A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy
Through a multi-step method, including efficient dephosphorization, deep iron removal and precise separation steps, the problem of difficult to efficiently separate palladium and platinum and rhodium from phosphorus-containing precious ferroalloys in the prior art is solved, and efficient precious metal recovery is achieved.
Patent Information
- Application Number
- CN202411654812.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-04-04
AI Technical Summary
The prior art is difficult to efficiently separate palladium and platinum and rhodium from phosphorus-containing noble ferroalloys through wet refining process. This is mainly because the phosphorus element reacts with the refining agent or solvent during the refining process to produce difficult-to-removal compounds, which affects the recovery rate of precious metals.
A multi-step approach is employed, including efficient dephosphorization, deep iron removal and precise separation steps. First, efficient removal of phosphorus is achieved by mixing sodium peroxide, sodium hydroxide and sulfur with phosphorus-containing ferroal alloys and calcining at high temperatures. Secondly, use hydrochloric acid and hydrogen peroxide to deeply remove iron to remove impurities from iron. Finally, efficient separation of palladium and platinum and rhodium is achieved through co-precipitation reaction and slurry steps.
The efficient separation of palladium and platinum and rhodium was achieved, with a separation efficiency of more than 99%, while the removal rate of phosphorus exceeded 98%, and the removal rate of iron reached more than 96%, which significantly improved the recovery rate of precious metals.
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Figure CN119753337A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of noble metal hydrometallurgy, and in particular relates to a method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys. Background Art
[0002] Precious metals mainly refer to platinum group metals including platinum, palladium, rhodium, iridium, etc., as well as gold and silver. Precious metal resources can be defined as primary resources and secondary resources, namely mineral precious metal resources and recycled precious metal resources. Precious secondary resources mainly refer to various available resources other than primary resources in nature, including waste generated during the production and manufacturing process, all materials containing recyclable precious metals that have partially or completely lost their original properties. Use precious metal secondary resources to make up for the shortage of mineral resources, ensure that mineral resources are not over-consumed, and realize the recycling and sustainable development of resources.
[0003] The secondary resource recovery of precious metals is mainly concentrated in the fields of waste jewelry, discarded electronic products, and automobile exhaust catalysts. They can be recovered by wet method, pyrolysis, or wet method combined with pyrolysis. The typical processing process is to produce precious iron alloys through electric arc furnace capture, and then achieve efficient recovery of platinum, palladium, and rhodium through wet refining. However, the phosphorus-containing precious iron alloys produced by electric arc furnace capture cannot be recovered through conventional wet refining processes. Because the phosphorus-containing precious iron alloys contain impurity elements such as phosphorus in addition to iron and precious metals, the presence of these elements makes the composition of the alloy complicated and increases the difficulty of wet refining. In particular, the phosphorus element may react with the refining agent or solvent during the wet refining process to form compounds that are difficult to remove, thereby affecting the recovery rate of precious metals. Summary of the invention
[0004] In view of the problems existing in the prior art, the present invention provides a method for efficiently separating palladium and platinum-rhodium from phosphorus-containing precious iron alloys, which can achieve efficient removal of phosphorus and iron in precious iron alloys produced by electric arc furnaces and efficient separation of palladium and platinum-rhodium. The phosphorus-containing precious iron alloys described in the present invention are phosphorus-containing precious iron alloys captured from recycled jewelry, discarded electronic products, etc. by electric arc furnaces.
