Talk:Silica gel

Misc

Use is now illegal in EU at least it's 'casual' use in packing of products —Preceding unsigned comment added by 194.159.128.254 (talk) 11:29, 24 February 2011 (UTC)

Incorrect - I think you have confused it with something else: see http://www.ga-uk.org/article.aspx?articleid=123321 Wikimike2007 (talk) 17:42, 26 May 2011 (UTC)

I got this when I buy computer hard disk. I always wondered what it was... :D

Gel?

In layman's terms, Silica Gel isn't a gel. Even by the definition on gel, it doesn't seem to be quite a gel. Xerogel says silica gel is a xerogel, although it's a small page with few edits. Colloid makes it sound like xerogel means "solid foam", which may be what silica gel is.

So what is it? Is silica gel a dehydrated gel like aerogel, or is it a regular gel where the solid component is just very hard? ―BenFrantzDale 03:45, 10 February 2006 (UTC)

Anybody? What definition of "gel" does this fit? —Ben FrantzDale (talk) 13:32, 24 April 2012 (UTC)

Causes cancer?

minor grammatical problem but...under "properties" heading, second paragraph, it says "...cobalt (II) chloride, a chemical that is known to cause cancer and change color when moist." It causes cancer when it gets wet? reword to "...cobalt (II) chloride, a chemical that changes color when moist. It has also been shown to cause cancer." or something like that. random regular visitor, 19:26, 26 February 2006 (UTC)

--The word Carcenegenic (sp) might also be gramaticly correct... —Preceding unsigned comment added by 217.243.200.234 (talk) 13:34, 23 January 2008 (UTC)

Carcinogenic Drjehr (talk) 15:31, 20 June 2021 (UTC)

Eating Silica Gel

What happens when you eat it? Because I sure looked up this page to see what would happen if you eat it. IMFromKathlene 01:45, 8 July 2006 (UTC)

I've always wondered too... Regardless, I have eaten some, and I'm still alive today, so I guess it's not extremely fatal. Hispanic! At the disco 21:26, 8 July 2006 (UTC)Silvernich

You really ate some??? crazey dude! lol...I think they should dye these dark blue- or red- my puppy found a packet in some wrapping---he tore open the packet- and we heard tiny balls rolling round our wooden floor- prob is you cant bloo*y see them!!! They are clear and so almost invisable- the makers have a responsibility to make these 'safe' in any situation- so DYE them for the love of dog!

Did your puppy eat any or have any problems that may have been linked to it? I'm pretty sure my puppy ate some. He has thrown up and been lathargic for about14 hours now. Not sure what to do.

The small pellets may crack when enough moisture is absorbed. If they crack in your stomach, it'll be like tiny pieces of broken glass in your guts. Not recommended ;) --85.156.246.23 17:27, 24 December 2006 (UTC)

I would say that the fact that they can shatter is a bit more dangerous than any "poison" they contain; it IS kind of like broken glass or sand, and if you chew on a piece and break it and have all the little bits and pieces irritate your mouth, you'll probably not try it again.... -129.21.96.59 08:52, 29 January 2007 (UTC)

DO NOT EAT

This warning is so strange, I mean, you don't get this warning on batteries, gun powder, ink cartriges, boxes of nails etc... Those are just the first things that came into my head. I mean I'm not so interested as to what would happen if you ate them, although this would be interesting, I always just presumed it would absorb the water in your stomach/wherever. What I want to know is why does silica gel have this warning in big upper case letters whereas far more dangerous things that you're just as unlikey to eat don't. --Aceizace 22:48, 25 September 2006 (UTC)

I'm guessing because to the untrained eye they may look just like sachets of sugar or salt. One person I know had a packet of Chinese food containing a sachet of silica gel without the written warning (just a vague diagram that might have looked like a warning not to eat it), and thought it was a dressing of some kind. And then wondered why the food tasted foul. Stannered 20:52, 12 November 2006 (UTC)

Batteries, gun powder, ink carridges, and boxes of nails are not often included in packages of food. Capsules or sachets of silica gel, on the other hand, often are found in containers of food and drugs.71.199.121.113 (talk) 18:04, 7 August 2009 (UTC)

Production

How is it made? —The preceding unsigned comment was added by 203.0.101.131 (talk) 03:23, 18 April 2007 (UTC).

Why even use the stuff?

If it's potentially toxic, why do I find this stuff hidden in just about every consumer good? Wouldn't rice do the same job of absorbing moisture?

Silica gel by itself is non-toxic. The sachets in food items and pharmaceuticals do not contain any potentially poisonous dopants like the cobalt (II) chloride moisture indicator, so they're not a problem. They're used instead of rice because of cost, and because they absorb much more moisture than grains of rice. 97.82.247.200 18:57, 2 September 2007 (UTC)

Also, silica gel does not germinate or spoil, unlike rice.RSido (talk) 04:12, 11 December 2007 (UTC)

Silica Sand and purity?

Most brands of silica gel cat litter (I'll use Food lion, for example) appear to be 100% silica gel, however in the case of the Food Lion product, the ingredients are: "silica sand, oxygen and water". That raises a few questions.

1) If the purpose of the product is to absorb moisture, why include water? Is that just the manufacturer's way of saying the product has already naturally absorbed trace moisture during packaging?

2) Is silica sand really the same thing as silica gel? Both terms are used interchangeably on the packaging.

