Method for deeply recovering rhodium and iridium from waste adsorbent

Abstract

The invention discloses a method for deeply recovering rhodium and iridium from a waste adsorbent, which comprises the following steps: S1, pressurized desorption: mixing the waste adsorbent containing rhodium and iridium with a desorption agent according to a mass ratio of 1: 1, putting the mixture into a pressurizing device, heating to 360-520 DEG C, introducing oxygen until the pressure is 1.1-1.3 Mpa, and maintaining the pressure for 60-90 minutes to destroy the matrix components of the adsorbent so as to realize deep desorption of rhodium and iridium; s2, leaching and desilicication are conducted, specifically, the pressurized material in the step S1 is pulpified by adopting a leaching agent according to the solid-to-liquid ratio of 1: (3-5), then the temperature is increased to 50-60 DEG C, leaching is conducted for 30-50 min, solid-liquid separation is conducted after leaching is completed, and a leached material is obtained; and S3, dissolution and impurity removal are conducted, specifically, the leaching material obtained in the step S2 is subjected to hydrochloric acid leaching, the acidity is controlled to be 2-3 mol / L, the reaction temperature is 70-75 DEG C, the reaction time is 30 min, filtration is conducted after dissolution, and an insoluble material containing rhodium and iridium is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy of precious metals, and particularly relates to a method for deeply recovering rhodium and iridium from waste adsorbents. Background Art

[0002] Rhodium and iridium metals are known as the "vitamins" and "high-tech metals" of modern industry. Their unique financial attributes, irreplaceable functional attributes, and scarcity determine that the growth potential of platinum group metals is huge. There is a large market demand in aspects such as petroleum industry catalysts, automotive three-way tail gas purifiers, catalytic hydrogenation, methanol carbonylation, and hydroformylation of olefins.

[0003] Currently, some domestic precious metal production lines use functionalized adsorbents to enrich rhodium and iridium. The loaded adsorbents are pretreated - desorbed - copper-nickel separated - platinum-palladium separated - rhodium-iridium refined to obtain qualified rhodium-iridium products. After the rhodium-iridium adsorbent is desorbed, there is still about 0.2 - 0.4% of rhodium and iridium remaining. The binding force between this part of rhodium and iridium and the functional groups in the adsorbent is strong, and it is difficult to completely desorb it by ordinary aqua regia or chlorination treatment. There is no corresponding treatment process. To improve the efficient utilization of limited resources, new treatment processes need to be developed to achieve the deep recovery of rhodium and iridium from waste adsorbents. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a method for deeply recovering rhodium and iridium from waste adsorbents.

[0005] To achieve the above object, the technical solution of the present invention is as follows: A method for deeply recovering rhodium and iridium from waste adsorbents, comprising the following steps: S1. Pressurized desorption: Mix the waste adsorbent containing rhodium and iridium with a desorbent at a mass ratio of 1:1, put it into a pressurizing device, heat up to 360 - 520 °C, introduce oxygen until the pressure reaches 1.1 - 1.3 Mpa, and then keep the pressure for 60 - 90 min to destroy the matrix components of the adsorbent and achieve deep desorption of rhodium and iridium; S2. Leaching and desilication: Pulverize the pressurized material in step S1 with a leaching agent at a solid-liquid ratio of 1:3 - 5, heat up to 50 - 60 °C, leach for 30 - 50 min, and perform solid-liquid separation after leaching to obtain the leached material; S3. Dissolution and impurity removal: Perform hydrochloric acid leaching on the leached material obtained in step S2, control the acidity at 2 - 3 mol / L, the reaction temperature at 70 - 75 °C, and the reaction time at 30 min. After dissolution, filter to obtain the insoluble material containing rhodium and iridium; S4. Microwave activation: Mix the insoluble material obtained in step S3 with ammonium chlorate in a mass ratio of 1:1.5 - 3, then place the mixture in a microwave reduction furnace. Introduce nitrogen gas to heat up to 500 - 600 °C and react for 1 - 3 hours. After the activation is completed, introduce nitrogen gas to cool down to room temperature to obtain a soluble rhodium and iridium enriched material, and produce qualified rhodium and iridium products.

[0006] Among them, in the said step S1, the desorbent is a mixed reagent of hydrogen peroxide and ammonium carbonate.

[0007] Among them, the preparation process of the desorbent is: Add ammonium carbonate powder into a special container, and then add hydrogen peroxide with a mass fraction of 5% of ammonium carbonate and stir evenly to obtain the mixed reagent.

[0008] Among them, in the said step S2, the leaching agent is a 35% ethanol solution.