[0005] The present invention specifically includes the following contents:
[0006] A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys comprises the following steps:
[0007] S1, efficient dephosphorization: sodium peroxide, sodium hydroxide, sulfur, and the phosphorus-containing noble iron alloy are mixed in a ratio of 1:(7-9):(2-4):(10-14) to obtain a mixture; the mixture is calcined at 400-500° C. to obtain a calcined material; water is added to the calcined material for leaching, and the leaching liquid is taken out to obtain a dephosphorized material;
[0008] S2, deep iron removal: adding a hydrochloric acid solution with a concentration of 3-6 mol / L to the dephosphorized material, and then adding hydrogen peroxide to carry out an iron removal reaction, and obtaining an iron-impregnated liquid and an iron-impregnated material after solid-liquid separation;
[0009] S3, precise separation: after the iron-impregnated material is dissolved (water-soluble chlorination or aqua regia dissolution can be adopted), sodium chlorate is added to the solution until the redox potential of the solution is greater than 800mv, and then a mixture of potassium chloride, ammonium chloride and tetramethylammonium chloride is added to the solution for co-precipitation reaction to obtain co-precipitated ammonium salts of palladium and platinum rhodium; the co-precipitated ammonium salts of palladium and platinum rhodium are slurried with pure water to obtain a slurry, the slurry is boiled and dissolved, and then the solid-liquid separation is performed to obtain a platinum rhodium material and a palladium stock solution.
[0010] Furthermore, the calcination time in step S1 is 10-14 hours.
[0011] Furthermore, the solid-liquid ratio of the leaching in step S1 is 1:(5-6); and / or the leaching temperature in step S1 is 55-65° C.; and / or the leaching time in step S1 is 3-5 h.
[0012] Furthermore, the solid-liquid ratio of the dephosphorization material to the hydrochloric acid solution in step S2 is 1:(5-6); and / or the mass concentration of the hydrogen peroxide in step S2 is 20%-30%, and the amount of hydrogen peroxide added is 0.4-0.6% of the total volume of the reaction system.
[0013] Furthermore, the temperature of the iron removal reaction is room temperature; and / or the time of the iron removal reaction is 4-8 hours.
[0014] Furthermore, the mixing mass ratio of potassium chloride, ammonium chloride and tetramethylammonium chloride in the mixture of step S3 is 1:(0.9-1.1):(4-6); and / or, the addition method of the mixture is: adding according to 1.1-1.2 times excess coefficient.
[0015] Furthermore, the solid-liquid ratio of the slurry in step S3 is 1:(7-9).
[0016] Furthermore, the boiling time in step S3 is 1.5-3h.
[0017] Furthermore, the separation efficiency of palladium from platinum and rhodium is >99%.
[0018] Furthermore, the removal rate of phosphorus in the dephosphorized material is greater than 98%; and / or the removal rate of iron in the iron-impregnated material is greater than or equal to 96%.
[0019] Beneficial effects of the present invention:
[0020] (1) The method disclosed in the present invention for efficiently separating palladium and platinum and rhodium from phosphorus-containing precious iron alloys is to solve the problem of the stability of the precious iron alloys produced by an electric arc furnace. Sodium peroxide: sodium hydroxide: sulfur: materials are uniformly mixed in a specific ratio, and the reaction temperature is controlled to be 400-500° C. in a muffle furnace. The materials are calcined at a constant temperature for a period of time to transform the alloy compound system of phosphorus and iron in the materials. After the materials are cooled and taken out of the furnace, water is added according to a specific solid-liquid ratio by utilizing the characteristic that the newly generated sodium phosphate is easily soluble in water. The materials are leached at a constant temperature of 55-65° C., thereby realizing one-step efficient water leaching dephosphorization.
[0021] (2) The method disclosed in the present invention for efficiently separating palladium and platinum and rhodium from phosphorus-containing precious iron alloys is to address the difficulty of leaching iron from precious iron alloys produced by electric arc furnaces. The dephosphorized material 1 obtained after efficient dephosphorization is added with 3-6 mol / L hydrochloric acid in proportion, and hydrogen peroxide is slowly and evenly added while stirring. After the addition is complete, the mixture is reacted at room temperature. The method achieves efficient leaching of iron by setting the iron removal process and parameters.
