A method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes

Abstract

The present invention relates to the field of metal recovery, and discloses a method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes. First, the scrapped spark plug electrodes are melt-cast into Ni-Pt-Ir alloy anode plates, and then electrolyzed to obtain cathode nickel and platinum-iridium anode mud; then aqua regia is used to dissolve the impurity metals and Pt in the platinum-iridium anode mud, and Ir powder and chloroplatinic acid solution are obtained by filtration; then ammonium chloride is added to the chloroplatinic acid solution, and ammonium chloroplatinate powder is obtained by precipitation and filtration; finally, ammonium chloroplatinate is calcined to obtain Pt powder. The present invention realizes efficient recovery and separation of Ni, Pt and Ir from scrapped spark plug electrodes, and has the advantages of short process, low material consumption, high metal recovery rate, high product purity, and easy industrialization, with Ni purity ≥99.0wt%, Pt and Ir purity ≥99.5wt%, and total metal recovery rate ≥98.0%.

Description

Technical Field

[0001] The invention belongs to the field of metal recovery and relates to a method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes. Background Art

[0002] Platinum and iridium are the most commonly used metals for spark plug electrode tip inserts, which are usually welded to the nickel alloy center and outer electrodes. They are scrapped due to oxidation, ablation, and fracture due to long-term service. my country is short of nickel, platinum, and iridium resources, with external dependence of 86%, 95%, and more than 95%, respectively. Therefore, recycling nickel, platinum, and iridium from scrapped spark plugs has significant economic value.

[0003] At present, the recovery method of valuable metals in spark plugs is mainly based on wet process, which has long process flow, low efficiency, low metal recovery rate, large amount of wastewater, and fails to achieve separation and recovery of Ni, Pt and Ir.

[0004] The Chinese invention patent (application number: CN201510677198.1) discloses a process for recovering copper and nickel from copper-nickel alloys. The copper-nickel alloy waste is melted, oxygen is blown to remove iron, and then cast into anode plates, electrolyzed to obtain cathode copper, and the electrolyte is evaporated and concentrated and centrifuged to obtain crude NiSO4. This process is simple and does not discharge wastewater, but the Ni recovery rate is less than 96%, and does not involve the recovery of Pt and Ir.

[0005] A Chinese invention patent (application number: CN201310673020.0) discloses a method for recovering copper and nickel from copper-nickel alloy waste. First, the nickel-iron-copper alloy waste is heated and melted, a slag-making agent is added and an oxidizing gas is sprayed to obtain molten metal and slag, and then the molten metal is cast into an anode plate, refined copper is first electrolyzed, and nickel is electrolyzed after further removing copper ions, and the acidity of the solution needs to be treated before electrolyzing nickel. The Ni purity of this process is >99.9%, but the process is complicated and produces a large amount of high-salt wastewater.

[0006] The Chinese invention patent (application number: CN202110832888.5) discloses a process for recovering precious metals in spark plugs. The electrode materials of waste spark plugs are gradually dissolved and filtered with HNO3, H2SO4, HCl, and aqua regia, and the filtrate is precipitated with NH4Cl, and the sponge platinum is obtained after hydrazine hydrate reduction; the filter residue is added to molten silver and dissolved in HNO3, and the metal powder is filtered, and finally the aqua regia is dissolved and filtered to obtain iridium powder. This method has a long production process, more than 15 steps, and produces a large amount of wastewater. Silver is used in the process of recovering iridium, which is costly and does not achieve Ni recovery.

[0007] A Chinese invention patent (application number: CN202111618645.8) discloses a method for separating platinum-iridium alloys. Use aqua regia to dissolve platinum-iridium alloy flakes, remove nitrate and acid, then add NaOH and an oxidant to separate Pt and Ir. The platinum-containing solution is precipitated with NH4Cl and reduced with hydrazine hydrate to obtain Pt powder. The iridium-containing filter cake is dissolved in HCl, precipitated with NH4Cl, dissolved in nitrite, and reduced with hydrogen to obtain Ir powder. This method is simple to operate, and the purity of the separated Pt powder and Ir powder is more than 99.95%, but the aqua regia needs to be treated with nitrate before precipitating Pt, which is seriously polluted, and Ir is extremely corrosion-resistant. The dissolution effect of aqua regia needs to be verified, and the Ir recovery rate is not good.

