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Sodium silicate
Sodium silicate
Sodium silicate
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Na2SiO3

Sodium silicate is a generic name for chemical compounds with the formula Na
2xSi
yO
2y+x or (Na
2O)
x·(SiO
2)
y, such as sodium metasilicate (Na
2SiO
3), sodium orthosilicate (Na
4SiO
4), and sodium pyrosilicate (Na
6Si
2O
7). The anions are often polymeric. These compounds are generally colorless transparent solids or white powders, and soluble in water in various amounts.

Sodium silicate is also the technical and common name for a mixture of such compounds, chiefly the metasilicate, also called waterglass, water glass, or liquid glass. The product has a wide variety of uses, including the formulation of cements, coatings, 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 sodium silicate are characterized by their SiO2:Na2O weight ratio (which can be converted to molar ratio by multiplication with 1.032). The ratio can vary between 1:2 and 3.75:1.[1] Grades with ratio below 2.85:1 are termed alkaline. Those with a higher SiO2:Na2O ratio are described as neutral.

History

[edit]

Soluble silicates of alkali metals (sodium or potassium) were observed by European alchemists in the 16th century. Giambattista della Porta observed in 1567 that tartari salis (cream of tartar, potassium bitartrate) caused powdered crystallum (quartz) to melt at a lower temperature.[2] Other possible early references to alkali silicates were made by Basil Valentine in 1520,[3] and by Agricola in 1550. Around 1640, Jan Baptist van Helmont reported the formation of alkali silicates as a soluble substance made by melting sand with excess alkali, and observed that the silica could be precipitated quantitatively by adding acid to the solution.[4]

In 1646, Glauber made potassium silicate, which he called liquor silicum, by melting potassium carbonate (obtained by calcinating cream of tartar) and sand in a crucible, and keeping it molten until it ceased to bubble (due to the release of carbon dioxide). The mixture was allowed to cool and then was ground to a fine powder.[5] When the powder was exposed to moist air, it gradually formed a viscous liquid, which Glauber called "Oleum oder Liquor Silicum, Arenæ, vel Crystallorum" (i.e., oil or solution of silica, sand or quartz crystal).[6]

However, it was later claimed that the substances prepared by those alchemists were not waterglass as it is understood today.[7] That would have been prepared in 1818 by Johann Nepomuk von Fuchs, by treating silicic acid with an alkali; the result being soluble in water, "but not affected by atmospheric changes".[8]

The terms "water glass" and "soluble glass" were used by Leopold Wolff in 1846,[9] by Émile Kopp in 1857,[10] and by Hermann Krätzer in 1887.[11]

In 1892, Rudolf Von Wagner distinguished soda, potash, double (soda and potash), and fixing (i.e., stabilizing) 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.[12][13][14][15]

Properties

[edit]

Sodium silicates 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.[citation needed] When dried up it still can be rehydrated in water.[16]

Sodium silicates are stable in neutral and alkaline solutions. In acidic solutions, the silicate ions react with hydrogen ions to form silicic acids, which tend to decompose into hydrated silicon dioxide gel.[citation needed] Heated to drive off the water, the result is a hard translucent substance called silica gel, widely used as a desiccant. It can withstand temperatures up to 1100 °C.[citation needed]

Production

[edit]

Solutions of sodium silicates can be produced by treating a mixture of silica (usually as quartz sand), caustic soda, and water, with hot steam in a reactor. The overall reaction is

2x NaOH + SiO
2 → (Na
2O)
x·SiO
2 + x H
2O

Sodium silicates can also be obtained by dissolving silica SiO
2 (whose melting point is 1713 °C) in molten sodium carbonate (that melts with decomposition at 851 °C):[17]

x Na
2CO
3 + SiO
2 → (Na
2O)
x·SiO
2 + x CO
2

The material can be obtained also from sodium sulfate (melting point 884 °C) with carbon as a reducing agent:

2x Na
2SO
4 + C + 2 SiO
2 → 2 (Na
2O)
x·SiO
2 + 2 SO
2 + CO
2

In 1990, 4 million tons of alkali metal silicates were produced.[1]

Ferrosilicon

[edit]
Further information: Ferrosilicon § Hydrogen production

Sodium silicate may be produced as a part of hydrogen production by dissolving ferrosilicon in an aqueous sodium hydroxide (NaOH·H2O) solution:[18]

2NaOH + Si + H2O → Na2SiO3 + 2H2

Bayer process

[edit]

Though unprofitable, Na2SiO3 is a byproduct of Bayer process which is often converted to calcium silicate (Ca2SiO4).

Uses

[edit]

The main applications of sodium silicates are in detergents, paper industry (as a deinking agent), water treatment, and construction materials.[1]

Adhesives

[edit]

The adhesive properties of sodium silicate were noted as early as the 1850s[19] and have been widely used at least since the First World War.[20] The largest application of sodium silicate solutions is a cement for producing cardboard.[1] When used as a paper cement, the sodium silicate joint tends to crack within a few years, at which point it no longer holds the paper surfaces cemented together.

Sodium silicate solutions can also be used as a spin-on adhesive layer to bond glass to glass[21] or a silicon dioxide–covered silicon wafer to one another.[22] Sodium silicate glass-to-glass bonding has the advantage that it is a low-temperature bonding technique, as opposed to fusion bonding.[21] It also requires less processing than glass-to-glass anodic bonding,[23] which requires an intermediate layer such as silicon nitride (SiN) to act as a diffusion barrier for sodium ions.[23] The deposition of such a layer requires a low-pressure chemical vapor deposition step.[23] A disadvantage of sodium silicate bonding, however, is that it is very difficult to eliminate air bubbles.[22] This is in part because the technique does not require a vacuum and also does not use field assistance[clarification needed] as in anodic bonding.[24] 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 nanofluidic cavity or MEMS elements.

