Preparation process of iridium trichloride

Abstract

The invention belongs to the field of noble metal compounds, and discloses a preparation process of iridium trichloride, which comprises the following steps: mixing ammonium chloroiridate and aqua regia, heating for reaction, then sequentially concentrating and removing nitrate, adding absolute ethyl alcohol for primary reduction, adding absolute ethyl alcohol for secondary reduction, and filtering to obtain solid particles, namely iridium trichloride. The iridium trichloride is prepared by a step-by-step reduction method, so that the formation of byproducts can be reduced, and the high-purity iridium trichloride can be obtained by a simple process. The preparation method provided by the invention has the excellent effects of simple process, short production time and high purity of the prepared iridium trichloride, the reaction conditions are easy to control, the reaction is smooth, the product quality consistency is high during mass production, and industrialization and marketization are facilitated.

Description

Technical Field

[0001] The invention belongs to the field of precious metal compounds and relates to the preparation of precious metal iridium compounds, in particular to a preparation process of iridium trichloride. Background Art

[0002] Iridium trichloride has a wide range of uses. It can accelerate hydrogenation and oxidation reactions and is an indispensable catalyst in pharmaceuticals and fine chemicals. It can be used as an electrode material, showing excellent stability and conductivity. It can also construct complex molecular structures, especially in asymmetric synthesis.

[0003] Patent CN106854001A discloses a controlled reduction preparation method of iridium trichloride, wherein tetravalent iridium chloride and a reducing agent are added to a three-necked flask placed in a constant temperature water bath in a certain proportion, wherein the reducing agent is composed of an acid reducing agent, an alcohol reducing agent and a hydrazine reducing agent. The reaction is promoted by introducing a special reducing agent, but the complex reducing agent components not only increase the cost, but also make the subsequent product separation and purification process extremely complicated. Too many types of reagents introduced during the production process are likely to cause reagent residues, affecting the purity of the product.

[0004] Patent CN114105229A discloses a method for preparing high-purity iridium trichloride, using iridium powder as raw material, alkali melting, aqua regia dissolution, ammonium chloride precipitation, sodium sulfide and ammonium sulfide removal, oxidant oxidation, and ammonium chloride solution precipitation to obtain higher purity ammonium chloroiridate. Expensive and difficult to obtain reagents are used in the reaction process, which greatly increases the production cost; at the same time, there are complex process steps, and the reaction conditions are difficult to accurately control, resulting in low production efficiency and a long production cycle of about 3-5 days per batch. Moreover, due to the incomplete removal of impurities during the reaction process, the product purity is low, usually only about 98%, which is difficult to meet the high purity of iridium trichloride in high-end electronics, chemical and other industries. Summary of the invention

[0005] In view of the defects and shortcomings of the prior art, the present invention provides a method for preparing iridium trichloride.

[0006] A method for preparing iridium trichloride comprises the following steps: Step 1, mixing ammonium chloroiridate and aqua regia, heating for reaction and then cooling to obtain liquid A; Step 2, heating liquid A until a large amount of yellow smoke appears, adding hydrochloric acid, and then continuing to heat and rotary evaporate to remove the nitrate until no yellow smoke appears, and then continuing to concentrate until no liquid is recovered in the condenser tube, and then cooling and filtering in sequence to obtain the nitrate-removing liquid; Step 3, mixing the nitrate-removing liquid and anhydrous ethanol, heating for reaction and then cooling to obtain liquid B; Step 4, mixing solution B and anhydrous ethanol, heating for reaction, cooling, and then concentrating and drying to obtain solid particles, namely iridium trichloride.

[0007] Preferably, in step 1, the solid-to-liquid ratio of ammonium chloroiridate and aqua regia used in preparing liquid A is 1 kg: 3-5 L.

[0008] Preferably, in step 1, the reaction temperature is 90-100° C. and the reaction time is 3-4 h.

[0009] Preferably, in step 2, the heating temperature is 100-110°C.

