A method for preparing high-purity ruthenium powder

Abstract

The present invention discloses a method for preparing high-purity ruthenium powder, which relates to the technical field of high-purity precious metals, and particularly relates to a method for preparing 5N high-purity ruthenium powder using ruthenium trichloride as a raw material, through complex precipitation, impurity removal, calcination, and reduction. The preparation method of the present invention comprises: (1) dissolving ruthenium to prepare a solution: adding ruthenium trichloride to deionized water, then adding concentrated hydrochloric acid, stirring and dissolving, and filtering to obtain a ruthenium solution; (2) adding pyridine to precipitate ruthenium: adding pyridine and hydrogen peroxide to the ruthenium solution and heating to 70-80°C, gradually precipitating a yellow precipitate, and draining the solution after it changes from reddish-brown to light yellow to obtain a ruthenium-containing precipitate; (3) dissolving the ruthenium-containing precipitate to prepare a solution; (4) precipitating ruthenium; (5) calcining; (6) reducing and washing. The preparation method of the present invention can prepare high-purity ruthenium powder. At the same time, since no metal element-containing reagents are added during the preparation process, no toxic or harmful gases are generated during the reaction process, and the production process is stable and highly efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of high-purity noble metal catalysts, and in particular to a method for preparing high-purity ruthenium powder. Background Art

[0002] In the semiconductor ultra-large-scale integrated circuit and magnetic recording fields, high-purity ruthenium powder is produced. Due to its high melting point and high hardness, it is usually used to make ruthenium sputtering targets through powder metallurgy. Ruthenium sputtering targets are used as the coating raw materials for capacitor electrode films of integrated circuits and seed layers of computer hard drives, and extremely stringent performance requirements are placed on the target material purity. For a 0.35μm linewidth process, the chemical purity must be above 99.995%, and for a 0.25μm linewidth process, the chemical purity must be above 99.999%, or even above 99.9999%. Impurities such as alkali metals, transition metal elements, radioactive elements, and gas elements must be very low. Therefore, the impurity content of ruthenium powder must be strictly controlled, and the powder purity is usually required to be greater than 99.999%. Currently, there are many methods for preparing high-purity ruthenium powder. The most commonly used method is to obtain ruthenium hydrochloric acid solution through repeated oxidation distillation absorption, and then obtain ruthenium powder through ammonium chloride precipitation, aging, decomposition and reduction. However, this method has problems such as low powder purity and is not suitable for the production of high-purity ruthenium sputtering targets.

[0003] Japanese companies use a process to produce high-purity ruthenium powder: ruthenium metal is oxidized and dissolved with molten potassium hydroxide and potassium nitrate, converting it into a soluble ruthenate salt. The ruthenium salt is then dissolved and extracted with water. Ruthenium ions are then oxidized and distilled into RuO4 by heating and introducing chlorine gas. The RuO4 is then absorbed in a mixture of dilute hydrochloric acid and ethanol. The solution is dried to obtain solid ruthenium trichloride. This solution is then calcined at high temperature under oxygen flow to convert the ruthenium salt into RuO2. Finally, the ruthenium powder is reduced with hydrogen at high temperature to obtain a ruthenium powder. However, the resulting ruthenium powder contains high levels of impurities such as Na, K, Fe, and Cl.

[0004] CN103223493A discloses a process for preparing high-purity ruthenium powder: crude ruthenium powder is added to a NaOH solution. Under the oxidizing action of chlorine, RuO4 is generated and volatilized. This is then absorbed with hydrochloric acid. The absorption solution is heated and concentrated until it becomes viscous. NaBrO3 is then added to the concentrated solution under acidic conditions. The volatilized RuO4 is also absorbed with hydrochloric acid and concentrated again. This process is repeated three times. The ruthenium absorption solution is concentrated to 30-60 g / L. An oxidant is added to convert Ru(III) into Ru(IV). The solution is heated to 80°C and an excess of NH4Cl is added to precipitate the ruthenium as (NH4)2RuCl6. The solution is filtered, washed, and dried, then calcined and hydrogen-reduced to obtain agglomerated ruthenium particles. After high-energy ball milling, a ruthenium powder with a purity of 99.99% and a morphology and structure that meets the requirements for sputtering targets is obtained. This method suffers from the problem of introducing new impurities during the ball milling process.