[0022] (3) The method disclosed in the present invention for efficiently separating palladium and platinum-rhodium from phosphorus-containing precious iron alloys is aimed at the difficulty that the ratio of palladium to other precious metals in the precious iron alloy produced by the electric arc furnace is large and the separation efficiency is poor. Sodium chlorate is added to the solution of the iron-leaching material until the redox potential reaches above 800mv, and a mixture of potassium chloride, ammonium chloride, and tetramethylammonium chloride is added according to a certain excess coefficient to react to generate a co-precipitated ammonium salt of palladium and platinum-rhodium; the solubility difference between palladium and platinum-rhodium is utilized to slurry the co-precipitated ammonium salt with pure water, and boiled until dissolved in a slightly boiling state to obtain platinum-rhodium material and palladium stock solution, thereby realizing a one-step efficient separation of palladium and platinum-rhodium. Using the method disclosed in the present invention, the separation efficiency of palladium and platinum-rhodium is greater than 99%, the removal rate of phosphorus is greater than 98%, and the removal rate of iron is ≥96%. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 The present invention is a schematic diagram of the process flow of the method disclosed in the present invention. DETAILED DESCRIPTION
[0024] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments shown below do not limit the invention content described in the claims. In addition, the entire contents of the structures represented by the following embodiments are not limited to those necessary as solutions to the invention described in the claims.
[0025] Reference Figure 1 , a method for efficiently separating palladium and platinum and rhodium from phosphorus-containing noble iron alloy, comprising the following steps:
[0026] S1, efficient dephosphorization: sodium peroxide, sodium hydroxide, sulfur, and the phosphorus-containing noble iron alloy are mixed in a ratio of 1:(7-9):(2-4):(10-14) to obtain a mixture; the mixture is calcined at 400-500° C. for 10-14 hours to obtain a calcined material; water is added to the calcined material at a solid-liquid ratio of 1:(5-6) for leaching, the leaching temperature is 55-65° C., the leaching time is 3-5 hours, and the leaching liquid is removed after the leaching is completed to obtain a dephosphorized material;
[0027] S2, deep iron removal: adding a hydrochloric acid solution with a concentration of 3-6 mol / L to the dephosphorized material at a solid-liquid ratio of 1:(5-6), and then adding a hydrogen peroxide solution with a mass concentration of 20%-30%, wherein the amount of hydrogen peroxide added is 0.4-0.6% of the total volume of the reaction system, and performing an iron removal reaction at room temperature for 4-8 hours. After the reaction is completed, the solid and liquid are separated to obtain an iron-impregnated liquid and an iron-impregnated material;
[0028] S3, precise separation: after the iron-impregnated material is dissolved, sodium chlorate is added to the solution until the redox potential of the solution is greater than 800mv, and then a mixture of potassium chloride, ammonium chloride and tetramethylammonium chloride is added to the solution at an excess coefficient of 1.1-1.2 times, wherein the mass ratio of potassium chloride, ammonium chloride and tetramethylammonium chloride in the mixture is 1:(0.9-1.1):(4-6), and a co-precipitation reaction is carried out to obtain a co-precipitated ammonium salt of palladium and platinum rhodium; the co-precipitated ammonium salt of palladium and platinum rhodium is slurried with pure water at a solid-liquid ratio of 1:(7-9) to obtain a slurry, and the slurry is boiled for 1.5-3h to dissolve the palladium, and finally the solid-liquid is separated to obtain a platinum rhodium material and a palladium stock solution.
[0029] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is greater than 99%, the removal rate of phosphorus is greater than 98%, and the removal rate of iron is greater than or equal to 96%.
[0030] Example 1
[0031] A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys comprises the following steps:
[0032] S1, efficient dephosphorization: take 500g of precious iron alloy produced by the electric arc furnace, and mix sodium peroxide: sodium hydroxide: sulfur: material in a ratio of 1:8:3:12, place it in a muffle furnace, control the reaction temperature to 450°C, calcine at a constant temperature for 12h, obtain 653g of leached material, add 3.3L of water, and leach at 60°C with constant temperature stirring for 4h to achieve one-step efficient water leaching dephosphorization, and obtain dephosphorization material 1 with a wet weight of 303g.
