A method for preparing ytterbium oxide for target material

Abstract

The present invention relates to a method for preparing ytterbium oxide for target materials, and belongs to the technical field of hydrometallurgy and material preparation. Ytterbium chloride liquid with a relative purity of rare earth greater than or equal to 99.99% is used as a raw material, and a refined oxalic acid solution is added thereto for precipitation reaction. During the precipitation reaction, a complexing agent is added to the precipitation slurry, and the precipitation is continued to be complete to obtain ytterbium oxalate. After washing, dehydration, and calcination, ytterbium oxide for target materials is obtained; the complexing agent is a composition of salicylic acid and acetylacetone. The method of the present invention is simple and easy to control, and the transition elements Fe, Cr, Cu, and Ni in the obtained ytterbium oxide product can reach a relatively low level. The transition elements Fe, Cr, Cu, and Ni content are detected by GD-MS, etc., and Fe≤0.06ug / g, Cr<0.05ug / g, Cu<0.05ug / g, and Ni<0.05ug / g are suitable for high-end materials such as metal targets.

Description

Technical Field

[0001] The invention relates to a method for preparing ytterbium oxide for target material, belonging to the technical field of hydrometallurgy and material preparation. Background Art

[0002] Target material is one of the main materials for preparing thin films. High-speed energetic particles are used to bombard the target material, interact with different lasers (ion beams) and different targets, and obtain different film systems to achieve conduction and barrier functions. There are many types of target materials, including metals, alloys, oxides, etc. Rare earth metals are also often used to prepare metal targets. Metal ytterbium targets are usually used as laser materials and portable X-ray sources. Yb ions are important sensitizers for luminescent materials and can also be used for medical diagnosis.

[0003] In the preparation process of ytterbium metal targets, there are high requirements for the purity of the raw material ytterbium metal. By increasing the purity of ytterbium metal from 99.95% to 99.99%, the utilization rate of the ytterbium target material can be significantly increased from 40% to more than 70%, and the production cost can be greatly reduced. Regarding the preparation of ytterbium metal, since Dahn et al. used lanthanum to reduce samarium oxide and ytterbium oxide to obtain samarium and ytterbium metals in 1953, the oxide reduction method has become the mainstream method for the preparation of ytterbium metal for the preparation of high vapor pressure metals. With the widespread application of optoelectronic functional materials such as ytterbium targets, the requirements for the control of impurities in ytterbium metal are getting higher and higher, such as alkali metal elements Na, K, Li, alkaline earth metals Ca, Sr, Ba, and transition elements Fe, Cr, Cu, Ni, etc. There are strict control requirements. In the process of distilling ytterbium metal, the content of alkali metals and alkaline earth metals can be controlled within the required range, and it also has a significant effect on the removal of transition elements. However, due to the presence of transition elements, it is easy to cause an increase in the leakage current of the application material and a decrease in the withstand voltage, which affects the application quality of the ytterbium target. Therefore, the control of the content of transition elements in metal ytterbium is more stringent. At present, the research on metal ytterbium for ytterbium targets is mainly focused on the excess coefficient of reducing agent, block density, heating temperature and insulation time. There is a lack of research on the control of impurities in the raw material ytterbium oxide. The quality of ytterbium oxide products produced in my country is unstable, and the content of transition elements Fe, Cr, Cu, and Ni is often high, which affects the preparation quality of metal ytterbium for ytterbium targets. Therefore, strengthening the research on the preparation process of ytterbium oxide and obtaining a preparation method that satisfies ytterbium oxide for target materials is of great significance to promote its application and give full play to my country's rare earth resource advantages.