[0005] Chinese Patent ZL200810109294.6 discloses a method for producing ammonium hexachlororuthenate and ruthenium powder, as well as ammonium hexachlororuthenate. The ruthenium powder is prepared by calcining the ammonium hexachlororuthenate prepared by adding ammonium chloride to a ruthenium hydrochloric acid solution. The specific steps are: after maintaining the ruthenium hydrochloric acid solution at 80-95°C for at least 3 hours, ammonium chloride is added while stirring in a stirrer at a speed of at least 200 revolutions per minute. The mixture is then stirred at 85-95°C for at least 1 hour to form a precipitate of ammonium hexachlororuthenate. The crystals of ammonium hexachlororuthenate having a moisture content of less than 10% are filtered to obtain the crystals.

[0006] Chinese patent ZL200580006772.5 discloses a method for manufacturing high-purity Ru powder, sputtering targets, thin films, and high-purity Ru powder. The specific steps are to use 99.9% pure Ru raw material as the anode and electrolytically refine it in a solution to obtain 99.99% or more pure ruthenium powder, in which the content of alkali metals such as Na and K is less than 10ppm, and the content of Al is 1 to 50ppm, which is suitable for forming electrode materials for capacitors in semiconductor memory.

[0007] In summary, existing ruthenium powder products have the problems of low purity and high impurity content. Therefore, the preparation of high-purity ruthenium powder is of great significance. Summary of the Invention

[0008] The purpose of the present invention is to address the technical problems of low purity of high-purity ruthenium mentioned above and provide a method for preparing high-purity ruthenium powder without adding any metal element-containing reagents, without generating any toxic or harmful gases during the reaction, and with a stable production process.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A method for preparing high-purity ruthenium powder comprises the following steps:

[0011] (1) Dissolving ruthenium to prepare a solution: Add ruthenium trichloride to deionized water, then add concentrated hydrochloric acid and stir to dissolve, and filter to obtain a ruthenium solution, wherein the ratio of crude ruthenium trichloride, deionized water and concentrated hydrochloric acid is ruthenium trichloride: deionized water: concentrated hydrochloric acid is equal to 100g: 1000ml: 100ml;

[0012] (2) Add pyridine to precipitate ruthenium: Add pyridine and hydrogen peroxide to the ruthenium solution and heat to 70-80°C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, it is drained to obtain a ruthenium-containing precipitate. The amount of pyridine added is 2-3 times the molar amount of ruthenium trichloride, and the mass volume ratio of ruthenium trichloride to hydrogen peroxide is 10 g / mL.

[0013] (3) Dissolving the ruthenium-containing precipitate to prepare a solution: adding the ruthenium-containing precipitate to an ammonia solution for dissolution, and filtering to obtain a ruthenium solution, wherein the concentration of the ammonia solution is 4 mol / L, and the mass volume ratio of ruthenium trichloride to the ammonia solution is 100 g / L;

[0014] (4) Ruthenium precipitation: Add pyridine hydrochloride to the ruthenium solution and stir at room temperature for 4 hours, filter to obtain a ruthenium-containing precipitate, and wash the ruthenium-containing precipitate with deionized water three times;

[0015] (5) Calcination: The ruthenium-containing precipitate is transferred to a crucible and placed in a muffle furnace. The crucible is heated to 220-230°C in an air atmosphere and maintained for 8 hours. The yellow powder is completely decomposed to obtain a brown-black ruthenium-containing powder.

[0016] (6) Reduction and washing: The brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 400-500°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and vacuum dried to obtain high-purity ruthenium powder.

[0017] Furthermore, the ruthenium trichloride in step (1) is a dark red powder with a ruthenium content of 37%.

[0018] Furthermore, the pyridine colorless solution in step (2) has a purity of >99%; and the hydrogen peroxide content is 30%.

[0019] Furthermore, the alkaline aqueous solution in step (3) is ammonia water, and the concentration of the ammonia water solution is 4 mol / L.

[0020] Furthermore, the pyridine hydrochloride in step (4) is a white or off-white crystalline powder with a purity of >99%.

[0021] Furthermore, in step (7), the ruthenium powder is washed 3 times and 6 times with dilute hydrochloric acid and deionized water, respectively.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. No metal-containing reagents are added during the preparation process, no toxic or harmful gases are generated during the reaction, and the production process is stable;

[0024] 2. It can process ruthenium trichloride with high impurity content of iron, calcium, gold, silver, platinum, palladium, rhodium and iridium, and the direct recovery rate of metallic ruthenium reaches more than 96%. The purity of the high-purity ruthenium powder prepared by the present invention is greater than 99.999%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the appearance of the high-purity ruthenium powder prepared by the present invention;

[0026] Figure 2This is the SEM spectrum of the high-purity ruthenium powder prepared in the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to specific embodiments.

