Preparation method of high-fluidity tantalum oxide

Abstract

The invention belongs to the technical field of metallurgy, and particularly relates to a preparation method of high-fluidity tantalum oxide. According to the method, ammonium carbonate is adopted as a precipitator, ammonium carbonate can react with various metal ions to generate insoluble precipitates, high selective precipitates are achieved, precipitation reaction can be accurately controlled, and side reactions and unnecessary impurity precipitates are reduced. By-products of the reaction of ammonium carbonate and fluotantalic acid are water and carbon dioxide, and new impurities are not introduced, so that the quality of the final product is favorably improved. The preparation method provided by the invention is easy to operate and control, the solution with the required concentration is prepared, and the precipitation rate and degree can be conveniently controlled in the reaction process; meanwhile, complex equipment and strict condition control are not needed, laboratory and industrial field operation is facilitated, and equipment investment and operation and maintenance cost are reduced; by-products can be effectively recycled, environmental pollution is reduced, and the requirement of sustainable development is met.

Description

Technical Field

[0001] The present invention belongs to the field of metallurgical technology, and particularly relates to a method for preparing tantalum oxide with high fluidity. Background Art

[0002] As an important inorganic compound, tantalum oxide has a wide range of applications in many fields. In the electronic industry, tantalum oxide is widely used in the manufacture of components such as capacitors, varistors, and thermistors. Its high dielectric constant and good high-temperature resistance make it an important material in electronic components. In the field of catalysts, tantalum oxide is used as a carrier material for catalysts, used in reactions such as catalytic cracking of heavy hydrocarbons and oxidation of methane, with good stability and activity. In the ceramic industry, tantalum oxide is also widely used in the preparation of high-temperature ceramics, protective coatings, and other fields. In summary, tantalum oxide has important application values in the electronic industry, catalyst field, and ceramic industry, playing an irreplaceable role in promoting the development of these industries.

[0003] With the development of high-tech materials, the quality requirements for tantalum oxide are getting higher and higher, especially more index requirements are put forward for physical properties such as fluidity and particle size distribution. In the production process, such as powder metallurgy and ceramic manufacturing, high fluidity means that the material can be more evenly dispersed and mixed, which is crucial for obtaining a final product with uniform properties. In the pressing process, powders with good fluidity have a stronger ability to fill the mold cavity, helping to improve the forming efficiency and the dimensional accuracy of the product, and reducing defects. The increase in fluidity reduces the agglomeration phenomenon between powders, helps to maintain the dispersed state of the powders, and facilitates subsequent processing and applications. In high-temperature treatment processes such as sintering, the good fluidity of the powders helps to obtain a higher density and more uniform microstructure, thereby improving the mechanical properties, electrical properties, or other functional characteristics of the product. For applications that require precise surface treatment, such as electronic component coatings, materials with good fluidity can form a smoother surface, reducing subsequent processing steps. Due to the smoother operation, the production cycle can be shortened, the utilization rate of equipment can be increased, and thus the cost can be reduced. Good fluidity helps to reduce the loss of materials during transfer and processing, and improve the use efficiency of raw materials. Therefore, tantalum oxide with good fluidity not only optimizes the manufacturing process flow, improves the quality and consistency of products, but also may achieve economic benefits by enhancing production efficiency and reducing losses. This is particularly important for high-performance ceramics, electronic ceramics, catalysts, and other high-tech application fields.

[0004] In the traditional preparation method, the wet smelting production process of tantalum and niobium uses tantalum and niobium concentrates as raw materials. Through grinding and acid decomposition in the HF-H2SO4 system to obtain a decomposition solution, and then using the sec-octanol-HF-H2SO4-H2O extraction system for extraction and separation to obtain tantalum solution and niobium solution. Tantalum and niobium oxides are obtained through neutralization precipitation, filtration and washing, and drying and calcination. In the precipitation step, liquid ammonia, ammonia gas or ammonia water is commonly used for neutralization precipitation. However, this method has some limitations. When the concentration in a local area exceeds the solubility limit, local supersaturation occurs. The local supersaturation phenomenon often affects the uneven particle size distribution of tantalum hydroxide, and even a cyclic process of local dissolution and reprecipitation occurs, thus affecting the purity and stability of the product. Ammonia gas is volatile during the preparation process, resulting in an unstable operating environment and prone to uneven precipitation. When using liquid ammonia, the control of temperature and pressure needs to be considered, the operation complexity is high, and the requirements for operators are also high. Although the use of ammonia water is relatively convenient, the generated ammonia gas has a large volatility, which is likely to cause environmental pollution and pose a certain risk to the safety of operators. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing tantalum oxide with high fluidity. The method provided by the present invention uses raw materials with low cost, and is simple, safe and environmentally friendly in operation.

