Method for recovering platinum and rhenium from waste reforming catalyst
Through one-step oxidative acid leaching and selective desorption, the problem of complex and high cost of platinum-rhenium recovery process in spent reforming catalysts was solved, and efficient and low-cost platinum-rhenium separation and recovery was achieved, simplifying the process flow and reducing wastewater generation.
Patent Information
- Application Number
- CN202510763292.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-09
- Publication Date
- 2025-10-03
AI Technical Summary
The existing process for recovering platinum-rhenium from spent reforming catalysts is complex, has low separation efficiency, high cost, and generates a large amount of wastewater and waste residue.
A one-step oxidative acid leaching method is used in combination with amino-containing material adsorption and selective desorption to achieve efficient separation and recovery of platinum-rhenium through thiocyanate solution or thiourea solution, simplifying the process flow and reducing reagent consumption and wastewater generation.
It achieves efficient leaching and separation of platinum and rhenium, shortens the process flow, reduces production costs, reduces wastewater generation, and improves the recovery rate of strategic metals and process adaptability.
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Figure CN120738469A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal resource recovery technology, specifically to a method for efficiently recovering the strategic metals platinum and rhenium from spent reforming catalysts. This method enables a short-term separation and recovery of platinum and rhenium, and is suitable for resource recovery of spent reforming catalysts in the petrochemical industry. Background Art
[0002] Platinum (Pt) and rhenium (Re), globally scarce strategic metals, hold an irreplaceable, core position in modern industry. Platinum is the key active component of petroleum reforming catalysts, fulfilling the primary catalytic function. Rhenium, a crucial co-catalyst, significantly enhances the stability and service life of reforming catalysts by inhibiting platinum grain sintering and improving the catalyst's resistance to carbon deposition. Platinum-rhenium catalysts are widely used in the core process of improving gasoline octane rating, enabling efficient conversion in the petrochemical industry.
[0003] However, global platinum-rhenium mineral reserves are extremely uneven and scarce. Platinum resources are primarily concentrated in a few regions, such as South Africa and Russia, while rhenium resources are highly dependent on copper-related ores in countries such as Chile, the United States, and Peru. Extracting platinum-rhenium from raw ores requires complex beneficiation, smelting, and refining processes, resulting in high production costs. At the same time, over 1,000 tons of waste reforming catalysts are generated globally each year due to catalyst deactivation. These waste catalysts contain approximately 0.1%-0.3% platinum and 0.2%-0.5% rhenium, and the platinum-rhenium metals they contain are of enormous value. However, conventional platinum-rhenium recovery processes currently face multiple technical bottlenecks.
[0004] Due to the differences in the chemical activity of platinum and rhenium, many processes often use step-by-step leaching methods to separate platinum and rhenium. For example, sodium salt roasting (such as sodium carbonate, sodium hydroxide, etc.) or potassium salt roasting (such as potassium carbonate, potassium hydroxide, etc.) followed by leaching, or directly using high-concentration alkaline solution to first leach the rhenium; then, the platinum in the leached residue is leached. The recovery process not only needs to operate under high temperature or highly corrosive conditions, but also has high requirements for equipment corrosion resistance, large acid consumption, and large wastewater generation. In addition, there are problems such as the step-by-step leaching process being lengthy and consuming a large amount of reagents.
[0005] Traditional methods for separating platinum and rhenium from leachates rely on solvent extraction (e.g., using amine extractants) or precipitation (e.g., using sodium sulfide for platinum and sodium thiosulfate for rhenium). Solvent extraction requires repeated pH adjustments and the use of large amounts of organic extractants, which can easily lead to emulsification of the extractant and metal carryover. Precipitation, on the other hand, requires multiple dissolution-precipitation cycles, resulting in low overall platinum and rhenium recovery and the generation of large amounts of salt-containing waste residue.
[0006] Therefore, developing a method for recovering platinum-rhenium from spent reforming catalysts with a short process flow, simple method and low cost has important industrial application value. Summary of the Invention
[0007] To address the shortcomings of existing technologies, the present invention provides a method for recovering platinum-rhenium from spent reforming catalysts. This method achieves efficient separation and recovery of platinum-rhenium through a one-step oxidative acidic leaching process, followed by simultaneous adsorption of platinum-rhenium by an amino-containing material, and selective desorption. This method offers advantages such as low reagent and water consumption, a short process flow, and low costs, addressing the technical challenges of complex processes and low separation efficiency in conventional processes.
