Grinding (Crushing) of Fluoroplastics

Fluoroplastic – is the general name of fluorine-containing polymers. According to the existing classification, substances of this class include:

  • polytetrafluoroethylene;
  • polytrifluorochloroethylene;
  • polyvinylidene fluoride;
  • copolymers of fluorinated ethylene.

Fluoroplastics have an excellent chemical inertness towards corrosive media. The exceptions are molten alkali metals and chlorine trifluoride.

Fields of Application of Fluoroplastics

Due to its physical and chemical properties fluoroplastics are widely used in industry, medicine, transportation, energetics, and also for solving military tasks.

Chemical inertness towards corrosive media promotes the use of fluoroplastics as structural materials for chemical instrumentation. Also, they are useful for manufacturing pipes and vessels intended for pumping and storage of highly aggressive liquids.

Fluoroplastics are characterized by a low friction coefficient, which allows to widely use this construction material in mechanical engineering. For example, fluoroplastics in friction assemblies improve the reliability and durability of industrial machinery by being able to operate even in aggressive environments, cryogenic temperatures and high vacuum.

At the same time fluoropolymers have good dielectric properties and high heat resistance. Due to this, they are used in electrical and radio engineering for insulating cables, wires and connectors, producing printed circuit boards, as well as slot insulation of electrical machines. To obtain high-quality secondary products from waste fluoroplastics, it is necessary to crush the feedstock to a particle size less than 200 microns.

Methods of Grinding of Fluoroplastics

The mechanical method of grinding is based on the use of impact mills. In this case, material of the required size is obtained by sequential application of static and dynamic loads, thereby creating stresses in the material, which excess the internal cohesive forces between the particles. Dynamic impacts, such as a stroke, are more suitable for fluoroplastics.

The complete grinding process of waste fluoroplastics is as follows:

  1. coarse crushing to a particle size of not more than 3-5 mm;
  2. additional processing of the material obtained after the first stage in order to give it the required brittleness;
  3. grinding to a particle size of not more than 200 microns;
  4. screening of the ground fluoroplastic for selecting a certain fraction (if necessary).

Grinding of Fluoroplastics in Vortex Layer Device

GlobeCore suggests using vortex layer apparatuses to intensify the process of grinding fluoroplastics. The principle of operation of this equipment is based on converting the energy of an electromagnetic field into other forms of energy directly in the area of processing. The vortex layer device consists of the working chamber with a diameter of 60-330 mm, and the inductor of rotating electromagnetic field. In the working chamber there are cylindrical ferromagnetic elements of the required diameter and length. Depending on the volume of the working chamber the number of such particles can range from a few dozens to a several thousands of pieces. Under the influence of rotating electromagnetic field the ferromagnetic elements begin to rotate in the working chamber and form a so-called “vortex layer”.

By using the vortex layer device for grinding fluoroplastics you are able to obtain the required particle size for significantly less time than when using alternative approaches. This result is achieved through a number of effects that take place in the working chamber of the machine, such as:

  • intensive dispersion;
  • acoustic and electromagnetic treatment;
  • high local pressure, and other.
обновлено: August 11, 2016 автором: dannik