of the stirring adsorption is 35-40°C, the rotation speed is 140-180 rpm, and the time is 50-60 min.

[0008] A further improvement is that in step S2, the specific operation of preparing 4-MPy / MOF@silica gel adsorbent is: (1) Silane pretreatment of silica gel: dissolve mesoporous silica gel in anhydrous toluene, add 3-chloropropyltriethoxysilane and triethylamine, stir and react at 100-110°C under nitrogen protection for 18-24 hours, then cool the reactant, wash and dry to obtain chloropropylated silica gel; (2) In situ growth of Zr-MOF film: dissolve zirconium tetrachloride in anhydrous ethanol, add phthalic acid and stir for 25-35 minutes, then add acetic acid dropwise to obtain a MOF precursor solution, then add the chloropropylated silica gel to the MOF precursor solution at a solid-liquid ratio of 1:8-10, and hydrothermally react in a sealed environment at a temperature of 70±1°C for 1.8-2.2 hours. The reactant is cooled, washed and dried to obtain MOF@silica gel; (3) 4-Mercaptopyridine grafting: Dissolve 4-mercaptopyridine in anhydrous ethanol, add anhydrous sodium carbonate and stir until it is clear to obtain a grafting solution. Then add MOF@silica gel to the grafting solution and stir the reaction at 60±2℃ under nitrogen protection for 6-8h. Then cool the reactant, wash and dry it to obtain 4-MPy / MOF@silica gel adsorbent.

[0009] A further improvement is that in step (1), the mass ratio of the mesoporous silica gel, 3-chloropropyltriethoxysilane, triethylamine and anhydrous toluene is 95-105:140-160:4-5:500; In step (2), the mass ratio of zirconium tetrachloride, phthalic acid, acetic acid and anhydrous ethanol is 3.1-3.3:2.4-2.6:1.2-1.3:200; In step (3), the mass ratio of 4-mercaptopyridine, anhydrous sodium carbonate, MOF@silica gel and anhydrous ethanol is 1.8-2:0.25-0.35:95-105:200.

[0010] A further improvement is that in step S2, the adsorption column adopts a φ50mm×300mm glass column, and the filling height is 25cm, the bed volume is 500mL, the dynamic adsorption flow rate is 1.8-2.2BV / h, and the adsorption is stopped when the rhodium concentration detected in the outlet liquid is ≤1ppm.

[0011] A further improvement is that in step S2, the iron removal refers to elution with an oxalic acid solution having a concentration of 0.1 M and a pH of 3±0.1, and the flow rate of the oxalic acid solution is 0.4-0.6 BV / h, and the total amount is 2-4 BV; The desorption liquid uses water as solvent and a mixture of 0.5-0.7M thiourea, 3-4M hydrochloric acid and 0.08-0.12M ascorbic acid as solute, and the desorption liquid flow rate is 0.4-0.8BV / h, and the total dosage is 2.5-3BV.

[0012] A further improvement is that in step S3, the flow rate of the chlorine gas is 100-120 mL / min, the temperature of the stirring reaction is 70-75° C., and the time is 3-5 h.

[0013] A further improvement is that in step S3, the ZnO loading in the zinc-loaded activated carbon is 4-6%, the amount of zinc-loaded activated carbon used is 0.5-0.8% of the volume of the rhodium-enriched solution, and the secondary adsorption temperature is 70-80°C and the time is 25-35 minutes.

[0014] A further improvement is that in step S3, the ion exchange resin adsorption purification uses Lewatit®MonoPlus TP214 chelating resin, and is filled into a φ50mm×400mm glass column with a filling height of 30cm, a bed volume of 250mL, an adsorption flow rate of 1-1.5BV / h, and adsorption is stopped when the heavy metal concentration of the outlet liquid is detected to be ≤1ppm.

[0015] A further improvement is that in step S4, the reduced pressure crystallization temperature is 35-40°C, the vacuum degree is -0.095 to -0.085 MPa, the stirring rate is 100-150 rpm, and the time is 80-120 min.

[0016] The beneficial effects of the present invention are: (1) The present invention uses a specially prepared 4-MPy / MOF@silica gel adsorbent as a highly selective adsorbent. Its silanization treatment can introduce amino groups on the silica gel surface, providing anchoring sites for subsequent functionalization. The thiol (-SH) group of 4-mercaptopyridine and the pyridine nitrogen atom can form a strong coordination bond with rhodium, which, combined with the size exclusion effect of the through-pores on the MOF mold, accurately achieves specific recognition and efficient adsorption of rhodium, and significantly inhibits the co-adsorption of other precious metals (such as Pt, Pd) and base metals (such as Fe, Cu); In addition, the present invention adopts a triple purification method of "chlorine oxidation + zinc-loaded activated carbon + chelating resin", wherein chlorine oxidation can convert low-valent rhodium species into soluble inert [RhCl6] 3- , unified rhodium chemical form, zinc-loaded activated carbon can selectively adsorb free chlorine and chlorine oxides to prevent subsequent equipment corrosion and impurity introduction, chelating resin contains thiourea groups, which can have highly selective adsorption and purification capabilities for heavy metals such as Pt, Pd, and Cu; The present invention also uses a special desorption liquid, in which high concentration of free thiourea (Tu) can destroy the Rh-pyridine bond to achieve desorption, while hydrochloric acid provides an acidic environment to prevent rhodium hydrolysis, and ascorbic acid can weaken the original strong coordination bond and prevent thiourea from oxidative failure, thereby ensuring the desorption rate; In summary: Through the high selectivity, mild desorption and low residue design of the adsorbent, the total rhodium recovery rate can reach more than 98%; the triple purification method and low-temperature crystallization technology can obtain high-purity hydrated rhodium trichloride with low impurity content, which meets the electronic grade RhCl3·3H2O standard.

