JP4551747B2 - Production method of fine powder - Google Patents

Description

  The present invention relates to a production method for pulverizing a raw material which is a subject in many industrial fields such as fine powder, particularly pharmaceuticals, agricultural chemicals, electronic component materials, ceramics, metals, metal oxides, functional pigments, foods and the like.

  Conventionally, in many industrial fields described above, various pulverizers have been known for pulverizing, in particular, pulverizing raw materials. For the purpose of promoting this crushing, that is, making it finer, increasing its throughput, and preventing adhesion, media in mechanical, airflow (excluding jet mill) and wet (solution pulverization) media It is known to intervene. As this medium, a ball or a bead, and sometimes a rod or the like are used.

However, in a dry air flow type (flow-through type) pulverizer generally called a jet mill, the pulverized material is placed in an ultra-high-speed swirling air flow in the pulverization chamber, and pulverized by collision between the particles themselves. In principle, there is a possibility that if media is interposed, the media itself may be crushed and the inner wall of the grinding chamber may be worn. It was never done.
In connection with the present invention, the applicant investigated prior technical documents, but could not find anything that seemed to be particularly relevant to the present invention.

  The object of the present invention is to make the pulverizing action using a jet mill more efficient and prevent adhesion to the inner surface of the pulverizing chamber. Using the jet mill, in addition to coarse pulverization, intermediate pulverization, In particular, by promoting fine pulverization and ultra-fine pulverization, it is to prevent the above-described concern from occurring.

In order to solve the problem, the fine powder manufacturing method according to the present invention is a medium in which a zirconium oxide bead is used as a target raw material in a pulverization chamber in which an inner wall surface of a dry airflow pulverizer is configured or coated with zirconium oxide. In the method for producing fine powder in which the medium and the target raw material are simultaneously stirred in a reflux airflow, the above-described medium is preliminarily mixed with the target raw material and charged into the grinding chamber.

A method of manufacturing a fine powder of the present invention is characterized by beads of zirconium oxide media described above is spherical close to a true sphere tens mm~ several microns in diameter, with respect to the target material of the media The amount to be mixed is characterized by a volume of several tens of percent.

  By adopting the above-described configuration, according to the present invention, there is no generation of contamination due to the crushing of the media itself, which has been a concern in the past, and the wall surface in the crushing chamber is not damaged by wear, and the crushing material is further increased by the jet mill. Can be promoted, i.e., more finely, increasing the processing amount, preventing adhesion, and enabling processing in a short time.

  In the present invention, it is assumed that zirconium oxide (zirconia) is employed as a medium to be used. Zirconium oxide is used as a material for refractory materials, crucibles or special porcelain, and is excellent in impact resistance and heat resistance. It will not be damaged by a collision or the like.

  This was implemented as in the embodiment described later.

  Next, a preferred embodiment of the present invention will be described. First, in carrying out the method for producing fine powder according to the present invention, the dry-type airflow pulverizer (jet mill) to be prepared may be a known one and requires a special structure, mechanism, attached member, etc. However, it is preferable as an impact resistance that the inner wall surface of the crushing chamber is composed or covered with zirconium oxide.

  In the pulverization chamber of the above-described dry airflow pulverizer, the medium is put on the super-high-speed swirling air flow together with the target raw material (crushed material), and the pulverization of the target raw material (crushed material) is promoted.

  Here, as a medium used for carrying out the present invention, beads made of zirconium oxide (zirconia) are particularly preferable. Further, the zirconium oxide beads have a diameter of several tens to several microns, particularly about 0.05 mm, and preferably have a spherical shape close to a true sphere. The sliding surface on the surface of the sphere increases more than the hit rate, and wear and damage due to crushing of the media itself and collision with the inner wall of the crushing chamber can be avoided, and the diameter size is the degree of crushing of the crushing material. It will be easier to deal with.

  The amount of the medium crushed is different depending on the pulverized material and the degree of pulverization, but the volume is about several tens of percent.

  In addition, the media can be added to the pulverization chamber in a state of being mixed with the pulverized material in advance, or separately from the pulverized material, and the order of the input can be freely selected according to the type and purpose of the pulverized material. It is possible to select, and when the charging is performed separately, whether the charging port is common or separate can be freely selected in terms of design.

The method for producing fine powder according to the present invention is configured as described above, and further improves the efficiency of the dry airflow type pulverizer than before, but in addition to this, a classification mechanism is added and pulverized. It is also possible to sort the pulverized product for each particle size, and it is possible to design a seal air supply mechanism and the like that are necessary at that time. Of course, it is natural that various classifiers can be used for recovery of the pulverized product (separation and recovery of the pulverized product and media).

Claims (3)

Fine powder in which a media consisting of zirconium oxide beads is added to the target raw material and the media and the target raw material are simultaneously placed in a circulating airflow and stirred in a grinding chamber where the inner wall of the dry airflow type pulverizer is made of or covered with zirconium oxide. In this manufacturing method, the above-mentioned medium is put into the pulverization chamber in a mixed state with the target raw material in advance, and the method for manufacturing fine powder,   2. The method for producing fine powder according to claim 1, wherein the bead of zirconium oxide as the medium has a diameter of several tens mm to several microns and is nearly spherical.   3. The method for producing fine powder according to claim 1, wherein the volume mixed with the target raw material of the media is set to several tens of percent as a volume.