[0028] Example 1

[0029] A method for preparing high-purity ruthenium powder comprises the following steps:

[0030] (1) Dissolving ruthenium: Add 100 g of ruthenium trichloride to 1000 ml of deionized water, then add 100 ml of concentrated hydrochloric acid and stir to dissolve. Filter to obtain ruthenium solution A.

[0031] (2) Precipitate ruthenium by adding pyridine: Add 57.89 g of pyridine and 10 ml of hydrogen peroxide to ruthenium solution A and heat to 70°C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, drain it and obtain 175.3 g of ruthenium-containing precipitate B.

[0032] (3) Dissolving and preparing a solution of ruthenium-containing precipitate B: 175.3 g of ruthenium-containing precipitate B was added to 1 L of ammonia solution for dissolution, and filtered to obtain a ruthenium solution C, wherein the concentration of the ammonia solution was 4 mol / L.

[0033] (4) Ruthenium precipitation: Add 400 g of pyridine hydrochloride to the ruthenium solution C, stir at room temperature for 4 hours, and filter to obtain 180.6 g of ruthenium-containing precipitate D. Wash the ruthenium-containing precipitate D with deionized water three times.

[0034] (5) Calcination: 180.6 g of ruthenium-containing precipitate D was transferred to a crucible and placed in a muffle furnace. The crucible was heated to 220 °C in an air atmosphere and maintained for 8 hours. The yellow powder was completely decomposed to obtain 97.6 g of brown-black ruthenium-containing powder E.

[0035] (6) Reduction and washing: 97.6 g of brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 400°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and then vacuum dried to obtain 35.63 g of high-purity ruthenium powder.

[0036] The purity of the high-purity ruthenium powder is greater than 99.999%, and the yield is 96.3%.

[0037] Example 2

[0038] (1) Dissolution of ruthenium: Add 100 g of ruthenium trichloride to 1000 ml of deionized water, then add 100 ml of concentrated hydrochloric acid and stir to dissolve. Filter to obtain ruthenium solution A.

[0039] (2) Precipitate ruthenium by adding pyridine: Add 72.89 g of pyridine and 10 ml of hydrogen peroxide to ruthenium solution A and heat to 76 °C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, drain it and obtain 175.4 g of ruthenium-containing precipitate B.

[0040] (3) Dissolving and preparing a solution of ruthenium-containing precipitate B: 175.4 g of ruthenium-containing precipitate B was added to 1 L of ammonia solution for dissolution, and filtered to obtain ruthenium solution C, wherein the concentration of the ammonia solution was 4 mol / L.

[0041] (4) Ruthenium precipitation: Add 400 g of pyridine hydrochloride to the ruthenium solution C, stir at room temperature for 4 hours, and filter to obtain 180.5 g of ruthenium-containing precipitate D. Wash the ruthenium-containing precipitate D with deionized water three times.

[0042] (5) Calcination: 180.5 g of ruthenium-containing precipitate D was transferred to a crucible and placed in a muffle furnace. The crucible was heated to 227 °C in an air atmosphere and maintained for 8 hours. The yellow powder was completely decomposed to obtain 97.8 g of brown-black ruthenium-containing powder E.

[0043] (6) Reduction and washing: 97.8 g of brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 485°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and then vacuum dried to obtain 35.80 g of high-purity ruthenium powder.

[0044] The purity of the high-purity ruthenium powder is greater than 99.999%, and the yield is 96.7%.

[0045] Example 3

[0046] A method for preparing high-purity ruthenium powder comprises the following steps:

[0047] (1) Dissolution of ruthenium: Add 100 g of ruthenium trichloride to 1000 ml of deionized water, then add 100 ml of concentrated hydrochloric acid and stir to dissolve. Filter to obtain ruthenium solution A.

[0048] (2) Precipitate ruthenium by adding pyridine: Add 76.84 g of pyridine and 10 ml of hydrogen peroxide to ruthenium solution A and heat to 71°C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, drain it and obtain 175.5 g of ruthenium-containing precipitate B.

[0049] (3) Dissolving and preparing a solution of ruthenium-containing precipitate B: 175.5 g of ruthenium-containing precipitate B was added to 1 L of ammonia solution for dissolution, and filtered to obtain ruthenium solution C, wherein the concentration of the ammonia solution was 4 mol / L.