[0017] (2) The present invention can also avoid the high energy consumption and product agglomeration problems caused by traditional high-temperature calcination; the use of ethanol washing instead of organic solvents can reduce the generation of hazardous waste, and the recycling rate of process wastewater can be ≥80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the surface SEM morphology of the 4-MPy / MOF@silica gel adsorbent in Example 2 of the present invention. DETAILED DESCRIPTION

[0019] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] 1. Main Materials Coconut shell activated carbon: KL5460 type, 12-16 mesh, purchased from Zhengzhou Kelin Water Purification Materials Co., Ltd. Mesoporous silica gel: pore size 12 ± 0.5 nm, purchased from Nanjing Pioneer Nanomaterials Co., Ltd. Thiourea: CH4N2S, purchased from Henan Haojin Chemical Products Co., Ltd. Ascorbic acid: purchased from Guangzhou Guangyu Biotechnology Co., Ltd. 3-Chloropropyltriethoxysilane: purchased from Dongguan Shanyi Plastics Co., Ltd. Zirconium tetrachloride: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. 4-Mercaptopyridine: purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd. Zinc-loaded activated carbon: loaded with ZnO, 12-16 mesh, purchased from Jiangsu Yiqing Activated Carbon Co., Ltd.

[0021] 2. Implementation of the Experiment The rhodium-containing organic waste liquid discharged from the olefin hydroformylation reaction system of a certain oil plant was taken as the treatment object of the following experimental groups. The main chemical composition of the rhodium-containing organic waste liquid is shown in Table 1 below: Table 1: Main chemical composition of rhodium-containing organic wastewater

[0022] Example 1 A method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid, comprising the steps of: S1. Wastewater pretreatment Take the rhodium-containing waste liquid, filter and remove impurities, adjust the pH to 1 with hydrochloric acid, add coconut shell activated carbon accounting for 1% of the waste liquid volume to the waste liquid for stirring and adsorption, the stirring adsorption temperature is 35°C, the speed is 140rpm, and the time is 60min, then filter and separate to remove the activated carbon.

[0023] S2, Rhodium selective separation Prepare 4-MPy / MOF@silica gel adsorbent as a selective adsorbent, and load the selective adsorbent into an adsorption column. The adsorption column adopts a φ50mm×300mm glass column, and the filling height is 25cm, the bed volume is 500mL, and the rhodium-containing waste liquid is dynamically adsorbed. The dynamic adsorption flow rate is 1.8BV / h, and the adsorption is stopped when the rhodium concentration of the outlet liquid is detected to be ≤1ppm. After adsorption, it is eluted with an oxalic acid solution with a concentration of 0.1M and a pH of 3, and the flow rate of the oxalic acid solution is 0.4BV / h, and the total amount is 2BV. Then, a desorption liquid is used for cyclic desorption, and the desorption liquid adopts a solvent of water, a solute of a mixture of 0.5M thiourea, 3M hydrochloric acid and 0.08M ascorbic acid, and the desorption liquid flow rate is 0.4BV / h, and the total amount is 3BV. The rhodium-enriched liquid is collected and evaporated (using a rotary evaporator, the same below) to a rhodium concentration of 50.80g / L; The specific operation of preparing 4-MPy / MOF@silica gel adsorbent is as follows: (1) Silane pretreatment of silica gel: mesoporous silica gel was dissolved in anhydrous toluene, 3-chloropropyltriethoxysilane and triethylamine were added, and the mixture was stirred at 100°C under nitrogen protection for 24 hours. The reactant was then cooled, washed and dried (the washing process can be performed by washing with ethanol, deionized water, etc. for multiple times, and the residual amount was detected by ICP-MS to avoid the introduction of new impurities, the same below) to obtain chloropropylated silica gel; the mass ratio of the mesoporous silica gel, 3-chloropropyltriethoxysilane, triethylamine and anhydrous toluene was 95:140:4:500; (2) In situ growth of Zr-MOF film: zirconium tetrachloride was dissolved in anhydrous ethanol, phthalic acid was added and stirred for 25 min, and acetic acid was added dropwise to obtain a MOF precursor solution. The chloropropylated silica gel was added to the MOF precursor solution at a solid-liquid ratio of 1:8, and the mixture was hydrothermally reacted in a sealed environment at a temperature of 70±1°C for 1.8 h. The reactant was cooled, washed and dried to obtain MOF@silica gel; the mass ratio of zirconium tetrachloride, phthalic acid, acetic acid and anhydrous ethanol was 3.1:2.4:1.2:200; (3) 4-Mercaptopyridine grafting: 4-Mercaptopyridine was dissolved in anhydrous ethanol, and anhydrous sodium carbonate was added and stirred until it was clarified to obtain a grafting solution. MOF@silica gel was then added to the grafting solution, and the mixture was stirred and reacted at 60±2°C under nitrogen protection for 6 h. The reactant was then cooled, washed, and dried to obtain a 4-MPy / MOF@silica gel adsorbent. The mass ratio of 4-mercaptopyridine, anhydrous sodium carbonate, MOF@silica gel, and anhydrous ethanol was 1.8:0.25:95:200.

[0024] S3. Chlorination and purification The concentrated rhodium-enriched liquid was placed in a reactor, chlorine was introduced at a flow rate of 100 mL / min and stirred for reaction, the temperature was 70°C, and the time was 5 h. Then, the rhodium-enriched liquid was subjected to secondary adsorption with zinc-loaded activated carbon (ZnO loading was 4%). The amount of zinc-loaded activated carbon was 0.5% of the volume of the rhodium-enriched liquid, and the secondary adsorption temperature was 70°C for 35 min. After adsorption, the rhodium-enriched liquid was purified by ion exchange resin adsorption. Lewatit® MonoPlus TP214 chelating resin was used and filled into a φ50 mm × 400 mm glass column with a filling height of 30 cm and a bed volume of 250 mL. The adsorption flow rate was 1 BV / h, and the adsorption was stopped when the heavy metal concentration of the outlet liquid was detected to be ≤1 ppm. After adsorption, the rhodium liquid was collected and evaporated to a rhodium concentration of 50.18 g / L.

