... high purity, high SiO2 composition, high electrical resistance, lowest thermal expansion and exceptionally ... to create high purity, high SiO2 composition, high electrical resistance, lowest thermal expansion and exceptionally good thermal ... shell moulds, silicon rubbers, and electrical insulators. SPECIFICATIONS:Size : 1-100mmsSiO2 : 99.90MINFe2O3 : 15ppm maxLi2O : 1.0ppm maxAl2O3 : 25ppm-100ppmK2O : ...