sodium silicate PT Ajidharmamas Tritunggal Sakti
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| ATS waterglass in drum |
- Na2CO3 + SiO2 → Na2SiO3 + CO2
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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| cullet |
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.
