Method for enriching platinum group metals from iron-captured platinum group metals
By using the secondary resources containing copper as the control metal in Fe-PGMs alloys, the low-temperature oxidation reaction and ultrasonic vibration magnetic separation methods are solved, and the problems of high energy consumption and long process in the prior art are achieved, and the efficient enrichment and energy consumption reduction of platinum group metals are achieved.
Patent Information
- Application Number
- CN202510453424.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2025-05-30
AI Technical Summary
The method of separating platinum group metals from Fe-PGMs alloys in the prior art has problems such as high energy consumption, long process and complex operation, and it is difficult to realize a low energy consumption and short process enrichment process.
By placing the control metal (oxygenophilicity is less than iron and greater than platinum group metal, such as secondary resources containing copper) around iron, heat up and perform an oxidation reaction, the iron is oxidized to magnetic iron oxides, and the enriched platinum group metal is obtained after the iron oxide is removed. This method performs an oxidation reaction at a low temperature of 350-450°C, and uses ultrasonic vibration and magnetic separation to achieve separation of iron and platinum group metal.
The efficient enrichment of platinum group metals is achieved. The content of platinum group metals is 6 to 7 times higher than that of iron-captured platinum group metals, and the energy consumption is reduced, the process is simplified, and the operation is relatively simple.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of platinum group metal metallurgy, and particularly relates to a method for enriching platinum group metals from iron-captured platinum group metals. Background Art
[0002] Platinum Group Metals (PGMs) have the characteristics of high melting point, corrosion resistance, good catalytic activity, etc., and are widely used in catalysis, national defense and military industries, etc., and belong to strategic metals. The proven PGMs mineral resources in China are extremely scarce and have low grades, but the demand is huge, and the contradiction between supply and demand is sharp. Recycling PGMs from secondary resources such as waste automotive catalysts has become an important way for their sustainable development. Among them, the Fe-PGMs alloy is the product of iron-capturing PGMs secondary resources. The Si element in the alloy will make the captured product dense, which is difficult to crush and separate, and hinders chemical dissolution.
[0003] At present, the methods for separating PGMs from Fe-PGMs alloys mainly include acid leaching method, electrolysis method and oxidation separation method. The acid leaching method realizes the deep enrichment of platinum group metals by using a combined process of sulfuric acid dissolution, sodium hydroxide roasting, water leaching, and dilute sulfuric acid dissolution. This method has a long recovery process, and platinum group metals stay in each stage. The electrolysis method uses an iron alloy as the anode and an inert material as the cathode. By controlling the voltage, platinum anode mud and palladium and rhodium solutions can be obtained, and then palladium and rhodium are extracted using an extractant. However, due to the large amount of iron present, this method has disadvantages such as high power consumption and expensive extractant. The existing oxidation separation method in the prior art separates PGMs from iron by adding CaO, SiO 2 and Al 2 O 3 , and passing oxygen or air at a temperature of 1500 °C to oxidize iron into the slag phase to achieve the separation of PGMs and iron. This method has complex operations and high energy consumption. Therefore, it is necessary to develop a Fe-PGMs alloy separation and enrichment process with low energy consumption and short process. Summary of the Invention
[0004] In view of this, the purpose of the present invention is to provide a method for enriching platinum group metals from iron-captured platinum group metals. The method provided by the present invention has low energy consumption, short process and good enrichment effect.
[0005] To solve the above technical problems, the present invention provides the following technical solutions:
[0006] The present invention provides a method for enriching platinum group metals from iron-captured platinum group metals, comprising the following steps:
[0007] Place the control metal around the iron for trapping platinum group metals, heat up for an oxidation reaction, the iron in the iron for trapping platinum group metals is oxidized to magnetic iron oxide, after removing the iron oxide, enriched platinum group metals are obtained; the oxygen affinity of the control metal is less than that of iron and greater than that of platinum group metals;
[0008] The temperature of the oxidation reaction is 350 - 450 °C.
[0009] Preferably, the control metal is a copper-containing secondary resource; the copper content in the copper-containing secondary resource is 80 - 90 wt%.
[0010] Preferably, the mass ratio of the control metal to the iron for trapping platinum group metals ≥ 1:1.
[0011] Preferably, the oxidation reaction is carried out under a blast condition, and the wind speed is 1000 - 1500 r / min.
[0012] Preferably, the time of the oxidation reaction is 3 - 5 h.
[0013] Preferably, the removal of the iron oxide includes: subjecting the material after the oxidation reaction of the iron for trapping platinum group metals to ultrasonic vibration screening and magnetic separation.