[0050] (4) Ruthenium precipitation: Add 400 g of pyridine hydrochloride to the ruthenium solution C, stir at room temperature for 4 hours, and filter to obtain 180.4 g of ruthenium-containing precipitate D. Wash the ruthenium-containing precipitate D with deionized water three times.

[0051] (5) Calcination: 180.4 g of ruthenium-containing precipitate D was transferred to a crucible and placed in a muffle furnace. The crucible was heated to 230 °C in an air atmosphere and maintained for 8 hours. The yellow powder was completely decomposed to obtain 97.7 g of brown-black ruthenium-containing powder E.

[0052] (6) Reduction and washing: 97.7 g of brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 430°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and then vacuum dried to obtain 35.70 g of high-purity ruthenium powder.

[0053] The purity of the high-purity ruthenium powder is greater than 99.999%, and the yield is 96.5%.

[0054] Example 4

[0055] A method for preparing high-purity ruthenium powder comprises the following steps:

[0056] (1) Dissolution of ruthenium: Add 100 g of ruthenium trichloride to 1000 ml of deionized water, then add 100 ml of concentrated hydrochloric acid and stir to dissolve. Filter to obtain ruthenium solution A.

[0057] (2) Precipitate ruthenium by adding pyridine: Add 80.00 g of pyridine and 10 ml of hydrogen peroxide to ruthenium solution A and heat to 78 °C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, drain it and obtain 175.1 g of ruthenium-containing precipitate B.

[0058] (3) Dissolving and preparing a solution of ruthenium-containing precipitate B: 175.1 g of ruthenium-containing precipitate B was added to 1 L of ammonia solution for dissolution, and filtered to obtain ruthenium solution C, wherein the concentration of the ammonia solution was 4 mol / L.

[0059] (4) Ruthenium precipitation: Add 400 g of pyridine hydrochloride to the ruthenium solution C, stir at room temperature for 4 hours, and filter to obtain 182.2 g of ruthenium-containing precipitate D. Wash the ruthenium-containing precipitate D with deionized water three times.

[0060] (5) Calcination: 182.2 g of ruthenium-containing precipitate D was transferred to a crucible and placed in a muffle furnace. The crucible was heated to 250 °C in an air atmosphere and maintained for 8 hours. The yellow powder was completely decomposed to obtain 97.9 g of brown-black ruthenium-containing powder E.

[0061] (6) Reduction and washing: 97.9 g of brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 490°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and then vacuum dried to obtain 35.74 g of high-purity ruthenium powder.

[0062] The purity of the high-purity ruthenium powder is greater than 99.999%, and the yield is 96.6%.

[0063] Example 5

[0064] A method for preparing high-purity ruthenium powder comprises the following steps:

[0065] (1) Dissolution of ruthenium: Add 100 g of ruthenium trichloride to 1000 ml of deionized water, then add 100 ml of concentrated hydrochloric acid and stir to dissolve. Filter to obtain ruthenium solution A.

[0066] (2) Precipitate ruthenium by adding pyridine: Add 72.00 g of pyridine and 10 ml of hydrogen peroxide to ruthenium solution A and heat to 73 °C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, drain it and obtain 175.6 g of ruthenium-containing precipitate B.

[0067] (3) Dissolving and preparing a solution of ruthenium-containing precipitate B: 175.6 g of ruthenium-containing precipitate B was added to 1 L of ammonia solution for dissolution, and filtered to obtain ruthenium solution C, wherein the concentration of the ammonia solution was 4 mol / L.

[0068] (4) Ruthenium precipitation: Add 400 g of pyridine hydrochloride to the ruthenium solution C, stir at room temperature for 4 hours, and filter to obtain 182.3 g of ruthenium-containing precipitate D. Wash the ruthenium-containing precipitate D with deionized water three times.

[0069] (5) Calcination: 182.3 g of ruthenium-containing precipitate D was transferred to a crucible and placed in a muffle furnace. The crucible was heated to 226 °C in an air atmosphere and maintained for 8 hours. The yellow powder was completely decomposed to obtain 98.1 g of brown-black ruthenium-containing powder E.

[0070] (6) Reduction and washing: 98.1 g of brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 450°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and then vacuum dried to obtain 35.83 g of high-purity ruthenium powder.

[0071] The purity of the high-purity ruthenium powder is greater than 99.999%, and the yield is 96.8%.

