阅读说明：本技术 一种高纯钌粉的制备方法 (Preparation method of high-purity ruthenium powder ) 是由 庞帅 王志 于 2021-07-12 设计创作，主要内容包括：本发明公开了一种高纯钌粉的制备方法,包括以下步骤：(1)氧化蒸馏：以纯度＜99.9%粗钌粉为原料,将其放入三口瓶中,溶解于饱和氢氧化钠溶液内,在碱性条件下通入氯气氧化。本发明在蒸馏后,通过阳离子交换可以除掉阳离子杂质,煅烧工艺时加入尿素作为沉淀引发剂,通过控制合适的条件,使尿素均匀分解释放出氢氧根离子,发生沉淀反应,从而达到控制粒子生长速度、微观形貌、粒度的目的使得钌粉粒度形貌均匀,提升了钌粉质量,并且本发明增设了干燥雾化工艺,使得所得钌粉为球形,进一步提升粒径的均匀度,本钌粉在经过煅烧及氢气还原后,增设了混酸煮洗工艺,通过王水+氢氟酸混合溶液煮洗,使得得到的钌粉振实密度更大,利用率更高。(The invention discloses a preparation method of high-purity ruthenium powder, which comprises the following steps: (1) oxidation and distillation: coarse ruthenium powder with purity less than 99.9% is used as raw material and put into a three-mouth bottle, and the raw material is dissolved in saturated sodium hydroxide solution, and chlorine is introduced for oxidation under alkaline condition. According to the invention, after distillation, cation impurities can be removed through cation exchange, urea is added as a precipitation initiator during a calcination process, and urea is uniformly decomposed to release hydroxide ions through controlling a proper condition to perform a precipitation reaction, so that the purposes of controlling the growth speed, the microstructure and the granularity of the ruthenium powder are achieved, the granularity and the appearance of the ruthenium powder are uniform, and the quality of the ruthenium powder is improved.)

1. A preparation method of high-purity ruthenium powder is characterized by comprising the following steps:

(1) oxidation and distillation: taking coarse ruthenium powder with the purity of less than 99.9 percent as a raw material, putting the raw material into a three-mouth bottle, dissolving the raw material into saturated sodium hydroxide solution, introducing chlorine gas for oxidation under an alkaline condition, and absorbing an oxidation product ruthenium tetroxide by concentrated hydrochloric acid absorption liquid to obtain a chlorine ruthenic acid solution;

(2) purifying and removing impurities: removing impurities from the chlorine ruthenic acid solution obtained in the step (1) by adopting cation exchange resin to obtain pure chlorine ruthenic acid solution;

(3) and (3) precipitation: adjusting the initial pH value of the pure chlorine ruthenic acid solution obtained in the step (2), adding a precipitation initiator, aging, heating and stirring to perform hydrolysis precipitation reaction to generate ammonium chlorine ruthenic acid powder;

(4) drying and atomizing: taking the ammonium chlororuthenate powder obtained in the step (3) as a raw material, adding the raw material into a spray dryer, and reacting to obtain high-purity ammonium chlororuthenate powder;

(5) microwave calcination-hydrogen reduction: calcining the high-purity ammonium chlororuthenate powder obtained in the step (4) in a microwave calcining furnace, and then introducing hydrogen for reduction to obtain spherical metal ruthenium powder;

(6) boiling and washing with mixed acid: and (4) boiling and washing the spherical metal ruthenium powder obtained in the step (5) by adopting a mixed solution of aqua regia and hydrofluoric acid, filtering and separating, fully washing by using deionized water, and then adding the spherical metal ruthenium powder into a vacuum drier for vacuum drying to obtain high-purity ruthenium powder.

2. The method for preparing high purity ruthenium powder according to claim 1, wherein the method comprises the following steps: the temperature of the sodium hydroxide solution in the step (1) is controlled to be 70-90 ℃.

3. The method for preparing high purity ruthenium powder according to claim 1, wherein the method comprises the following steps: and (4) adjusting the initial pH value of the pure chlororuthenic acid solution in the step (3) to 3-5.

4. The method for preparing high purity ruthenium powder according to claim 1, wherein the method comprises the following steps: controlling the liquid flow in the spray dryer in the step (4) to be 3.0-8.0 ml/min, controlling the atomization air pressure to be 0.1-0.5 MPa, controlling the inlet temperature to be 180-220 ℃ and controlling the hot air flow to be 4.0-10.0L/min.