[0025] S4. Crystallization and post-processing The concentrated rhodium solution was placed in a container, and RhCl3·3H2O seed crystals accounting for 0.1% of the mass of the rhodium solution were added for vacuum crystallization. The vacuum crystallization temperature was 35°C, the vacuum degree was -0.095 MPa, the stirring rate was 100 rpm, and the time was 120 min. Finally, the crystals were washed with ethanol and vacuum dried to obtain hydrated rhodium trichloride.

[0026] Example 2 A method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid, comprising the steps of: S1. Wastewater pretreatment The rhodium-containing waste liquid was filtered to remove impurities and then adjusted to pH 1.5 with hydrochloric acid. Coconut shell activated carbon accounting for 2% of the volume of the waste liquid was added to the waste liquid for stirring and adsorption. The stirring and adsorption temperature was 38°C, the rotation speed was 160 rpm, and the time was 55 minutes. The activated carbon was then filtered and separated to remove it.

[0027] S2, Rhodium selective separation Prepare 4-MPy / MOF@silica gel adsorbent as a selective adsorbent, and load the selective adsorbent into an adsorption column. The adsorption column adopts a φ50mm×300mm glass column, and the filling height is 25cm, the bed volume is 500mL, and the rhodium-containing waste liquid is dynamically adsorbed. The dynamic adsorption flow rate is 2BV / h, and the adsorption is stopped when the outlet liquid detects the rhodium concentration ≤1ppm. After adsorption, it is eluted with an oxalic acid solution with a concentration of 0.1M and a pH of 3, and the oxalic acid solution flow rate is 0.5BV / h, and the total amount is 3BV. Then, a desorption liquid is used for cyclic desorption, and the desorption liquid adopts a solvent of water, a solute of a mixture of 0.6M thiourea, 3.5M hydrochloric acid and 0.1M ascorbic acid, and the desorption liquid flow rate is 0.6BV / h, and the total amount is 2.8BV. The rhodium-enriched liquid is collected and evaporated and concentrated to a rhodium concentration of 50.43g / L; The specific operation of preparing 4-MPy / MOF@silica gel adsorbent is as follows: (1) Silane pretreatment of silica gel: mesoporous silica gel was dissolved in anhydrous toluene, 3-chloropropyltriethoxysilane and triethylamine were added, and the mixture was stirred and reacted at 105°C under nitrogen protection for 20 hours. The reactant was then cooled, washed and dried to obtain chloropropylated silica gel; the mass ratio of the mesoporous silica gel, 3-chloropropyltriethoxysilane, triethylamine and anhydrous toluene was 100:150:4.5:500; (2) In situ growth of Zr-MOF film: zirconium tetrachloride was dissolved in anhydrous ethanol, phthalic acid was added and stirred for 30 min, and acetic acid was added dropwise to obtain a MOF precursor solution. The chloropropylated silica gel was added to the MOF precursor solution at a solid-liquid ratio of 1:9, and the mixture was hydrothermally reacted in a sealed environment at a temperature of 70±1°C for 2 h. The reactant was cooled, washed and dried to obtain MOF@silica gel; the mass ratio of zirconium tetrachloride, phthalic acid, acetic acid and anhydrous ethanol was 3.2:2.5:1.25:200; (3) 4-Mercaptopyridine grafting: 4-Mercaptopyridine was dissolved in anhydrous ethanol, and anhydrous sodium carbonate was added and stirred until it was clarified to obtain a grafting solution. MOF@silica gel was then added to the grafting solution, and the mixture was stirred and reacted at 60±2°C under nitrogen protection for 7 h. The reactant was then cooled, washed, and dried to obtain a 4-MPy / MOF@silica gel adsorbent. The mass ratio of the 4-mercaptopyridine, anhydrous sodium carbonate, MOF@silica gel, and anhydrous ethanol was 1.9:0.3:100:200.

[0028] The microstructure of the 4-MPy / MOF@silica gel adsorbent was analyzed using a Hitachi SU5000 scanning electron microscope (SEM) with an accelerating voltage of 5 kV and a working distance of approximately 5 mm. Figure 1As shown in the figure, it can be seen that the surface of the 4-MPy / MOF@silica gel adsorbent is basically covered by the Zr-MOF film, and the Zr-MOF film particles are evenly arranged to form a large number of nanopores (the pore size distribution is between 0.7-0.9 nm according to the density functional theory method). This allows 4-mercaptopyridine to diffuse into the pores and the pores of the internal mesoporous silica gel to complete the grafting and allow Rh to be adsorbed during the dynamic adsorption process. 3+ Pass, while blocking [PdCl4] 2- and [PtCl4] 2- , to achieve efficient selection.

[0029] S3. Chlorination and purification The concentrated rhodium-enriched liquid was placed in a reactor, chlorine was introduced at a flow rate of 110 mL / min and the reaction was stirred at a temperature of 72°C for 4 hours. The rhodium-enriched liquid was then subjected to secondary adsorption with zinc-loaded activated carbon (ZnO loading of 5%). The amount of zinc-loaded activated carbon was 0.6% of the volume of the rhodium-enriched liquid, and the secondary adsorption temperature was 75°C for 30 minutes. After adsorption, the rhodium-enriched liquid was purified by ion exchange resin adsorption using Lewatit® MonoPlus TP214 chelating resin, which was loaded into a φ50 mm × 400 mm glass column with a filling height of 30 cm and a bed volume of 250 mL. The adsorption flow rate was 1.2 BV / h, and the adsorption was stopped when the heavy metal concentration of the outlet liquid was detected to be ≤1 ppm. After adsorption, the rhodium liquid was collected and evaporated to a rhodium concentration of 50.23 g / L.

