Size reduction of waste plastic 2

Densification process

Plastic wastes which are coming as packaging films, fibers and foams have lower density. So previously mentioned cutting or crushing methods can’t use for those wastes to size reduction. Because of the lower density many problems can arise while transporting, conveying, and feeding. In this method density is increased by using agglomeration process.

Generally there are three main methods are used to do agglomeration by densifying disks, by compression, and by agitation.  

 

densifying disks

• Densifying disks

Mostly films which are made up from PP, LDPE, HDPE and fibres made from polyamides are converting in to granulate form using this method. In here plastic is slightly heated by friction disks and densification is happen without happening thermal degradation.

• By compression

In this method compression is used to extrude plastic and form pellets continuously. Compressed material is coming out through a die and it is chopped using a rotary cutter.  

• By agitation

In this method waste plastic is vigorously agitated causing the plastic material to agglomerate in to densified particles. This is happening because high shear generated by rotating blades brings plastic to a near melting state.

Advantages of densification are reduced storage volume, reduced the transporting cost, improved flow properties etc.   

  

Pulverization processes

pulverization mill

Pulverization mills like disk mills and pin mills are used in this method for converting plastic waste in to fine powder. Recycle polymer powders including sintered powder coatings, molding powders, fillers are produced using this method.  

Mainly this method is used for size reduction of PVC. After pulverization that powder has high bulk density, excellent flow characteristics, and homogeneous composition.