IMPROVING THE PERFORMANCE OF THE RED MUD DRUM FILTERS AT EURALLUMINA WITH THE BOKELA REVAMPING PROGRAM
Langeloh, T., Bott, R., Hahn, J., Ventura, L., and Ferraro, L.
EURALLUMINA S.P.A. operates 6 drum filters of 100 m2 each for red mud filtration in the Alumina refinery at Portoscuso. Since these drum filters did no longer meet the increased requirements of EURALLUMINA with respect to throughput capacity, cake washing and cake moisture, BOKELA GmbH from Karlsruhe, Germany was selected to provide a de-bottlenecking solution with the BOKELA filter revamping program which comprises the following three phases
- Diagnostic step,
- Engineering step,
- Realisation step.
The program started with laboratory and plant trials that were performed by BOKELA and which revealed a potential of 40% increase of filter capacity by carrying out some modifications of the filter design. The test results and the proposed design modifications convinced EURALLUMINA to start with the upgrading of the first red mud drum filter. This filter revamping project was realised in a step by step co-operation of BOKELA and EURALLUMINA according to the following schedule:
- Modification report by BOKELA with proposal of modifications in the drum filter design
- Decision of EURALLUMINA on the design modifications to be realised
- Manufacturing drawings by BOKELA
- Machining and fabrication by EURALLUMINA
- Installation by EURALLUMINA supervised by BOKELA
- Commissioning supervised by BOKELA
The main upgrading measures that were carried out this way are:
- Improvement of the cake discharge
- Modifications to the control valve
- Improved cake washing
- Modification to the filter drive
Thus, the foreseen increase of the throughput capacity could be achieved while the cake washing was also improved. This success motivated EURALLUMINA to proceed with the de-bottlenecking of the other 5 red mud drum filters.