An insight into interparticle forces and filterability of potassium sulphate crystals precipitated with ethanol and acetone
Advancing the chemical engineering fundamentals
Crystallization (T2-9P)
Keywords: precipitation, potassium sulphate, zeta potential, aggregation, filterability
Solvent effects on formation of secondary crystals, in semibatch operating precipitation, were studied with potassium sulphate using acetone and ethanol as an anti-solvent. Zeta potential measurements were carried out to investigate the attractive or repulsive interaction of primary crystals forming firstly via primary nucleation and crystal growth by varying the pH of the solution. To characterize the end product, the filterability of obtained crystals was determined using a Nutsche pressure filter. The obtained results showed that acetone yielded smaller crystal sizes and lower filterability than ethanol with the used precipitant feed rates. The isoelectric point for the acetone solution was obtained at a pH range of 5.5 to 6.5, whereas for the ethanol solution the isoelectric point was expected to be around a pH lower than 3.5 based on extrapolation. The zeta potential values varied less as a function of pH in acetone solutions than in ethanol solutions.
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Presented Wednesday 19, 13:30 to 15:00, in session Crystallization (T2-9P).