5. The method for preparing high purity ruthenium powder according to claim 1, wherein the method comprises the following steps: the calcining dehydration condition in the step (5): the temperature is 250-350 ℃, and the heat preservation time is 1-2 h.

6. The method for preparing high purity ruthenium powder according to claim 1, wherein the method comprises the following steps: the precipitation initiator in the step (3) is superior pure urea, the molar ratio of ruthenium to urea is 1: 5-8, the aging time is 12-24 hours, the reaction temperature is 80-100 ℃, and the reaction time is 2-4 hours.

Technical Field

The invention relates to the technical field of noble metal powder preparation, in particular to a preparation method of high-purity ruthenium powder.

Background

The rapid development of high and new technologies puts higher demands on the performance of ruthenium (Ru) and Ru-based alloy materials. The preparation of ruthenium powder is the first link in the development of ruthenium industrial technology, and the preparation technology of high-purity spherical ruthenium powder meeting some special purposes still has problems. Pure ruthenium and ruthenium-based alloy materials are widely used as targets in the manufacture of electronic products, and the targets generally require the materials to have low impurity content, uniform structure components and grain sizes and high density.

The Chinese patent with the publication number of CN110919019A discloses a preparation method of high-purity ruthenium powder, which comprises the following steps: (1) introducing chlorine gas to oxidize under an alkaline condition, and oxidizing and distilling; (2) NH4Cl precipitation to obtain ammonium chlororuthenate powder precipitation; (3) carrying out high-pressure hydrothermal reduction to obtain pure ruthenium and ruthenium oxide; (4) hydrogen thermal reduction is carried out to obtain the high-purity micron-level ruthenium powder product. Has the advantages that: the process flow is simple and easy to implement, the purity of the ruthenium powder is more than 99.999%, the free-running property is good, and the particle size is 2-20 mu m. The invention ensures the purity of the ruthenium powder preparation through the processes of oxidative distillation, high-pressure hydrothermal reduction and the like. However, the distilled chlororuthenic acid solution obtained before precipitation easily generates impurities, and meanwhile, the ruthenium powder generated in the calcining reduction process has uneven strength and shape, so that the quality of the final ruthenium powder is influenced.

The Chinese patent with the publication number of CN103223493A discloses a preparation method of high-purity ruthenium powder, which comprises the following steps: dissolving, precipitating, centrifugally filtering, drying, crushing, calcining, reducing and milling. According to the invention, ruthenium in the solution is oxidized into the chlorine ruthenic acid through the oxidation reaction of chlorine, the concentration of ruthenium is controlled to be 45-55 g/L, the concentration of hydrochloric acid is controlled to be 8-12 mol/L, the oxidation temperature is controlled to be 90-100 ℃, the stirring speed is 60-90 r/min, and 99.9% of ammonium ruthenate in the solution can be precipitated under the condition. Realizes the separation of ammonium chlororuthenate and impurities and improves the purity of the ammonium chlororuthenate. However, this method still easily generates impurities in the crushing process, resulting in a decrease in the purity of the finally obtained ruthenium powder.

The publication No. CN1926252A discloses a method for preparing high-purity Ru powder, wherein the contents of alkali metals such as Na and K and the like in the prepared Ru powder are below 10ppm, and the content of Al is 1-50 ppm, the method uses Ru raw materials with the purity below 3N (99.9%) as an anode, and the Ru raw materials are electrolyzed and refined in solution, so that the pure Ru powder with the purity above 4N (99.99%) can be prepared, and the Ru powder is suitable for forming an electrode material for a capacitor of a semiconductor memory. The method is only suitable for electrolytic purification of coarse ruthenium powder, and aims to mainly remove Na, K and Al impurities, the granularity and the morphology of the ruthenium powder cannot be changed, and the granularity and the morphology of the ruthenium powder are not uniform, so that the quality of the ruthenium powder is influenced. The publication No. CN101289229A discloses a method for producing ammonium hexachlororuthenate and ruthenium powder, and ammonium hexachlororuthenate, which aims to reduce the water content to such an extent that there is no problem in the pulverization property when ruthenium powder is produced by firing ammonium hexachlororuthenate prepared by adding ammonium chloride to a hydrochloric acid solution of ruthenium. The present invention provides a method for producing ammonium hexachlororuthenate crystals, which comprises maintaining a hydrochloric acid solution of ruthenium at 80-95 ℃ for 3 hours or more, adding ammonium chloride while stirring at a stirrer revolution of 200 rpm or more, maintaining the solution while stirring at 85-95 ℃ for 1 hour or more, producing a precipitate of ammonium hexachlororuthenate, and filtering the precipitate to obtain ammonium hexachlororuthenate crystals having a water content of 10% or less. The powder prepared by the method has small tap density and can not meet the requirement of target ruthenium powder.

