Method for preparing porous ceramic microspheres with different pore structures and spraying and freezing device

A technology of porous ceramics and pore structure, applied in the field of ceramic materials, can solve the problems of uneven distribution of porous particle size and poor controllability of porous structure, and achieve the effect of enhancing controllability

Active Publication Date: 2013-11-27
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at the defect that the size distribution of porous particles prepared by the spray drying method in the prior art is not uniform, and the controllability of the porous structure is poor. A method for porous ceramic microspheres with high thickness and controllable pore structure, which is applicable to a wide range of material systems and can be industrially produced

Method used

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  • Method for preparing porous ceramic microspheres with different pore structures and spraying and freezing device
  • Method for preparing porous ceramic microspheres with different pore structures and spraying and freezing device
  • Method for preparing porous ceramic microspheres with different pore structures and spraying and freezing device

Examples

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Effect test

Embodiment 1

[0046] The method of freezing the slurry in the spray freezing device: install a baffle (a, b, c or d) between the two concentric cylinders (8, 9) of the cylindrical liquid nitrogen container (7) of the freezing device, and then A certain amount of liquid nitrogen is filled between two concentric cylinders (8, 9), so that the liquid nitrogen is distributed along the circumference of the cylinder and separated by baffles (a, b, c or d) into several parts , after covering the cover (1) on the top of the concentric cylinder (8, 9), replace the screen (3) according to the required size of the ceramic particles, then adjust the height of the sprayer to spray the slurry, and the slurry droplets pass through the cover (1) The circular hole in the middle enters the annular temperature field provided by the cylindrical liquid nitrogen container in the freezing device for freezing, and the obtained particles fall to the bottom of the small radius cylinder (8), and after being selected by...

Embodiment 2

[0048] 1) Mix alumina powder (particle size about 0.3μm) and deionized water at a mass ratio of 1:15, ball mill for 24 hours, and then add 1wt.% PVA aqueous solution (1wt.% of the total mass of the slurry) , and then ball milled for 1h, and prepared into a slurry with a solid phase content of 6.2wt.%.

[0049] 2) The above-prepared slurries with different solid phase contents are sprayed into a temperature field with a distribution of temperature and longitudinal height in a wave-like downward curve toward the bottom of the inner cylinder through a simple spray device to freeze, then collect the microspheres, and Freeze-dry for 24 hours under the condition of -55°C and 10Pa air pressure, among which, the spray height is 160mm, the amount of liquid nitrogen provided is 600mL, and several horizontal circular baffles are used in the liquid nitrogen container; 4 horizontal baffles are used The plate divides the inner cylinder into five areas of equal volume and does not interfere ...

Embodiment 3

[0052] 1) Mix hydroxyapatite powder (particle size about 0.3 μm) with deionized water at a mass ratio of 1:20, ball mill for 24 hours, and then add 1.5wt.% PVA aqueous solution (1wt of the total mass of the slurry .%), and then ball milled for 1h to prepare a slurry with a solid content of 5wt.%.

[0053] 2) Spray the above-prepared slurries with different solid content through a simple spray device into a temperature field with a distribution of temperature and longitudinal height in a wave-like downward curve toward the bottom of the inner cylinder for freezing, and then collect the frozen particles. The balls were freeze-dried for 24 hours at -45°C and the air pressure was 10Pa. The spray height was 270mm, and the amount of liquid nitrogen provided was 1120mL. Several horizontal circular baffles were used in the liquid nitrogen container. Four transverse baffles are used to divide the inner cylinder into five areas of equal volume and do not interfere with each other, and t...

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Abstract

The invention discloses a method for preparing porous ceramic microspheres with different pore structures and a spraying and freezing device. The method comprises the following steps: preparing ceramic slurry at first; spraying the slurry in a controllable ring-shaped temperature field to be frozen, collecting the frozen particles to freeze and dry, rising the temperature to degrease, rising the temperature again to sinter to obtain a porous ceramic microsphere with a pore structure, and controlling the ring-shaped temperature field to obtain porous ceramic microspheres with different pore structures. The spraying and freezing device comprises a sprayer and a freezing device, wherein the freezing device takes a cylindrical liquid nitrogen container as the main body; the cylindrical liquid nitrogen container comprises a large-diameter cylinder and a small-diameter cylinder, which are concentric; the area between the large-diameter cylinder and the small-diameter cylinder is closed; a plurality of baffles are arranged in the area between the large-diameter cylinder and the small-diameter cylinder. The method is simple to operate, and the porous ceramic microspheres with uniform sizes, high degrees of sphericity and controllable pore structures can be prepared through the method, and the device has a simple structure, is strong in practicability, and can control the pore structures of the porous ceramic microspheres through controlling the temperature field.

Description

technical field [0001] The invention relates to a method for preparing porous ceramic microspheres with different pore structures and a spray freezing device, belonging to the field of ceramic materials. Background technique [0002] Due to its special structure, porous microspheres have the characteristics of large specific surface area and low density. They have a wide range of applications in the fields of medicine and material science, and can be used as catalysts and drug carriers. The particle size distribution of microspheres and their internal porous structure directly affect the porosity and other properties of the particles. Therefore, preparing microspheres with desired particle size and porous structure is one of the key technologies for preparing porous microspheres. [0003] At present, because the layered porous structure in microspheres can guide the differentiation or growth of stem cells as a 3D scaffold, scholars at home and abroad have aroused an upsurge...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/00
CPCC04B35/1115B28B1/004B28B1/007C04B35/447C04B35/46C04B35/486C04B35/62655C04B35/62675C04B35/6268C04B35/638C04B38/009C04B2235/528C04B35/00
Inventor 张斗余敏周科朝张妍
Owner CENT SOUTH UNIV
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