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CN-122010159-A - Production method of anhydrous barium chloride

CN122010159ACN 122010159 ACN122010159 ACN 122010159ACN-122010159-A

Abstract

The invention belongs to the technical field of barium compound preparation, and discloses a production method of anhydrous barium chloride, which comprises the steps of dissolving a crude barium chloride dihydrate product in a mixed solvent of lower aliphatic alcohol and water for recrystallization to obtain precursor crystals with high porosity and regular morphology; and then carrying out gradient heating dehydration through the fluidized bed under the protection of vacuum or inert gas. The recrystallization, solid-liquid separation, pre-drying and fluidized bed dehydration units can be integrated in a closed pipeline system, so that automatic conveying of materials and on-line monitoring of technological parameters are realized, the intermediate products are prevented from being exposed to ambient moisture, and the cleanliness and consistency of the whole process are ensured. The fluidized bed dryer can be designed into a multi-chamber serial structure, and the fluidized bed dryer corresponds to different temperature areas for dehydration respectively, so that real continuous feeding and discharging are realized, and the requirement of industrial scale is met.

Inventors

  • LIN FUPING

Assignees

  • 宜昌华昊新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. A method for producing anhydrous barium chloride, comprising the steps of: S1, dissolving an industrial grade barium chloride dihydrate crude product into a mixed solvent consisting of lower fatty alcohol and deionized water according to the volume ratio of 3:1-7:1 to form a saturated or nearly saturated solution; S2, performing temperature control cooling crystallization on the solution to obtain crystal-modified barium chloride dihydrate crystals; S3, after solid-liquid separation, washing and low-temperature pre-drying of the obtained crystals, sending the crystals into a fluidized bed dryer; S4, carrying out gradient heating dehydration treatment on the crystal in a fluidized state under the vacuum degree of 5-50 kPa or inert gas atmosphere to obtain an anhydrous barium chloride product.
  2. 2. The method for producing anhydrous barium chloride according to claim 1, wherein the lower aliphatic alcohol is any one of methanol, ethanol, and isopropanol.
  3. 3. The method for producing anhydrous barium chloride according to claim 1, wherein an air distribution plate is arranged in the fluidized bed dryer, the aperture ratio of the air distribution plate is 5% to 10%, and the aperture diameter is 1 to 3 mm.
  4. 4. The method for producing anhydrous barium chloride according to claim 1, wherein the dehydration treatment process adopts a three-stage gradient heating program, wherein the temperature is raised to 100 ℃ in the first stage and kept at the same temperature for 30 minutes, the temperature is raised to 180 ℃ in the second stage and kept at the same temperature for 60 to 120 minutes, and the temperature is raised to 220 ℃ in the third stage and kept at the same temperature for 30 minutes.
  5. 5. The method for producing anhydrous barium chloride according to claim 1, wherein the volume ratio of the lower aliphatic alcohol to deionized water in the mixed solvent is 5:1.
  6. 6. The method for producing anhydrous barium chloride according to claim 1, wherein the solid-liquid separation is performed by centrifugation or suction filtration, the wet crystals obtained by separation are washed 1 to 2 times with an alcohol-water mixed solvent having the same composition as that used for recrystallization, the amount of the washing liquid is 0.5 to 1 time the mass of the wet crystals each time, and the washing temperature is 10 to 20 ℃.
  7. 7. The method for producing anhydrous barium chloride according to claim 1, wherein the system vacuum degree is 20kPa in the vacuum dehydration mode, and the system maintains a micro positive pressure of 101.3 to 105kPa in the inert gas protection mode.
  8. 8. The method for producing anhydrous barium chloride according to claim 1, wherein in the gradient temperature-raising program, the temperature-raising rate in the first stage is 2 to 5 ℃ per minute, the temperature-raising rate in the second stage is 1 to 3 ℃ per minute, and the temperature-raising rate in the third stage is 1 ℃ per minute.
  9. 9. The method for producing anhydrous barium chloride according to claim 1, wherein the temperature of the bed layer is monitored in real time by a multi-point thermocouple during the dehydration treatment, the temperature difference of each measuring point is less than +/-3 ℃, the inter-particle collision frequency is 5 to 15 times per second, and the average collision kinetic energy is 0.8 to 1.5 millijoules.
  10. 10. The method for producing anhydrous barium chloride according to claim 1, wherein after dehydration, the product is cooled to below 50 ℃ at a rate of 1 to 3 ℃ per minute under inert atmosphere or vacuum conditions and discharged, and a double valve isolation system is arranged at the discharge port.

