You did not specify the tonnage or feed size. There are a number of milling systems. I'll pick one.

Micro Grinding Systems

1823 East 17th Street

Little Rock, Arkansas 72202

(501) 374-8402

http://www.microgrind.com/

Lawrence Nordell

Conveyor Dynamics, Inc. ■

You are looking for the near impossible with the proviso to be both feasible and cost effective.

The reduction stage is about 50000 micron to 1 micron. A typical reduction stage of crushing or milling equipment ranges in the neighborhood of 6:1 in a single pass and can be increased with increased recirculating load. This assumes the measurement is tied to P80.

I recommend you read: "Mineral Comminution Circuits Their Operation and Optimisation" produced and published by JKMRC as a part of Queensland Univ. in Brisbane Australia. Look to JK Tech their commercial arm.

Also look to cement milling, but on a small scale to see how to get down to one micron. There are a class of milling machines called micronizers, and nutation mills that grind material to facial powders, paint additives, lubrication additives, and fine fillers for polymers and the like.

Consider wear and power.

If Rittinger is right, this is going to take 500-1000 kw-hrs/ton. You are in the realm of state-of the art and experimental machines.

I work in the scale from 1500mm to 100 microns. One micron is a little out of my league.

I thought you might not get to many responses. I am trying to give a little insight.

Lawrence Nordell

Conveyor Dynamics, Inc.

www.conveyor-dynamics.com ■

You might try:

http://www.ecutec.es/grinding.htm

LKN ■

I support Mr. Nordell's comments on this subject, as well as your own observation that pre-grinding changes the picture.

As I see it, the process specification is unrealistic. Having been intimately involved in this field, I do not believe there is a single process unit capable of perfoming the task as specified.

From your description, your client desires a dry grinding process. I could discuss this at length, but at a grind size of 1 micron, there is no single commercial machine that can operate at 2 tph.

It is possible to dry grind to the desired size if the starting material is around 200 microns, but there are numerous problems to be overcome.

Dry grinding at this size typically requires a stirred ball mill. These come in two forms: air swept and direct. The problem with an air swept mill is the classification step. You will not be able to classify ground glass at 1 micron. For one thing, it will have enormous surface energy through mechano-chemical activation.

A direct grinding mill will suffer heat build-up. This limits it's physical size and therefore throughput. At best, even with the largest mills available, multiple units would be required. Significant capital costs would be involved. Numerous processing issues also arise.

Wet grinding at the energy inputs suggested is possible, but this implies multiple process steps. including drying at least. Also, I suspect that glass dissolution will occur.

I suggest that the specification needs to be relaxed. Options are numerous, depending on the process objectives.

If you would like to discuss this further, please feel free to contact me through this forum. ■

We are specialised on fine grinding and micronising, and we find this kind of processes very often.

We probably would propose a ball mill (maybe Al2O3 protected against abrasion) and a classifying circuit. We have classifiers cutting at 98%<3µm, so I think we could reach your customer's requierements.

Rought information at: www.ecutec.de or www.ecutec.es , and please do not hesitate to contact us for further details.

Best regards to all,

lex Farreras

Ind. Eng.

a.farreras@ecutec.es ■

Dr. Sundar

Perhaps you might like to provide the forum with some details about yourself and your company? This might prevent people wasting your time as well as their own.

For example, including a site address with your signature file, or in your profile would be useful.

Something like this one, for example:

http://www.fasc.net/Applications.htm ■