How much does silica fume cost?

How much does silica fume cost?

Condensed silica fume costs from $400-$1,000/ton, which is significantly higher than portland cement ($90/ton).

Who makes fumed silica?

Major global producers are Evonik (who sells it under the name Aerosil), Cabot Corporation (Cab-O-Sil), Wacker Chemie (HDK), Dow Corning, Heraeus (Zandosil), Tokuyama Corporation (Reolosil), OCI (Konasil), Orisil (Orisil) and Xunyuchem(XYSIL).

Is silica fume cheaper than cement?

Silica fume is much cheaper than cement therefore it is very important from economical point of view. Silica fume also decrease the voids in concrete.

Is fumed silica the same as silica fume?

Fumed silica and silica fumed are two different terms for two substance. They are both silica dioxide. On some occasions people confused with them. They have different derivations, technical characteristics, and applications, then the price is different.

How do you make silica fume?

Silica fume is a by-product from the production of elemental silicon or alloys containing silicon in electric arc furnaces. At a temperature of approximately 2000°C the reduction of high-purity quartz to silicon produces silicon dioxide vapor, which oxidizes and condenses at low temperatures to produce silica fume.

What is silica fume used for in concrete?

Silica fume, a by-product of the ferrosilicon industry, is a highly pozzolanic material that is used to enhance mechanical and durability properties of concrete. It may be added directly to concrete as an individual ingredient or in a blend of portland cement and silica fume.

How do you make fumed silica?

Fumed silicas are created through flame hydrolysis synthesis. This involves burning carbon-containing coal in a furnace containing oxygen gas at high temperatures (1100°C). The gaseous products condense onto existing precipitated silica particles, which produces fumed silicas.

Is silica fume environmentally friendly?

The use of silica fume (SF) in different engineering applica- tions provides an important advantage in environmentally and economically sustainable ways. SF has been used both as a partial cement replacement in concrete production [17–21] and to improve the engineering properties of problematic soils [22–24].

What are the disadvantages of high silica cement?

Disadvantages of Silica Fume/Micro Silica In case the external temperature is high, it will lead to early dry shrinkage. Hence, it is more prone to cracks which may ultimately affect the overall strength. The construction with the silica fume concrete is difficult; as workability of silica fume concrete is poor.

Is silica fume toxic?

* High exposure to Silica, Amorphous (Fume) can cause a flu-like illness with headache, fever, chills, aches, chest tightness and cough. * Repeated exposure to Silica, Amorphous (Fume) can cause lung damage (fibrosis).

What is the percentage of silica fume in concrete?

Silica fume has been used as an addition to concrete up to 15% by weight of cement, although the normal proportion is 7 to 10%.

Is silica still used in concrete?

Concrete and masonry products contain silica sand. Since concrete and masonry are primary building materials, there are numerous ways for construction workers to be exposed.

How do you add silica fume to concrete?

Adding method (1) Put in aggregate, then put in silica fume, cement and dry mix, then add water and other additives. (2) Put in coarse aggregate + 75% water + silica fume + 50% fine aggregate, stir for 15-30 seconds, then put in cement + concrete admixture + 50% fine aggregate + 25% water, and stir until uniform.

How do you store fumed silica?

Due to this, it is recommended that fumed silica be stored in a clean, dry area away from chemical vapors at ambient temperatures. Further, it is recommended that fumed silica packaged in paper bags be used within two years after manufacture date as bags may begin deteriorating beyond this time period.

Is fumed silica harmful?

* Silica, Amorphous (Fume) can irritate the eyes on contact. Repeated exposure can damage the eyes. * High exposure to Silica, Amorphous (Fume) can cause a flu-like illness with headache, fever, chills, aches, chest tightness and cough. * Repeated exposure to Silica, Amorphous (Fume) can cause lung damage (fibrosis).

Is fumed silica flammable?

Suitable Extinguishing Media: Silica is non-combustible, therefore no extinguishing media needs to be identified.

What is silica fume used for?

What are the impacts of fly ash on the environment?

Due to its small size and light it has potential to get airborne and pollute the environment. The oxides of iron and aluminium present on the surface of the flyash particles attract toxic trace elements, such as Sb, As, Be, Cd, Pb, Hg, Se, V and they are found to be concentrated largely on the surface of flyash.