Compaction of filter cakes and its consequences on filter cake structure and dewatering properties

摘要

Investigations with several fine-grained mineral slurries were carried out to obtain information on how their compaction behaviour is influenced by the compression pressure applied. For this reason, filter cakes were compressed within a pressure range of1 and 2500 bar. By means of different methods, the micro- and macroscopic structures of the filter cakes were then analysed. From the results, clear conclusions could be drawn with respect to the characteristic compaction mechanisms of mineral slurries.Three mechanisms (particle approach/-orientation, destruction of particle bridges, limit of particle stability) were found to be effective. These mechanisms appear in the aforementioned order and exist in clearly defined, product-specific pressure ranges. Furthermore, for the investigated slurries, correlations between filter cake structure and a number of selected filter cake properties are presented by way of example. The experimental results indicate that the changes in consolidation mechanism can befound for all filter cake properties by analogy, but the observed changes in the compression pressure dependence are generally more distinct. The aforementioned findings can help reduce the number of experiments required.