THE LIME slaker at Racecourse mill was a horizontal rotating drum with an
inclined grit removal system typical of the slakers in the Australian sugar
industry. With the addition of a sugar refinery to the site the lime slaker needed
to be operational throughout the year but it was becoming unreliable in operation
and required constant supervision to produce milk of lime consistently. During
the 1998 crushing season, laboratory lime slaking tests were conducted at
different initial slaking water temperatures and these data were used to develop a
control system for a new batch slaking system. The new batch slaking system
was designed with a vertical tank slaker on load cells. Water and lime addition
are both measured using the load cells and temperature probes record the water
and slaking temperatures. The fully automatic system was installed in April
1999. This paper incorporates the initial laboratory slaking tests, lime slaker
design and operation experiences with the new system.