... 25Kg/Bag Silica Fume 1. InstructionMicrosilica , also called silica fume or micro silica, is a byproduct of producing silicon metal or ferrosilicon alloys. Silicon metal and alloys are ... , such as concrete, grouts, and mortars as well as elastomeric, polymer, refractory, ceramic and rubber applications.HS No.: 28112200 China Origin, microsilica meets the requirements ...