[0014] Preferably, the frequency of the ultrasonic vibration screening is 15 - 20 kHz.
[0015] Preferably, the ultrasonic vibration screening includes performing the first screening, the second screening, and the third screening in sequence;
[0016] The screening mesh number of the first screening is 15 - 25 meshes;
[0017] The screening mesh number of the second screening is 30 - 50 meshes;
[0018] The screening mesh number of the third screening is 90 - 120 meshes.
[0019] Preferably, the time of the first screening, the second screening, and the third screening is independently 20 - 50 min.
[0020] Preferably, the composition of the iron for trapping platinum group metals includes 80 - 83 wt% Fe, 8 - 12 wt% Si, 0.3 - 0.8 wt% Pt, 2.5 - 3.5 wt% Pd, 0.7 - 1.2 wt% Rh.
[0021] The present invention provides a method for enriching platinum group metals from iron-captured platinum group metals, comprising the following steps: placing a control metal around the iron-captured platinum group metals, heating up for an oxidation reaction, oxidizing the iron in the iron-captured platinum group metals into magnetic iron oxide, and obtaining the enriched platinum group metals after removing the iron oxide; the oxygen affinity of the control metal is less than that of iron and greater than that of the platinum group metals; the temperature of the oxidation reaction is 350-450 °C. At the same temperature, Fe is oxidized first, and the platinum group metals (Pt, Pd, Rh) are oxidized later. The present invention utilizes this rule. By adding a control metal with an oxygen affinity less than that of iron and greater than that of the platinum group metals, the iron in the iron-captured platinum group metals is converted into magnetic oxide at a low temperature of 350-450 °C, while the platinum group metals are not converted, thereby realizing the separation of iron from the platinum group metals and the enrichment of the platinum group metals.
[0022] Furthermore, the present invention utilizes ultrasonic vibration and magnetic separation to achieve the separation of iron and pore formation of the product, improving the surface area and rate of subsequent dissolution, reducing the dissolution time, reducing energy consumption and the generation of waste liquid, reducing the operation process, lowering energy consumption, and saving costs.
[0023] Furthermore, the control metal selected from secondary resources containing copper can be oxidized to realize waste utilization and obtain secondary products, which is beneficial to acid leaching and recovery. From the data of the examples, it can be seen that the platinum group content in the platinum group metal-containing material obtained by using the method provided by the present invention is increased by 6-7 times compared with that of the iron-captured platinum group metals. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0025] Figure 1 It is an oxygen potential diagram of Pt, Pd, Rh, Cu, Fe, and Si;
[0026] Figure 2 It is a schematic structural diagram of the control oxidation device provided by the present invention;
[0027] Among them, 1 - gas outlet, 2 - gas inlet, 3 - control metal, 4 - stainless steel reaction furnace, 5 - stainless steel reaction platform, 6 - Fe-PGMs, 7 - residue collection port, 8 - air holes, 9 - heating device, 10 - blower, 11 - cooling water device. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0028] The present invention provides a method for enriching platinum group metals from iron-captured platinum group metals, comprising the following steps:
[0029] Place the control metal around the iron for trapping platinum group metals, heat it up for oxidation reaction. The iron in the iron for trapping platinum group metals is oxidized to magnetic iron oxide. After removing the iron oxide, enriched platinum group metals are obtained. The oxygen affinity of the control metal is less than that of iron and greater than that of platinum group metals.
[0030] The temperature of the oxidation reaction is 350 - 450 °C.
[0031] In the present invention, unless otherwise specified, the raw materials and equipment used are well-known commercially available products in the art.
[0032] In the present invention, the control metal is preferably a copper-containing secondary resource. The copper-containing secondary resource preferably includes one or more of copper wire, copper gate, and copper slag. In the present invention, the copper content in the copper-containing secondary resource is preferably 80 - 90 wt%. In the present invention, when the copper-containing secondary resource is copper wire, the length of the copper wire is preferably 1 - 2 cm. In specific embodiments, the length of the copper wire can be 1 cm, 1.2 cm, 1.5 cm, 1.7 cm, or 2 cm. When the copper-containing secondary resource is copper gate and / or copper slag, the particle size of the copper-containing secondary resource is preferably 1 - 5 cm.
