A preparation device and preparation method of high-purity barium carbonate

Abstract

The invention belongs to the technical field of electronic material synthesis, and discloses a preparation device and a preparation method of high-purity barium carbonate. The invention utilizes the principle of precipitation reaction, takes high-purity barium hydroxide octahydrate as raw material, and fully considers the low solubility of barium hydroxide octahydrate at room temperature, adopts heating to improve its solubility, and stirs and dissolves it in hot water; by arranging a gas distribution plate at the bottom of the reactor, the gas can be evenly dispersed in the solution, and the precipitation reaction speed and the uniformity of the finished product are improved; and by adopting a circulating ventilation method, the utilization rate of carbon dioxide reaches 100%. The barium carbonate slurry produced by the reaction is filtered, dehydrated, and dried to obtain high-purity barium carbonate. The entire reaction process is environmentally friendly, has a high synthesis conversion rate, a high carbon dioxide utilization rate, and a high product purity, and fully meets the use requirements of the electronics industry.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic material synthesis, and specifically relates to a preparation device and a preparation method of high-purity barium carbonate. Background Art

[0002] Barium carbonate, chemical formula BaCO3, molecular weight 197.35, hexagonal fine crystals or white powder, insoluble in water. Barium carbonate has extremely wide applications in the electronics, instrumentation, and metallurgical industries, especially in the ceramics and coatings industries. With the advent of the 5G era, barium carbonate is widely used in the manufacture of various electronic components such as MLCC chip multilayer ceramic capacitors, PTC thermistors, and ultrasonic transducers. It is also an important raw material for the synthesis of nano barium titanate (BaTiO3) and has a very broad market prospect.

[0003] The main methods for preparing barium carbonate are carbonization, double decomposition, and toxic heavy petrochemicals.

[0004] The carbonization method is to introduce carbon dioxide into the barium sulfide solution for carbonization to obtain barium carbonate slurry, which is then desulfurized, washed, vacuum filtered, dried at 300°C, and crushed to obtain the finished barium carbonate product.

[0005] BaS+CO2+H2O=BaCO3+H2S

[0006] The double decomposition method is to react barium sulfide with ammonium carbonate, and then wash, filter, dry, etc. to obtain the finished barium carbonate. It can also be produced by reacting barium chloride with potassium carbonate.

[0007] BaS+(NH4)2CO3=BaCO3+(NH4)2S

[0008] BaCl2+K2CO 3＝ BaCO3+2KCl

[0009] The barium carbonate method is to react barium ore powder with ammonium salt to generate soluble barium salt, and at the same time recover the ammonium carbonate for use. The soluble barium salt is added to ammonium carbonate to precipitate refined barium carbonate, which is then filtered and dried to make the finished product.

[0010] BaCO3+2HCl=BaCl2+H2O+CO2

[0011] BaCl2+2NH4OH=Ba(OH)2+2NH4Cl

[0012] Ba(OH)2+CO2=BaCO3+H2O

[0013] Since barium hydroxide has low solubility at room temperature and the above preparation method produces by-products such as hydrogen sulfide and ammonium carbonate, the entire process is complicated, the synthesis conversion rate is low, the raw material utilization rate is low, the environmental pollution is serious, and the impurity content of the finished barium carbonate product is high. Summary of the invention

[0014] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a preparation device and a preparation method of high-purity barium carbonate. The principle of precipitation reaction is utilized, high-purity barium hydroxide octahydrate is used as a raw material, the raw material is stirred and dissolved in hot water, and carbon dioxide gas is circulated into the hot solution to produce barium carbonate precipitation by reaction. The slurry is dehydrated and dried to obtain high-purity barium carbonate. The entire reaction process is environmentally friendly, has a high synthesis conversion rate, a high carbon dioxide utilization rate, and a high product purity, and fully meets the use requirements of the electronics industry.

