amorphous silica (diatomaceous earth) dissolution and precipitation using household bleach or ammonia [closed]








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I'm a layman not a chemist. My question is whether it's possible to dissolve amorphous silica in room temperature water mixed with a commonly available alkaline household product and then have it precipitate naturally out of solution over a few days or weeks. To dissolve a kilo of amorphous silica, what would be the right amount of over-the-counter laundry bleach or household ammonia and room temperature water?


I'm looking for a way to prevent nests of tiny stinging red fire ants under patio pavers that will be laid on sand and jointed with sand. Diatomaceous earth (amorphous silica) is said to be fatal to ants when they come into contact with it, so I wondered if spraying the screeded sand underlayment *in situ* and also the sand in the joints until it was quite wet with the diatomaceous earth solution might do the trick.


I also thought it would pose [a lower health risk](https://pubmed.ncbi.nlm.nih.gov/11876495/) and involve much less discomfort to mix up a batch while wearing a respirator and gloves than to work with the diatomaceous earth in powder form, mixing it dry with the sand, over the several weeks it will take me to lay the pavers.




Once it's been [wet, diatomaceous earth is less effective](https://gardenerspath.com/how-to/disease-and-pests/diatomaceous-earth/), so putting it into water, even as a suspension, defeats it's purpose. For that matter, it needs to be reapplied if wet by rain or damp earth. According to [BugTech](https://www.bugtech.com/diatomaceous-earth-benefits-as-a-natural-pesticide/), "sharp edges make tiny cuts in an insect’s exoskeleton upon contact, and the diatomaceous earth then absorbs the oils and fats from its outer layer." If the silica is wet, it will hydrophilic, not oleophilic, and would not absorb oils.


Non-chemistry suggestion: disperse it with air. Use an old container from "talcum" (now starch, for safety) powder, or a container for boric acid insecticide. These squeeze containers are designed to spray out the powder, propelled by air. Diatomaceous earth is [sold in air-spray bottles](https://rads.stackoverflow.com/amzn/click/com/B06X952WC5), too. It *might* be feasible to use a sandblasting gun on large areas, with proper respirator -- though at the risk of silicosis.


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