阅读说明：本技术 一种高纯度无水氯化稀土的制备方法 (Preparation method of high-purity anhydrous rare earth chloride ) 是由 冀代明 王新政 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种高纯度无水氯化稀土的制备方法,包括：将高纯度含水碳酸稀土在微负压下加热脱水,得到原料无水碳酸稀土；将步得到的粗无水碳酸稀土放置于回转气氛炉中进行微负压抽吸,并阶梯逐步升温；达到技术要求后,缓慢开启无水氯化氢贮罐,按技术要求给定流量,使无水碳酸稀土在纯无水氯化氢下进行氯化反应；通入理论量的105％～130％无水氯化氢气体,控制反应速率为1kg～20kg/小时通气量,通气结束后,在氮气保护下冷却室温；将反应后的产物利用真空吸料机在干燥氮气保护下吸入贮存容器中进行检验,成品无水氯化稀土均于隔绝水和氧气的条件下进行收集。本发明工艺成本较低,过程控制简单,环保、安全,易于工业化生产。(The invention discloses a preparation method of high-purity anhydrous rare earth chloride, which comprises the following steps: heating and dehydrating high-purity hydrous rare earth carbonate under a micro-negative pressure to obtain anhydrous rare earth carbonate as a raw material; placing the obtained crude anhydrous rare earth carbonate in a rotary atmosphere furnace for micro-negative pressure suction, and gradually heating in a step manner; after the technical requirements are met, slowly starting an anhydrous hydrogen chloride storage tank, and setting the flow rate according to the technical requirements to perform chlorination reaction on anhydrous rare earth carbonate under pure anhydrous hydrogen chloride; introducing 105-130% of theoretical amount of anhydrous hydrogen chloride gas, controlling the reaction rate to be 1-20 kg/hour ventilation, and cooling the reaction product to room temperature under the protection of nitrogen after the ventilation is finished; and sucking the reacted product into a storage container by using a vacuum suction machine under the protection of dry nitrogen for inspection, and collecting the finished anhydrous rare earth chloride under the condition of water and oxygen isolation. The method has the advantages of low process cost, simple process control, environmental protection, safety and easy industrial production.)

1. A preparation method of high-purity anhydrous rare earth chloride is characterized in that,

(1) heating and dehydrating the high-purity aqueous rare earth carbonate with the sigma non-rare earth impurity less than or equal to 100ppm under the micro-negative pressure to obtain the raw material anhydrous rare earth carbonate RE₂(CO₃)₃；

(2) Placing the crude anhydrous rare earth carbonate obtained in the step (1) in a rotary atmosphere furnace for micro-negative pressure suction, and gradually heating to 100-350 ℃ in a stepped manner; specifically, the heating rate is 5 ℃/min, the temperature is raised to 150 ℃ in the first step, and the temperature is kept for 60 minutes; secondly, heating to 200 ℃, and keeping the temperature for 45 minutes; thirdly, heating to 250 ℃, and preserving heat for 60 minutes; fourthly, heating to 300 ℃, and preserving heat for 45 minutes; fifthly, heating to 350 ℃, and preserving heat for 60 minutes to obtain anhydrous rare earth carbonate;

(3) slowly opening an anhydrous hydrogen chloride storage tank for anhydrous rare earth carbonate with the water content less than or equal to 5% in the step (2), and setting the flow according to the technical requirement to perform chlorination reaction on the anhydrous rare earth carbonate under pure anhydrous hydrogen chloride;

(4) introducing 105-130% of theoretical amount of anhydrous hydrogen chloride gas into the reaction kettle in the step (3), controlling the reaction rate to be 1-20 kg/hour of ventilation, and cooling the reaction kettle to room temperature under the protection of nitrogen after the ventilation is finished;

(5) and (4) sucking the product reacted in the step (4) into a storage container for inspection under the protection of dry nitrogen by using a vacuum suction machine, and collecting the obtained finished anhydrous rare earth chloride under the condition of water and oxygen isolation.

2. The method of claim 1, wherein the anhydrous rare earth carbonate RE is₂(CO₃)₃RE in the composition is any one or more than two rare earth elements of Y, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

3. The method for preparing high-purity anhydrous rare earth chloride according to claim 1, wherein carbon dioxide gas generated by the reaction in the step (3) is discharged after being purified by a tail gas recovery device and reaching the standard.

4. The method for preparing high-purity anhydrous rare earth chloride according to claim 1, wherein the conditions of isolating water and oxygen in the step (5) are a system environment in which the content of both water and oxygen is less than 10 ppm.

5. The method for preparing high-purity anhydrous rare earth chloride according to claim 1, wherein the temperature of the step (2) is gradually increased to 220-290 ℃.

