The bulk crystallization of alpha-lactose monohydrate from aqueous solution

Area of Science:

• Chemical Engineering
• Crystallization Science
• Materials Science

Background:

• Bulk crystallization of alpha-lactose monohydrate is crucial for various industries.
• Understanding nucleation and growth kinetics is essential for process optimization.
• Previous studies noted alpha-lactose's influence on crystal growth.

Purpose of the Study:

• To investigate the primary nucleation and crystallization kinetics of alpha-lactose monohydrate.
• To determine the impact of supersaturation, temperature, and pH on crystallization.
• To elucidate the reasons for unusually long induction times and growth behaviors.

Main Methods:

• Controlled experiments on bulk crystallization of alpha-lactose monohydrate from aqueous solution.
• Studied primary nucleation under varying supersaturation, temperature, and pH.
• Monitored induction times, nucleation extent, and crystal growth over extended periods.

Main Results:

• Observed extremely long induction times for nucleation, even at high supersaturations.
• Vigorous stirring was necessary to induce limited nucleation.
• Crystal growth exhibited periods of cessation and slow rates, with particle size stabilizing before yield maximization.

Conclusions:

• The anomer alpha-lactose, formed by mutarotation in solution, is proposed to inhibit nucleation.
• This anomer also influences crystal growth, leading to the observed extreme crystallization properties.
• Further research into alpha-lactose mutarotation is warranted to understand its crystallization impact.