Improved C-control of crystallization with reduced calibration effort via conductometry

• Development of supersaturation control (C-control) with reduced calibration effort.
• Effects of seed size, seed loading and level of supersaturation on two model systems.
• Washed seed crystals do not always lead to a more uniform product CSD.
• Importance of quantitative assessment of CSD reproducibility from repeat experiments.

Supersaturation control (also termed concentration control or C-control) is increasingly being applied to obtain desired particle characteristics in crystallization processes. Here, a methodology for improved multivariate modelling in supersaturation control with reduced calibration effort is developed. The technique is implemented experimentally for C-control of potash alum–water and ammonium oxalate–water systems using conductivity measurements in the solution phase. The effects of seed size, seed loading and level of supersaturation on product quality are investigated and discussed.