6. The method for preparing high-purity anhydrous rare earth chloride according to claim 5, wherein the temperature of the system in the step (2) is gradually raised to 230 ℃, 250 ℃ or 280 ℃.

Technical Field

The invention relates to the technical field of preparation of rare earth compounds, in particular to a preparation method of high-purity anhydrous rare earth chloride.

Background

Anhydrous rare earth chloride is used for preparing high-purity metals, rare earth element organic compounds, medical additives, organic synthesis catalysts, drying agents and the like, and the existing data inquiry shows that all the methods are prepared by adopting methods of mixing hydrous rare earth chloride with ammonium chloride and then carrying out high-temperature vacuum dehydration and the like. The method has the advantages that the carrying amount of other non-rare earth impurities cannot be controlled, only industrial-grade anhydrous rare earth chloride can be produced, the process control is complex, the minimum water content can only be within 2%, the content of rare earth oxychloride is high, the minimum content can only be about 1%, and the requirement of high-purity products cannot be met.

The existing anhydrous rare earth chloride production process takes rare earth chloride as a raw material and ammonium chloride as an auxiliary material to carry out high-temperature vacuum dehydration, the production process has long flow, high energy consumption and material consumption, causes certain energy waste, has complex process control, easily generates oxychloride in the dehydration process, and is very easy to deliquesce a finished product, thereby bringing great difficulties to the preparation, packaging, storage, crystal growth and the like of the anhydrous rare earth chloride. The development of the anhydrous rare earth chloride scintillator industry is seriously hindered due to the high price of the high-purity anhydrous rare earth chloride required by the scintillator.

Disclosure of Invention

The invention aims to provide a preparation method of high-purity anhydrous rare earth chloride, which has the advantages of low cost, easy scale production, simple process control and no introduction of other metal ions.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of high-purity anhydrous rare earth chloride comprises (1) heating and dehydrating sigma non-rare earth impurities less than or equal to 100ppm high-purity aqueous rare earth carbonate under micro-negative pressure to obtain raw material anhydrous rare earth carbonate RE₂(CO₃)₃；

(2) Placing the crude anhydrous rare earth carbonate obtained in the step (1) in a rotary atmosphere furnace (model QFL-300L, purchased from Zibo Zi kiln technology Co., Ltd.) for micro-negative pressure suction, and gradually heating to 100-350 ℃ in a step manner; specifically, the heating rate is 5 ℃/min, the temperature is raised to 150 ℃ in the first step, and the temperature is kept for 60 minutes; secondly, heating to 200 ℃, and keeping the temperature for 45 minutes; thirdly, heating to 250 ℃, and preserving heat for 60 minutes; fourthly, heating to 300 ℃, and preserving heat for 45 minutes; fifthly, heating to 350 ℃, and preserving heat for 60 minutes to obtain anhydrous rare earth carbonate;

(3) after the anhydrous rare earth carbonate with the water content less than or equal to 5% in the step (2) is obtained, slowly opening an anhydrous hydrogen chloride storage tank, and setting the flow according to the technical requirement to perform chlorination reaction on the anhydrous rare earth carbonate under pure anhydrous hydrogen chloride;

(4) introducing 105-130% of theoretical amount of anhydrous hydrogen chloride gas into the reaction kettle in the step (3), controlling the reaction rate to be 1-20 kg/hour of ventilation, and cooling the reaction kettle to room temperature under the protection of nitrogen after the ventilation is finished;

(5) and (4) sucking the product reacted in the step (4) into a storage container for inspection under the protection of dry nitrogen by using a vacuum suction machine, and collecting the obtained finished anhydrous rare earth chloride under the condition of water and oxygen isolation.

Further, the anhydrous rare earth carbonate RE₂(CO₃)₃RE in the composition is any one or more than two rare earth elements of Y, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

Further, the carbon dioxide gas generated in the reaction in the step (3) is purified by a tail gas recovery device and is discharged after reaching the standard.

Further, the condition of isolating water and oxygen in the step (5) is that the content of both water and oxygen is less than 10ppm of the system environment.

Further, the temperature of the step in the step (2) is gradually increased to 220-290 ℃.

Further, the system in the step (2) is gradually heated to 230 ℃, 250 ℃ or 280 ℃.