[0009] The beneficial effects of the present invention are as follows: 1. In step one of the present invention: pressure desorption, a mixed reagent of ammonium carbonate containing 5% hydrogen peroxide is used to destroy the silica matrix of the waste adsorbent under pressure, so that the silicon dioxide therein reacts with ammonium carbonate to form ammonium silicate, realizing the soluble transformation of the silica matrix; and the purpose of adding hydrogen peroxide is for the oxidation protection of desorbing rhodium and iridium metals, avoiding the loss of rhodium and iridium during the silicon-based leaching and impurity removal processes.

[0010] 2. In step two of the present invention: leaching and desilication, a 35% ethanol solution is used to leach the pressurized material. Utilizing the characteristics that ammonium silicate is easily soluble in alcohol and water, while rhodium and iridium metal oxides are difficult to dissolve, the ammonium silicate therein is completely dissolved, realizing the complete separation of the silica matrix and rhodium and iridium metals.

[0011] 3. In step three of the present invention: dissolution and impurity removal, a 2 - 3 mol / L hydrochloric acid solution is used to leach and remove the base metals such as nickel, iron, zinc, and copper in the leached material, realizing the purification and enrichment of rhodium and iridium materials.

[0012] 4. In step four of the present invention: microwave activation, ammonium chlorate is used to activate the insoluble material containing rhodium and iridium. Through the action of microwave, the energy dissipation inside the material is converted into the kinetic energy and potential energy of internal molecules, making each molecule and atom become a heat source, thereby realizing rapid and uniform heating, converting rhodium in the material into rhodium(III) and iridium into iridium(IV), and finally generating solid sodium rhodium chloride and sodium iridium chloride; and introducing nitrogen gas during the activation process is to protect the stable progress of the activation reaction and prevent the activation reaction from being too violent due to the entry of oxygen, resulting in safety risks. Brief Description of the Drawings

[0013] Figure 1 is the process flow chart of the present invention. Detailed Embodiments

[0014] To make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0015] Example 1 As Figure 1 shown, a method for deeply recovering rhodium and iridium from waste adsorbents includes the following steps: S1. Pressurized desorption: Mix the waste adsorbent containing rhodium and iridium with the desorbent at a mass ratio of 1:1, then put them into a pressurizing device, heat up to 360°C, introduce oxygen until the pressure reaches 1.1 Mpa, and then keep the pressure for 60 minutes to destroy the matrix components of the adsorbent and achieve deep desorption of rhodium and iridium; S2. Leaching and desilication: Pulverize the pressurized material in step S1 with a leaching agent at a solid-liquid ratio of 1:3, then heat up to 50°C and leach for 30 minutes. After the leaching is completed, perform solid-liquid separation to obtain the leached material; S3. Dissolution and impurity removal: Perform hydrochloric acid leaching on the leached material obtained in step S2, control the acidity at 2 mol / L, the reaction temperature at 70°C, and the reaction time at 30 minutes. After dissolution, filter to obtain the insoluble material containing rhodium and iridium; S4. Microwave activation: Mix the insoluble material in step S3 with ammonium chlorate at a mass ratio of 1:1.5, then place them in a microwave reduction furnace, introduce nitrogen, heat up to 500°C, and react for 1 hour. After the activation is completed, introduce nitrogen to cool to room temperature to obtain a soluble rhodium and iridium enrichment material and produce qualified rhodium and iridium products.

[0016] Among them, in step S1, the desorbent is a mixed reagent of hydrogen peroxide and ammonium carbonate.

[0017] Among them, the preparation process of the desorbent is: Add ammonium carbonate powder into a special container, and then add hydrogen peroxide with a mass fraction of 5% of ammonium carbonate and stir evenly to obtain the mixed reagent.

[0018] Among them, in step S2, the leaching agent is a 35% ethanol solution.

[0019] Example 2 As Figure 1 shown, a method for deeply recovering rhodium and iridium from waste adsorbents includes the following steps: S1. Pressurized desorption: Mix the waste adsorbent containing rhodium and iridium with the desorbent at a mass ratio of 1:1, then put them into a pressurizing device, heat up to 520°C, introduce oxygen until the pressure reaches 1.3 Mpa, and then keep the pressure for 90 minutes to destroy the matrix components of the adsorbent and achieve deep desorption of rhodium and iridium; S2. Leaching and desilication: The pressurized material in step S1 is slurried with a leaching agent at a solid-liquid ratio of 1:5, then heated to 60°C and leached for 50 minutes. After the leaching is completed, solid-liquid separation is carried out to obtain the leached material. S3. Dissolution and impurity removal: The leached material obtained in step S2 is subjected to hydrochloric acid leaching, controlling the acidity at 3 mol / L, the reaction temperature at 75°C, and the reaction time at 30 minutes. After dissolution, filtration is carried out to obtain the insoluble material containing rhodium and iridium. S4. Microwave activation: The insoluble material in step S3 is mixed with ammonium chlorate in a mass ratio of 1:3, then placed in a microwave reduction furnace, nitrogen is introduced, heated to 600°C and reacted for 3 hours. After the activation is completed, nitrogen is introduced to cool to room temperature to obtain the soluble rhodium and iridium enriched material, and qualified rhodium and iridium products are produced.

