Silica is the general name for white powdery X-ray amorphous silicic acid and silicate products, mainly referring to precipitated silica, fumed silica and ultrafine silica gel, also including powdered synthetic silicic acid Aluminum and calcium silicate, etc. White carbon black is a porous material, and its composition can be expressed as SiO2·nH2O, where nH2O exists in the form of surface hydroxyl groups. Soluble in caustic alkali and hydrofluoric acid, but insoluble in water, solvents and acids (except hydrofluoric acid). It is high temperature resistant, non-flammable, tasteless, odorless, and has good electrical insulation.
Chinese name: white carbon black
English name: Silica
CAS number: 10279-57-9
EINECS number: 238-878-4
physical properties
Appearance: white powder or granular or irregular lumps.
True density: about 2.0g/mL
False density: about 0.2g/mL
High temperature resistance, non-flammable and good electrical insulation.
chemical properties
Can react with caustic soda: SiO2·nH2O+2NaOH=Na2SiO3+(n+1)H2O
Can react with hydrofluoric acid: SiO2·nH2O+4HF=SiF4+(n+2)H2O
Main chemical indicators
SiO2 content (dry product) ≥90%
Sieve residue (45μm) ≤0.5%
Heating loss: 4.0-8.0%
Loss on ignition: (dry product) ≤7.0%
pH value: 5.0-8.0
Total copper content: ≤30mg/kg
Total manganese content: ≤50mg/kg
Total iron content: ≤1000mg/kg
DBP absorption value: 2.00-3.50cm/g
Specific surface area: different ranges for different uses, generally 145-165m2/g (HT2) 165-185m2/g (HT1)
200-300m/g（HT3）
Main physical properties (with rubber products)
Tensile strength ≥17.0Mpa
Tensile strength ≥6.3Mpa
Elongation at break≥675%