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

compared with the traditional process, the process disclosed by the invention does not need to carry out multi-step operation, only controls the quality of the raw materials and the auxiliary materials, can produce the high-purity anhydrous rare earth chloride, and meanwhile, the production cost of the process is reduced by 40% compared with that of the traditional production process, so that the process is suitable for large-scale industrial production;

the process has the advantages of less control of technical indexes in the production process, safe production process and no generation of three wastes, and excessive hydrogen chloride can be recycled for secondary recycling by using rare earth carbonate;

the process has low energy consumption and high yield, and the produced finished products are all in a crystal shape, thereby providing high-quality raw materials for subsequent scintillator manufacture and medical use;

compared with the traditional anhydrous rare earth chloride production, the process of the invention does not contain excessive hydrogen chloride gas of other metal ions (such as ammonium chloride and the like), can be completely replaced by dry high-purity nitrogen, and has high product purity;

the preparation method can be carried out under micro negative pressure when the rare earth carbonate is dehydrated, has higher process fault tolerance compared with the traditional process method, has lower requirements on the moisture content and the oxygen content of the primary product anhydrous carbonate, and is suitable for industrialized and large-scale production of anhydrous rare earth chloride.

Drawings

The invention is further illustrated in the following description with reference to the drawings.

FIG. 1 is a process flow diagram of the preparation method of high-purity anhydrous rare earth chloride according to the present invention.

Detailed Description

As shown in figure 1, a preparation method of high-purity anhydrous rare earth chloride, (1) heating and dehydrating sigma non-rare earth impurities less than or equal to 100ppm high-purity aqueous rare earth carbonate under micro-negative pressure to obtain raw material anhydrous rare earth carbonate RE2(CO3) 3;

(2) placing the crude anhydrous rare earth carbonate obtained in the step (1) in a rotary atmosphere furnace (model QFL-300L, purchased from Zibo Zi kiln technology Co., Ltd.) for micro-negative pressure suction, and gradually heating to 100-350 ℃ in a step manner; specifically, the heating rate is 5 ℃/min, the temperature is raised to 150 ℃ in the first step, and the temperature is kept for 60 minutes; secondly, heating to 200 ℃, and keeping the temperature for 45 minutes; thirdly, heating to 250 ℃, and preserving heat for 60 minutes; fourthly, heating to 300 ℃, and preserving heat for 45 minutes; fifthly, heating to 350 ℃, and preserving heat for 60 minutes to obtain anhydrous rare earth carbonate;

(3) after the anhydrous rare earth carbonate with the water content less than or equal to 5% in the step (2) is obtained, slowly opening an anhydrous hydrogen chloride storage tank, and setting the flow according to the technical requirement to perform chlorination reaction on the anhydrous rare earth carbonate under pure anhydrous hydrogen chloride;

(4) introducing 105-130% of theoretical amount of anhydrous hydrogen chloride gas into the reaction kettle in the step (3), controlling the reaction rate to be 1-20 kg/hour of ventilation, and cooling the reaction kettle to room temperature under the protection of nitrogen after the ventilation is finished;

(5) and (4) sucking the product reacted in the step (4) into a storage container for inspection under the protection of dry nitrogen by using a vacuum suction machine, and collecting the obtained finished anhydrous rare earth chloride under the condition of water and oxygen isolation.

The obtained finished anhydrous rare earth chloride is collected under the conditions of water and oxygen isolation, wherein the condition content of the water and the oxygen isolation is less than 10ppm, the requirements can be met in a commercially available circulating glove box and a drying chamber, and in addition, a vacuum packaging system can meet the requirements by adopting high-purity dry nitrogen;

after the steps are carried out, a high-purity anhydrous rare earth chloride product with the water content of less than or equal to 100ppm and the oxygen content of less than or equal to 100ppm can be obtained;

the raw material used by the invention is high-purity rare earth carbonate with sigma non-rare earth impurity less than or equal to 100ppm, and the raw material is a mature high-purity primary raw material product, is widely used in the field of electronic and optical glass and is commercially available. The auxiliary material is pure anhydrous hydrogen chloride which is available on the market.

Example 1:

weighing high-purity lanthanum carbonate with the sigma non-rare earth impurity content of less than or equal to 100ppm and the sigma non-lanthanum rare earth impurity content of less than or equal to 100ppm, and carrying out the following operations under micro-negative pressure: specifically, the heating rate is 5 ℃/min, the temperature is raised to 150 ℃ in the first step, and the temperature is kept for 60 minutes; secondly, heating to 200 ℃, and keeping the temperature for 45 minutes; thirdly, heating to 250 ℃, and preserving heat for 60 minutes; fourthly, heating to 300 ℃, and preserving heat for 45 minutes; fifthly, raising the temperature to 350 ℃, keeping the temperature for 60 minutes, and then introducing 6.7kg of anhydrous hydrogen chloride gas under the condition of dynamic heat preservation, wherein the ventilation rate is 2 kg/h. And after the ventilation is finished, stopping heating, cooling to room temperature under the protection of dry nitrogen, sucking the reactant into a storage tank by using a vacuum sucking machine under the protection of dry nitrogen, and finally analyzing and packaging to obtain 13.48kg of a high-purity lanthanum chloride finished product with sigma non-rare earth impurities less than or equal to 100ppm and sigma non-lanthanum rare earth impurities less than or equal to 100 ppm. Through inspection, the high-purity anhydrous lanthanum chloride of the product of the embodiment has 89ppm of oxygen content, 54ppm of water content and 28 ч m of crystal grain diameter D50.