[0033] In the present invention, the composition of the iron for trapping platinum group metals preferably includes 80 - 83 wt% Fe, 8 - 12 wt% Si, 0.3 - 0.8 wt% Pt, 2.5 - 3.5 wt% Pd, 0.7 - 1.2 wt% Rh. The particle size of the iron for trapping platinum group metals is preferably 0.5 - 1 cm. In specific embodiments, the particle size of the iron for trapping platinum group metals can be 0.5 cm, 0.8 cm, or 1 cm.
[0034] In the present invention, the mass ratio of the control metal to the iron for trapping platinum group metals is preferably ≥1:1, more preferably (1 - 2):1. The greater the amount of the control metal used, the higher the content of the finally enriched platinum group metals. In specific embodiments, the mass ratio of the control metal to the iron for trapping platinum group metals can be 1:1, 1.2:1, 1.5:1, 1.8:1, or 2:1. In the present invention, it is preferred to use a copper-containing secondary resource as the control metal. By controlling the dosage ratio of the copper-containing secondary resource to the iron for trapping platinum group metals at (1 - 2):1, not only can the enrichment effect of platinum group metals be ensured, but also the copper in the copper-containing secondary resource can be converted into copper oxide to obtain a secondary product, which is beneficial to the recycling of copper in the copper-containing secondary resource.
[0035] In the present invention, placing the control metal around the iron for trapping platinum group metals can ensure that the oxidation behavior can be controlled in all directions, maximize the retention of platinum group metals, and avoid the reduction of the content of platinum group metals caused by the oxidation of platinum group metals.
[0036] In the present invention, the temperature of the oxidation reaction is preferably 350 to 450 °C. In specific embodiments, the temperature of the oxidation reaction can be 350 °C, 380 °C, 400 °C, 420 °C or 450 °C; the time is preferably 3 to 5 h. In specific embodiments, the time of the oxidation reaction can be 3 h, 4 h or 5 h.
[0037] In the present invention, the oxidation reaction is preferably carried out under blast conditions, and the wind speed is preferably 1000 to 1500 r / min. In specific embodiments, the wind speed during the oxidation reaction can be 1000 r / min, 1200 r / min or 1500 r / min. Ventilation can enhance the effect of internal air flow and strengthen the degree of oxidation reaction. During the oxidation reaction, the iron in the iron-captured platinum group metals reacts preferentially with oxygen to form magnetic and loose iron oxides. Then, oxygen will react with the controlled metals, avoiding the reaction of the platinum group elements in the iron-captured platinum group metals with oxygen. After the experiment, iron oxides are obtained to wrap the platinum group metal-containing materials, which is beneficial to the subsequent vibration magnetic separation to realize the separation of iron oxides and platinum group metals.
[0038] In the present invention, the removal of iron oxides preferably includes: ultrasonic vibration screening and magnetic separation of the materials after the oxidation reaction of the iron-captured platinum group metals. In the present invention, the frequency of the ultrasonic vibration screening is preferably 15 to 20 kHz. In specific embodiments, the frequency of the ultrasonic vibration screening can be 15 kHz, 18 kHz or 20 kHz. After oxidation, the raw materials become loose, but there is a part that is not oxidized. The loose part is removed by ultrasonic vibration to realize the separation of iron oxides and enriched platinum group metals.
[0039] In the present invention, the ultrasonic vibration screening preferably includes first screening, second screening, and third screening in sequence; the screening mesh number of the first screening is preferably 15 - 25 meshes. In a specific embodiment, the screening mesh number of the first screening can be 15 meshes, 20 meshes, or 25 meshes, and the time of the first screening is preferably 20 - 50 min. In a specific embodiment, the time of the first screening can be 20 min, 30 min, 40 min, or 50 min; the screening mesh number of the second screening is preferably 30 - 50 meshes. In a specific embodiment, the screening mesh number of the second screening can be 30 meshes, 40 meshes, or 50 meshes, and the time of the second screening is preferably 20 - 50 min. In a specific embodiment, the time of the second screening can be 20 min, 30 min, 40 min, or 50 min; the screening mesh number of the third screening is preferably 90 - 120 meshes. In a specific embodiment, the screening mesh number of the third screening can be 90 meshes, 100 meshes, or 120 meshes, and the time of the third screening is preferably 20 - 50 min. In a specific embodiment, the time of the third screening can be 20 min, 30 min, 40 min, or 50 min.
[0040] The present invention has no special requirements for the method of magnetic separation, and well-known technical means in the art can be adopted. Through magnetic separation, ferromagnetic oxides and platinum group metal-containing materials are separated.
