Product Description

What Is Microsilica (= Silica-Fume)?
Microsilica (= Silica fume) is a byproduct of producing silicon metal or ferrosilicon alloys. Silicon metal and alloys are produced in electric furnaces. The raw materials are quartz, coal, and woodchips. The smoke that results from furnace operation is collected and sold as silica fume, rather than being landfilled. Perhaps the most important use of this material is as a mineral admixture in concrete. Silica fume consists primarily of amorphous (non-crystalline) silicon dioxide (SiO2). The individual particles are extremely small, approximately 1/100th the size of an average cement particle. Because of its fine particles, large surface area, and the high SiO2 content, silica fume is a very reactive pozzolan when used in concrete. The quality of silica fume is specified by ASTM C 1240 and AASHTO M 307. Microsilica (silica fume) is an amorphous silicon dioxide SiO2 which is generated as a gas in submerged electrical arc furnaces during the reduction of very pure quartz. As the molten metal is produced, a silica-based gas is emitted. This gaseous fume, as it rises, cools rapidly and forms extremely fine and minute, Amorphous, spherical particles. The microsilica is collected in a bag house, a system for filtering the hot air and gases vented from the furnace. This gas vapor is condensed in bag house collectors as very fine powder of spherical particles that average 0.1 to 0.3 microns in diameter with a surface area of 17 to 30 m2/g.

Silica Fume (Microsilica) Other Applications:
a) In Elastomers / Polymers: Used as a filler in rubber or plastic. b) Fertilizer: Used in defluorination process during the production of dicalcium phosphate (animal feed). c) Oil & Gas Wells: Used in down hole grouting operations, improves flow (lightweight) and decreases permeability. d) Fiber Cement: Used to improve strength and permeability of corrugated roofing panels. e) Shotcrete is sprayed concrete: Silica Fume reduces rebound & increases bonding strength, productivity and savings in material cost.

Silica Fume (Micro Silicon) Applications in Refractories:
As a new material, Microsilica (that is in powder form) is widely used in the refractory industry. It has an important effect on the improvement of the amorphous refractory. The practical application is in the following aspects: 1. Instead of pure aluminum oxide as refractories. 2. The production of amorphous and shaped refractory products as additives makes the strength and high temperature performance greatly improved. 3. The overall casting ladle coagulant. 4. Other cohesive agents, binders, coagulants and additives for other refractory products

Silica Fume (Microsilica) Applications in Concrete:
The micro silica (Silica fume) powder can be well filled in the cement particle space and make the slurry more dense, mainly in the following: 1. Increase strength: The compressive strength and flexural strength of concrete increase greatly, adding 5-10% micro silica fume, the compressive strength can be increased by 10-30%, and the flexural strength will be increased more than 10%. 2. Increase the density: The impermeability is increased by 5-18 times, and the anti-chemical ability is increased by more than 4 times. 3. Frost resistance: After 300-500 rapid freeze-thaw cycles, the relative elastic modulus of micro silica powder decreased by 10-20%, while ordinary concrete decreased to 30-73% through 25-50 cycles. 4. Early strength: micro silica concrete makes the induction period shortened and has the characteristics of early strength. 5. Anti-abrasion and anti-cavitation resistance: punching resistance of micro silicon fume concrete improve 0.5-2.5 times than ordinary concrete, and anti-cavitation ability is improved 3-16 times.