Chemical Recycle Turn turns silicone into pure building blocks and promising infinite reuse

Research conducted by CNRS researchers explains new ways to recycle silicon waste (caulking, sealants, gels, adhesives, cosmetics, etc.). It could significantly reduce the environmental impact of the sector.

This is the first universal recycling process that returns all kinds of spent silicon materials to their previous state in a life cycle where each molecule is only one silicon atom. Additionally, the raw materials currently used to design new silicones are not required. Furthermore, it is a chemical and not mechanical recycling, so reuse of materials can be performed infinitely.

Related research is published in Science.

The raw material used to make silicone is naturally produced quartz. Its components are decomposed to obtain pure silicon using high temperature metallurgy. It then reacts with methyl chloride to form chlorosilane, a molecule essential for all silicon-based polymers.

These first two transformations are highly energy-intensive, the main greenhouse gases that emit CO2 and cause climate change.

As a result, this new recycling technology will allow us to avoid one of the most harmful effects of the silicon sector. Furthermore, this chemical recycling process provides direct access to (methyl)chlorosilane, which can be industrially separated and purified, ensuring the quality of the silicon material from recycling and can be done infinitely without losing its properties.

At a time when key chemical elements and associated mineral resources are increasingly demanded, such recycling processes pave the way for mitigating potential tensions around critical quartz resources, and the resulting silicon is one of the key components used in the electronics industry.

Along with scientific and industrial partners, the author continues his research and proposes improved processes for industrial application and recycling methods for other stages of silicon treatment. Finally, they are also working on recycling other materials, making their use more sustainable.