Using a Coffee Grinder to Pulverize Potassium Nitrate
If one does not have a ball mill there is another option for grinding coarse potassium nitrate into a free
flowing, fine powder. Coffee and spice grinders work well for grinding small batches of individual
Even though I have a ball mill, there are times when the coffee grinders come in handy for pulverizing
smaller batches of chemicals. I have some Parlon, most of which will pass through a 40-mesh screen, but
which has some larger particles as well. I'll take those larger bits and run them through the coffee
grinder in order to reduce them to smaller particles.
Warning: Dedicate one grinder for use on oxidizers, and another one for use on fuels such
as charcoal. We don't want fires or explosions when we're grinding chemicals. Never grind complete
or mixed compositions such as black powder in a coffee grinder.
I have found two kinds of coffee grinders: blade-grinders and burr-mills. Don't get a burr-mill; they
don't work as well as blade-grinders. The blade-grinders have a stainless steel blender type blade that
spins at high speeds in the bottom of the material cup, chopping the material into small bits in the
Blade Coffee Grinder for Pulverizing Chemicals
I have purchased many of the smaller, less expensive, blade-type coffee grinders. But here's the
warning: they really don't last too long if you mill chemicals for a minute or two at a time. To use
them, mill your chemicals in pulses of a few seconds at a time. I've found that shaking them while
pulse-grinding gives me the fastest results.
Less Expensive Blade Coffee Grinders
Grinding Potassium Nitrate with a Blade Mill
The Kitchenaid blade mill has a larger hopper, and a larger, more powerful motor, and is rated to be
used often. I'm hoping that it will last longer than the $13 WalMart models I've been using.
I put a half-cup, 4.6 ounces, of 12-mesh potassium nitrate into its hopper, pressed down
on its lid to start it, and pulse-milled the powder for just under a minute, shaking the grinder now
and then in the process.
Quite a bit of fine powder started to accumulate on the inside top of the clear lid as it milled. I
dumped the ground chemical onto my 100-mesh screen, and used a fine paint brush to clean off any that
was clinging to the inside of the hopper or the lid.
About three-fourths of this milled powder would pass through the 100 mesh screen, and I set aside
that which wouldn't to be ground again with the next batch.
Successfully Milling Potassium Nitrate with a Coffee Blade Grinder
Granular potassium nitrate can be dried if necessary, and ground easily with a ball mill or with a
coffee blade mill, so that it passes through a 100-mesh screen and is ready to be used in pyrotechnic