[0008] A Chinese invention patent (application number: CN202111158068.9) discloses a process for recovering platinum group metals from waste three-way catalysts. Use concentrated HCl+H2O2 to dissolve platinum group metals, detect the concentrations of Pt, Pd, and Rh in the filtrate, add metaphenylenediamine (MXDA) in proportion and step by step, and filter to obtain Pt-MXDA, Pd-MXDA, and Rh-MXDA precipitates, respectively, and then put them into a high-temperature and high-pressure reactor for high-temperature treatment to obtain Pt, Pd, and Rh. This method realizes the separation and recovery of Pt, Pd, and Rh, but Pt-MXDA is heated and decomposed to produce toxic gases, which pollute the environment.

[0009] In summary, the existing methods for recovering Ni, Pt and Ir have problems such as low recovery rate, complex process, large amount of wastewater, high material consumption and serious environmental pollution. It is difficult to combine the above methods to achieve the separation and coordinated recovery of Ni, Pt and Ir. Summary of the invention

[0010] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes, thereby achieving efficient separation and coordinated recovery of Ni, Pt and Ir. The present invention has simple operation, short process flow, low material consumption, low environmental burden, high recovery rate of valuable metals and is suitable for industrial production.

[0011] The present invention adopts the following technical solution:

[0012] A method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes, the method comprising the following steps:

[0013] S1. Melting and casting: The scrapped spark plug electrode material is melted and cast into a Ni-Pt-Ir alloy anode plate;

[0014] S2, electrolysis: using the Ni-Pt-Ir alloy plate obtained in step S1 as an anode, pure nickel as a cathode, and nickel sulfate and nickel chloride as electrolyte, electrolyzing in a diaphragm electrolytic cell to obtain cathode nickel and platinum-iridium anode mud;

[0015] S3, recovering Ir powder: dissolving the platinum-iridium anode mud in step S2 with aqua regia, and filtering to obtain Ir powder and chloroplatinic acid solution;

[0016] S4, recovering Pt powder: adding NH4Cl to the chloroplatinic acid solution in step S3 to generate ammonium chloroplatinate precipitate, and filtering to obtain ammonium chloroplatinate;

[0017] S5 and ammonium chloroplatinate are calcined to obtain Pt powder and NH4Cl tail gas, the NH4Cl tail gas is absorbed by water to obtain NH4Cl solution, the Pt powder is washed and filtered to obtain purified Pt powder, and the filtrate and the NH4Cl solution are returned to S4 to precipitate ammonium chloroplatinate.

[0018] Preferably, in step S1, the scrapped spark plug electrode material is melted at 1450-1600° C. for 0.5-3.0 h and cast into an alloy anode plate with a thickness of 5-30 mm.

[0019] Preferably, the electrolyte Ni in step S2 2+ 60-100g / L, Cl - 70-110g / L, SO4 2- It is 70-110g / L and pH is 2.0-5.0.

[0020] Preferably, in step S2, the Ni-Pt-Ir alloy anode plate is at room temperature -60°C, 1.8-2.2V, 200-300A / m 2 Electrolysis for 1.0-48.0h produces cathode nickel and platinum-iridium anode mud.

[0021] Preferably, the purity of cathode nickel in step S2 is not less than 99.0wt%.

[0022] Preferably, in step S3, the solid-liquid ratio of platinum-iridium anode mud to aqua regia is 1:5-1:15, dissolved at room temperature -90°C for 2.0-6.0h, and filtered to obtain Ir powder and chloroplatinic acid solution.

[0023] Preferably, the purity of the Ir powder in step S3 is not less than 99.5wt%.

[0024] Preferably, in step S4, 0.1-8.0 mol / L NH4Cl solution is added to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitate, which is filtered to obtain ammonium chloroplatinate.

[0025] Preferably, in step S5, ammonium chloroplatinate is calcined at 500-800° C. for 1.0-4.0 h to obtain Pt powder and NH4Cl tail gas, the NH4Cl tail gas is absorbed by water to obtain NH4Cl solution, the Pt powder is washed and filtered to obtain Pt powder with a purity of not less than 99.5wt%, and the filtrate and the NH4Cl solution are returned to S4 to precipitate ammonium chloroplatinate.

