A list,
Silica is the main component of silica, because it is white, and the main physical properties and uses of carbon black is similar to the name.
White carbon black can be divided by different production methods of precipitated silica, precipitated hydrated silica) the gas phase method of white carbon black (gas phase silicon dioxide), two kinds of production methods, properties and USES also have very big distinction, introduce the following the product is produced with sulfate precipitation, namely, of precipitated silica white carbon black are all involved in the precipitation under white carbon black.
Name definition and molecular formula
The scientific name of silica is precipitated hydrated silica.
Definition: Precipitated hydrated silica is a material composed of amorphous particles obtained by precipitation from a soluble silicate aqueous solution.
Chemical formula: SiO2•nH2O
Three, the main nature
1. Physical properties
Appearance: white powder or granular or irregular block.
True density: about 2.0g/ mL False density: about 0.2g/ mL (common product).
High temperature resistance, non-combustion; Electrical insulation is good.
2. Chemical properties:
Can react with caustic soda SiO2nH2O+2NaOH=Na2SiO3+ (N +1) H2O
Can react with hydrofluoric acid SiO2nH2O+4HF=SiF4+ (N +2) H2O
2. Main chemical indexes
SiO2 content (dry) ≥90%
Sieve residue (4.5 identity m) ≤0.5%
Heating reduction: 4.0-8.0%
Burning reduction :(dry) ≤7.0%
PH: 5.0 to 8.0
Total copper content: ≤30mg/kg
Total manganese content: ≤50mg/kg
Total iron content: ≤1000mg/kg
DBP absorption value: 2.00-3.50cm3/g
Specific surface area: different uses have different range, I plant product control
145-165m2/g (HT2#) 165-185m2/g (HT1#)
(HT3 # 200-300 m2 / g)
3, the main physical properties (with rubber)
Tensile strength ≥ 17.0mpa 500% fixed elongation strength ≥ 6.3mpa
Tensile elongation ≥675%
Four, production principle
Sodium silicate reacts with sulfuric acid to form hydrated silicic acid
heating
Na2O•mSiO2+H2SO4+nH2o-→Na2SO4+mSiO2• (N +1) H2O↓
The reaction finishing liquid was dehydrated by pressure filtration, washed and beaten to get the white carbon black slurry, which was spray dried to get the white carbon black finished product.
