Scientists from Tomsk Polytechnic University and Sevastopol State University have developed a two-stage method for recycling end-of-life solar panels to produce silicon carbide, a valuable material used in power electronics, ceramics and other industrial applications. This was reported on the website of the Ministry of Science and Higher Education of the Russian Federation.
Photovoltaic modules typically operate for 20–30 years before reaching the end of their service life. They contain multiple materials, including glass, aluminium, silicon, copper and polymers, making their recycling a complex process. The new method enables the recovery of silicon-containing materials and their conversion into silicon carbide, which is valued for its hardness, heat resistance, corrosion resistance and high thermal conductivity.
To test the technology, the researchers processed a used polycrystalline solar panel. First, they applied pyrolysis at 500°C to separate silicon from the polymer layer. The resulting silicon-containing material was then mixed with technical carbon and treated using a non-vacuum electric arc at 1,800°C. This produced silicon carbide in just one minute.
According to Zhanar Bolatova, one of the study’s authors and an assistant at Tomsk Polytechnic University’s Materials Science Division, pyrolysis also helped remove polymers, produce a solid carbon residue and collect gaseous products. The average carbon residue yield reached 45.8 per cent of the processed material’s mass. The researchers also found that preliminary pyrolysis eliminated iron silicide from the final product, reducing unwanted impurities and increasing the proportion of silicon carbide.
Further experiments examined how the amount of carbon affected the reaction. When its share in the initial mixture increased from zero to 30 per cent, the proportion of silicon carbide in the solid product rose from 46 to 61 per cent. At the same time, free silicon content fell from 19.7 to 8.3 per cent, while silicon dioxide decreased from 3 per cent to trace amounts.
The findings indicate that adding carbon helps more silicon participate in the chemical reaction, improving the composition of the resulting material. Silicon carbide can be used to manufacture abrasives, refractory products, heating elements and components for power electronics, offering a way to turn discarded solar panels into a resource for advanced materials production.