18 replies to this topic

[Peret]

talking about round bar, i did reading a description of a "bar mill" where the media was indeed a collection of round bars just under the length of the milling jar i wonder how effective these are?

Bar mills (or rod mills) are extremely effective crushers - I've seen a fair number of these rusting away at abandoned mines around here. The principle is that rods can't approach each other more closely than the largest particle between them, so they preferentially work the largest pieces first and work down until everything comes out a uniform size. The ones I've seen are riveted iron cylinders 4 feet in diameter and 8 feet long, 1/3 filled with full length mixed iron rods from 1 inch to 3 inches diameter, turned by a car engine. A mill that size can reduce a ton of fist-size rocks to fine sand in a few hours. I tried making a small one one, but unfortunately the technology doesn't scale - with a table-top mill the rods just are not heavy enough. Also, the reason they're preferred to ball mills is that they don't grind the ore all the way to dust. When fine powder is required, like for gypsum (plaster), ball mills still rule.

[Mumbles]

I've always heard the term "cylpeb" thrown around for cylinders that are as long as they are wide.

Rod mills do scale to table top models. I ran one with lead filled copper pipe. It works okay for crushing charcoal from lump down to a granular material. Not as efficient on prilled KNO3. Ultimately I can grind my charcoal faster with a blender than a rod mill will do.

[digger]

That would be very nice of you.

It has been a while since I offered this. It is my first day back in the office, so please find the file below. It may not have every bit of infor that you need, but there are plenty of references to other work.

Clicky Clicky

Edited by digger, 01 June 2010 - 10:25 AM.

[Potassium chlorate]

Thank you very much!