Coatings

[edit]

Sodium silicate may be used for various paints and coatings, such as those used on welding rods. Such coatings can be cured in two ways. One method is to heat a thin layer of sodium silicate into a gel and then into a hard film. To make the coating water-resistant, high temperatures of 100 °C (212 °F; 373 K) are needed.[16] The temperature is slowly raised to 150 °C (302 °F; 423 K) to dehydrate the film and avoid steaming and blistering. The process must be relatively slow, but infrared lamps may be used at first.[16] In the other method, when high temperatures are not practical, the water resistance may be achieved by chemicals (or esters), such as boric acid, phosphoric acid, sodium fluorosilicate, and aluminium phosphate.[16] Before application, an aqueous solution of sodium silicate is mixed with a curing agent.[16]

It is used in detergent auxiliaries such as complex sodium disilicate and modified sodium disilicate. The detergent granules gain their ruggedness from a coating of silicates.[1]

Water treatment

[edit]

Sodium silicate is used as an alum coagulant and an iron flocculant in wastewater treatment plants. Sodium silicate 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 sodium silicate. Their electrical double layer collapses due to the increase of ionic strength caused by the addition of sodium silicate (doubly negatively charged anion accompanied by two sodium cations) and they subsequently aggregate. This process is called coagulation.[1]

Foundries, refractories and pottery

[edit]
Main article: Sand casting § Sodium silicate
See also: Calcium silicate

It is used as a binder of the sand when doing sand casting of all common metals. It allows for the rapid production of a strong mold or core by three main methods.[citation needed]

  • Method 1 requires passing carbon dioxide gas through the mixture of sand and sodium silicate in the sand molding box or core box. The carbon dioxide reacts with the sodium silicate to form solid silica gel and sodium carbonate.[citation needed] This provides adequate strength to remove the now hardened sand shape from the forming tool. Additional strength occurs as any unreacted sodium silicate in the sand shape dehydrates.
  • Method 2 requires adding an ester (reaction product of an acid and an alcohol) to the mixture of sand and sodium silicate before it is placed into the molding box or core box. As the ester hydrolyzes from the water in the liquid sodium silicate, an acid is released which causes the liquid sodium silicate to gel. Once the gel has formed, it will dehydrate to a glassy phase as a result of syneresis. Commonly used esters include acetate esters of glycerol and ethylene glycol as well as carbonate esters of propylene and ethylene glycol. The higher the water solubility of the ester, the faster the hardening of the sand.[citation needed]
  • Method 3 requires microwave energy to heat and dehydrate the mixture of sand and sodium silicate in the sand molding box or core box. The forming tools must pass through microwaves for this to work well. Because sodium silicate has a high dielectric constant, it absorbs microwave energy very rapidly. Fully dehydrated sand shapes can be produced within a minute of microwave exposure. This method produces the highest strength of sand shapes bonded with sodium silicate.[citation needed]

Since the sodium silicate does not burn during casting (it can actually melt at pouring temperatures above 1800 °F), it is common to add organic materials to provide for enhanced sand breakdown after casting. The additives include sugar, starch, carbons, wood flour and phenolic resins.

Water glass is a useful binder for solids, such as vermiculite and perlite. When blended with the latter lightweight fraction, water glass can be used to make hard, high-temperature insulation boards used for refractories, passive fire protection, and high-temperature insulations, such as in moulded pipe insulation applications. When mixed with finely divided mineral powders, such as vermiculite dust (which is common scrap from the exfoliation process), one can produce high temperature adhesives. The intumescence[clarification needed] disappears in the presence of finely divided mineral dust, whereby the waterglass becomes a mere matrix. Waterglass is inexpensive and abundantly available, which makes its use popular in many refractory applications.

Sodium silicate is used as a deflocculant in casting slips helping reduce viscosity and the need for large amounts of water to liquidize the clay body. It 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. Sodium silicate is brushed on a section of the piece. After five minutes, the wall of the piece is stretched outward with a rib or hand. The result is a wrinkled or cracked look.

It is also the main agent in "magic water", which is used when joining clay pieces, especially if the moisture level of the two differs.[25]

Dyes

[edit]

Sodium silicate 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, it is allowed to dry, after which the sodium silicate is painted on to the dyed fabric, covered with plastic to retain moisture, and left to react for an hour at room temperature.[26]

Repair work

[edit]

Sodium silicate is used, along with magnesium silicate, in muffler repair and fitting paste. Magnesium silicate can be mixed with a solution of sodium silicate to 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 that can be reinforced with glass fibre.[citation needed]

Sodium silicate can be used to fill gaps in the head gasket of an engine. This is especially useful for aluminium alloy cylinder heads, which are sensitive to thermally induced surface deflection. Sodium silicate is added to the cooling system through the radiator and allowed to circulate. When the sodium silicate reaches its "conversion" temperature of 100–105 °C (212–221 °F), it loses water molecules and forms a glass seal with a re-melting temperature above 810 °C (1,490 °F). This repair can last two years or longer, and symptoms disappear instantly. However, this repair works only when the sodium silicate reaches its "conversion" temperature. Also, sodium silicate (glass particulate) contamination of lubricants is detrimental to their function, and contamination of engine oil is a serious possibility in situations in which a coolant-to-oil leak is present.

Sodium silicate solution is used to inexpensively, quickly, and permanently disable automobile engines. Running an engine with half a U.S. gallon (or about two 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.[27] In the United States, this procedure was used to comply with requirements of the Car Allowance Rebate System (CARS) program.[27][28]

Construction

[edit]

A mixture of sodium silicate and sawdust has been used in between the double skin of certain safes. This not only makes them more fire resistant, but also makes cutting them open with an oxyacetylene torch extremely difficult due to the smoke emitted.

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

Concrete treated with a sodium silicate solution helps to reduce porosity in most masonry products such as concrete, stucco, and plasters. This effect aids in reducing water penetration, but has no known effect on reducing water vapor transmission and emission.[29] 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 durable and water repellent. This treatment generally is applied only after the initial cure has taken place (approximately seven days depending on conditions). These coatings are known as silicate mineral paint. An example of the reaction of sodium silicate with the calcium hydroxide found in concrete to form calcium silicate hydrate (CSH) gel, the main product in hydrated Portland cement, follows.[30]

Na
2SiO
3 + y H
2O + x Ca(OH)
2 → x CaO.SiO
2.y H
2O + 2NaOH

Crystal gardens

[edit]

When crystals of a number of metallic salts are dropped into a solution of water glass, simple or branching stalagmites of colored metal silicates are formed. This phenomenon has been used by manufacturers of toys and chemistry sets to provide instructive enjoyment to many generations of children from the early 20th century until the present. An early mention of crystals of metallic salts forming a "chemical garden" in sodium silicate is found in the 1946 Modern Mechanix magazine.[31] Metal salts used included the sulfates and/or chlorides of copper, cobalt, iron, nickel, and manganese.

Sealants

[edit]

Sodium silicate with additives was injected into the ground to harden it and thereby to prevent further leakage of highly radioactive water from the Fukushima Daiichi nuclear power plant in Japan in April, 2011.[32] The residual heat carried by the water used for cooling the damaged reactors accelerated the setting of the injected mixture.