[0026] Preferably, the total recovery rate of Ni, Ir and Pt is not less than 98.0%.

[0027] The principle of the present invention is as follows:

[0028] (1) The standard electrode potential of Pt and Ir is greater than that of Ni and impurities Cr, Co, and Fe. Therefore, Ni and impurity elements dissolve into the electrolyte at the anode. In order to prevent impurities from precipitating at the cathode, a diaphragm must be used to separate the cathode and the cathode. After the anolyte is purified and impurities are removed, it enters the cathode area to precipitate Ni. Pt and Ir settle in a single state to form anode mud, realizing the separation of Ni from Pt and Ir. The electrolysis reaction is:

[0029] Anode: Ni-2e=Ni 2+ ; Cathode: Ni 2+ +2e=Ni

[0030] (2) Aqua regia can dissolve Pt in anode mud to form chloroplatinic acid solution, but aqua regia cannot dissolve Ir. The chemical reaction equation involved in the separation of Pt and Ir is as follows:

[0031] 3Pt+4HNO3+18HCl→3H2PtCl6+4NO↑+8H2O

[0032] (3) Chloroplatinic acid reacts with ammonium chloride to form ammonium chloroplatinate precipitate, which is then decomposed into Pt, HCl, NH4Cl and N2 upon heating. The chemical reaction equation involved is as follows:

[0033] H2PtCl6+2NH4Cl→(NH4)2PtCl6↓+2HCl

[0034]

[0035] The beneficial technical effects of the present invention include:

[0036] (1) The electrolysis, acid hydrolysis and precipitation methods are used to achieve the short-process collaborative recovery and separation of Ni, Ir and Pt from scrapped spark plug electrodes. Compared with the traditional process, the process is shortened by more than half, and the material consumption, energy consumption and emissions are reduced by more than 85%.

[0037] (2) Highly efficient separation and recovery of Ni was achieved through electrolysis, with Ni purity ≥ 99.0wt%;

[0038] (3) Taking advantage of the fact that Ir is resistant to corrosion by aqua regia, a mixture of Pt and Ir was dissolved in aqua regia to achieve efficient separation of Pt and Ir, with an Ir purity of ≥99.5wt%;

[0039] (4) Precipitating ammonium chloroplatinate with ammonium chloride can avoid the pollution caused by the process of removing nitrate from aqua regia, and has the characteristics of high impurity removal rate and easy operation;

[0040] (5) After calcination and washing, ammonium chloroplatinate can achieve a Pt purity of ≥99.5wt%, and the by-product NH4Cl can be recycled to precipitate ammonium chloroplatinate.

[0041] The invention realizes efficient recovery and separation of Ni, Pt and Ir from scrapped spark plug electrodes, and has the advantages of short process, low material consumption, high metal recovery rate, high product purity, easy industrialization, etc. The purity of Ni is ≥99.0%, the purity of Pt and Ir is ≥99.5wt%, and the total recovery rate of Ni, Ir and Pt is ≥98.0%. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 The present invention is a process flow chart of a method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes. DETAILED DESCRIPTION

[0044] The following will describe the technical solutions and technical problems solved in the embodiments of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0045] Example 1

[0046] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1450℃ for 3.0h and then cast to obtain a 30mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 100g / L, Cl - 110g / L, SO4 2- The pH value is 2.0, at 60°C, 1.8V, 300A / m 2 After electrolysis for 1.0 h, cathode nickel and platinum-iridium anode mud with a purity of 99.9 wt% were obtained.

[0047] At 90°C, aqua regia was used to dissolve platinum-iridium anode mud for 2.0 h, with a solid-liquid ratio of 1:5. After filtration, Ir powder with a purity of 99.5wt% and chloroplatinic acid solution were obtained.

[0048] Add 8.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 800°C for 1.0 h to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.5wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.0%.

[0049] Example 2

[0050] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1500℃ for 2.0h and then cast to obtain a 20mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 85g / L, Cl - 95g / L, SO4 2- The pH value is 3.0 and the temperature is 95 g / L. At 50 °C, the temperature is 1.9 V and 270 A / m 2 After electrolysis for 16.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.6 wt% were obtained.

[0051] At 80°C, aqua regia was used to dissolve platinum-iridium anode mud for 2.5 hours with a solid-liquid ratio of 1:7. After filtration, Ir powder with a purity of 99.6wt% and chloroplatinic acid solution were obtained.

