- Turn-key: mixed plastic sorting plant & HDPE washing plant from a single source
- Demetallization line for ferrous and non-ferrous metals
- Friction washer as heart of the washing line
The Italian AMUT Group has recently supplied a complete recycling plant to a customer in the UK for the recycling of HDPE, PP and other thermoplastic materials. The customer chose AMUT not only for technological reasons, but also because he could buy a turn-key mixed plastic sorting plant and HDPE washing plant from a single source. AMUT is in a position to cover the entire recycling flow from mixed plastics sorting up to the delivery of flakes which can be reused in further processes such as extrusion, injection moulding or thermoforming. The recycling plant reclaims polyolefin thermoplastic scrap with an output of 10 tons per hour.
Rotary drum separates material into three different streams
The plant is fed by mixed plastics materials packed into bales. A forklift loads the bales on the extracting conveyor, which are then conveyed to the “bales breaker machine”, designed to break up bales mainly composed of plastic materials. This machine does not shred material but gets back bulk material in order to feed the recovery plant in a constant and regular way. Breaking up of the bales is done by the circular motion of a drum equipped with fixed teeth. The rotor’s sharp tools enter and separate the material. The material falls on a conveyor belt below and and is conveyed to the pre-sorting picking station where pickers take away bulky materials, such as cardboard and film, from the stream. After this first selection, the material is conveyed to the rotary drum, where the separation depends on size. Three different streams are possible:
1. Material smaller than 30 mm falls on a conveyor belt, and is jointly conveyed with the stream coming from the ballistic separators, to the residue storing unit.
2. Material between 30 and 260 mm is conveyed to the ballistic separator where the hard materials are separated from the light and flat ones by means of paddles. In addition, due to the grids installed on the paddles, fine material not yet separated by the rotary drum, is evacuated and conveyed to a special storing unit. Flat and light material is conveyed upwards by a conveyor. Hard materials, sorted by a ballistic separator, are conveyed to station where plastic material is automatically selected by optical readers.
3. Material larger than 260 mm is conveyed to the bulky materials picking line, where different types of materials, such as plastic films, are manually selected and discharged in chutes. After a NIR optical scanning, the material is conveyed to the QC (quality control) stations, where pickers recycle errors, conveyed at the beginning of the automatic line.
Demetallization line for ferrous and non-ferrous metals
Before entering the automatic line, the “hard material” stream passes through a demetallization line, consisting of an overhead band magnetic separator used for ferrous materials and an Eddy Current System used for non-ferrous metals. Ferrous and no-ferrous materials selected in the demetallization line, are weighed and then discharged into hook-lift containers.
Intensive friction of the rotary paddles generates main washing action
The main washing action is realized by rotary paddles which generate intensive friction among the flakes. Even if continuously fed, the friction washer allows an adjustment of the material retention time. A main feature of this unit is its low noise level, a soundproof box is therefore not required. The water with paper pollutants, coming from the friction washer, is filtered and then used again for the process.
After this strong washing action, the rinsing cycle starts in two troughs in series where also a separation of light pollutants (paper, non-polyolefin thermoplastics, among others) takes place. These rinsing troughs are also equipped with an automatic extractor for decanted materials and heavy plastics. This mixed plastics are dried by a centrifuge and stored in big bags. The washing section operates fully automated. The equipment allows both separation and complete cleaning of thermoplastic materials from all pollutants having specific weight higher than the thermoplastics. Possible residues of pollutants, not extracted in the washing section, are filtered later during the granulating process.