Rare earth chlorine oxides, their preparation methods and uses

Abstract

This invention discloses a rare earth chloride oxide, its preparation method, and its uses. The preparation method includes the following steps: (1) stirring a mixture composed of rare earth chloride, carbon-containing material, and water, and adding ammonia dropwise to the mixture to control the pH value of the mixture at 6-8, thereby obtaining a carbon-containing material loaded with rare earth chloride; wherein, the carbon-containing material is selected from graphite oxide and / or graphene oxide; in the mixture, the rare earth chloride is 20-40 parts by weight, the carbon-containing material is 2-10 parts by weight, and the water is 55-100 parts by weight; (2) calcining the carbon-containing material loaded with rare earth chloride and the rare earth chloride in a weight ratio of 1:(0.6-1.5) in an oxide crucible at 300-700°C for 0.5-10 hours to obtain a calcined product; (3) washing and drying the calcined product to obtain rare earth chloride oxide. The rare earth chloride oxide obtained by this preparation method is a crystalline material in the form of disc-shaped particles.

Description

Technical Field

[0001] This invention relates to a rare earth chlorine oxide, its preparation method, and its uses. Background Technology

[0002] Rare earth chlorides belong to the tetragonal crystal system and possess high chemical stability. They are insoluble in water, non-toxic, and exhibit high light absorption and energy transfer efficiency, making them an important luminescent matrix. Currently, the main methods for preparing rare earth chlorides include solid-state methods, precipitation methods, liquid-phase-high-temperature calcination methods, precursor pyrolysis methods, hydrothermal and solvothermal methods, and sol-gel methods.

[0003] CN110467214A discloses a method for preparing amorphous, fumigant-like two-dimensional samarium oxychloride nanosheets. First, tris(hydroxymethyl)aminomethane and hydrochloric acid are mixed to obtain a buffer solution. Then, a soluble samarium source and graphene oxide are added, and the mixture is ultrasonically treated to obtain a homogeneous suspension. After reaction, solid-liquid separation and drying are performed to obtain a precursor. The precursor is calcined at 500–600°C to obtain samarium oxychloride. This method yields an amorphous, sheet-like product, which only proves that the product contains samarium, oxygen, and chlorine, but cannot confirm that these elements form rare earth chloride oxides. Furthermore, this method yields a sheet-like product. Summary of the Invention

[0004] In view of this, one object of the present invention is to provide a method for preparing rare earth chloride oxides, wherein the rare earth chloride oxides obtained by the method are particulate crystalline substances. Further, the rare earth chloride oxides obtained by this method have small particle sizes. Another object of the present invention is to provide a rare earth chloride oxide. A further object of the present invention is to provide uses for the above-mentioned rare earth chloride oxides.

[0005] The above objectives are achieved through the following technical solutions.

[0006] On one hand, the present invention provides a method for preparing rare earth chlorine oxides, comprising the following steps:

[0007] (1) Stir the mixture of rare earth chloride, carbon-containing material and water, and add ammonia water dropwise to the mixture to control the pH value of the mixture at 6-8, so as to obtain carbon-containing material loaded with rare earth chloride.

[0008] The carbon-containing material is selected from graphite oxide and / or graphene oxide; in the mixture, rare earth chloride is 20-40 parts by weight, carbon-containing material is 2-10 parts by weight, and water is 55-100 parts by weight.

[0009] (2) Carbonaceous material loaded with rare earth chloride and rare earth chloride in a weight ratio of 1:(0.6~1.5) are calcined in an oxide crucible at 300~700℃ for 0.5~10h to obtain the calcined product;

[0010] Wherein, the carbonaceous material loaded with rare earth chloride and the particle size of the rare earth chloride are below 200 mesh;

[0011] (3) The calcined product is washed and dried to obtain rare earth chloride oxides.

[0012] According to the preparation method of the present invention, preferably, the rare earth elements used in the rare earth chlorides in steps (1) and (2) are the same.

[0013] According to the preparation method of the present invention, preferably, the rare earth chloride is lanthanum chloride or gadolinium chloride.