[0041] Figure 1 It is the oxygen potential diagram of Pt, Pd, Rh, Cu, Fe, and Si. By analyzing the oxygen potential diagram, it can be known that the smaller ΔG (the lower the position), the easier it is to react with oxygen to form the corresponding oxide. At the same temperature, the order of ΔG from large to small is Pt, Pd, Rh > Cu > Fe > Si, indicating that at the same temperature, Si, Fe, and Cu are oxidized first, and Pt, Pd, and Rh are oxidized later. Therefore, during the metal oxidation process, copper with an oxygen affinity less than that of iron and greater than that of platinum group metals is selected, and by controlling the oxidation temperature, the iron in the Fe - PGMs alloy can be well converted into oxides, while the platinum group metals are not converted, forming a loose product. Finally, the iron oxides and platinum group metals are separated by ultrasonic vibration and magnetic separation. At the same time, in order to meet the requirements of a green and environmentally friendly method, the selected material is copper-containing waste.
[0042] In the present invention, the oxidation reaction is preferably carried out in a device for controlled oxidation, such as Figure 2As shown, the device for controlled oxidation preferably includes an air outlet 1, an air inlet 2, a stainless-steel reaction furnace 4, a stainless-steel reaction platform 5, a residue collection port 7, air holes 8, a heating device 9, a blower 10, and a cooling water device 11; the heating device 9 wraps around the stainless-steel reaction furnace 4, the cooling water device 11 is located at the top of the stainless-steel reaction furnace 4, the stainless-steel reaction platform 5 is located at the center of the stainless-steel reaction furnace 4, the stainless-steel reaction platform 5 is provided with n air holes 8, the air inlet 2 is located between the residue collection port 7 and the stainless-steel reaction platform 5, and is respectively arranged on both sides of the stainless-steel reaction furnace 4. The blower 10 is connected to any one of the air inlets 2, the air outlet 1 is located at the top of the stainless-steel reaction furnace 4, and the residue collection port 7 is located at the bottom of the stainless-steel reaction furnace 4. In the present invention, a blower 10 is provided below the stainless-steel reaction platform 5, and air holes 8 are provided on the stainless-steel reaction platform 5, which can strengthen air flow and enhance the degree of oxidation reaction.
[0043] In the present invention, the steps of enriching platinum group metals from iron-captured platinum group metals using the device for controlled oxidation preferably include: checking the equipment, installing the residue collection port 7, placing the control metal 3 around the Fe-PGMs 6 in the stainless-steel reaction platform 5, turning on the blower 10, two air inlets 2, and the heating device 9 to carry out the oxidation reaction. After the reaction is completed, turn off the heating device 9, turn on the cooling water device 11, cool down to room temperature, then turn off the blower 10, collect the oxidized product into the corresponding residue collection port 7, and clean the device.
[0044] In the present invention, before placing the control metal 3 around the Fe-PGMs 6 in the stainless-steel reaction platform 5, it is preferably further included to grind the Fe-PGMs and grind or shear the control metal.
[0045] The present invention has no special requirements for the method of grinding, and common technical means in the art can be adopted.
[0046] The present invention has no special requirements for the method of shearing, and common technical means in the art can be adopted.
[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Any modifications, equivalent replacements, improvements, etc. made to the embodiments of the present invention without creative labor based on the technical essence and general principles of the present invention shall fall within the protection scope of the present invention.
[0048] Table 1 Main components of the raw material iron-captured platinum group metals
[0049] Component Fe Si Pt Pd Rh Content (wt%) 82.5 10.3 0.6 3.1 0.8
[0050] The secondary resource of raw copper is copper wire, with the main component being copper and a content of 85 wt%.
[0051] Example 1
[0052] Check the equipment, install the residue collection port, grind 20 g of iron for trapping platinum group metals, cut 30 g of the secondary resource of copper into pieces 1 - 1.5 cm in length, place the secondary resource of copper around the iron for trapping platinum group metals on the reaction platform, turn on the blower, adjust the wind speed to 1200 r / min, oxidize at 400 °C for 3 h. After the heat preservation ends, turn off the heating device, cool down to room temperature, and then turn off the blower. Put the oxidized iron for trapping platinum group metals into an ultrasonic vibrating screen with mesh sizes of 20 mesh, 40 mesh, and 100 mesh, vibrate for 20 minutes respectively at a frequency of 18 kHz, perform magnetic separation on the mesh screens in sequence, and collect the iron oxide adsorbents and the residues containing platinum group metals.
