A major problem in evaporative desalination processes has been the formation of thermally insulating mineral scales on the heat transfer surfaces. The scales reduce the heat transfer efficiency and increase the cost of production of potable water1 . Although successful methods have been devised for the control of "low temperature" scales such as calcium carbonate and magnesium hydroxide, the development of economical and reliable methods for eliminating persistent, pH insensitive, calcium sulfate nucleation and crystal growth is a more difficult problem1 . Besides its importance in the field of desalination technology, calcium sulfate formation is also of considerable interest to the geochemist2  and petroleum engineer3 . In attempts to control the extent of scale formation there are two general approaches; (a) modification of the crystal morphology so that the solids resist packing together as hard destructive scale but rather remain as a sludge which can be swept away by the liquid phase contacting the surface. (b) The addition of substances which will act as crystallization inhibitors to slow down or prevent the nucleation and subsequent growth of scale deposits.

Subject
Precipitation (solids), Phosphonates, Solids, Nucleation, Solubility, Calcium, Corrosion reactions, Constants, Ion concentrations, Solutions, Crystal growth, Calcium sulfate, Corrosion inhibitors
© 1976 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1976
Association for Materials Protection and Performance (AMPP)
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