[0010] Preferably, the molar ratio of the hydrochloric acid added in step 2 to the nitrate ions in liquid A is 0.6-0.8:1, and the mass fraction of the hydrochloric acid is 30%-36%.

[0011] Preferably, in step 3, when the nitrate-removing solution and anhydrous ethanol are mixed, the molar ratio of iridium ions in the nitrate-removing solution to anhydrous ethanol is 1:1.38-2.31.

[0012] Preferably, in step 3, the heating temperature is 105-110° C. and the heating time is 5-10 min.

[0013] Preferably, after step 3 and before step 4, a concentration step is further included, wherein liquid B is heated to 100-110° C. and concentrated until solidified.

[0014] Preferably, in step 4, when liquid B and anhydrous ethanol are mixed, the molar ratio of iridium ions in liquid B to anhydrous ethanol is 1:0.69-1.15.

[0015] Preferably, in step 3, the heating temperature is 90-100° C. and the heating time is 10-15 min.

[0016] Compared with the prior art, the present invention has the following obvious beneficial effects: The preparation of iridium trichloride by a step-by-step reduction method can reduce the formation of by-products, and high-purity iridium trichloride can be obtained by a simple process. The preparation method provided by the present invention has the advantages of simple process, short production time, and high purity of the prepared iridium trichloride, and the reaction conditions are easy to control, the reaction is gentle, and the product quality consistency is high when mass production is carried out, which is conducive to industrialization and marketization. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the XPS spectrum of iridium trichloride prepared in Example 1; Figure 2 This is the XPS energy spectrum of iridium trichloride prepared in Comparative Example 1. DETAILED DESCRIPTION

[0018] The present invention provides the following specific technical solutions.

[0019] A method for preparing iridium trichloride comprises the following steps: Step 1, mixing ammonium chloroiridate and aqua regia, heating for reaction and then cooling to obtain liquid A; Step 2, heating liquid A until a large amount of yellow smoke appears, adding hydrochloric acid, and then continuing to heat and rotary evaporate to remove the nitrate until no yellow smoke appears, and then continuing to concentrate until no liquid is recovered in the condenser tube, and then cooling and filtering in sequence to obtain the nitrate-removing liquid; Step 3, mixing the nitrate-removing liquid and anhydrous ethanol, heating for reaction and then cooling to obtain liquid B; Step 4, mixing solution B and anhydrous ethanol, heating for reaction, cooling, and then concentrating and drying to obtain solid particles, namely iridium trichloride.

[0020] The inventors have found through research that the preparation of iridium trichloride by a step-by-step reduction method can reduce the formation of by-products, and high-purity iridium trichloride can be obtained by a simple process. The preparation method provided by the present invention has the advantages of simple process, short production time, and high purity of the obtained iridium trichloride, and the reaction conditions are easy to control, the reaction is gentle, and the product quality consistency is high when mass production is carried out, which is conducive to industrialization and marketization.

[0021] After adding hydrochloric acid, the nitric acid in liquid A is removed by rotary evaporation, and then the concentration is continued until no liquid is recovered in the condenser. The hydrochloric acid in the solution is removed by the concentration process, which is beneficial to the subsequent reduction of iridium ions. In practical applications, the concentration state can be judged by touching the temperature of the outer wall of the condenser. If the touch of the outer wall of the condenser is room temperature, the heating can be stopped and the concentration is completed.

[0022] Preferably, in step 1, the solid-to-liquid ratio of the iridium material and aqua regia in liquid A is 1 kg: 3-5 L.

[0023] In practical applications, the volume ratio of hydrochloric acid to nitric acid in the aqua regia used in the present invention is 3:1; when preparing the aqua regia, the mass fraction of nitric acid used is 60%-65%, and the mass fraction of hydrochloric acid used is 30%-36%.

[0024] Preferably, in step 1, the reaction temperature is 90-100° C. and the reaction time is 3-4 h.

[0025] Preferably, in step 2, the heating temperature is 100-110°C.