[0030] S4. Crystallization and post-processing The concentrated rhodium solution was placed in a container, and RhCl3·3H2O seed crystals accounting for 0.12% of the mass of the rhodium solution were added for vacuum crystallization. The vacuum crystallization temperature was 38°C, the vacuum degree was -0.09 MPa, the stirring rate was 120 rpm, and the time was 100 min. Finally, the crystals were washed with ethanol and vacuum dried to obtain hydrated rhodium trichloride.

[0031] Example 3 A method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid, comprising the steps of: S1. Wastewater pretreatment Take the rhodium-containing waste liquid, filter and remove impurities, adjust the pH to 2 with hydrochloric acid, add coconut shell activated carbon accounting for 3% of the waste liquid volume to the waste liquid for stirring and adsorption, the stirring adsorption temperature is 40°C, the speed is 180 rpm, and the time is 50 minutes, then filter and separate to remove the activated carbon.

[0032] S2, Rhodium selective separation Prepare 4-MPy / MOF@silica gel adsorbent as a selective adsorbent, and load the selective adsorbent into an adsorption column. The adsorption column adopts a φ50mm×300mm glass column, and the filling height is 25cm, the bed volume is 500mL, and the rhodium-containing waste liquid is dynamically adsorbed. The dynamic adsorption flow rate is 2.2BV / h, and the adsorption is stopped when the outlet liquid detects the rhodium concentration ≤1ppm. After adsorption, it is eluted with an oxalic acid solution with a concentration of 0.1M and a pH of 3, and the oxalic acid solution flow rate is 0.6BV / h, and the total amount is 4BV. Then, a desorption liquid is used for cyclic desorption, and the desorption liquid adopts a solvent of water, a solute of 0.7M thiourea, 4M hydrochloric acid and 0.12M ascorbic acid mixed solution, and the desorption liquid flow rate is 0.8BV / h, and the total amount is 2.5BV. The rhodium-enriched liquid is collected and evaporated and concentrated to a rhodium concentration of 50.55g / L; The specific operation of preparing 4-MPy / MOF@silica gel adsorbent is as follows: (1) Silane pretreatment of silica gel: mesoporous silica gel was dissolved in anhydrous toluene, 3-chloropropyltriethoxysilane and triethylamine were added, and the mixture was stirred and reacted at 110°C under nitrogen protection for 18 hours. The reactant was then cooled, washed and dried to obtain chloropropylated silica gel; the mass ratio of the mesoporous silica gel, 3-chloropropyltriethoxysilane, triethylamine and anhydrous toluene was 105:160:5:500; (2) In situ growth of Zr-MOF film: zirconium tetrachloride was dissolved in anhydrous ethanol, phthalic acid was added and stirred for 35 min, and acetic acid was added dropwise to obtain a MOF precursor solution. The chloropropylated silica gel was added to the MOF precursor solution at a solid-liquid ratio of 1:10, and the mixture was hydrothermally reacted in a sealed environment at a temperature of 70±1°C for 2.2 h. The reactant was cooled, washed and dried to obtain MOF@silica gel; the mass ratio of zirconium tetrachloride, phthalic acid, acetic acid and anhydrous ethanol was 3.3:2.6:1.3:200; (3) 4-Mercaptopyridine grafting: 4-Mercaptopyridine was dissolved in anhydrous ethanol, and anhydrous sodium carbonate was added and stirred until it was clarified to obtain a grafting solution. MOF@silica gel was then added to the grafting solution, and the mixture was stirred and reacted at 60±2°C under nitrogen protection for 8 h. The reactant was then cooled, washed, and dried to obtain a 4-MPy / MOF@silica gel adsorbent; the mass ratio of the 4-mercaptopyridine, anhydrous sodium carbonate, MOF@silica gel, and anhydrous ethanol was 2:0.35:105:200.

[0033] S3. Chlorination and purification The concentrated rhodium-enriched liquid was placed in a reactor, chlorine was introduced at a flow rate of 120 mL / min and stirred for reaction, the temperature was 75°C, and the time was 3 h. Then, the rhodium-enriched liquid was subjected to secondary adsorption with zinc-loaded activated carbon (ZnO loading was 6%). The amount of zinc-loaded activated carbon was 0.8% of the volume of the rhodium-enriched liquid, and the secondary adsorption temperature was 80°C for 25 min. After adsorption, the rhodium-enriched liquid was purified by ion exchange resin adsorption using Lewatit® MonoPlus TP214 chelating resin, which was loaded into a φ50 mm × 400 mm glass column with a filling height of 30 cm and a bed volume of 250 mL. The adsorption flow rate was 1.5 BV / h, and the adsorption was stopped when the heavy metal concentration of the outlet liquid was detected to be ≤1 ppm. After adsorption, the rhodium liquid was collected and evaporated to a rhodium concentration of 50.91 g / L.

[0034] S4. Crystallization and post-processing The concentrated rhodium solution was placed in a container, and RhCl3·3H2O seed crystals accounting for 0.15% of the mass of the rhodium solution were added for vacuum crystallization. The vacuum crystallization temperature was 40°C, the vacuum degree was -0.085MPa, the stirring rate was 150rpm, and the time was 80min. Finally, the crystals were washed with ethanol and vacuum dried to obtain hydrated rhodium trichloride.

[0035] Comparative Example 1 A method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid, comprising the steps of: S1. Wastewater pretreatment The rhodium-containing waste liquid was filtered to remove impurities and then adjusted to pH 1.5 with hydrochloric acid. Coconut shell activated carbon accounting for 2% of the volume of the waste liquid was added to the waste liquid for stirring and adsorption. The stirring and adsorption temperature was 38°C, the rotation speed was 160 rpm, and the time was 55 minutes. The activated carbon was then filtered and separated to remove it.

