Making Potassium SIlicate Solution

[Tamalero]

Hi everybody


I’m trying to make my own potassium silicate solution. Yesterday i bought in a chemistry store this potassium silicate.





But when i try to dissolve it in hot water, the potassium silicate still insoluble.

This is a solubility experiment.

pH water before PS 7.1

pH after put PS into water 10.7




I break the rock to help it dissolve, but still no dissolve.

Someone has been experimenting with PS solutions?. Any idea?

Thanks!

 

[Tamalero]

I think that the pH change is a signal that a little part of PS was dissolved.

 

[Psyco G]

Can't you mix it with alcohols and water then evaporate off the alcohol? I'm not sure if that will work?

 

[MostlyMe]

Heating or even boiling the water will help dissolve it. I'd use ceramic pans if you have one, as the resulting hot solution could be corrosive.

 

[sanjuan]

The K2SO3 will precipitate with any Ca in the water, I've heard. Probably not your problem but are you using RO or distilled water?

Thanks for trying this, I was thinking of doing that but the covenience of Pro-Tekt got me.

"Agsil 16 H (Potassium Silicate)

Now you can make your own DynaGro ProTekt or silica product for pennies on the gallon! 560 grams of Agsil 16 in 1 gallon will give you 7.6% silicon (SiO2), which is the % in Dynagro ProTekt.

For foliar application, we recommend mixing AgSil 16H with Ahimsa Neem Oil.

Mix 1.5 grams AgSil 16H with 1 ounce Neem Oil to emulsify the oil. Then mix this emulsified oil with one gallon final volume spray solution. Spray every other week covering all plant surfaces (top and bottom of leaves) until it runs off.

NOTE: Never mix concentrated silica solutions with other concentrated fertilizers. It is best to make up the liquid solution first or add water prior to mixing the powder with other ingredients or nutrients."

 

[Tamalero]

Psyco G. Thanks for your suggestion. I do the experiment with 96 % ethanol, but apparently the silicatum is not soluble in alcohols.



MostlyMe. Thanks man. I boiled during 10 min the PS into 75 ml of water. The final volume was 50 ml. It helps a little to dissolve the PS, but the rock still insoluble.

It's curious that the final pH again is 10.7.

I have seen differents commercial PS solutions where the pH is 11.3

Maybe the solubility of PS in water is too little to dissolve it completely?

 

[Tamalero]

San Juan thanks for advice!. I used my tap water for the experiment. Although the water here is very soft, i will repeat the experiment again with distilled water.

Later i will show the results.

Thanks for the help

 

[Tamalero]

well i find this info about PS.

Characterization​

Composition (variable):
K2Si2O5 – K2Si2O2

Physical Properties:
Molecular weight: variable

Appearance: Fine powder, may be dissolved in aqueous solution.
Color: Solid is colorless to yellowish; solution

pH ≈11.3

Solubility: 120mg SiO2 as Si(OH)4 per liter. Very slowly soluble in cold water, increasingly soluble in water with increasing temperature. Agricultural preparations are soluble in all proportions. Insoluble in alcohol.

Stability: Stable under all conditions of use and storage.
Hazardous Polymerization: Will not occur.

 

[G.O. Joe]

It's soluble but difficult to dissolve. Boiling in just water may give you KOH (K2CO3 in air) and SiO2 instead.

Try it in a pressure cooker and only enough water in with the salt to give a concentrated solution, if it dissolved. That still might not be hot enough.

 

[noreason]

Is it necessary to get a solution and not only a suspension? Are the roots not capable of getting suspended and inert molecules?

I would start to think about this...

 

[Tamalero]

G.O. Joe: Thanks for the contribution!. So, its necessary very hot water to dissolve it , but no boiling?. Have you more information about of conversion of K2SiO3 in KOH and SiO2?. Its possible get K2CO3 in air ? the melting point its very high (891 °C).

noreason: Thanks man. i was thinking the same, i have no idea about of K2SiO3 transformation, but i find that:

Silicon is the second most abundant element in the earth’s crust, and hence is plentiful in most soils. Soluble silica
concentrations in soil generally range from 30-40 mg SiO2 per liter and are dominated by monosilicic acid, Si(OH)4

Crop plants differ greatly in their ability to take up silicon. Silica is absorbed by plants as silicic acid.....

Source: http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5057629

Other info.

Crystalline silicates like sodium metasilicate are readily soluble in water. Amorphous silicate
glasses are only slightly attacked by water at ambient temperatures. They can be solubilised only at
elevated temperature and pressure (ca. 150 °C and > 5 bar). The solutions are infinitely dilutable
with water. Silicate powders obtained by water evaporation from silicate solutions are readily
soluble in water. The water solubility depends on the pH. Above a pH of 11 - 12 stable solutions of
monomeric and polymeric silicate ions exist. The soluble content rapidly decreases when the pH is
lowered to 9. Below pH 9 only a small proportion is present as soluble monomeric silicate ions, the
majority existing as insoluble amorphous silica gel.

Source: http://www.inchem.org/documents/sids/sids/SolubleSilicates.pdf

 

[G.O. Joe]

G.O. Joe: Thanks for the contribution!. So, its necessary very hot water to dissolve it , but no boiling?. Have you more information about of conversion of K2SiO3 in KOH and SiO2?. Its possible get K2CO3 in air ? the melting point its very high (891 °C).

Concentrated solutions can be strongly heated. Dilute solutions hydrolyze, polymerize, and precipitate silica. Very dilute solutions do this at room temperature. KOH solutions absorb carbon dioxide from air.

 

[sanjuan]

I think you found the key factor here, Tamalero: "Agricultural preparations are soluble in all proportions."

http://www.pqcorp.com/Portals/1/lit/AgSil brochure 6-11.pdf

AgSil 16H is 14.8% H2O; hydrous powder.

 

[MostlyMe]

What concentration are you aiming for? Seems to me silicates are the kind of thing you might want to supply in the ppm range to your plants. The stock solution you are making can be more concentrated, say a 1000 times more, but you still might not need much to dissolve.

 

[GrowerGoneWild]

This might help..

Talks about solubility, production.. etc. might be helpful.

http://www.pqcorp.com/Portals/1/docs/Sodium and Potassium silicates brochure ENG oct 2004.pdf

 

[UNREGISTRD]

We mix agisil16 with Ro water and have no problems with solubility...

Im pretty sure it could just be the type of salt you bought..