[0006] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing tantalum oxide with high fluidity, comprising the following steps:

[0008] Preheat the fluotantalic acid solution and mix it with the ammonium carbonate solution for preliminary reaction, control the pH value of the preliminary reaction end system to be alkaline, and continue the reaction to obtain crude tantalum hydroxide;

[0009] After washing the crude tantalum hydroxide until the fluorine content in the washing liquid is less than 0.2 g / L, perform calcination to obtain the tantalum oxide with high fluidity.

[0010] Preferably, the Ta2O5 content in the fluotantalic acid solution is 90-110 g / L; the concentration of the ammonium carbonate solution is 100-120 g / L;

[0011] The molar ratio of the fluotantalic acid solution to the ammonium carbonate solution is 1:1.2-2.

[0012] Preferably, the mixing process is as follows: simultaneously pump the preheated fluotantalic acid solution and the ammonium carbonate solution into the reaction vessel;

[0013] The pumping rate of the fluotantalic acid solution is 2-8 L / min; the pumping rate of the ammonium carbonate solution is 3-16 L / min.

[0014] Preferably, the temperature of preheating, the temperature of preliminary reaction, and the temperature of continuous reaction are independently 80 - 90 °C.

[0015] Preferably, both the preliminary reaction and the continuous reaction are carried out under stirring conditions, and the rotation speed of the stirring is 250 - 450 rpm;

[0016] The time of the preliminary reaction is 120 - 180 min; the time of the continuous reaction is 30 - 60 min.

[0017] Preferably, the pH value of the alkalinity is 8.0 - 9.0.

[0018] Preferably, the cleaning process is as follows:

[0019] Mix the crude tantalum hydroxide with water, adjust the pH value of the system to 8.0 - 9.0, then after stirring and solid - liquid separation, repeat the above steps until the fluorine content in the washing liquid is less than 0.2 g / L;

[0020] The water is deionized water, and the temperature of the deionized water is 55 - 65 °C;

[0021] The reagent used to adjust the pH value of the system is ammonium carbonate solution;

[0022] The stirring time is 30 - 60 min; the number of repetitions is 3 - 5 times.

[0023] Preferably, before calcination, it further includes drying the tantalum hydroxide obtained after cleaning, and the drying temperature is 85 - 105 °C, and the time is 12 - 16 h.

[0024] Preferably, the calcination temperature is 860 - 1050 °C, and the heat - preservation time is 8 - 10 h.

[0025] Preferably, after calcination, it further includes cooling the obtained material to room temperature and then screening; the aperture of the sieve used for screening is 60 mesh.

[0026] The present invention provides a method for preparing tantalum oxide with high fluidity, comprising the following steps: preheat the fluotantalic acid solution and then mix it with ammonium carbonate solution, carry out a preliminary reaction, control the pH value of the system at the end of the preliminary reaction to be alkaline, and continue the reaction to obtain crude tantalum hydroxide; after cleaning the crude tantalum hydroxide until the fluorine content in the washing liquid is less than 0.2 g / L, carry out calcination to obtain the tantalum oxide with high fluidity.

[0027] The present invention uses ammonium carbonate as a precipitant. Ammonium carbonate can react with a variety of metal ions to generate insoluble precipitates, has high selective precipitation, helps to accurately control the precipitation reaction, and reduces side reactions and unnecessary impurity precipitation. The by-products of the reaction between ammonium carbonate and fluorotantalic acid are water and carbon dioxide, which do not introduce new impurities and help to improve the quality of the final product. The tantalum oxide obtained by the preparation method provided by the present invention has a regular shape (sphere), and the friction between the particles is small, which can further improve the fluidity and dispersibility of the particles. The preparation method provided by the present invention is easy to operate and control, and is prepared into a solution of the required concentration, which is convenient for controlling the precipitation rate and degree during the reaction process; at the same time, it does not require complex equipment and strict condition control, is convenient for laboratory and industrial field operation, and reduces equipment investment and operation and maintenance costs; it can effectively recover by-products (ammonium and fluorine-containing wash water can be further processed to prepare other chemicals: ammonium fluoride and ammonium bifluoride), reduces environmental pollution, and meets the requirements of sustainable development. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing high-fluidity tantalum oxide, comprising the following steps:

