Close circuiting autogenous and semi-autogenous mills is an
energy efficient way of grinding and a number of operations have
utilised this in the design of their comminution circuits. Owing to
the large flow of slurry through the mill that results from
operating this way the grates and pulp lifters have to be designed
to cope. However, the literature has little or no information on
how grate and pulp lifter size and design are related to their
ability to remove slurry from the mill. Over the last few years the
JKMRC has been researching this area and has developed
relationships between grate/pulp lifter design and flowrate
capacity. At the same time it has determined the major causes of
pulp lifter inefficiency and a solution to preventing this
inefficiency (the Twin Chamber Pulp Lifter). This paper
describes the models that have been developed through this
program and uses industrial scale data to illustrate their accuracy.
Results from the industrial trials of the Twin Chamber Pulp
Lifter are also presented.