[0072] Example 6

[0073] A method for preparing high-purity ruthenium powder comprises the following steps:

[0074] (1) Dissolution of ruthenium: Add 100 g of ruthenium trichloride to 1000 ml of deionized water, then add 100 ml of concentrated hydrochloric acid and stir to dissolve. Filter to obtain ruthenium solution A.

[0075] (2) Precipitation of ruthenium by adding pyridine: Add 80.00 g of pyridine and 10 ml of hydrogen peroxide to ruthenium solution A and heat to 73 °C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, drain it and obtain 175.6 g of ruthenium-containing precipitate B.

[0076] (3) Dissolving and preparing a solution of ruthenium-containing precipitate B: 175.6 g of ruthenium-containing precipitate B was added to 1 L of ammonia solution for dissolution, and filtered to obtain ruthenium solution C, wherein the concentration of the ammonia solution was 4 mol / L.

[0077] (4) Ruthenium precipitation: Add 400 g of pyridine hydrochloride to the ruthenium solution C, stir at room temperature for 4 hours, and filter to obtain 182.2 g of ruthenium-containing precipitate D. Wash the ruthenium-containing precipitate D with deionized water three times.

[0078] (5) Calcination: 182.2 g of ruthenium-containing precipitate D was transferred to a crucible and placed in a muffle furnace. The crucible was heated to 223 °C in an air atmosphere and maintained for 8 hours. The yellow powder was completely decomposed to obtain 97.6 g of brown-black ruthenium-containing powder E.

[0079] (6) Reduction and washing: 97.6 g of brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 430°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and then vacuum dried to obtain 35.80 g of high-purity ruthenium powder.

[0080] The purity of the high-purity ruthenium powder is greater than 99.999%, and the yield is 96.7%.

[0081] Example 7

[0082] A method for preparing high-purity ruthenium powder comprises the following steps:

[0083] (1) Dissolution of ruthenium: Add 100 g of ruthenium trichloride to 1000 ml of deionized water, then add 100 ml of concentrated hydrochloric acid and stir to dissolve. Filter to obtain ruthenium solution A.

[0084] (2) Precipitate ruthenium by adding pyridine: Add 76.06 g of pyridine and 10 ml of hydrogen peroxide to ruthenium solution A and heat to 75°C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, drain it and obtain 175.4 g of ruthenium-containing precipitate B.

[0085] (3) Dissolving and preparing a solution of ruthenium-containing precipitate B: 175.4 g of ruthenium-containing precipitate B was added to 1 L of ammonia solution for dissolution, and filtered to obtain ruthenium solution C, wherein the concentration of the ammonia solution was 4 mol / L.

[0086] (4) Ruthenium precipitation: Add 400 g of pyridine hydrochloride to the ruthenium solution C, stir at room temperature for 4 hours, and filter to obtain 182.0 g of ruthenium-containing precipitate D. Wash the ruthenium-containing precipitate D with deionized water three times.

[0087] (5) Calcination: 182.0 g of ruthenium-containing precipitate D was transferred to a crucible and placed in a muffle furnace. The crucible was heated to 228 °C in an air atmosphere and maintained for 8 hours. The yellow powder was completely decomposed to obtain 97.9 g of brown-black ruthenium-containing powder E.

[0088] (6) Reduction and washing: 97.9 g of brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 430°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and then vacuum dried to obtain 35.81 g of high-purity ruthenium powder.

[0089] The purity of the high-purity ruthenium powder is greater than 99.999%, and the yield is 96.9%.

[0090] Example 8

[0091] A method for preparing high-purity ruthenium powder comprises the following steps:

[0092] (1) Dissolution of ruthenium: Add 100 g of ruthenium trichloride to 1000 ml of deionized water, then add 100 ml of concentrated hydrochloric acid and stir to dissolve. Filter to obtain ruthenium solution A.

[0093] (2) Precipitate ruthenium by adding pyridine: Add 86.84 g of pyridine and 10 ml of hydrogen peroxide to ruthenium solution A and heat to 80°C. A yellow precipitate will gradually precipitate. When the solution changes from reddish brown to light yellow, drain it and obtain 175.5 g of ruthenium-containing precipitate B.

[0094] (3) Dissolving and preparing a solution of ruthenium-containing precipitate B: 175.5 g of ruthenium-containing precipitate B was added to 1 L of ammonia solution for dissolution, and filtered to obtain ruthenium solution C, wherein the concentration of the ammonia solution was 4 mol / L.

[0095] (4) Ruthenium precipitation: Add 400 g of pyridine hydrochloride to the ruthenium solution C, stir at room temperature for 4 hours, and filter to obtain 180.6 g of ruthenium-containing precipitate D. Wash the ruthenium-containing precipitate D with deionized water three times.