[0014] According to the preparation method of the present invention, preferably, the stirring temperature is 20-99°C and the stirring time is 30-360 min.

[0015] According to the preparation method of the present invention, preferably, the oxide crucible is selected from alumina crucible, silicon oxide crucible, calcium oxide crucible or zirconium oxide crucible.

[0016] According to the preparation method of the present invention, preferably, the washing in step (3) includes the following steps: placing the calcined product in water and ultrasonically washing for 30 min to 120 min, then filtering to obtain a filter cake; rinsing the filter cake with water.

[0017] According to the preparation method of the present invention, preferably, step (2) is carried out in a muffle furnace.

[0018] On the other hand, the present invention provides a rare earth chloride obtained by the above preparation method.

[0019] According to the rare earth chloride of the present invention, preferably, the rare earth chloride is in particulate form, the rare earth chloride is in crystal form, and the particle size of the rare earth chloride is ≤200nm.

[0020] In another aspect, the present invention provides the use of the above-mentioned rare earth chlorides as fluorescent and / or luminescent materials.

[0021] The preparation method of this invention can obtain particulate crystalline rare earth chloride oxides with high purity and small particle size. The rare earth chloride oxides prepared by this method can be used as fluorescent and luminescent materials. Attached Figure Description

[0022] Figure 1 The image shows the X-ray diffraction pattern of the rare earth chloride oxides obtained in Example 1.

[0023] Figure 2 This is a particle size distribution diagram of the rare earth chlorine oxides obtained in Example 1.

[0024] Figure 3 This is a microscopic morphology diagram of the rare earth chloride oxides obtained in Example 1. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0026] <Preparation methods of rare earth chlorine oxides>

[0027] The method for preparing rare earth chlorine oxides of the present invention includes the following steps: (1) a loading step; (2) a calcination step; and (3) a washing and drying step.

[0028] Loading steps

[0029] A mixture of rare earth chlorides, carbonaceous material, and water is stirred, and ammonia is added dropwise to maintain the pH of the mixture at 6–8, yielding a carbonaceous material loaded with rare earth chlorides. This carbonaceous material can then be added to an aqueous solution of rare earth chlorides to obtain a final mixture.

[0030] The mixture of the present invention consists of rare earth chlorides, carbonaceous substances, and water. No other substances are added to the mixture, which avoids the use of irritating chemicals and facilitates the formation of particulate crystalline rare earth chloride oxides.

[0031] In the mixture of the present invention, the content of rare earth chloride is 20 to 40 parts by weight; preferably 25 to 35 parts by weight. In some embodiments, the content of rare earth chloride is 30 to 35 parts by weight. The rare earth chloride may be selected from one or both of lanthanum chloride and gadolinium chloride. The rare earth chloride may be used in the form of a hydrate or in the form of anhydrous rare earth chloride. The above amounts are based on anhydrous rare earth chloride.

[0032] In the mixture of the present invention, the carbon-containing material is selected from graphite oxide and / or graphene oxide. In some embodiments, the carbon-containing material is graphene oxide. The content of the carbon-containing material is 2 to 10 parts by weight; preferably 3 to 8 parts by weight; more preferably 3.5 to 5 parts by weight.

[0033] In the mixture of the present invention, the water content is 55 to 100 parts by weight; preferably 60 to 90 parts by weight; more preferably 65 to 75 parts by weight.

[0034] Controlling the content of substances in the mixture within the above-mentioned range is beneficial for uniformly loading rare earth chlorides onto carbonaceous materials. Using the resulting loaded material as a precursor is advantageous for obtaining crystalline, particulate rare earth chloride oxides.

[0035] The concentration of ammonia water can be 5–20 wt%. In some embodiments, the concentration of ammonia water is 10–15 wt%.

[0036] The stirring temperature can be 20–99°C; preferably 65–95°C; more preferably 80–90°C.

[0037] The stirring time can be 30 to 360 minutes; preferably 100 to 350 minutes; more preferably 240 to 300 minutes.

