Process for the preparation of a suspension of barium sulfate

Abstract

The application belongs to the technical field of barium compound preparation, and relates to a preparation method of suspended barium sulfate. In the method, magnesium citrate is introduced as a crystal form regulator in the initial stage of the barium sulfate precipitation reaction, and the crystal growth kinetics is cooperatively regulated by magnesium ions and citrate ions, so that flaky or fusiform high-specific-surface-area barium sulfate is obtained. The obtained product has excellent suspension stability, high crystalline purity and good redispersibility without surface modification, and is suitable for water phase and organic medium systems.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of barium compound preparation, and relates to a preparation method of suspended barium sulfate. BACKGROUND

[0002] As an important inorganic functional filler, barium sulfate is widely used in various industrial fields such as coatings, inks, plastics, papermaking, medical contrast agents and high-end composites due to its high density, excellent chemical stability, good X-ray shielding performance and low toxicity. In many application scenarios, barium sulfate often exists in the form of a suspension to ensure its uniform dispersion in the system and fully play its functional characteristics. Therefore, the stability of the suspension system directly determines the performance consistency and shelf life of the final product, and becomes one of the key indicators for measuring the application value of barium sulfate.

[0003] Traditional preparation of barium sulfate usually adopts a double decomposition reaction of sulfate and barium salt in an aqueous phase, and by controlling process parameters such as reaction temperature, concentration and stirring rate, blocky crystals with high crystallinity and good purity are obtained. Such crystal structure is dense and smooth in surface, and although it performs excellently in purity and mechanical strength, its specific surface area is generally low, usually less than 1 m2 / g. In a liquid medium, due to the lack of sufficient surface active sites and steric hindrance effect, the inter-particle van der Waals force dominates, and the density of barium sulfate is as high as 4.5 g / cm3. Under the action of gravity field, it is easy to quickly settle and form hard sediment which is difficult to redisperse. This phenomenon not only significantly shortens the physical stability period of the suspension, but also leads to performance fluctuations between batches, uneven coating or insufficient filling and other process defects in the downstream application process.

[0004] Under the condition of no external regulation, barium sulfate tends to grow along the thermodynamically most stable crystal surface, forming isotropic cubic or near-cubic block morphology, thus naturally lacking the anisotropic characteristics required to maintain colloidal stability in terms of geometric shape and surface energy distribution. Correspondingly, even if remedial measures such as adding dispersants or surface modification are taken later, it is difficult to fundamentally change the sedimentation dynamics of the particles, and the additional introduction of organic components may bring about cost increase, compatibility risk or biological safety hazards. SUMMARY

[0005] The application provides a preparation method of suspensibility barium sulfate, aiming at solving the technical problem of poor suspension stability, fast settling rate and difficult re-dispersion of barium sulfate particles in the prior art due to the dense block-like morphology. To achieve the above-mentioned application purposes, the application introduces a specific concentration of magnesium citrate as a crystal form regulator in the initial stage of the barium sulfate precipitation reaction, and performs directional intervention on the crystal face growth kinetics of barium sulfate from the source of crystal nucleation and growth, so as to obtain barium sulfate crystals with high specific surface area, specific geometric morphology (sheet or spindle) and optimized surface energy distribution, which significantly improves the suspension stability of the barium sulfate crystals in water or organic medium, while maintaining the high chemical purity and crystalline integrity.

[0006] The preparation method of suspensibility barium sulfate provided by the application comprises the following steps:

[0007] Step 1: preparing a soluble barium salt aqueous solution with a concentration of 0.5 mol / L to 2.0 mol / L, wherein the soluble barium salt is selected from any one of barium chloride, barium nitrate or barium acetate; and preparing a soluble sulfate aqueous solution with a concentration of 0.5 mol / L to 2.0 mol / L, wherein the soluble sulfate is selected from any one of sodium sulfate, potassium sulfate or ammonium sulfate;

[0008] Step 2: placing the soluble barium salt aqueous solution in a reaction container, and controlling the temperature of the reaction system to be 25 to 80 rpm to 800 rpm under stirring;

[0009] Step 3: adding a magnesium citrate aqueous solution to the reaction system, wherein the addition amount of the magnesium citrate is 0.5% to 5.0% of the molar amount of barium ions in terms of magnesium ions, the concentration of the magnesium citrate aqueous solution is 0.01 mol / L to 0.1 mol / L, and the addition mode is one-time injection or uniform dropping within 5 minutes to 30 minutes;