On June 3, 1958, the USS Nautilus, the world's first nuclear submarine, visited Everett and Seattle. In Seattle, crewmen dressed in civilian clothing were sent in to secretly buy 140 quarts (160 liters) of an automotive product containing sodium silicate (originally identified as Stop Leak) to repair a leaking condenser system. The Nautilus was en route to the North Pole on a top secret mission to cross the North Pole submerged.[33]

Firearms

[edit]

A historical use of the adhesive properties of sodium silicates is the production of paper cartridges for black powder revolvers produced by Colt's Manufacturing Company between 1851 and 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.[34][35] Similarly, sodium silicate was also used to cement the top wad into brass shotgun shells, thereby eliminating any need for a crimp at the top of the brass shotgun shell to hold a shotgun shell together. Reloading brass shotgun shells was widely practiced by self-reliant American farmers during the 1870s, using the same waterglass material that was also used to preserve eggs. The cementing of the top wad on a shotgun shell consisted of applying from three to five drops of waterglass on the top wad to secure it to the brass hull. Brass hulls for shotgun shells were superseded by paper hulls starting around 1877. The newer paper-hulled shotgun shells used a roll crimp in place of a waterglass-cemented joint to hold the top wad in the shell. However, whereas brass shotshells with top wads cemented with waterglass could be reloaded nearly indefinitely (given powder, wad, and shot, of course), the paper hulls that replaced the brass hulls could be reloaded only a few times.

Food and medicine

[edit]
World War I poster suggesting the use of waterglass to preserve eggs

Sodium silicate and other silicates are the primary components in "instant" wrinkle remover creams, which temporarily tighten the skin to minimize the appearance of wrinkles and under-eye bags. These creams, when applied as a thin film and allowed to dry for a few minutes, can present dramatic results. This effect is not permanent, lasting from a few minutes up to a couple of hours. It works like water cement, once the muscle starts to move, it cracks and leaves white residues on the skin.

Waterglass has been used as an egg preservative with large success, primarily when refrigeration is not available. Fresh-laid eggs are immersed in a solution of sodium silicate (waterglass). After being immersed in the solution, they are removed and allowed to dry. A permanent air tight coating remains on the eggs. If they are then stored in appropriate environment, the majority of bacteria which would otherwise cause them to spoil are kept out and their moisture is kept in. According to the cited source, treated eggs can be kept fresh using this method for up to five months. When boiling eggs preserved that way, the shell is no longer permeable to air, and the egg will tend to crack unless a hole in the shell is made (e.g., with a pin) in order to allow steam to escape.[36]

Sodium silicate's flocculant properties are also used to clarify wine and beer by precipitating colloidal particles. As a clearing agent, though, sodium silicate is sometimes confused with isinglass which is prepared from collagen extracted from the dried swim bladders of sturgeon and other fishes. Eggs can be preserved in a bucket of waterglass gel, and their shells are sometimes also used (baked and crushed) to clear wine.[37]

Sodium silicate gel is also used as a substrate for algal growth in aquaculture hatcheries.[38]

See also

[edit]

References

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Sodium silicate

View on Grokipedia
from Grokipedia
Sodium silicate, also known as water glass or liquid glass, is a versatile composed of (Na₂O) and (SiO₂), with a general of Na₂O · x SiO₂ where x is the molar ratio of SiO₂ to Na₂O (typically 1.5–3.3 for commercial grades, e.g., around 3.22 for some). It typically appears as a colorless, viscous or a white to grayish-white solid, exhibiting strong alkaline properties with a of 11–13 in solution due to its ionic nature. This compound is highly soluble in , forming stable colloidal solutions, and is valued for its , binding, and buffering capabilities across numerous industries. Industrial production of sodium silicate primarily involves the high-temperature fusion of silica sand (SiO₂) with soda ash (Na₂CO₃) in a furnace at approximately 1,100–1,300°C, yielding a solid that is then dissolved in hot water under pressure to produce the liquid form. Alternative hydrothermal methods react caustic soda (NaOH) with silica sources like or waste cullet in an at elevated temperatures and pressures, offering a more energy-efficient route for certain ratios. The resulting product can be adjusted for specific SiO₂/Na₂O ratios, influencing its viscosity, density (typically 1.3–1.5 g/cm³), and reactivity. Sodium silicate serves as a key ingredient in detergents and cleaning agents, where it acts as a builder to soften , prevent soil redeposition, and stabilize enzymes. In and refractories, it functions as a binder for cements, mortars, and fireproof coatings, enhancing durability and heat resistance in applications like molds and acid-resistant linings. Additional uses include for inhibition, aids, and iron sequestration; paper production as a surface agent; and adhesives for , , and textiles. Its role in , rod coatings, and even organic agriculture as a and floatant underscores its broad utility.

Overview

Definition and forms

Sodium silicate is an composed of (Na₂O) and silica (SiO₂), primarily represented by the Na₂SiO₃, though it exists commercially as a range of mixtures with the general composition Na₂O · nSiO₂, where n typically varies from 1 to 3.75. This variability in the silica-to-soda ratio allows for tailored properties in industrial applications, with the compound acting as a salt where serves as the to sodium. The term "water glass" originates from the material's characteristic glassy appearance, forming a vitreous solid upon drying or solidification of its solutions. Sodium silicate is available in several common forms to suit different uses: liquid solutions, often viscous syrups with 20-50% solids content dissolved in ; powdered solids, such as or hydrated metasilicates; and granular solids, typically produced by crushing fused lumps. Commercial grades of sodium silicate are primarily distinguished by their SiO₂/Na₂O weight ratio, which influences , , and reactivity; ratios below 2.85:1 are classified as alkaline, while those above are neutral. For example, neutral grades like Type N have ratios around 3.2:1, with typical densities of 1.3-1.5 g/cm³ and viscosities ranging from 100-500 centipoise (cps), making them suitable for applications requiring slower dissolution. Quick-dissolving variants feature modified ratios or formulations for faster solubilization in water. These grades are standardized by manufacturers to ensure consistency in properties like specific gravity and solids content.

Nomenclature

Sodium silicate is the generic term for a series of compounds composed of (Na₂O) and (SiO₂) in varying proportions, often represented by the general formula (Na₂O)_x · (SiO₂)_y. Common names for these compounds include water glass, liquid glass, and soluble glass, reflecting their glassy appearance in solid form and solubility in water. The systematic IUPAC distinguishes specific forms based on structure; for example, the metasilicate Na₂SiO₃ is named disodium metasilicate or disodium dioxido(oxo), while the Na₄SiO₄ is termed tetrasodium or tetrasodium . Other variants, such as polysilicates with higher silica content, are designated as sodium polysilicates. Compositions are frequently denoted by the molar of SiO₂ to Na₂O (often symbolized as "n" or "module"), such as a 2.0 expressed as Na₂O · 2SiO₂. This influences descriptive ; for instance, products with ratios below approximately 2.85 are classified as alkaline sodium silicates, whereas those with higher ratios are known as neutral grades, and high-silica variants may be referred to as soda.

