What is Microsilica?

Microsilica, also known as silica fume, is an ultrafine powder with high SiO2 content and high pozzolanic activity. It is used as a property-enhancing material in many areas, such as concrete construction, refractory, chemical fertilizer.

Silicon, ferrosilicon and other silicon alloys are produced by reducing quartz, with coal and iron or other ores at very high temperatures (2000°C) in electric arc furnaces. Some silicon gas (or ‘fume’) is produced in the process and reaches the top of the furnace with other combustion gases, where it becomes oxidized to silica by the air and then condenses as submicroscopic particles and agglomerated particles (0.1–0.5 μm) of amorphous silica. This material is usually known as condensed silica fume (csf) or ‘micro silica’, and consists of an ultrafine silica (85–96 per cent) powder between 50 and 100 times finer than cement or pfa.

Microsilica for use in concrete derives from the manufacture of ferrosilicon alloys and is processed into micropellets or slurries to facilitate handling. World supplies of micro silica are limited with total production probably being between 1 and 1.5 million tonnes, 80 percent of which is produced in the USA, USSR, Norway and Japan.387 The UK currently imports modest quantities of microsilica for use in concrete. In Iceland, blended microsilica-cement is used routinely as a precaution against ASR.388.



Anyang Lishi has been manufacturing and supplying microsilica since 1999. Our densified (compacted), semi-densified, and undensified microsilica products are with minimum SiO2 contents ranging from 85% to 97%, which have been used in many famous projects around the world. Anyang Lishi Industrial can also provide microsilica with higher SiO2 contents and specifications according to the requirements of customers.

Anyang Lishi Industrial microsilica complies with ASTM C 1240 and EN13263:2005 standards and has been recognized by SGS, ISO9001, and other famous test authorities. The recycling, densifying and filling processes are automatically integrated into a closed environment without any mixture or impurities. We can fix clients’ orders in a stable production base so as to ensure the consistency and stability of quality.


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