[0010] Step 4: within 5 minutes after the completion of the addition of the magnesium citrate, starting to drop the soluble sulfate aqueous solution into the reaction system at a dropping rate of 1 mL / min to 10 mL / min, and continuing to stir for 30 minutes to 120 minutes after the dropping process lasting for 10 minutes to 60 minutes;

[0011] Step 5: after the reaction is completed, performing solid-liquid separation on the obtained slurry, and sequentially washing the obtained solid with deionized water for 3 to 5 times, and replacing and washing the obtained solid with ethanol for 1 to 2 times, and then drying the obtained solid at 60 to 120 for 6 hours to 24 hours to obtain the suspensibility barium sulfate product.

[0012] Further, the magnesium citrate dissociates in the reaction system to generate magnesium ions and citrate ions which jointly act on the growth interface of the barium sulfate crystals. The magnesium ions have a significant difference from barium ions in terms of ion radius, and thus cannot enter the barium sulfate crystal lattice, but can selectively adsorb on the {200} crystal plane of the barium sulfate crystals to inhibit the ion deposition rate of the crystal plane through the electrostatic shielding effect; meanwhile, the citrate ions can form weak coordination complexes with the barium ions exposed on the crystal surface due to their polydentate coordination structure, and thus preferentially adsorb on the high surface energy crystal planes (such as the {110} or {210} planes), so as to change the relative growth rates of the crystal planes and induce the preferential growth of the crystals along a specific direction, and finally form a sheet-like or spindle-like morphology.

[0013] As a preferred embodiment of the present application, the magnesium citrate is added in an amount of 1.0% to 3.0% of the molar amount of barium ions, the reaction temperature is controlled at 40 to 60 , and the dropping rate of the sulfate solution is 3 mL / min to 6 mL / min. Under this process parameter, the obtained barium sulfate crystals have a regular sheet-like morphology, an average particle size (D50) of 0.8 μm to 2.5 μm, a thickness of 80 nm to 200 nm, an aspect ratio of 4:1 to 10:1, and a specific surface area of .

[0014] As another preferred embodiment of the present application, the magnesium citrate is added in an amount of 3.5% to 5.0% of the molar amount of barium ions, the reaction temperature is controlled at 65 to 80 , and the dropping rate of the sulfate solution is 7 mL / min to 10 mL / min. Under this condition, the obtained barium sulfate crystals have a spindle-like morphology, an average length of 1.5 μm to 3.0 μm, a maximum diameter of 0.3 μm to 0.6 μm, an aspect ratio of 3:1 to 6:1, and a specific surface area of .

[0015] Further, the sheet-like barium sulfate can form a brick-mud type dense stacking structure in the coating system due to its two-dimensional sheet structure, thereby significantly improving the barrier property and mechanical strength of the coating; the spindle-like barium sulfate can be easily aligned in the flow direction in the polymer matrix due to its anisotropic morphology, thereby effectively improving the tensile strength and dimensional stability of the composite material.

[0016] Further, the amount of the magnesium citrate used in the method of the present application is much lower than the addition proportion of the conventional dispersants, and the magnesium citrate itself is a food-grade additive, which is low in cost and environmentally friendly, and thus is suitable for large-scale industrial production.

[0017] Further, the present application can realize controllable switching between flaky and spindle-like morphology by regulating the concentration of magnesium citrate, reaction temperature and the dropping rate of sulfate, thereby meeting the customized needs of particle morphology in different application scenarios.

[0018] Further, the pH value of the reaction system is naturally maintained in the range of 5.5 to 7.0 during the reaction process without additional adjustment, avoiding the influence of strong acid or strong base introduction on equipment corrosion and product purity.