[0015] The technical solution adopted by the present invention is: a preparation device for high-purity barium carbonate, including a reaction system and a gas supply system, wherein the reaction system is composed of a reaction kettle and a stirring device;

[0016] The reactor is a jacket structure, the inner cavity of the jacket is filled with heat-conducting oil, and a heating resistance wire is provided. The heat-conducting oil in the reactor jacket is heated by the resistance wire, and the heat is transferred to the reactor. A gas distribution plate is provided at the bottom of the reactor inner cavity. A solid feeding port, a water feeding port, a pressure gauge port, a thermometer port and an air outlet are provided on the upper head of the reactor body. The thermometer is fixed on the thermometer port and inserted into the reactor inner cavity; a discharge port, a heat-conducting oil inlet and an air inlet are provided on the lower head of the reactor body, and a heat-conducting oil outlet is provided in the upper middle part of the reactor body; the solid feeding port, the water feeding port, the pressure gauge port, the thermometer port, the air outlet, the discharge port and the air inlet are all in communication with the reactor inner cavity, and the heat-conducting oil inlet and the heat-conducting oil outlet are all in communication with the inner cavity of the jacket. The parts of the inner wall of the reactor that contact the materials are all made of acid- and alkali-resistant alloy materials, and the surface is polished;

[0017] The stirring device is composed of a motor, a reducer, a stirring rod and a stirring paddle. The reducer and the motor are fixed on the top of the reactor, the stirring rod is inserted into the inner cavity of the reactor, and the stirring paddle is fixed on the stirring rod.

[0018] The gas supply system consists of a gas source, a switch valve, a gas check valve, a liquid check valve, a pressure gauge, a vacuum pump and a pipeline. The gas source is compressed carbon dioxide. The switch valve is interlocked with the pressure gauge. When the gas pressure in the reactor is insufficient, the switch valve automatically opens to replenish carbon dioxide. The two ends of the pipeline are respectively connected to the gas outlet and the gas inlet of the reactor. The vacuum pump is arranged on the pipeline of the gas supply system to circulate and pump the carbon dioxide gas into the reactor for full utilization. The vacuum pump has an automatic protection function to ensure the safety of the system.

[0019] The gas distribution plate is a hollow disc. The air inlet of the reactor is connected to the inner cavity of the disc through the air inlet hole opened on the bottom of the disc. A number of air outlet holes are evenly distributed on the bottom of the disc, which can not only make the gas evenly dispersed in the solution, but also avoid the generated barium carbonate from clogging the air outlet holes.

[0020] In order to solve the above technical problems, the present invention also provides a method for preparing high-purity barium carbonate, which uses barium hydroxide octahydrate, carbon dioxide and water as raw materials. After the barium hydroxide octahydrate is heated and dissolved in water, carbon dioxide gas is circulated and introduced. The raw materials are stirred and reacted in a closed reactor to produce precipitation. After dehydration and drying, high-purity barium carbonate can be prepared.

[0021] The method for preparing high-purity barium carbonate of the present invention adopts the device for preparing high-purity barium carbonate of the present invention, and comprises the following steps:

[0022] (1) Close the discharge port and add high-purity water into the reactor. The amount of high-purity water added is 50-60% of the volume of the reactor;

[0023] (2) adding accurately weighed barium hydroxide octahydrate into the reactor through the solid feed port, wherein the added mass of barium hydroxide octahydrate is less than 90% of the added mass of high-purity water;

[0024] (3) Close the feed port and water inlet, check the pressure gauge and switch valve, and confirm that the entire reaction system is in a closed state;

[0025] (4) starting the stirring device, controlling the stirring rod speed to 0-80 RPM, performing mixing and stirring, and at the same time heating the heat transfer oil in the jacket of the reactor through a resistance wire to control the temperature in the reactor to be greater than 80° C.;

[0026] (5) After the barium hydroxide octahydrate is completely dissolved, open the switch valve and introduce carbon dioxide gas into the reactor to make the pressure in the reactor ≥ 0.1 MPa. When the pressure in the reactor is lower than 0.1 MPa, the switch valve automatically opens to add carbon dioxide;

[0027] (6) Turn on the vacuum pump to circulate the unreacted carbon dioxide into the reactor until the carbon dioxide is completely reacted;

[0028] (7) The barium carbonate slurry generated by the reaction is filtered, dehydrated, and dried to obtain high-purity barium carbonate. The dehydration and drying processes of the slurry are both carried out in a clean environment, and the drying temperature is lower than 300° C.