[0008] The present invention provides a process for efficiently recovering platinum and rhenium from a platinum-rhenium-containing leachate of a spent reforming catalyst, which can be achieved by the following steps:
[0009] (1) Oxidative acid leaching of spent reforming catalyst at 50-300 °C;
[0010] (2) Using amino-containing materials to simultaneously adsorb platinum and rhenium in the leachate;
[0011] (3) Selectively desorbing rhenium with a solution containing thiocyanate to obtain a rhenium-containing desorption solution; or selectively desorbing platinum with a thiourea solution, an acidic thiourea solution, or an alkaline solution to obtain a platinum-containing desorption solution.
[0012] As a preferred technical solution of the present invention, the oxidative acid leaching described in step (1) refers to leaching with HCl in the presence of an oxidant, and the oxidant includes one or more of Cl2, H2O2, HNO3, CuCl2, HClO4, NaClO, and NaClO2.
[0013] As a preferred technical solution of the present invention, the amino group in step (2) is one or more of a primary amine group, a secondary amine group, a tertiary amine group, and a quaternary ammonium group.
[0014] As a preferred technical solution of the present invention, the thiocyanate-containing solution in step (3) is an aqueous solution of thiocyanate, wherein the thiocyanate includes one or more of potassium thiocyanate, sodium thiocyanate, ammonium thiocyanate, and calcium thiocyanate, and the thiocyanate concentration is 0.01 to 3 mol / L.
[0015] As a preferred technical solution of the present invention, the concentration of thiourea in the thiourea solution and the acidic thiourea solution in step (3) is 0.01 to 3 mol / L, the concentration of hydrogen ions is 0 to 2 mol / L, and the alkali solution is one or more of NaOH solution, KOH solution, ammonia solution, LiOH solution, and Ca(OH)2 solution, and the hydroxide concentration is 0.1 to 4 mol / L.
[0016] The beneficial effects that can be achieved by the present invention are:
[0017] This invention achieves efficient leaching of platinum and rhenium through a one-step oxidative acidic leaching process over a wide temperature range (50-300°C), requiring only a single step. The synergistic adsorption of platinum and rhenium by amino-containing materials avoids the tedious step-by-step processing and improves the enrichment efficiency of strategic metals. By utilizing the desorption properties of thiocyanate solution and thiourea solution, acidic thiourea solution, or alkaline solution, platinum and rhenium are sequentially separated, eliminating the need for complex extraction or precipitation steps and significantly shortening the process flow. Compared to traditional processes, this invention reduces reagent and water consumption, and wastewater generation. By simplifying the process and reducing reagent consumption, production costs are reduced, resulting in significant economic and environmental benefits. Depending on actual needs, either rhenium or platinum can be desorbed first. The wide range of desorption solution composition and concentration makes it suitable for waste reforming catalysts of different components, demonstrating strong process adaptability. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 The figure is a schematic diagram of the process of recovering platinum-rhenium from spent reforming catalyst according to the present invention. DETAILED DESCRIPTION
[0019] The present invention will now be further described in detail in conjunction with specific embodiments. The provided embodiments are only used to explain the specific embodiments, operations and efficiency of the present invention, and do not limit the scope of protection of the present invention, and do not limit the present invention in any form.
[0020] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial channels.
[0021] Example 1
[0022] (1) Take 5 g of spent reforming catalyst and place it in a high-temperature resistant reaction vessel. Add 50 mL of a mixed solution consisting of 10% H₂O₂ and 2 mol / L HCl. Perform oxidative acid leaching at a constant temperature of 140°C for 10 hours. Maintain appropriate stirring during the reaction to ensure sufficient solid-liquid contact. After leaching is completed, filter and collect the filtrate to obtain the leachate.
[0023] (2) 100 mg of resin carrying amino groups (primarily primary amine groups) was added to the above-mentioned leachate and placed in an oscillating device at room temperature (30°C) for 24 hours. The adsorption was carried out by filtration to separate the resin and the solution. The adsorption rates of platinum and rhenium were 99.7% and 99.2%, respectively.
