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CAS NUMBER: 13870-28-5
EC NUMBER: 237-623-4
MOLECULAR FORMULA: Na2O5Si2
MOLECULAR WEIGHT: 182.15
Disodium Disilicate is a crystalline powder at room temperature with a molecular weight of 198.148 g/mol.
The substance water solubility was determined to be very high, > 700 g/L.
Disodium Disilicate is degraded hydrolytically to monodisilicate ions (water glass) that are identical to naturally occurring Disilicate which is widespread in nature.
As the substance is solid and its boiling point is above 300°C the vapour pressure ofDisodium Disilicate (delta-crystalline)is expected to be very low, therefore little exposure via inhalation is expected.
In addition the logPow is expected to be very low as the substance is an inorganic compound that does not dissolve in n-octanol, therefore it can be assumed that very little direct absorption across the respiratory tract epithelium will occur.
Similarly, based on physical – chemical properties of Disodium Disilicate the substance is not likely to penetrate skin as the logPow – value and high water solubility do not favour dermal penetration.
Furthermore, application ofDisodium Disilicate to skin of rabbits did not cause irritation or corrosion nor systemic effects (mortality) in a skin irritation/corrosion study.
Applied to the skin of guinea pigs, no sensitising effects were observed.
Disodium Disilicate is a generic name for chemical compounds such as Disodium metaDisilicate Na2SiO3, Disodium orthoDisilicate Na4SiO4, and Disodium pyroDisilicate Na6Si2O7.
The anions are often polymeric.
These compounds are generally colorless transparent solids or white powders, and soluble in water in various amounts.
Disodium Disilicate is also the technical and common name for a mixture of such compounds, chiefly the metaDisilicate, also called waterglass, water glass, or liquid glass.
The product has a wide variety of uses, including the formulation of cements, passive fire protection, textile and lumber processing, manufacture of refractory ceramics, as adhesives, and in the production of silica gel.
The commercial product, available in water solution or in solid form, is often greenish or blue owing to the presence of iron-containing impurities.
In industry, the various grades of Disodium Disilicate are characterized by their SiO2:Na2O weight ratio (which can be converted to molar ratio by multiplication with 1.032).
Disodium Disilicate is hydrated and completely soluble in water.
Disodium Disilicate is produced in a state-of-the art granulation plant allowing a careful control of the composition (ratio, hydration, particle size) which ensures a stable product quality.
Disodium Disilicate, auxiliary in the processes of detergency as total substitute of the phosphates, through which the contamination of the waters is mitigated.
In powder and granulate presentation, thanks to its crystalline structure, it is the best and newest alternative used in the manufacture of powder detergents and in tablets as a softener of washing water by absorbing non-metallic ions Ca+2 and Mg+2.
Disodium Disilicate, also known as liquid glass, is a aqueous solution constituted by SiO2 (silicon dioxide) and Na2O (Disodium oxide), and by the variation of the weighted relation between both constituting oxides and the concentration of solids in the solution, it is possible to obtain different grades of Disodium Disilicates, with specific characteristics for each use in the different market segments.
Since Disodium Disilicate is easy to handle, non toxic and non-inflammable, Disodium Disilicate is a chemical product with a wide range of application, besides being an important option for replacement in formulas and processes aiming to become more environmentally friendly.
Disodium Disilicate is primarily called, is a flaked, inorganic, powdered and solid substance or Disodium salt.
Disodium Disilicate consists of Disilicate in the form of a counter ion.
The other name for this solution is Waterglass.
This solid powdered substance is water-soluble, and when dissolved in water, Disodium Disilicate produces alkaline solutions.
The solution consists of the polymeric anion.
Disodium Disilicate tends to be completely stable in neutral and alkaline solutions.
However, the case is entirely different when it is about using Disodium Disilicate in varied acidic solutions.
In that case, the hydrogen ions react with the Disilicate ions, thus giving rise to the silicic acids.
These acids further get broken into hydrated silicon.
When heated further, the solution gets rid of water and results in the production of silica gel which is a hard and translucent substance.
This substance is used on an extensive scale in the form of a desiccant.
Disodium Disilicate has the potential of withstanding temperatures up to 1100°C.
USES OF DISODIUM DISILICATE:
Disodium Disilicate board application is widely popular across the market.
The largest use of this solution is in the production of cardboard.
Disodium Disilicate is used at wastewater treatment units in the form of an iron flocculant and even as alum coagulant.
Disodium Disilicate finds usage in the form of a fixative in the hand dyeing procedure.
Disodium Disilicate is used for the preservation of food and even in aquaculture and home-brewing.
Disodium Disilicate is also in use in the field of pottery.
