• Case Studies

Control of continuous crystallization


Chemical recovery in the pulp mill is based on leaching and recrystallization. Disturbances in the leaching stage induce variations in crystal size distribution. This creates problems in the centrifuges resulting in capacity problems or even breaks in the operation.


A Pixact Crystallization Monitoring (PCM) system is used to measure crystal size and the fraction of fines in the suspension.


The PCM system provides the means to react quickly to any changes in crystal population. In addition, observations based on the PCM data led to several improvements in the process operation.

Process parameters

Crystalline product    Na2SO4, Na2CO3
Size distribution  20…1000µm
Solids concentration    45 w-%
Temperature         90°C
Pressure    4 Bar
Other remarks   pH 10-11


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