[0052] Add 7.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 750°C for 1.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.6wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.1%.

[0053] Example 3

[0054] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1550℃ for 1.0h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 10mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 70g / L, Cl - 80g / L, SO4 2- 80g / L, pH 4.0, at 40°C, 2.0V, 240A / m 2 After 32.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.3 wt% were obtained.

[0055] At 70°C, aqua regia was used to dissolve platinum-iridium anode mud for 3.0 h, with a solid-liquid ratio of 1:9. After filtration, Ir powder with a purity of 99.7wt% and chloroplatinic acid solution were obtained.

[0056] Add 6.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 700°C for 2.0 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.7wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.2%.

[0057] Example 4

[0058] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1600℃ for 0.5h and then cast to obtain a 5mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 60g / L, Cl - 70g / L, SO4 2- The pH value was 70 g / L and 5.0. At room temperature, the 2 After 48.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.1 wt% were obtained.

[0059] At 60°C, aqua regia was used to dissolve platinum-iridium anode mud for 3.5 hours with a solid-liquid ratio of 1:11. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0060] Add 5.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 650°C for 2.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.8wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.3%.

[0061] Example 5

[0062] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1580℃ for 1.0h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 8mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 65g / L, Cl - 75g / L, SO4 2- The pH value is 5.0 and the temperature is 75 g / L at 30 °C.2 After 43.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.2 wt% were obtained.

[0063] At 50°C, aqua regia was used to dissolve platinum-iridium anode mud for 4.5 hours, with a solid-liquid ratio of 1:13. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0064] Add 4.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 600°C for 3.0 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.4%.

[0065] Example 6

[0066] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1560℃ for 1.5h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 11mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 70g / L, Cl - 80g / L, SO4 2- 80g / L, pH 4.5, at 35°C, 2.1V, 220A / m 2 After 38.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.2 wt% were obtained.

[0067] At room temperature, aqua regia was used to dissolve platinum-iridium anode mud for 6.0 h, with a solid-liquid ratio of 1:15. After filtration, Ir powder with a purity of 99.9 wt% and chloroplatinic acid solution were obtained.

[0068] Add 1.5 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 550°C for 3.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.5%.

[0069] Example 7

[0070] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1540℃ for 1.5h and then cast to obtain a 14mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 75g / L, Cl- 85g / L, SO4 2- 85g / L, pH 4.0, at 40°C, 2.0V, 230A / m 2 After 33.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.3 wt% were obtained.

[0071] At 35°C, aqua regia was used to dissolve platinum-iridium anode mud for 5.5 hours, with a solid-liquid ratio of 1:14. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0072] Add 0.1 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 500°C for 4.0 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.6%.

[0073] Example 8

[0074] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1520℃ for 2.0h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 16mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 78g / L, Cl - 88g / L, SO4 2- 88g / L, pH 3.5, at 45°C, 2.0V, 240A / m 2 After 28.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.4 wt% were obtained.

[0075] At 45°C, aqua regia was used to dissolve platinum-iridium anode mud for 5.0 h, with a solid-liquid ratio of 1:12. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0076] Add 0.5 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 520°C for 4.0 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.7%.

[0077] Example 9

[0078] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1500℃ for 2.0h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 19mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 80g / L, Cl - 90g / L, SO4 2- 90g / L, pH 3.0, at 50°C, 1.9V, 250A / m 2 After 24.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.4 wt% were obtained.

[0079] At 55°C, aqua regia was used to dissolve platinum-iridium anode mud for 4.5 hours with a solid-liquid ratio of 1:10. After filtration, Ir powder with a purity of 99.7wt% and chloroplatinic acid solution were obtained.

[0080] Add 1.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 540°C for 3.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.8%.

[0081] Example 10

[0082] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1480℃ for 2.5h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 22mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 85g / L, Cl - 95g / L, SO4 2- The pH value is 3.0 and the temperature is 95 g / L. At 55°C, the temperature is 1.9 V and 260 A / m 2 After electrolysis for 19.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.5wt% were obtained.

[0083] At 65°C, aqua regia was used to dissolve platinum-iridium anode mud for 4.0 h, with a solid-liquid ratio of 1:8. After filtration, Ir powder with a purity of 99.6wt% and chloroplatinic acid solution were obtained.

