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UPGRADING THE PERFORMANCE OF THE HYDRATE DISC FILTERS AT NABALCO

Lawson, C., Grimmond, D. and Kern, R.

Filtration of Aluminium Hydroxide slurries is an important part of the Bayer Process as implemented at the Nabalco Alumina Plant at Gove, Australia.

During the plant expansion to 1.6 million tonnes per year in 1991 it was necessary to upgrade the capacity of the filtration equipment. "Bokela" filtration consultants from Karlsruhe, West Germany were selected to propose modifications to the existing vacuum disc filters in order to achieve the required increase in capacity.

Laboratory and plant trials were conducted to define the necessary design modifications.

This filter upgrade, together with an upgrade of the control room software, now allows a far superior performance of the disc filters. Operating parameters have been optimised to produce a filter cake low in moisture whilst maintaining the required throughput.

This paper describes the upgrade of the vacuum disc filters in the hydrate filtration area with particular attention to the design modifications and the associated improvements in performance.