Method of Preparing High Purity and Small Particle Size Nano-Silica from Decommissioned Composite Insulators

With the further development of power grids, composite insulators are widely used due to its various excellent properties. However, with the growth of the usage time, more and more composite insulators have been retired or are facing retirement. A large number of retired composite insulators contain a large amount of silicone rubber materials that are difficult to degrade naturally, bringing serious pressure on the environment. In this paper, the constant value pyrolysis method is adopted for green recycling of retired insulators. Firstly, the various products and chemical reactions occurring in the pyrolysis process of silicone rubber are investigated in detail by thermogravimetric analysis test and gas chromatography-mass spectrometry (GC-MS). Secondly, the effect of constant temperature time on the expect products is investigated at a fixed pyrolysis temperature and heating rate. Last, we optimize the recovery device to obtain spherical nano-silica with a purity of more than 98% and a pore size of 113 nm, which greatly improve the recovery rate of silicone rubber and create great economic benefits.