Environmental Soils and Biogeochemistry Laboratory
- Desiccant Chart Comparisons. Sorbant Systems Inc. Online at http://www.sorbentsystems.com/desiccants_charts.html [Last accessed March 20, 2014].
TECHNICAL DATA – REGENERATION OF DRIERITE DESICCANTS
After normal use, any of the forms of DRIERITE may be regenerated for reuse. The operation is simple and involves only standard equipment. The used and exhausted desiccant should be ventilated to remove vapors, if any, and stored in a convenient container until a sufficient amount is accumulated to justify the work of regeneration.
Regular and Indicating DRIERITE
For the regeneration of Indicating DRIERITE and small lots of Regular DRIERITE , the granules may be spread in layers one granule deep and heated for 1 hour at 210° C or 425° F. The regenerated material should be placed in the the original glass or metal container and sealed while hot. The color of the Indicating DRIERITE may become less distinct on successive regenerations due to the migration of the indicator into the interior of the granule and sublimation of the indicator.
Commercial Grade and Du-Cal DRIERITE
Exhausted Commercial DRIERITE or Du-Cal DRIERITE should be spread about 1 inch deep in shallow pans and heated in a oven at 450° F or 230° C for 2 hours to achieve complete dehydration. The regenerated material should be placed in the original container and sealed while hot.
The Importance of Temperature
The temperature at which DRIERITE desiccants are regenerated is crucial in restoring DRIERITE to its original condition. Absorbed moisture is water of hydration and is chemically bound to the calcium sulfate of DRIERITE. Temperatures in the range of 400° – 450° F are required to break these bonds and release absorbed moisture. Lower temperatures, regardless of heating time, will not regenerate DRIERITE unless applied under vacuum (26″ Hg, 325° F or 28″ Hg, 275° F). Care should be taken not to overheat DRIERITE Desiccants. High temperatures can alter the crystal structure and render the desiccants permanently inactive.