“Filter Aids” is a group of inert materials that can be used in filtration pretreatment...
“Filter Aids” is a group of inert materials that can be used in filtration pretreatment. There are two objectives related to the addition of filter aids. One is to form a layer of second medium which protects the basic medium of the system. This is commonly referred to as “precoat”. The second objective of filter aids is to improve the flow rate by decreasing cake compressibility and increasing cake permeability. This type of usage is termed as “admix” or "body feed". Filtration without filter aid, with precoat, and with precoat and body feed is shown in Fig. 1 (Eagle-Pitcher Minerals, Inc., 1970).