[0004] The preparation method of rare earth oxides generally adopts the oxalic acid precipitation method, in which oxalic acid is added to the rare earth chloride solution to precipitate rare earth oxalate, and then washed with pure water, dehydrated and calcined to obtain rare earth oxides. Due to the co-precipitation and inclusion of other small amounts of non-rare earth impurity ions during the precipitation process, the non-rare earth impurity requirements of rare earth oxides are seriously affected, so it is usually considered to remove impurities during the rare earth separation or precipitation process. For the purification process of rare earth separation, solvent extraction and ion exchange are mainly used on an industrial scale, but the purity of ytterbium oxide produced by traditional separation and purification methods is still relatively low. In existing reports, patents ZL202211371027.2, ZL201610334212.2 and ZL201910688473.8 all report the use of solvent extraction or ion exchange to prepare high-purity ytterbium oxide, but the method steps are lengthy, the consumption of chemical reagents is large, and it is difficult to apply to large-scale industrial production. On the other hand, regarding the purification process of rare earth liquid precipitation, in existing reports, Patent ZL201910734227.1 uses a composite precipitant to prepare rare earth oxide, first adding seed crystals, then adding rare earth chloride liquid and sodium bicarbonate / sodium carbonate composite precipitant solution for precipitation reaction, and then aging, liquid-solid separation, washing and calcination in sequence. By controlling the reaction parameters in the process, the indicators of the rare earth oxide obtained after calcination are better than the national standards. In these reports, although different methods can reduce the content of impurities in rare earth oxides, the removal is not thorough enough. Among them, the removal of transition elements Fe, Cr, Cu, and Ni in ytterbium oxide that affect the application of high-performance materials such as target materials is not targeted, and the obtained ytterbium oxide is still difficult to be used in high-end fields such as target materials.

[0005] In summary, how to provide a preparation method for low-transition element ytterbium oxide to meet the application needs of ytterbium oxide in high-end material fields such as sputtering targets is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The main purpose of the present invention is to provide a method for preparing ytterbium oxide for target material, which can significantly reduce the content of transition elements Fe, Cr, Cu and Ni in the ytterbium oxide product to meet the application of high-end fields such as sputtering target material.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for preparing ytterbium oxide for a target material comprises the following steps: adding a refined oxalic acid solution to an ytterbium chloride solution for a precipitation reaction, adding a complexing agent to the precipitation slurry during the precipitation reaction, continuing the precipitation to be complete, obtaining ytterbium oxalate, and washing, dehydrating and calcining to obtain ytterbium oxide for a target material; the complexing agent is a combination of salicylic acid and acetylacetone.

[0009] Preferably, the complexing agent is added during the precipitation reaction when the refined oxalic acid solution is added to 80-95% of the total oxalic acid consumption.

[0010] More preferably, the complexing agent is added during the precipitation reaction when the refined oxalic acid solution is added to 85-90% of the total oxalic acid consumption.

[0011] Preferably, the added mass of the complexing agent is 1-10% of the amount of rare earth REO in the ytterbium chloride reaction solution.

[0012] More preferably, the added mass of the complexing agent is 2-5% of the amount of rare earth REO in the ytterbium chloride reaction solution.

[0013] Preferably, the mass ratio of salicylic acid in the complexing agent to the composition is 60-90%.

[0014] More preferably, the mass ratio of salicylic acid in the complexing agent to the composition is 70-80%.

[0015] Preferably, the relative purity of the ytterbium chloride solution is Yb2O3 / REO≥99.99%.

[0016] Preferably, the rare earth ion concentration of the ytterbium chloride solution is 0.2-1.0 mol / L.

[0017] Preferably, the concentration of the refined oxalic acid solution is 80-150 g / L, and the mass ratio of oxalic acid to the desired precipitated REO is (1.1-1.25):1.