[0024] (3) The platinum-rhenium loaded resin was transferred to a desorption vessel, and 25 mL of a 0.2 mol / L aqueous solution of ammonium thiocyanate (NH4SCN) was added. The resin was shaken and desorbed at 250 r / min for 24 hours at room temperature (30°C). After desorption, the resin and the desorption liquid were separated by filtration, and the rhenium-containing desorption liquid was collected. The rhenium desorption rate was 99.0%, and only platinum ions remained on the resin.
[0025] (4) Transfer the platinum-loaded resin separated in step (3) to a new desorption vessel and add 25 mL of acidic thiourea desorption solution (prepared from hydrochloric acid and thiourea, with a hydrogen ion concentration of 0.1 mol / L and a thiourea concentration of 0.05 mol / L). Desorb the resin at room temperature (30°C) at a speed of 250 r / min for 24 hours. After desorption, filter and separate the resin and the desorption solution, collect the platinum-containing desorption solution, and measure the platinum desorption rate to be 99.1%. The resin after two desorptions can be reused after washing and regeneration.
[0026] Example 2
[0027] (1) Take 10 g of spent reforming catalyst and place it in a high-temperature resistant reaction vessel. Add 100 mL of a mixed solution consisting of 10% HClO4 and 3 mol / L HCl. Perform oxidative acid leaching at a constant temperature of 160 °C for 8 hours. Maintain appropriate stirring during the reaction to ensure sufficient solid-liquid contact. After leaching is completed, filter and collect the filtrate to obtain the leachate.
[0028] (2) 200 mg of a resin carrying amino groups (primarily tertiary amine groups) was added to the above-mentioned leachate and placed in an oscillating device at room temperature (20°C) for 24 hours. The adsorption was carried out by filtering the resin and the solution. The adsorption rates for platinum and rhenium were 99.8% and 99.7%, respectively.
[0029] (3) The platinum-rhenium loaded resin was transferred to a desorption vessel, and 50 mL of acidic thiourea desorption solution (prepared from hydrochloric acid and thiourea, with a hydrogen ion concentration of 0.3 mol / L and a thiourea concentration of 0.1 mol / L) was added. The resin was shaken and desorbed at 200 r / min for 24 hours at room temperature (20°C). After desorption, the resin and the desorption solution were separated by filtration, and the platinum-containing desorption solution was collected. The platinum desorption rate was measured to be 99.7%, and only rhenium ions remained on the resin.
[0030] (4) The rhenium-loaded resin separated in step (3) was transferred to a new desorption vessel, 50 mL of 0.3 mol / L ammonium thiocyanate (NH4SCN) solution was added, and desorption was carried out at 200 r / min at room temperature (20°C) for 24 hours. After desorption, the resin and the desorption liquid were separated by filtration, and the rhenium-containing desorption liquid was collected. The rhenium desorption rate was measured to be 99.5%. The resin after two desorptions can be reused after washing and regeneration.
[0031] Example 3
[0032] (1) Take 100 g of spent reforming catalyst and place it in a high-temperature resistant reaction vessel. Add 400 mL of a mixed solution consisting of 100 mL of concentrated HNO3 and 300 mL of concentrated HCl. Perform oxidative acid leaching at a constant temperature of 100 °C for 12 hours. Maintain appropriate stirring during the reaction to ensure sufficient solid-liquid contact. After leaching is completed, filter and collect the filtrate to obtain the leachate.
[0033] (2) Take 2000 mg of resin carrying amino groups (mainly secondary amine groups) as the adsorption material and load it into the adsorption column. The above-mentioned leachate is passed through the adsorption column at a flow rate of 1 mL / min for adsorption. After the adsorption is completed, the adsorption rate of platinum is measured to be 99.9%, and the adsorption rate of rhenium is 99.9%.
[0034] (3) 500 mL of a 0.5 mol / L aqueous solution of ammonium thiocyanate (NH4SCN) was passed through the adsorption column at a flow rate of 1 mL / min for desorption. After desorption, the rhenium-containing desorbent was collected. The rhenium desorption rate was measured to be 99.9%, with only platinum ions remaining on the resin.