[0036] S2, Rhodium selective separation Prepare 4-MPy@ silica gel adsorbent as a selective adsorbent, and the selective adsorbent is loaded into an adsorption column. The adsorption column adopts a φ50mm×300mm glass column, and the filling height is 25cm, the bed volume is 500mL, and the rhodium-containing waste liquid is dynamically adsorbed. The flow rate of dynamic adsorption is 2BV / h, and adsorption is stopped when the outlet liquid detects rhodium concentration ≤1ppm. After adsorption, it is eluted with an oxalic acid solution with a concentration of 0.1M and a pH of 3, and the oxalic acid solution flow rate is 0.5BV / h, and the total consumption is 3BV. Then, a desorption liquid is used for cyclic desorption. The desorption liquid adopts water as the solvent, and the solute is a mixed solution of 0.6M thiourea, 3.5M hydrochloric acid and 0.1M ascorbic acid, and the desorption liquid flow rate is 0.6BV / h, and the total consumption is 2.8BV. The rhodium-enriched liquid is collected and evaporated and concentrated to a rhodium concentration of 50.52g / L; The specific operation of preparing 4-MPy@silica gel adsorbent is as follows: (1) Silane pretreatment of silica gel: mesoporous silica gel was dissolved in anhydrous toluene, 3-chloropropyltriethoxysilane and triethylamine were added, and the mixture was stirred and reacted at 105°C under nitrogen protection for 20 hours. The reactant was then cooled, washed and dried to obtain chloropropylated silica gel; the mass ratio of the mesoporous silica gel, 3-chloropropyltriethoxysilane, triethylamine and anhydrous toluene was 100:150:4.5:500; (2) 4-Mercaptopyridine grafting: 4-Mercaptopyridine was dissolved in anhydrous ethanol, and anhydrous sodium carbonate was added and stirred until it was clarified to obtain a grafting solution. Chloropropylated silica gel was then added to the grafting solution, and the mixture was stirred and reacted at 60±2°C under nitrogen protection for 7 h. The reactant was then cooled, washed, and dried to obtain 4-MPy@silica gel adsorbent; the mass ratio of the 4-mercaptopyridine, anhydrous sodium carbonate, chloropropylated silica gel, and anhydrous ethanol was 1.9:0.3:100:200.

[0037] S3. Chlorination and purification The concentrated rhodium-enriched liquid was placed in a reactor, chlorine was introduced at a flow rate of 110 mL / min and the reaction was stirred at a temperature of 72°C for 4 hours. The rhodium-enriched liquid was then subjected to secondary adsorption with zinc-loaded activated carbon (ZnO loading of 5%). The amount of zinc-loaded activated carbon was 0.6% of the volume of the rhodium-enriched liquid, and the secondary adsorption temperature was 75°C for 30 minutes. After adsorption, the rhodium-enriched liquid was purified by ion exchange resin adsorption using Lewatit® MonoPlus TP214 chelating resin, which was loaded into a φ50 mm × 400 mm glass column with a filling height of 30 cm and a bed volume of 250 mL. The adsorption flow rate was 1.2 BV / h, and the adsorption was stopped when the heavy metal concentration of the outlet liquid was detected to be ≤1 ppm. After adsorption, the rhodium liquid was collected and evaporated to a rhodium concentration of 50.29 g / L.

[0038] S4. Crystallization and post-processing The concentrated rhodium solution was placed in a container, and RhCl3·3H2O seed crystals accounting for 0.12% of the mass of the rhodium solution were added for vacuum crystallization. The vacuum crystallization temperature was 38°C, the vacuum degree was -0.09 MPa, the stirring rate was 120 rpm, and the time was 100 min. Finally, the crystals were washed with ethanol and vacuum dried to obtain hydrated rhodium trichloride.

[0039] Comparative Example 2 A method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid, comprising the steps of: S1. Wastewater pretreatment The rhodium-containing waste liquid was filtered to remove impurities and then adjusted to pH 1.5 with hydrochloric acid. Coconut shell activated carbon accounting for 2% of the volume of the waste liquid was added to the waste liquid for stirring and adsorption. The stirring and adsorption temperature was 38°C, the rotation speed was 160 rpm, and the time was 55 minutes. The activated carbon was then filtered and separated to remove it.

[0040] S2, Rhodium selective separation Prepare MOF / 4-MPy@silica gel adsorbent as a selective adsorbent, and load the selective adsorbent into an adsorption column. The adsorption column adopts a φ50mm×300mm glass column, and the filling height is 25cm, the bed volume is 500mL, and the rhodium-containing waste liquid is dynamically adsorbed. The dynamic adsorption flow rate is 2BV / h, and the adsorption is stopped when the rhodium concentration of the outlet liquid is detected to be ≤1ppm. After adsorption, it is eluted with an oxalic acid solution with a concentration of 0.1M and a pH of 3, and the flow rate of the oxalic acid solution is 0.5BV / h, and the total amount is 3BV. Then, a desorption liquid is used for cyclic desorption, and the desorption liquid adopts a solvent of water, a solute of a mixture of 0.6M thiourea, 3.5M hydrochloric acid and 0.1M ascorbic acid, and the desorption liquid flow rate is 0.6BV / h, and the total amount is 2.8BV. The rhodium-enriched liquid is collected and evaporated and concentrated to a rhodium concentration of 50.37g / L; The specific operation of preparing MOF / 4-MPy@silica gel adsorbent is as follows: (1) Silane pretreatment of silica gel: mesoporous silica gel was dissolved in anhydrous toluene, 3-chloropropyltriethoxysilane and triethylamine were added, and the mixture was stirred and reacted at 105°C under nitrogen protection for 20 hours. The reactant was then cooled, washed and dried to obtain chloropropylated silica gel; the mass ratio of the mesoporous silica gel, 3-chloropropyltriethoxysilane, triethylamine and anhydrous toluene was 100:150:4.5:500; (2) 4-mercaptopyridine grafting: 4-mercaptopyridine was dissolved in anhydrous ethanol, and anhydrous sodium carbonate was added and stirred until clarified to obtain a grafting solution. Chloropropylated silica gel was then added to the grafting solution, and the mixture was stirred and reacted at 60±2°C under nitrogen protection for 7 h. The reactant was then cooled, washed, and dried to obtain 4-MPy@silica gel. The mass ratio of 4-mercaptopyridine, anhydrous sodium carbonate, MOF@silica gel, and anhydrous ethanol was 1.9:0.3:100:200. (3) In situ growth of Zr-MOF film: zirconium tetrachloride was dissolved in anhydrous ethanol, phthalic acid was added and stirred for 30 min, and acetic acid was added dropwise to obtain a MOF precursor solution. The 4-MPy@silica gel was added to the MOF precursor solution at a solid-liquid ratio of 1:9, and the mixture was hydrothermally reacted in a sealed environment at a temperature of 70±1°C for 2 h. The reactant was cooled, washed and dried to obtain a MOF / 4-MPy@silica gel adsorbent; the mass ratio of zirconium tetrachloride, phthalic acid, acetic acid and anhydrous ethanol was 3.2:2.5:1.25:200.

