Patent ID: 7056356

Claim:
A process for crystallizing substances from solutions or dispersions containing these substances, in an apparatus having an inner and an outer circulation system, i) the inner circulation system being present in a crystallizer containing a classifying zone and said crystallizer containing a dispersion which comprises crystals of the substances and is moved through the inner circulation system, ii) a part-stream of the dispersion being transported from the crystallizer via the classifying zone into the outer circulation system, iii) crystals contained in this dispersion being partially dissolved in the outer circulation system by a heat exchanger, iv) the dispersion or the solution formed by complete dissolution of crystals from the dispersion being subsequently recycled to the inner circulation system of the crystallizer, v) a solution and/or dispersion containing the substances being fed to the crystallizer and/or the outer circulation system and vi) a dispersion comprising crystals of the substances being removed from the outer circulation system and/or from the crystallizer, vii) wherein a part-stream of the dispersion comprising crystals is removed from the inner circulation system and this part-stream is fed via a line for recycling the dispersion to the outer circulation system where the line enters the outer circulation system before the heat exchanger to overstretch the dissolution capacity of the heat exchanger by feeding in this part-stream without the crystals of the dispersion being dissolved to a substantial extent.