silica gelSspecifications

What is silica gel?

Glassy hard silica granules 99.5% purity (SiO2)

Silica gel is an amorphous form of silicon dioxide, which is synthetically produced in the form of hard granules having the appearance of crystals. A microporous structure of interlocking cavities gives a very high surface area (800 square meters per gram). It is this structure that makes silica gel a high capacity desiccant. Water molecules adhere to the gels surface because it exhibits a lower vapour pressure than the surrounding air. When an equilibrium of equal pressure is reached, no more adsorption occurs. Thus the higher the humidity of the surrounding air, the greater the amount of water that is adsorbed before equilibrium is reached. The beauty of silica gel is the physical adsorption of water vapour into its internal  pores. There is no chemical reaction, no by products or side effects. Even when saturated with water vapour, silica gel still has the appearance of a dry product, its shape unchanged.

Silica gel has many other properties that makes it extremely effective as a desiccant.

• It will adsorb up to one third of its own weight in water vapour. This adsorption efficiency is approximately  35% greater that typical desiccant clays, making silica gel the preferred choice where weight or efficiency are important factors.

• It has an almost indefinite shelf life if stored in airtight conditions.

• It can be regenerated and reused if required. Gently heating silica gel will drive off the adsorbed moisture and leave it ready for reuse.

• It is a very inert material, it will not normally attack or corrode other materials and with the exception of strong alkalis and hydrofluoric acid is itself resistant to attack.

• It is non-toxic and non-flammable.

• It is most frequently and conveniently used packed in a breathable sachet or bag. These are available in a wide range of sizes suitable for use with a wide range of applications.

Prevents moisture damage to electrical goods and electronic components (internally and externally), scientific and optical instruments, communication equipment, metallic parts, leather goods, tools and many other small to medium sized items in use, stored or in transit.

Specification.

White Silica Gel

Material Description : Glass, har, irrgualr shaped granules with a very high purity of approx. 99.5% SiO2 (Dry basis) and an internal surface area of approx. 800 m2 ­­­­­­­/g. Because of its very large surface area Silica gel exhibits a high adsorption for water vapour. Silica gel can be reactivated without significantly impairing the efficiency. It is therefore very economical, easy to dispose of and without any known adverse effects on the evironment. Supplied as desiccant absorbent, silica gel conforms to US MIL-D3716, BS-2540, DIN 55473.

Formula : SiO2.n(H2O) – amorphous form of silica

CAS-Nr. : 7631-86-9

Physical : Typical water vapour adsorption capacity at 25 0C

Characteristics :     at 20% relative humidity >= 10.7%
                                     at 40% relative humidity >= 22.3%
                                     at 80% relative humidity >= 32.5%
                                   
                                    Loss on ignition (1200C) (on dry basis)   max. 3%
                                    Bulk density                                          >= 780
                                    PH value                                                     4-7
                                    Specific resistance                               >= 3,000

Standard grain size :
1.0 – 2.0 mm, 1.0 – 3.0 mm, 2.0 – 4.0 mm, 4.0 – 8.0 mm. Other special gradings on request.

Applications :
Due to its extremely high adsorptive capacity Silica gel has a multitude of uses; Static adsorption (=removal of moisture and control of humidity in packing and other enclosed spaces without induced air flow). Dynamic adsorption (=removal of water from a continuously flowing gas or liquid stream). The temperature at reactivation should not exceed 200 0C

Packaging :
Packaged from 0.5 gram up to 500 grams by paper or nonwoven; airtight in PE barriers and carton.

Handing :
Silica gel desiccant must always be kept in airtight containers to avoid pre-adsorption with water vapour. Face masks should be used at continual exposure to extensive dusting.

Blue Silica gel

Material Description : Glassy, hard, irrgualr shaped granules with a very purity of approx. 99% SiO2 (Dry basis) and sn internal surface area of approx. 800 m2/g. Because of its very large surface area Silica gel exhibits a high adsorption for water vapour. Blue (indicating) silica gel contains 0.3 – 0.4 % of Cobalt (as Co). The blue granules change color to pink when saturated and exhausted. The change of color is reversible. The material changes color back to blue when being reactivated. Blue (indicating) silica gel conforms to US MIL-D-3716A, Type IV, Grade H; BS3523.

Formula : SiO2 . n(H2O) – amorphous form of silica

CAS-Nr. :             7631-86-9 (Silica)
                            7646-79-9 (CoCl2)

Physical  Characteristics : Typical water vapour adsorption capacity at 25 0C
                        At 20% relative humidity             >= 10.0%
                        At 40% relative humidity             >= 20.8%
                        At 80% relative humidity             >= 31.2%

                        Loss on ignition (120 0C) (on dry basis)   Max. 3%
                        Bulk density                                >= 780
                        PH value                                           6-7
                        Speciffic resistance                      >= 1,500

Standard grain size :
1.0 – 2.0 mm, 1.0 – 3.0 mm, 2.0 – 4.0 mm, 4.0 – 8.0 mm, other special gradings onrequest.

Applications :
Blue (indicating) Silica gel is a desiccant intended for the removal of moisture from air, other gases, and liquids by static and dynamic means. The material is impregneted with an indicator (Cobalt) and should be used whenever a visual indication of degree of saturation of the desiccant is required.The temperature at reactivation should not exceed 100 0C

Packing :
Packaged from 0.5 gram up to 500 grams by paper or nonwoven; airtight in PE barriers and carton.

Handing :
Silica gel desiccant must be kept in airtight containers to avoid pre-adsorption with water vapour. Face masks should be used at continual exposure to extensive dusting.

note:
Silica gel is actually pretty much non-toxic, though you should probably drink
a lot of water if accidentally eaten, note that we say "DO NOT EAT" on it's packaging rather than WE ADVISE YOU NOT TO EAT IT, there's no statement about whether or not to induce vomiting.