History

Discovery and early uses

The formation of alkali silicates as a soluble substance was first reported around 1640 by Flemish chemist , who obtained it by melting silica (sand) with excess caustic potash, serving as an early analog to sodium silicate through the reaction of silica with an alkali. The first deliberate preparation of sodium silicate occurred in 1818, when German mineralogist Johann Nepomuk von Fuchs fused soda ash () with silica to produce a water-soluble form of the compound. In the late , sodium silicate saw initial applications as a for eggs, where immersion in its solution formed a thin protective on the shells to inhibit bacterial penetration and extend freshness. During the , Fuchs conducted demonstrations highlighting the material's notable in —contrasting with ordinary —and its glass-like transparency and when dried, sparking interest in its potential beyond settings.

Industrial development

The industrial production of sodium silicate, often referred to as water glass, began to take shape in the mid-19th century following early scientific advancements in . In the 1850s, the first commercial manufacturing plants were established in and the , marking the transition from laboratory experiments to large-scale operations. These plants capitalized on processes developed by Johann Nepomuk von Fuchs in the 1820s, who had pioneered the production of soluble silicates in , enabling the synthesis of sodium silicate from silica and soda ash under heat. By the late , production expanded significantly to support emerging applications in materials, , and adhesives. Key innovations included patents for using sodium silicate as a binder in artificial stone and compositions; for instance, British inventor Frederick Ransome secured patents in the 1860s for processes combining sodium silicate with and calcium chloride to produce durable cast stone blocks, which gained popularity as cost-effective alternatives to natural stone in building projects. This period saw the establishment of major producers, such as the Quartz Company (later PQ Corporation), founded in 1831 by Elkinton and beginning commercial sodium silicate production in 1861 to supply soap manufacturers, evolving into a leading global supplier by the early 1900s. The 20th century witnessed explosive growth in sodium silicate output, driven by post-World War II industrial expansion in consumer goods and infrastructure. Demand surged for its roles in detergents as a builder to enhance cleaning efficiency and in for inhibition and , aligning with the rise of synthetic detergents and municipal water systems in the 1950s and 1960s. By 2000, global production had reached approximately 3-4 million metric tons annually. Production continued to grow in the , reaching about 8.4 million metric tons as of 2025, reflecting its status as a high-volume chemical essential to modern industry.

Structure and properties

Molecular structure

Sodium silicate is an ionic compound composed of sodium cations (Na⁺) and polymeric anions derived from -oxygen tetrahedra. The anions vary depending on the specific form: for example, orthosilicates feature discrete [SiO₄]⁴⁻ units, while metasilicates exhibit chain-like [SiO₃]²⁻ structures where atoms are linked via bridging oxygen atoms. In solid state, sodium silicate predominantly exists as an amorphous due to its network-forming nature, but certain hydrates adopt crystalline forms, such as the nonahydrate Na₂SiO₃·9H₂O (phase V). The , denoted by n in the general (Na₂O)·n(SiO₂), determines the anionic architecture: low n values (e.g., n=0.5 for ) result in isolated SiO₄ , whereas higher n (e.g., n=1 for metasilicate) leads to infinite linear chains or layered sheets connected by Si-O-Si bridges, enhancing the structural connectivity. Raman and () spectroscopy confirm the presence of these Si-O-Si linkages in sodium silicate structures. Raman spectra display characteristic bands near 1050–1200 cm⁻¹ attributed to symmetric stretching of bridging Si-O-Si bonds in the polymeric network, while ²⁹Si reveals distinct chemical shifts for Qⁿ species (where n=0–4 indicates the number of bridging oxygens per ), supporting the tetrahedral coordination and extent.

Physical properties

Sodium silicate exists in various forms, including solids, hydrated crystals, and aqueous solutions, each exhibiting distinct physical characteristics. In its form, sodium silicate appears as a white to grayish-white or flakes, often with a glassy texture due to its amorphous nature. Aqueous solutions are typically colorless and transparent, though they can become cloudy or viscous at higher concentrations. The of is 2.61 g/cm³. For common commercial aqueous solutions containing around 40% sodium silicate, the ranges from 1.3 to 1.5 g/cm³ at , varying with the SiO₂ to Na₂O ratio and exact concentration. These densities influence handling and application in industrial processes. The of pure Na₂SiO₃ is around 1089°C, though this value can vary slightly with the degree of hydration and specific composition; hydrated forms decompose or soften at lower temperatures rather than melting sharply. Sodium silicate is highly soluble in , with exceeding 20 g/100 mL at 25°C for the metasilicate form, allowing for concentrated solutions up to 40% by weight at . These solutions form strongly alkaline mixtures with values typically between 11 and 13. It is insoluble in alcohols and most organic solvents. The of aqueous sodium silicate solutions varies significantly with concentration, SiO₂:Na₂O , and , ranging from about 10 cP for dilute solutions to over 1000 cP for concentrated ones at 20°C. For instance, a 40% solution with a ratio of 3.22 may exhibit viscosities of 25 to 2500 mPa·s, making it suitable for applications requiring flow control. This property arises partly from polymeric silicate anions in solution, as noted in structural analyses.

Chemical properties

Sodium silicate displays pronounced when dissolved in water, arising from its to generate ions and ions, thereby elevating the of the solution. This behavior stems from the partial dissociation of the anion, represented approximately by the equation \ceNa2SiO3+H2O⇌2NaOH+H2SiO3,\ce{Na2SiO3 + H2O ⇌ 2NaOH + H2SiO3}, where (\ceH2SiO3\ce{H2SiO3}) forms alongside , though the reaction is more accurately described as an equilibrium involving polymeric species and \ceOH−\ce{OH-}. The extent of hydrolysis depends on the SiO₂:Na₂O ratio, with lower ratios yielding more alkaline solutions due to greater availability of \ceNa+\ce{Na+} ions. In reactions with acids, sodium silicate neutralizes the acid while precipitating , which often gels upon standing. A representative example is its interaction with : \ceNa2SiO3+2HCl−>2NaCl+H2SiO3,\ce{Na2SiO3 + 2HCl -> 2NaCl + H2SiO3}, producing a white as \ceH2SiO3\ce{H2SiO3} polymerizes and dehydrates to form hydrated silica. This reaction proceeds vigorously with strong acids, generating heat and potentially violent effervescence, but is less intense with weaker acids like acetic acid. Sodium silicate shows resistance to dilute acids under neutral or alkaline conditions but is susceptible to (HF), which dissolves the silicate framework by forming soluble (\ceSiF4\ce{SiF4}). Thermally, sodium silicate remains stable at ambient temperatures but decomposes at elevated heat, typically above 600°C, to yield and : \ceNa2SiO3−>Na2O+SiO2.\ce{Na2SiO3 -> Na2O + SiO2}. This decomposition is endothermic and contributes to its use in high-temperature applications, though hydrated forms lose prior to oxide formation. Additionally, sodium silicate exhibits complexing ability, binding polyvalent metal ions in solution through or precipitation of metal silicates, which can facilitate formation under controlled and temperature. For instance, it captures ions like Ca²⁺ or Mg²⁺ by releasing Na⁺, forming stable complexes. In terms of oxidation states, sodium maintains +1 and silicon +4 in \ceNa2SiO3\ce{Na2SiO3}, rendering the compound inert to processes under standard conditions.

