Waste from silicon processing as a source of energy and raw materials

As industrial partner of ICARUS, we are working on the upscaling of new innovating solutions to make Si-kerf a sustainable secondary raw material. Different types of Si-fines received from internal and external sources will be investigated to understand the impact of the waste characteristics on the final product quality. The process is based on the reaction of free silicon contained in the waste with an alkaline hydroxide solution, under controlled temperature and pressure conditions, produces hydrogen, silicates and heat.

We have found three interesting types of waste as sources for use in our chemical conversions. All three types can be understood as chemical energy stores that can pass on part of the energy as hydrogen through our treatment, but at the same time release their energy in the form of heat through the exothermic reaction and ultimately even lead to a salable product. The characterization of such waste was necessary for the chemical studies.

First results of individual experiments in the conversion of silicon waste to water glass and hydrogen are presented and discussed.