[0018] Transition elements Fe, Cr, Cu, and Ni are mainly introduced by ytterbium chloride solution and precipitant oxalic acid. In the industrial production of rare earth ytterbium oxide, ytterbium chloride solution generally needs to be subjected to an extraction process to remove impurity elements that affect the quality of rare earth ytterbium oxide, and the obtained ytterbium chloride solution still contains a small amount of transition element impurities. During the precipitation process, these impurities are easily accompanied by the addition of precipitant oxalic acid, and are physically or chemically wrapped and adsorbed in ytterbium oxalate, thereby affecting the quality of the final product ytterbium oxide. The present invention achieves the removal of transition elements Fe, Cr, Cu, and Ni by adding a complexing agent during the precipitation process. The selected complexing agent is an organic complexing agent. Salicylic acid can produce a good complexing effect with ions of transition elements Fe, Cr, Cu, and Ni, and the complex is easily soluble in water. The coordination stability of the complex is significantly greater than the coordination stability of the complex formed by oxalic acid and the above ions. For example, salicylic acid, acetylacetone, oxalic acid and Fe 3+The complex stability constants lgK are 16.48, 11.4, and 9.4 respectively; at the same time, acetylacetone can promote the complex competition between salicylic acid and oxalic acid, ensuring that the above impurity ions do not form complexes with oxalic acid. The solubility product constant of ytterbium oxalate is very small, so controlling the amount of complexing agent has no effect on the precipitation of ytterbium oxalate, so that the impurity ions of Fe, Cr, Cu, and Ni elements can be removed relatively well. When the refined oxalic acid is added to 80%-95% of the total oxalic acid consumption, the rare earth ions are basically completely combined with oxalic acid. At this time, the complexing agent is added to preferentially combine with the above four ions to form a stable water-soluble complex, thereby ensuring that the impurity ions exist in the solution and are removed by solid-liquid separation and washing. Excess organic matter is completely decomposed during the high-temperature burning process without affecting the purity of the product.

[0019] The method of the present invention is simple and easy to control, and the transition elements Fe, Cr, Cu, and Ni in the obtained ytterbium oxide product can reach a relatively low level. The ytterbium oxide prepared by the present invention is tested for the transition elements Fe, Cr, Cu, and Ni content by GD-MS, etc., and Fe≤0.06ug / g, Cr<0.05ug / g, Cu<0.05ug / g, and Ni<0.05ug / g, and is suitable for high-end materials such as ytterbium oxide for metal targets. DETAILED DESCRIPTION

[0020] In order to describe the present invention more clearly, the present invention is further described in detail below through examples.

[0021] A method for preparing ytterbium oxide for target materials comprises adding a refined oxalic acid solution to an ytterbium chloride liquid having a relative purity of rare earth greater than or equal to 99.99% for precipitation reaction, adding a complexing agent to the precipitation slurry during the precipitation reaction to obtain ytterbium oxalate, and washing, dehydrating, and calcining to obtain ytterbium oxide; the complexing agent is a combination of salicylic acid and acetylacetone. The ytterbium oxide product finally obtained has Fe≤0.06ug / g, Cr<0.05ug / g, Cu<0.05ug / g, and Ni<0.05ug / g, and is suitable for high-end materials such as metal targets.

[0022] Example 1

[0023] Take 10L of ytterbium chloride solution with a rare earth ion concentration of 0.2mol / L (relative purity of rare earth 99.99%, Fe=16ug / ml, Cr=0.06ug / ml, Cu=0.10ug / ml, Ni<0.05ug / ml), take 433.4g of refined oxalic acid to prepare 2.89L of refined oxalic acid solution with a concentration of 150g / L; add the refined oxalic acid solution to the ytterbium chloride solution under stirring for precipitation reaction, when the oxalic acid solution is added to 2.74L, add 3.94g of a complexing agent with a mass ratio of salicylic acid 60%+acetylacetone 40%, continue stirring, and then add the remaining oxalic acid solution 0.15L to obtain ytterbium oxalate slurry; filter, wash the precipitate until the wash water is neutral, dehydrate, and calcine at high temperature to obtain 390g of ytterbium oxide. The sample was taken and GD-MS was used to detect the content of transition elements in ytterbium oxide: Fe = 0.06ug / g, Cr < 0.05ug / g, Cu < 0.05ug / g, Ni < 0.05ug / g.

