Raw untreated green sand is very colloidal and has little or no water softening power. By heating the green sand to 400°C and subsequently treating it with a salt (NaCl) solution, a stable zeolitic sand is obtained which has good water softening power. This method is in actual use at the present time. It has been found that by modifying this treatment a zeolite with greater water softening power is obtained. The sand is first treated with a concentrated calcium chloride solution, and subsequently with a concentrated sodium chloride solution. The sand is then rapidly heated to a temperature of about 800°C and is then quenched in a salt solution.
Proceedings of the Iowa Academy of Science
©1924 Iowa Academy of Science, Inc.
Barthel, Eston L.
"The Preparation of Zeolytic Water Softening Materials,"
Proceedings of the Iowa Academy of Science, 31(1), 275-276.
Available at: https://scholarworks.uni.edu/pias/vol31/iss1/53