ΣΧΗΜΑΤΙΣΜΟΣ ΘΕΙΙΚΟΥ ΑΣΒΕΣΤΙΟΥ ΣΕ ΥΔΑΤΙΚΑ ΔΙΑΛΥΜΑΤΑ

IN THIS THESIS, WE STUDY THE PRECIPITATION OF CALCIUM SULFATE FROM AQUEOUS SOLUTIONS AT SUPERSATURATIONS SUFFICIENT FOR SPONTANEOUS PRECIPITATION AND IN THE TEMPERATURE RANGE BETWEEN 20 -80 C. AT THESE CONDITIONS, THE ONLY PHASE FORMING WAS CALCIUM SULFATE DIHYDRATE. THE INDUCTION PERIODS AND THE SUBSEQUENT RATES OF PRECIPITATION WERE FOUND TO STRONGLY DEPEND ON THE SOLUTION SUPERSATURATION AND TEMPERATURE. DECREASE OF SUPERSATURATION RESULTED IN CHANGE OF THE CRYSTAL GROWTH-MECHANISM FROM SURFACE NUCLEATION TO A STEP DISLOCATION MECHANISM. THE PRESENCE OF ORGANOPHOSPHORUS COMPOUNDS HEDP, ENTMP AND NTMP) EVEN AT VERY LOW CONCENTRATIONS (A FEW PPM) DECREASED THE RATES OF CALCIUM SULFATE DIHYDRATE PRECIPITATION IN THE ORDER (ENTMP>NTMP>>HEDP) AT CONDITIONS OF SUSTAINED SUPERSATURATION. MOREOVER, WE HAVE STUDIED THE INFLUENCE OF DIVALENT METAL-IONS (CD, MG, ZNAND SR) AT SUSTAINED SUPERSATURATION. THE EFFECT OF THESE METAL-IONS WAS LIMITED IN THE DECREASE OF SOLUTION SUPERSATURATION. FINALLY, THE PRESENCE OF CRYSTALS OF CALCIUM SULFATE DIHYDRATE FAVOURED THE FORMATION OF CALCIUM CARBONATE POLYMORPHS AT HIGH TEMPERATURES.

Grantor dc:publisher

University of Patras

Year dc:date

1991

Authors dc:creator

• Klepetsanis, Pavlos
• Κλεπετσάνης, Παύλος

• Αναστολή
• Θειϊκό ασβέστιο
• ΚΑΘΑΛΑΤΩΣΗ
• Καταβύθιση
• Κρυστάλλωση
• CALSIUM SULFATE
• Crystal growth
• Inhibition
• Precipitation
• Scale
• Επιστήμες Μηχανικού και Τεχνολογία
• Επιστήμη Χημικού Μηχανικού
• Engineering and Technology
• Chemical Engineering

Language dc:language

gre

Identifier

10.12681/eadd/1758

OAI identifier oai:identifier

oai:10442/1758