[0033] S2, deep iron removal: add 1.6L of 3.5mol / L hydrochloric acid to 303g of dephosphorized material 1 obtained after efficient dephosphorization in S1, and slowly and evenly add 8ml of 20% hydrogen peroxide with a total volume while stirring. After the addition is complete, react at room temperature for 6h to obtain 78g of iron-impregnated material 1 with a wet weight of 78g.
[0034] S3, precise separation: after dissolving the iron-impregnated material 1, sodium chlorate is added to 450 mL of the solution obtained until the redox potential reaches 860 mv, and 44.85 g of potassium chloride, ammonium chloride and tetramethylammonium chloride mixed in proportion are added to react to generate 108 g of co-precipitated ammonium salt of palladium and platinum rhodium; utilizing the solubility difference between palladium and platinum rhodium, the co-precipitated ammonium salt is slurried with pure water at a solid-liquid ratio of 1:8, boiled to dissolve in a slightly boiling state for 2 hours, and 54 g of platinum-rhodium material and 860 mL of palladium stock solution are obtained, thereby realizing one-step efficient separation of palladium and platinum rhodium.
[0035] Example 2
[0036] A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys comprises the following steps:
[0037] S1, efficient dephosphorization: take 3000g of precious iron alloy produced by electric arc furnace, and mix sodium peroxide: sodium hydroxide: sulfur: material in the ratio of 1:8:3:12, place in a muffle furnace, control the reaction temperature to 480℃, calcine at constant temperature for 12h, obtain 3975g of leached material, add 23L of water, stir and leach at constant temperature for 4h at 60℃, realize one-step efficient water leaching dephosphorization, and obtain dephosphorization material 1 with a wet weight of 1765g.
[0038] S2, deep iron removal: add 9L of 4mol / L hydrochloric acid to 1765g of dephosphorized material 1 obtained after efficient dephosphorization in S1, and slowly and evenly add 45ml of 30% hydrogen peroxide with a total volume while stirring. After the addition is complete, react at room temperature for 6h to obtain 513g of iron-impregnated material 1 with a wet weight of 1.
[0039] S3, precise separation: after dissolving the iron-impregnated material 1, sodium chlorate is added to 3500 mL of the solution obtained until the redox potential reaches 860 mv, and 281.35 g of potassium chloride, ammonium chloride and tetramethylammonium chloride mixed in proportion are added to react to generate 723 g of co-precipitated ammonium salt of palladium and platinum rhodium; utilizing the solubility difference between palladium and platinum rhodium, the co-precipitated ammonium salt is slurried with pure water at a solid-liquid ratio of 1:8, boiled until dissolved in a slightly boiling state for 2 hours, and 378 g of platinum rhodium material and 5800 mL of palladium stock solution are obtained, thereby realizing one-step efficient separation of palladium and platinum rhodium.
[0040] Example 3
[0041] A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys comprises the following steps:
[0042] S1, efficient dephosphorization: take 800g of precious iron alloy produced by electric arc furnace, and mix sodium peroxide: sodium hydroxide: sulfur: material in the ratio of 1:8:3:12, place in a muffle furnace, control the reaction temperature to 430℃, calcine at constant temperature for 12h, obtain 1059.6g of leached material, add 6L of water, stir and leach at constant temperature for 4h at 60℃, realize one-step efficient water leaching dephosphorization, and obtain dephosphorization material 1 with a wet weight of 501g.
[0043] S2, deep iron removal: add 3L of 3.2mol / L hydrochloric acid to 501g of dephosphorized material 1 obtained after efficient dephosphorization in S1, and slowly and evenly add 15ml of 25% hydrogen peroxide with a total volume while stirring. After the addition is complete, react at room temperature for 6h to obtain an iron-impregnated material 1 with a wet weight of 118.2g.