[0019] Further, the obtained barium sulfate also shows good dispersion stability in organic solvents such as ethanol, propylene glycol and xylene, indicating that its surface properties have universal adaptability and are suitable for application scenarios in oily systems.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] The present application introduces magnesium citrate as a crystal type regulator at the initial stage of barium sulfate precipitation reaction, realizes precise regulation of barium sulfate morphology from the aspect of crystal growth kinetics, and obtains barium sulfate products with high specific surface area, specific geometric morphology, high crystalline purity and excellent suspension stability. The method is simple, controllable in cost and environmentally friendly, and does not rely on external dispersants, which fundamentally solves the technical problems of fast settling and difficult re-dispersion of traditional blocky barium sulfate in suspension systems, and provides reliable technical support for the deep application of barium sulfate in high-end coatings, precision inks, medical contrast agents and high-performance composite materials. DETAILED DESCRIPTION

[0022] The present application provides a preparation method of suspension barium sulfate, aiming to solve the technical problems of poor suspension stability, fast settling rate and difficult re-dispersion of barium sulfate particles in the prior art due to the dense blocky morphology. To achieve the above-mentioned application purpose, the present application introduces a specific concentration of magnesium citrate as a crystal type regulator at the initial stage of barium sulfate precipitation reaction, and directionally intervenes in the crystal face growth kinetics of barium sulfate from the source of crystal nucleation and growth, thereby obtaining barium sulfate crystals with high specific surface area, specific geometric morphology (flaky or spindle-like) and optimized surface energy distribution, which significantly improves the suspension stability of barium sulfate in aqueous phase or organic medium, while maintaining its high chemical purity and crystalline integrity.

[0023] The technical solutions of the present application will be described in detail below in combination with specific examples and comparative examples, so as to ensure that those skilled in the art can fully understand and implement the present application.

[0024] Example 1: Step 1: Prepare a barium chloride aqueous solution with a concentration of 1.0 mol / L, and prepare a sodium sulfate aqueous solution with a concentration of 1.0 mol / L at the same time;

[0025] Step 2: Put the barium chloride aqueous solution into the reaction container, set the stirring rate to 500 revolutions per minute, and control the reaction system temperature to 50°C;

[0026] Step 3: Add the magnesium citrate aqueous solution with a concentration of 0.05 mol / L to the reaction system, and the amount of magnesium citrate added is 1.5% of the molar amount of barium ions in terms of magnesium ions, and the addition method is one-time injection;

[0027] Step 4: 3 minutes after the completion of the addition of magnesium citrate, add the sodium sulfate aqueous solution at a rate of 4 milliliters per minute, and continue stirring for 60 minutes after the addition is completed;

[0028] Step 5: After the reaction is completed, centrifuge the slurry at 4000 revolutions per minute for 15 minutes to separate the solid and liquid; the obtained solid is washed with deionized water for 5 times (each time after washing, centrifuge under the same conditions), and replaced with ethanol for washing 2 times; then, under the conditions of a vacuum degree of -0.095 MPa and a temperature rising rate of 2°C / min, dry at 80°C for 12 hours to obtain a flaky barium sulfate product.

[0029] Example 2: Step 1: Prepare a barium nitrate aqueous solution with a concentration of 1.5 mol / L, and at the same time, prepare a potassium sulfate aqueous solution with a concentration of 1.5 mol / L;

[0030] Step 2: Put the barium nitrate aqueous solution into the reaction container, set the stirring rate to 400 revolutions per minute, and control the reaction system temperature to 45°C;

[0031] Step 3: Add the magnesium citrate aqueous solution with a concentration of 0.08 mol / L to the reaction system, and the amount of magnesium citrate added is 2.0% of the molar amount of barium ions in terms of magnesium ions, and the addition method is uniform dropwise addition within 15 minutes;

[0032] Step 4: 4 minutes after the completion of the addition of magnesium citrate, add the potassium sulfate aqueous solution at a rate of 5 milliliters per minute, and continue stirring for 90 minutes after the addition is completed;

[0033] Step 5: After the reaction is completed, centrifuge the slurry at 4000 revolutions per minute for 15 minutes to separate the solid and liquid; the obtained solid is washed with deionized water for 5 times (each time after washing, centrifuge under the same conditions), and replaced with ethanol for washing 2 times; then, under the conditions of a vacuum degree of -0.095 MPa and a temperature rising rate of 2 / min, dry at 90 °C for 10 hours to obtain a flaky barium sulfate product.