[0041] S3. Chlorination and purification The concentrated rhodium-enriched liquid was placed in a reactor, chlorine was introduced at a flow rate of 110 mL / min and stirred for reaction, the temperature was 72 ° C, and the time was 4 h. Then, the rhodium-enriched liquid was subjected to secondary adsorption with zinc-loaded activated carbon (ZnO loading was 5%). The amount of zinc-loaded activated carbon was 0.6% of the volume of the rhodium-enriched liquid, and the secondary adsorption temperature was 75 ° C for 30 min. After adsorption, the rhodium-enriched liquid was purified by ion exchange resin adsorption using Lewatit® MonoPlus TP214 chelating resin, and filled into a φ50 mm × 400 mm glass column with a filling height of 30 cm and a bed volume of 250 mL. The adsorption flow rate was 1.2 BV / h, and the adsorption was stopped when the heavy metal concentration of the outlet liquid was detected to be ≤1 ppm. After adsorption, the rhodium liquid was collected and evaporated to a rhodium concentration of 50.08 g / L.

[0042] S4. Crystallization and post-processing The concentrated rhodium solution was placed in a container, and RhCl3·3H2O seed crystals accounting for 0.12% of the mass of the rhodium solution were added for vacuum crystallization. The vacuum crystallization temperature was 38°C, the vacuum degree was -0.09 MPa, the stirring rate was 120 rpm, and the time was 100 min. Finally, the crystals were washed with ethanol and vacuum dried to obtain hydrated rhodium trichloride.

[0043] Comparative Example 3 A method for preparing rhodium trichloride hydrate by recovering rhodium from rhodium-containing waste liquid, comprising the steps of: S1. Wastewater pretreatment The rhodium-containing waste liquid was filtered to remove impurities and then adjusted to pH 1.5 with hydrochloric acid. Coconut shell activated carbon accounting for 2% of the volume of the waste liquid was added to the waste liquid for stirring and adsorption. The stirring and adsorption temperature was 38°C, the rotation speed was 160 rpm, and the time was 55 minutes. The activated carbon was then filtered and separated to remove it.

[0044] S2, Rhodium selective separation Prepare 4-MPy / MOF@silica gel adsorbent as a selective adsorbent, and load the selective adsorbent into an adsorption column. The adsorption column adopts a φ50mm×300mm glass column, and the filling height is 25cm, the bed volume is 500mL, and the rhodium-containing waste liquid is dynamically adsorbed. The dynamic adsorption flow rate is 2BV / h, and the adsorption is stopped when the rhodium concentration of the outlet liquid is detected to be ≤1ppm. After adsorption, it is eluted with an oxalic acid solution with a concentration of 0.1M and a pH of 3, and the flow rate of the oxalic acid solution is 0.5BV / h, and the total amount is 3BV. Then, a desorption liquid is used for cyclic desorption, and the desorption liquid adopts a solvent of water, a solute of a mixed solution of 0.6M thiourea and 3.5M hydrochloric acid, and the desorption liquid flow rate is 0.6BV / h, and the total amount is 2.8BV. The rhodium-enriched liquid is collected and evaporated and concentrated to a rhodium concentration of 50.49g / L; The specific operation of preparing 4-MPy / MOF@silica gel adsorbent is as follows: (1) Silane pretreatment of silica gel: mesoporous silica gel was dissolved in anhydrous toluene, 3-chloropropyltriethoxysilane and triethylamine were added, and the mixture was stirred and reacted at 105°C under nitrogen protection for 20 hours. The reactant was then cooled, washed and dried to obtain chloropropylated silica gel; the mass ratio of the mesoporous silica gel, 3-chloropropyltriethoxysilane, triethylamine and anhydrous toluene was 100:150:4.5:500; (2) In situ growth of Zr-MOF film: zirconium tetrachloride was dissolved in anhydrous ethanol, phthalic acid was added and stirred for 30 min, and acetic acid was added dropwise to obtain a MOF precursor solution. The chloropropylated silica gel was added to the MOF precursor solution at a solid-liquid ratio of 1:9, and the mixture was hydrothermally reacted in a sealed environment at a temperature of 70±1°C for 2 h. The reactant was cooled, washed and dried to obtain MOF@silica gel; the mass ratio of zirconium tetrachloride, phthalic acid, acetic acid and anhydrous ethanol was 3.2:2.5:1.25:200; (3) 4-Mercaptopyridine grafting: 4-Mercaptopyridine was dissolved in anhydrous ethanol, and anhydrous sodium carbonate was added and stirred until it was clarified to obtain a grafting solution. MOF@silica gel was then added to the grafting solution, and the mixture was stirred and reacted at 60±2°C under nitrogen protection for 7 h. The reactant was then cooled, washed, and dried to obtain a 4-MPy / MOF@silica gel adsorbent. The mass ratio of the 4-mercaptopyridine, anhydrous sodium carbonate, MOF@silica gel, and anhydrous ethanol was 1.9:0.3:100:200.