[0029] Preheating the fluorotantalate solution and mixing it with the ammonium carbonate solution to carry out a preliminary reaction, controlling the pH value of the system at the end point of the preliminary reaction to be alkaline, and continuing the reaction to obtain a crude tantalum hydroxide product;

[0030] The crude tantalum hydroxide is washed until the fluorine content in the washing liquid is less than 0.2 g / L, and then calcined to obtain the high-fluidity tantalum oxide.

[0031] The present invention preheats a fluorotantalate solution and mixes it with an ammonium carbonate solution to carry out a preliminary reaction, controls the pH value of the system at the end point of the preliminary reaction to be alkaline, and continues the reaction to obtain a crude tantalum hydroxide product.

[0032] In the present invention, the Ta2O5 content in the fluorotantalate solution is preferably 90-110 g / L, specifically 93 g / L, 95 g / L, 97 g / L, 100 g / L, 102 g / L, 106 g / L, 108 g / L, and 110 g / L; the concentration of the ammonium carbonate solution is 100-120 g / L, specifically 100 g / L, 105 g / L, 110 g / L, 115 g / L, and 120 g / L; the molar ratio of the fluorotantalate solution to the ammonium carbonate solution is preferably 1:1.2-2, specifically 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, and 1:2.

[0033] In the present invention, the preheating temperature is preferably 80 - 90°C, and specifically can be 80°C, 82°C, 85°C, 88°C, 90°C. In the present invention, the mixing process is preferably as follows: simultaneously pump the preheated tantalum fluoride solution and ammonium carbonate solution into the reaction vessel; the pumping rate of the tantalum fluoride solution is preferably 2 - 8 L / min, and specifically can be 2 L / min, 4 L / min, 5 L / min, 6 L / min, 8 L / min; the pumping rate of the ammonium carbonate solution is preferably 3 - 16 L / min, and specifically can be 3 L / min, 5 L / min, 8 L / min, 10 L / min, 12 L / min, 15 L / min, 16 L / min. In the present invention, the reaction vessel is preferably a reaction kettle. In the present invention, the temperature of the preliminary reaction and the temperature of the subsequent reaction are independently preferably 80 - 90°C, and specifically can be 80°C, 82°C, 85°C, 88°C, 90°C. In the present invention, both the preliminary reaction and the subsequent reaction are preferably carried out under stirring conditions, and the stirring speed is preferably 250 - 450 rpm, and specifically can be 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm; the time of the preliminary reaction is preferably 120 - 180 min, and specifically can be 120 min, 150 min, 180 min; the time of the subsequent reaction is preferably 30 - 60 min, and specifically can be 30 min, 40 min, 50 min, 60 min. In the present invention, after the subsequent reaction, it is also preferably to perform solid-liquid separation on the obtained system.

[0034] In the present invention, the pH value of the alkaline is preferably 8.0 - 9.0.

[0035] After obtaining the crude tantalum hydroxide, in the present invention, the crude tantalum hydroxide is washed until the fluorine content in the washing liquid is less than 0.2 g / L, and then calcined to obtain the highly flowable tantalum oxide.

[0036] In the present invention, the washing process is preferably as follows: mix the crude tantalum hydroxide and water, adjust the pH value of the system to 8.0 - 9.0, then after stirring and solid-liquid separation, repeat the above steps until the fluorine content in the washing liquid is less than 0.2 g / L; the water is preferably deionized water, and the temperature of the deionized water is preferably 55 - 65°C; the reagent used to adjust the pH value of the system is preferably ammonium carbonate solution; the stirring time is preferably 30 - 60 min; the number of repetitions is preferably 3 - 5 times, and specifically can be 3 times, 4 times, 5 times.

