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mleku
1w ago
yes, calcium hydroxide (quicklime) aggressively binds to hydrofluoric acid and becomes insoluble
this same mechanism also is what happens with skeletal fluorosis, which happens with excess fluoride intake. calcium fluoride is less soluble than calcium triphosphate, which is the main mineral in bones
this same mechanism also is what happens with skeletal fluorosis, which happens with excess fluoride intake. calcium fluoride is less soluble than calcium triphosphate, which is the main mineral in bones
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mleku
@mleku
1w ago
the reason for the different results at different temperatures is that at sufficiently high temperatures the phosphoric acid in the calcium triphosphate dissociates as elemental phosphorus and boils off... note that this has other possibly unwanted effects like forming phosphine gas and thus it's important to ventilate the furnace well if you are calcining bones like this.
also note that as well as being great at capturing fluoride you can directly use this with sodium/potassium silicate to make concrete
also note that as well as being great at capturing fluoride you can directly use this with sodium/potassium silicate to make concrete
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mleku
@mleku
1w ago
yeah, not sure if that was clear... with too little oxygen the phosphorus may form a dangerous amount of phosphine gas which causes lung failure and can explode easily.
this is what causes bog fires, also, and it doesn't even really take that much heat to do it, but at a certain temperature phosphine just catches fire, this is how safety matches work (the red stuff on the side of the box is partly a form of phosphorus called red phosphorus and the match head contains a friction sensitive oxidiser called potassium perchlorate, so when you rub the two together, the phosphine ignites and kicks off the perchlorate which then lights your match
this is what causes bog fires, also, and it doesn't even really take that much heat to do it, but at a certain temperature phosphine just catches fire, this is how safety matches work (the red stuff on the side of the box is partly a form of phosphorus called red phosphorus and the match head contains a friction sensitive oxidiser called potassium perchlorate, so when you rub the two together, the phosphine ignites and kicks off the perchlorate which then lights your match
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Tim
@Tim
1w ago
It was done in my woodstove and vented outside.
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mleku
@mleku
1w ago
phosphorus is gnarly stuff tho, ngl
if you ever want to mess with it (be careful) you can manufacture it by collecting and dehydrating pee, which has a lot of phosphoric acid in it, to refine it you need to exclude oxygen, and at different temperatures it goes from white to red to black and has different properties
i can't think off the top of my head what uses it has other than making phosphoric acid, which is good for dissolving iron oxide, and red phosphorus which is good for making safety matches
most industrial production starts from mineral deposits of phosphate so when i say it can catch fire, i mean, really, in your simple calcining setup it's unlikely to be bad unless it vents into an unventilated space
if you ever want to mess with it (be careful) you can manufacture it by collecting and dehydrating pee, which has a lot of phosphoric acid in it, to refine it you need to exclude oxygen, and at different temperatures it goes from white to red to black and has different properties
i can't think off the top of my head what uses it has other than making phosphoric acid, which is good for dissolving iron oxide, and red phosphorus which is good for making safety matches
most industrial production starts from mineral deposits of phosphate so when i say it can catch fire, i mean, really, in your simple calcining setup it's unlikely to be bad unless it vents into an unventilated space
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Troy
@Troy
1w ago
Black powder
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