[0034] Example 3: Step 1: Prepare a barium acetate aqueous solution with a concentration of 0.8 mol / L, and at the same time, prepare an ammonium sulfate aqueous solution with a concentration of 0.8 mol / L;

[0035] Step 2: Put the barium acetate aqueous solution into the reaction container, set the stirring rate to 600 revolutions per minute, and control the reaction system temperature to 55 ;

[0036] Step 3: Add the magnesium citrate aqueous solution with a concentration of 0.03 mol / L to the reaction system, and the amount of magnesium citrate added is 2.8% of the molar amount of barium ions in terms of magnesium ions, and the adding method is uniform dropwise adding within 20 minutes;

[0037] Step 4: 2 minutes after the completion of the addition of magnesium citrate, drop the ammonium sulfate aqueous solution at a rate of 3 milliliters per minute, and continue stirring the reaction for 120 minutes after the dropwise addition is completed;

[0038] Step 5: After the reaction is completed, centrifuge the slurry at 4000 revolutions per minute for 15 minutes to separate the solid and liquid; the obtained solid is washed with deionized water for 5 times (each washing is followed by centrifugation under the same conditions), and is replaced with ethanol for washing 2 times; then, under the conditions of a vacuum degree of -0.095 MPa and a temperature rising rate of 2 / min, the product is dried at 70 °C for 18 hours to obtain flaky barium sulfate product.

[0039] Example 4: Step 1: Prepare a barium chloride aqueous solution with a concentration of 1.2 mol / L, and at the same time, prepare a sodium sulfate aqueous solution with a concentration of 1.2 mol / L;

[0040] Step 2: Put the barium chloride aqueous solution into the reaction container, set the stirring rate to 700 revolutions per minute, and control the reaction system temperature to 70°C;

[0041] Step 3: Add the magnesium citrate aqueous solution with a concentration of 0.06 mol / L to the reaction system, and the amount of magnesium citrate added is 3.8% of the molar amount of barium ions in terms of magnesium ions, and the adding method is uniform dropwise adding within 25 minutes;

[0042] Step 4: 5 minutes after the completion of the addition of magnesium citrate, drop the sodium sulfate aqueous solution at a rate of 8 milliliters per minute, and continue stirring the reaction for 45 minutes after the dropwise addition is completed;

[0043] Step 5: After the reaction is completed, centrifuge the slurry at 4000 revolutions per minute for 15 minutes to separate the solid and liquid; the obtained solid is washed with deionized water for 5 times (each washing is followed by centrifugation under the same conditions), and is replaced with ethanol for washing 2 times; then, under the conditions of a vacuum degree of -0.095 MPa and a temperature rising rate of 2 / min, the product is dried at 100 °C for 8 hours to obtain spindle-shaped barium sulfate product.

[0044] Example 5: Step 1: Prepare a barium nitrate aqueous solution with a concentration of 1.8 mol / L, and at the same time, prepare an ammonium sulfate aqueous solution with a concentration of 1.8 mol / L;

[0045] Step 2: Place the barium nitrate aqueous solution in the reaction vessel, set the stirring rate to 500 revolutions per minute, and control the reaction system temperature at 75°C;

[0046] Step 3: Add a 0.1 mol / L magnesium citrate aqueous solution to the reaction system, with the magnesium citrate added at 4.5% of the molar amount of barium ions, and added at a uniform rate over 30 minutes;

[0047] Step 4: Three minutes after the completion of the addition of magnesium citrate, add an ammonium sulfate aqueous solution at a rate of 9 milliliters per minute, and continue stirring the reaction for 75 minutes after the addition is complete;

[0048] Step 5: After the reaction is complete, centrifuge the slurry at 4000 revolutions per minute for 15 minutes to separate the solid and liquid; wash the obtained solid with deionized water 5 times (each time after washing, centrifuge under the same conditions), and replace with ethanol for washing 2 times; then, under the conditions of a vacuum degree of -0.095 MPa and a temperature increase rate of 2 / min, dry the product at 110 °C for 6 hours to obtain a spindle-shaped barium sulfate product.

[0049] Comparative Example 1: Step 1: Prepare a 1.0 mol / L barium chloride aqueous solution, and simultaneously prepare a 1.0 mol / L sodium sulfate aqueous solution;

[0050] Step 2: Place the barium chloride aqueous solution in the reaction vessel, set the stirring rate to 500 revolutions per minute, and control the reaction system temperature at 50 °C;

[0051] Step 3: Do not add a magnesium citrate aqueous solution to the reaction system;

[0052] Step 4: Directly add the sodium sulfate aqueous solution at a rate of 4 milliliters per minute, and continue stirring the reaction for 60 minutes after the addition is complete;

[0053] Step 5: After the reaction is complete, the subsequent solid-liquid separation, washing, and drying operations are completely consistent with Example 1, and a traditional block-shaped barium sulfate product is obtained.

