Abstract
The filtration mechanism for a precoat type filter using powdered ion exchange resin as filter aid was investigated with a small experimental filter.
Where iron oxide particles, α-Fe2O3, are used as suspended solids, the charge of resin flock consisting of anion exchange resin and cation exchange resin is neutralized when particles are captured by the precoat resin layer. So resin flock disperses and pore size of the resin layer becomes small with time.
It was found that the mechanism of capturing particles is depth filtration and, in addition, cake filtration that begins to occur locally and spreads over all the filter area gradually.
In addition, an experimental expression of the pressure differential of the filter in depth filtration and cake filtration was obtained and was usable to evaluate the pressure differential rise caused by captured particles.