Therefore, we propose a method for preparing high purity ruthenium powder to solve the above problems.

Disclosure of Invention

The invention aims to provide a preparation method of high-purity ruthenium powder, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of high-purity ruthenium powder comprises the following steps:

(1) oxidation and distillation: taking coarse ruthenium powder with the purity of less than 99.9 percent as a raw material, putting the raw material into a three-mouth bottle, dissolving the raw material into saturated sodium hydroxide solution, introducing chlorine gas for oxidation under an alkaline condition, and absorbing an oxidation product ruthenium tetroxide by concentrated hydrochloric acid absorption liquid to obtain a chlorine ruthenic acid solution;

(2) purifying and removing impurities: removing impurities from the chlorine ruthenic acid solution obtained in the step (1) by adopting cation exchange resin to obtain pure chlorine ruthenic acid solution;

(3) and (3) precipitation: adjusting the initial pH value of the chlororuthenic acid solution obtained in the step (2), adding a precipitation initiator, aging, heating and stirring to perform hydrolysis precipitation reaction to generate ammonium chlororuthenate powder;

(4) drying and atomizing: taking the ammonium chlororuthenate powder obtained in the step (3) as a raw material, adding the raw material into a spray dryer, and reacting to obtain high-purity ammonium chlororuthenate powder;

(5) microwave calcination-hydrogen reduction: calcining the high-purity ammonium chlororuthenate powder obtained in the step (4) in a microwave calcining furnace, and then introducing hydrogen for reduction to obtain spherical metal ruthenium powder;

(6) boiling and washing with mixed acid: boiling and washing the spherical metal ruthenium powder obtained in the step (5) by adopting a mixed solution of aqua regia and hydrofluoric acid, filtering and separating, fully washing by using deionized water, and then adding the spherical metal ruthenium powder into a vacuum drier for vacuum drying to obtain high-purity ruthenium powder;

preferably, the temperature of the sodium hydroxide solution in the step (1) is controlled to be 70-90 ℃.

Preferably, the initial pH value of the adjusting solution in the step (3) is 3-5.

Preferably, the flow rate of the control liquid in the spray dryer in the step (4) is 3.0-8.0 ml/min, the atomization air pressure is 0.1-0.5 MPa, the inlet temperature is 180-220 ℃, and the flow rate of the hot air is 4.0-10.0L/min.

Preferably, the calcination dewatering conditions in step (5) are as follows: the temperature is 250-350 ℃, and the heat preservation time is 1-2 h.

Preferably, the precipitation initiator in the step (3) is superior pure urea, the molar ratio of ruthenium to urea is 1: 5-8, the aging time is 12-24 hours, the reaction temperature is 80-100 ℃, and the reaction time is 2-4 hours.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, after distillation, cation impurities can be removed through cation exchange, urea is added as a precipitation initiator during a calcination process, and urea is uniformly decomposed to release hydroxide ions through controlling a proper condition to perform a precipitation reaction, so that the purposes of controlling the growth speed, the microstructure and the granularity of the ruthenium powder are achieved, the granularity and the appearance of the ruthenium powder are uniform, and the quality of the ruthenium powder is improved.