[0020] Among them, in step S1, the desorbent is a mixed reagent of hydrogen peroxide and ammonium carbonate.

[0021] Among them, the preparation process of the desorbent is: adding ammonium carbonate powder in a special container, and then adding hydrogen peroxide with a mass fraction of 5% of ammonium carbonate and stirring evenly to obtain the mixed reagent.

[0022] Among them, in step S2, the leaching agent is a 35% ethanol solution.

[0023] Example 3 As Figure 1 shown, a method for deeply recovering rhodium and iridium from waste adsorbents includes the following steps: Step 1: Mix 5 mL of hydrogen peroxide and 100 g of ammonium carbonate, then add 100 g of waste adsorbent and stir evenly, put it into a pressurizing device, heat to 380°C, introduce oxygen until the pressure reaches 1.1 Mpa, and keep the pressure for 60 minutes to obtain 187 g of pressurized material. Step 2: Take 196 mL of anhydrous ethanol, add 365 mL and stir evenly to obtain 561 mL of ethanol solution with a volume fraction of 35%. Use this ethanol solution to slurry the pressurized material obtained in step 1, then heat to 60°C and leach for 50 minutes. After the leaching is completed, solid-liquid separation is carried out to obtain 53 g of leached material. Step 3: Prepare a hydrochloric acid solution with an acidity of 2 mol / L to leach the leached material in step 2, control the reaction temperature at 75°C, and the reaction time at 30 minutes. After dissolution, filtration is carried out to obtain 38 g of insoluble material containing rhodium and iridium.

[0024] Step 4: Take 76 g of ammonium chlorate and mix it with the rhodium and iridium insoluble material in step 3, then place it in a microwave reduction furnace, introduce nitrogen, heat to 500°C and react for 1.5 hours. After the activation is completed, introduce nitrogen to cool to room temperature to obtain 51 g of soluble rhodium and iridium enriched material.

[0025] Using the above method, the metal content of the rhodium and iridium enriched material after being dissolved with 6 mol / L hydrochloric acid is shown in Table 1: The dissolution solution of the above rhodium-iridium enriched material produces qualified rhodium-iridium products after connecting to the existing separation and refining process.

[0026] It should be understood that the above specific embodiments of the present invention are only for illustrative explanation or interpretation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A method for deeply recovering rhodium and iridium from waste adsorbents, characterized in that, It includes the following steps: S1. Pressurized desorption: Mix the rhodium-iridium-containing waste adsorbent and the desorbent at a mass ratio of 1:1, put them into a pressurizing device, heat up to 360 - 520 °C, introduce oxygen until the pressure reaches 1.1 - 1.3 Mpa, and then keep the pressure for 60 - 90 min to destroy the matrix components of the adsorbent and achieve deep desorption of rhodium and iridium; S2. Leaching for desilication: Pulverize the pressurized material in step S1 with a leaching agent at a solid-liquid ratio of 1:3 - 5, heat up to 50 - 60 °C and leach for 30 - 50 min. After the leaching is completed, perform solid-liquid separation to obtain the leached material; S3. Dissolution for impurity removal: Perform hydrochloric acid leaching on the leached material obtained in step S2, control the acidity at 2 - 3 mol / L, the reaction temperature at 70 - 75 °C, and the reaction time at 30 min. After dissolution, filter to obtain the insoluble material containing rhodium and iridium; S4. Microwave activation: Mix the insoluble material in step S3 with ammonium chlorate at a mass ratio of 1:1.5 - 3, place it in a microwave reduction furnace, introduce nitrogen, heat up to 500 - 600 °C and react for 1 - 3 h. After the activation is completed, introduce nitrogen to cool to room temperature to obtain a soluble rhodium-iridium enriched material and produce qualified rhodium-iridium products.

2. A method for deeply recovering rhodium and iridium from waste adsorbents according to claim 1, characterized in that: In step S1, the desorbent is a mixed reagent of hydrogen peroxide and ammonium carbonate.

3. A method for deeply recovering rhodium and iridium from waste adsorbents according to claim 2, characterized in that: The preparation process of the desorbent is: Add ammonium carbonate powder into a special container, and then add hydrogen peroxide with a mass fraction of 5% of ammonium carbonate and stir evenly to obtain the mixed reagent.

4. A method for deeply recovering rhodium and iridium from waste adsorbents according to claim 1, characterized in that: In step S2, the leaching agent is a 35% ethanol solution.

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