Recycling Process

Step 1 – Collection of Bottles

The first step in PET recycling is the collection of bottles. A large portion of collection is done via "open-market" recycling where the rag-pickers pick-up the PET bottles and sell them to collection centers.

Once collected and sorted at these centers, the plastic bottles are baled into large compacted bundles (pictured below) and sent to a local PET bottle washing plant for processing into "hot-washed" PET flakes.

Step 2 – De-baling & Sieving

When the plastic bottles arrive at a PET recycling / washing plant, they are usually in large bales that have already been separated by color. The main goal is to recover these dirty plastic bottles and thoroughly clean them so they can be reused. At the same time, various contaminants must also be separated such as the plastic labels wrapped around each bottle and the bottle caps which are not made from PET.

For a standard, fully automated PET washing line, the first piece of equipment is a "de-baling machine" that takes large, compacted bales of PET bottles and breaks them loose so the bottles flow freely onto a belt conveyor which leads to a large trommel / Sieving machine.

The trommel, a large rotating tunnel with holes smaller than the standard PET bottle, is a robust piece of machinery for removing small contaminants from the material stream. It's likely for the bales to contain various small contaminants such as broken glass, metals, rocks, paper/cardboard, etc. These small contaminants fall through the holes on the trommel while PET bottles move forward in the washing line in a steady flow.

Step 3 – Pre-sorting & Label Separation

An accurate way to remove contaminants from the material stream is via manual sorting. For instance, a milk bottle (made of HDPE) would have made it pass the trommel process, however, this is considered a contaminant since it's not PET. The material stream enters long rows of belt conveyors where attendants standing on both sides of the conveyor pluck out contaminants manually.

From here the sorted bottles are conveyed into the label scrapper. Heat shrink labels of PET bottles can't be removed through bottle pre-washing Hence in the label scrapper bottle surface is scrapped and labels are removed off the bottles. Then the bottles and labels are separated using adjustable wind force.

Step 4 – Bottle Pre-washing

Using automated circulation and continuous feeding, high temperature chemical water is supplied to wash PET bottles. This ensures removal of labels, dirt, glue, metal, rubber and other impurities on bottle surfaces. High temperature washing can make changes in the appearance of PVC bottles, making it easily distinguishable from PET bottles and therefore simplifying the manual sorting process.

Step 5 – Manual Sorting

Pre-washed bottles are then placed on widened long belts where attendants manually remove PVC, PC bottles, bottles with metal caps, HDPE bottles and other degraded bottles which are not fit for reuse. Only first grade PET bottles are allowed to enter the grinder for further process.

Step 6 & 7 – Wet Grinding & Hot Washing

The most efficient way of converting PET bottles into flakes is the wet grinding. The granulator is used as a washing machine. Due to the mechanical action during the cutting process, there is friction in the cutting chamber of the granulator. Hence there is an excellent opportunity of adding water and using it for washing during the size reduction process. The result is always convincing as the left over impurities on the inner bottle surface are completely removed during wet grinding.

Step 8 – Rinsing & Drying

The flakes coming out of the turbo washer and its centrifuge still contain a lot of residual water, caustic soda and detergent. To remove this residues the flakes need careful rinsing in fresh water. The hot water with caustic soda needs its own, separate water circuit. The glue has to be removed from the water, the fines have to be taken out, the refill of caustic soda and detergents has to be done.

To ensure the cleanliness and transparency of the PET flakes, high speed machinery is used for centrifugal dewatering the reduce the moisture levels to 1 ~ 2%.

Step 9 – Fines & Dust Removal

It has been established that during PET flakes manufacturing, PET dust, also known as PET fines are produced. These fines have a significant impact on the next production, especially the production process of PET films and sheets.

With the help of our fines-removal equipment which also incorporates hot air blowing, small plastic/paper wrappers and fines can be effectively removed from the PET flakes.

Step 10 – Metal Removal & Final Sorting

Hot-washed PET flakes are then passed through our "VINSYST" all metal separator machine which removes all ferrous and non-ferrous particles (if any) from the PET flakes.

After this before final packing again PET flakes are manually sorted to ensure that contaminant particles are removed and then are forwarded for final packing.

Step 11 – Packing

Thoroughly sorted PET flakes are then automatically packed into Jumbo bags having capacity 450kgs and are stacked for final dispatch to our customers.