The regeneration ability of silica gel
🕙 2023-08-25 👆
First, the regeneration of silicone after water absorption
After the silica gel adsorbs water, the water can be removed by thermal desorption. There are many ways of heating, such as electric furnace, flue waste heat heating and hot air drying. It is appropriate to control the temperature of desorption heating at 120-180 ° C, and it is appropriate to control the temperature of blue rubber indicator, discolored silica gel and blue silica gel at 100-120 ° C. The maximum temperature of various industrial silica gel regeneration should not exceed the following limits:
Coarse silica gel shall not be higher than 600℃;
Fine silica gel shall not be higher than 200℃;
Blue glue indicator (or discolored silica gel) shall not be higher than 120℃;
Silicone aluminum adhesive shall not be higher than 350℃.
After regeneration of silica gel, its moisture is generally controlled below 2% can be put back into use.
Second, the regeneration of silica gel after adsorption of organic impurities
⒈ roasting method
For coarse silica gel, it can be gradually heated to 500-600 ℃ in the baking furnace, about 6-8 hours to
The colloidal granules are white or yellowish brown. For fine porous silica gel, the roasting temperature should not exceed 200℃.
⒉ Rinsing method
The silica gel is absorbed in saturated water vapor to reach saturation after soaking in hot water and rinsing, and can be combined with detergent to remove waste oil or other organic impurities, and then dried and dehydrated after washing with clean water.
Solvent flushing method
According to the type of organic matter adsorbed by silica gel, the appropriate solvent is selected to dissolve the organic matter adsorbed in the silica gel, and then the silica gel is heated to remove the solvent.
Third, silicone regeneration should pay attention to the problem
When drying and regeneration, attention should be paid to gradually increase the temperature, so as not to cause severe drying to crack the colloidal particles and reduce the recovery rate.
⒉ When roasting and reproducing silica gel, too high temperature will cause the change of silica gel pore structure and significantly reduce its adsorption effect and affect the use value. For blue rubber indicator or color-changing silica gel, the temperature of desorption regeneration should not exceed 120 ° C, otherwise it will lose the color effect due to the gradual oxidation of the color developer.
The silica gel after regeneration should generally be sieved to remove fine particles to make the particles uniform.
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