So Frequently when the term desiccant is used, people automatically think about the 3 chief types of desiccants: Indicating Silica Gel, Molecular Sieve, and Clay desiccant. Those who have heard of other desiccants, like Calcium Oxide, Montmorillonite Clay and Calcium Sulphide, may or may not have a thorough comprehension of these desiccant types. Recognizing how important proper discernment is where the use of desiccants is concerned, IMPAK has generated the next reference to be utilised along with the data on the webpage in the Quick Links navigation menu on the left for correctly evaluating application needs and deciding on the proper desiccant for those programs. For a more comprehensive comparison, please refer to our Chart Comparisons page.
Montmorillonite Clay, Silica Gel, Indicating Silica Gel, Molecular Sieve, Calcium Oxide, Calcium Sulphate, Additional Adsorbents. Montmorillonite Clay is a naturally occurring adsorbent generated by the controlled drying of magnesium aluminum silicate of this sub-bentonite type. This clay will regenerate for repeated use at very low temperatures without significant deterioration or swelling. But this property causes clay to give up moisture easily back into the container as temperatures rise. Clay is a good Standard desiccant that operates satisfactorily below 120°F roughly 50°C. Above 120° F, there is a chance that the clay will give moisture up as opposed to pulling it in, so expected storage and transport conditions should be considered. The upside to clay is that it is normally the cheapest desiccant per pound.
Clay is highly Successful within normal temperature and relative humidity ranges. Its appearance is that of little Gray pellets. Care must be taken to make certain any low level impurities in the clay aren’t incompatible with the packed product. It is a naturally occurring mineral that is purified and processed to either granular or beaded form. As a pharmaceutical desiccant, it is a mean pore size of 24 angstroms and has a strong affinity for moisture molecules. The silica gel will pull in moisture at temperatures up to 220°F 105°C. As temperature goes above 100°F, the rate of moisture pickup will slow down but the silica gel will still work. Silica gel Performs best at room temperatures 70° to 90°F and higher humidity 60 to 90 percent RH and will drop the relative humidity at a container down to approximately 40 percent RH. In America, silica gel is often utilized in pharmaceutical and food applications as just silica gel has been approved by the FDA for direct contact with these products.