[0096] (5) Calcination: 180.6 g of ruthenium-containing precipitate D was transferred to a crucible and placed in a muffle furnace. The crucible was heated to 230 °C in an air atmosphere and maintained for 8 hours. The yellow powder was completely decomposed to obtain 97.8 g of brown-black ruthenium-containing powder E.

[0097] (6) Reduction and washing: 97.8 g of brown-black ruthenium-containing powder E was transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture was introduced at 500°C for 10 hours to obtain ruthenium powder. The obtained ruthenium powder was washed with dilute hydrochloric acid and deionized water, respectively, and then vacuum dried to obtain 35.80 g of high-purity ruthenium powder.

[0098] The purity of the high-purity ruthenium is greater than 99.999%, and the yield is 96.8%.

[0099] The purity analysis of the high-purity ruthenium powder prepared in Example 4 is shown in Table 1.

[0100]

[0101] As can be seen from Table 1, the content of non-metallic elemental impurities such as B and S in the high-purity ruthenium powder prepared by the present invention is very low, and the content of alkali metals such as Li and Cs is also extremely low, indicating that the method disclosed in the present invention is very effective in removing non-metallic impurities and some alkali metals in ruthenium trichloride; among them, K, Na, Fe are widely distributed in nature, and other platinum group metals such as Pd, Rh, Rh, Os have very similar chemical properties to Ru and are extremely difficult to separate, so they must be the focus of attention and research.

[0102] The above descriptions are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing high-purity ruthenium powder, characterized in that: The following steps are involved: (1) Dissolving ruthenium to prepare a solution: Add ruthenium trichloride to deionized water, then add concentrated hydrochloric acid and stir to dissolve, then filter to obtain a ruthenium solution; the dosage ratio of ruthenium trichloride, deionized water and concentrated hydrochloric acid is 100g ruthenium trichloride: deionized water: concentrated hydrochloric acid: 1000ml; (2) Precipitation of ruthenium by adding pyridine: Pyridine and hydrogen peroxide are added to the ruthenium solution and heated to 70-80°C. A yellow precipitate gradually precipitates out. When the solution changes from reddish brown to light yellow, the solution is drained to obtain a ruthenium-containing precipitate. The amount of pyridine added is 2-3 times the molar amount of ruthenium trichloride, and the mass volume ratio of ruthenium trichloride to hydrogen peroxide is 10 g / mL. (3) Dissolving the ruthenium-containing precipitate to prepare a solution: adding the ruthenium-containing precipitate to an ammonia solution for dissolution, and filtering to obtain a ruthenium solution; (4) Ruthenium precipitation: Add pyridine hydrochloride to the ruthenium solution, stir and filter at room temperature to obtain a ruthenium-containing precipitate, and wash the ruthenium-containing precipitate with deionized water; (5) Calcination: The ruthenium-containing precipitate is transferred to a crucible and placed in a muffle furnace. The crucible is heated to 220-230°C in an air atmosphere and maintained for 8 hours. The yellow powder is completely decomposed to obtain a brown-black ruthenium-containing powder. (6) Reduction and washing: The brown-black ruthenium-containing powder is transferred to a crucible and placed in a tube furnace. A nitrogen-hydrogen mixture is introduced at 400-500°C for 10 hours to obtain ruthenium powder; the obtained ruthenium powder is washed with dilute hydrochloric acid and deionized water respectively and vacuum dried to obtain high-purity ruthenium powder.

2. The method for preparing high-purity ruthenium powder according to claim 1, wherein: In step (3), the concentration of the ammonia solution is 4 mol / L, and the mass volume ratio of ruthenium trichloride to the ammonia solution is 100 g / L.

3. The method for preparing high-purity ruthenium powder according to claim 1, wherein: In step (1), ruthenium trichloride is a dark red powder with a ruthenium content of 37%.

4. The method for preparing high-purity ruthenium powder according to claim 1, wherein: The pyridine solution in step (2) is colorless and has a purity of >99%; the hydrogen peroxide content is 30%.

5. The method for preparing high-purity ruthenium powder according to claim 1, wherein: In step (4), pyridine hydrochloride is a white or off-white crystalline powder with a purity of >99%.

6. The method for preparing high-purity ruthenium powder according to claim 1, wherein: In step (6), the ruthenium powder is washed with dilute hydrochloric acid 3 times and deionized water 6 times.

Images