Influence of pre-dewatering on the success of cake washing

ABSTRACT

Cake washing is one key challenge after filtration. It is used to improve the product quality of filter cakes. Many studies deal with washing of saturated filter cakes and are used as the basis for cake washing models. However, to avoid mixing of supernatants (e.g. suspension liquid and wash liquid) on the cake surface during production processes, the cake is pre-dewatered and thus the pores are undersaturated. This paper demonstrates the influence of different start saturations (different pre-dewatering times) on the displacement regime of a washing curve compared to washing saturated filter cakes. An increase in saturation (filling) also takes place at the beginning of the washing of undersaturated filter cakes. A new filling regime located at the beginning of the washing process is clearly defined before the known displacement regime. The extent of the filling regime depends mainly on the initial saturation before washing process.

KEYWORDS:

• Cake washing
• equilibrium saturation of rewetting
• filling regime
• pre-dewatering
• washing undersaturated filter cakes

Nomenclature

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Acknowledgements

Parts of the presented results have been supported by AiF (IGF 19169 N). Further thanks go to the PhD students from the Institute of Mechanical Process Engineering and Mineral Processing, TU Bergakademie Freiberg.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Bundesministerium für Wirtschaft und Energie [IGF-Nr. 20687 N].