1 Jan 2008


Gerard van Houwelingen, Royal HaskoningDHV, Amersfoort, The Netherlands.

Peter Piekema, Waternet, The Netherlands


The Crystalactor® is an up-flow fluidized bed crystallization reactor. Zentner developed an up-flowfluidized bed reactor with a spiralling flow pattern for water softening in Tschechoslovakia in the 1930-s. Sand grains are used as seed material on which calcium carbonate crystallizes and forms sphericalpellets of around 1 mm diameter. This type of reactor is best known under the name Spiractor, atrademark that was filed by Permutit in 1943. This type of reactor applies a relatively crude way ofmixing milk of lime and water in the bottom zone of the reactor (...)

Keywords: Crystalactor®, calcium phosphate, magnesium phosphate, struvite, Spiractor, pellet reactor