[0029] The present invention utilizes the principle of precipitation reaction, uses high-purity barium hydroxide octahydrate as raw material, and fully considers the low solubility of barium hydroxide octahydrate at room temperature, adopts heating to improve its solubility, and stirs and dissolves it in hot water; by setting a gas distribution plate, the gas can be evenly dispersed in the solution, thereby improving the precipitation reaction speed and the uniformity of the finished product; and adopts a circulating ventilation method to achieve 100% utilization of carbon dioxide. The barium carbonate slurry produced by the reaction is filtered, dehydrated, and dried to obtain high-purity barium carbonate. The entire reaction process is environmentally friendly, has a high synthesis conversion rate, a high carbon dioxide utilization rate, and a high product purity, which fully meets the use requirements of the electronics industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of a device for preparing high-purity barium carbonate in Example 1.

[0031] Figure 2 1 is a top view of the reaction system of Example 1.

[0032] Figure 3 3 is a top view of the gas distribution plate of Example 1.

[0033] Figure 4 This is the XRD spectrum of the barium carbonate prepared in Example 2.

[0034] Figure 5 This is a SEM image of the barium carbonate prepared in Example 2. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] Embodiment 1

[0037] A preparation device for high-purity barium carbonate, such as Figure 1 — Figure 3 As shown, it includes a reaction system and a gas supply system, wherein the reaction system is composed of a reaction kettle 100 and a stirring device 200;

[0038] The reactor body 101 of the reactor 100 is a jacket structure, the inner cavity of the jacket is filled with heat-conducting oil 102, and a heating resistor 103 is provided. The heat-conducting oil 102 in the jacket is heated by the resistor 103, and the heat is transferred to the reactor 100. A gas distribution plate 104 is provided at the bottom of the inner cavity of the reactor 100. The gas distribution plate 104 is a hollow disc, including a disc top surface and a disc bottom surface 104a. The disc top surface and the disc bottom surface 104a form a disc inner cavity. There are air inlet holes 104b for air intake on the disc bottom surface 104a, and a plurality of air outlet holes 104c are evenly distributed on the disc bottom surface 104a, which can not only make the gas evenly dispersed in the solution, but also avoid the generated barium carbonate from clogging the air outlet holes 104c. The upper cover of the kettle body 101 is provided with a solid feeding port 105, a water feeding port 106, a pressure gauge port 107, a thermometer port 108 and an air outlet 109. The thermometer is fixed at the thermometer port 108 and inserted into the inner cavity of the reactor 100; the lower cover of the kettle body 101 is provided with a discharge port 110, a heat transfer oil inlet 111 and an air inlet 112, and the upper middle part of the kettle body 101 is provided with a heat transfer oil outlet 113; the solid feeding port 105, the water feeding port 106, the pressure gauge port 107, the temperature gauge port 108 and the air outlet 109 are provided. The meter port 108, the gas outlet 109 and the discharge port 110 are all connected to the inner cavity of the reactor 100; the gas inlet 112 is connected to the gas inlet hole 104b of the gas distribution plate 104, which can introduce the gas into the inner cavity of the disc and disperse it into the solution through the gas outlet holes 104c evenly distributed on the bottom surface 104a of the disc; the heat transfer oil inlet 111 and the heat transfer oil outlet 113 are both connected to the inner cavity of the jacket, and the parts of the inner wall of the reactor 100 that contact the materials are all made of acid and alkali resistant alloy materials, and the surface is polished;