Production

Furnace process

The furnace process represents the primary industrial method for manufacturing sodium silicate through the thermal fusion of silica sand (SiO₂) and (Na₂CO₃) in a high-temperature furnace, typically operating between 1000°C and 1400°C. This approach yields a solid glassy material known as cullet, which is later dissolved to produce liquid sodium silicate solutions with varying SiO₂/Na₂O ratios. The process is favored for its straightforward use of abundant raw materials and ability to produce consistent, high-quality output suitable for bulk production. The core reaction for a 1:1 molar ratio is Na₂CO₃ + SiO₂ → Na₂SiO₃ + CO₂, though the SiO₂ proportion is increased to achieve higher SiO₂/Na₂O (up to 3.2:1) in the final product by adjusting the raw material blend. Raw materials are precisely mixed in Na₂CO₃:SiO₂ ranging from 1:2 to 1:3.5 to tailor the silicate composition. The blend is then charged into rotary or furnaces, where it melts into a . Upon completion of the fusion, the melt is rapidly quenched—often by pouring onto water-cooled rollers or into —to solidify into cullet fragments. These solids are fed into steam-heated autoclaves for dissolution under (typically 8-10 bar and 140-180°C), yielding a clear liquid sodium silicate solution that is filtered for final use. Key advantages of the furnace process include its capacity for high-purity output due to minimal impurities in the starting materials and excellent scalability for solid silicate production in large facilities. Conversion efficiencies reach 90-95%, minimizing waste, while the method's energy requirements are approximately 5.9 GJ per metric ton in standard industrial setups. This technique has been a staple in large-scale plants since the mid-19th century, enabling widespread commercialization.

Precipitation process

The precipitation process for sodium silicate production encompasses secondary wet-chemical methods at lower temperatures, often utilizing industrial byproducts or alternative silica sources. A prominent variant involves hydrothermal treatment of silica-rich byproducts, such as (a byproduct of metal production) or rice husk ash (an agricultural waste), with caustic soda (NaOH) solution at temperatures of 150–200°C and pressures around 0.7–1.5 MPa. The silica in these materials reacts with NaOH to form soluble sodium silicate, which is subsequently filtered from undissolved residues and concentrated. This process achieves silica extraction efficiencies of 70–90% depending on ash pretreatment and conditions, producing a liquid sodium silicate suitable for direct use. These methods offer key advantages, including effective utilization of waste streams to minimize disposal and , as well as lower energy requirements compared to furnace processes. They are particularly suited for high-purity liquid sodium silicates with SiO₂/Na₂O ratios adjustable from 2:1 to 3.5:1, ideal for specialized applications. However, production remains on a smaller scale (typically <10,000 tons/year per facility) and is heavily dependent on byproduct supply from sectors like agriculture or metallurgy, limiting widespread adoption. These approaches gained traction post-1950s amid growing emphasis on sustainable chemical , with hydrothermal variants from agricultural wastes emerging prominently in the late 20th and early 21st centuries.

Applications

Construction and repair

Sodium silicate serves as an accelerator in concrete mixtures, typically added at 1-2% by weight of cement to expedite the setting process through the formation of and (C-S-H) that enhances early hydration. This addition promotes rapid strength development, making it suitable for applications requiring quick curing, such as and repair works. In soil stabilization, sodium silicate is injected into sandy soils to form a durable silicate cement, a technique pioneered in the Joosten process since the 1920s for reinforcing foundations and preventing subsidence. The solution reacts with to create an insoluble gel that binds soil particles, improving load-bearing capacity in loose formations. For repair applications, sodium silicate seals cracks in concrete by reacting with atmospheric CO₂ and available calcium ions to form , effectively filling voids and restoring integrity, particularly in historic building restoration where minimal intervention is preferred. Sodium silicate is also mixed with other silicates, such as potassium or lithium variants, to produce intumescent coatings applied to steel structures for fireproofing, where it expands under heat to form a protective insulating barrier. Early innovations include German patents from the 1880s, such as the 1886 Jeziorsky patent, which described silicate-based mortars for filling voids and creating air-setting refractory compositions in construction.

Adhesives and sealants

Sodium silicate serves as a versatile binder in adhesive formulations due to its ability to form an irreversible gel upon exposure to acids or carbon dioxide (CO₂), which creates a strong, durable bond particularly effective on porous surfaces like paper and wood. This gelation mechanism involves the polymerization of silicate ions, resulting in a silica network that adheres firmly by penetrating and hardening within substrate pores. The process is triggered by acidification, which neutralizes the alkaline solution and promotes silica precipitation, or by CO₂ absorption, leading to the formation of sodium carbonate and a solid silicate matrix. In adhesive applications, sodium silicate solutions, typically at concentrations of 20-50% solids, are widely used for bonding cardboard boxes, laminating paper, and assembling wood products, often blended with fillers such as starch to enhance viscosity and cost-effectiveness. These adhesives provide rapid setting times and strong initial tack, making them ideal for high-speed manufacturing of corrugated board and cartons, where they account for a significant portion of low-cost bonding needs. For wood bonding, the silicate's penetration into fibers ensures robust shear strength, though it is most prevalent in non-structural applications like furniture assembly. As a sealant, sodium silicate is employed in pipe joint compounds and boiler repairs, where it reacts to form a hard, impermeable silicate matrix that withstands thermal stress and prevents leaks. In these formulations, the gel hardens upon contact with moisture or CO₂ in the environment, creating a flexible yet durable barrier suitable for high-temperature plumbing and exhaust systems. To improve water resistance, sodium silicate is commonly blended with polymers such as polyvinyl acetate (PVA) or fine powders like zinc oxide, which cross-link the silicate structure and reduce moisture sensitivity in demanding environments. Historically, sodium silicate emerged as one of the first commercial adhesives in the mid-19th century, with production ramping up in the 1850s for applications like paper bonding, including early uses in bookbinding and cartridge production. By the 1890s, it gained prominence in corrugated box manufacturing, revolutionizing packaging adhesives and contributing to an estimated global consumption of around 1-2 million tons annually in adhesive sectors today, with packaging representing a major share.

