SCIENTIFIC BASES FOR PREPARATICN OF DIATOMITE AND PERLITE FLTER-AID

According to the filtration mechanism andfiltration formula, it is considered that thesurface area, bulk density and grain size distri-bution of filter-aid are the main factors affectingthe filtration rate. On the basis of analysing phy-sical and chemical properties of diatomite and per-lite, the scientific bases for preparation of filteraid are discussed. It is possible that the complexfilter aid, which is made up of low grade diatomiteand perlite, is favourable to build-up a fine"steely-bridged structure" for the filter cake, andits filtration performance of beer could be improvedas good as that of commercial filter-aid made fromhigh grade diatomite. The above points have beendemonstrated by the results of laboratorial andindustrial experiments of beer filtration.