[0026] Preferably, in step 2, the molar ratio of the hydrochloric acid added in step 2 to the nitrate ions in liquid A is 0.6-0.8:1, and the mass fraction of the hydrochloric acid is 30%-36%.

[0027] Preferably, in step 3, the molar ratio of iridium ions to anhydrous ethanol in the mixed solution A is 1:1.38-2.31.

[0028] Preferably, in step 3, the heating temperature is 105-110° C. and the heating time is 5-10 min.

[0029] The inventors have found through research that, firstly, adding excess ethanol in the first stage of reduction can ensure the presence of sufficient reducing agent in the reaction system. Combined with the reaction temperature, most of the tetravalent iridium can be reduced to trivalent iridium in a shorter time, and the possibility of the formation of by-products (tetravalent iridium and iridium element) is reduced.

[0030] Preferably, after step 3 and before step 4, a concentration step is further included, in which liquid B is heated to 90-100° C. and concentrated until solidified.

[0031] Preferably, in step 4, the molar ratio of iridium ions to anhydrous ethanol in the mixed solution B is 1:0.69-1.15.

[0032] Preferably, in step 4, the heating temperature is 90-100° C. and the heating time is 10-15 min.

[0033] The inventors have found through research that most of the iridium ions are converted into trivalent ions after the first reduction, and the amount of reducing agent and the reaction temperature are reduced during the second reduction, thereby reducing the reaction rate, avoiding the generation of by-products (iridium elemental substance), and prolonging the reaction time to ensure that the tetravalent iridium is completely converted into trivalent iridium. The present invention reduces iridium ions in a solution state, and the reduction state is more controllable, which can further avoid the generation of by-products and improve the yield of trivalent iridium. The reduction solution is concentrated before the first reduction and the second reduction, and hydrochloric acid volatilizes during the concentration process to create conditions conducive to reduction (the presence of hydrochloric acid will hinder the forward reaction).

[0034] In actual operation, the temperature during the second reduction is about 10°C lower than that during the first reduction.

[0035] In order to make the technical problems, technical solutions and technical advantages to be solved by the present invention more clear, they will be described in detail below with reference to specific examples, but the protection scope of the present invention is not limited to the following specific embodiments.

[0036] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0038] Embodiment 1: A method for preparing iridium trichloride comprises the following steps: Step 1, mixing 3kg of ammonium chloroiridate and 9L of aqua regia, heating to 95°C for reaction for 3.5h and then cooling to obtain liquid A, wherein the volume ratio of hydrochloric acid to nitric acid in the aqua regia is 3:1; the mass fraction of hydrochloric acid used in the preparation of the aqua regia is 36%, and the mass fraction of nitric acid is 65%.

[0039] Step 2, transfer the liquid A obtained in step 1 to an evaporator, set the heating temperature to 100°C for concentration, and when a large amount of yellow smoke is observed in the condensation column, add 2.25L of hydrochloric acid with a concentration of 36%, continue to heat and rotary evaporate to drive out the nitrate, until no yellow smoke is generated, then continue to concentrate to drive out excess hydrochloric acid, when there is no liquid reflux in the condenser and the temperature of the outer wall of the condenser is room temperature, it can be determined that the excess hydrochloric acid has been removed, then stop concentrating, and naturally cool for 1 hour to obtain the nitrate-removing liquid.

[0040] Step 3, transferring the nitrate-removing solution obtained in step 2 to a PP filter for filtering to remove insoluble impurities in the nitrate-removing solution to obtain a chloroiridic acid solution.

[0041] Step 4, testing the metal content of the chloroiridic acid solution, and adding distilled water to adjust the iridium ion content in the solution to 35% according to the test result.

[0042] Step 5, mixing 4 kg of the chloroiridic acid solution prepared in step 3, 4 L of water and 0.6 L of anhydrous ethanol, heating to 110° C., reacting for 10 min and then cooling to obtain liquid B.

[0043] Step 6, transferring the liquid B obtained in step 5 to an evaporator, heating it to 100° C. for concentration, and concentrating it until solidified to obtain an intermediate product.