3) Given that the ingredients list only silica sand, oxygen and water, why are some crystals vividly dark blue? That would seem to imply some kind of dopant, yet the blue crystals don't change color when wet, so it isn't a moisture indicator. I doubt this color is naturally occurring, so what is it? An unlisted color for litter box aesthetics, a chemical added for antibacterial properties, or something else? 97.82.247.200 19:08, 2 September 2007 (UTC)

Chemical formula?

I'm confused. This article states: silica gel is made from Na₂SiO₃ - sodium silicate. The sodium silicate article states In acidic solutions, the silicate ion reacts with hydrogen ions to form silicic acid, which when heated and roasted forms silica gel,, while the silicic acid article states Silicic acids are formed by acidification of sodium silicate in aqueous solution. When heated they lose water to form silica gel, an active form of silicon dioxide.. Neither article lists the actual chemical formula for silica gel. Only the previous blurb in the silicic acid article comes close. Thus, it remains unclear what the actual chemical formula is. My guess from the silicic acid line would be: SiO₂. Either way, the formula should be clearly mentioned in this article, and the other articles edited to fix that ambiguity. 97.82.247.200 23:43, 2 September 2007 (UTC)

Good question. I came here wondering if I could use silica gel in a reaction instead of sodium silicate. The article (now) sounds like it doesn't clearly know: "Silica gel is a granular, vitreous, highly porous form of silica made synthetically from sodium silicate." "Synthesized" would be much clearer than "made synthetically." So is it sodium silicate or not? From Preparation section, I'm thinking no, but the formula would make it much clearer. 18.55.0.66 (talk) 21:03, 17 August 2010 (UTC)

suggested changes to preparation

Silica gel is made from sodium silicate. Silicic acid is released from sodium silicate with hydrochloric acid and the remaining material forms a gel that consists of polymer aggregate spheres when water is eliminated. The gel is dried to form hydrogel and heated to form hard xerogel that is ground to produce the silica gel product. Ammonium tetrachlorocobaltate or cobalt chloride is added when a water absorption indicator is needed, making the gel blue when dry and pink when saturated. [1] --John Bessa (talk) 14:44, 15 November 2010 (UTC)

Absorbtion

Anyone have any data on how much water silica can absorb per weight? StarkyD (talk) 18:34, 23 May 2008 (UTC)

Also any info available on the relationship between equilibrium Air RH, temperature and silica gel water content? I want to design an air dryer but cannot find any data.(Minding Baby (talk) 00:04, 20 October 2008 (UTC))

Surface Area

Is the surface area really 800m2/g as stated in the article? Maybe I'm missing something here, but that's huge!

Yes. That's why it is used. --Jaded-view (talk) 05:34, 1 August 2008 (UTC)

I think the previous person meant that this should probably be explained somewhere, because it does look like a rather large amount. Could someone please explain this? Is it because it's incredibly light, or does it actually have a larger surface area when viewed under a microscope than it appears to the naked eye? Thanks, Rocker1982 (talk) 09:25, 10 April 2009 (UTC)

Think cube of side length D, drilled with billions of holes, clearly each hole will remove twice pi*r^2 for the ends of the cylindrical hole and add 2*pi*r*d for the side of the cylindrical hole. --24.148.80.51 (talk) 08:33, 23 April 2013 (UTC)

What?

"Silica in this form can be a cost effective way for retail consumers easily to purchase silica gel...." This doesn't make any sense. Svanslyck (talk) 12:43, 26 September 2011 (UTC)

"Given the water adsorption properties of silica gel, it is used in domestic water filters such as the commercialized brand ZeroWater. The surface structure of silica gel allows the adsorption of some minerals which are dissolved in the water,[10] or "Ion-exchange" as it is marketed, the lack of regulations for domestic water filtration products, there are no studies which validate the manufacturer claims regarding the effectiveness of the filtration system." This doesn't make sense, the section is about how silica gel can be used for water filtration but the only example is of a company that has unverified results. Leaves the reader extremely unclear as to whether or not it is actually useful for water filtration.

Syntax Question

I apologize if this is not something that should be posted. I blame it on my ADD/OCD. I am unable to follow the logic in the following sentence: "Because silica gel can have added chemical indicators (see below) and absorbs moisture very well, silica gel packets usually bear warnings for the user not to eat the contents." Why does it have to be labeled with a warning because it 1.) Changes Colors and/or 2.) Absorbs moisture very well? "I" am not sure what one has to do with the other. My schema is far from the normal so I present this for your review. If this is not an appropriate topic to post here, please notify me so I may cease. Thanks 174.56.209.94 (talk) 09:24, 25 November 2013 (UTC)modgod

Citation Needed by 138.131.217.134

> literature indicates that most French, German, and American gas mask canisters used carbon from wood and later fruit pits or nuts, not Silica Gel as the adsorbent

\ | - | / | - | \ | - | / (talk) 16:46, 17 July 2015 (UTC)

Natural or synthetic?

The first sentence says "Silica gel is ... a form of silicon dioxide made synthetically from sodium silicate" while third sentence says "It is a naturally occurring mineral that is purified". Assuming the "It" in the third sentence is "silica gel", these two sentences seem contradictory -- either it's synthesized or it's naturally occuring. Was something edited away, creating the contradiction? --Jhfrontz (talk) 13:54, 24 July 2015 (UTC)

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Article abstract

The article abstract say nothing about its use.--Juandev (talk) 19:28, 5 September 2017 (UTC)

properties?

i miss info on properties like melting temperature, etc. 89.134.199.32 (talk) 11:13, 5 January 2021 (UTC).