home and hobby chemicals licensing

[Peter Fairbrother]

The UK Government is proposing to limit the concentration of acids and
some other chemicals which home users with licenses can possess to the
following:

Hydrogen Peroxide 35%
Nitric acid 10%
Sulfuric acid 40%
Chlorates and perchlorates 40%
Ammonium nitrate 16%N

Note this is with a license, without a license the concentrations are lower.

Having to get a license is one thing, but making licenses unavailable is
quite another. I am going to reply to the consultation, and so - does
anybody know of any legitimate hobby/home uses for any of these
chemicals at high concentration?

- Hydrogen peroxide at >35% is mostly the province of rocket fuel,
though 50% is used in some home chip-making techniques (yes, people do
make microchips at home - record so far is 1,200 transistors afaik).


- There are quite a few uses for strong nitric acid at above 10%:
50% passivating stainless
50% iron particle removal from machined nickel alloy parts safety critical
50%+ precious metal recovery and refining
50% unknown metal testing
70% gold test kits
86%+ (fuming) decapping microchips


- The only use I have come up with so far that needs >40% sulphuric is
for making acid pirhana solution for cleaning glass and ceramics. The
commercial 98% is undoubtedly useful for topping up baths for anodising,
electroplating and electroforming, but it could be argued that 40% is
sufficient here - not sure that is always true though, if you get in a
mess sometimes 98% is the only thing which will do.


- Chlorates and perchlorates at >40%. Chlorates were used as
weedkillers until the EU banned them on the grounds that nobody had
shown them to be safe for the environment (nobody had showed them to be
particularly dangerous either, and quite a few gardeners still swear by
sodium chlorate), but this may have actually been a reaction to the
sugar/chlorate explosive of boys pranks and more dangerous uses.

They are also used in theatrical flash mixtures and for photography.

Plus a lot of fireworks components like stars will have >40% perchlorate.


- Ammonium nitrate at >16%N ??

Peter Fairbrother