[0039] The stirring device 200 is composed of a motor 201, a reducer 202, a stirring rod 203 and a stirring paddle 204. The reducer 202 and the motor 201 are fixed on the top of the reactor 100, the stirring rod 203 is inserted into the inner cavity of the reactor 100, and the stirring paddle 204 is fixed on the stirring rod 203;

[0040] The gas supply system is composed of a gas source 301, a switch valve 302, a gas check valve 303, a liquid check valve 304, a pressure gauge 305, a vacuum pump 306 and a pipeline 307. The gas source 301 is compressed carbon dioxide. The switch valve 302 is interlocked with the pressure gauge 305. When the gas pressure in the reactor 100 is insufficient, the switch valve 302 automatically opens to replenish carbon dioxide. The two ends of the pipeline 307 are respectively connected to the gas outlet 109 and the gas inlet 112 of the reactor 100. The vacuum pump 306 is arranged on the pipeline 307 of the gas supply system to circulate and pump the carbon dioxide gas into the reactor 100 for full utilization. The vacuum pump 306 has an automatic protection function to ensure the safety of the system.

[0041] Embodiment 2

[0042] A method for preparing high-purity barium carbonate, using barium hydroxide octahydrate, carbon dioxide and water as raw materials, heating and dissolving the barium hydroxide octahydrate in water, then circulating carbon dioxide gas, stirring the raw materials in a closed reactor to react and produce precipitation, and then dehydrating and drying to prepare high-purity barium carbonate.

[0043] The specific steps are:

[0044] (1) Add 5000 kg of high-purity water with a resistivity of 17.5 megohms into a 10 m 3 In the reactor;

[0045] (2) Add 4000 kg of accurately weighed barium hydroxide octahydrate into the reactor;

[0046] (3) Close the solid feed port and the water feed port, check the working status of each valve and the pressure gauge 305, and confirm that the entire reaction system is in a closed state;

[0047] (4) Start the stirring device to mix and stir at a low speed, and at the same time heat the heat transfer oil to 90°C through the resistance wire, and ensure that the temperature transferred to the reactor is greater than 80°C;

[0048] (5) After the barium hydroxide octahydrate in the reactor is completely dissolved, the rotation speed is increased to 80 RPM, the switch valve is opened, and carbon dioxide gas is introduced into the reactor to make the pressure in the reactor ≥ 0.1 MPa. When the pressure in the reactor is lower than 0.1 MPa, the switch valve 302 is automatically opened to add carbon dioxide;

[0049] (6) turning on the vacuum pump to circulate the unreacted carbon dioxide into the reactor until the carbon dioxide completely reacts with the barium hydroxide dissolved in the high-purity water to produce barium carbonate;

[0050] (7) The barium carbonate slurry generated by the reaction was filtered and dehydrated in a clean environment, and dried at a temperature below 300° C. to obtain 2480 kg of high-purity barium carbonate.

[0051] Performance test and results:

[0052] In order to detect the performance and purity of the prepared barium carbonate, the barium carbonate prepared in Example 2 was used as the test sample, and the XRD patterns of the test samples were tested (such as Figure 4 ) and SEM images (as shown Figure 5 As shown in the figure), the content of metal elements in the sample was tested by ICP spectrometer.

[0053] It can be seen from the XRD spectrum that the position and intensity of the diffraction peak of the sample to be tested are consistent with the standard spectrum of barium carbonate. Analysis confirms that the product obtained by the reaction of barium hydroxide octahydrate and carbon dioxide is a single component barium carbonate phase with good crystallinity. From the SEM image, it can be seen that the barium carbonate particles are fully developed, uniform in size, and have good dispersion. In order to detect the purity of the sample, the ICP method was used to test the content of metal elements in the sample. The test results are shown in Table 1. The test results show that the entire system has high cleanliness, no impurity elements are introduced, and the product fully meets the use requirements of the electronics industry.