[0044] S3, precise separation: after dissolving the iron-impregnated material 1, sodium chlorate is added to 580 mL of the solution obtained until the redox potential reaches 860 mv, and 68.39 g of potassium chloride, ammonium chloride and tetramethylammonium chloride mixed in proportion are added to react to generate 156.32 g of co-precipitated ammonium salt of palladium and platinum rhodium; utilizing the solubility difference between palladium and platinum rhodium, the co-precipitated ammonium salt is slurried with pure water at a solid-liquid ratio of 1:8, boiled to dissolve in a slightly boiling state for 2 hours, and 78.5 g of platinum-rhodium material and 1250 mL of palladium stock solution are obtained, thereby realizing one-step efficient separation of palladium and platinum rhodium.
[0045] Example 4
[0046] A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys comprises the following steps:
[0047] S1, efficient dephosphorization: sodium peroxide, sodium hydroxide, sulfur, and the phosphorus-containing noble iron alloy are mixed in a ratio of 1:7:2:10 to obtain a mixture; the mixture is calcined at 400° C. for 10 hours to obtain a calcined material; water is added to the calcined material at a solid-liquid ratio of 1:5 for leaching, the leaching temperature is 55° C., the leaching time is 3 hours, and the leaching liquid is removed after the leaching is completed to obtain a dephosphorized material;
[0048] S2, deep iron removal: adding a 3 mol / L hydrochloric acid solution to the dephosphorized material at a solid-liquid ratio of 1:5, and then adding a 22% mass concentration of hydrogen peroxide, wherein the amount of hydrogen peroxide added is 0.4% of the total volume of the reaction system, and performing an iron removal reaction at room temperature for 4 hours. After the reaction is completed, the solid and liquid are separated to obtain an iron-impregnated liquid and an iron-impregnated material;
[0049] S3, precise separation: after the iron-impregnated material is dissolved, sodium chlorate is added to the solution until the redox potential of the solution is greater than 820mv, and then a mixture of potassium chloride, ammonium chloride and tetramethylammonium chloride is added to the solution at an excess coefficient of 1.1 times, wherein the mixing ratio of potassium chloride, ammonium chloride and tetramethylammonium chloride in the mixture is 1:0.9:4, and a co-precipitation reaction is carried out to obtain a co-precipitated ammonium salt of palladium and platinum rhodium; the co-precipitated ammonium salt of palladium and platinum rhodium is slurried with pure water at a solid-liquid ratio of 1:7 to obtain a slurry, and the slurry is boiled for 1.5h to dissolve the palladium, and finally the solid-liquid is separated to obtain a platinum rhodium material and a palladium stock solution.
[0050] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 99.1%, the removal rate of phosphorus is 98.2%, and the removal rate of iron is 96%.
[0051] Example 5
[0052] A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys comprises the following steps:
[0053] S1, efficient dephosphorization: sodium peroxide, sodium hydroxide, sulfur, and the phosphorus-containing precious iron alloy are mixed in a ratio of 1:9:4:14 to obtain a mixture; the mixture is calcined at 500° C. for 14 hours to obtain a calcined material; water is added to the calcined material at a solid-liquid ratio of 1:6 for leaching, the leaching temperature is 65° C., the leaching time is 5 hours, and the leaching liquid is removed after the leaching is completed to obtain a dephosphorized material;
[0054] S2, deep iron removal: adding a 6 mol / L hydrochloric acid solution to the dephosphorized material at a solid-liquid ratio of 1:6, and then adding a 26% mass concentration of hydrogen peroxide, wherein the amount of hydrogen peroxide added is 0.6% of the total volume of the reaction system, and performing an iron removal reaction at room temperature for 8 hours. After the reaction is completed, the solid and liquid are separated to obtain an iron-impregnated liquid and an iron-impregnated material;
[0055] S3, precise separation: after the iron-impregnated material is dissolved, sodium chlorate is added to the solution until the redox potential of the solution is greater than 850mv, and then a mixture of potassium chloride, ammonium chloride and tetramethylammonium chloride is added to the solution at an excess coefficient of 1.2 times, wherein the mixing ratio of potassium chloride, ammonium chloride and tetramethylammonium chloride in the mixture is 1:1.1:6, and a co-precipitation reaction is carried out to obtain a co-precipitated ammonium salt of palladium and platinum rhodium; the co-precipitated ammonium salt of palladium and platinum rhodium is slurried with pure water at a solid-liquid ratio of 1:9 to obtain a slurry, and the slurry is boiled for 3 hours to dissolve the palladium, and finally the solid-liquid is separated to obtain a platinum rhodium material and a palladium stock solution.
