Old Chemicals

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My grandfather (an avid photographer for the better part of the last century) has come across some old chemicals bequeathed to him some years ago. Most of them are identifiable in old developer recipes but one still puzzles us. It is a still sealed glass bottle of sodium silicofluoride (Na2SiF6) from Merch chemicals in germany (it it probably from around 1950). I've looked this up on various chemical websites (www.chemfinder.com for example) but none have any information on how it could be used. Although I did find another name for it disodium hexafluorosilicate. Any information on this subject would be much appreciated.

-- Rabbit (whiterabbitesq@hotmail.com), July 16, 2001


It is also known as fluorosilicic acid, and is one of two compounds approved in the UK for fluoridation of public water supplies. I am not aware of any photographic use for this chemical.

-- Ed Buffaloe (edb@unblinkingeye.com), July 20, 2001.


This fluosilicate stuff is TOXIC. I worked with it 35 years ago and am stil suffereing throat ravages because of it. Call a toxic disposal centre at your municipal sewage/waste teatment facility and tell them about it. It ultimately results in hydrofluoric acid which is dealy and is the only stuff that dissolves glass when mixed with water, first making hydrofluosilic acid-H2SiF6= POISON!!! Do not open the bottle or you may die if you inhale the dust. Was you grandfather into glass blowing or etching? That is the only logical reason one would have this. It was also used as rat poison in those days.

Failing that, you can mix it with some Calcium Hydroxide or lime all in equal quantities, then dig a big hole in the ground somewhere away from flowing water and bury it. The calcium and minerals in the earth will gradually detox it, but make sure there are no farms around or any way it can get into a river. If you do this, make sure to wear a good respirator and throw the respirator down the hole after the mix.

What are some of the other chemicals?

Good Luck

-- RICHARD ILOMAKI (richardjx@hotmail.com), September 06, 2001.

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