Water treatment and detergents

Sodium silicate serves as a coagulant aid in water treatment processes, particularly in flocculation, where it is added at dosages typically ranging from 0.5 to 4 mg/L (0.5–4 ppm) to enhance the formation of durable silica-based flocs that capture suspended particles and organic matter, thereby improving turbidity removal in municipal and industrial plants. This application, utilizing activated silica derived from sodium silicate, has been employed since the 1930s to strengthen flocs and facilitate better settling and filtration efficiency. In the process, the silicate ions contribute to floc aggregation, aiding the removal of colloidal impurities and reducing overall treatment costs in coagulation systems paired with primary coagulants like alum or iron salts. In detergent formulations, sodium silicate functions as a corrosion inhibitor, often incorporated at 5–10% by weight alongside phosphates to protect metal surfaces in washing equipment from alkaline degradation. It precipitates divalent cations such as Ca²⁺ and Mg²⁺ as finely divided calcium silicate, preventing the formation of adherent scales and deposits that impair cleaning performance, with particular importance in automatic dishwashers where hard water can lead to filming on glassware and buildup in machine components. This precipitation mechanism enhances detergent efficacy by maintaining water softness and supporting the dispersion of soils during the wash cycle. As a pH buffer in boiler water treatment, sodium silicate helps maintain alkalinity in the range of pH 10–11, which inhibits acid corrosion of metal surfaces by promoting protective oxide layers and ensuring silica remains soluble to avoid scaling. This buffering action stabilizes the boiler environment, reducing the risk of localized pitting and extending equipment life in high-pressure steam systems. Following environmental regulations in the 1970s that restricted phosphates due to eutrophication concerns, sodium silicate emerged as a key phosphate replacement in detergents, providing similar builder functions without contributing to waterway pollution. Globally, its use in water treatment and detergents accounts for approximately 3 million tons annually as of 2024. A representative reaction in scale prevention involves the silicate anion reacting with calcium ions: \ceSiO32−+Ca2+−>CaSiO3v\ce{SiO3^2- + Ca^2+ -> CaSiO3 v}, forming an insoluble precipitate that removes hardness-causing ions from solution.

Foundry and ceramics

Sodium silicate serves as a key binder in the production of cores, where it is typically incorporated at 3-5% by weight into sand mixtures to form molds and cores. The binder hardens through CO₂ gassing, which reacts with the silicate to create a strong, inorganic silicate bond that withstands the thermal stresses of . This process enables the creation of complex internal shapes in castings, such as those required for engine blocks or intricate machinery components, offering precision and structural integrity without the need for organic resins. In refractories, sodium silicate is utilized in the formulation of firebricks and pottery glazes due to its ability to provide resistance and enhance bonding. When mixed with alumina, it contributes to high-temperature stability, allowing refractories to endure environments up to 1400°C while maintaining mechanical strength and resistance to . These properties make it suitable for applications in industrial furnaces and where durability under corrosive and high-heat conditions is essential. In production, sodium silicate functions as a deflocculant in clay slips, reducing and improving flow during by neutralizing particle charges for more uniform dispersion. This facilitates the of thin-walled or detailed forms, enhancing efficiency in mold filling and reducing defects like cracking or uneven thickness. The use of sodium silicate in and ceramics offers advantages such as low cost and the absence of volatile organic compounds (VOCs), making it an environmentally preferable alternative to traditional organic binders. No-bake systems, introduced in the , employ esters as catalysts to enable self-setting molds, providing rapid curing and improved collapsibility for easier sand reclamation post-. Global consumption in foundries remains significant, supporting widespread adoption in operations.

Food, medicine, and miscellaneous uses

Sodium silicate is approved by the U.S. (FDA) as a (GRAS) substance for use as an anticaking or free-flow agent, drying agent, , and processing aid in various foods, particularly in powdered products where it prevents clumping by absorbing . Historically, solutions of sodium silicate, known as water glass, were used to preserve eggs for several months by sealing their porous shells against bacterial entry and loss, a method popular before widespread but now largely obsolete due to modern storage techniques. It also finds use in certain dental cements, where it contributes to pulp protection by forming a barrier that supports tissue and prevents further irritation in vital pulp therapies. In production, sodium silicate acts as a surface agent to improve strength, printability, and resistance to and oils, enhancing the quality of writing and papers. For , it is used in rod coatings to bind fluxes and provide arc stability during . In organic agriculture, sodium silicate serves as an approved and floatant to control pests and diseases on crops, such as in and production, by creating a physical barrier on surfaces. Among miscellaneous uses, sodium silicate solutions are employed in educational demonstrations to create "crystal gardens," where metal salts like chloride are added to the solution, resulting in colorful silicate crystal formations that illustrate and reactions for students. In firearm maintenance, it serves as a component in some bore cleaners to dissolve lead and residues from gun barrels, aiding in residue removal without damaging metal surfaces. For textiles, sodium silicate acts as a fixative and pH buffer in processes with reactive dyes, enhancing color stability and penetration into fibers during hand- applications. In hobby and educational contexts, sodium silicate is used to demonstrate by mixing it with alcohols or acids to form bouncy gels or putty-like materials, providing hands-on insight into silicate chemistry. On a small scale, it provides passive fireproofing for wood or fabric by coating surfaces to form an layer that resists ignition and flame spread, suitable for DIY projects like treating shop tables or items. Regulatory limits restrict its direct use to levels not exceeding , with GRAS status applying specifically to approved concentrations below 2% in formulations like syrups or washes.

Safety and environmental impact

Health and safety considerations

Sodium silicate, particularly in solution form, acts as a mild to severe depending on concentration and exposure duration, primarily due to its high with a typically ranging from 11 to 13. Direct contact with can cause burns or irritation, manifesting as redness, pain, and potential blistering, while eye exposure may lead to severe damage including corneal burns and vision impairment. Inhalation of dust or aerosolized mist from sodium silicate can irritate the , causing coughing, , and of the upper airways. Acute oral is low, with an LD50 greater than 2,000 mg/kg in rats, indicating it is not highly poisonous if ingested in small amounts but can still cause gastrointestinal burns. Safe handling of sodium silicate requires the use of (PPE), including chemical-resistant gloves, safety goggles or face shields, and protective clothing to prevent skin and . Respiratory protection, such as a or , is recommended when handling dry forms or in poorly ventilated areas to avoid hazards. Storage should occur in cool, dry locations in tightly sealed containers to minimize exposure to in the air, which can trigger gelation and reduce product stability; temperatures below freezing should be avoided to prevent separation. Spills should be neutralized with a mild like dilute acetic acid before cleanup to reduce . Occupational exposure limits for sodium silicate dust follow general standards, with no specific OSHA PEL; it is often regulated under nuisance dust limits of 15 mg/m³ (total dust) and 5 mg/m³ (respirable fraction) as an 8-hour , or the amorphous silica PEL of (80 mg/m³)/(%SiO₂) for total dust. Chronic exposure primarily poses risks rather than systemic effects, and unlike crystalline silica, amorphous forms in sodium silicate do not contribute to due to their non-fibrogenic structure. Monitoring and , such as local exhaust ventilation, are essential in workplaces involving dry powders or spraying. In case of exposure, measures emphasize immediate : for contact, remove contaminated clothing and flush the affected area with copious amounts of for at least 15 minutes, followed by neutralization with dilute if residual persists; seek medical attention for severe burns. Eye exposure requires flushing with or saline for 15-20 minutes while holding eyelids open, with immediate professional evaluation. For , move the individual to fresh air and provide oxygen if breathing is difficult; respiratory support may be needed. calls for rinsing the and seeking urgent medical care without inducing vomiting to avoid further esophageal damage. Under REACH regulations, sodium silicate is classified as causing severe skin burns (Skin Corr. 1, H314), serious eye damage (Eye Dam. 1, H318), and may cause respiratory irritation (STOT SE 3, H335), but it is not listed as a or as of 2025. Classifications vary by concentration and SiO₂:Na₂O molar ratio (typically 1.5–4.0), as noted in 2025 USDA assessments. These classifications guide labeling and risk management in the , emphasizing preventive measures over exposure. In the United States, it falls under OSHA's Hazard Communication Standard without specific carcinogenicity designation.

