A Systems Engineering Approach to Dry-Milling with Grinding Aid Additives

Executive Summary

Type and dosage of grinding aid.

Mill geometry and design;

Process parameters;

Product transport behavior;

Product breakage characteristics;

consumption in relation to:

dynamical population balance model predicting product size distribution and energy

Moreover, the continuous grinding process modelling approach is being structured as a

stressing and transport independently.

grinding. The results also confirm the necessity of describing the phenomena of powder

behavior, although beneficial for continuous processing, does not guarantee an effective

but with good results for milling efficiency for both materials. It is clear that improved flow

flowability for both materials. The glycol presented negligible effect on powder flowability,

In terms of flowability measurements, the carboxylic acid promoted notable increase in

additive.

similar effects compared to each other, but improving efficiency in comparison to no

similar to grinding without additive. For the calcium carbonate the additives presented

Alcohol and glycol were quite effective, while the use of carboxylic acid resulted in results

alumina, the grinding aids show different efficiency in reducing energy consumption:

and powder flowability measurements of the product were conducted. In the case of

After defining materials and establishing experimental methods, first batch grinding tests

or continuously operated ball mill as well as an reflector-wheel air classifier are selected.

acid and a Glycol. For the experiments, a 4 liter batch ball mill and a 47 liter, batch-wise

studied. Three substance classes were adopted as grinding aids: An Alcohol, a Carboxylic

In this project, dry grinding of the materials alpha alumina and calcium carbonate is

Amount of material coated on equipment surfaces.

Total mass of product inside the mill and residence time

Powder flowability;

Tendency of fine particle agglomeration;

Product fineness after grinding;

aids impact powder material mainly in:

consumption and/or to reach a certain product fineness. During milling operations, grinding

to the process in order to increase the product throughput, decrease the specific energy

by grinding aids. Grinding aids are defined here as liquid or dry substances that are added

manipulation of the material properties and, thus, the grinding and classification efficiency

optimizing and scaling industrial dry grinding processes, with a special focus on the

This project aims in developing a system engineering approach for understanding,