Colloidal Silica vs. Fumed Silica

Hebei Silicon Research Electronic Materials Co., L contains other products and information you need, so please check it out.

Applied Material Solutions offers a variety of industrial chemical products. In addition to colloidal silica, we provide a selection of antifoams and defoamers, hydrophobic treated silica, and toll manufacturing services. You&#;ll find our headquarters in Elkhorn, WI, while Burlington, WI, and Rockton, IL, are home to our manufacturing plants.

Here you&#;ll learn the differences between fumed silica and colloidal silica, which are otherwise identical at the molecular level. While AMS is a manufacturer of colloidal silica, we are not outright a manufacturer of fumed silica. Instead, we take fumed silica and surface-treat it with silicone polymers to make it hydrophobic.

What Is Colloidal Silica?

Colloidal silica is a water-based, stabilized dispersion of amorphous silicon dioxide (aka silica) nanoparticles. Manufacturers produce colloidal silicathrough the polymerization of silica nuclei derived from silicate solutions. Polymerized under alkaline conditions, the silica nuclei convert into silica sols (solid particles) at the nano-scale and with a high surface area. The process then applies a charge to these silica sols, causing electrostatic resistance between each particle and creating a colloid&#;a type of stable dispersion.

These microscopic colloids remain suspended in a dispersion medium, typically water. What makes colloids different from other suspensions is their even distribution, without settling or separating. Colloids can be comprised of many types of solid, gaseous, and liquid substances within a dispersion media. In the case of colloidal silica, the colloid is a microscopic solid dispersed in water.

What Is Fumed Silica?

 

Fumed silica is an amorphous, nano-scale, powdered material. Fumed silica particles are formed by injecting air and hydrogen flames with silicon tetrachloride or other types of chlorosilanes. Like colloidal silica, fumed silica particles are extremely small and have large surface areas. Furthermore, fumed silica particles have the same molecular composition as colloidal silica particles, except that they are presented in powdered form as opposed to a stabilized liquid dispersion.

What Are the Applications of Fumed Silica and Colloidal Silica?

Fumed silica functions as a desiccant that thickens various substances. For example, food manufacturers may use it to thicken liquid food products or prevent caking in powdered products. Other potential applications for fumed silica include cosmetics, toothpaste, and fillers in silicone elastomers. It also adjusts viscosity, alters rheology and modifies the physical characteristics of paints, coatings, adhesives and sealants.

If you want to learn more, please visit our website hydrophilic fumed silica.

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Similar to fumed silica, applications for colloidal silica include absorbing moisture in industrial settings with high moisture levels. Colloidal silica is also used to increase surface friction, facilitate the movement of materials, and as a binding agent.

Attributes of Fumed Silica and Colloidal Silica

Typical AttributesColloidal SilicaFumed Silica Physical StateLiquidPowder ConcentrationVariable - Often 6% - 50%Typically 100% CreationNucleation ReactionFlame Hydrolysis Common ApplicationsBinder, Densifier, CoagulantThickener, Stabilizer, Rheology Control Particle SizeVariable - Often 3 nm - 50 nmVariable - e.g. 5 nm - 20 nm Surface AreaVariable - Often 60 - 1,000 m2 /gVariable - e.g. 100 - 200 m2 /g Hydrophilic vs HydrophobicBoth. AMS manufactures hydrophilic colloidal silica.Both. AMS manufactures hydrophobic fumed silica.

Silicates From Applied Material Solutions

When selecting a colloidal silica or hydrophobic fumed silica, turn to Applied Material Solutions. We offer a wide variety of colloidal silica options, including winterized versions, and a versatile fumed silica in the form of our AMSil-F H22.

For more information about our silica products and other solutions, contact Applied Material Solutions today or call our offices at 262-723-.

Author: Subject: The Fumed Silica Mystery The Fumed Silica Mystery


Hello everyone,

I have been working with some fumed silica for a while now, its a incredibly fine and lightweight powder of glass that it produced by burning silicon tetrachloride with oxygen.

It works very well to gel fuel like mixes of gasoline and kerosene as a fuel source.

I have been trying to create a reusable gelling agent to do this, so one the fuel is burned, I can add more and the silica gels it, since the silica isn&#;t damaged by heat.

The problem is that after it is burned, the silica forms a very fragile chalky solid that does not gel anymore. It can absorb a little fuel, but it has poor performance as it forms little grains, and once they have absorbed the max amount of fuel it becomes a watery mix of the unabsorbed fuel, and fuel absorbed in the grains of silica

I have tried to solve this problem by adding a dopant of fine clay, carbon and other impurites to try and stop the slica particles from coming together and forming a chalky solid, but I have found they don&#;t help.