[0024] Example 2

[0025] Take 10L of ytterbium chloride solution with a rare earth ion concentration of 0.4mol / L (relative purity of rare earth 99.99%, Fe=28ug / ml, Cr=0.12ug / ml, Cu=0.22ug / ml, Ni=0.05ug / ml), take 906.2g of refined oxalic acid to prepare 7.55L of refined oxalic acid solution with a concentration of 120g / L; add the refined oxalic acid solution to the ytterbium chloride solution under stirring for precipitation reaction, when the oxalic acid solution is added to 6.8L, add 15.76g of a complexing agent with a mass ratio of salicylic acid 70%+acetylacetone 30%, continue stirring, and then add the remaining oxalic acid solution 0.75L to obtain ytterbium oxalate slurry; filter, wash the precipitate until the wash water is neutral, dehydrate, and calcine at high temperature to obtain 782g of ytterbium oxide. The samples were taken and GD-MS was used to detect the content of transition elements in ytterbium oxide: Fe<0.05ug / g, Cr<0.05ug / g, Cu<0.05ug / g, Ni<0.05ug / g.

[0026] Example 3

[0027] Take 10L of ytterbium chloride solution with a rare earth ion concentration of 0.6mol / L (relative purity of rare earth 99.99%, Fe=38ug / ml, Cr=0.18ug / ml, Cu=0.32ug / ml, Ni=0.06ug / ml), take 1418.4g of refined oxalic acid to prepare 14.18L of refined oxalic acid solution with a concentration of 100g / L; add the refined oxalic acid solution to the ytterbium chloride solution under stirring for precipitation reaction, when the oxalic acid solution is added to 12.06L, add 59.1g of a complexing agent with a mass ratio of salicylic acid 80% + acetylacetone 20%, continue stirring, and then add the remaining oxalic acid solution 2.12L to obtain ytterbium oxalate slurry; filter, wash the precipitate until the wash water is neutral, dehydrate, and calcine at high temperature to obtain 1173g of ytterbium oxide. The samples were taken and GD-MS was used to detect the content of transition elements in ytterbium oxide: Fe<0.05ug / g, Cr<0.05ug / g, Cu<0.05ug / g, Ni<0.05ug / g.

[0028] Example 4

[0029] Take 10L of ytterbium chloride solution with a rare earth ion concentration of 0.8mol / L (relative purity of rare earth 99.99%, Fe=50ug / ml, Cr=0.22ug / ml, Cu=0.42ug / ml, Ni=0.08ug / ml), take 1891.2g of refined oxalic acid to prepare 18.91L of refined oxalic acid solution with a concentration of 100g / L; add the refined oxalic acid solution to the ytterbium chloride solution under stirring for precipitation reaction, when the oxalic acid solution is added to 16.08L, add 47.3g of a complexing agent with a mass ratio of salicylic acid 80%+acetylacetone 20%, continue stirring, and then add the remaining oxalic acid solution 2.83L to obtain ytterbium oxalate slurry; filter, wash the precipitate until the wash water is neutral, dehydrate, and calcine at high temperature to obtain 1565g of ytterbium oxide. The samples were taken and GD-MS was used to detect the content of transition elements in ytterbium oxide: Fe<0.05ug / g, Cr<0.05ug / g, Cu<0.05ug / g, Ni<0.05ug / g.

[0030] Example 5

[0031] Take 10L of ytterbium chloride solution with a rare earth ion concentration of 1mol / L (relative purity of rare earth 99.99%, Fe=68ug / ml, Cr=0.28ug / ml, Cu=0.50ug / ml, Ni=0.11ug / ml), take 2462.5g of refined oxalic acid to prepare 30.78L of refined oxalic acid solution with a concentration of 80g / L; add the refined oxalic acid solution to the ytterbium chloride solution under stirring for precipitation reaction, when the oxalic acid solution is added to 24.63L, add 197g of a complexing agent with a mass ratio of salicylic acid 90% + acetylacetone 10%, continue stirring, and then add the remaining oxalic acid solution 6.15L to obtain ytterbium oxalate slurry; filter, wash the precipitate until the wash water is neutral, dehydrate, and calcine at high temperature to obtain 1954g of ytterbium oxide. The sample was taken and GD-MS was used to detect the content of transition elements in ytterbium oxide: Fe = 0.05ug / g, Cr < 0.05ug / g, Cu < 0.05ug / g, Ni < 0.05ug / g.