Disodium Disilicate is widely used in mineral flotation as depressant, dispersant and as controlling agent of some soluble ions.
For example, Disodium Disilicate interacts with calcium ions in solution forming nearly insoluble calcium Disilicate.
For industrial and sulfatetype minerals (barite), Disodium Disilicate is usually part of the reagent scheme.
Disodium Disilicate is extensively used in base-metal flotation.
-Adhesive:
The largest application of Disodium Disilicate solutions is a cement for producing cardboard.
When used as a paper cement, the tendency is for the Disodium Disilicate joint eventually to crack within a few years, at which point it no longer holds the paper surfaces cemented together.
Disodium Disilicate solutions can also be used as a spin-on adhesive layer to bond glass to glass or silicon oxide covered silicon wafers to one another.
Disodium Disilicate glass-to-glass bonding has the advantage that Disodium Disilicate is a low temperature bonding technique, as opposed to fusion bonding.
Disodium Disilicate is also less processing intensive than glass-to-glass anodic bonding, which requires an intermediate layer such as SiN to act as a diffusion barrier for Disodium ions.
Deposition of such a layer requires a low pressure chemical vapor deposition step.
A disadvantage of Disodium Disilicate bonding, however, is that it is very difficult to eliminate air bubbles.
This is due in part because this bonding technique doesn't require bonding in vacuum and Disodium Disilicate also doesn't use field assistance like in anodic bonding.
Though this lack of field assistance can sometimes be beneficial, because field assistance can provide such high attraction between wafers as to bend a thinner wafer and collapse[24] onto the nanofluidic cavity or MEMS elements.
-Drilling fluids:
Disodium Disilicate is frequently used in drilling fluids to stabilize borehole walls and to avoid the collapse of bore walls.
Disodium Disilicate is particularly useful when drill holes pass through argillaceous formations containing swelling clay minerals such as smectite or montmorillonite.
-Detergent auxiliaries:
Disodium Disilicate is used in detergent auxiliaries such as complex Disodium Disilicate and modified Disodium Disilicate.
The detergent granules gain their ruggedness from a coating of Disilicates.
-Water treatment:
Disodium Disilicate is used as an alum coagulant and an iron flocculant in wastewater treatment plants.
Disodium Disilicate binds to colloidal molecules, creating larger aggregates that sink to the bottom of the water column.
The microscopic negatively charged particles suspended in water interact with Disodium Disilicate.
Their electrical double layer collapses due to the increase of ionic strength caused by the addition of Disodium Disilicate (doubly negatively charged anion accompanied by two Disodium cations) and they subsequently aggregate.
-Sand casting:
Disodium Disilicate is used as a binder of the sand when doing sand casting of iron or steel.
Disodium Disilicate allows the rapid production of a strong mold, by passing CO2 through the mixture of sand and Disodium Disilicate in the mold box, which hardens it almost instantly.
-Dye auxiliary:
Disodium Disilicate solution is used as a fixative for hand dyeing with reactive dyes that require a high pH to react with the textile fiber.
After the dye is applied to a cellulose-based fabric, such as cotton or rayon, or onto silk, Disodium Disilicate is allowed to dry, after which the Disodium Disilicate is painted on to the dyed fabric, covered with plastic to retain moisture, and left to react for an hour at room temperature.
-Metal repair:
Disodium Disilicate is used, along with magnesium Disilicate, in muffler repair and fitting paste.
When dissolved in water, both Disodium Disilicate and magnesium Disilicate 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 Disilicate compounds that are left over have glass-like properties, making a temporary, brittle repair.
-Automotive repair:
Disodium Disilicate is also used currently as an exhaust system joint and crack sealer for repairing mufflers, resonators, tailpipes, and other exhaust components, with and without fiberglass reinforcing tapes.
In this application, the Disodium Disilicate (60–70%) is typically mixed with kaolin (40-30%), an aluminium Disilicate mineral, to make the Disodium Disilicate "glued" joint opaque.
The Disodium Disilicate, however, is the high-temperature adhesive; the kaolin serves simply as a compatible high-temperature coloring agent.
Some of these repair compounds also contain glass fibres to enhance their gap-filling abilities and reduce brittleness.
Disodium Disilicate can be used to fill gaps within the head gasket.
Commonly used on aluminum alloy cylinder heads, which are sensitive to thermally induced surface deflection.
This can be caused by many things including head-bolt stretching, deficient coolant delivery, high cylinder head pressure, overheating, etc.
Disodium Disilicate is added to the system through the radiator, and allowed to circulate.
Disodium Disilicate is suspended in the coolant until it reaches the cylinder head.