Example 2:

weighing 50kg of high-purity cerium carbonate with sigma non-rare earth impurities less than or equal to 100ppm and sigma non-cerium rare earth impurities less than or equal to 100ppm, and performing the following operations under micro-negative pressure: specifically, the heating rate is 5 ℃/min, the temperature is raised to 150 ℃ in the first step, and the temperature is kept for 60 minutes; secondly, heating to 200 ℃, and keeping the temperature for 45 minutes; thirdly, heating to 250 ℃, and preserving heat for 60 minutes; fourthly, heating to 300 ℃, and preserving heat for 45 minutes; fifthly, raising the temperature to 350 ℃, keeping the temperature for 60 minutes, and then introducing 16.7kg of anhydrous hydrogen chloride gas under the condition of dynamic heat preservation, wherein the ventilation rate is 5 kg/h. And after the ventilation is finished, stopping heating, cooling to room temperature under the protection of dry nitrogen, sucking the reactants into a storage tank by using a vacuum sucking machine under the protection of dry nitrogen, and finally analyzing and packaging to obtain 33.7kg of high-purity cerium chloride finished products. Through inspection, the sigma non-rare earth impurity of the product is less than or equal to 100ppm, the sigma non-lanthanum rare earth impurity is less than or equal to 100ppm, the oxygen content in the high-purity anhydrous cerium chloride is 61ppm, the water content is 48ppm, and the crystal grain diameter D50 is 26 ч m.

Example 3:

weighing 50kg of high-purity neodymium carbonate with sigma non-rare earth impurities less than or equal to 100ppm and sigma non-neodymium rare earth impurities less than or equal to 100ppm, and performing the following operations under the micro-negative pressure: specifically, the heating rate is 5 ℃/min, the temperature is raised to 150 ℃ in the first step, and the temperature is kept for 60 minutes; secondly, heating to 200 ℃, and keeping the temperature for 45 minutes; thirdly, heating to 250 ℃, and preserving heat for 60 minutes; fourthly, heating to 300 ℃, and preserving heat for 45 minutes; fifthly, raising the temperature to 350 ℃, keeping the temperature for 60 minutes, and then introducing 16kg of anhydrous hydrogen chloride gas under the condition of dynamic heat preservation, wherein the ventilation rate is 5 kg/h. And after the ventilation is finished, stopping heating, cooling to room temperature under the protection of dry nitrogen, sucking the reactant into a storage tank by using a vacuum sucking machine under the protection of dry nitrogen, and finally analyzing and packaging to obtain 33.7kg of a high-purity neodymium chloride finished product, wherein sigma non-rare earth impurities are less than or equal to 100ppm, and sigma non-neodymium rare earth impurities are less than or equal to 100 ppm. Through inspection, the high-purity anhydrous neodymium chloride product of the embodiment has the oxygen content of 91ppm, the water content of 42ppm and the crystal grain diameter D50 of 26 ч m.

Example 4:

weighing 50kg of high-purity yttrium carbonate with sigma non-rare earth impurities less than or equal to 100ppm and sigma non-yttrium rare earth impurities less than or equal to 100ppm, and carrying out the following operations under micro-negative pressure: specifically, the heating rate is 5 ℃/min, the temperature is raised to 150 ℃ in the first step, and the temperature is kept for 60 minutes; secondly, heating to 200 ℃, and keeping the temperature for 45 minutes; thirdly, heating to 250 ℃, and preserving heat for 60 minutes; fourthly, heating to 300 ℃, and preserving heat for 45 minutes; fifthly, raising the temperature to 350 ℃, keeping the temperature for 60 minutes, and then introducing 24kg of anhydrous hydrogen chloride gas under the condition of dynamic heat preservation, wherein the ventilation rate is 5 kg/h. And after the ventilation is finished, stopping heating, cooling to room temperature under the protection of dry nitrogen, sucking the reactants into a storage tank by using a vacuum sucking machine under the protection of dry nitrogen, and finally analyzing and packaging to obtain 38.9kg of high-purity yttrium chloride finished products. The examination shows that the product of the embodiment is high-purity anhydrous cerium chloride with the sigma non-rare earth impurity being less than or equal to 100ppm, the sigma non-yttrium rare earth impurity being less than or equal to 100ppm, the oxygen content being 89ppm, the water content being 43ppm, and the crystal grain diameter D50 being 26 ч m.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.