Micro silica, also known as silica fume, it is a very fine pozzolanic material, composed of amorphous silica produced  by electric arc furnaces as a byproduct of the  production  of elemental silicon or ferro silicon alloys.  Microsilica can be used in a variety of cementitious products such as anti-craking agent, drilling industry, glass industry concrete, grouts,and mortars as well as elastomer,  polymer, refractory, ceramic