[0054] Table 1 Content of metal elements in the samples to be tested

[0055]

[0056] The above is only the best embodiment of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the principle of the present invention, the technical solution of the present invention can be modified or replaced by equivalents, which can also achieve the technical effect of the present invention and should also be regarded as belonging to the protection scope of the present invention.

Claims

1. A device for preparing high-purity barium carbonate, comprising a reaction system and a gas supply system, wherein the reaction system is composed of a reaction kettle and a stirring device, and is characterized in that: The reactor is of jacket structure, the inner cavity of the jacket is filled with heat transfer oil and is provided with a heating resistance wire, a gas distribution plate is provided at the bottom of the inner cavity of the reactor, a solid feeding port, a water feeding port, a pressure gauge port, a thermometer port and an air outlet are provided on the upper head of the reactor body, and the thermometer is fixed on the thermometer port and inserted into the inner cavity of the reactor; a discharge port, a heat transfer oil inlet and an air inlet are provided on the lower head of the reactor body, and a heat transfer oil outlet is provided in the middle and upper part of the reactor body; the solid feeding port, the water feeding port, the pressure gauge port, the thermometer port, the air outlet, the discharge port and the air inlet are all in communication with the inner cavity of the reactor, and the heat transfer oil inlet and the heat transfer oil outlet are all in communication with the inner cavity of the jacket; The stirring device is composed of a motor, a reducer, a stirring rod and a stirring paddle. The reducer and the motor are fixed on the top of the reactor, the stirring rod is inserted into the inner cavity of the reactor, and the stirring paddle is fixed on the stirring rod. The gas supply system is composed of a gas source, a switch valve, a gas check valve, a liquid check valve, a pressure gauge, a vacuum pump and a pipeline. The gas source is compressed carbon dioxide. The switch valve is interlocked with the pressure gauge. The two ends of the pipeline are respectively connected to the gas outlet and the gas inlet of the reactor. The vacuum pump is arranged on the pipeline of the gas supply system. The gas distribution plate is a hollow disc, the air inlet of the reactor is connected to the inner cavity of the disc through the air inlet hole opened on the bottom of the disc, and a number of air outlet holes are evenly distributed on the bottom of the disc; The inner wall of the reactor that contacts the materials is made of acid- and alkali-resistant alloy materials.

2. A method for preparing high-purity barium carbonate, characterized in that: The preparation device according to claim 1 comprises the following steps: (1) Close the discharge port and add high-purity water into the reactor. The amount of high-purity water added is 50-60% of the reactor volume; (2) Add accurately weighed barium hydroxide octahydrate into the reactor through the solid feed port, and the added mass of barium hydroxide octahydrate is less than 90% of the added mass of high-purity water; (3) Close the feed port and water port, check the pressure gauge and switch valve, and confirm that the entire reaction system is in a closed state; (4) Start the stirring device, control the speed of the stirring rod to 0-80 RPM, perform mixing and stirring, and heat the heat transfer oil in the jacket of the reactor through the resistance wire to control the temperature in the reactor to be greater than 80°C; (5) After the barium hydroxide octahydrate is completely dissolved, open the switch valve and introduce carbon dioxide gas into the reactor to make the pressure in the reactor ≥ 0.1 MPa; (6) Turn on the vacuum pump to circulate the unreacted carbon dioxide into the reactor until the carbon dioxide is completely reacted; (7) The barium carbonate slurry generated by the reaction is filtered, dehydrated, and dried to obtain high-purity barium carbonate.

3. The method for preparing high-purity barium carbonate according to claim 2, characterized in that: In step (5), the switch valve is interlocked with the pressure gauge. When the pressure in the reactor is lower than 0.1 MPa, the switch valve automatically opens to replenish carbon dioxide.

4. The method for preparing high-purity barium carbonate according to claim 2, characterized in that: In step (7), the dehydration and drying processes of the slurry are carried out in a clean environment, and the drying temperature is lower than 300°C.

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