Silica gel is a highly active inorganic adsorbent material is transparent or white granular solid . Has an open porous structure , strong adsorption , can absorb a variety of substances. Such as moisture absorption , moisture absorption capacity of approximately 40%.
Blue Silicone - such as adding cobalt chloride, cobalt blue when dry , red after absorbing water . Blue Silicone because it contains a small amount of cobalt chloride , toxic, and food should be avoided contact and inhalation of the mouth , such as the occurrence of poisoning should immediately seek medical treatment.
Silica gel in the course of the medium due to the adsorption of water vapor or other organic substances , the adsorption capacity decreased, can be reused after regeneration .
Silica gel regeneration after adsorption of water vapor
Silica gel after moisture absorption, heat by stripping way to remove moisture, there are many types of heating way, such as electric heating furnace, flue waste heat heating and hot air drying, etc.
Stripping heating temperature control in the 120-180 ℃ advisable, for the blue gel indicator, allochroic silica gel, DL blue silica gel is controlled in 100-120 ℃ advisable. All kinds of industrial silica gel regeneration when the highest temperature should not be more than the following limits:
Coarse silica gel is not higher than 600 ℃;
Of fine silica shall not be higher than 200 ℃;
Blue glue index agent (or color silica gel) shall not be higher than 120 ℃;
Silicon aluminum adhesive shall not be higher than 350 ℃.
After the regeneration of silica gel, its general control moisture below 2% can be put into use again.
Silica gel adsorption of organic impurities regeneration
For coarse -pored silica gel , can be placed inside the roaster gradually heated to 500 - 600 ℃, after about 6-8 hours to micelles can be white or brown . On pore silica gel, calcination temperature should not exceed 200 ℃.
⒉ rinsing method
Silica gel adsorption of the saturated water vapor saturated with heat water for rinsing , can be combined with a detergent to remove oils or other organic impurities, and then washed with water after drying dehydration.
⒊ solvent flushing method
According to silica gel adsorption organic species , the choice of an appropriate solvent adsorbed on silica dissolution of organic matter inside , and then heated to remove the solvent silicone .
Silicone regeneration should pay attention to the problems
⒈ drying regeneration should pay attention to grasp the gradual increase in temperature caused by dry particles in order to avoid violent burst , lower recovery rates.
⒉ on silicone baking regeneration, the temperature is too high will cause changes in the pore structure of silica gel significantly reduced the adsorption effect, affecting the value in use . For blue gel indicator or silica gel , desorption regeneration temperature should not exceed 120 ℃, otherwise they will be gradually oxidized color developing agent and lose color effects .
⒊ regenerated after silica fine particles should generally be removed by sieving , to allow uniform particles .
Storage and Packaging
Silicone has a strong capacity to absorb moisture and should therefore be stored in a dry place , between the ground and the packaging have shelves . Packaging with drums , drum , cardboard boxes, plastic bottles, polyethylene plastic bags, flexible container bags and so on. Transport process should avoid rain, moisture and sunlight .
25 décembre 2014