[0044] Step 7, mixing the intermediate product obtained in step 6 with 4 L of water, then heating to 110° C., stirring until the intermediate product is completely dissolved in the water, then cooling to 60° C., adding 0.3 L of anhydrous ethanol, mixing evenly, heating to 100° C. and heating for 15 min, then cooling and filtering to obtain an iridium trichloride solution.

[0045] Step 8, transferring the iridium trichloride solution to an evaporator, heating it to 100° C. for concentration, and concentrating it until solidified, and the obtained solid substance is high-purity iridium trichloride.

[0046] Comparative Example 1: A method for preparing iridium trichloride comprises the following steps: Step 1, mixing 3kg of ammonium chloroiridate and 9L of aqua regia, heating to 95°C for reaction for 3.5h and then cooling to obtain liquid A, wherein the volume ratio of hydrochloric acid to nitric acid in the aqua regia is 3:1; the mass fraction of hydrochloric acid used in the preparation of the aqua regia is 36%, and the mass fraction of nitric acid is 65%.

[0047] Step 2, transfer the liquid A obtained in step 1 to an evaporator, set the heating temperature to 100°C for ammonium chloroiridate for concentration, and when a large amount of yellow smoke is observed in the condensation column, add 2.25L of hydrochloric acid, continue heating and rotary evaporation to remove the nitrate, until no yellow smoke is generated, and then continue to concentrate to remove excess hydrochloric acid. After completion, stop concentrating and naturally cool for 1h to obtain the nitrate-removing liquid.

[0048] Step 3, transferring the nitrate-removing solution obtained in step 2 to a PP filter for filtering to remove insoluble impurities in the nitrate-removing solution to obtain a chloroiridic acid solution.

[0049] Step 4, testing the metal content of the chloroiridic acid solution, and adjusting the iridium ion content in the solution to 35% according to the test result.

[0050] Step 5, mixing 4 kg of the chloroiridic acid solution prepared in step 3, 4 L of water and 0.6 L of anhydrous ethanol, heating to 110° C., reacting for 10 min and then cooling to obtain liquid B.

[0051] Step 6, transferring the liquid B obtained in step 5 to an evaporator, heating it to 100° C. for concentration, and concentrating it until solidified to obtain a solid substance, namely iridium trichloride.

[0052] Comparative Example 2: A method for preparing iridium trichloride comprises the following steps: Step 1, add 100g of chloroiridic acid, 2g of propanol as a reducing agent, 1.5g of hydrazine hydrochloride and 6.5g of ascorbic acid into a three-necked flask placed in a constant temperature water bath, control the temperature in the constant temperature water bath at 85°C, turn on the magnetic stirring system, perform constant temperature stirring, and reduce at constant temperature for 3h to obtain solution A; Step 2, concentrating solution A and distilling off excess water to obtain a concentrated solution, wherein the concentration of iridium trichloride in the concentrated solution is 2 mol / L; Step 3, placing the concentrated solution in a crystallization dish, and crystallizing at 90° C. for 2 hours, and the obtained solid substance is iridium trichloride.

[0053] Comparative Example 3: A method for preparing iridium trichloride comprises the following steps: Step 1, 1kg iridium powder, 1kg sodium peroxide, 3kg sodium hydroxide and 1kg sodium carbonate are mixed evenly and put into an iron crucible, and melted at 610°C for 3 hours. After cooling, the solid substance in the iron crucible is molten salt.

[0054] Step 2, slowly dissolve the molten salt with 1L of 10% dilute hydrochloric acid, control the pH of the reaction system to be less than 1, then add 2L of aqua regia (the volume ratio of hydrochloric acid and nitric acid in the aqua regia is 3:1; the mass fraction of hydrochloric acid used in the preparation of aqua regia is 36%, and the mass fraction of nitric acid is 65%), boil, filter out insoluble residues, add 1.02kg of ammonium chloride to the obtained filtrate, control the mass fraction of ammonium chloride in the filtrate to be 17%, boil, and filter to obtain a black solid, which is ammonium chloroiridate.

