what is silica?

Answer 1

A white or colorless crystalline compound, SiO2, occurring abundantly as quartz, sand, flint, agate, and many other minerals and used to manufacture a wide variety of materials, especially glass and concrete.

Answer 2

The following website will tell you everything you need to know about "silica".

http://www.silicosis-net.org/news/silicosis-silica-news027.htm

Answer 3

The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. Siliceous is an adjective meaning "referring to silica"

Contents [hide]
1 In Nature
2 Applications
3 Health Effects
4 Chemistry
5 Reference
6 See also
7 External links



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In Nature
Silica is found in nature in several forms, including quartz and opal. In fact, it has 17 crystalline forms (see Nomenclature of Silica).

The most common constituent of sand in inland continental settings and non-tropical coastal settings is silica, usually in the form of quartz because the considerable hardness of this mineral resists erosion. However, the composition of sand varies according to local rock sources and conditions.

Variants found in high-pressure impacts are coesite and stishovite.

Many forms of life contain silica structures (Biogenic Silica), including microorganisms such as diatoms, plants such as horsetail, and animals such as hexactinellid sponges. It is present in the cell walls of various plants (including edible ones) to strengthen their structural integrity.

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Applications
Silica is manufactured in several forms including:

glass (a colorless, high-purity form is called fused silica)
synthetic amorphous silica
silica gel (used e.g. as desiccants in new clothes and leather goods)
It is used in the production of various products.

Inexpensive soda-lime glass is the most common and typically found in drinking glasses, bottles, and windows.
Silica, with alumina (silica-alumina), is a crucial ingredient in clay and allows for the development of an interlocking crystal matrix after firing in earthenware, stoneware and porcelain ceramic processes.
Silica is a major ingredient of Portland cement.
The ceramic re-entry heat protection tiles mounted on the bottom side of the Space Shuttles are made mostly of silica (see HRSI), as are the firebricks used in steel processing.
It is the substance upon which silica aerogels are based.
Silica is also used as a food additive, primarily as a flow agent in powdered foods, or to absorb water (see the ingredients list for Burger King).
The natural skin, or oxide coating, that grows on silicon is hugely beneficial in microelectronics. It is a marvellous insulator possessing high chemical stability, and in electrical applications it can protect the silicon, store charge, block current, and even act as a controlled pathway to allow small currents to flow through a device. At room temperature, however, it grows extremely slowly, and so to manufacture such oxide layers on silicon, the traditional method has been the deliberate heating of silicon in high temperature furnaces within an oxygen ambient.
Silica is the central component in most glass optical fibers.
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Health Effects
Inhaling crystalline silica dust can lead to silicosis or cancer.

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Chemistry
Silicon dioxide can be formed when silicon is exposed to oxygen (or air) at extremely high temperatures. This can occasionally happen naturally in fires, or when lightning strikes onto sand to create fulgurites.

Silicon dioxide is attacked by hydrofluoric acid (HF). HF is used to remove or pattern silicon dioxide in the semiconductor industry.

Answer 4

Main Entry: sil·i·ca
Pronunciation: 'si-li-k&
Function: noun
Etymology: New Latin, from Latin silic-, silex hard stone, flint
: silicon dioxide SiO2 occurring in crystalline, amorphous, and impure forms (as in quartz, opal, and sand respectively)

Answer 5

A type of sand

Answer 6

Sand, ordinary sand.