PROCESS FOR SEED CRYSTAL PREPARATION FOR PHOSPHORIC ACID CRYSTALLIZATION

摘要

The present invention relates to the processing of phosphoric acid by crystallization starting with phosphoric acid and adding relatively large amounts of fine, relatively pure seed crystals to acid which has been cooled to supersaturated conditions. Crystallization thereafter proceeds under conditions which substantially favor growth on the seeds which are added and disfavor secondary nucleation. The present invention particularly describes a seed crystal generator for use in the foregoing process in which relatively high purity phosphoric acid, containing 60% to 66% P2O5 is cooled to a temperature of at least 5 DEG to 10 DEG C. below zero and thereafter nucleated under agitation for less than ten minutes in a small crystallizing vessel.