Environmental effects

Sodium silicate, also known as water glass, exhibits favorable biodegradability in aquatic environments due to the natural occurrence of ions in water bodies. Upon dilution and exposure to environmental conditions, it hydrolyzes into harmless silica and sodium ions, with silica integrating into natural biogeochemical cycles without long-term accumulation. Studies indicate low to aquatic organisms such as and , with LC50 values typically exceeding 300 mg/L. Despite its biodegradability, sodium silicate effluents present potential risks related to and water quality alterations. The high of sodium silicate solutions (typically 11-12) can elevate stream pH levels upon discharge, potentially disrupting microbial communities and aquatic ecosystems if not neutralized. Additionally, the sodium component may contribute to increased in receiving waters, exacerbating stress on salinity-sensitive organisms in coastal or arid regions. While silicates are essential s for diatoms, elevated local concentrations from industrial emissions could alter nutrient ratios like N:Si and P:Si, influencing composition and potentially promoting non-diatom blooms. Effective waste management practices enhance the environmental of sodium silicate. Residual sodium silicate can be recycled into by converting waste glass cullet into sodium silicate solutions via hydrothermal or fusion processes, reducing the need for virgin raw materials and diverting waste from . In landfill disposal, solidified sodium silicate behaves as an inert material with minimal leaching potential, though dust control measures are essential to prevent airborne particulate exposure during handling. The production and use of sodium silicate demonstrate a relatively low compared to alternatives like , with emissions estimated at approximately 1.07 tons of CO₂ equivalent per ton produced via conventional furnace methods. Sustainability efforts have advanced since 2010 through the adoption of biomass-derived silica sources, such as rice husk ash, which provide renewable feedstocks for sodium silicate synthesis and reduce reliance on energy-intensive . These biobased routes further lower by up to 50% in some processes while promoting principles. Regulatory frameworks address sodium silicate's environmental impacts, particularly in management. The U.S. Environmental Protection Agency (EPA) mandates adjustment for industrial effluents containing sodium silicate to maintain discharge limits between 6.0 and 9.0, preventing alkalinity-related harm to aquatic systems. In detergents, sodium silicate serves as a biodegradable builder alternative to phosphates, aligning with EPA Safer Choice standards and reducing risks from runoff.