At 100–105 °C (212-221 °F), Disodium Disilicate loses water molecules to form a glass seal with a remelt temperature above 810 °C (1,490 °F).
A Disodium Disilicate repair can last two years or longer.
The repair occurs rapidly, and symptoms disappear instantly.
This repair works only when the Disodium Disilicate reaches its "conversion" temperature at 100–105 °C.
Contamination of engine oil is a serious possibility in situations in which a coolant-to-oil leak is present.
Disodium Disilicate (glass particulate) contamination of lubricants is detrimental to their function.
Disodium Disilicate solution is used to inexpensively, quickly, and permanently disable automobile engines.
Running an engine with about 2 liters of a Disodium Disilicate solution instead of motor oil causes the solution to precipitate, catastrophically damaging the engine's bearings and pistons within a few minutes.
-Pottery:
Disodium Disilicate is used as a deflocculant in casting slips helping reduce viscosity and the need for large amounts of water to liquidize the clay body.
Disodium Disilicate is also used to create a crackle effect in pottery, usually wheel-thrown.
A vase or bottle is thrown on the wheel, fairly narrow and with thick walls.
Disodium Disilicate is brushed on a section of the piece.
After 5 minutes, the wall of the piece is stretched outward with a rib or hand.
The result is a wrinkled or cracked look.
Disodium Disilicate is also the main agent in "magic water", which is used when joining clay pieces, especially if the moisture level of the two differs.
USAGE AREAS OF DISODIUM DISILICATE:
-Water treatment
-Paints and pigments
-Textile
-Chemical Industry
-Cements and refractory
-Soil consolidation
-Minering
-Detergents
-Foundry
-Ceramics
APPLICATIONS OF DISODIUM DISILICATE:
-Laundry detergents
-Detergents for institutional purposes
-Bar soap production
-Stickers for paper tubes and barrels, corrugated paper and angles
-Stickers for thermal and acoustic isolation
-Refractory materials and mortar
-Clay deflocculant in the ceramics industry
-Deflocculant in ore purification processes
-Agglomerant for briquetting and pelotization processes
-Agglomerant for granulation process
-Agglomerant for electrodes and welds production
-Hydrogen peroxide stabilizer for paper bleaching
-Detergent action in deinking process for recycled paper
-Agglomerant in the molding and core making for the foundry industry
-Production of pigments
-Soil consolidation
-Production of additives for cements and sealing
-Surface treatment for concrete floors
-Main raw material for precipitated silica, coloidal silica, Disodium aluminoDisilicate and synthetic zeolites
-Production of lithographic slabs
-Auxiliary in oil wells drilling
ADVANTAGES OF DISODIUM DISILICATE:
-White and free-flowing granules and powders
-High bulk density
-Excellent buffering capacity
-Good bleach stabilizing properties
-Effective corrosion inhibition
-Outstanding binding properties to metals, ceramics, glasses and fibers
-High temperature resistance (up to 1600°C)
-Non-toxic and non-flammable
PROPERTIES OF DISODIUM DISILICATE:
Disodium Disilicates are colorless glassy or crystalline solids, or white powders.
Except for the most silicon-rich ones, they are readily soluble in water, producing alkaline solutions.
Disodium Disilicates are stable in neutral and alkaline solutions.
In acidic solutions, the Disilicate ions react with hydrogen ions to form silicic acids, which tend to decompose into hydrated silicon dioxide gel.
Disodium Disilicate can withstand temperatures up to 1100 °C.
Disodium Disilicate is crystalline and colourless glassy solid.
Disodium Disilicate can even be defined as a white powder.
Disodium Disilicates that are high in their content of silicon can easily dissolve in water.
CHEMICAL PROPERTIES OF DISODIUM DISILICATE:
Disodium Disilicate,NA2Si03 also known as a liquid glass, Disilicate of soda, Disodium metaDisilicate, and soluble glass, is a grayish-white crystalline powder that has a melting point of 1088 °C (1990 °F).
Disodium Disilicate is soluble in water and has strong detergent and emulsifying properties.
Disodium Disilicate is used to fireproof textiles, insulate electric wire, protect wood and porous stone, grease proof paper containers, and as a catalyst in refining high-octane gasoline.
SYNONYM:
13870-28-5
Disodium Disilicate n-hydrate
UNII-W64N8HUI60
W64N8HUI60
Disodium;oxido-[oxido(oxo)silyl]oxy-oxosilane
DTXSID50891889
EINECS 237-623-4
Silicic acid (H2Si2O5), Disodium salt
EC 237-623-4
UNII-IJF18F77L3 component OQEVSCYDUYRAAM-UHFFFAOYSA-N
