Grinding & Classification Circuits

Grinding & Classification Circuits

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Laboratory Grinding Mill Scaleup (1 reply)

Zander Barcalow
8 years ago
Zander Barcalow 8 years ago

A laboratory grindability test made in closed circuit! Should it be regarded as a miniature of a commercial mill operation? Should its performance be scaled-up to the size of a commercial mill?
Does the screen analysis of its product and circulating load resemble those of commercial mill?

O
Obersturmbann
8 years ago
Obersturmbann 8 years ago
Like

In general, the closed-loop tests are laborious and time consuming. The grinding environment within the ball mill is a first complicating factor for the scale-up. The type of classification used, have their own efficiency. For example, if the test uses cyclones and you use a very large APEX, its circulation load may be very large. If utilize conventional sieve, its efficiency is very poor (compared to a Derrick screen, for example). In such cases, try to set the minimum circulating loads possible, because after the mill scale-up, are the pump and the cyclone (namely the aspects of the hydraulic circuit) those that will command the mill.

On the positive side, when using the F80, P80, RPM mill pilot, internal diameter and length, etc. may determine the oWi (operating work index), which much more representative than Wi Bond is obtained in batch, and with this value (oWi) you can scale the mill industrial safety.

If you have the opportunity to work with grinding continues on a pilot scale study, test the open-circuit grinding also and compare. Carried with low ball filling (from 20 to 25% balls) and 50 to 55% solids. See your P80 and calculate oWi, you will have a big surprise.

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