[0045] S3. Chlorination and purification The concentrated rhodium-enriched liquid was placed in a reactor, chlorine was introduced at a flow rate of 110 mL / min and the reaction was stirred at a temperature of 72°C for 4 hours. The rhodium-enriched liquid was then subjected to secondary adsorption with zinc-loaded activated carbon (ZnO loading of 5%). The amount of zinc-loaded activated carbon was 0.6% of the volume of the rhodium-enriched liquid, and the secondary adsorption temperature was 75°C for 30 minutes. After adsorption, the rhodium-enriched liquid was purified by ion exchange resin adsorption using Lewatit® MonoPlus TP214 chelating resin, which was loaded into a φ50 mm × 400 mm glass column with a filling height of 30 cm and a bed volume of 250 mL. The adsorption flow rate was 1.2 BV / h, and the adsorption was stopped when the heavy metal concentration of the outlet liquid was detected to be ≤1 ppm. After adsorption, the rhodium liquid was collected and evaporated to a rhodium concentration of 50.13 g / L.

[0046] S4. Crystallization and post-processing The concentrated rhodium solution was placed in a container, and RhCl3·3H2O seed crystals accounting for 0.12% of the mass of the rhodium solution were added for vacuum crystallization. The vacuum crystallization temperature was 38°C, the vacuum degree was -0.09 MPa, the stirring rate was 120 rpm, and the time was 100 min. Finally, the crystals were washed with ethanol and vacuum dried to obtain hydrated rhodium trichloride.

[0047] 3. Performance Testing According to the process routes of Examples 1-3 and Comparative Examples 1-3, respectively, the recovery of rhodium in rhodium-containing organic waste liquid was finally achieved, and a reddish-brown powdery hydrated rhodium trichloride was prepared. The rhodium recovery rate of each group, the rhodium content in the hydrated rhodium trichloride, and the metal impurity content were analyzed and detected, as follows: (1) The rhodium recovery rate is calculated as follows:

[0048] Among them, the mass proportion of rhodium in hydrated rhodium trichloride was obtained by weight analysis, and the mass proportion of rhodium in the waste liquid was obtained by inductively coupled plasma optical emission spectrometry (IPC-OES).

[0049] (2) With reference to the standard "YS / T 593-2006 Hydrated Rhodium Trichloride", the content of Pd, Pt, Fe, Na and Cu metal impurities in hydrated rhodium trichloride was tested and its grade was determined according to Table 2 below: Table 2: Mass fraction of impurity elements

[0050] (3) With reference to GBT1485-1979 Chemical Analysis Methods for Platinum-Rhodium Alloys, determine the rhodium content in hydrated rhodium trichloride to determine whether it meets the industry standard of 38.0-42.0%.

[0051] 4. Results Analysis According to statistics, the results of the rhodium recovery rate, rhodium content in hydrated rhodium trichloride, and metal impurity content of the above-mentioned groups are shown in Table 3 below: Table 3: Test results

[0052] As can be seen from Table 3 above, the recovery process adopted in Examples 1-3 of the present invention has a rhodium recovery rate of more than 98.02%, an impurity content of less than 0.017%, a high purity, and can reach first-class quality. The rhodium content in the hydrated rhodium trichloride is stabilized between 38-39%, meeting industry standards, especially the rhodium content of Example 2 is substantially close to the rhodium content of pure RhCl3·3H2O. Comparative Examples 1-3 are all adjustments made on the basis of Example 2, wherein: Comparative Example 1 omits the step of in situ growth of Zr-MOF film when preparing the selective adsorbent, which causes it to lose the size exclusion effect, resulting in an increase in impurities, especially Pd and Pt impurities coexisting with Ph3, and the content is significantly increased, and the quality of the final hydrated rhodium trichloride cannot reach the secondary standard, and the rhodium content is also slightly lower than the industry standard. At the same time, due to impurity competition, the dynamic adsorption of rhodium is affected to a certain extent, so that the rhodium recovery rate is reduced to 91.49%; Comparative Example 2, when preparing the selective adsorbent, swaps the in situ growth of Zr-MOF film and the 4-mercaptopyridine grafting steps, resulting in a significant increase in final impurities, the quality of hydrated rhodium trichloride is reduced to secondary, and the rhodium recovery rate is also reduced. Analysis shows that the reason may be that the first grafting makes 4-MPy basically fill the silica gel surface and pores, which affects the uniform nucleation growth of MOF. In addition, the 4-MPy part is mixed with the MOF precursor (Zr 4+ / BDC) coordination, which affected the functional groups; in the comparative example, when using the desorption solution, the ascorbic acid component was removed, which reduced the stability of the desorption effect, and ultimately manifested in a large loss of rhodium and a significant decrease in the recovery rate to 86.64%.

[0053] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A method for preparing hydrated rhodium trichloride by recovering rhodium from rhodium-containing waste liquid, characterized in that the steps include: S1. Wastewater pretreatment The rhodium-containing waste liquid is filtered to remove impurities, and then the pH is adjusted to 1-2 with hydrochloric acid. Coconut shell activated carbon accounting for 1-3% of the volume of the waste liquid is added to the waste liquid for stirring and adsorption, and then filtered to separate and remove the activated carbon; S2, Rhodium selective separation Prepare 4-MPy / MOF@silica gel adsorbent as a selective adsorbent, load the selective adsorbent into an adsorption column, dynamically adsorb rhodium-containing waste liquid, remove iron after adsorption, then circulate desorption with a desorption liquid, collect the rhodium-enriched liquid and evaporate and concentrate it to a rhodium concentration of ≥50 g / L; S3. Chlorination and purification The concentrated rhodium-enriched liquid is placed in a reactor, chlorine gas is introduced and the reaction is stirred, and then the rhodium-enriched liquid is subjected to secondary adsorption using zinc-loaded activated carbon. After adsorption, the rhodium-enriched liquid is subjected to ion exchange resin adsorption purification, and the rhodium liquid is collected after adsorption and evaporated to a rhodium concentration of ≥50 g / L; S4. Crystallization and post-processing The concentrated rhodium solution is placed in a container, and RhCl3·3H2O seed crystals accounting for 0.1-0.15% of the mass of the rhodium solution are added for reduced pressure crystallization. Finally, the crystals are washed with ethanol and vacuum dried to obtain hydrated rhodium trichloride.