[0038] Burning steps

[0039] Carbonaceous material loaded with rare earth chlorides and rare earth chlorides in a weight ratio of 1:(0.6–1.5) are calcined in an oxide crucible at 300–700 °C for 0.5–10 h to obtain the calcined product. The rare earth chlorides used in this step are the same as those in the mixture in the previous step. This step can be carried out in a muffle furnace.

[0040] The carbonaceous material loaded with rare earth chlorides has a particle size of less than 200 mesh. In this step, the particle size of the rare earth chlorides is also less than 200 mesh. This particle size can be achieved by grinding.

[0041] The preferred mass ratio of the carbonaceous material loaded with rare earth chloride to the rare earth chloride is 1:(0.8 to 1.2). In some embodiments, the mass ratio of the carbonaceous material loaded with rare earth chloride to the rare earth chloride is 1:(1 to 1.1). This can improve the purity of the rare earth chloride oxide.

[0042] The oxide crucible can be selected from alumina crucibles, silicon oxide crucibles, calcium oxide crucibles, or zirconium oxide crucibles. In some embodiments, the oxide crucible is an alumina crucible.

[0043] The calcination temperature is 300–700°C. In some embodiments, the calcination temperature is 300–400°C. In other embodiments, the calcination temperature is 500–650°C. This helps to fully react the carbonaceous material, improve the purity of the rare earth chloride oxides, and obtain crystalline rare earth chloride oxides. The CO2 gas released during the calcination process can impact the calcination product, refining the particle size of the obtained rare earth chloride oxides.

[0044] The burning time can be 0.5 to 10 hours; preferably 2 to 8 hours; more preferably 4 to 6 hours.

[0045] Washing and drying steps

[0046] The calcined product was washed and dried to obtain rare earth chloride oxides.

[0047] Specifically, washing may include the following steps: ultrasonically washing the calcined product in water, followed by filtration to obtain a filter cake. The filter cake is then rinsed with water. The ultrasonic washing time can be 30–120 minutes. In some embodiments, the ultrasonic washing time is 40–60 minutes. The filter cake can be rinsed with water multiple times, for example, 2–5 times. Water washing can remove rare earth chlorides from the calcined product, improving the purity of the rare earth chloride oxides. The collected washing liquid can be used as a raw material for preparing the mixture.

[0048] It can be dried by baking.

[0049] Rare earth chlorine oxides and their uses

[0050] The rare earth chloride oxides of this invention are crystalline and granular. The rare earth chloride oxides have a disc-like morphology.

[0051] The rare earth chlorine oxides of the present invention have a low particle size. The particle size of the rare earth chlorine oxides is ≤200nm; preferably, the particle size is ≤150nm; more preferably, the particle size is ≤130nm.

[0052] The rare earth chlorine oxides of the present invention have high purity. The purity of the rare earth chlorine oxides is ≥99%; preferably, the purity is ≥99.9%.

[0053] The rare earth chlorine oxides of this invention can be used as fluorescent and / or luminescent materials. The test methods are described below:

[0054] The X-ray diffraction pattern of rare earth chloride oxides was obtained by the following method: rare earth chloride oxides were placed in the groove of a glass stage with a groove, and the rare earth chloride oxides in the groove were flattened with a glass plate. Then, the stage was placed in an X-ray diffractometer and scanned from 10° to 90° at a scanning rate of 4° / min to obtain the X-ray diffraction pattern.

[0055] The particle size distribution of rare earth chloride oxides was obtained by the following method: rare earth chloride oxides were placed in a 500 mL beaker, 450 mL of deionized water was added, and the particle size distribution of rare earth chloride oxides was measured using a laser particle size analyzer.

[0056] The purity of rare earth chlorine oxides was obtained as follows: A certain amount of rare earth chlorine oxides was weighed, dissolved in nitric acid to form a solution, and then the chlorine content in the solution was determined by chemical methods. The mass of the rare earth chlorine oxides was calculated based on the mass of chlorine, and the purity of the rare earth chlorine oxides was obtained by dividing the calculated mass of the rare earth chlorine oxides by the actual sample weight. The oxide crucibles used in the following examples are alumina crucibles.