Description

Production method of anhydrous barium chloride Technical Field The invention belongs to the technical field of barium compound preparation, and relates to a production method of anhydrous barium chloride. Background The anhydrous barium chloride is used as an important inorganic chemical raw material, is widely applied to the fields of electronic ceramics, optical glass, pigment manufacturing, metal heat treatment and the like, and the purity, the particle morphology and the chemical activity of the anhydrous barium chloride directly determine the performance stability and the process suitability of the end product. In industrial production, anhydrous barium chloride is usually prepared by thermal dehydration of barium chloride dihydrate, and the route is dominant for a long time due to readily available raw materials and mature process. The traditional dehydration process adopts a rotary kiln, a box type oven or a static heating furnace, and carries out step heating treatment on the barium chloride dihydrate under the condition of normal pressure or micro negative pressure so as to gradually expel crystal water. The method effectively solves the basic requirement of converting the hydrate into the anhydrous substance in the early industrialization stage, and particularly shows certain economical efficiency and operability in a rough application scene with low requirements on the physical form of the product. However, barium chloride dihydrate crystals release crystal water in the crystal lattice in a non-uniform and synchronous manner during heating, and violent desorption occurs in a specific temperature range. If the heating rate is controlled improperly or the heat transfer is uneven, a significant temperature gradient is easily formed inside the material, resulting in instantaneous overheating of the local area. Under this condition, the surface of the crystal is rapidly dehydrated to form a compact water-free layer, and water remains in the crystal, so that the generated vapor pressure difference not only promotes fusion sintering among particles, but also induces lattice reconstruction to form a hard aggregate. The specific surface area of the sintered product is reduced, the surface active site is reduced, and the internal micropore structure collapses, so that irreversible hardening is very easy to occur due to micro-moisture adsorption in the subsequent storage or use process, and the fluidity, the dispersibility and the reactivity of the product are seriously affected. The problem is based on the coupling effect of multiple factors such as single heat conduction path among particles, large gas phase mass transfer resistance in a static heating mode, difficulty in maintaining dynamic balance of a solid-gas interface in a dehydration process and the like. Disclosure of Invention In order to achieve the aim of the invention, the invention provides a production method of anhydrous barium chloride, which is characterized in that the method is used for carrying out recrystallization pretreatment under a specific solvent system on a crude product of the anhydrous barium chloride before dehydration, and realizing the cooperative regulation and control on the microstructure, the particle morphology and the chemical activity of a final anhydrous barium chloride product by combining a fluidized bed dehydration process under the vacuum or inert gas protection condition, thereby obtaining the anhydrous barium chloride powder with high purity, high specific surface area, excellent fluidity and hardening resistance. The method comprises the steps of firstly dissolving an industrial grade barium chloride dihydrate crude product in a mixed solvent consisting of low-grade fatty alcohol and deionized water according to a volume ratio of 3:1-7:1 to form a saturated or nearly saturated solution, secondly carrying out temperature control cooling crystallization on the solution to obtain crystal modified barium chloride dihydrate crystals, thirdly carrying out solid-liquid separation, washing and low-temperature predrying on the obtained crystals, then sending the crystals into a fluidized bed dryer, and finally carrying out gradient heating dehydration treatment on the crystals in a fluidized state under the vacuum degree of 5-50 kPa or inert gas atmosphere to obtain anhydrous barium chloride products. In the recrystallization step, the lower aliphatic alcohol is any one of methanol, ethanol or isopropanol, and the purity is not lower than 99.5%. In the mixed solvent, the volume ratio of the lower aliphatic alcohol to the deionized water is preferably 5:1. The dissolution operation was performed at 40 to 60 ℃ with stirring rates of 150 to 300 revolutions per minute and dissolution times of 30 to 60 minutes to ensure complete dissolution of barium chloride dihydrate and formation of a uniform transparent solution. Subsequently, the solution is cooled to 5 to 15 ℃ at a rate of 0.5 to 2 ℃ per minute and seeded at the con