[0056] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 99.7%, the removal rate of phosphorus is 99%, and the removal rate of iron is 97.3%.
[0057] Example 6
[0058] A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys comprises the following steps:
[0059] S1, efficient dephosphorization: sodium peroxide, sodium hydroxide, sulfur, and the phosphorus-containing precious iron alloy are mixed in a ratio of 1:8:3:12 to obtain a mixture; the mixture is calcined at 450° C. for 12 hours to obtain a calcined material; water is added to the calcined material at a solid-liquid ratio of 1:5.5 for leaching, the leaching temperature is 60° C., the leaching time is 4 hours, and the leaching liquid is removed after the leaching is completed to obtain a dephosphorized material;
[0060] S2, deep iron removal: adding a 5 mol / L hydrochloric acid solution to the dephosphorized material at a solid-liquid ratio of 1:5.5, and then adding a 30% mass concentration of hydrogen peroxide, wherein the amount of hydrogen peroxide added is 0.5% of the total volume of the reaction system, and performing an iron removal reaction at room temperature for 6 hours. After the reaction is completed, the solid and liquid are separated to obtain an iron-impregnated liquid and an iron-impregnated material;
[0061] S3, precise separation: after the iron-impregnated material is dissolved, sodium chlorate is added to the solution until the redox potential of the solution is greater than 800mv, and then a mixture of potassium chloride, ammonium chloride and tetramethylammonium chloride is added to the solution at an excess coefficient of 1.15 times, wherein the mixing ratio of potassium chloride, ammonium chloride and tetramethylammonium chloride in the mixture is 1:1:5, and a co-precipitation reaction is carried out to obtain a co-precipitated ammonium salt of palladium and platinum rhodium; the co-precipitated ammonium salt of palladium and platinum rhodium is slurried with pure water at a solid-liquid ratio of 1:8 to obtain a slurry, and the slurry is boiled for 2h to dissolve the palladium, and finally the solid-liquid is separated to obtain a platinum rhodium material and a palladium stock solution.
[0062] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 99.9%, the removal rate of phosphorus is 99%, and the removal rate of iron is 97.8%.
[0063] Comparative Example 1
[0064] The difference between this comparative example and Example 6 is that the mixing ratio of sodium peroxide, sodium hydroxide, sulfur and the phosphorus-containing precious iron alloy is 1:6:3:12, and the other conditions are the same.
[0065] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 96.2%, the removal rate of phosphorus is 94%, and the removal rate of iron is 95.3%.
[0066] Comparative Example 2
[0067] The difference between this comparative example and Example 6 is that the mixing ratio of sodium peroxide, sodium hydroxide, sulfur and the phosphorus-containing precious iron alloy is 1:8:5:12, and the other conditions are the same.
[0068] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 97.6%, the removal rate of phosphorus is 95%, and the removal rate of iron is 95.7%.
[0069] Comparative Example 3
[0070] The difference between this comparative example and Example 6 is that the mixing ratio of sodium peroxide, sodium hydroxide, sulfur and the phosphorus-containing precious iron alloy is 1:8:3:15, and the other conditions are the same.
[0071] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 97.9%, the removal rate of phosphorus is 94.7%, and the removal rate of iron is 95.6%.
[0072] Comparative Example 4
[0073] The difference between this comparative example and Example 6 is that the concentration of hydrochloric acid used in step S2 is 2 mol / L, and the other conditions are the same.