[0057] Example 1

[0058] 4g of graphene oxide was added to 100g of 30wt% lanthanum chloride solution, and then stirred at 80℃ for 180min. Ammonia solution with a concentration of 10wt% was slowly added dropwise to control the pH of the solution at 6-8, thus obtaining a carbon-containing substance loaded with rare earth chlorides.

[0059] Carbonaceous materials loaded with rare earth chlorides and lanthanum chloride were ground to below 200 mesh.

[0060] The ground carbonaceous material loaded with rare earth chlorides and ground lanthanum chloride were mixed at a mass ratio of 1:1.1 and then placed in an oxide crucible.

[0061] An oxide crucible containing a mixture of carbonaceous material loaded with rare earth chlorides and lanthanum chloride was placed in a muffle furnace and calcined at 300°C for 4.5 h to obtain the calcined product.

[0062] The calcined product was ultrasonically washed in deionized water for 30 minutes, then filtered to obtain a filter cake. The filter cake was rinsed three times with deionized water and then dried to obtain rare earth chloride oxides.

[0063] The purity of the obtained rare earth chlorine oxides was 99.9%.

[0064] Figure 1 This is the X-ray diffraction pattern of the rare earth chloride oxides obtained in Example 1. Figure 1 It can be seen that the rare earth chloride oxide obtained in Example 1 has a LaOCl crystal structure.

[0065] Depend on Figure 2 It can be seen that the diameter of the rare earth chlorine oxide particles obtained in Example 1 is mainly distributed in the range of 10-100 nm.

[0066] Depend on Figure 3 It can be seen that the rare earth chlorine oxide particles obtained in Example 1 have an approximate disc shape.

[0067] Example 2

[0068] 4g of graphite oxide was added to 100g of a 35wt% gadolinium chloride solution, and then stirred at 85℃ for 260min. Ammonia water with a concentration of 10wt% was slowly added dropwise to control the pH of the solution at 6-8, thus obtaining a carbonaceous material loaded with rare earth chlorides.

[0069] Carbonaceous materials loaded with rare earth chlorides and gadolinium chloride were ground to below 200 mesh.

[0070] The ground carbonaceous material loaded with rare earth chlorides and ground gadolinium chloride were mixed at a mass ratio of 1:0.8 and then placed in an oxide crucible.

[0071] An oxide crucible containing a mixture of carbonaceous material loaded with rare earth chlorides and gadolinium chloride was placed in a muffle furnace and calcined at 600°C for 1 hour to obtain the calcined product.

[0072] The calcined product was ultrasonically washed in deionized water for 60 minutes, then filtered to obtain a filter cake. The filter cake was rinsed five times with deionized water and then dried to obtain rare earth chloride oxides.

[0073] The purity of the obtained rare earth chlorine oxides was 99.95%.

[0074] The diameter of the obtained rare earth chlorine oxide particles mainly ranges from 10 to 30 nm.

[0075] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A method for producing a rare earth oxychloride, characterized by, Includes the following steps: 4g of graphene oxide was added to 100g of 30wt% lanthanum chloride solution, and then stirred at 80℃ for 180min. Ammonia solution with a concentration of 10wt% was slowly added dropwise to control the pH value of the solution at 6-8, thus obtaining a carbon-containing substance loaded with rare earth chloride. The carbonaceous material loaded with rare earth chlorides and lanthanum chloride were ground to below 200 mesh. The ground carbonaceous material loaded with rare earth chlorides and ground lanthanum chloride were mixed at a mass ratio of 1:1.1 and then placed in an oxide crucible. An oxide crucible containing a mixture of carbonaceous material loaded with rare earth chlorides and lanthanum chloride was placed in a muffle furnace and calcined at 300°C for 4.5 h to obtain the calcined product. The calcined product was placed in deionized water and ultrasonically washed for 30 minutes, then filtered to obtain a filter cake; the filter cake was rinsed three times with deionized water and then dried to obtain rare earth chloride oxides. The rare earth chloride oxide has a LaOCl crystal structure, a purity of 99.9 wt%, a diameter mainly ranging from 10 to 100 nm, and an approximate disc shape.

Images