Plastic Recycling
Plastics are divided into three main groups. These are the groups of thermoplastics, thermosets and elastomers. Of these three groups, only the thermoplastics can be processed by melting several times, so that the material or raw material recycling focuses on this group of plastics.
Depending on the area in which the plastic waste occurs and the degree of contamination, the intensity of the treatment process is adjusted accordingly.
Basically, there is a processing process of plastic waste from the steps of crushing, classifying, sorting, melting and cooling.
During the crushing process and the subsequent classification, the plastic waste is reduced to a grain size that allows a subsequent melting process. It need to be considered that both, mono-fraction plastic and mixed or contaminated plastics, e.g. various types of plastic or mixed with wood, metal and / or paper accrues. During classification and through the use of sieves with different opening sizes, the first separation of different materials takes place in which a part of the foreign substances can also be removed. The removal of the foreign substance metal occurs through the use of magnetic tapes, partly with the support of metal detectors.
Since the mixture of various plastics can significantly degrades the quality of the end-product, an efficient separation of the plastic waste is necessary. This is done during the sorting process by using the own density or conductivity of the processed grinding stock. Particularly suitable for this purpose is the floating-sink method, in which the material to be ground is passed through industrial tanks with liquid. Depending on the density of the liquid the processed materials floats or sinks as a function of its own density. In case there is certainty in terms of the origin of the raw material and the material mixture of the plastic waste, the sorting process can be neglected as long as the quality of the finished secondary plastic meets the requirements of the later intended use.
The next step is granulation or extrusion. In both processes, the separated plastic is heated until it melts. The quality of the material can be influenced by the addition of various additives, whereby both the flow properties and the impact resistance can be improved. This process is enormously important as the qualitative requirements of secondary plastics are similar to those of the primary plastics in order to ensure a trouble-free production of the plastic processing companies and to protect the machines and tools used from a damage. The last steps of the plastic recycling are cooling and reduction of the material to the desired core size. We support you during the planning and the implementation of recycling projects.