[0074] According to the test, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 95.1%, the removal rate of phosphorus is 99%, and the removal rate of iron is 93.1%.
[0075] Comparative Example 5
[0076] The difference between this comparative example and Example 6 is that the concentration of hydrochloric acid used in step S2 is 8 mol / L, and the other conditions are the same.
[0077] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 95.4%, the removal rate of phosphorus is 98.9%, and the removal rate of iron is 95.5%.
[0078] Comparative Example 5
[0079] The difference between this comparative example and Example 6 is that: in step S3, sodium chlorate is added to the dissolving solution until the redox potential of the solution is 750 mv, and the other conditions are the same.
[0080] According to tests, by using the method disclosed in the present invention, the separation efficiency of palladium and platinum and rhodium is 96.2%, the removal rate of phosphorus is 98.7%, and the removal rate of iron is 97.6%.
[0081] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloys, characterized in that: The following steps are involved: S1, efficient dephosphorization: sodium peroxide, sodium hydroxide, sulfur, and the phosphorus-containing noble iron alloy are mixed in a ratio of 1:(7-9):(2-4):(10-14) to obtain a mixture; the mixture is calcined at 400-500° C. to obtain a calcined material; water is added to the calcined material for leaching, and the leaching liquid is taken out to obtain a dephosphorized material; S2, deep iron removal: adding a hydrochloric acid solution with a concentration of 3-6 mol / L to the dephosphorized material, and then adding hydrogen peroxide to carry out an iron removal reaction, and obtaining an iron-impregnated liquid and an iron-impregnated material after solid-liquid separation; S3, precise separation: after the iron-impregnated material is dissolved, sodium chlorate is added to the solution until the redox potential of the solution is greater than 800mv, and then a mixture of potassium chloride, ammonium chloride and tetramethylammonium chloride is added to the solution for co-precipitation reaction to obtain co-precipitated ammonium salts of palladium and platinum rhodium; the co-precipitated ammonium salts of palladium and platinum rhodium are slurried with pure water to obtain a slurry, the slurry is boiled and dissolved, and then the solid-liquid separation is performed to obtain a platinum rhodium material and a palladium stock solution.
2. A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy according to claim 1, characterized in that: The calcination time in step S1 is 10-14 hours.
3. The method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy according to claim 1, characterized in that: The solid-liquid ratio of the leaching in step S1 is 1:(5-6); and / or, the leaching temperature in step S1 is 55-65° C.; and / or, the leaching time in step S1 is 3-5 h.
4. A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy according to claim 1, characterized in that: The solid-liquid ratio of the dephosphorized material to the hydrochloric acid solution in step S2 is 1:(5-6); and / or the mass concentration of the hydrogen peroxide in step S2 is 20%-30%, and the amount of hydrogen peroxide added is 0.4-0.6% of the total volume of the reaction system.
5. A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy according to claim 4, characterized in that: The temperature of the iron removal reaction is room temperature; and / or the time of the iron removal reaction is 4-8 hours.
6. A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy according to claim 1, characterized in that: The mixing mass ratio of potassium chloride, ammonium chloride and tetramethylammonium chloride in the mixture of step S3 is 1:(0.9-1.1):(4-6); and / or, the addition method of the mixture is: adding according to 1.1-1.2 times excess coefficient.
7. A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy according to claim 6, characterized in that: The solid-liquid ratio of the slurry in step S3 is 1:(7-9).
8. A method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy according to claim 7, characterized in that: The boiling time in step S3 is 1.5-3h.
9. The method for efficiently separating palladium and platinum-rhodium from phosphorus-containing noble iron alloy according to any one of claims 1 to 8, characterized in that: The separation efficiency of palladium from platinum and rhodium is >99%.
10. A method for efficiently separating palladium and platinum and rhodium from phosphorus-containing noble iron alloy according to claim 9, characterized in that: The phosphorus removal rate in the dephosphorized material is greater than 98%; and / or the iron removal rate in the iron-impregnated material is greater than or equal to 96%.