Sciencemadness Discussion Board

Calcium / iron fluoride into lead fluoride

Fantasma4500 - 14-9-2020 at 11:40

so, i have a huge source of fluoride at my work: flux
its used in welding and it cleans off the surface of the steel while welding, of what i can see its typically calcium fluoride used as flux, anyhow some of it ends up as iron fluoride too, now since i realized you can dissolve lead metal with acetic acid and hydrogen peroxide i thought, why not make a bunch of lead fluoride? but im stuck- i dont want to make HF, not turning the fluoride into a volatile and yet getting it to stick with lead, am i on an impossible mission?

i couldnt find much on NaOH + CaF2, so i went ahead and tried using some flux pieces with NaOH on hotplate with water. i let it heat up well so it was eventually just molten NaOH thereafter i acidified the whole mixture assuming HF would be stronger than acetic acid (i remember years back trying to find out if HF was stronger than HAc but didnt find anything) and once i mixed lead acetate with the acetic acid mix i got no precipitate

the NaOH solution did turn quite brown, but assuming most of whats in the slag isnt actually iron hydroxide-carbonate etc where the hell did the fluoride go? lead fluoride is very insoluble

chemist1243 - 17-10-2020 at 14:29

First of all, I dont think flux is PURE fluoride salt. Look up the MSDS for the flux you’re using and isolate out the fluoride salts based on the data. Next, try reacting a solution of Lead nitrate with your fluoride salt. Wikipedia says it works using KF, so your best shot is this method. Alkaline earth metals dont have the exact same properties as the alkali metas, so no promises, but just give it a go update us on how it went.

Remember to always keep calcium gluconate on hand even when only working with fluoride salts, because fluoride salts still react with water to form small amounts of HF.

Good luck! (:

https://en.m.wikipedia.org/wiki/Lead(II)_fluoride