Evaluation of enhanced liberation by comminution under high pressure

A systematic evaluation has been undertaken of the degree of liberation obtained when a sample of lead-zinc ore was comminuted under high pressure. The precision of evaluation by simple point-counting and similar techniques was examined. The liberation achieved by high-pressure comminution under different conditions was compared with that achieved by conventional grinding with a laboratory vibratory rod-mill. An estimate of the liberation achieved at similar sizes under the two sets of conditions reveals statistically higher degrees of liberation for high-pressure comminution. There is also evidence to suggest that comminution in a wet environment enhances the degree of liberation at similar sizes by comparison with other methods tested. Support is provided for earlier tests that showed improvements in the flotation performance of similar-size material generated by high-pressure comminution.