2. a kind of method of reclaiming rhodium and preparing hydrated rhodium trichloride from rhodium-containing waste liquid according to claim 1, is characterized in that, In step S1, the stirring adsorption is carried out at a temperature of 35-40° C., a rotation speed of 140-180 rpm, and a time of 50-60 min.

3. a kind of method of reclaiming rhodium and preparing hydrated Rhodium Trichloride from rhodium-containing waste liquid according to claim 1, is characterized in that, In step S2, the specific operation of preparing 4-MPy / MOF@silica gel adsorbent is as follows: (1) Silane pretreatment of silica gel: dissolve mesoporous silica gel in anhydrous toluene, add 3-chloropropyltriethoxysilane and triethylamine, stir and react at 100-110°C under nitrogen protection for 18-24 hours, then cool the reactant, wash and dry to obtain chloropropylated silica gel; (2) In situ growth of Zr-MOF film: dissolve zirconium tetrachloride in anhydrous ethanol, add phthalic acid and stir for 25-35 minutes, then add acetic acid dropwise to obtain a MOF precursor solution, then add the chloropropylated silica gel to the MOF precursor solution at a solid-liquid ratio of 1:8-10, and hydrothermally react in a sealed environment at a temperature of 70±1°C for 1.8-2.2 hours. The reactant is cooled, washed and dried to obtain MOF@silica gel; (3) 4-Mercaptopyridine grafting: Dissolve 4-mercaptopyridine in anhydrous ethanol, add anhydrous sodium carbonate and stir until it is clear to obtain a grafting solution. Then add MOF@silica gel to the grafting solution and stir the reaction at 60±2℃ under nitrogen protection for 6-8h. Then cool the reactant, wash and dry it to obtain 4-MPy / MOF@silica gel adsorbent.

4. a kind of method of reclaiming rhodium and preparing hydrated rhodium trichloride from rhodium-containing waste liquid according to claim 3, is characterized in that, In step (1), the mass ratio of the mesoporous silica gel, 3-chloropropyltriethoxysilane, triethylamine and anhydrous toluene is 95-105:140-160:4-5:500; In step (2), the mass ratio of zirconium tetrachloride, phthalic acid, acetic acid and anhydrous ethanol is 3.1-3.3:2.4-2.6:1.2-1.3:200; In step (3), the mass ratio of 4-mercaptopyridine, anhydrous sodium carbonate, MOF@silica gel and anhydrous ethanol is 1.8-2:0.25-0.35:95-105:

200.

5. a kind of method of reclaiming rhodium and preparing hydrated Rhodium Chloride from rhodium-containing waste liquid according to claim 1, is characterized in that, In step S2, the adsorption column adopts a φ50mm×300mm glass column, and the filling height is 25cm, the bed volume is 500mL, the dynamic adsorption flow rate is 1.8-2.2BV / h, and the adsorption is stopped when the rhodium concentration of the outlet liquid is detected to be ≤1ppm.

6. a kind of method of reclaiming rhodium and preparing hydrated rhodium trichloride from rhodium-containing waste liquid according to claim 1, is characterized in that, In step S2, the iron removal refers to elution with an oxalic acid solution having a concentration of 0.1 M and a pH of 3±0.1, and the flow rate of the oxalic acid solution is 0.4-0.6 BV / h, and the total amount is 2-4 BV; The desorption liquid uses water as solvent and a mixture of 0.5-0.7M thiourea, 3-4M hydrochloric acid and 0.08-0.12M ascorbic acid as solute, and the desorption liquid flow rate is 0.4-0.8BV / h, and the total dosage is 2.5-3BV.

7. a kind of method of reclaiming rhodium and preparing hydrated Rhodium Trichloride from rhodium-containing waste liquid according to claim 1, is characterized in that, In step S3, the flow rate of the chlorine gas is 100-120 mL / min, the temperature of the stirring reaction is 70-75° C., and the time is 3-5 h.

8. a kind of method of reclaiming rhodium and preparing hydrated Rhodium Chloride from rhodium-containing waste liquid according to claim 1, is characterized in that, In step S3, the ZnO loading in the zinc-loaded activated carbon is 4-6%, the amount of zinc-loaded activated carbon used is 0.5-0.8% of the volume of the rhodium-enriched solution, and the secondary adsorption temperature is 70-80° C., and the time is 25-35 min.

9. a kind of method of reclaiming rhodium and preparing hydrated Rhodium Chloride from rhodium-containing waste liquid according to claim 1, is characterized in that, In step S3, the ion exchange resin adsorption purification uses Lewatit® MonoPlus TP214 chelating resin and is filled into a φ50mm×400mm glass column with a filling height of 30cm, a bed volume of 250mL, an adsorption flow rate of 1-1.5BV / h, and adsorption is stopped when the heavy metal concentration detected in the outlet liquid is ≤1ppm.

10. a kind of method of reclaiming rhodium and preparing hydrated Rhodium Chloride from rhodium-containing waste liquid according to claim 1, is characterized in that, In step S4, the reduced pressure crystallization temperature is 35-40° C., the vacuum degree is -0.095 to -0.085 MPa, the stirring rate is 100-150 rpm, and the time is 80-120 min.

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