[0053] Table 2 Main components of the adsorbent iron oxide obtained in Example 1
[0054] Component Fe Si Pt Pd Rh Content (wt%) 55.2 6.3 0.2 0.4 0.1
[0055] Table 3 Main components of the residue containing platinum group metal materials obtained in Example 1
[0056] Component Fe Si Pt Pd Rh Content (wt%) 31.8 5.1 3.8 23.2 4.7
[0057] From the data in Tables 1 - 3, it can be seen that the content of platinum group metals in the obtained materials containing platinum group metals is 31.7 wt%, and the content of platinum group metals has increased by 7 times compared with the iron for trapping platinum group metals. The content of platinum group metals in the obtained iron oxide is 0.7 wt%.
[0058] Example 2
[0059] Grind 50 g of iron for trapping platinum group metals, cut 60 g of the secondary resource of copper into pieces 1 - 1.5 cm in length, oxidize for 4 h, vibrate for 30 minutes respectively at a frequency of 18 kHz with different mesh screens, and other conditions are the same as in Example 1.
[0060] Table 4 Main components of the adsorbent iron oxide obtained in Example 2
[0061] Component Fe Si Pt Pd Rh Content (wt%) 57.3 7.2 0.1 0.5 0.2
[0062] Table 5 Main components of the residue containing platinum group metal materials obtained in Example 2
[0063] Component Fe Si Pt Pd Rh Content (wt%) 40.8 6.2 3.1 20.2 3.9
[0064] From the data in Tables 4 - 5, it can be seen that the content of platinum group metals in the obtained platinum group metal-containing material is 27.2 wt%, and the content of platinum group metals is 6 times higher than that of iron-captured platinum group metals. The content of platinum group metals in the obtained iron oxide is 0.8 wt%.
[0065] Comparative Example 1 (secondary resource without adding copper)
[0066] 30 g of iron-captured platinum group metals were ground and oxidized for 3.5 h. At a frequency of 18 kHz, different mesh sieves were vibrated for 30 minutes respectively, and other conditions were the same as in Example 1. No residue was obtained.
[0067] Main components of the adsorbed iron oxide in Table 6
[0068] Component Fe Si Pt Pd Rh Content (wt%) 56.8 6.5 0.1 1.2 0.2
[0069] From the data in Table 6, it can be seen that in the experiment of the secondary resource without adding copper, no residue was collected, and even the content of platinum group metals in the adsorbent decreased, indicating that the separation and enrichment of platinum group metals from iron were not achieved.
[0070] Combined with the data in Tables 1 - 5, it can be seen that increasing the dosage of copper and prolonging the oxidation time can further increase the content of platinum group metals in the platinum group metal-containing material.
[0071] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A method for enriching platinum group metals from iron capture of platinum group metals, characterized in that: The following steps are involved: Placing a control metal around the iron-captured platinum group metal, heating it for oxidation reaction, oxidizing the iron in the iron-captured platinum group metal into magnetic iron oxide, and removing the iron oxide to obtain enriched platinum group metal; the control metal has an affinity for oxygen less than iron and greater than platinum group metal; The temperature of the oxidation reaction is 350-450°C.
2. The method according to claim 1, characterized in that The controlling metal is a secondary resource containing copper; the copper content in the secondary resource containing copper is 80-90wt%.
3. The method according to claim 1 or 2, characterized in that: The mass ratio of the control metal to the iron-captured platinum group metal is ≥1:
1.
4. The method according to claim 1, characterized in that: The oxidation reaction is carried out under blowing conditions with a wind speed of 1000-1500 r / min.
5. The method according to claim 1 or 4, characterized in that: The oxidation reaction time is 3 to 5 hours.
6. The method according to claim 1, characterized in that The removal of iron oxides comprises: performing ultrasonic vibration screening and magnetic separation on the material after the oxidation reaction of iron-captured platinum group metals.
7. The method according to claim 6, characterized in that The frequency of the ultrasonic vibration screening is 15 to 20 kHz.
8. The method according to claim 6 or 7, characterized in that: The ultrasonic vibration screening includes sequentially performing a first screening, a second screening and a third screening; The first screening has a screening mesh number of 15 to 25 meshes; The second screening has a screening mesh number of 30 to 50 meshes; The third screening has a screening mesh number of 90 to 120 meshes.
9. The method according to claim 8, characterized in that The time of the first screening, the second screening and the third screening is independently 20 to 50 minutes.
10. The method according to claim 1, characterized in that The composition of the iron-captured platinum group metal includes 80-83wt% Fe, 8-12wt% Si, 0.3-0.8wt% Pt, 2.5-3.5wt% Pd, and 0.7-1.2wt% Rh.