[0054] Comparative Example 2: Step 1: Prepare a 1.0 mol / L barium chloride aqueous solution, and simultaneously prepare a 1.0 mol / L sodium sulfate aqueous solution;

[0055] Step 2: Place the barium chloride aqueous solution in the reaction vessel, set the stirring rate to 500 revolutions per minute, and control the reaction system temperature at 50 °C;

[0056] Step 3: 0.05 mol / L magnesium citrate aqueous solution was added to the reaction system, the amount of magnesium citrate added was 0.2% of the molar amount of barium ions (lower than the range of 0.5%-5.0% of the present application), and the addition method was one-time injection;

[0057] Step 4: 3 minutes after the completion of the addition of magnesium citrate, sodium sulfate aqueous solution was added at a rate of 4 milliliters per minute, and after the addition was completed, the stirring reaction was continued for 60 minutes;

[0058] Step 5: The subsequent solid-liquid separation, washing, and drying operations were completely consistent with Example 1, and a blocky barium sulfate product was obtained.

[0059] Comparative Example 3: Step 1: A 1.0 mol / L barium chloride aqueous solution was prepared, and a 1.0 mol / L sodium sulfate aqueous solution was also prepared;

[0060] Step 2: The barium chloride aqueous solution was placed in a reaction vessel, the stirring rate was set to 500 revolutions per minute, and the temperature of the reaction system was controlled at 90 (higher than the range of 25-80 of the present application);

[0061] Step 3: 0.05 mol / L magnesium citrate aqueous solution was added to the reaction system, the amount of magnesium citrate added was 1.5% of the molar amount of barium ions, and the addition method was one-time injection;

[0062] Step 4: 3 minutes after the completion of the addition of magnesium citrate, sodium sulfate aqueous solution was added at a rate of 4 milliliters per minute, and after the addition was completed, the stirring reaction was continued for 60 minutes;

[0063] Step 5: The subsequent solid-liquid separation, washing, and drying operations were completely consistent with Example 1, and a blocky barium sulfate product containing a small amount of flaky was obtained.

[0064] Performance test method

[0065] 1. Morphology and particle size test:

[0066] The morphology of the sample was observed by scanning electron microscopy, 50 particles were randomly selected to measure the particle size (for flaky samples) or length (for spindle-shaped samples), thickness (for flaky samples), or maximum diameter (for spindle-shaped samples), and the average value and aspect ratio (flaky: particle size / thickness, spindle-shaped: length / maximum diameter) were calculated.

[0067] 2. Specific surface area test:

[0068] The adsorption-desorption isotherm of the sample was determined at liquid nitrogen temperature by nitrogen adsorption-desorption method, and the specific surface area was calculated by Brunauer-Emmett-Teller method.

[0069] 3. Suspension stability test:

[0070] Take 10 grams of sample, add 100 milliliters of deionized water, place in a stirring device to stir at a rate of 1000 revolutions per minute for 10 minutes, stop stirring and observe the settlement of the sample (whether layered, whether there is hard sediment) within 24 hours, and measure the turbidity of the supernatant after 24 hours of standing using a turbidimeter.

[0071] 4. Crystalline purity and crystallinity test:

[0072] Using X-ray diffraction method, the diffraction pattern of the sample is determined, and compared with the standard pattern No. 05-0457 of barite type barium sulfate to determine whether it is a pure phase; the crystallinity index is obtained by calculating the ratio of the main peak intensity to the background intensity.

[0073] 5. Impurity residue test:

[0074] Using inductively coupled plasma mass spectrometry, the residual amount of magnesium citrate in the sample is determined.

[0075] Performance test data comparison table:

[0076]

[0077] Examples 1-5 successfully prepared sheet-like or spindle-like barium sulfate due to strict control of the amount of magnesium citrate (1.0%-4.5%), reaction temperature (45-75 ), and sulfate drop rate (3-9 milliliters per minute) within the range defined in the present application. Such products have a much higher specific surface area (20-32 square meters per gram) than traditional blocky barium sulfate (4 square meters per gram), no layering or hard sediment within 24 hours, low supernatant turbidity (2-4 NTU), and high crystallinity index (95%-97%), low magnesium citrate residue (25-45 ppm), fully meeting the requirements of water phase and organic medium system for suspension stability and purity.

