A PROCESS FOR PREPARING HIGH PURITY AND LARGE SIZE CRYSTALS, BY ELIMINATING FINE CRYSTALS IN CRYSTAL SLURRY IN CRYSTALLIZER

摘要

This invention provides a process for preparing high purity and large size crystals by eliminating fine crystals in crystal slurry in a crystallizer, characterized in: mounting two filters (4, 6) in the crystallizer (5); discharging part of crystal slurry containing fine crystal less than certain size from the crystallizer (5), by passing it through one filter (4 or 6) mounted in the crystallizer (5); introducing said crystal slurry into a fine crystal eliminater (1); passing said crystal slurry in which fine crystals have been eliminated through another filter (6 or 4) mounted in the crystallizer (5) and returning to the crystallizer (5) by a recycle pump (2); using periodically the two filters and washing alternatively the two filters. This invention also provides a process for preparing high purity and large size bisphenol A-phenol adduct crystals and bisphenol A crystals.