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Minggu, 20 November 2011

sodium silicate PT Ajidharmamas Tritunggal Sakti

PT AJIDHARMAMAS TRITUNGGAL SAKTI
www.union.co.id
From Wikipedia, the free encyclopedia
ATS waterglass in drum
Sodium silicate is the common name for a compound sodium metasilicate, Na2SiO3, also known as water glass or liquid glass. It is available in aqueous solution and in solid form and is used in cements, passive fire protection, refractories, textile and lumber processing, and automobiles. Sodium carbonate and silicon dioxide react when molten to form sodium silicate and carbon dioxide:
Na2CO3 + SiO2 → Na2SiO3 + CO2
Anhydrous sodium silicate contains a chain polymeric anion composed of corner shared {SiO4} tetrahedral, and not a discrete SiO3 ion. In addition to the anhydrous form, there are hydrates with the formula Na2SiO3·nH2O (where n = 5, 6, 8, 9) which contain the discrete, approximately tetrahedral anion SiO2(OH)2 with water of hydration. For example, the commercially available sodium silicate pentahydrate Na2SiO3·5H2O is formulated as Na2SiO2(OH)2·4H2O and the nonahydrate Na2SiO3·9H2O is formulated as Na2SiO2(OH)2·8H2O.
In industry, the different grades of sodium silicate are characterized by their SiO2:Na2O ratio, which can vary between 2:1 and 3.75:1. Grades with this ratio below 2.85:1 are termed ‘alkaline’. Those with a higher SiO2:Na2O ratio are described as ‘neutral’.

History

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Water Glass was defined in Von Wagner’s Manual of Chemical Technology (1892 translation) as any of the soluble alkaline silicates, first observed by Van Helmont in 1640 as a fluid substance made by melting sand with excess alkali. Glauber made what he termed “fluid silica” in 1648 from potash and silica. Von Fuchs, in 1825, obtained what is now known as water glass by treating silicic acid with an alkali, the result being soluble in water, “but not affected by atmospheric changes”. Von Wagner distinguished soda, potash, double(soda and potash), and fixin as types of water glass. The fixing type was “a mixture of silica well saturated with potash water glass and a sodium silicate” used to stabilize inorganic water color pigments on cement work for outdoor signs and murals.

Properties

Sodium silicate is a white powder that is readily soluble in water, producing an alkaline solution. It is one of a number of related compounds which include sodium orthosilicate, Na4SiO4, sodium pyrosilicate, Na6Si2O7, and others. All are glassy, colourless and dissolve in water.
Sodium silicate is stable in neutral and alkaline solutions. In acidic solutions, the silicate ion reacts with hydrogen ions to form silicic acid, which when heated and roasted forms silica gel, a hard, glassy substance.

CAS registry number and EINECS number

Each and every substance has its own unique CAS registry number and EINECS number. The CAS No. and EINECS No. of sodium silicate and other related substances are:
Substance Name CAS# EC#(EINECS No.)
Silicic acid, sodium salt 1344-09-8 239-981-7
disodium metasilicate 6834-92-0 229-912-9
Sodium silicate 15859-24-2 215-687-4

Uses

Metal repair

Sodium silicate is used, along with magnesium silicate, in muffler repair and fitting paste. When dissolved in water, both sodium silicate, and magnesium silicate form a thick paste that is easy to apply. When the exhaust system of an internal combustion engine heats up to its operating temperature, the heat drives out all of the excess water from the paste. The silicate compounds that are left over have glass-like properties, making a temporary, brittle repair.

Automotive repair

Sodium silicate can be used to seal leaks at the head gasket. A common use is when an aluminum alloy cylinder head engine is left sitting for extended periods or the coolant is not changed at proper intervals, electrolysis can “eat out” sections of the head causing the gasket to fail.
Rather than remove the cylinder head, “liquid glass” is poured into the radiator and allowed to circulate. The waterglass is injected via the radiator water into the hotspot at the engine. This technique works because at 100-105 °C the sodium silicate loses water molecules to form a very powerful sealant that will not re-melt below 810 °C.
A sodium silicate repair of a leaking head gasket can hold for up to two years and even longer in some cases. The effect will be almost instant, and steam from the radiator water will stop coming out the exhaust within minutes of application. This repair only works with water-to-cylinder or water-to-air applications and where the sodium silicate reaches the “conversion” temperature of 100-105 °C.

Homebrewing

Sodium silicate flocculant properties are also used to clarify wine and beer by precipitating colloidal particles. But as a clearing agent sodium silicate (water glass) is sometimes confused with isinglass (a form of gelatin prepared from collagen extracted from the dried swim bladders of sturgeon and other fishes). Eggs preserved in a bucket of waterglass gel, and their shells, are sometimes also used (baked and crushed) to clear wine.

Car engine disablement

Sodium silicate solution is used to inexpensively, quickly, and permanently disable automobile engines. Running an engine with about 2 liters of a sodium silicate solution instead of motor oil causes the solution to precipitate, catastrophically damaging the engine’s bearings and pistons within a few minutes. In the United States, this procedure was required by the Car Allowance Rebate System (CARS) program.

Adhesive

One common example of its use as a paper cement was for producing paper cartridges for black powder revolvers produced by Colt’s Manufacturing Company during the period from 1851 until 1873, especially during the American Civil War. Sodium silicate was used to seal combustible nitrated paper together to form a conical paper cartridge to hold the black powder, as well as to cement the lead ball or conical bullet into the open end of the paper cartridge. Such sodium silicate cemented paper cartridges were inserted into the cylinders of revolvers, thereby speeding the reloading of cap and ball black powder revolvers. This use largely ended with the introduction of Colt revolvers employing brass-cased cartridges starting in 1873.
When used as a paper cement, the tendency is for the sodium silicate joint eventually to crack within a few years, at which point it no longer holds the paper surfaces cemented together.

Aquaculture

Sodium silicate gel is also used as a substrate for algal growth in aquaculture hatcheries.

Food preservation

Sodium silicate was also used as an egg preservation agent in the early 20th century with large success. When fresh eggs are immersed in it, bacteria which cause the eggs to spoil are kept out and water is kept in. Eggs can be kept fresh using this method for up to nine months. When boiling eggs preserved this way, it is well advised to pin-prick the egg to allow steam to escape because the shell is no longer porous.

Drilling fluids

Sodium silicate is frequently used in drilling fluids to stabilize borehole wells and to avoid the collapse of bore walls. It is particularly useful when drill holes pass through argillaceous formations containing swelling clay minerals such as smectite or montmorillonite.

Concrete and general masonry treatment

Concrete treated with a sodium silicate solution helps to significantly reduce porosity in most masonry products such as concrete, stucco, plasters. A chemical reaction occurs with the excess Ca(OH)2 (portlandite) present in the concrete that permanently binds the silicates with the surface making them far more wearable and water repellent. It is generally advised to apply this treatment only after the initial cure has taken place (7 days or so depending on conditions). These coatings are known as silicate mineral paint.www.union.co.id

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