Plant for controlling critical fractions in mineral grinding - using autogenous, grinding, circuit with primary mill having fractioning equipment

摘要

Before reaching the primary mill, the mineral material is divided into rough and finer fractions, and the finer fractions are then further reduced to a state where they contain critical and subcritical fractions. They are then fed together with the rough fractions to the primary mill. To reduce the problem with critical material fractions, they are made to re-circulate (11) to the primary mill (1) over a flow or quantity measurer (12) for recording the factual re-circulating material amt. The recorded value is compared with a theoretical value for circulating amts. for control of a crusher (5) so that the circulation amt. is maintained at a level equal to that of the theoretical value.