References

  1. https://pubchem.ncbi.nlm.nih.gov/compound/Sodium-Silicate
  2. https://www.ams.usda.gov/sites/default/files/media/Sodium%2520Silicate%2520TR%25202011.pdf
  3. https://www.chemicalbook.com/article/sodium-silicate-introduction-production-uses-and-health-hazards.htm
  4. https://www.chemicalbook.com/article/sodium-silicate-production-and-uses.htm
  5. https://www.sciencedirect.com/science/article/abs/pii/S0008884618307518
  6. https://www.epa.gov/system/files/documents/2023-03/Sodium%2520Silicate%2520Supply%2520Chain%2520Profile.pdf
  7. https://www.specialchem.com/adhesives/guide/sodium-silicate-adhesives
  8. https://www.ams.usda.gov/sites/default/files/media/2025-LS_TR-SodiumSilicate-Crops-FINAL_508.pdf
  9. https://byjus.com/chemistry/sodium-silicate/
  10. https://www.britannica.com/science/water-glass
  11. https://www.dcmsme.gov.in/publications/pmryprof/glass/ch23.pdf
  12. https://www.univarsolutions.com/product-categories/silicones/silanes/sodium-silicates
  13. https://toomaminerals.com/en/product/sodium-silicate-powder/
  14. https://www.univarsolutions.com/sodium-silicate-solution-n-620307
  15. https://www.oxy.com/siteassets/documents/chemicals/products/other-essentials/ss-sales-lss-50.pdf
  16. https://www.sigmaaldrich.com/US/en/product/sigald/338443
  17. https://www.chemicalbook.com/ChemicalProductProperty_EN_CB6284996.htm
  18. https://webbook.nist.gov/cgi/inchi?ID=C6834920&Mask=2
  19. https://www.epa.govt.nz/database-search/chemical-classification-and-information-database-ccid/view/B36653EB-B5BC-4A61-9306-91728EF9B2A0
  20. https://patents.google.com/patent/US3821119A/en
  21. https://www.atamanchemical.com/sodium-silicate-mod-3_u25003/
  22. https://petrichor-farm.com/blog/f/the-old-ways-water-glassing-eggs
  23. https://www.cees-silicates.org/index.php/silicates
  24. https://www.ingessil.com/en/storiasodiosilicato
  25. https://www.pqcorp.com/history/
  26. https://hpvchemicals.oecd.org/ui/handler.axd?id=3cb4f34b-2afa-4004-b447-521188909235
  27. https://www.mordorintelligence.com/industry-reports/sodium-silicate-market
  28. https://pubchem.ncbi.nlm.nih.gov/compound/Sodium-silicate
  29. https://files.nocnt.ru/routine/senterra/2013/01-23/liter/mcmillan-structural-1984-am69_622.pdf
  30. https://chemicalsafety.ilo.org/dyn/icsc/showcard.display?p_card_id=0359
  31. https://www.fishersci.com/shop/products/sodium-silicate-solution-40-42-be-technical-fisher-chemical-2/SS3381
  32. https://www.chemicalbook.com/ChemicalProductProperty_US_CB2199386.aspx
  33. https://silmaco.com/sites/default/files/public/generated/files/products/MSDS-MET0-EN.pdf
  34. https://pubchem.ncbi.nlm.nih.gov/compound/sodium-metasilicate-_anhydrous
  35. https://link.springer.com/article/10.1007/s10953-007-9214-6
  36. https://www.univarsolutions.com/sodium-silicate-40-deg-be-clear-3929012
  37. https://www.chemicalaid.com/tools/equationbalancer.php?equation=Na2SiO3%2B%252B%2BH2O%2B%253D%2BNaOH%2B%252B%2BH2SiO3&hl=en
  38. https://www.sciencedirect.com/science/article/pii/S2238785420315180
  39. https://www.sciencedirect.com/science/article/abs/pii/0040603185854678
  40. https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cmtd.202100077
  41. https://www.ingessil.com/en/funzionisodiosilicato
  42. https://www.ingessil.com/en/processoproduttivosodio
  43. https://www.pqcorp.com/products/
  44. https://www.scribd.com/document/489206675/Sodium-Silicate-Project-Profile-edit
  45. https://www.sciencedirect.com/science/article/abs/pii/S0894177700000558
  46. https://www.nanotrun.com/article/sodium-silicate-an-overview-of-history-applications-and-modern-developments-i01749i1.html
  47. https://www.sciencedirect.com/science/article/pii/S0008884624000425
  48. https://www.researchgate.net/publication/378310886_Hydrothermal_synthesis_of_sodium_silicate_from_rice_husk_ash_Effect_of_synthesis_on_silicate_structure_and_transport_properties_of_alkali-activated_concrete
  49. https://www.drillingmanual.com/cement-slurry-accelerators-mechanism-chemistry/
  50. https://pubs.rsc.org/en/content/articlehtml/2019/ra/c8ra09901d
  51. https://www.researchgate.net/publication/340646579_Effect_of_Sodium_Silicate_on_Hardening_Property_on_Concrete
  52. https://pubs.acs.org/doi/10.1021/acs.chemrev.5b00014
  53. https://onlinepubs.trb.org/Onlinepubs/hrr/1972/381/381-007.pdf
  54. https://iopscience.iop.org/article/10.1088/0964-1726/25/8/084005
  55. https://www.uri.edu/news/2010/05/uri-research-on-self-healing-concrete-yields-cost-effective-system-to-extend-life-of-structures/
  56. https://pmc.ncbi.nlm.nih.gov/articles/PMC9145861/
  57. https://libraryarchives.metro.net/dpgtl/usdot/1977-chemical-grouts-in-soils-volume-1-avaliable-materials.pdf
  58. https://www.sciencedirect.com/science/article/abs/pii/S0001868623002038
  59. https://www.ask-chemicals.com/fileadmin/user_upload/Download_page/professional_articles/EN/FMT_Article_part13.pdf
  60. https://www.sciencedirect.com/topics/engineering/sodium-silicate
  61. https://chemicalstore.com/sodium-silicate-liquid/
  62. https://fosterproducts.com/wp-content/uploads/2017/01/Childers_INSP_SelectionGuide_R0517.pdf
  63. https://ieeexplore.ieee.org/document/6466192
  64. https://pubs.acs.org/doi/pdf/10.1021/bk-1982-0194.ch001
  65. https://www.industryresearch.biz/market-reports/sodium-silicate-market-111181
  66. https://www.suezwaterhandbook.com/water-and-generalities/fundamental-physical-chemical-engineering-processes-applicable-to-water-treatment/coagulation-floculation/typical-reagents
  67. https://www.sciencedirect.com/topics/engineering/coagulant-aid
  68. https://www.sciencedirect.com/science/article/abs/pii/S0304389410015475
  69. https://water.mecc.edu/courses/ENV110/lesson4_print.pdf
  70. https://www.nrc.gov/docs/ML0633/ML063390143.pdf
  71. https://www.products.pcc.eu/wp-content/uploads/2022/06/Formulation-quide_ADW_.pdf
  72. https://abshishe-zarrin.ir/en/sodium-silicate-in-detergent-industry-en/
  73. https://www.dow.com/en-us/pdp.acusol-588g-polyphosphate-and-silicate-scale-inhibitor.182632z.html
  74. https://www.globalwaterintel.com/articles/performance-under-pressure-high-quality-boiler-feedwater-from-hard-water-magna-imperio-systems
  75. https://www.steamforum.com/pictures/water%2520treat%2520Boilers%281%29.pdf
  76. https://cen.acs.org/articles/88/i4/Phosphate-Phaseout-Opportunity-Chemical-Suppliers.html
  77. https://www.quora.com/How-does-sodium-silicate-react-with-calcium-hydroxide
  78. https://www.hillandgriffith.com/post/sodium-silicate-binders
  79. https://link.springer.com/article/10.1007/s40962-022-00897-4
  80. https://www.sciencedirect.com/science/article/pii/0001868682850318
  81. https://www.chemicalbook.com/article/the-brief-introduction-of-sodium-silicate.htm
  82. https://www.sciencedirect.com/science/article/pii/S218707641400027X
  83. https://iransilicate.com/en/the-method-of-producing-refractory-materials-with-powdered-sodium-silicate/
  84. https://trinityceramic.com/product/sodium-silicate-trinity-ceramic/
  85. https://www.ask-chemicals.com/fileadmin/user_upload/Download_page/foundry_products_brochures/US/No_Bake_USA.pdf
  86. http://www.castingarea.com/education/history.htm
  87. https://hfpappexternal.fda.gov/scripts/fdcc/index.cfm?set=FoodSubstances&id=SODIUMSILICATE
  88. https://lakecountrymuseum.com/the-waterglass-method-of-egg-preservation/
  89. https://www.nature.com/articles/s41415-022-5157-y
  90. https://uwaterloo.ca/chem13-news-magazine/may-2019/feature/chemical-garden
  91. https://forums.sassnet.com/index.php?/topic/163916-how-do-you-tell-if-a-barrel-is-leaded/
  92. https://silmaco.com/en/application/textile
  93. https://www.pwsrcac.org/wp-content/uploads/Bouncing-Polymers.pdf
  94. https://rogergeorge.com/products/sodium-silicate
  95. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-184/subpart-B
  96. https://www.sigmaaldrich.com/sds/mm/1.05621
  97. https://www.oxy.com/siteassets/documents/chemicals/stewardship/liquid-sodium-silicates.pdf
  98. https://www.osha.gov/chemicaldata/613
  99. https://westliberty.edu/health-and-safety/files/2010/02/Sodium-silicate-solution.pdf
  100. https://pubs.acs.org/doi/10.1021/es0264697
  101. https://www.researchgate.net/publication/287186196_Conversion_of_waste_glasses_into_sodium_silicate_solutions
  102. https://www.geopolymer.org/wp-content/uploads/False-CO2-values.pdf
  103. https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cssc.202300762
  104. https://www.grandviewresearch.com/industry-analysis/us-liquid-sodium-silicate-lss-market
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