[0037] In the present invention, before the calcination, it is also preferably to dry the tantalum hydroxide obtained after washing, and the drying temperature is preferably 85 - 105°C, and the time is preferably 12 - 16 h.

[0038] In the present invention, the calcination temperature is preferably 860 - 1050 °C, specifically it can be 860 °C, 880 °C, 900 °C, 920 °C, 950 °C, 980 °C, 1000 °C, 1050 °C; the heat preservation time is preferably 8 - 10 h, specifically it can be 8 h, 9 h, 10 h. In the present invention, the crucible used for calcination is preferably a tantalum crucible.

[0039] In the present invention, after the calcination, it preferably further includes cooling the obtained material to room temperature and then performing screening; the aperture of the sieve mesh used for screening is preferably 60 mesh; the screening method is preferably a vibratory screen.

[0040] Unless otherwise specified, the materials and equipment used in the present invention are all commercially available products in the art.

[0041] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0042] Example 1

[0043] Preheat the tantalum hexafluoride solution (with Ta2O5 content of 108 g / L) to 80 °C, and add the preheated tantalum hexafluoride solution and ammonium carbonate solution (concentration of 110 g / L) into a reaction kettle at 80 °C at the same time at a rate of 3.83 L / min and 5.36 L / min respectively according to a molar ratio of 1:1.4 by using a metering pump for preliminary reaction, with a stirring rate of 350 rpm, a reaction time of 150 min, controlling the pH value at the reaction end point to be 8.5, and continuing to stir for 30 min, and then obtaining crude tantalum hydroxide through solid-liquid separation;

[0044] Mix the obtained crude tantalum hydroxide with deionized water at 55 °C, adjust the pH value of the system to 8.5 by using ammonium carbonate solution, stir for 30 min and then perform solid-liquid separation, and repeat the above process 4 times until the fluorine content in the washing liquid is 0.15 g / L;

[0045] Uniformly spread the obtained tantalum hydroxide filter cake on a tray and place it in a vacuum drying oven, with a drying temperature of 100 °C and a heat preservation time of 12 hours;

[0046] Load 1.0 kg of dried tantalum hydroxide into a tantalum crucible, place it in a pusher furnace for calcination, control the temperature at 860 °C, with a heat preservation time of 10 h, wait until it cools to room temperature, and perform screening through a 60-mesh vibratory screen to obtain tantalum oxide;

[0047] Liquidity detection: After tantalum oxide is freely poured into a funnel at a certain height and naturally accumulates on a horizontal plane, the angle formed between the formed conical pile and the horizontal plane is 35°.

[0048] Example 2

[0049] Preheat the fluotantalic acid solution (with a Ta2O5 content of 93 g / L) to 80 °C. Then, according to a molar ratio of 1:1.2, use metering pumps to simultaneously add the preheated fluotantalic acid solution and ammonium carbonate solution (concentration of 110 g / L) to a reaction kettle at 80 °C at rates of 5.56 L / min and 6.67 L / min respectively for preliminary reaction. The stirring rate is 300 rpm, the reaction time is 120 min, the pH value at the reaction end point is controlled at 8.5, and continue stirring for 30 min. After solid-liquid separation, obtain the crude tantalum hydroxide product;

[0050] Mix the obtained crude tantalum hydroxide product with deionized water at 55 °C, adjust the pH value of the system to 8.5 with ammonium carbonate solution, stir for 30 min and then perform solid-liquid separation. Repeat the above process 4 times until the fluorine content in the washing liquid is 0.11 g / L;

[0051] Evenly spread the obtained tantalum hydroxide filter cake on a tray and place it in a vacuum drying oven. The drying temperature is 100 °C and the heat preservation time is 12 hours;

[0052] Load 1.0 kg of dried tantalum hydroxide into a tantalum crucible and place it in a pusher furnace for calcination. The temperature is controlled at 860 °C and the heat preservation time is 10 h. After cooling to room temperature, sieve through a 60-mesh rotary vibrating screen to obtain tantalum oxide;

[0053] Liquidity detection: After tantalum oxide is freely poured into a funnel at a certain height and naturally accumulates on a horizontal plane, the angle formed between the formed conical pile and the horizontal plane is 38°.