[0084] Add 2.5 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 560°C for 3.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.9%.

[0085] Embodiment 11

[0086] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1460℃ for 2.5h and then cast to obtain a 25mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 90g / L, Cl - 100g / L, SO4 2- The pH value is 2.5, at 55°C, 1.8V, 260A / m 2 After electrolysis for 14.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.6 wt% were obtained.

[0087] At 75°C, aqua regia was used to dissolve platinum-iridium anode mud for 3.0 h, with a solid-liquid ratio of 1:6. After filtration, Ir powder with a purity of 99.5wt% and chloroplatinic acid solution were obtained.

[0088] Add 3.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 580°C for 2.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 99.0%.

[0089] Example 12

[0090] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1450℃ for 3.0h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 28mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 95g / L, Cl - 105g / L, SO4 2- The pH value is 2.0 and the temperature is 105 g / L at 60 °C. 2 After electrolysis for 9.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.7wt% were obtained.

[0091] At 85°C, aqua regia was used to dissolve platinum-iridium anode mud for 2.5 hours with a solid-liquid ratio of 1:5. After filtration, Ir powder with a purity of 99.5wt% and chloroplatinic acid solution were obtained.

[0092] Add 3.5 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 600°C for 2.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 99.1%.

[0093] Embodiment 13

[0094] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1470℃ for 2.5h and then cast to obtain a 27mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 94g / L, Cl - 103g / L, SO4 2- The pH value is 2.5 and the temperature is 103 g / L. At 56°C, the temperature is 1.8 V and 280 A / m 2 After electrolysis for 2.0 h, cathode nickel and platinum-iridium anode mud with a purity of 99.8 wt% were obtained.

[0095] At 72°C, aqua regia was used to dissolve platinum-iridium anode mud for 3.0 h, with a solid-liquid ratio of 1:8. After filtration, Ir powder with a purity of 99.6wt% and chloroplatinic acid solution were obtained.

[0096] Add 4.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 620°C for 2.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.8wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 99.2%.

[0097] Embodiment 14

[0098] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1490℃ for 2.2h and then cast to obtain a 24mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 91g / L, Cl - 101g / L, SO4 2-The pH value is 2.5, and the temperature is 101 g / L at 52 °C. 2 After electrolysis for 9.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.7wt% were obtained.

[0099] At 62°C, aqua regia was used to dissolve platinum-iridium anode mud for 3.5 hours with a solid-liquid ratio of 1:11. After filtration, Ir powder with a purity of 99.7wt% and chloroplatinic acid solution were obtained.

[0100] Add 4.5 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 640°C for 2.0 h to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.8wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 99.3%.

[0101] Embodiment 15

[0102] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1510℃ for 2.0h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 21mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 85g / L, Cl - 97g / L, SO4 2- The pH value is 3.0 and the concentration is 97 g / L at 48 °C. 2 After electrolysis for 16.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.6 wt% were obtained.

[0103] At 52°C, aqua regia was used to dissolve platinum-iridium anode mud for 4.5 hours, with a solid-liquid ratio of 1:14. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0104] Add 5.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 660°C for 2.0 h to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.7wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 99.4%.

[0105] Example 16

[0106] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1530℃ for 1.8h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 18mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 80g / L, Cl - 92g / L, SO4 2- The pH value is 3.0 and the temperature is 92 g / L at 44 °C. 2 After 23.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.5wt% were obtained.

[0107] At room temperature, aqua regia was used to dissolve platinum-iridium anode mud for 5.5 h, with a solid-liquid ratio of 1:15. After filtration, Ir powder with a purity of 99.9 wt% and chloroplatinic acid solution were obtained.

[0108] Add 5.5 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 680°C for 2.0 h to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering to remove impurities is 99.7wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 99.5%.

[0109] Embodiment 17

[0110] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1550℃ for 1.5h and then cast to obtain a 15mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 75g / L, Cl - 87g / L, SO4 2- 87g / L, pH 3.5, at 40°C, 2.0V, 265A / m 2 After electrolysis for 30.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.5wt% were obtained.

[0111] At 47°C, aqua regia was used to dissolve platinum-iridium anode mud for 4.5 hours, with a solid-liquid ratio of 1:13. After filtration, Ir powder with a purity of 99.9wt% and chloroplatinic acid solution were obtained.

