RELATING NUCLEATION AND THE METASTABLE ZONE WIDTHS IN SYSTEMS CONTAINING MIXTURES OF NA2CO3 AND NA_2SO_4

摘要

An experimental crystallizer was constructed from a Jerguson gauge that provided for circulation of liquid, visual observation of the system contents, and operation at pressures up to 1000 kPa and temperatures over the range from 100°C to 170°C. The metastable zone width for crystallization in the Na_2CO_3-Na_2SO_4-H_2O system was determined as a function of total solute concentration and the ratio of sodium carbonate to sodium sulfate. The polythermal method was used in the measurement, and supersaturation was generated by heating the system contents at a constant rate. Primary nucleation kinetics were related by the classical crystallization theory to system temperature and concentration, with the relationship developed it is possible to predict the metastable limit for given systems.