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nikotyna1939
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theoretical repursposing
i also just want to know is there another feasible ways to recycle concrete rubble other than Construction aggregate and fillings
[Edited on 18-3-2024 by nikotyna1939]
[Edited on 18-3-2024 by nikotyna1939]
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bnull
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Fertilizer. Concrete is rich in calcium (of course), magnesium, and iron, and is a source of silicon for rice and other cultures. It can also be used
to adjust the pH of soil.
[Edited on 18-3-2024 by bnull]
Quod scripsi, scripsi.
B. N. Ull
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nikotyna1939
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Calcium chloride + silica= product ?
what is the main product of reacting Calcium chloride + silica at room tempreature in water ?
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nikotyna1939
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very useful products
i meant other very high valued useful products for recycling
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bnull
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Silica is sparingly soluble in water (about 120mg/L). The best case scenario is a light coat of calcium silicate of indefinite composition on the
silica particles. It will take years to make an usable quantity of CaxSiyOz.
Let me guess: you have a huge pile of rubble lying in your backyard and you want to make money with it. Forget it. Concrete recycling is only
economically viable for the industry.
Unless you want to work in landscape designing.
[Edited on 18-3-2024 by bnull]
Quod scripsi, scripsi.
B. N. Ull
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Admagistr
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Quote: Originally posted by bnull  |
Silica is sparingly soluble in water (about 120mg/L). The best case scenario is a light coat of calcium silicate of indefinite composition on the
silica particles. It will take years to make an usable quantity of CaxSiyOz.
I'm afraid it would take millions of years for a chemical reaction to take place between SiO2 and CaCl2 in H2O at room temperature, and maybe even
that wouldn't be enough |
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nikotyna1939
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Preparation of Calcium Silicate from Calcium Chloride and Silica ?
What is the simple and fastest ways to prepare Calcium Silicate from Calcium Chloride and Silica for about 10 grams ?
[Edited on 20-3-2024 by nikotyna1939]
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Admagistr
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| Quote: Originally posted by nikotyna1939 | What is the simple and fastest ways to prepare Calcium Silicate from Calcium Chloride and Silic Acid for about 10 grams ?
[Edited on 20-3-2024 by nikotyna1939] |
That's not the way... Silicic acid is a very weak acid that cannot easily displace HCl. You'd need extremely high temperatures for that to happen! And
you might as well use SiO2...I mean, it's nonsense.
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Admagistr
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A small amount of pure calcium silicate is better to buy It is sold, for example,
as a pharmaceutical raw material. For example, here: https://www.drhoffmann.cz/kremicitan-vapenaty-cisty-id262.ht...
Although here this company does not sell it cheap...I believe you can find a seller who sells pure CaSiO3 in small quantities cheaply...
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nikotyna1939
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temperature for preparing calcium silicate from calcium chloride and silica?
at what temperature do i need for preparing calcium silicate from calcium chloride and silica in 5 minutes?
[Edited on 20-3-2024 by nikotyna1939]
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Precipitates
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If you have some caustic soda (sodium hydroxide) drain cleaner lying around, the following is a viable route:
Sodium Hydroxide + Silicic Acid -> Sodium Silicate
Sodium Silicate + Calcium Chloride -> Calcium Silicate (precipitate) + Sodium Chloride
The Alkali-Silica Reaction (ASR), otherwise known as concrete cancer, covers the first reaction. Given your interest in obtaining calcium silicate,
the end product of these reactions, it's probably good reading material:
https://en.wikipedia.org/wiki/Alkali%E2%80%93silica_reaction
Silica can replace silicic acid:
https://www.youtube.com/watch?v=xltvwhogklI
but be very careful when heating the sodium hydroxide solution (hot concentrated NaOH solutions are dangerous).
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Precipitates
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| Quote: Originally posted by nikotyna1939 | at what temperature do i need for preparing calcium silicate from calcium chloride and silica in 5 minutes?
[Edited on 20-3-2024 by nikotyna1939] |
I'm not sure if calcium silicate is formed, but these are the kind of temperatures you need to decompose calcium chloride in the presence of silica:
873K to 1143K
https://www.jstage.jst.go.jp/article/kakoronbunshu1975/9/5/9...
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bnull
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In 5 minutes, starting from calcium chloride and silica? No. The only way to make calcium silicate (of uncertain composition) in 5 minutes or less is
by mixing a solution of calcium chloride (or other soluble calcium salt) with a solution of sodium silicate.
Silica is reasonably inert, forms a weak acid and won't displace the chlorine either in solution at ambient temperature or at high temperatures. In
the paper pointed by @Precipitates, it is oxygen (or steam) what displaces the chlorine, with silica acting as a catalyst.
It's more like CaO diffused in silica, which takes us back to @Admagistr's suggestion of heating the mixture above 1400 °C.
What bothers me is that, when performed under oxygen atmosphere or air, one of the products is chlorine. For a small quantity, say, 5 g of calcium
chloride plus silica, the amount of chlorine is (let's say) safe to handle.
Quod scripsi, scripsi.
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Admagistr
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| Quote: Originally posted by bnull | In 5 minutes, starting from calcium chloride and silica? No. The only way to make calcium silicate (of uncertain composition) in 5 minutes or less is
by mixing a solution of calcium chloride (or other soluble calcium salt) with a solution of sodium silicate.
Silica is reasonably inert, forms a weak acid and won't displace the chlorine either in solution at ambient temperature or at high temperatures. In
the paper pointed by @Precipitates, it is oxygen (or steam) what displaces the chlorine, with silica acting as a catalyst.
It's more like CaO diffused in silica, which takes us back to @Admagistr's suggestion of heating the mixture above 1400 °C.
What bothers me is that, when performed under oxygen atmosphere or air, one of the products is chlorine. For a small quantity, say, 5 g of calcium
chloride plus silica, the amount of chlorine is (let's say) safe to handle. |
Good analysis of the problem and you explained it nicely !
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