Silica gels absorb moisture. I intend to use silica gels as fire retardants. My question is - Is it possible to chemically alter silica gels to release water content when in contact with fire, thus suppressing the fire?

Here's my idea. Since silica gels are essentially silicon dioxides and since they are tetrahedral in nature, replacing some of the silicon atoms with carbon atom will produce carbon dioxide which is useful in putting out fires.

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    $\begingroup$ "replacing some of the silicon atoms with carbon" How do you plan to do that? If everything was that easy I would've made diamonds out of the dirt in kitchen. $\endgroup$ – M.A.R. Jan 10 '16 at 8:30
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    $\begingroup$ You don't have to alter silica gel to make it release its water content upon heating. It already does that. Carbon dioxide is another story, though. $\endgroup$ – Ivan Neretin Jan 10 '16 at 12:31
  • $\begingroup$ Gypsum wallboard soled this problem a long time ago. $\endgroup$ – Jon Custer Jan 10 '16 at 16:03

Silica gel would be a bad fire retardant. You do not need to modify it to make it release water in fire: it happens on itself. The reason water works well to put out fires is because of its endothermic vaporisation. When you put liquid water in fire it vaporises and takes a lot of heat from the fire. Silica gel can only absorb a certain amount of water which is not that much. You will need a lot of silica gel, so much it will become impractical.

Yes, silica is tetrahedral but you can't just replace silicon with carbon. It does not work like this. Carbon oxides are gaseous, not solid like silica. The reason why carbon dioxide works against fires is that it's not oxygen, so that suppresses a critical component for fires. Even if you could store somehow carbon in solid dioxide, there will not be enough to actually do anything.


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