[0112] Add 6.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 700°C for 1.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.7wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.5%.

[0113] Embodiment 18

[0114] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1570℃ for 1.2h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 12mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 70g / L, Cl - 82g / L, SO4 2- 82g / L, pH 4.0, at 36°C, 2.1V, 245A / m 2 After 37.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.4 wt% were obtained.

[0115] At 52°C, aqua regia was used to dissolve platinum-iridium anode mud for 4.0 h, with a solid-liquid ratio of 1:11. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0116] Add 6.5 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 720°C for 1.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.6wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.6%.

[0117] Embodiment 19

[0118] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1590℃ for 0.8h and then cast to obtain a 9mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 65g / L, Cl - 77g / L, SO4 2- The pH value is 4.5 and the concentration is 77 g / L at 32°C at 2.1 V and 235 A / m 2 After 44.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.3 wt% were obtained.

[0119] At 57°C, aqua regia was used to dissolve platinum-iridium anode mud for 4.0 h, with a solid-liquid ratio of 1:10. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0120] Add 7.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 740°C for 1.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.6wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.7%.

[0121] Embodiment 20

[0122] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1600℃ for 0.5h and then cast to obtain a 6mm thick Ni-Ir-Pt alloy plate. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 60g / L, Cl - 72g / L, SO4 2- The pH value is 72g / L and 5.0. At room temperature, the 2 After 48.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.2 wt% were obtained.

[0123] At 62°C, aqua regia dissolved the platinum-iridium anode mud for 3.5 hours with a solid-liquid ratio of 1:9. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0124] Add 7.5 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 760°C for 2.0 h to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.5wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.8%.

[0125] Embodiment 21

[0126] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1580℃ for 0.7h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 8mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 64g / L, Cl - 75g / L, SO4 2- The pH value is 75g / L and 4.5. At room temperature, the2 After 40.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.2 wt% were obtained.

[0127] At 67°C, aqua regia was used to dissolve platinum-iridium anode mud for 3.5 hours with a solid-liquid ratio of 1:8. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0128] Add 8.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 780°C for 2.0 h to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering to remove impurities is 99.5wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.9%.

[0129] Embodiment 22

[0130] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1560℃ for 1.0h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 10mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 68g / L, Cl - 78g / L, SO4 2- The pH value is 4.5 and the temperature is 78 g / L at 31°C. 2 After 35.0 hours of electrolysis, cathode nickel and platinum-iridium anode mud with a purity of 99.3 wt% were obtained.

[0131] At 72°C, aqua regia was used to dissolve platinum-iridium anode mud for 3.0 h, with a solid-liquid ratio of 1:7. After filtration, Ir powder with a purity of 99.8wt% and chloroplatinic acid solution were obtained.

[0132] Add 8.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 800°C for 2.0 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 99.0%.

[0133] Embodiment 23

[0134] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1540℃ for 1.3h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 12mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+72g / L, Cl - 80g / L, SO4 2- 80g / L, pH 4.0, at 34°C, 2.0V, 225A / m 2 After electrolysis for 3.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.4wt% were obtained.

[0135] At 77°C, aqua regia was used to dissolve platinum-iridium anode mud for 2.5 hours with a solid-liquid ratio of 1:6. After filtration, Ir powder with a purity of 99.7wt% and chloroplatinic acid solution were obtained.

[0136] Add 7.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 770°C for 1.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.8wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.0%.

[0137] Embodiment 24

[0138] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1520℃ for 1.8h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 14mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 76g / L, Cl - 85g / L, SO4 2- 85g / L, pH 4.0, at 37°C, 1.9V, 235A / m 2 After electrolysis for 25.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.5wt% were obtained.

[0139] At 82°C, aqua regia was used to dissolve platinum-iridium anode mud for 2.5 hours with a solid-liquid ratio of 1:6. After filtration, Ir powder with a purity of 99.6wt% and chloroplatinic acid solution were obtained.

[0140] Add 6.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 740°C for 1.5 hours to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.8wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.1%.

