Types

Silica gel can be categorized according
- shape
- size
- pore structure or
- chemical composition

Silica gel shapes
- granular: Silcarbon SGG
- beads: Silcarbon SGR

Silica gel size

Silica gel can be produced in various sizes from powder to coarse beads or granular chunks.

Standard sizes are 1 – 3 mm, 2- 5 mm, 3 – 6 mm, 4 – 8 mm and 5 – 11 mm

Silica gel pore structures
- fine porous A-type with average pore size of approx. 25 nm
- large porous B-type with average pore size of approx. 65 nm
Due to the different pore structure the water adsorption characteristics of both types vary accordingly as described in diagram below.

Silica gel composition

Standard silica gel is decomposed upon contact with water droplets. By adding aluminium into the silicate structure a silica gel is produced that is water resistant. The more aluminium is added the better the water resistance; on the other hand the water adsorption capacity is reduced by the aluminium content.

The water resistant silica gel is therefore used in applications where water droplets occur or can occur. It is applied as a first-contact layer in adsorber units in order to protect the high adsorptive fine-pored silica gel that is put behind the water resistant material, so the highest possible removal of humidity is achieved.