Does anyone have any ideas of how to fix this?



Are you making this yourself? If not, is this hydrophilic silica (like Cabosil) or hydrophobic silica?

I don&#;t make it myself, I bought the hydrophilic epoxy thickener and and the hydrophobic version. After burning both gels once, the closest I was able to get it to it&#;s original state was a gritty gel, which I made by grinding the used powder with some fuel, which isn&#;t ideal, as I don&#;t want to have to grind it everytime I use the gel.

Try using alcohol as the fuel, I think the ash is causing the clumping. Alcohol burns cleaner than kerosene or gasoline

There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.

I have tried to use alcohol as a fuel, it gives the same result, on the surface of the gel it turns white, shrinks and cracks as it burns, as the fuel evaporates. I just tried to boil water out of a gel, and it gives the same powdery solid.

I think it is like a making aerogel incorrectly, it evaporates very quickly, and the little particles get condensed as the fuel evaporates off, leaving a chalky, weak solid.


Ok then, maybe you should try adhering the particles to the surface of something else, similar to how Pd/C is made. The particles should not be able to move in that case.

There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.

That does sound like a good idea, I will have to look into doing it to improve performance. I was thinking of reacting a solution of sodium silicate with a acid over activated carbon to form Sio2 particles which I think are similar to fumed silica particles.

Should be, but don't use activated carbon, that will burn away. Maybe some high temperature polymer.

There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.

I think activated carbon will work in my case, I designed a fuel container that was a tuna can with very fine stainless steel wire mesh on top, it allowed the fuel to evaporate out, but prevented oxygen from getting in. It worked, it just had poor performance because the silica clumped after use, which this should solve.

Oh, then it should work. I thought you were just lighting a lump of the stuff on fire, not with an actual burner system.

There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.

I mixed some fumed silica with finely powdered carbon, and it didn't&#; t really work.

I mixed both in water, and then boiled the water out, at higher concentrations of carbon, it seemed to strengthen the material formed, and at lower concentrations it seemed to slightly improve it by making the solid slightly weaker and more crumbly. On the bright side, it did make a very cool navy blue pigment for some reason.

I will have to try using sodium silicate to deposit some silica on carbon next.



[Edited on 5-27- by Bestbmc]

Are you sure the fumed silica isn't simply sintering because of the heat?

He also got the same result just by soaking the silica in water and evaporating the water. Its like incorrect aerogel drying, not sintering. Also, the carbon would burn off first, before silica sintered.

There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.

I think that since the silica is contained in the water, it shrinks with the fluid as it evaporates, leaving a denser solid when the last of the water evaporates.
I don&#;t think this can be avoided, so im trying to find ways to may the solid weaker or prevent the silica particles from coming together, to make it easier to be re hydrated with a liquid. I also don&#;t think it is sintering, as it is a crumbly solid, and I didn&#;t use high temperatures.

Maybe try adding ethanol to sodium silicate. That forms a semi-solid gel that could be chemically regenerated by reacting it with NaOH and then adding ethanol.

There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.

If you are looking for more details, kindly visit silica dispersant.

In nanoparticle physics there is a relationship between solubility and curvature, where the solubility of a surface with positive (negative) curvature increases (decreases) with increasingly sharp curvature. This is due to the asymmetric probability of transport into/outfrom a curved boundary. The relationship looks like this, with c(r) being the effective solubility parameter at an interface with curvature radius r (k is a constant capturing various physical parameters):

c(r) = c(&#;)exp(k/r)

Possibly, there is a corresponding relationship between melting / glass transition / vapor pressure and curvature, with very tiny particulates having less heat tolerance than the bulk solid. While it may not "sinter", it may nonetheless ripen, leaving more large particles and fewer small ones.

https://en.wikipedia.org/wiki/Ostwald_ripening

So there is no guarantee that fumed silica can be reused, physically speaking, and there are reasons to believe it may not be possible.

[Edited on 30-5- by clearly_not_atara]



Quote: Originally posted by bnull  you can always buy new equipment but can't buy new fingers.

Yeah, I got down to my last idea of making it work today, I tried dissolving polystyrene in a lot of solvents like acetone, mineral sprits, gasoline etc, and mixing it with the silica and then evaporating the mixture to leave a power of polystyrene and fumed silica. I hoped the polymer would interfere with the silica coming together, but when I tried to gel the fuel with the powder, it worked worse than just reusing the silica.