[0035] (4) 500 mL of 1 mol / L sodium hydroxide (NaOH) solution (0.5 mol / L thiourea) was passed through the adsorption column at a flow rate of 1 mL / min for desorption. After desorption, the platinum-containing desorption liquid was collected, and the platinum desorption rate was measured to be 99.9%. The resin after two desorptions can be washed and regenerated for reuse.
[0036] Example 4
[0037] (1) 200 g of spent reforming catalyst was placed in a high-temperature resistant reaction vessel and 600 mL of a mixed solution consisting of 8% NaClO2 and 3 mol / L HCl was added. Oxidative acid leaching was performed at a constant temperature of 120 °C for 14 hours. During the reaction, appropriate stirring was maintained to ensure sufficient solid-liquid contact. After leaching was completed, the filtrate was filtered and collected to obtain the leachate.
[0038] (2) Take 5000 mg of resin carrying amino groups (mainly tertiary amine groups) as the adsorption material and load it into the adsorption column. The above-mentioned leachate is passed through the adsorption column at a flow rate of 2 mL / min for adsorption. After the adsorption is completed, the adsorption rate of platinum is measured to be 99.9%, and the adsorption rate of rhenium is 99.9%.
[0039] (3) 400 mL of acidic thiourea desorption solution (prepared from hydrochloric acid and thiourea, with a hydrogen ion concentration of 0.5 mol / L and a thiourea concentration of 0.3 mol / L) was passed through the adsorption column at a flow rate of 1 mL / min for desorption. After desorption, the platinum-containing desorption solution was collected, and the platinum desorption rate was measured to be 99.8%, with only rhenium ions remaining on the resin.
[0040] (4) 400 mL of a 0.5 mol / L potassium thiocyanate (KSCN) aqueous solution was passed through the adsorption column at a flow rate of 1 mL / min for desorption. After desorption, the rhenium-containing desorbent was collected, and the rhenium desorption rate was measured to be 99.7%. The resin after two desorptions can be washed and regenerated for reuse.
[0041] The present invention has been described in detail above, and the embodiments of the present invention are merely illustrative and not intended to limit the present invention. Any modifications, uses, or improvements based on the underlying principles of the present invention are intended to be within the scope of this application, including reasonable modifications made using conventional techniques in the art. Therefore, the present invention should be considered to encompass the broadest scope consistent with its disclosed principles and innovative features, and not be limited to the specific embodiments described.
Claims
1. A method for recovering platinum-rhenium from spent reforming catalysts, characterized in that: The active components of the spent reforming catalyst include platinum and rhenium, and the recovery steps include: (1) Oxidative acid leaching of spent reforming catalyst at 50-300 °C; (2) Using amino-containing materials to simultaneously adsorb platinum and rhenium in the leachate; (3) Selectively desorbing rhenium with a solution containing thiocyanate to obtain a rhenium-containing desorption solution; or selectively desorbing platinum with thiourea, acidic thiourea or alkaline solution to obtain a platinum-containing desorption solution.
2. The method for recovering platinum-rhenium from spent reforming catalyst according to claim 1, wherein: The oxidative acid leaching described in step (1) refers to leaching with HCl in the presence of an oxidant, and the oxidant includes one or more of Cl2, H2O2, HNO3, CuCl2, HClO4, NaClO, and NaClO2.
3. The method for recovering platinum-rhenium from spent reforming catalyst according to claim 1, wherein: The amino group in step (2) is one or more of a primary amine group, a secondary amine group, a tertiary amine group, and a quaternary ammonium group.
4. The method for recovering platinum-rhenium from spent reforming catalyst according to claim 1, wherein: The thiocyanate-containing solution in step (3) is an aqueous solution of thiocyanate, wherein the thiocyanate includes one or more of potassium thiocyanate, sodium thiocyanate, ammonium thiocyanate, and calcium thiocyanate, and the thiocyanate concentration is 0.01 to 3 mol / L.
5. The method for recovering platinum-rhenium from spent reforming catalyst according to claim 1, wherein: The concentration of thiourea in the thiourea solution and the acidic thiourea solution in step (3) is 0.01 to 3 mol / L, the concentration of hydrogen ions is 0 to 2 mol / L, the alkali solution is one or more of NaOH solution, KOH solution, ammonia solution, LiOH solution, and Ca(OH)2 solution, and the hydroxide concentration is 0.1 to 4 mol / L.