[0032] Comparative Example 1

[0033] Take 10L of ytterbium chloride solution with a rare earth ion concentration of 0.8mol / L (relative purity of rare earth 99.99%, Fe = 50ug / ml, Cr = 0.22ug / ml, Cu = 0.42ug / ml, Ni = 0.08ug / ml), take 1891.2g of refined oxalic acid to prepare 18.91L of refined oxalic acid solution with a concentration of 100g / L; add the refined oxalic acid solution to the ytterbium chloride solution under stirring for precipitation reaction to obtain ytterbium oxalate slurry; filter, wash the precipitate until the washing water is neutral, dehydrate, and high-temperature calcination to obtain 1566g of ytterbium oxide. Samples are taken and GD-MS is used to detect the transition element content in ytterbium oxide: Fe = 1.65ug / g, Cr = 0.85ug / g, Cu = 0.68ug / g, Ni = 0.32ug / g.

[0034] Comparative Example 2

[0035] Take 10L of ytterbium chloride solution with a rare earth ion concentration of 0.6mol / L (relative purity of rare earth 99.99%, Fe=38ug / ml, Cr=0.18ug / ml, Cu=0.32ug / ml, Ni=0.06ug / ml), take 1300.2g of refined oxalic acid to prepare 13L of refined oxalic acid solution with a concentration of 100g / L; add the refined oxalic acid solution to the ytterbium chloride solution under stirring for precipitation reaction to obtain ytterbium oxalate slurry; filter, wash the precipitate until the washing water is neutral, dehydrate, and high-temperature calcination to obtain 1171g of ytterbium oxide. Samples were taken and GD-MS was used to detect the transition element content in ytterbium oxide: Fe=1.43ug / g, Cr=0.68ug / g, Cu=0.75ug / g, Ni=0.35ug / g.

[0036] Table 1 - Comparison of results of various embodiments

[0037]

[0038] It can be clearly seen from the results of the examples and comparative examples that the method of the present invention can effectively reduce the content of Fe, Cr, Cu and Ni impurity elements in ytterbium oxide.

[0039] Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. It is not necessary and impossible to list all the implementation methods exhaustively. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description, and the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for preparing ytterbium oxide for a target material, comprising adding a refined oxalic acid solution to an ytterbium chloride solution for precipitation reaction to obtain ytterbium oxalate, and washing, dehydrating and calcining to obtain ytterbium oxide for a target material; characterized in that: When the refined oxalic acid solution is added to 80-95% of the total oxalic acid consumption during the precipitation reaction, a complexing agent is added to the precipitation slurry. The complexing agent is a combination of salicylic acid and acetylacetone. The mass ratio of salicylic acid in the complexing agent is 60-90% of the composition. The mass of the complexing agent added is 1-10% of the amount of rare earth REO in the ytterbium chloride reaction solution.

2. The preparation method according to claim 1, characterized in that: The added mass of the complexing agent is 2-5% of the amount of rare earth REO in the ytterbium chloride reaction solution.

3. The preparation method according to claim 1, characterized in that: When the refined oxalic acid solution is added to 85-90% of the total oxalic acid consumption, add the complexing agent.

4. The preparation method according to claim 1, characterized in that: The mass ratio of salicylic acid in the complexing agent to the composition is 70-80%.

5. The preparation method according to claim 1, characterized in that: The relative purity of the ytterbium chloride solution is Yb2O3 / REO≥99.99%.

6. The preparation method according to claim 1, characterized in that: The rare earth ion concentration of the ytterbium chloride solution is 0.2-1.0 mol / L.

7. The preparation method according to claim 1, characterized in that: The concentration of the refined oxalic acid solution is 50-150 g / L, and the mass ratio of oxalic acid to the desired precipitated REO is (1.1-1.25):1.

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