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Cryogenic conditioning process for the full recovery of multilayer artifacts

PhotovoltaicThermo-mechanical cryogenic delamination

Introduction

The purpose of the invention is to provide a process for the recovery of the raw material from multilayer artifacts. The invention consists of a controlled cryogenic thermomechanical delamination process for the recovery of a fine life of the raw material used in the production of multilayer artifacts, composed of various layers of rigid material, interspersed with materials having different thermal and elastic characteristics.

Technical features

Much of electronic and electrical waste can be subjected to the process of the invention. This invention focuses on photovoltaic panels, consisting of a back layer of waterproof polymer coating, a pair of polymer layers that protect the photovoltaic cell, and a rigid front layer of tempered glass. Current processes have a number of drawbacks, e.g. high energy consumption, only partial recovery of photovoltaic cells and protective glass, and a need for additional processes, costly from an economic and environmental point of view. This process allows a total recovery of the layers, minimizing mechanical and chemical deterioration (reducing the need for subsequent treatments). Moreover, the process described in the invention allows for almost immediate reuse of the components and materials, thus lengthening the useful life of the components themselves and not requiring further treatment; it relates to a more sustainable methodology with therefore lower economic and environmental impact compared to the processes currently known. The process involves the following steps: (i) temperature stabilization and homogenization of the artefact; (ii) a period of swift or super swift cooling of the layers adjacent to the semiconductor material layer; (iii-a) thermal cycles (for example based on Joule heating effect) imposed upon the semiconductor material layer, as to produce a thermal differential,; (iii-b) eventually, cycles of bending stresses in phase with the thermal cycles; (iv) introduction of a mixture of liquids between layers that are delaminating (artificially induced aging mechanism); (v) a mechanical separation phase of one or more external layers.

Possible Applications

  • Electric & electronic waste;
  • Photovoltaic modules;
  • Recycling companies;
  • Waste disposal / treatment plants.

Advantages

  • Full recover with less energy consumption;
  • No need of additional processing;
  • Recover of raw material minimizing mechanical or chemical deterioration;
  • Immediate reuse of the components and materials recovered;
  • Lower economic and environmental impact.