[0141] Embodiment 25

[0142] The electrode material obtained by crushing and separating the scrapped spark plugs was melted at 1500℃ for 2.0h and then cast to obtain a Ni-Ir-Pt alloy plate with a thickness of 16mm. The Ni-Pt-Ir alloy plate was used as the anode and pure nickel was used as the cathode for electrolysis. 2+ 80g / L, Cl - 90g / L, SO4 2- 90g / L, pH 3.5, at 40°C, 1.8V, 245A / m 2 After electrolysis for 20.0 hours, cathode nickel and platinum-iridium anode mud with a purity of 99.6wt% were obtained.

[0143] At 90°C, aqua regia was used to dissolve platinum-iridium anode mud for 2.0 h, with a solid-liquid ratio of 1:5. After filtration, Ir powder with a purity of 99.5wt% and chloroplatinic acid solution were obtained.

[0144] Add 5.0 mol / L NH4Cl solution to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitation, which is filtered to obtain ammonium chloroplatinate and HCl solution. Ammonium chloroplatinate is calcined at 710°C for 2.0 h to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder after washing and filtering is 99.9wt%. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is reused to precipitate ammonium chloroplatinate. The total recovery rate of Ni, Ir and Pt is 98.2%.

Claims

1. A method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes, characterized in that: The method comprises the following steps: S1. Melting and casting: The scrapped spark plug electrode material is melted and cast into a Ni-Pt-Ir alloy anode plate; S2, electrolysis: using the Ni-Pt-Ir alloy plate obtained in step S1 as an anode, pure nickel as a cathode, and nickel sulfate and nickel chloride as electrolyte, electrolyzing in a diaphragm electrolytic cell to obtain cathode nickel and platinum-iridium anode mud; S3, recovering Ir powder: dissolving the platinum-iridium anode mud in step S2 with aqua regia, and filtering to obtain Ir powder and chloroplatinic acid solution; S4, recovering Pt powder: adding NH4Cl to the chloroplatinic acid solution in step S3 to generate ammonium chloroplatinate precipitate, and filtering to obtain ammonium chloroplatinate; S5 and ammonium chloroplatinate are calcined to obtain Pt powder and NH4Cl tail gas, the NH4Cl tail gas is absorbed by water to obtain NH4Cl solution, the Pt powder is washed and filtered to obtain purified Pt powder, and the filtrate and the NH4Cl solution are returned to S4 to precipitate ammonium chloroplatinate.

2. The method for recovering nickel, platinum and iridium from scrapped spark plug electrodes according to claim 1, characterized in that: In the step S1, the scrapped spark plug electrode material is melted at 1450-1600° C. for 0.5-3.0 hours and cast into an alloy anode plate with a thickness of 5-30 mm.

3. The method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes according to claim 1, characterized in that: In the step S2, the electrolyte: Ni 2+ 60-100g / L, Cl - 70-110g / L, SO4 2- The Ni-Pt-Ir alloy anode plate is 70-110g / L, pH is 2.0-5.0, and the Ni-Pt-Ir alloy anode plate is at room temperature -60℃, 1.8-2.2V, 200-300A / m 2 Electrolysis is performed for 1.0-48.0h to obtain cathode nickel and platinum-iridium anode mud with a purity of not less than 99.0wt%.

4. The method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes according to claim 1, characterized in that: In step S3, the solid-liquid ratio of platinum-iridium anode mud to aqua regia is 1:5-1:15, and the solution is dissolved at room temperature -90°C for 2.0-6.0 hours, and Ir powder and chloroplatinic acid solution with a purity of not less than 99.5wt% are obtained after filtration.

5. The method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes according to claim 1, characterized in that: In step S4, 0.1-8.0 mol / L NH4Cl solution is added to the chloroplatinic acid solution to generate ammonium chloroplatinate precipitate, which is filtered to obtain ammonium chloroplatinate and HCl solution.

6. The method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes according to claim 1, characterized in that: In the step S5, ammonium chloroplatinate is calcined at 500-800° C. for 1.0-4.0 h to obtain Pt powder and NH4Cl tail gas. The purity of the Pt powder is not less than 99.5wt% after washing and filtering to remove impurities. The NH4Cl tail gas is absorbed by the filtrate to obtain NH4Cl solution, which is returned to S4 to precipitate ammonium chloroplatinate.

7. The method for recovering and separating nickel, platinum and iridium from scrapped spark plug electrodes according to claim 1, characterized in that: The total recovery of Ni, Ir and Pt was ≥98.0%.

Images