Drawings

FIG. 1 is a schematic diagram of the preparation steps of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the present invention provides a technical solution: a preparation method of high-purity ruthenium powder comprises the following steps:

(1) oxidation and distillation: taking coarse ruthenium powder with the purity of less than 99.9 percent as a raw material, putting the raw material into a three-mouth bottle, dissolving the raw material into a saturated sodium hydroxide solution, controlling the temperature of the sodium hydroxide solution to be 70-90 ℃, introducing chlorine gas to oxidize under an alkaline condition, and absorbing an oxidation product ruthenium tetroxide by using concentrated hydrochloric acid absorption liquid to obtain a chlorine ruthenic acid solution;

(2) purifying and removing impurities: removing impurities from the chlorine ruthenic acid solution obtained in the step (1) by adopting cation exchange resin to obtain pure chlorine ruthenic acid solution;

(3) and (3) precipitation: adjusting the initial pH value of the chlororuthenic acid solution obtained in the step (2), adjusting the initial pH value to 3-5, adding superior pure urea as a precipitation initiator according to the molar ratio of ruthenium to urea of 1:8, aging for 24h, heating the solution to 90 ℃, stirring at constant temperature for reacting for 4h, and performing hydrolysis precipitation reaction to generate ammonium chlororuthenate powder;

(4) drying and atomizing: adding the ammonium chlororuthenate powder obtained in the step (3) as a raw material into a spray dryer, controlling the liquid flow in the spray dryer to be 3.0-8.0 ml/min, the atomization air pressure to be 0.1-0.5 MPa, the inlet temperature to be 180-220 ℃, and the hot air flow to be 4.0-10.0L/min, and reacting to obtain high-purity ammonium chlororuthenate powder;

(5) microwave calcination-hydrogen reduction: calcining the high-purity ammonium chlororuthenate powder obtained in the step (4) in a microwave calcining furnace, adjusting the calcining temperature to be 250-350 ℃, keeping the temperature for 1-2 hours, and introducing hydrogen for reduction to obtain spherical metal ruthenium powder;

(6) boiling and washing with mixed acid: boiling and washing the spherical metal ruthenium powder obtained in the step (5) by adopting a mixed solution of aqua regia and hydrofluoric acid, filtering and separating, fully washing by using deionized water, and then adding the spherical metal ruthenium powder into a vacuum drier for vacuum drying to obtain high-purity ruthenium powder;

the working principle is as follows: the method comprises the steps of taking coarse ruthenium powder with the purity of less than 99.9% as a raw material, putting the raw material into a three-mouth bottle, dissolving the raw material into a saturated sodium hydroxide solution, controlling the temperature of the sodium hydroxide solution to be 70-90 ℃, introducing chlorine gas for oxidation under an alkaline condition, absorbing an oxidation product ruthenium tetroxide with a concentrated hydrochloric acid absorption solution to obtain a chlorine ruthenic acid solution, removing impurities from the obtained chlorine ruthenic acid solution by adopting cation exchange resin to obtain a pure chlorine ruthenic acid solution, adjusting the initial pH value of the obtained chlorine ruthenic acid solution to be 3-5, adding superior pure urea as a precipitation initiator according to the molar ratio of ruthenium to urea of 1:8, aging for 24 hours, heating the solution to 90 ℃, stirring at a constant temperature for reaction for 4 hours to generate hydrolysis precipitation reaction to generate ammonium chlorine ruthenic acid powder, adding the ammonium chloride powder as the raw material into a spray dryer, controlling the flow of the liquid in the spray dryer to be 3.0-8.0 ml/min, atomizing at 0.1-0.5 MPa, introducing at 180-220 ℃, and controlling the flow of hot air at 4.0-10.0L/min, reacting to obtain high-purity ammonium chlororuthenate powder, calcining the high-purity ammonium chlororuthenate powder in a microwave calcining furnace, adjusting the calcining temperature to 250-350 ℃, keeping the temperature for 1-2 h, introducing hydrogen to reduce the powder to obtain spherical metal ruthenium powder, boiling and washing the spherical metal ruthenium powder with a mixed solution of aqua regia and hydrofluoric acid, filtering and separating the solution, fully washing the powder with deionized water, and then adding the powder into a vacuum dryer to carry out vacuum drying to obtain the high-purity ruthenium powder. According to the invention, after distillation, cation impurities can be removed through cation exchange, urea is added as a precipitation initiator during a calcination process, and urea is uniformly decomposed to release hydroxide ions through controlling a proper condition to perform a precipitation reaction, so that the purposes of controlling the growth speed, the microstructure and the granularity of the ruthenium powder are achieved, the granularity and the appearance of the ruthenium powder are uniform, and the quality of the ruthenium powder is improved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.