Silica gel desiccant is a physical adsorption desiccant rather than a chemical reaction moisture absorbent desiccant, and silica gel is the only FDA-approved desiccant raw material that can directly contact food and pharmaceuticals. Compared to other desiccants, silica gel desiccants are safer for use in food moisture protection. So do you know if the silica gel desiccant can be regenerated? Today, let's take a look at whether this silica gel desiccant can be regenerated.
1. Regeneration after silica gel adsorbs water vapor: After silica gel adsorbs water, it can be removed by thermal desorption. There are various heating methods, such as electric furnace, flue heat and hot air drying. It is appropriate to control the temperature of de-addition heat at 120-180 ° C. For blue glue indicator, color-changing silica gel, and DL blue silica gel, it is appropriate to control 100-120 ° C. The maximum temperature during the regeneration of various industrial silica gels should not exceed the following limits: coarse-pored silica gels must not exceed 600 ° C; fine-pored silica gels must not exceed 200 ° C; blue gel indicator (or discolored silica gel) must not exceed 120 ° C; silicon aluminum The glue must not be higher than 350 ° C. After the silica gel is regenerated, its moisture content is generally controlled below 2% and it can be put back into use.
2. Matters needing attention when using silica gel again:
(1) When the firing regeneration silica, silica gel temperature will cause changes in pore structure and significantly reduce its adsorption effect, impact value. For blue gel indicator silica gel or discoloration, desorption regeneration temperature should not exceed 120 deg.] C, otherwise they will gradually lose color developing agent oxidized color-developing action.
(2) after the regeneration silica should generally be sieved to remove fine particles to keep the particles uniformly. Bi source Zhengzhou open silica gel in the course of the medium by the adsorption of water vapor or other organic substances, the adsorption capacity decreased, can be reused after regeneration by.