[Pretreatment] [Dissolution] [Separation] [Precipitation] [Drying] [Solvent Recovery]

In pretreatment, the waste is turned into raw material suitable to be fed into the Vinyloop®.

Dissolution: in a closed reactor, the waste is combined with a selective solvent that releases the PVC compound matrix. All the additives and foreign materials are either dissolved or are in suspension in the liquid.

Separation: the solution is filtered. The non-dissolved fraction is separated.

Precipitation: the addition of steam converts the organic phase into an aqueous one. The PVC resin precipitates and captures the constituents of the compound in PVC compound microgranules.

Drying: the water is extracted from the slurry.

Solvent recovery: the solvent is re-used in a closed loop.

Pretreatment is a set of physical operations which turn the waste into raw material suitable to be fed into the Vinyloop®. The need for these operations and their sequence depend on the waste's composition. These physical operations may include: a cleaning step (washing, etc.), reducing the size for fast dissolution  (by cutting, grinding, milling, etc.) and a homogenization step.
Dissolution is carried out using a solvent that selectively dissolves the PVC compound and not the secondary material.It is carried out at a temperature which is adapted to the material and its composition, always in the absence of air in a closed process.
For separation, the nature of the insolubles will determine the technique required, such as centrifuging, decanting, cycloning, because the behavior of fibers from coated fabric differs from that of rubber in waste from cables, for instance. After separation, the secondary material is:washed with pure hot solvent to eliminate virtually all of the dissolved PVC compound, stripped with steam to recover all the solvent then discharged.
At the precipitation stage, additives can be added. This is a specific feature of this recycling process and allows the properties of the output to be adjusted. At Vinyloop Ferrara SpA, a plasticizer is added to adjust the shore hardness. Steam is injected to evaporate the solvent completely.The PVC compound formulation is recovered as an aqueous slurry. All the components of the original PVC resin formulation are recovered in the regenerated compound, not just PVC (except in very special cases or in voluntarily designed separation).
The slurry from the precipitation (which is a mixture of process water and Regenerated PVC compound) is dried. The process water is treated to reach the required purity before discharge. The Regenerated PVC compound is packed and ready for use.
The solvent runs in a closed loop. Over 99.9% of the solvent is recovered and separated from the water in a multi-step process using condensation and density separation. A final gas effluent treatment lowers the solvent concentration in the flue gas to meet legal requirements.