[0055] Step 3, adding 2.13 kg of hydrazine hydrochloride to the ammonium chloroiridate obtained above, heating and stirring to slowly dissolve the solid, and filtering again to obtain an ammonium chloroiridate solution.

[0056] Step 4, adding 12g of sodium sulfide solution to the ammonium chloroiridate solution, then boiling for 2h, standing, cooling, and filtering to obtain a pure ammonium chloroiridate solution; then adding 300g of hydrochloric acid, 300g of hydrogen peroxide, and 1700g of ammonium chloride and boiling for 2h, and successively cooling and filtering to obtain a pure ammonium chloroiridate solid.

[0057] Step 5, add 2L of deionized water and 2L of aqua regia (with the same composition as the aqua regia used in step 2) to the ammonium chloroiridate solid obtained in step 4, boil, dissolve to obtain chloroiridic (IV) acid, adjust pH to 1.5, add 20g of triethylenetetramine, add 2600g of sodium nitrite, boil and filter to obtain a solid of potassium hexanitrosoiridate.

[0058] Step 6: Add 4000 ml of 36% hydrochloric acid to potassium hexanitroiridate and boil the mixture to dissolve high-purity chloroiridic acid (IV), add 2.13 kg of hydrazine hydrochloride, and boil and reduce the mixture to obtain a chloroiridic acid solution (III).

[0059] Step 7, the chloroiridium (III) acid solution is first subjected to rotary evaporation at a rotary evaporation temperature of 75° C. to obtain a thick solid, which is then vacuum filtered and heated at a high temperature of 180° C. for 2 h to obtain a solid substance, namely iridium trichloride.

[0060] Embodiment 2: A method for preparing iridium trichloride comprises the following steps: Step 1, mixing 3kg of ammonium chloroiridate and 12L of aqua regia, heating to 95°C for reaction for 3.5h and then cooling to obtain liquid A, wherein the volume ratio of hydrochloric acid to nitric acid in the aqua regia is 3:1; the mass fraction of hydrochloric acid used in the preparation of the aqua regia is 36%, and the mass fraction of nitric acid is 65%.

[0061] Step 2, transfer the liquid A obtained in step 1 to an evaporator, set the heating temperature to 100°C for ammonium chloroiridate for concentration, and when a large amount of yellow smoke is observed in the condensation column, add 3L of hydrochloric acid with a mass fraction of 30%, continue heating and rotary evaporation to drive out the nitrate, until no yellow smoke is generated, and then continue to concentrate to drive out excess hydrochloric acid. When there is no liquid reflux in the condenser and the temperature of the outer wall of the condenser is room temperature, it can be determined that the excess hydrochloric acid has been removed, and then stop concentrating and naturally cool for 1 hour to obtain the nitrate-removing liquid.

[0062] Step 3, transferring the nitrate-removing solution obtained in step 2 to a PP filter for filtering to remove insoluble impurities in the nitrate-removing solution to obtain a chloroiridic acid solution.

[0063] Step 4, testing the metal content of the chloroiridic acid solution, and adjusting the iridium ion content in the solution to 35% according to the test result.

[0064] Step 5, mixing 4 kg of the chloroiridic acid solution prepared in step 3, 4 L of water and 0.8 L of anhydrous ethanol, heating to 105° C. and reacting for 5 min, and then cooling to obtain liquid B.

[0065] Step 6, transfer the liquid B obtained in step 5 to an evaporator, heat to 100°C for concentration, and concentrate until solidified to obtain the product Step 7, mixing the intermediate product obtained in step 6 with 4 L of water, then heating to 100° C., stirring until the intermediate product is completely dissolved in the water, then cooling to 60° C., adding 0.4 L of anhydrous ethanol, mixing evenly, heating to 90° C. and heating for 10 min, then cooling and filtering to obtain an iridium trichloride solution.