[0054] Example 3

[0055] Preheat the fluotantalic acid solution (with a Ta2O5 content of 110 g / L) to 85 °C. Then, according to a molar ratio of 1:1.5, use metering pumps to simultaneously add the preheated fluotantalic acid solution and ammonium carbonate solution (concentration of 110 g / L) to a reaction kettle at 85 °C at rates of 2.87 L / min and 4.31 L / min respectively for preliminary reaction. The stirring rate is 400 rpm, the reaction time is 180 min, the pH value at the reaction end point is controlled at 8.5, and continue stirring for 30 min. After solid-liquid separation, obtain the crude tantalum hydroxide product;

[0056] Mix the obtained crude tantalum hydroxide with deionized water at 55°C, adjust the pH value of the system to 8.5 using ammonium carbonate solution, stir for 30 minutes and then perform solid-liquid separation. Repeat the above process 4 times until the fluorine content in the washing liquid is 0.08 g / L;

[0057] Uniformly spread the obtained tantalum hydroxide filter cake on a tray and place it in a vacuum drying oven. The drying temperature is 100°C and the heat preservation time is 12 hours;

[0058] Load 1.0 kg of dried tantalum hydroxide into a tantalum crucible and place it in a pusher furnace for calcination. The temperature is controlled at 860°C and the heat preservation time is 10 h. After cooling to room temperature, sieve through a 60-mesh rotary vibrating screen to obtain tantalum oxide;

[0059] Flowability detection: After tantalum oxide is freely poured from a funnel at a certain height and naturally accumulates on a horizontal plane, the angle formed between the formed push cone and the horizontal plane is 34°.

[0060] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, not all embodiments. Other embodiments can also be obtained based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A preparation method of tantalum oxide with high fluidity, characterized in that, It includes the following steps: Preheat the tantalum fluoride solution and mix it with the ammonium carbonate solution for a preliminary reaction. Control the pH value of the system at the end point of the preliminary reaction to be alkaline and continue the reaction to obtain crude tantalum hydroxide; After washing the crude tantalum hydroxide until the fluorine content in the washing liquid is less than 0.2 g / L, calcine it to obtain the highly fluid tantalum oxide.

2. The preparation method according to claim 1, characterized in that, The Ta2O5 content in the tantalum fluoride solution is 90 - 110 g / L; the concentration of the ammonium carbonate solution is 100 - 120 g / L; The molar ratio of the tantalum fluoride solution to the ammonium carbonate solution is 1:1.2 - 2.

3. The preparation method according to claim 1, characterized in that, The mixing process is as follows: Pump the preheated tantalum fluoride solution and the ammonium carbonate solution into the reaction vessel simultaneously; The pumping rate of the tantalum fluoride solution is 2 - 8 L / min; the pumping rate of the ammonium carbonate solution is 3 - 16 L / min.

4. The preparation method according to claim 1, characterized in that, The temperature of preheating, the temperature of the preliminary reaction, and the temperature of the continued reaction are independently 80 - 90 °C.

5. The preparation method according to claim 4, characterized in that, Both the preliminary reaction and the continued reaction are carried out under stirring conditions, and the stirring speed is 250 - 450 rpm; The time of the preliminary reaction is 120 - 180 min; the time of the continued reaction is 30 - 60 min.

6. The preparation method according to claim 1, characterized in that, The pH value of the alkaline is 8.0 - 9.

0.

7. The preparation method according to claim 1, wherein The washing process is as follows: Mix the crude tantalum hydroxide with water, adjust the pH value of the system to 8.0 - 9.0, then after stirring and solid-liquid separation, repeat the above steps until the fluorine content in the washing liquid is less than 0.2 g / L; The water is deionized water, and the temperature of the deionized water is 55 - 65 °C; The reagent used to adjust the pH value of the system is the ammonium carbonate solution; The stirring time is 30 - 60 min; the number of repetitions is 3 - 5 times.

8. The preparation method according to claim 1, characterized in that, Before calcination, it also includes drying the tantalum hydroxide obtained after washing. The drying temperature is 85 - 105 °C and the time is 12 - 16 h.

9. The preparation method according to claim 1, characterized in that, The calcination temperature is 860 - 1050 °C and the holding time is 8 - 10 h.

10. The preparation method according to claim 1, wherein After calcination, it also includes cooling the obtained material to room temperature and then screening; the aperture of the sieve used for screening is 60 mesh.