[0078] Comparative Example 1 did not add magnesium citrate, and the product was a dense block with very low specific surface area, which layered within 2 hours and formed a hard sediment within 24 hours, directly reflecting the core problem of poor suspension stability of traditional methods;

[0079] Comparative Example 2 had insufficient amount of magnesium citrate (0.2%), which could not effectively control the crystal form, and the product was blocky with low specific surface area, which layered within 8 hours, and the suspension stability was much worse than that of the examples;

[0080] Comparative Example 3 had a too high reaction temperature (90 ), which destroyed the crystal form control effect, and the product was mainly blocky, which layered within 6 hours, further proving the rationality of the reaction temperature range of the present application.

[0081] By adjusting the amount of magnesium citrate, reaction temperature, and the dropping rate of sulfate, the controllable switching between flaky and spindle-like morphologies can be realized (such as 1.0%-2.8% magnesium citrate, 40-55 flaky, 3.8%-4.5% magnesium citrate, 70-75 spindle-like), which can meet the customized needs of different application scenarios (such as coating brick-mud structure, polymer orientation enhancement), highlighting the flexibility and practicality of the process.

[0082] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing suspended barium sulfate, characterized in that, Includes the following steps: Step 1: Prepare an aqueous solution of soluble barium salt with a concentration of 0.5 mol / L to 2.0 mol / L; the soluble sulfate is selected from any one of sodium sulfate, potassium sulfate, or ammonium sulfate; at the same time, prepare an aqueous solution of soluble sulfate with a concentration of 0.5 mol / L to 2.0 mol / L, the soluble barium salt being selected from any one of barium chloride, barium nitrate, or barium acetate; Step 2: Place the soluble barium salt aqueous solution in a reaction vessel, control the temperature of the reaction system under stirring conditions, and the stirring rate is 200 rpm to 800 rpm; Step 3: Add an aqueous solution of magnesium citrate to the reaction system. The concentration of the aqueous solution of magnesium citrate is 0.01 mol / L to 0.1 mol / L. The addition method is either a one-time injection or a uniform dropwise addition over 5 to 30 minutes. Step 4: Within 5 minutes after the addition of magnesium citrate, begin adding the soluble sulfate aqueous solution dropwise to the reaction system. After the addition is complete, continue stirring the reaction for 30 to 120 minutes. Step 5: After the reaction is complete, the resulting slurry is subjected to solid-liquid separation. The obtained solid is washed with deionized water 3 to 5 times and with ethanol for replacement washing 1 to 2 times, and then at 60°C. Up to 120 The suspended barium sulfate product is obtained by drying for 6 to 24 hours. When the amount of magnesium citrate added is 1.0%-3.0% of the molar amount of barium ions, the reaction temperature is controlled at 40-60℃, the dropping rate of the sulfate solution is 3-6 mL / min, and the resulting barium sulfate crystals are regular flakes with an average particle size of 0.8-2.5 μm, a thickness of 80-200 nm, an aspect ratio of 4:1 to 10:1, and a specific surface area of ​​15-35 m². 2 / g; When the amount of magnesium citrate added is 3.5%-5.0% of the molar amount of barium ions, the reaction temperature is controlled at 65-80℃, the dropping rate of the sulfate solution is 7-10 mL / min, and the resulting barium sulfate crystals are spindle-shaped with an average length of 1.5-3.0 μm, a maximum diameter of 0.3-0.6 μm, an aspect ratio of 3:1 to 6:1, and a specific surface area of ​​12-25 m². 2 / g.

2. The method for preparing suspended barium sulfate according to claim 1, characterized in that, The solid-liquid separation is performed by centrifugation at a speed of 4000 rpm for 15 minutes; the deionized water washing is performed 5 times, and centrifugation is performed under the same conditions after each washing; the ethanol replacement washing is performed twice.

3. The method for preparing suspended barium sulfate according to claim 1, characterized in that, The drying process is carried out under vacuum conditions, with a vacuum degree of -0.095 MPa and a drying temperature of 80°C. The drying time is 12 hours, and the heating rate is 2. / min.

4. The method for preparing suspended barium sulfate according to claim 1, characterized in that, The obtained barium sulfate product is high-purity barite-type barium sulfate, and its X-ray diffraction pattern shows no impurity phase diffraction peaks, which meets the JCPDS No. 05-0457 standard.

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