[0066] Step 8, transferring the iridium trichloride solution to an evaporator, heating it to 100° C. for concentration, and concentrating it until solidified, and the obtained solid substance is high-purity iridium trichloride.

[0067] Embodiment 3: A method for preparing iridium trichloride comprises the following steps: Step 1, mixing 4 kg of ammonium chloroiridate and 15 L of aqua regia, heating to 100 ° C. for reaction for 3.5 hours and then cooling to obtain liquid A, wherein the volume ratio of hydrochloric acid to nitric acid in the aqua regia is 3:1; the mass fraction of hydrochloric acid used in the preparation of the aqua regia is 36%, and the mass fraction of nitric acid is 65%.

[0068] Step 2, transfer the liquid A obtained in step 1 to an evaporator, set the heating temperature to 100°C for ammonium chloroiridate for concentration, and when a large amount of yellow smoke is observed in the condensation column, add 3.75L of hydrochloric acid with a mass fraction of 36%, continue heating and rotary evaporation to drive out the nitrate, until no yellow smoke is generated, and then continue to concentrate to drive out excess hydrochloric acid. When there is no liquid reflux in the condenser and the temperature of the outer wall of the condenser is room temperature, it can be determined that the excess hydrochloric acid has been removed, and then stop concentrating and naturally cool for 1 hour to obtain the nitrate-removing liquid.

[0069] Step 3, transferring the nitrate-removing solution obtained in step 2 to a PP filter for filtering to remove insoluble impurities in the nitrate-removing solution to obtain a chloroiridic acid solution.

[0070] Step 4, testing the metal content of the chloroiridic acid solution, and adjusting the iridium ion content in the solution to 35% according to the test result.

[0071] Step 5, mixing 4 kg of the chloroiridic acid solution prepared in step 3, 4 L of water and 1 L of anhydrous ethanol, heating to 108° C., reacting for 10 min, and then cooling to obtain liquid B.

[0072] Step 6, transferring the liquid B obtained in step 5 to an evaporator, heating it to 100° C. for concentration, and concentrating it until solidified to obtain an intermediate product.

[0073] Step 7, mixing the intermediate product obtained in step 6 with 4 L of water, then heating to 100° C., stirring until the intermediate product is completely dissolved in the water, then cooling to 60° C., adding 0.5 L of anhydrous ethanol, mixing evenly, heating to 95° C. and heating for 15 min, then cooling and filtering to obtain an iridium trichloride solution.

[0074] Step 8, transferring the iridium trichloride solution to an evaporator, heating it to 100° C. for concentration, and concentrating it until solidified, and the obtained solid substance is high-purity iridium trichloride.

[0075] The purity of iridium trichloride obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was tested, and the test data are shown in Table 1.

[0076] Table 1 Purity of iridium trichloride obtained in Examples 1 to 3 and Comparative Examples 1 to 3 The data provided in Table 1 can prove that the iridium trichloride prepared by the preparation method provided by the present invention has high purity.

[0077] By comparing Example 1 with Comparative Example 1, it can be seen that the step-by-step reduction process provided by the present invention can reduce the formation of by-products, thereby improving the purity and yield of iridium trichloride and improving the utilization rate of raw materials.

[0078] Comparative Examples 2 and 3 are commonly used processes for preparing iridium trichloride in the prior art. The purities of iridium trichloride prepared in Comparative Examples 2 and 3 are 97% and 96%, respectively. The inventors speculate that the reason affecting the purity of Comparative Example 2 may be that hydrazine hydrochloride is used as a reducing agent in Comparative Example 2. Hydrazine hydrochloride is a strong reducing agent. There is a local reaction that is too violent during the reaction process, and by-products are easily generated, thereby reducing the purity of the product.

[0079] The inventors speculate that the reasons affecting the purity of Comparative Example 3 may be: first, hydrazine hydrochloride is also used as a reducing agent in Comparative Example 3, and the reaction is violent and easy to generate by-products; second, an iron crucible is used as a reactor in Comparative Example 3, and a large amount of iron impurities are introduced during the alkali dissolution process. Although sodium sulfide is added to remove iron, the risk of increased impurities is generally increased; third, sodium nitrite is used in Comparative Example 3 to form an iridium nitrite complex, and the structure of the complex is relatively stable. It is difficult to completely remove nitrite by hydrochloric acid, which affects subsequent reduction and increases the source of impurities, thereby affecting the purity of the product.

[0080] The present invention adopts a mild reducing agent and controls the amount of the reducing agent and the reducing conditions, so that the reduction is stable and controllable; in the preparation process, segmented reduction is adopted and the parameters of the segmented reduction are controlled, so that the content of impurities can be further reduced, thereby improving the purity of iridium trichloride.

[0081] Figure 1 The XPS spectrum of iridium trichloride prepared in Example 1 is Figure 1 It can be seen that there is substantially no tetravalent iridium ion in the iridium trichloride prepared in Example 1 of the present invention, which can further prove that the iridium trichloride prepared by the preparation method provided by the present invention has high purity.

[0082] Figure 2 The XPS spectrum of iridium trichloride prepared in Comparative Example 1 is Figure 2 It can be seen that the content of iridium trichloride in the product obtained in Comparative Example 1 is 90%, and the content of iridium tetrachloride and iridium element is 10%, which can further prove that the step-by-step reduction process provided by the present invention can reduce the formation of by-products, thereby improving the purity and yield of iridium trichloride.

[0083] The embodiments described above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing iridium trichloride, characterized in that, The steps include: Step 1, mixing ammonium chloroiridate and aqua regia, heating for reaction and then cooling to obtain liquid A; Step 2, heating liquid A until a large amount of yellow smoke appears, adding hydrochloric acid, and then continuing to heat and rotary evaporate to remove the nitrate until no yellow smoke appears, and then continuing to concentrate until no liquid is recovered in the condenser tube, and then cooling and filtering in sequence to obtain the nitrate-removing liquid; Step 3, mixing the nitrate-removing liquid and anhydrous ethanol, heating for reaction and then cooling to obtain liquid B; Step 4, mixing solution B and anhydrous ethanol, heating for reaction, cooling, and then concentrating and drying to obtain solid particles, namely iridium trichloride.

2. The preparation method of iridium trichloride as claimed in claim 1, characterized in that, In step 1, the solid-to-liquid ratio of ammonium chloroiridate and aqua regia used in preparing liquid A is 1 kg: 3-5 L.

3. The preparation method of iridium trichloride as claimed in claim 1 or 2, characterized in that, In step 1, the reaction temperature is 90-100°C and the reaction time is 3-4h.

4. The preparation method of iridium trichloride as claimed in claim 1, characterized in that, In step 2, the molar ratio of the added hydrochloric acid to the nitrate ions in liquid A is 0.6-0.8:1, the mass fraction of the hydrochloric acid is 30%-36%; and the heating temperature is 100-110°C.

5. The preparation method of iridium trichloride as claimed in claim 1, characterized in that, In step 3, when the nitrate-removing solution and anhydrous ethanol are mixed, the molar ratio of iridium ions in the nitrate-removing solution to anhydrous ethanol is 1:1.38-2.

31.

6. The preparation method of iridium trichloride as claimed in claim 1 or 5, characterized in that, In step 3, the heating temperature is 100-110° C. and the heating time is 5-10 min.

7. The preparation method of iridium trichloride as claimed in claim 1, characterized in that, After step 3 and before step 4, a concentration step is further included, in which liquid B is heated to 100-110° C. and concentrated until solidified.

8. The preparation method of iridium trichloride as claimed in claim 1 or 4, characterized in that, In step 4, when liquid B and anhydrous ethanol are mixed, the molar ratio of iridium ions in liquid B to anhydrous ethanol is 1:0.69-1.

15.

9. The preparation method of iridium trichloride as claimed in claim 1, characterized in that, In step 3, the heating temperature is 90-100° C. and the heating time is 10-15 min.

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